Patent Grant
8393049
1. Field of the Invention (Technical Field)
The present invention relates to a cleaning method and apparatus. Particularly, the present invention relates to a method and apparatus for cleaning a large surface area. No soaps or solvents are required, and a substantial portion of cleaning water is recovered for reuse. Embodiments of the present invention also relate to obstacle clearance and/or recovery systems.
2. Description of Related Art
Note that the following discussion refers to a publication that due to recent publication date is possibly not to be considered as prior art vis-a-vis the present invention. Discussion of such publication herein is given for more complete background and is not to be construed as an admission that such publication is prior art for patentability determination purposes.
Since the U.S. Navy first introduced the aircraft carrier, keeping the large deck area clean has proven challenging and costly. This is particularly true since the various aircraft which use the deck often leak oils, greases, and other fluids onto the deck. This impairs the ability of aircraft to gain proper traction which results in pilots struggling to maintain full control of their aircraft. In response, the Navy has expended vast sums of money and manpower to manually apply soap and water to the deck and then scrub the entire surface with brushes. Since the surface area of the decks of aircraft carriers are very large, substantial amounts of soap are required to clean them. The cost of soap for one aircraft carrier alone can amount to nearly $70,000 per deployment. Further, manually soaping and scrubbing the entire deck of an aircraft carrier impedes the use of the deck by aircraft during the extensive cleaning process, thus resulting in down time for the ship.
While various vehicles are known to be of use for cleaning surfaces, none of the known systems enable a user to continuously recycle virtually all the water used by using solid-liquid and liquid-liquid cyclones as well as strainers and/or a self-flushing filter. U.S. Pat. No. 6,381,801, to Clemons, Sr. describes one such system. The disclosure of that patent, however, is directed to a very large vehicle which relies primarily on filters to achieve water recycling. Those skilled in the art readily recognize that the Clemons, Sr. design is highly susceptible to filter clogging. A system which relies primarily on filters for the purpose of continuous water recycling has the serious drawback of repeatedly requiring a user to remove and clean filters after operation of the vehicle for only short periods of time. As such, the vehicle of Clemons, Sr. not only is inefficient and maintenance prone, but is also a very large and bulky vehicle.
Other cleaning vehicles known in the art are typically very large and must carry two water tanks onboard to sustain operation. A first tank is generally a clean water tank and a second is typically a recovery tank. An embodiment of the present invention eliminates the use of a clean water tank and uses an air-water recovery system.
None of the known prior art vehicles provide a soapless/brushless solution for cleaning large surface areas. Because embodiments of the present invention can recycle the water that is used, discharge regulations which exist for certain areas are more easily complied with. Other embodiments of the invention utilize a brush-membrane system.
There is thus a present need for a mobile cleaning, reclamation, and recycling apparatus that enables a user to recycle virtually all of the water used through the efficient use of cyclones within a compact and mobile unit.
One embodiment of the present invention comprises a mobile cleaning apparatus for cleaning large surface areas. The apparatus preferably comprises one or more wheels, a cleaning head, a vacuum system, and a water processing unit. The water processing unit preferably comprises an air-water separator, a first tank, at least one solid-liquid cyclone, and a filter. The water processing unit can also optionally comprise one or more of the following: an inlet strainer, at least two solid-liquid cyclones and preferably three solid-liquid cyclones, a liquid-liquid cyclone, a decant tank, a float based inlet disposed on the first tank, an evacuating pump disposed downstream of the air-water separator, and a settling tank. The mobile cleaning apparatus of this embodiment can also optionally include a blower, a bulk recovery device, a skimmer, a liquid level sensor, and a pressure gauge.
A cleaning head of an embodiment of the present invention preferably comprises a deck, a nozzle disposed beneath said deck, a brush skirt, an inlet hole, and at least one air/water inlet. The cleaning head can optionally comprise one or more of the following: a separating membrane, a plurality of brushes making up the brush skirt, at least one swivel, at least one flow equalizer port, a vacuum recovery chamber, and a vacuum nozzle for the vacuum recovery chamber. The brush skirt preferably at least partially surrounds the circumference of the deck. The brush skirt also preferably comprises a membrane insert. The cleaning head of this embodiment is preferably capable of obstacle clearance.
Another embodiment of the present invention comprises a method for recycling water used for cleaning large surface areas. The method preferably comprises separating air from liquid constituents and solid constituents collected from cleaning via an air-water separator, separating the solid constituents from the liquid constituents via a solid-liquid cyclone, collecting the liquid constituents in a tank, and filtering the liquid constituents. This method can also optionally comprise one or more of the following: collecting solid constituents in a settling tank, controlling the liquid level control in the air-water separator, maintaining a vacuum separation of the air-water separator, modulating a pump based on the liquid constituent height in the air-water separator, using the filtered liquid constituents for cleaning a large surface area, storing the filter liquid constituents, collecting the solid constituents in a settling tank, passing the liquid constituents through a liquid-liquid cyclone, collecting the liquid constituents from the liquid-liquid cyclone in a decant tank, and straining the solid constituents and liquid constituents after the air-water cyclone.
An advantage of the present invention is that large surfaces are cleaned quickly and efficiently. Embodiments of the present invention relate to cleaning large surface areas by recycling a cleaning fluid such as water. Embodiments of the present invention also relate to obstacle clearing, and solids and liquids recovery.
Cyclone separation provides embodiments of the present invention to run for extended periods of time independent of a volume throughput limitation. Most filters have a limit on the amount of solids or oil that can pass. The onboard recovery/clean water tank design can also improve the space-saving aspects of the invention.
Embodiments of the solid-liquid cyclone can have a plurality of solid-liquid cyclones and an output of one solid-liquid cyclone can be connected in series or in parallel with one or more solid-liquid cyclones. Thus, an output of a one solid-liquid cyclone can be connected to an input of another solid-liquid cyclone in a series configuration or the plurality of solid-liquid cyclones can be connected in a manifold type configuration such that they are in parallel with one another.
If one or more solid-liquid cyclones are used in conjunction with one or more liquid-liquid cyclones, the one or more solid-liquid cyclones can be connected in series with one or more liquid-liquid cyclones. Optionally, one or more solid-liquid cyclones can be connected in parallel with one or more liquid-liquid cyclones.
Embodiments of the present invention relate to methods for cleaning large surface areas. The method includes but is not limited to generating a pressurized flow of water, emitting a spray of pressurized water from one or more rotatably attached nozzles, creating a flow of air around an area of the surface to be cleaned such that at least a substantial amount of the soiled water resulting from the cleaning process is recovered, passing the soiled water through a solid-liquid cyclone, capturing the liquid constituents of the soiled water from the solid-liquid cyclone, and recycling the liquid constituents of the soiled water such that they are again pressurized for re-use in the cleaning process.
The method can include, separately or in combination the following steps: passing the soiled water through a liquid-liquid cyclone, passing the liquid constituents of the solid-liquid cyclone through a liquid-liquid cyclone, passing the liquid constituents of the soiled water through a filter, and/or passing the liquid constituents of the soiled water through a self-flushing filter.
An object of the present invention is to provide a method and apparatus for cleaning one or more surfaces.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or can be learned by practice of the invention. The objects and advantages of the invention can be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:
a, 17b, and 17c illustrate an embodiment of the solids settling tank;
Embodiments of the present invention are directed to methods and apparatuses for rapidly cleaning large surface areas. Particularly, the present invention can be directed to methods and apparatuses for cleaning runways of aircraft carriers with a mobile cleaning vehicle wherein high-pressure water is sprayed onto the surface before being vacuumed up, processed, and reused. Optionally, the present invention can be used to remove dirt, oil, particulates, and rubber buildup from any surface which is driven on. Particularly desirable results can be obtained by using the present invention on runways, including both land-based runways and aircraft carrier runways.
The term “liquid-liquid cyclone” is used interchangeably throughout the specification and claims with the term “liquid-liquid separator”. The term “solid-liquid cyclone” is used interchangeably throughout the specification and claims with the term “solid-liquid separator”. The term “air-water cyclone” is used interchangeably throughout the specification and claims with the term “air-water separator”. The term “brush” as used throughout the specification and claims includes but is not limited to any implement with protruding bristles, or any protrusion allowing for a wiping or brushing motion.
Although the vehicle illustrated in the figures has four wheels, other vehicles capable of transporting the various elements of the present invention can also produce desirable results. The term “wheel” and “wheels” as used through the specification and claims is intended to include any apparatus, device, structure, element, as well as combinations or multiples thereof which can be used to enable a vehicle to travel across a surface, including but not limited to wheels, tracks, treads, rails, etc. Further, although the present invention is primarily directed to cleaning surfaces of aircraft carriers, desirable results can be obtained when the present invention is used on a roadway, parking lot, runway, or other similar structure.
Embodiments of the present invention relate generally to a flat-surface cleaning vehicle which uses high pressure water for cleaning while an onboard cyclone-based system processes reclaimed water and returns it to cleaning service. The union of the cleaning/recovery operations with recycle capability allows the vehicle size to remain small since little water is needed to clean a large area. Although the vehicle can be physically small, the performance (square ft/hr) of the vehicle compares favorably with a much larger vehicle which does not include a recycling feature. The cyclone-based water recycle system of the present invention preferably enables it to recycle recovered wastewater fast enough to permit continuous cleaning with water recycled therewith. The hydrocyclone units are preferably capable of removing solids and oils from the recovered wastewater and returning clean water to the cleaning circuit for re-use. Embodiments of the present invention optionally have cleaning vehicles without a clean water tank compartment.
The recycle unit preferably processes wastewater using two varieties of cyclones. A liquid-liquid (L-L or LL) cyclone removes oil constituents from the wastewater. The L-L circuit preferably ensures removal of oils and greases from the water. The second type of hydrocyclone used is preferably a solid-liquid (S-L or SL) cyclone. This unit preferably removes solid constituents from the wastewater.
One advantage of the present invention is that contaminants recovered during cleaning are contained onboard for appropriate and easy disposal.
Embodiments of the present invention relate to a system and method for cleaning horizontal surfaces that are contaminated with any combination of oils, greases, particulates, and various other material buildups. As such the present invention can be used to remove rubber buildups from runways. Since embodiments of the present invention preferably separate what is sucked into the cleaning system into its constituent components, and since the processed water is reused, embodiments of the present invention can preferably operate for extended periods of time on a single tank of washing water and have the ability to store various contaminants which are recovered from the recycled water.
A system that is flow restricted (i.e. a recycle system cannot keep up) must find other means of achieving cleaning horsepower either by chemical means, hot water or higher pressure. Either way, a flow restricted system increases vehicle complexity. The cyclones of the embodiments of the present invention enable use of a 5-micron filter where competing systems must use 30-microns as final filtration because of operating duration problems related to filter clogging.
In one embodiment, a user fills clean water holding tank 20 prior to use. Vehicle 10 is driven across a surface to be cleaned. Water is pumped from holding tank 20 through high-pressure pump 24 before passing through rotary members 36 and wands 38, whereupon the water is emitted by nozzles 40. Although high-pressure pump 24 is preferably a single large, high volume, high-pressure pump, a plurality of lower volume pumps can be used and will produce desirable results. Vacuum blower 26 preferably vacuums or sucks air, water, and small solid particulates through deck 34. The air, water, and debris sucked into vehicle 10 by blower 26 is preferably passed through strainer assembly 42, where the large solids can be removed. Similar to high-pressure pump 24, blower 26 is preferably a single large high volume blower. Alternatively, desirable results can also be produced with a plurality of lower volume blowers.
Smaller size solids are preferably removed from the recovered water by the use of solid-liquid separator 46, which is preferably powered by centrifugal solid-liquid cyclone pump 48. While various devices and methods, known to those skilled in the art, can be used and will produce desirable results for separating solids from a liquid, a solid-liquid cyclone is preferably employed.
Automatic scanning filter 50 is preferably employed which optionally filters any remaining debris just before the recycled water enters the high-pressure pump.
The vehicle, according to one embodiment of the present invention, can also optionally be fitted with a high pressure hose and wand which is connected to an output of high pressure pump 24 such that a user can manually clean an area with the high pressure wand.
In the event that the present invention loses power, an auxiliary brake release pump is preferably provided that can disable the brakes by pressurizing the brake line so that the unit can be towed by another powered vehicle. Additionally, three or more lift points 52 (see
Referring to the flow chart of
Referring to the flow chart of
The cleaning effectiveness of the present invention is far superior to the prior art with respect to its ability to restore the coefficient of friction on non-skid deck surfaces in less time. Particularly, when embodiments of the present invention are used to clean aircraft carrier decks, numerous benefits can be realized. These benefits include, but are not limited to, 1) quality of life is enhanced for persons who are no longer forced to clean large surface areas by hand with soap; 2) the elimination of soap use for primary deck cleaning enhances the environment; 3) vast reduction in water usage for deck cleaning because water can be re-used by recycling about 16 times per hour; 4) reduction in the use of salt water in spray down leads to less corrosion.
An embodiment of “floating” cleaning deck 35 is illustrated in
The wash water recycle system of the present invention preferably runs in a batch mode of operation rather than continuous. Batch mode functionality offers the longest operating time based on polish filter change out periodicity. This is because the system only produces the processed water in volumes as demanded by the cleaning application. Continuous mode however would offer the ability to “self-clean” the system at the expense of increased consumable use. The mode of recycle (Batch or Continuous) is dependant on post-cleaning activities. If water use and space for waste disposal is at an absolute premium, a continuous system can be used to clean water to a greater degree over time. Since a continuous based system “overproduces” process water more solids and oils are removed. A batch mode justification would be made if the system should operate the longest time between filter maintenance or change out. The invention is capable of and has operated using both methods.
In one embodiment of the present invention, the combined water capacity is approximately 200-600 gallons based on variables in cleaning application. The variables include expected intake of solids and desired square foot productivity rate (corresponds to flow at a given pressure, i.e. the more square footage cleaned, the more nozzles needed to distribute cleaning energy). Oily waste decant tank 70 preferably holds up to approximately 60 gallons of oil waste. As illustrated in
Preferably, with respect to L-L cyclone pump 32, low-shear dual stage progressive-cavity pump 64 is used to retrieve water from onboard water tank 62 by way of floating skimmer 65. Dual stage functionality allows reduced rotational speed and less shear caused on the liquid being pumped. Pump 64 is preferably sized to run continuously during operation of vehicle 10.
Particularly desirable results can be achieved with the pressurized water set to a pressure of approximately 5000 psi at about 15 GPM. This parameter range is desirable because it provides cleaning effectiveness while the components needed to generate such a pressure and flow rate are still relatively small. A positive displacement triplex plunger pressure pump can be used to produce particularly desirable results.
In one embodiment of the present invention, the onboard recycle system should be preventatively maintained by removing solid and oil waste from the vehicle. The separate solid-liquid and liquid-liquid cyclone systems preferably denote the two separate offloading requirements for the vehicle after a cleaning cycle has been completed. The oil waste is preferably contained in the “decant” tank 70 where a hose can be connected for offloading into the oily waste holding tank (e.g. on a ship). The solid waste is contained in the S-L cyclone “grit-pot” 78 and is retrieved by a detachable grit pot (assuming another is on hand) or a bucket container put in position (below the grit pot) while a ¼ turn valve is turned. The slurry tank is also optionally equipped as a self-dumping hopper in applications where large volumes of solids are expected. This is applicable in municipal and airport environments or where large volumes of solids are encountered. The solids system is also equipped with clean out jets and a pumped system to aid in effective solids slurry offload.
The pressure cleaning and recycle system are preferably activated and deactivated via a single switch. The switch actuates vacuum blower 26 and rotary members 36. A clearly visible two state indication lamp is preferably used for operation status of rotary members 36. In the event of stop-standing, the operator is preferably trained to recognize that the unit is actuated and it is thus necessary to switch the cleaning system off. The foregoing invention can also optionally include a simple interlock system that uses the vehicle travel speed to determine the operation status of the cleaning/recycle system. The mechanism can be a simple gate logic circuit where the pressure system can be operated when the vehicle is traveling greater than a predetermined speed and the switch is in the on position. Systems equipped with a higher power per square foot capability (IE rubber removal, paint removal) may have an interlock built in due to the damage possibility being higher than that of a machine designed just for cleaning in a municipal or street environment.
The use of a cyclone permits a very large amount of solids and oil to be processed without attention to the cyclone devices, as would be the case if a filter were used. The cyclone method of separating solids and oil from recovered wash water is effective and is preferably a component in the wash water recycle system. Water quality results illustrate that the levels of oil and solids in treated water using cyclones are close to acceptable discharge and recycle levels. A fine “polishing” stage self-flushing filter is preferably incorporated into the apparatus. The advantage to the system is that the final stage filter is singular in size and number of units because the cyclone is acting as primary staged filtration in advance of the polish filter. The particle size distribution of influent immediately before the final filter is similar to influent after a bank of filters successively sized. This results in the ability to use a single filter element (self flushing and non self flushing) in its desired final size. In this case the filter is generally sized at 5-microns.
In one embodiment, brush skirt 142 (
Embodiments of the present invention preferably have a number of different capabilities. For example, an embodiment of the invention preferably performs both duties of a cleaning deck including but not limited to containment and recovery of solids and liquids while retaining the ability to clear surface obstacles or protrusions. The present invention optionally uses internal-to-the-deck flow-equalizer ports 143 and 143′ to balance containment and recovery functions without excessive need for vacuum blower power. Flow equalizer ports 143 and 143′ allow for effective containment functionality without passing excessive flow between brush skirts 142 (
The embodiment of the present invention comprising brush shirt 142 and sprayers/nozzles 134 preferably allows effective solids and liquid recovery from a flat surface by virtue of extending the water/solids entraining air flow as close to the surface as possible without excessive pressure drop. This recovery functionality is common to vacuum applications however, the extended brush nozzle system provides this recovery performance while allowing for excellent obstacle clearance. Surface cleaning deck 130 provides a plurality of functionalities, including but not limited to separate functionalities. A functionality of the embodiment can be cleaning fluid containment. Deck 130 preferably contains the majority of sprayed water and resulting spray bounce. Alternatively or in conjunction with cleaning fluid containment, deck 130 recovers cleaning liquid and produced solids on the surface. This embodiment can optionally use pressure/flow equalizing ports 143 and 143′ to allow both functions to be served by apportioning needed containment flow through internal-to-the-deck equalizing ports 143 and 143′ and by feeding vacuum nozzle 144 with adequate flow to produce air/water entrainment especially along the brush line in front of separating membrane 138. This functionality is preferable if vacuum nozzle 144 is a non-positive displacement type unit that is performance hindered if excessive back pressures are found in cleaning deck 130 (
Referring to
The addition of membrane 138 between brushes 140 extends approximately 1 to 1¾″, such that it is approximately ⅜″-1″ short of contacting cleaning surface 132, forms an air inlet to brushes 140 directing the majority of air underneath, thus efficiently using the vacuum flow and pressure directly on the work.
Optionally, the embodiment can have strainer 152, which is positioned before pump 153, thereby reducing pump wear by allowing settleable solids to drop into a waste container before they can reach the general recycle module.
Alternatively, L-L 158 and the decant portion of decant/stage 2 tank 160 can be deleted. In this embodiment, pump 159 remains and provides power to the S-L cyclone circuit. A float based inlet in Stage 1 tank 156 prevents oil transfer to the rest of the system. In this embodiment, the oil would remain in Stage 1 tank 156 and the float based inlet has an unconventional function. The float based inlet is preferably attached to an inlet (to feed pump 159) underneath the surface approximately 2″-10″ so as to always draw water from stage 1 tank 156 beneath the presumable oil level.
This recycle system reduces complexity and avoids over-processing of water through final filter 172. This arrangement improves the final filter life by 20-30% because only water used by high pressure pump 24 is filtered, unlike known systems which must overproduce to keep up with demand. A non-positive displacement pump can be used in this case.
Inlet cyclone (S-L 1) 154 can be added to progressively categorize solids in separate waste streams, (for example coarse, easily-dewatered, solid waste other downstream cyclones optionally protect final filter 172 from a wide range of fine solids that tend to cause premature failure in polishing filters). Inlet cyclone (S-L 1) 154 (
As illustrated in the embodiment of
Run-dry functionality can be used as a method that allows for water level control in air-water separator 150 (see
An alternative system is illustrated in the flow diagram in
Skimmer 157 preferably floats on top of the water level in stage 1 tank 156 and uses a diversified flow technique that draws water from the surface and from the sub-surface. This functions as an oil-surge protector so that LL-1158 is not overwhelmed with oil content in the case of a surge of oil introduced into vehicle 10. The surge protection prevents oil concentrations input to LL-1168 feed from being too high. In a case where LL-1158 is overwhelmed it rejects oil from the overflow (normal operation) and the underflow, thus contaminating the downstream process.
This embodiment allows for optionally eliminating the clean water tank from the process. By using a centrifugal or other non-positive displacement pump at stage 2160, water can be fed on demand through the polish filter to the high pressure pump. This on-demand functionality simplifies the overall tank design as well as reduces the overall amount of water needed to go through final filter 172. This functionality can increase the vehicle run time between polish filter change outs by up to approximately 30% compared with an overproducing type system that fills a clean water tank which then overflows back to stage 2 tank 160 or stage 1166 (see
Embodiments of the present invention include solids settling tank 170 that has technology to “self-clean” for gross solids offload whereas other tanks in the system are not equipped with this ability to self-clean. Solids settling tank 170 is the end point for the fines-processing cyclones. The end goal of solids settling tank 170 is to reduce disposal footprint: solids are as concentrated as possible with as little liquid component in a solids offload and post-solids offload management scenario. The concept of solids settling tank 170 is that solids-liquid waste can be segregated to a single container (e.g. a 55-gal drum) and the remainder of the waste in the vehicle is largely liquid waste. Solids settling tank 170 is designed to handle solids buildup whereas buildup in other tanks would produce extra mucking-out work and disposal footprint. Tank 170 preferably uses pump-produced slurry jets (not shown) to agitate the area immediate to tank exit hole 171.
Referring to
Embodiments of the present invention preferably comprise an air-water separator that can be used in a recycle system as illustrated in
Air-water separator 178 preferably comprises air-liquid/solid inlet 180, liquid/solid pump-out plus vacuum isolation port 182, air exit port 184, and cyclone apex cone 186. Air-water separator 178 can use a closed underflow which isolates the vacuum from the rest of the system. Vacuum isolation port 182 can allow for flexibility in water-tank construction and reduces the criticality of fluctuating water levels relative to dewatering functionality. The closed underflow configuration preferably includes level sensing technology and a pump interface to remove liquid and solids material. The pump can be attached to a control loop with the level sensing technology to “keep up” with the increasing liquid level as water and solids are ingested. An optional solids storage and removal drum (or coarse solids handling bag) can be added to air-water separator 178 to enhance the coarse solids handling of the system. The drum attaches below air-water separator 178 and fills with water initially and as solids are ingested in the system, the solids displace the water up to the drum's capacity (roughly from 5-40 gallons). This feature would be selected for systems that see a large intake of solids thus having the need to remove dewatered solids in larger format than inlet strainer 152 (
One embodiment of the present invention comprises an optional bulk recovery device that can be used in conjunction with water-based cleaning to accomplish bulk waste cleaning and recovery. Water based surface cleaning vehicles are generally effective in recovering a wide range of material. The recovered material can range from fine solids to bulk coarse solids and Liquids in varying volumes. Large volumes of waste and bulk materials are not usually compatible with liquid based waste management and storage commonly associated with water based vehicles. The recovered bulk material usually requires secondary handling or separation at the end of a cleaning mission. Separation or classification of this waste material is essential to cost effective waste management.
The bulk recovery device in conjunction with a water based cleaning system can do the following:
The optional bulk recovery device preferably achieves much of the bulk cleaning needs without stressing the waste management weaknesses of a water-only based system. A novel integration of the “Dry-Cycle” (bulk recovery) and “Wet-Cycle” (water-based cleaning system) is accomplished by using a single blower and routing the incoming “Dry Cycle” blower exhaust to Wet Cycle air-water separator 178. This unique integration not only relieves the separate bulk and liquid waste management issues, it also addresses a common weakness in Water-Free systems. This weakness involves reintroducing small solid particulates into the atmosphere via vacuum blower exhaust. There are many systems that use varied means of reducing the particle pollution. Filters, air regeneration, and water spray down are common methods to suppress dust generated during Dry-Cycle recovery. The Dry-Wet system allows for bulk liquid and solid recovery while affording dust suppression attributes already associated with water-based recovery.
As described more fully in the Examples below,
The invention is further illustrated by the following non-limiting examples.
By way of example, the following is provided to describe in greater detail a preferred embodiment of the present invention:
Although all components are not required, an embodiment according to the present invention, was constructed with the following characteristics, included: an integrated cleaning-recovery and wash water recycle system; a 10,000 ft2 per hour-25,000 ft2 per hour cleaning productivity rate; a 6 foot wide integral cleaning head; four wheel steering with selectable 2 wheel steering mode; a 11.6 inch 4-wheel steering turning radius (outer wheels); a hydrostatic drive mechanism capable of variable speeds from 0.4 to 5 mph; a single 126 hp diesel engine; a remote pressure washing attachment for manual touch-up cleaning; 10-12 inches ground clearance; 60 inches overall height; and several safety features including but not limited to “Dead-Man” pedal and automatic brake with the loss of hydraulic pressure, secured fasteners, hand operated parking brake, towable after primary power failure, low chassis tie-downs, lift points, foam filled tires, weight placard, and center of gravity marked.
The constructed vehicle was powered by a diesel engine. The engine produced continuous horsepower (e.g. 126 hp) and ran a primary hydraulic pump which in turn operated vehicle mobility and steering. The engine provided direct drive rotational power to the primary water cleaning pump. The engine was accessorized with a secondary hydraulic pump that powered two circulating pump motors and the vacuum recovery blower.
The engine selected was a 140 hp at 2400 rpm intermittent, 126 hp at 2400 rpm continuous use with a, peak torque of 367 ft lbs at 1400 rpm, Tier III compliance as required by US EPA for all certified engines, emission requirements met without degradation of engine performances or power level; quick engine change capable, and a 24 volt electrical system.
The vehicle chassis was based on a fusion-welded reinforced ladder bar frame design using, e.g. ASTM A500 Grade A or B rectangular tube, plate, and some common structural shapes. An epoxy or polyester thermoset powder coat finish was applied.
The vehicle that was built included identical front and rear axle/steering suspension components, all wheel hubs preferably had the same bolt pattern so all four wheels were interchangeable, hydrostatic differential steering with conventional steering wheel control, the frame had four low chassis tie down points; four lift points, (no spreader bar was needed), compact planetary gear reduction wheel drive with integral variable speed hydraulic motor and the steering-braking systems were in an isolated circuit.
After construction, the vehicle was tested. However, before testing of the cleaning effectiveness was attempted, a study of available nozzle types was done. The nozzle types surveyed included standard 0-80 degree 1-piece metallic nozzles to multiple component (single head) designs that incorporate a spinning mechanism. Several proprietary designs were examined that did purport performance beyond typical single piece nozzles. The cost and reliability issues of these rotating nozzle types were weighed against their adoption.
The deck width of six feet and a goal of 10,000 ft2 per hour cleaning rate dictated a forward travel speed of approximately 0.4 miles per hour. This speed range was used to qualify the cleaning requirements and rotating nozzle design. An approximate 2 inch stand off distance was found to avoid contact between the rotating nozzle head and any deck level obstructions which were likely to be encountered on a deck of an aircraft carrier. When practically possible, the standoff distance was reduced due to impingement effectiveness being higher with less distance. However, 2 inches achieved acceptable performance. Measurements taken illustrated a maximum clearance of 1.75 inch and a ¼ inch margin of safety was added for a total of 2 inches.
A positive displacement pump was selected due to maintenance advantages compared with other types of pumps. The factors considered were: maintenance issues such as packing type and seal composition, water quality requirements, location of manufacture in regards to spare parts availability, and the actual size of the pump versus the pressure and flow rate capabilities.
The largest challenge in selecting a pump was in the form factor of the actual pump. The pressure and flow range generally dictated that the pumps were outside the “water blasting” market. Numerous manufacturers offer triplex positive displacement pumps in the parameter range selected. Pumps were selected based on strong maintenance advantages and seal composition compared with other pumps. A stainless steel “liquid-end” and low-seal-wear ceramic plungers were also a factor. Seals with solid EPM were selected to provide desirable results. Valves in the unit were expected to operate for 3000 hrs. Basic energy calculations were made based on 5000 psi and 15 gpm in order to determine the effects of water recycling. The calculations yielded 55° F. temperature rise in one hour. This level did not require a heat exchanger in order to protect pumping or delivery equipment.
A 2 inch high spray bar (nozzle tip-surface) and 40 degree nozzle tips required 50 nozzles to be used in order to cover a six foot wide spray path.
During testing, a single spray nozzle at equivalent standoff distances fared poorly compared with a rotating head surface cleaner. The rotating spray bar, by use of standard nozzle tips and a singular rotating swivel, is used in a majority of industrial cleaning applications. Only rotating spray bar designs were used. Testing was conducted using lower pressures and a rotating head surface cleaner.
A thorough study of hydrocyclone effectiveness in various configurations was performed. In one embodiment, a single U2-gMAX 3020 S-L urethane cyclone was found to produce particularly desirable results and was specified to meet throughput requirements which were set at approximately 15 gpm. Desirable results were also produced by using two smaller L40-gMAX L-L cyclones in parallel. A single pump fed both cyclones and inlet and outlet connections were shared.
The cleaning effectiveness of the present invention was tested on a surface with a non-skid coating. A pressure range of 3000 psi-10,000 psi was tested on a soiled plate of nonskid. 0-15 degree nozzle tips were used with varied flow rates within the nozzle type. A stand alone 15 degree fan spray nozzle tip running at 4000 psi using 2.5 GPM was tested with success. This was followed by testing a rotating spray bar assembly using the standalone resulting parameters. The rotating spray bar performed well at the higher 0.79 mph travel speed. Testing revealed that a shorter standoff distance improved cleaning performance. Dual travel speed settings were tested to simulate a “restoration” cleaning and maintaining cleaning parameter set. It was found that 0 degree tips provided the best impingement but the least in coverage efficiency. Fifteen degree tips provided a practical best between impingement and coverage.
Vehicle travel speed, stand-off distance and water pressure/flow rate were significant variables during testing. The water pressure and flow rate determined the rotation speed in revolutions per minute (RPM) of the cleaning swivel arms. The resultant RPM produced acceptable cleaning results by angling the nozzles to rotate the swivel assembly. The non-powered RPM can be adjusted slightly by varying the relative angle of the nozzles. While adequate cleaning was accomplished with self-rotating swivels, both powered-rotation and self-rotating swivels are useful in accordance with the present invention. The swivel assemblies specified were capable of operating with both powered and self-powered modes. A powered assembly allowed greater nozzle impingement by angling nozzles perpendicular to the deck surface. A Hall-Effect rotation sensor was used to determine spinner RPM. The spinning information is used to prevent spinner over speed conditions and to detect possible nozzle clogging which can result in lower or no RPM. The on-board computer alerts the operator if the spinners are over sped or if there is a possible clogged nozzle.
By using a six foot cleaning path, several possible combinations of rotor placement exist. A two rotor design and a three rotor design were useful due to a flow rate capacity of 15 GPM. The figures below illustrate striation placement “striping” of the cleaning path at travel speeds that corresponded to 10,000 ft2/Hr and 25,000 ft2/Hr cleaning rates.
The test concluded that there were no spaces larger than two inches as gaps. The corresponding fan spray width at 1.9 inches was two inches in width.
In another test, a non-skid surface was soiled. The surface was cleaned at various travel speeds and pressures. Only pressures up to 3500 psi were tested. A rotating head surface cleaning device was used for testing. A single fan tip was compared with the rotating spray arm method of cleaning. The non-skid was sent to a supplier for cleaning testing. The supplier used an ultra high pressure positive displacement pump in conjunction with a pressure regulating mechanism to produce various pressures for surface cleaning. A zero degree rotating spray bar nozzle tip assembly combined with vacuum recovery was evaluated.
In yet another test, pressure range of 4000-10,000 psi was evaluated. A positive displacement pressure pump combined with the water swivel for rotating spray bars was found to be effective. The tested cyclone unit was rated at 15 GPM flow rate.
In order to establish realistic testing conditions, results were obtained that show solid and oil concentrations from a sample aircraft carrier cleaning. Tests were performed and a test plan was formulated that called for a Liquid-Liquid (de-oiler) cyclone and a Solid-Liquid cyclone separately. The following conditions were used to develop a test plan that was executed. Test plan assumptions included but were not limited to: influent composition of (i) sample solid content of 7130 mg/l (median); (ii) sample oil/grease content of 1173 mg/l (median); and 1:1 ppm.
In the example, oil composition was an equal mixture containing diesel fuel, hydraulic oil and way oil. Table 1 below shows a relationship between “slugs” (oil concentration that was added to main tank) and samples taken from the “underflow” (L-L cyclone processed water port). The concentrations, as shown below, were calculated: 200 ml oil concentrate plus 300 ml water plus 1000 ml water recovered. The sample was taken 1 to 2 seconds after the mixture was added directly into the skimmer (at ˜60 l/m flow rate). One liter of additional water was added into the mixture: 200 ml oil plus 1300 ml water which resulted in a 133,000 ppm oil concentration.
Samples were added to the sump with minor agitation. The samples were not fully diluted with the sump water. As a result, the intake concentration (at skimmer) was much higher than the calculated concentration that accounted for the entire fluid volume.
Sample 2 was unique due to the oil concentrate being added directly into the skimmer. The sample was taken immediately after the slug was added. The lab results returned the lowest measurement of the lot. This can be explained by virtue of the sample concentrate containing less segregated oil droplets. The relationship between oil droplet size and recovery rate is illustrated in the L-L cyclone settings.
Test results ranged from 44-93 mg/l. The similar values of the ranges tended to indicate that soluble constituents were present in the overflow. The removal of the free product (mixture
The composition of the test sample solids (as determined by slug composition) were slug 1: low specific gravity coarse sample comprising IX Resin with a specific gravity of 1.2-1.4; slug 2: fine particulate comprising paint chips, sand and ground dirt, and used sand blast media combined with larger particles as found in sample 1; and slug 3: very fine particulate comprising IX resin S.G. 1.2-1.4<10 μm.
The preceding examples can be repeated with similar success by substituting the generically or specifically described operating conditions of this invention for those used in the preceding examples.
Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above and/or in the attachments, and of the corresponding application(s), are hereby incorporated by reference.
This application is a continuation-in-part application of U.S. patent application Ser. No. 11/301,462, entitled “Surface Cleaning Vehicle”, to Hans E. Vogel, filed on Dec. 12, 2005, and the specification and claims thereof are incorporated herein by reference. This application also claims priority to and the benefit of the filing of U.S. Provisional Patent Application Ser. No. 61/176,023, entitled “Surface Cleaning Vehicle”, filed on May 6, 2009, and the specification thereof is incorporated herein by reference.
The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of Contract No. N00014-02-M-0176 awarded by the U.S. Navy.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3870489 | Shaddock | Mar 1975 | A |
| 4325901 | Holding et al. | Apr 1982 | A |
| 4586208 | Trevarthen | May 1986 | A |
| 4696075 | Grave | Sep 1987 | A |
| 5228623 | Raghavan et al. | Jul 1993 | A |
| 5287589 | Hughes | Feb 1994 | A |
| 5404613 | Whyte | Apr 1995 | A |
| 5407584 | Broussard | Apr 1995 | A |
| 5444892 | Ris et al. | Aug 1995 | A |
| 5659923 | Coombs | Aug 1997 | A |
| 5826298 | Rohrbacher et al. | Oct 1998 | A |
| 5947300 | Lange | Sep 1999 | A |
| 5970574 | Thrash, Jr. | Oct 1999 | A |
| 5991968 | Moll et al. | Nov 1999 | A |
| 6017400 | Clark et al. | Jan 2000 | A |
| 6129094 | Moll et al. | Oct 2000 | A |
| 6161250 | Young et al. | Dec 2000 | A |
| 6206980 | Robinson | Mar 2001 | B1 |
| RE37162 | Roden | May 2001 | E |
| 6302967 | Rohrbacher et al. | Oct 2001 | B1 |
| 6370728 | Burns | Apr 2002 | B1 |
| 6378163 | Moll et al. | Apr 2002 | B1 |
| 6381801 | Clemons | May 2002 | B1 |
| 6481448 | Mathieu | Nov 2002 | B2 |
| 6536067 | Truan et al. | Mar 2003 | B1 |
| 6675437 | York | Jan 2004 | B1 |
| 6896742 | Geyer et al. | May 2005 | B2 |
| RE39422 | Clemons | Dec 2006 | E |
| 7171722 | Keller | Feb 2007 | B2 |
| 7290307 | Chao | Nov 2007 | B1 |
| 7735186 | Vogel | Jun 2010 | B1 |
| 7770254 | Alexander | Aug 2010 | B2 |
| 20020002985 | Mathieu | Jan 2002 | A1 |
| 20020178529 | Geyer et al. | Dec 2002 | A1 |
| 20030037805 | Mathieu | Feb 2003 | A1 |
| 20050198752 | McGraw | Sep 2005 | A1 |
| 20050210623 | Buckner | Sep 2005 | A1 |
| 20100068042 | Bruck et al. | Mar 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 10-0755581 | Sep 2007 | KR |
| WO02097197 | Dec 2002 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20100269860 A1 | Oct 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61176023 | May 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11301462 | Dec 2005 | US |
| Child | 12775279 | US |
