Patent Grant
8590709
1. Field of the Invention
The present invention is directed to a process for pneumatic classification of mixtures of particulates as well as an apparatus and method for pneumatically classifying mixtures of particulates. More particularly, the present invention is directed to a process which classifies a mixture of particulates based primarily upon the aerodynamic support characteristics of the particulates, relative to each other. For example, a mixture of particulates may be classified by the process of the present invention into a fraction of particulates with high aerodynamic support characteristics and a fraction of particulates with low aerodynamic support characteristics. One example of an application of the process of the present invention is vacuuming up, then cleaning and subsequently classifying rock. The rock would be a mixture of particulates, including, but is not limited to, used landscape rock, used or fouled railroad ballast rock, and mining ore. Other applications include cleaning and/or classifying various mixtures of particulates such as mixtures including debris particulates, soils or ores, grains or food materials by or for pneumatic processing. Most particularly, the present invention is directed to a process for separating rock, such as used landscape rock or used railroad ballast rock or ores or lead particulates in soil or backstop materials from associated dirt or debris and/or other materials characterized by having a relatively higher or lower aerodynamic support characteristic and thereby cleaning the used landscape rock, used railroad ballast, or reclaiming the lead particulates or enriching or concentrating the ore, or cleaning grains or food materials.
2. Description of Related Art
There are many forms of decorative ground cover including mulch and decorative rock. Most forms of decorative ground cover deteriorate over time. Mulch decays, fades, and gets carried away by wind, water, animal foraging, and foot traffic. It frequently requires annual replenishment. Decorative rock is stable and lasts for years, but it is also prone to losing its aesthetic qualities. Silt, soil or both washes into the decorative rock from the adjacent ground and from downspout runoff. Decomposed leaves, seeds, sticks, grass trimmings, etc. eventually fill in the decorative ground cover. Over time weeds proliferate because of the accumulation of dirt. In arid areas the buildup of airborne sand is a problem. If located near roadways, there can be a problem with sand from snow removal.
Home owners have struggled to clean their landscape rock in a variety of ways including picking it up manually and cascading it over an improvised screening device while simultaneously hosing it off Such methods are cumbersome, tedious and involve handling the rock multiple times.
Commercial grounds keepers generally opt to just replace the rock, bringing in front-end loaders and other heavy equipment. This is expensive and prone to causing damage to existing lawns and shrubbery. Equipment is currently available for picking up landscape rock by means of a vacuum. Examples of such vacuum systems include U.S. Pat. No. 4,723,971 entitled “Industrial Vacuum Cleaner” issued on Feb. 9, 1988 to Ladislan B. Caldas, U.S. Pat. No. 4,735,639 entitled “Modular Industrial Vacuum Loading Apparatus for Ingesting and Collecting Debris and. Filtering Discharged Air” issued on Apr. 5, 1988 to Duncan Johnstone, the teachings of which are incorporated herein by reference in their entirety, as well as the industrial vacuum sold by Christianson Systems, Inc. of Blomkest, Minn. under the tradename “RockVac.” But, such vacuums do not clean the rock so it can be reused. The old rock, along with accompanying dirt and debris, is often disposed of in landfills, thereby exacerbating a growing ecological problem.
Accordingly, there is a need for an apparatus for cleaning landscape rock that can be made portable for on-site use, that is reliable, that is relatively easy to operate, that is capable of handling rock and debris that is accompanied by broad range of moisture contents, and that does not discharge an appreciable amount of dust to the environment.
The present invention, in one embodiment, is an apparatus that uses vacuum to pick up and clean used landscape rock from associated debris. The preferred embodiment consists of an intake means through which rock and debris are sucked into the apparatus, an entry section, a rock-debris separator chamber, a pre-exhaust, a means of collecting the cleaned rock for reuse, an air-debris separator cell, a means of collecting the debris for disposal or reuse, and a vacuum means consisting of a dust collector and a vacuum blower or pump.
Immediately upon being picked up by vacuum through the intake head, the rocks collide with each other and with the walls of an intake hose where dirt adhering to the rocks is dislodged, thereby initiating the cleaning of the rock that takes place within the apparatus. The flow of air, rock and debris entering through the intake means passes into an entry section, which is a generally horizontal chamber. Within this entry section the rocks continue to collide with each other and with the walls of the entry section, thereby continuing the cleaning process that started within the intake hose. Additionally, the top of the entry section is made to slope downward toward the entry section outlet, thereby deflecting the flow downward as the air, rock and debris leave the entry section.
Upon leaving the entry section, the flow enters a rock-debris separator chamber where the rocks continue to collide with one another and with the walls of the chamber and where the separation of the rock and debris takes place. Because of the larger dimensions of the chamber the velocity decreases substantially, thereby facilitating the separation by gravity of the rock from the debris. The bottom of the chamber slopes downward toward the discharge outlet through which the cleaned rocks are removed and collected in a collection means such as a removable 5-gallon pail or a hopper, from which the rock is periodically removed for reuse. The air and entrained debris is removed through the chamber exhaust outlet on the top of the chamber.
Ambient air is pulled by vacuum into the discharge outlet or the collection means, where it flows upward through the discharge outlet into the chamber and out through the chamber exhaust along with the main flow of air entering through the intake means. The countercurrent flow of air and rock within the discharge outlet entrains the debris, but not the denser rock as it leaves the chamber. This upward airflow from the discharge outlet also assists in carrying the separated debris upward toward the chamber exhaust outlet.
Another embodiment of the chamber design involves an auxiliary air supply directly to the chamber, entering on the side opposite the chamber inlet and works in conjunction with another embodiment, a flexible impaction shield. Both minimize the accumulation of damp debris on the chamber walls resulting from the direct, high velocity impact of air on the inner walls of the chamber.
The chamber may also have an access means to allow personnel to inspect, repair and maintain the inside of the chamber. The velocity of the flow of air, rock and debris within the chamber is further reduced by another aspect of the preferred embodiment, the pre-exhaust. The pre-exhaust abruptly withdraws a portion of the entering air from the entry section, the inlet side of the chamber or from the top of the chamber with the aid of a partition located close to the inlet side of the chamber. If the partition is employed, it extends preferably from just above the top of the chamber inlet to the chamber exhaust outlet. The top portion of the partition is pivotally connected to the bottom portion of the partition so that it can be adjusted to alter the relative flow rates of air leaving through the pre-exhaust outlet and the chamber exhaust outlet.
In the present invention, chamber air supply means including a valve directed to outside the chamber controls flow of ambient air into the chamber which flow of ambient air is separate from the at least a portion of the airstream from the intake that is directed into the chamber. This separate flow of ambient air is drawn into the chamber through the chamber air supply means and then upward through the chamber discharge outlet.
The air and debris exhausted from the pre-exhaust outlet and the chamber exhaust outlet flows vertically upward to the air-debris separator cell, or cell, located directly above the chamber. The cell is oriented horizontally and is substantially cylindrical or oval in configuration. The entering air undergoes a rapid decrease in velocity due to the much larger dimensions of the cell, thereby allowing the debris to separate from the air primarily by gravity settling.
There are many possible configurations of cell inlets and outlets, but the preferred arrangement is for the flow to enter vertically in an upward direction in the cell bottom portion of the cell middle section. The location of the vertical cell inlet(s), as it penetrates the circumference of the cell, lies between radial and tangential, though closer to the latter is preferred. This configuration minimizes the direct high-velocity impingement of damp debris with the inner wall of the cell nearest the point of entry.
Two cell end sections are formed within the cell by vertical baffles that extend from the cell top portion partway into the cell bottom portion. Air is withdrawn through cell exhaust plenums located in the top of each cell end section. Cell exhaust plenums in both cell end sections contain cell exhaust outlets. Cell exhaust plenum inlets, disposed in both cell end sections, may comprise filters or inlet ducts in the top portion of each end section.
Damp debris and dry debris exhibit significant differences in their air handling characteristics, which can affect the buildup of damp debris within the cell and the efficiency of separation. Two embodiments, a flexible impaction shield and a damp debris grate, minimize the buildup of damp debris. Two additional embodiments, internal baffles and a dry debris grate, maximize the separation efficiency with dry debris.
Gravity settling of debris occurs along all or most of the flow path within the cell and debris is collected within the bottom portion of the cell and periodically removed by manual or automatic means. Collected debris, which is a by-product of the cleaning operation, can be disposed of or it can be used, among other things for leveling under the landscape fabric or plastic sheet to restore the rock bed.
The exhaust air from the air-debris cell flows to a vacuum source, consisting of a vacuum blower or a mechanical vacuum pump and a dust collector such as a bag collector, where the dust collector is located after blower or before the pump, depending on which device is used to generate the vacuum.
In another embodiment of the invention, the intake means may be connected directly to the rock-debris separation chamber, thereby eliminating the entry section; though its inclusion in the apparatus is preferred.
The foregoing embodiments of the invention satisfy the operational requirements of a portable apparatus for picking up and cleaning landscape rock and other similar solids, the need for which is well understood.
In another embodiment of the invention, an apparatus is disclosed that vacuums up debris only, including moist or damp debris, and collects the debris so that it can be disposed of appropriately. This embodiment includes an intake means, an air-debris separator cell, a debris collection means, and a vacuum means, but not a rock-debris separator chamber.
In another embodiment of the invention, an apparatus is disclosed that vacuums up both rock and debris, in which the cleaned rock is collected for reuse, but which does not include an air-debris separator cell.
The above described features and other features and advantages of this invention and the manner of realizing them will become more apparent, and the invention itself will be best understood, from a study of the following description and appended claims, with reference to the attached drawings showing the preferred embodiments of the invention. It should be understood that the particular specifications, configurations or geometrical relationships of the invention are exemplary only and are not to be regarded as limitations of the invention. Nor is the invention, particularly as it pertains to the rock-debris separator chamber, in any way invalidated by the substitution of alternative means of separation of air and debris or particulate matter that are well-known to those skilled in the art. Further, the applicability of the invention is not limited to on-site cleaning of landscape rock using a portable version of this invention. The invention described herein may also be used in larger-scale stationary operations to which rock is routinely hauled from many sites.
In another embodiment, the present invention is a process for picking up and cleaning ballast rock. The process includes the steps of -providing an apparatus for picking up and cleaning ballast rock including: an intake having a head at one end and an outlet at the other end, a chamber having a bottom, an inside and an outside and a chamber inlet fluidly connected to the outlet end of the intake and disposed to receive an airstream from the intake and to direct at least a portion of the airstream from the intake into the chamber, the airstream capable of entraining rock and debris within the airstream, the chamber having a chamber exhaust outlet for discharging air and debris from the chamber, the chamber having a chamber discharge outlet located on the bottom of the chamber for discharging ballast rocks falling by gravity through and from the chamber, a vacuum source for producing vacuum, the vacuum source fluidly connected to the chamber, whereby the airstream is drawn into the chamber by vacuum applied through the intake to the head end of the intake; whereby ballast rock and debris is vacuumed into the intake at the head end of the intake forming an airstream with entrained ballast rock and debris and wherein the airstream with entrained ballast rock and debris is transported to the chamber whereafter the ballast rock and debris of the airstream with entrained ballast rock and debris enters the chamber at the chamber inlet and the velocity of the airstream with entrained ballast rock and debris slows thereby allowing the ballast rock to fall under gravity to the chamber discharge outlet while the debris exits the chamber through the chamber exhaust outlet. Optionally, but preferably, a pre-exhaust is also present and facilitates reducing the velocity of the airstream to better allow ballast rock to fall. Such a pre-exhaust is connected to a vacuum. Having provided such an apparatus, the next step is vacuuming ballast rock and debris into the intake at the head end of the intake of the apparatus. Then the step of transporting the ballast rock into the chamber by the airstream created by applying vacuum to the head end of the intake is undertaken. Next, the step of slowing the velocity of the airstream with entrained ballast rock and debris in the chamber thereby allowing the ballast rock to fall under gravity to the chamber discharge outlet while the debris exits the chamber through the chamber exhaust outlet is implemented.
In another embodiment, the present invention is a method of removing and cleaning fouled ballast rock. This method includes the steps of: creating an airstream containing ballast rock, the airstream moving through an intake having sides and then colliding the ballast rock with each other and with the sides of the intake to dislodge dirt adhering to the ballast rock. In yet another embodiment, the present invention is a method for separating a mixed granular material into two segregated populations of granules. In the method of this embodiment, the two segregated populations of granules are each characterized by a dissimilar range of specific gravity. These two populations may be understood as defining, first, a high specific gravity range granular material and defining, second, a low specific gravity range granular material. The method for separating the two populations includes the steps of: providing an initial airstream; incorporating the mixed granular material into the initial airstream; slowing the initial airstream to allow the high specific gravity material to fall; providing a second airstream with an upward direction and directing the second airstream against the falling high specific gravity material to air-wash the falling high specific gravity material; and collecting the air-washed high specific gravity material. The second, upwardly directed, airstream is preferably driven by ambient pressure air moving toward the vacuum pressure within the chamber. The low specific gravity material may be collected subsequently, thereby separating the two populations. The method is applicable to mixtures of spent firearms projectiles and backstop material, such as for example, mixtures of lead bullets (high specific gravity population) and rubber pellets (low specific population) or mixtures of lead bullets (high specific gravity population) and sand (low specific gravity population) or mixtures of lead shot (high specific gravity population) and dirt (low specific gravity population), all of which might be encountered in recovering lead from firing ranges. Preferably, the mixture has been screened or otherwise limited in particle size. That is, the method effectiveness suffers when excessively large particles are present in the mixture, for example large rocks in mixtures with dirt and spent lead may degrade the effectiveness of the separation, either by plugging passages or by large rocks behaving differently than the smaller particle sized dirt population in airstreams or requiring excessively high velocity airstreams to incorporate the mixture into the airsteam. Screening, for example, can limit such problematic size distribution degradation by removing large rocks from the lead and dirt mixture prior to incorporation into the initial airstream. Incorporation of the mixture into the initial airstream can be by vacuuming through a hose or mechanically dispensing the mixture into the airstream, for example, by dropping screened mixtures into a suitable initial airstream or by elevating the mixture into an airstream or by horizontally advancing the mixture into an airstream. The step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, preferably includes a step of providing a pre-exhaust, such as earlier described with respect to cleaning landscape rock. Preferably, the provided pre-exhaust abruptly removes a portion of the initial airstream prior to a directional change of the airstream to approximately vertical and upwardly directed. Preferably, the slowed initial airstream turns approximately vertical and upwardly in direction. Preferably, momentum of the suspended mixed granular material along with the slowed initial airstream carries the mixed granular material forward as the slowed initial airstream turns approximately vertical. More preferably, with respect to the initial air stream slowing, the percentage of air removed by the provided pre-exhaust from the initial airstream is from about 35% to about 50% of the volume of the initial airstream. Preferably, the initial airstream is confined within a first cross-sectional area and further wherein the step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, includes a step of expanding the confining cross-sectional area to a second cross-sectional area, greater than the first cross-sectional area. Preferably, combining the second airstream with the slowed initial airstream, results in any removed low specific gravity range granular material air-washed from the falling high specific gravity range material rejoining the slowed, initial airstream and the main portion of the population of the low specific gravity range granular material suspended therein. Preferably, the low specific gravity range granular material is subsequently removed from the slowed initial airstream by further slowing the slowed initial airstream to a third velocity, the third velocity slower than the second velocity, such that the low specific gravity range granular material falls from the third velocity airstream. The low specific gravity range granular material falling from the third velocity airstream is then collected. As noted earlier, preferably, the mixed granular material to be separated is pre-screened to a predetermined range of size. Preferably, the mixed granular material to be separated is pre-dried to predetermined moisture content.
In another embodiment, the present invention is a method for separating a mixed granular material into two segregated populations of granules, the two segregated populations of granules each characterized by a dissimilar range of specific gravity and defining a high specific gravity range granular material and a low specific gravity range granular material. The method for separating includes the steps of: providing an initial airstream, the initial airstream having a first velocity capable of suspending the mixed granular material; incorporating the mixed granular material into the initial airstream to suspend and transport the mixed granular material; slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, such that the high specific gravity range granular material falls from the slowed, initial airstream and the low specific gravity range granular material remains suspended in the slowed, initial airstream; providing a second airstream, the second airstream upwardly directed and arranged to have a counter-current relationship to the falling high specific gravity range granular material, the second airstream having a velocity insufficient to entrain the falling high specific gravity range granular material but sufficient to entrain any low specific gravity range granular material; subjecting the falling high specific gravity range granular material to the second airstream, so as to air-wash the falling high specific gravity granular material and remove any low specific gravity range granular material accompanying the falling high specific gravity range granular material; and collecting the air-washed high specific gravity range granular material falling from the second airstream. Preferably, the step of incorporating the mixed granular material into the initial airstream, includes vacuuming up the mixed granular material into the initial airstream or mechanically dispensing the mixed granular material into the initial airstream. Preferably, the step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, includes providing a pre-exhaust, the provided pre-exhaust abruptly removing a portion of the initial airstream prior to an upwardly directed directional change of the airstream to approximately vertical and wherein the slowed initial airstream turns approximately vertical and wherein momentum of the suspended mixed granular material along with the slowed initial airstream carries the mixed granular material forward as the slowed initial airstream turns approximately vertical. Preferably, the slowing results from a percentage of the air removed by the provided pre-exhaust from the initial airstream in the range of from about 35% to about 50% of the volume of the initial airstream. Preferably, the initial airstream is confined within a first cross-sectional area and the step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, includes expanding the confining cross-sectional area to a second cross-sectional area, greater than the first cross-sectional area. Preferably, the second airstream, including any removed low specific gravity range granular material air-washed from the falling high specific gravity range material combines with the slowed, initial airstream including the suspended low specific gravity range granular material. Preferably, the low specific gravity range granular material is removed from the slowed initial airstream by further slowing the slowed initial airstream to a third velocity, the third velocity slower than the second velocity, such that the low specific gravity granular material falls from the third velocity airstream. The low specific gravity range granular material falling from the third velocity airstream is then collected. As explained previously, preferably, the mixed granular material to be specific gravity separated is pre-screened to a predetermined range of size. Preferably, the mixed granular material to be specific gravity separated has a pre-determined moisture content. This moisture content may be achieved by pre-drying. Alternatively, some moisture may be removed by incorporation into the initial airstream. Excessive moisture may sometimes interfere with the incorporation into the initial airstream by causing the mixed granular material to stick together. Preferably, the high specific gravity range granular material may consist of various types of higher density components and the low specific gravity range material may consist of various types of lower density components. Preferably, the high specific gravity range granular material originates in a firearm projectile and the low specific gravity range material originates in a firing range backstop material. More preferably, the high specific gravity range granular material includes metallic lead and the low specific gravity range material originates in a firing range backstop material.
In yet another embodiment, the present invention is a process for dry enrichment of a precious metal ore, the precious metal ore having a particle size distribution with an upper size limit and having fines below the upper size limit, the precious metal ore including rock and a precious metal having a density greater than the rock. The process includes the steps of: providing an airstream for entraining the precious metal ore, the airstream having an entrainment velocity; entraining and conveying the precious metal ore to a container using the airsteam at the entrainment velocity; reducing velocity of the airstream to a lower velocity, the lower velocity insufficent to entrain at least the upper size limit particles of the particle size distribution of the precious metal ore, such that at least the upper size limit particles exit the airstream, while at least some of the fines remain entrained in the lower velocity airstream; and, collecting the upper size limit particles exiting the airstream. In another embodiment, the present invention may be understood, as a process for pneumatic classification of a mixture of granular particulates into a low aerodynamic support fraction of particulates and a high aerodynamic support fraction of particulates. The process includes the steps of providing an apparatus, entraining, by vacuuming or otherwise dispensing the mixture of granular particulates into the airstream, transporting the entrained mixture of granular particulates into a chamber of the provided apparatus, and reducing velocity within the chamber thereby allowing the low aerodynamic support fraction to fall. More specifically, in the inventive process, the provided apparatus includes: an intake, a chamber, means for reducing velocity, a vacuum source and means for creating a vertical airflow. Even more specifically, the intake has a head at one end and an outlet at the other end. The chamber has a bottom, an inside, an outside, a chamber inlet, a chamber exhaust outlet, and a chamber discharge outlet. The chamber inlet is fluidly connected to the outlet end of the intake and disposed to receive an airstream from the intake and to direct at least a portion of the airstream from the intake into the chamber. The airstream, within the intake, is characterized by a capability of entraining the mixture of granular particulates which are to be classified. The chamber exhaust outlet is capable of discharging the airstream and the high aerodynamic support fraction particulates entrained within the airstream from the chamber. The chamber discharge outlet is located on the bottom of the chamber and is for discharging previously entrained, low aerodynamic support fraction particulates which have or are falling by gravity through and from the chamber. The means for reducing the velocity of the airstream within the chamber, preferably includes a pre-exhaust located proximate or near the chamber inlet. The pre-exhaust has a pre-exhaust inlet and a pre-exhaust outlet. Optionally, the pre-exhaust may be adjustable as to position and/or cross-section and/or airstream volume which may pass therethrough. Preferably, the vacuum source for producing vacuum is fluidly connected to the chamber exhaust outlet. Preferably, the pre-exhaust outlet is also fluidly connected to the vacuum source. Alternatively, the pre-exhaust outlet may be connected to another vacuum source, distinct from the vacuum source connected to the chamber exhaust outlet. When the airstream is drawn through the intake and into the chamber by vacuum applied to the chamber and thereby through the intake to the head end of the intake, a mixture of granular particulates is vacuumed into the intake at head end of the intake forming an airstream with an entrained mixture of granular particulates. The airstream with the entrained mixture of granular particulates is transported through the intake to the chamber and enters the chamber at the chamber inlet and the velocity of the airstream with the entrained mixture of granular particulates then slows or is reduced in velocity thereby allowing the low aerodynamic support fraction particulates to fall under gravity from the reduced velocity airstream to the chamber discharge outlet. The means for creating a vertical airflow in the chamber discharge outlet includes an air admittance means for providing vertical airflow countercurrent to falling low aerodynamic support fraction particulates so as to airwash remove any high aerodynamic support fraction particulates inadvertently falling with the low aerodynamic support fraction particulates into and through the chamber discharge outlet. Optionally, this vertically directed upward airflow, countercurrent to the falling particulates, is adjustable. In the process, one early step is entraining the mixture of granular particulates in the airstream. This may be by vacuuming the mixture of granular particulates into the head end of the intake to entrain the mixture of granular particulates. Alternatively, the mixture of granular particulates may be dispensed into the airstream to entrain the mixture of granular particulates. The entrained mixture of granular particulates is transported through the intake and into the chamber. The velocity of the airstream bearing the entrained mixed particles is reduced within the chamber thereby allowing the low aerodynamic support fraction particulates to fall under gravity to the chamber discharge outlet. Meanwhile, the high aerodynamic support fraction particulates exit the chamber through the chamber exhaust outlet. The process can be applied to a broad range of mixtures. More specifically, the process is applicable where the mixture of granular particulates is selected from the group of mixtures of granular particulates consisting of: landscape rock, dirt and debris; almonds and orchard trash, sticks, dirt, leaves; plastic pellets and fines and tails; coarse sand and fine sand; sand and tailing materials, fines and dust; blast media and paint chips, rust, and dust; coarse blasting media and fine blasting media; railroad ballast, fractured ballast, dirt and debris; lead pellets and dirt and debris; lead bullets and backstop material and dirt and debris; glass and shredded paper; dense ore minerals and pea gravel and dirt; shot media and worn shot media and dust; and agricultural grain/seed/soy beans and chaff, stems and weed seed.
For the purposes of this patent the terms defined in this section shall have the following meanings unless otherwise provided, described or indicated by the context.
Debris is defined as a mixture of one or more of the following: soil, inorganic materials such as silt, or sand and organic materials such as decomposing or decomposed leaves, grass clippings, plant clippings, seeds, sticks and weeds, all accompanied by varying amounts of moisture.
Landscape rock or rock is defined as any naturally occurring rock or stone, both as is or crushed, or similar man-made solid materials used as a landscape material, having a specific gravity of at least 1.25, and with the linear dimension of the particles ranging from about 0.5 inches to about 3.5 inches.
Solids are defined as any solid materials, including rock used for other purposes, both naturally occurring and man-made, which have a variety of end uses requiring cleaning or separation, with a specific gravity of at least 1.25.
Airflow or airstream are used interchangeably and are defined as a flow of air resulting from the application of vacuum which airflow or airstream may contain entrained rock, dirt or debris.
Entrained or suspended is defined as a situation in which particles, granular particulates, rocks, debris and/or other solids are carried by an airstream. An airstream which slows in velocity becomes increasingly unable to entrain or suspend such materials and renders them susceptible to falling due to gravity.
Aerodynamic support is defined as the lifting effect of a vertical airflow on an object or particle in a gravitational setting. Aerodynamic support is governed primarily by the gas, typically air, and velocity of the air, drag force of the component involved, weight and the opposing influence of gravity on the particulates. By way of examples, low aerodynamic support characteristics render such a material or particle more difficult to maintain in an entrained or suspended condition, while high aerodynamic support characteristics render such a material or particle more easily maintained in an entrained or suspended condition.
Throughout this description, an element referred to by a reference number has the characteristics and attributes described in association with that element wherever such element is referred to unless specifically directed otherwise.
First an overview of the invention is presented followed by a detailed description of the invention. The invention is an apparatus, generally labeled 10, for on-site cleaning of landscape rock as shown in
The apparatus 10 operates under vacuum and, in one embodiment, includes the following main elements. An intake 20 suctions rock and associated debris off the ground and conveys it either directly to a rock-debris separator chamber 40 or to the rock-debris separator chamber 40 through an entry section 30 (
The settling of rock in chamber 40 is facilitated by a reduction of the velocity of the flow in chamber 40 by use of a pre-exhaust 90 abruptly withdrawing air from entry section 30 or chamber 40 and the greater size of chamber 40 relative to intake 20 and entry section 30.
An air-debris separator cell 100 is provided to remove debris from the airflow moving from pre-exhaust outlet 94 and chamber exhaust outlet 52. The air-debris separator cell 100 is designed so the debris settles out of the air by gravity and is collected separately for periodic removal.
As noted previously, ambient air is drawn into the lower part of chamber 40 or into chamber collector means 70 below chamber 40 through chamber air supply means 80 (
A vacuum means 130 creates a vacuum to establish the necessary airflow in apparatus 10. The function of the vacuum means 130 is to draw ambient air into apparatus 10 through intake means 20, chamber air supply means 80, and auxiliary chamber air supply means 82, resulting in the rock and debris being picked up and transported through the apparatus 10, the rock being cleaned by separating rock from the debris, and the rock and debris being collected separately. Vacuum means 130, which includes a dust collector 136, discharges to the atmosphere.
Because damp debris is prone to adhering to the inner surfaces of the apparatus 10 when the air stream carrying the debris impacts the surfaces at a high velocity and/or at an acute angle, several measures, each of which is an independent invention, have been taken in the design of the apparatus 10 to minimize this problem. They include: removing the debris from the air stream as quickly as possible by the use of an air-debris separator cell 100 situated directly above the chamber 40; keeping connecting conduits as short and straight as possible; avoiding, as much as possible, the high velocity contact of debris-containing air streams directly onto the inner surfaces of the apparatus 10; provision of an auxiliary chamber air supply means 82 into the chamber 40, and the use of flexible impaction shields 84 and 86 as will be described hereafter.
A detailed description of the invention follows. Those portions of the apparatus 10 in contact with rock must be made of durable materials able to resist the abrasion and impact of the moving rock. In the preferred embodiment of the invention, rock and associated debris are suctioned into the apparatus 10 through intake 20 (
Hose 24 can be a hose, conduit or a flexible assembly of rigid metal or plastic piping configured to allow the head 22 to move in three dimensions. The hose 24 connects through outlet 25 to an entry section 30 (
A rock-debris separator chamber or chamber 40 separates debris from rock as shown in
The chamber inlet 44 is oriented approximately vertically and is preferably part of and parallel to the chamber inlet side 42 in the immediate vicinity of chamber inlet 44. The chamber inlet 44 has a chamber inlet uppermost point 45 at the highest elevation of chamber inlet 44. The chamber inlet 44 receives flow from the entry section outlet 34 if an entry section 30 is used (
Pre-exhaust 90 abruptly withdraws a portion of the air entering the apparatus 10 through the intake 20 to reduce the velocity of the remaining flow in chamber 40. Pre-exhaust 90 comprises a pre-exhaust inlet 92 proximate the chamber inlet 44, a pre-exhaust outlet 94 opposite the pre-exhaust inlet 92 and a pre-exhaust midsection 96, a closed conduit connecting the pre-exhaust inlet 92 to the pre-exhaust outlet 94. The pre-exhaust inlet 92 is located near the chamber inlet 44 and directs a portion of the airflow entering the intake 20 into the pre-exhaust midsection 96 where it is directed to the pre-exhaust outlet 94.
Pre-exhaust 90 is formed, in part, by chamber partition 58. Chamber partition 58 can have many shapes and configurations including a simple plane that approximately faces the chamber inlet 44.
The partition upper portion 64 is pivotally connected to partition lower portion 60 at pivot point 68 so that partition upper portion 64 can be rotated to control the relative flow areas on each side of the partition upper portion 64 in the chamber exhaust outlet 52. Partition lower edge 62 is generally horizontal and set preferably at or slightly above the elevation of the chamber inlet uppermost point 45 so that most if not all of the passing rock does not impact the partition lower edge 62 or partition lower portion 60. Partition lower edge 62 could be set higher, as high as proximate the chamber top portion 50, but with diminishing effect. Partition lower edge 62 could also be set lower than the preferred elevation, but would then be exposed to the impact of rock and debris.
The pre-exhaust inlet 92 in this preferred embodiment is a planar area formed by a plane through and bounded by the partition lower edge 62 and chamber inlet uppermost point 45 and the intersection of that plane with the chamber inlet side 42. Pre-exhaust outlet 94 is formed within the chamber exhaust outlet 52 and is a planar area formed by the partition upper edge 66 and the chamber exhaust outlet 52 on the chamber inlet side 42 of the chamber exhaust outlet 52. The pre-exhaust mid-section is bounded by chamber partition 58 and the chamber inlet side 42, and by the pre-exhaust inlet 92 and the pre-exhaust outlet 94.
There are three other embodiments of the pre-exhaust 90 that do not require the chamber partition 58 to form the pre-exhaust 90. A second embodiment shown in
A third embodiment shown in
The fourth embodiment, shown in
Now, turning to the other elements connected to the chamber 40, a chamber collector means 70 is disposed adjacent to and below the chamber discharge outlet 56. The chamber collector means 70 comprises a collection container 72 such as a common five gallon pail which is removable and has an airtight connection to the chamber discharge outlet 56 when the apparatus 10 is operating. Alternatively, the chamber collector means 70 may be one or more integral hoppers that discharge to other containers or onto a conveyer.
A chamber air supply means 80,
An air-debris separator cell 100 shown in
The air-debris separator cell 100 comprises a cell middle section 102, a first end section 104, a second end section 106, a cell bottom portion 108, a cell top portion 110, a vertical baffle 116, a cell exhaust plenum 119 with associated inlet duct 140 that enters into the plenum 119 at 143 (
To simplify the remaining description concerning the air-debris separator cell 100 only the single cell inlet 111 embodiment is described but the same description applies as well to the embodiment of air-debris separator cell 100 with the cell pre-exhaust inlet 112 and separate cell chamber exhaust inlet 113.
Two vertical baffles 116 are disposed in the cell top portion 110 that extend downward from top portion 110 toward cell bottom portion 108, forming cell middle section 102, first end section 104 on one side of cell middle section 102, and a second end section 106 on the opposite side of cell middle section 102.
Air-debris separator cell 100 may have many possible arrangements of cell inlet 111 and cell exhaust outlet 114. Here cell inlet 111 is approximately vertical and disposed in the cell bottom portion 108 of the cell middle section 102 and extends into air-debris separator cell 100. The vertical cell inlet 111 is further located to enter air-debris separator cell 100 at a point on the circumference of the bottom portion 108 such that the vertical extension of the centerline of cell inlet 111 intersects the radius from the axis 144 at a point within about 70-90 percent of the distance along the radius from the axis 144.
A cell exhaust plenum 119 containing exhaust outlet 114 is disposed internal or external of cell top portion 110 of first end section 104 and a second exhaust plenum 119 and exhaust outlet 114 is similarly disposed in the second end section 106. Exhaust plenum inlet comprises filter 118 or an array of inlets 145 and 141 connected by ducts 140 to the exhaust plenum and disposed in the cell top portion 110 of each end section 104 and 106 (
In the preferred embodiment of the invention, shown in
In essence, the flow into the air-debris separator cell 100 has the highest velocity at the point of entry into the air-debris separator cell 100 at cell inlet 111, from which the flow disperses rapidly, follows the inner surface of the cell middle section 102 of the air-debris separator cell 100, rising initially (i.e., moving toward the cell top portion 110) then turning and flowing downward (i.e., moving toward the cell bottom portion 108). As the airflow moves downward, it separates increasingly into two streams, each of which flows under a vertical baffle 116 and then upward (i.e., moving toward the cell top portion 110) through filter 118 or inlet ducts 140 through exhaust plenum 119 to the cell exhaust outlet 114 (
A cell collector 120, shown in
As explained above, the airstream velocity slows upon entering the large volume of the air-debris separator cell 100, and also by friction with the inner wall of the air-debris separator cell 100. In conjunction with the physical location of cell inlet 111 in the cell bottom portion 108, it has been found to be desirable to make the air-debris separator cell 100 somewhat elongated in the vertical direction so that the airstream entering the air-debris separator cell 100 at cell inlet 111 has a greater distance or time to disperse before contacting the inner wall of the cell top portion 110 of the air-debris separator cell 100. The greater vertical dimension also favors gravity settling by allowing more time for the debris to settle out of the airflow before the air is exhausted from air-debris separator cell 100.
An alternative is provided to filter 118 being used as an inlet to exhaust plenum 119. The filter 118 provides an even distribution of airflow in end section 104 and 106, as previously stated, but may require a high level of filter maintenance in some applications. The preferred embodiment (
The purpose of inlet 141 is to remove a portion of the air directly from cell middle section 102 to reduce the rate of flow of the remaining airflow moving under vertical baffle 116, thus increasing the opportunity for the entrained debris to fall to the cell collector 120. The air removed through inlet 141 is relatively void of heavy particulates because the air is extracted from the side of the entering airflow and the momentum of the debris is aligned with and in the same direction of the main airflow.
Using inlet ducts 140 as described with the optional but preferred inlet 141, it is believed that about 70-90% of the air entering the air-debris separator cell 100 passes below vertical baffle 116 through the cell bottom portion 108 and about 10-30% through baffle 116 at inlet 141 and consequently out of the air-debris separator cell 100. Using inlet ducts as described without optional inlet 141, 100% of the air entering the air-debris separator cell 100 passes below vertical baffle 116.
This movement of air from the cell inlet 111 around the inside of the air-debris separator cell 100 is shown in
Air-debris separator cell 100 further comprises at least one bottom flow control baffle 117, as shown in
Damp debris and dry debris have significant differences in their air handling characteristics; damp debris weighs more and readily settles out of an airstream but is prone to building up on the inner surfaces of air-debris separator cell 100 due to the direct high velocity impact of the debris containing airstream with the inner surfaces as previously discussed. Dry debris is more difficult to remove from an airstream because it is lighter, and once it does settle out by gravity action, it may re-enter the airstream unless shielded from the main airflow. Excessively damp or wet debris is not recommended for this application.
To achieve the best performance of the air-debris separator cell 100, the operator determines if the debris is damp or dry and sets up the apparatus accordingly. For dry debris this involves installing a top flow control baffle 115 (
Bottom flow control baffles 117 are permanently positioned in cell middle section 102 above the cell collector 120 on opposite sides of the cell collector 120 to produce a first bottom flow control baffle 128 and a second bottom flow control baffle 129. The first bottom flow control baffle 128 is located on the side of the cell collector 120 nearest inlet 111 and directs the airstream impacting the first bottom flow control baffle 128 from above over the collector means 120 (
When the air-debris separator cell 100 is set up for damp debris, a damp debris grate 123 is positioned in or adjacently above the cell collector 120. The damp debris grate 123 consists of a series of parallel plates 127 parallel to the horizontal axis of the air-debris separator cell 100. Each plate 127 preferably increases in height moving from the inner wall opposite the cell inlet towards the cell inlet 111. The function of the damp debris grate 123 is to interact with and turn the airstream flowing across the top of collector means 120 to distribute more of the damp debris in end sections 104 and 106 of collector means 120 (
When the air-debris separator cell 100 is set up for dry debris, a dry debris grate 121 is positioned in or adjacently above the cell collector 120. The dry debris grate consists of a series of parallel plates 125 placed along the horizontal axis of the air-debris separator cell 100, as can be seen in
When the air-debris separator cell 100 is set up for dry debris, a top flow control baffle 115 is positioned in cell top portion 110 of cell middle section 102 opposite the inlet side and against the inner wall of the air-debris separator cell 100 (
One function of the top flow control baffle 115 is to direct a portion of the airstream impacting the top flow control baffle 115 toward and across the interior of the cell middle section 102 where it can contact the airstream entering the air-debris separator cell 100 through cell inlet 111 in a direction substantially opposed to or at substantially a right angle (
The majority of the flow directed across the interior of cell middle section 102 by baffle 115 goes around inlet 111 and follows the inner contour of the cell middle section downward wherein it contacts the first bottom flow control baffle 128 from above which in turn directs the flow over the cell collector 120.
The other function of top flow control baffle 115 is to provide an airstream down the inner wall of the air-debris separator cell 100 in middle section 102 opposite the cell inlet 111 (
Specific structures have been disclosed for top flow control baffle 115, vertical baffles 116, bottom flow control baffle 117, ducts and sections which have the function of directing one or more airstreams into configurations that cause the airstreams to lose velocity with the concomitant effect of causing the entrained debris to fall to the cell bottom portion 108 of the air-debris separator cell 100. However, it is understood that other arrangements and configurations of top flow control baffle 115, vertical baffles 116, bottom flow control baffle 117, ducts and sections could be used as will occur to those skilled in the art after evaluating the description of the invention contained herein that also cause the airstreams to lose velocity and, therefore, their ability to retain entrained debris. It is intended that these other arrangements and configurations fall within the scope of the invention.
As mentioned above, build-up of damp debris can occur on interior surfaces of the apparatus 10 at specific locations and develop to the point of interrupting airflow. This is problematic and directly related to the composition of the debris, moisture content, impaction force of the airflow and the angles of impaction involved. By flexing the base to which impacted debris bonds, the adhering debris will break up and either fall downward by gravity or be carried away in the airflow.
Flexible impaction shield 86 utilizes the aforementioned principle and is attached near, and above inlet 111 of the air-debris separator cell 100. The impaction shield 86 (
A chamber flexible impaction shield 84 substantially similar to the impaction shield 86 described, may be placed in the rock-debris separator chamber 40, opposite and facing the chamber inlet 44 flow (
Cell collector 120 preferably includes a trough or depression along the bottom of the air-debris separator cell 100. Several cell debris removal means 122 are possible such as manual removal of debris using a hand rake-like tool or an auger (
Vacuum means 130 preferably comprises a positive displacement vacuum pump 132 preceded by dust collector 136 or a centrifugal vacuum blower 132 followed by a dust collector 136 and powered by blower motor 134 (
It is desirable to control the vacuum applied by vacuum means 130 to provide the necessary flexibility for handling a variety of materials and maximum productivity. For example, the vacuum may be controlled by varying the speed of the blower motor 134 or by regulating the airflow through adjustable air inlets such as chamber air supply means 80, adjustable air inlets 81 and auxiliary chamber air supply means 82 as shown. One of ordinary skill will understand that the vacuum should be appropriately sized to the material mixture to be entrained or suspended.
In use, the apparatus 10 is moved into position where the head 22 can be near the rock that is to be cleaned. The cell debris removal means cell access 124 is closed so that adequate vacuum can be obtained in the apparatus 10. The vacuum means 130 is activated so that vacuum is generated throughout the device and particularly at intake 20 head 22. Head 22 is placed next to the rock that is to be cleaned whereby the vacuum causes the rock to enter and move through the hose 24 of the intake 20. Under this vacuum, an airstream is created whereby both rock and the associated debris on and around the rock will be brought to and through the intake 20. In all uses of the apparatus 10, if the rock bed is tightly compacted, it may be necessary to loosen the rock or debris by mechanical means such as a pick or shovel or by a rigid claw extending from the head 22. In other embodiments, rather than vacuuming, material may be dispensed into an airstream to cause entraining or suspending.
Upon flowing through the intake 20, the rock and debris moves into the entry section 30 if used and rock-debris separator chamber 40 where the rock is separated from the debris and is collected in the collection container 72. The air, along with the debris moves to the air-debris separator cell 100 where the debris is captured in the air-debris separator cell 100, shown in
The preferred embodiment of the invention provides a method of vacuuming up and separating landscape rock or other solids from associated dirt and debris and thereafter collecting the cleaned rock and separating the debris from the discharge air. This method involves the use of an apparatus 10 having a rock-debris separator chamber 40 and an air-debris separator cell 100, as described above. With this apparatus 10, the user applies sufficient vacuum at the head 22 of intake 20 to cause rock and debris to be pulled into the hose 24, whereafter the airstream leaving hose 24 is directed into the rock-debris separator chamber 40, or, optionally, through the entry section 30 into the rock-debris separator 40. Inside the rock-debris separator chamber 40, the rock is separated from the air and debris as described above. Thereafter, this method includes directing the airstream leaving the rock-debris separator chamber 40 into the air-debris separator cell 100 through the cell inlet 111 or cell pre-exhaust inlet 112 and cell chamber exhaust inlet 113 where both are used. Inside the air-debris separator cell 100, the debris is separated from the air as described above and collected for reuse or disposal.
The preferred embodiment includes a method of cleaning rock. This method includes taking an airstream containing rock and slowing the velocity of the airstream down within the chamber to the point where the airstream can no longer entrain the rock whereupon the rock falls by gravity out of the airstream towards a chamber discharge outlet. This slowing of the velocity of the airstream is accomplished by expanding or increasing the cross-sectional area in which the airstream flows or by abruptly removing a portion of the airstream proximate the chamber inlet 44, or both, resulting in a reduction of the velocity of the airflow traversing through chamber 40.
In this method, debris picked up with the rock will typically be less dense than the rock. As a result, the airstream will continue to entrain most of the debris at a lower velocity than is required to entrain rock. Of course, some of the debris may fall with the rock towards the chamber discharge outlet 56. The chamber 40 has a chamber air supply means 80 that allows an airflow to be drawn vertically and upwardly through the chamber discharge outlet 56. This vertical and upward airflow in the chamber discharge outlet 56 is intense enough to entrain the debris but not intense enough to overcome the momentum of the falling rock. The balance of the airstream entering the chamber 40 through the chamber inlet 44 and the airstream entering the chamber 40 through the chamber air supply means 80 merge in the chamber 40 and carry debris out of the chamber 40 through the chamber exhaust outlet 52, whether the debris is retrieved from the chamber discharge outlet 56 or not.
In addition, the invention also includes another method of cleaning rock in the airstream that picks up rock or debris or both at the intake head 22 of intake 20. This method is an independent method in itself but is preferably combined with the method of cleaning rock described above. This method includes vacuuming up landscape rock by whatever means and causing the rocks vacuumed up to collide with each other and the sides of the vacuum hose 24 in a turbulent airflow to dislodge dirt and debris from the rocks. As a result, the rocks have been cleaned in that a portion of the dirt or debris has been separated from the rocks.
The air-debris separator cell 100 includes a method of separating air from debris, including any rock that may be present. This method includes directing the airstream into configurations that disperse the airstream, split the airstream into smaller segments, impede the airstream or a combination thereof, to slow the velocity of the airstream down to the point that the airstream is unable to entrain the debris. The debris and any rock present fall under the influence of gravity to the cell collector 120.
This method of directing an airstream commences as the airstream containing debris is directed vertically into the air-debris separator cell 100 through cell inlet 111 located on the bottom portion 108 of the air-debris separator cell 100. The airstream disperses as it leaves the confines of cell inlet 111 and enters the relatively large area of the cell middle section 102. The flow continues to disperse as it follows the inner contour of the cell middle section 102 located between the two vertical baffles 116, rising initially then, through contact with the cell top portion 110, turning downwards towards the cell bottom portion 108. As the flow passes the confines of vertical baffles 116, the airstream increasingly splits and is drawn toward the cell exhaust plenums 119 located in the cell top portion 110 of the first end section 104 and second end section 106. As stated above, the cell exhaust plenums 119 preferably have a horizontal array of inlets 145 that further segments and disperses the vertical airflow approaching the cell exhaust plenum 119 in each respective first end section 104 and second end section 106.
In addition to the method described above, a top flow control baffle 115 is preferably utilized when the use of the apparatus 10 involves dry debris. This top flow control baffle 115 is used to improve the operational efficiency of the apparatus 10 with dry debris. This method also includes a method of directing an airstream wherein the initial downward flow of the airstream in the cell middle section 102, as indicated above, is further directed by the top flow control baffle 115 into at least one additional downward flow path. Both downward flow paths are then directed to contact the bottom flow control baffles 117 from above where the bottom flow control baffles 117 direct the downward flow across the cell collector 120. Both bottom flow control baffles 117 direct the airflows contacting them across the cell collector 120 resulting in substantially head-on contact from opposing airflows that occurs over the top of the cell collector 120. These opposing airflows impede air movement, at least momentarily slowing the velocity of the airstream down and providing another opportunity for the suspended debris to fall from the airstream into the cell collector 120.
A preferred embodiment of the invention also includes a method of preventing the build up of impacted debris on selected interior surfaces of the apparatus 10. This is accomplished by use of flexible impaction shields 84 and 86. Each flexible impaction shield 84 and 86, consisting of a sheet like material as described above, is suspended over a site prone to impaction by debris. When such impaction occurs, it will form on the side of the shield 84 or 86 facing the airflow that produces the impaction. As routine changes to the airflow occur, the flexible impaction shield 84 and 86 will flex, bend and flap, therein dislodging the impacted debris from the shields 84 and 86 into the airstream.
Although the preferred embodiment of apparatus 10 includes both a rock-debris separator chamber 40 and an air-debris separator cell 100, in another embodiment of the invention shown in
In the former embodiment, an apparatus 10 is provided having a rock-debris separator chamber 40 as described above. With this apparatus 10, the user applies sufficient vacuum at head 22 of intake 20 to cause rock to be pulled into the hose 24 in an airstream containing air, rock and debris whereafter the airstream is directed into the rock-debris separator chamber 40 through the chamber inlet 44 or the entry section 30 if used and then through the chamber inlet 44. Inside the rock-debris separator chamber 40, the rock is separated from the air and debris as described above. Because this embodiment does not separate debris from the air prior to vacuum means 130, the invention is preferentially intended to pick up and clean rock containing only a small quantity of dry debris.
In yet another embodiment of the invention shown in
The present invention has been described in connection with certain embodiments. It is to be understood, however, that the description given herein has been given for the purpose of explaining and illustrating the invention and are not intended to limit the scope of the invention. For example, specific examples of the means for creating vacuum pressure have been shown. However, it is clear that an almost infinite number of ways of producing sufficient vacuum could be used as is well understood by those skilled in the art. Consequently, it is intended that all such sources of vacuum are included in the present invention. It is to be further understood that changes and modifications to the descriptions given herein will occur to those skilled in the art. Therefore, the scope of the invention should be limited only by the scope of the following claims and their legal equivalents. For the purposes of these embodiments the following terms are defined to have the following meanings unless otherwise provided, described or indicated by the context. Debris is defined as a mixture of one or more of the following: soil, inorganic materials such as silt, or sand and organic materials such as decomposing or decomposed leaves, grass clippings, plant clippings, seeds, sticks and weeds, all accompanied by varying amounts of moisture. Landscape rock or rock is defined as any naturally occurring rock or stone, both as is or crushed, or similar man-made solid materials used as a landscape material, having a specific gravity of at least 1.25, and with the linear dimension of the particles ranging from about 0.5 inches to about 3.5 inches. Solids are defined as any solid materials, including rock used for other purposes, both naturally occurring and man-made, which have a variety of end uses requiring cleaning or separation, with a specific gravity of at least 1.25. Airflow or airstream are used interchangeably and are defined as a flow of air resulting from the application of vacuum which airflow or airstream may contain entrained rock, dirt or debris. Throughout this description, an element referred to by a reference number has the characteristics and attributes described in association with that element wherever such element is referred to unless specifically directed otherwise.
As depicted in the block diagram of
Incorporation of the mixture into the initial airstream can be by vacuuming through a hose or mechanically dispensing the mixture into the airstream, for example, by dropping screened mixtures into a suitable initial airstream or by elevating the mixture into an airstream or by horizontally advancing the mixture into an airstream. The step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, preferably includes a step of providing a pre-exhaust, such as earlier described with respect to cleaning landscape rock. Preferably, the provided pre-exhaust abruptly removes a portion of the initial airstream prior to a directional change of the airstream to approximately vertical and upwardly directed. Preferably, the slowed initial airstream turns approximately vertical and upwardly in direction. Preferably, momentum of the suspended mixed granular material along with the slowed initial airstream carries the mixed granular material forward as the slowed initial airstream turns approximately vertical. More preferably, with respect to the initial air stream slowing, the percentage of air removed by the provided pre-exhaust from the initial airstream is from about 35% to about 50% of the volume of the initial airstream. Preferably, the initial airstream is confined within a first cross-sectional area and further wherein the step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, includes a step of expanding the confining cross-sectional area to a second cross-sectional area, greater than the first cross-sectional area. Preferably, combining the second airstream with the slowed initial airstream, results in any removed low specific gravity range granular material air-washed from the falling high specific gravity range material rejoining the slowed, initial airstream and the main portion of the population of the low specific gravity range granular material suspended therein. Preferably, the low specific gravity range granular material is subsequently removed from the slowed initial airstream by further slowing the slowed initial airstream to a third velocity, the third velocity slower than the second velocity, such that the low specific gravity range granular material falls from the third velocity airstream. The low specific gravity range granular material falling from the third velocity airstream is then collected. As noted earlier, preferably, the mixed granular material to be separated is pre-screened to a predetermined range of size. Preferably, the mixed granular material to be separated is pre-dried to predetermined moisture content.
The collected high density material will be substantially spent firearms projectiles or range lead. This is improved in economic value, in part, because of the air washing it has received, which renders it more valuable for refining and recovery. In another embodiment, the present invention is a method for separating a mixed granular material into two segregated populations of granules, the two segregated populations of granules each characterized by a dissimilar range of specific gravity and defining a high specific gravity range granular material and a low specific gravity range granular material. The method for separating includes the steps of: providing an initial airstream, the initial airstream having a first velocity capable of suspending the mixed granular material; incorporating the mixed granular material into the initial airstream to suspend and transport the mixed granular material; slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, such that the high specific gravity range granular material falls from the slowed, initial airstream and the low specific gravity range granular material remains suspended in the slowed, initial airstream; providing a second airstream, the second airstream upwardly directed and arranged to have a counter-current relationship to the falling high specific gravity range granular material, the second airstream having a velocity insufficient to entrain the falling high specific gravity range granular material but sufficient to entrain any low specific gravity range granular material; subjecting the falling high specific gravity range granular material to the second airstream, so as to air-wash the falling high specific gravity granular material and remove any low specific gravity range granular material accompanying the falling high specific gravity range granular material; and collecting the air-washed high specific gravity range granular masterial falling from the second airstream. Preferably, the step of incorporating the mixed granular material into the initial airstream, includes vacuuming up the mixed granular material into the initial airstream or mechanically dispensing the mixed granular material into the initial airstream. Preferably, the step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, includes providing a pre-exhaust, the provided pre-exhaust abruptly removing a portion of the initial airstream prior to an upwardly directed directional change of the airstream to approximately vertical and wherein the slowed initial airstream turns approximately vertical and wherein momentum of the suspended mixed granular material along with the slowed initial airstream carries the mixed granular material forward as the slowed initial airstream turns approximately vertical. Preferably, the slowing results from a percentage of the air removed by the provided pre-exhaust from the initial airstream in the range of from about 35% to about 50% of the volume of the initial airstream.
Preferably, the initial airstream is confined within a first cross-sectional area and the step of slowing the initial airstream bearing the suspended mixed granular materials to a second velocity, slower than the first velocity, includes expanding the confining cross-sectional area to a second cross-sectional area, greater than the first cross-sectional area. Preferably, the second airstream, including any removed low specific gravity range granular material air-washed from the falling high specific gravity range material combines with the slowed, initial airstream including the suspended low specific gravity range granular material. Preferably, the low specific gravity range granular material is removed from the slowed initial airstream by further slowing the slowed initial airstream to a third velocity, the third velocity slower than the second velocity, such that the low specific gravity granular material falls from the third velocity airstream. The low specific gravity range granular material falling from the third velocity airstream is then collected. As explained previously, preferably, the mixed granular material to be specific gravity separated is pre-screened to a predetermined range of size. Preferably, the mixed granular material to be specific gravity separated has a pre-determined moisture content. This moisture content may be achieved by pre-drying. Alternatively, some moisture may be removed by incorporation into the initial airstream. Excessive moisture interferes with the incorporation into the initial airstream. Preferably, the high specific gravity range granular material may consist of various types of higher density components and the low specific gravity range material may consist of various types of lower density components. Preferably, the high specific gravity range granular material originates in a firearm projectile and the low specific gravity range material originates in a firing range backstop material. More preferably, the high specific gravity range granular material includes metallic lead and the low specific gravity range material originates in a firing range backstop material.
In yet another application and embodiment of the present invention, a process and apparatus for picking up and cleaning ballast rock, especially fouled ballast rock, such as the fouled ballast rock found in railroads which are in need of track maintenance activities. Ballast rock serves a number of purposes but most importantly provides a bed which stabilizes railroad ties supporting parallel rails. Ballast also serves to keep ties, typically made of wood, relatively dry by allowing rain to drain away, thereby encouraging longer service life. Much like ornamental landscape rock, ballast tends, over time, to become loaded with smaller particles, sand and dirt. This condition is known as “fouling” of the ballast. The present invention allows fouled ballast to be picked up, by vacuuming and cleaned, thereby making it available for reuse. The ballast cleaning and pickup process is applicable to ballast rock (as earlier defined as any naturally occurring rock or stone, both as is or crushed, typically having a specific gravity of at least 1.25 but with the linear dimension of the particles ranging from about 3 inches to about 9 inches. While sizing of the intake, chamber 40 and other components must be increased appropriately to the ballast size, the general operation of the process and apparatus is as earlier explained with respect to landscape rock. One of ordinary skill will be able to appropriately size the components and employ appropriate strength and thickness materials to withstand the impact and wear of ballast rock as well to provide vacuum/airstream appropriate to the more substantial ballast rock. One notable advantage is that the ballast rock may be removed from the rail bed in either the presence or absence of rails and ties with minimal additional effort as the vacuuming progressively removes and picks up the ballast rock. Collisions of the ballast rock with other ballast rock and the walls and sides of the intake facilitates cleaning by dislodging and removing adhering dirt and sand and debris from the ballast rock and allowing such dirt and sand and debris to leave the chamber 40 by the chamber exhaust outlet 52, whereas the ballast rock, which is ready for reuse, leaves chamber 40 by falling through the chamber discharge outlet 56, preferably while receiving a countercurrent air wash by a vertically upward directed airstream passing through the chamber discharge outlet.
In yet another application and embodiment of the present invention, a process and apparatus for enriching precious metal ore, such as gold bearing ore is disclosed. By way of summary, a process for dry enrichment of a precious metal ore is disclosed. The preferred precious metal is gold, however, the process may be used for platinum or palladium or silver or other precious metal ores. The precious metal ore should be understood as having a particle size distribution with an upper size limit and having fines below the upper size limit, the precious metal ore including rock and a precious metal having a density greater than the rock. The process includes the step of, first, providing an airstream for entraining the precious metal ore, the airstream having an entrainment velocity. Next, the ore is entrained and conveyed as the precious metal ore to a container using the airsteam at the entrainment velocity. Next, the velocity of the airstream is reduced to a lower velocity, the lower velocity being insufficent to entrain at least the upper size limit particles of the particle size distribution of the precious metal ore, such that at least the upper size limit particles exit the airstream, while at least some of the fines remain entrained in the lower velocity airstream. Then, the upper size limit particles exiting the airstream are collected. The process is a dry enrichment of precious metal ore in the collected particles exiting the reduced velocity airstream results from the process or alternatively the process is a dry enrichment of precious metal ore in the particles remaining entrained in the reduced velocity airstream results from the process. Preferably, the precious metal ore is screened to provide the upper size limit prior to entraining in the airstream.
In a more advanced embodiment, the process step of reducing velocity of the airstream at a second reduced velocity, the second reduced velocity being lower than the reduced velocity previously employed, wherein a dry enrichment of precious metal ore in the particles remaining entrained in the reduced velocity airstream results from the reduced velocity and the second reduced velocity results in dry enriched ore exiting the airstream and then collecting the particles exiting the second reduced velocity airstream. In such a more advanced embodiment of the process, the second velocity reduction further enriches the precious metal ore by retaining entrained fines with a lower content of precious metal than particles exiting the second reduced velocity airstream for collection. One preferred subprocess which may occur and render the process particularly useful in enriching ore is that the step of entraining and conveying results in collisions of precious metal bearing particles within the particle size distribution such that the particle size distribution is shifted to smaller particles and enriched precious metal bearing particles are generated within the precious metal ore. This might be best understood as similar to dirt being cleaned from rock due to collisions with other rock or walls or sides of the intake, as previously disclosed with respect to landscape rock cleaning. That is, the ore particle collisions include collisions with the entraining airstream boundary (such as, for example, walls or sides of a structure containing and directing the entraining airstream.) Additionally or alternatively, the collisions include collisions between particles being conveyed by the entraining airstream. In either situation, collisions of particles can be effective to enrich, separate, and/or segregate the most economically significant portion of the precious metal ore. That is particles, such as flakes, specs, dust, and small nuggets may be broken free from rock particles within the ore. The separation capabilities of the process, to some extent, are based upon differences in density of the precious metal relative to rock as the particles relatively enriched in precious metal, having higher density, will more easily fall from the reduced or second reduced velocity airstream. Additionally, precious metals such as gold are characterized by substantial malleability (relative to rock) and thus shapes which are less prone to falling from the airstream may be encountered and thus separated and collected after the second reduction in velocity. Those skilled in the art will recognize that the characteristics of various precious metal ores vary widely and thus significant testing may be warranted for any particular ore, in order to determine which level of reduction of velocity more effectively results in enrichment. Using substantial cautions and safety measures, the process may be modeled and or tested by employing a pre-screened rock sample and adding a portion of dense metal particles, such as for example lead shot of different sizes, and observing which velocity reduction(s) provide the optimum recovery of different lead shot sizes. However, it should be recognized that lead is toxic and airborne lead dust might be generated are represent a hazard so appropriate dust handling is essential while performing such modeling or testing. The rock-debris separator chamber 40 previously described for rock cleaning and recovery is a starting point for precious metal ore enrichment, however, velocities and reductions must be adjusted commensurate with the ore and precious metal of interest. The lead shot modeling, described above, contributes to determining more appropriate adjustments. Ultimately, optimal adjustments must be made with the specific precious metal ore to be processed. One of ordinary skill will recognize that the enriched ore may be further processed to extract the precious metal or a still more enriched ore for subsequent extraction by known processes in the precious metal field. It should be further explained that two chambers, such as rock-debris separation chamber 40, may be sequentially arranged with the second chamber receiving a reduced velocity airstream from the first chamber.
In a preferred embodiment, at least one chamber 40 is employed and more preferably, multiple chambers are sequentially employed to provide precious metal ore dry enrichment. Another aspect of this invention is that precious metal ores taken direct from the earth, such as placer samples, as often found in low flow or nearly dry creek beds or dry creek beds, may still include significant moisture on the particles or have particles relatively loosely associated with each other due to residual moisture. The dry process of the present invention tends to advantageously dry or at least reduce the moisture of such samples. This drying effect, in turn, facilitates separation of moisture joined particles into separate particles, thus allowing better air separation or segregation of the most desirable particles, those composed of either entirely or substantially the denser precious metal being collected in the process. The precious metal ore enrichment process is applicable to placer type ores (characterized by being mainly relatively rounded or smooth and pebble-like, such as resulting from creeks or streams), or rock (as earlier defined as any naturally occurring rock or stone, both as is or crushed, typically having a specific gravity of at least 1.25) but with the linear dimension of the particles ranging down to about 0.1 inches.
There may be applications of the present invention where, rather than vacuuming up a stationary mixture of particulates into the intake to provide a mixture of particulates suspended or entrained within the airstream, it may be more practical to transport the mixture of particulates in bulk to the apparatus and then to entrain or suspend the mixture of particulates in the airstream. One such application would be grain or seeds or like materials which are to be cleaned or classified.
As schematically depicted in
As schematically shown in
As depicted in
In view of the preceding description, it may be understood that the present invention process can be applied to variety of useful situations. For example, for many and various industrial processes, the present invention may be employed to pick up, clean up, de-dust, de-stone, size, and/or separate mixtures of granular particulates into a low aerodynamic support fraction of particulates and a high aerodynamic support fraction of particulates. The following list of exemplary applications for the present invention should be viewed as nonlimiting:
Those of ordinary skill will further recognize that various modifications can be made to the present invention without departing from the spirit of the invention.
This application is a continuation-in-part of co-pending U.S. application Ser. No. 12/803,990 filed Jul. 12, 2010 which is a continuation-in-part of U.S. application Ser. No. 12/460,962 filed Jul. 13, 2009, now U.S. Pat. No. 7,867,323, which is a continuation of Ser. No. 11/644,167 filed Dec. 22, 2006, now U.S. Pat. No. 7,559,962, hereby incorporated by reference in its entirety and to which application priority is claimed under 35 U.S.C. §120. This application also claims priority, through the above-mentioned U.S. application Ser. No. 12/803,990, to U.S. provisional applications 61/270,750 and 61/270,758, both filed Jul. 13, 2009, and U.S. provisional application 61/338,308 filed Feb. 17, 2010, all three of which provisional applications are hereby incorporated by reference in their entirety herein.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4166027 | Smith | Aug 1979 | A |
| 5840102 | McCracken | Nov 1998 | A |
| Number | Date | Country |
|---|---|---|
| 2148748 | Jun 1985 | GB |
| 51-081081 | Jul 1976 | JP |
| 51-08108081 | Jul 1976 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20110132814 A1 | Jun 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61270750 | Jul 2009 | US | |
| 61270758 | Jul 2009 | US | |
| 61338308 | Feb 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11644167 | Dec 2006 | US |
| Child | 12460962 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12803990 | Jul 2010 | US |
| Child | 12931825 | US | |
| Parent | 12460962 | Jul 2009 | US |
| Child | 12803990 | US |
