Patent Application
20230007983
This invention generally relates to systems and methods of vacuum excavation, and more particularly to systems and methods for preventing or reducing blockages of spoil material from forming and affecting operation thereof.
The vacuum excavator uses a jet of air to dislodge the soil, rock and other materials, known a spoilage, to be excavated to form a hole or otherwise clear such material from an area. Such vacuum excavation is particularly useful in areas with underground utilities and other structures as it is much less likely to cut or damage such utilities or structures than using hand tools, an auger, or a metal bucket on a backhoe. Indeed, in an operation known as potholing, the specific purpose is to uncover such buried utilities to allow work thereon.
In vacuum excavation a suction hose is used to extract the spoilage in a stream of air. A blower or vacuum pump is used to create the vacuum that pulls the spoilage through the boom. Typical suction pressure utilized in such vacuum excavators range from 0.2 bar to 0.5 bar or roughly 6 inHg to 15 inHg. Larger industrial vacuum excavators may utilize suction pressures as large as 0.95 bar or 28 inHg. Many such vacuum excavators transport the spoilage through the suction hose via a series of bends and conduits into a dis-entrainment system that may include a separation vessel, airlock, cyclones and conveyors, and a discharge pump.
Unfortunately, such typical vacuum excavators that utilize high pressure air to cut the ground, suffer from plugging. Such plugging is also referred to as bridging and is caused by build-up or plugging of spoilage, i.e. soil, rock, and other materials extracted from the excavation site. Such bridging typically occurs in the boom, conduits, and the dis-entrainment system itself. Commonly, once a worker realizes a bridge has formed or is in the process of forming, typically by noticing a weakening in suction power, a club or hammer is used to pound on the boom and conduits in an effort to break up and dislodge the bridge.
Not only does this method of dealing with bridging have the potential to damage the boom and conduits, but it is also inefficient because the worker may not notice the reduction in suction power until the bridge has become well established in at least one, and possibly multiple locations within the boom and conduits. Further, while the mitigation efforts are ongoing, the excavation of the site is halted. Such blockages may also result in overheating of the vacuum pump or blower if allowed to continue for an extended period of time.
Experienced workers may well have a good idea where within the boom and conduits the bridging exists. Such known areas are at sharp bends in the boom and conduits and changes of direction or reductions of spoilage flow, such as at the 90 degree turn area at the back of the debris tank known as the rock head. These areas are particularly troublesome when using air excavation during which a water slurry typical in hydro-excavation is not present to aid in the spoil flow past such areas. That is, unlike a slurry (water and soil) that is extracted during hydro-excavation, dry spoil material cut up with air, especially thick clay, can have problems making this turn and the rock head becomes a point of congestion.
As such, once a blockage has occurred, the experienced worker will often start the pounding in such locations, although there is no guarantee that such focused impacts will be effective if the bridge has formed elsewhere or in multiple locations. As such, the workers are often required to pound along the entire length of the boom and conduits to ensure complete clearance of such spoilage bridges.
Recognizing the efficiency losses that undetected bridging may cause, some manufacturers of vacuum excavators have developed bridging or pluggage sensors that may be added to the vacuum excavator. Various types of sensors may be used in different systems, including weight sensors to measure various locations in the dis-entrainment system to detect the accumulation of spoilage that may indicate the presence of a bridge.
Unfortunately, such sensor systems add additional cost and complexity to the vacuum excavator, which will also affect the excavator's reliability. Further, once the bridging has been detected, mitigation efforts to remove the bridge must still be undertaken. These efforts also impact the efficiency of the system by halting the actual excavation of the site and may require that the vacuum excavator be shut down completely until and unless the bridge can be removed.
In view of the above, there is a need in the art for a vacuum excavator that prevents or reduces the occurrence of a spoilage bridge in the first instance, instead of relying on the detection and mitigation thereof once one or more bridges have formed. Embodiments of the present invention provide such systems and methods for preventing or reducing the occurrence of such spoilage bridges in a vacuum excavator. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.
In view of the above, embodiments of the present invention provide new and improved systems and methods for vacuum excavation to overcome or reduce the occurrence of one or more problems existing in the art. More specifically, embodiments of the present invention provide new and improved systems and methods of vacuum excavation that eliminate or greatly reduce the occurrence of spoilage bridge formation during vacuum excavation.
Even more specifically, embodiments of the present invention provide new and improved systems and methods of vacuum excavation that eliminate or greatly reduce the occurrence of spoilage bridge formation during vacuum excavation, using water or air, and therefore eliminates or greatly reduces the mitigation efforts necessary in prior systems to remove such spoilage bridges from the vacuum excavation system. Such systems and methods thereby greatly increase the operating efficiency and reduce the operating cost of such vacuum excavators.
In one embodiment of the present invention, an air excavator truck utilizing such systems and methods is provided. This embodiment utilizes a single engine that provides operators the ability to excavate with air, water, or both air and water effectively using one truck. In certain embodiments, the water systems are contained within a heated enclosure for cold weather applications. Such an embodiment provides the ability to pothole using a 4″ port, as well as conduct major excavating utilizing a 6″ port. Certain embodiments include payload capacities from 5,000 to 12,000 lbs., and may provide a hydraulic rear door to allow operators to dump spoils quickly and easily.
In certain embodiments, the vacuum pump or blower may be sized to achieve the results needed for a particular application. In preferred embodiments the vacuum pump or blower has a capacity of 18 inHg, while in other preferred embodiments the vacuum pump or blower has a capacity of 27 inHg. Certain embodiments have capacities of 1400 or 3000 CFM, and preferably utilize hose diameters of 6″ or 4″. Certain embodiments utilize a Hibon® VTB series, high vacuum blower, and in certain preferred embodiments, the Hibon® VTB 820.XL blower is used. Embodiments of the present invention also utilize a boom to carry the air flow while providing an operator the ability to dig ten feet below grade.
Preferably, embodiments of the present invention utilize a modular design that allows the use of multiple platforms. In certain embodiments, the system can be mounted on at least two different chassis. In one embodiment, the system is provided on a Class 6 chassis that requires no CDL certification to drive and operate. Such embodiments enable excavation with high pressure air and provide a smaller footprint since there is no need to carry large amounts of water necessary for hydro-excavation. In another embodiment, the system of the present invention mounts on a Class 7 chassis for operators needing increased payload with the ability to hydro-excavate, in addition to digging with air.
In an embodiment of the present invention, truck engine speed has been designed to lower overall RPMs, to consume considerably less fuel than traditional designs, and to reduce operating costs. Such lower RPMs equate to lower noise emissions, which reduces complaints while operating in residential areas. In a preferred embodiment, a silencer package is included to further reduce noise emissions. Such embodiments also provide operators a higher level of safety when they are able to hear each other and the traffic around them during such vacuum excavation.
In one embodiment of the present invention, a vacuum excavator includes a high vacuum blower that is coupled through a multi-stage airflow system having a debris tank to which an excavation hose is coupled. The vacuum excavator also includes a knuckle boom having a first arm segment carrying a first hose roller assembly and a second arm segment carrying a second hose roller assembly. A first angular position relative to horizontal of the first arm segment is controlled by a first actuator, and a second angular position relative to the first arm segment is controlled by a second actuator. In such embodiment the excavation hose is carried by at least one of the first hose roller assembly and the second hose roller assembly. Indeed, at least one of the first arm segment and the second arm segment are angularly positioned by at least one of the first actuator and the second actuator, respectively, to control a flow curvature of the excavation hose from an excavation site to the debris tank.
Preferably, the high vacuum blower provides a suction pressure of 27 inHg. The first actuator controls the first angular position of the first arm segment between approximately 35° above and approximately 35° below horizontal. The second actuator preferably controls the second angular position of the second arm segment between 0° and approximately 100° relative to the first arm segment. This later range also allows for stowage of the knuckle boom during transport.
In an embodiment, the first hose roller assembly includes two sets of rollers spaced along the first arm segment. Each of the two sets of rollers includes two hose contact rollers positioned at an angle relative to one another to support the excavation hose on either side of at least the bottom half of the circumference of the excavation hose. Preferably, the two sets of rollers are spaced along the first arm segment by at least two feet to control a bend radius of the excavation hose therebetween. In a further embodiment, at least one of the two sets of rollers of the first hose roller assembly, and preferably both, includes a third roller positioned horizontally above the two rollers. In an embodiment the two sets of rollers are joined by a support member at the apex of the two rollers of each of the two sets of rollers.
In an embodiment the second hose roller assembly includes two sets of rollers spaced along the second arm segment. Each of the two sets of rollers include two hose contact rollers positioned at an angle relative to one another to support the excavation hose on either side of at least the bottom half of the circumference of the excavation hose. Preferably, the two sets of rollers are spaced along the second arm segment by at least two feet to control a bend radius of the excavation hose therebetween. In a further embodiment at least one of the two sets of rollers of the second hose roller assembly, and preferably both, includes a third roller positioned horizontally above the two rollers. In an embodiment the two sets of rollers are joined by a support member at the apex of the two rollers of each of the two sets of rollers.
In one embodiment the knuckle boom is horizontally rotatable by approximately 180°. In an embodiment the first roller assembly of the first arm segment is positioned approximately 4 feet from the debris tank to which the excavation hose is coupled.
In an embodiment the vacuum excavator includes a high pressure air compressor for providing compressed air to enable air excavation. In another embodiment, the vacuum excavator includes a water storage tank and high pressure water pump for providing high pressure water to enable hydro-excavation. In some embodiments, both are provided.
In an embodiment, the multi-stage airflow system further includes at least one cyclone filter and a final filter positioned between the debris tank and the high vacuum blower. In a preferred embodiment, two cyclone filters are provided.
In an embodiment, a method of reducing the formation of a spoil bridge in an excavation hose of a vacuum excavator includes the steps of providing a high vacuum pressure through a debris tank to the excavation hose to extract spoils from an excavation site, and controlling a flow curvature of the excavation hose from the excavation site to the debris tank to reduce flow disruptions of the spoils extracted therethrough. Preferably, the step of controlling includes angularly positioning a first arm segment carrying a first hose roller assembly and a second arm segment carrying a second hose roller assembly. In this embodiment the excavation hose is carried by at least one of the first hose roller assembly and the second hose roller assembly.
In a preferred embodiment, the step of angularly positioning the first arm segment includes the step of angularly positioning the first arm segment between approximately 35° above and approximately 35° below horizontal. In an embodiment the step of angularly positioning the second arm segment includes the step of angularly positioning the second arm segment between 0° and approximately 100° relative to the first arm segment.
Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Turning now to the drawings, there is illustrated an embodiment of the Vacuum Excavator constructed in accordance with the teachings of the present invention. However, those skilled in the art will recognize from the foregoing and following description and the illustrations to which such is directed that various embodiments beyond those specifically described are within the scope of such teachings. As such, the disclosed embodiments and operating environments should be taken by way of illustration, and not by way of limitation. Indeed, the principles and features discussed with regard to the illustrated embodiments will find benefit in both hydro excavation and air excavation systems regardless of their platform and environment utilization.
Turning now specifically to
While not illustrated, other embodiments may utilize a class 7 chassis that enables operation of both hydro excavation as well as air excavation powered by the single engine of the class 7 chassis. In this embodiment, the vacuum system utilizes a 1400 CFM, 28 inHg, 3600 RPM high vacuum blower, such as the Hibon® VTB 820 XL.
Typically, the smaller platform illustrated in
In order to provide cold-weather operation in cold weather climates, the vacuum excavator 100 also includes a temperature controlled environmental chamber 106 shown in
The vacuum excavator 100 also includes an air tool circuit hose with retractable reel 110, an air hose retractable reel 112, and a water hose retractable reel 114. These reels provide the ability to utilize air tools, as well as to hydro-excavate and air excavate the worksite depending on application.
The debris tank 116, also known as a spoils tank, is accessed via the rear of the vacuum excavator 100 via the hydraulic actuators 118. The entry port 120 to the debris tank 116 is provided in the illustrated embodiment in the upper passenger side of the rear of the debris tank 116.
The vacuum excavator 100 also includes a hydraulic knuckle boom 122 that includes two hydraulic actuators 124 and 126 to control the angular displacement from horizontal of the arm segments 128, 130. The knuckle boom 122 also includes a rotational joint 132 that allows the knuckle boom 122 to be rotated to position the excavation hose (not shown) to and about the excavation site by the user. It is noted that in
As shown in
The vacuum excavator 100 also includes the airflow conduit 150 that delivers the air from the output of the cyclone filters 142, 144 to the final filter 156 before allowing the air to pass through the positive displacement blower. The heat exchanger 154 ensure that the air system operates without overheating.
Once at the excavation site as illustrated in
As may be seen more clearly in
As may also be seen in this
Returning to
The angular displacement of arm segment 130 as controlled by the hydraulic actuator 124 can provide a more significant angular control in view of its location at the end of the knuckle boom 122 which leads to the excavation site. In one embodiment, hydraulic actuator 124 may provide up to approximately 100° of deviation of the arm segment 130 to provide the gradual transition from the excavation site to the entry port 120, and to allow stowage of the knuckle boom for transport.
As will be apparent to those skilled in the art from the foregoing, the combination of the high vacuum pressure and the gradual transition of the excavation hose 158 that leads directly into the debris tank 116 without a change in flow direction eliminates or greatly reduces the occurrence of spoil bridging. This gradual transition of the flow path as controlled by the knuckle boom 122 and its limited angular control of the arm segments 128, 130 ensures that there are no areas of obstruction or significant flow direction changes that can lessen the flow and enable the collection of spoils therein.
Indeed, this high flow and smooth transition from the excavation site to the debris tank 116 that prevents the bridging in the excavation hose 158 is also aided by the three stage airflow sections from entry of the spoils to the debris tank, through material separation and filtering, to the vacuum pump or blower, as will be described with reference now to
Turning then to
The first stage in the airflow system is flow 164 through the excavation hose and directly into the debris tank 116 without redirection of the airflow that can cause or contribute to bridge formation. As the material in the airstream flow 164 enters the debris tank 116 it will start to drop to the bottom of the debris tank 116, and flow 166 is directed toward the front of the debris tank 116 to provide for even distribution therein. The air entering the tank along with the material is routed from the single entry point at the rear of the debris tank 116 to dual exit flows 168, 170 located at each side of the entry flow 164. In this way the air flow is slowed within the debris tank 116 and the material separation is improved.
The second stage of the airflow system takes the air from the debris tank 116 and routes it 172 into dual cyclone filters via flows 174, 176 (shown in this embodiment of the vacuum excavator 100′ on either side thereof). At this point the cyclonic action 178, 180 of these filters propels any remaining material to the sidewalls of the filters and then down into an easily maintained collection box.
In the third stage of the airflow system, the air moves from the cyclone filters via flows 182, 184 into a single final filter as shown by flows 188, 190. This washable filter will capture any fine particles, e.g. down to 10 microns in one embodiment, remaining in the air stream before allowing the air to pass through the positive displacement blower.
All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
