Abstract:
A system for removing paint and other coatings from hard surfaces is mounted on a truck for over-the-road travel. The truck bed carries a high power vacuum pump, a self propelled tractor with an attached blast head, a liquid reservoir, a sump or vacuum tank, and a ramp for loading the tractor. The reservoir is connected to a low pressure pump that transfers water to the high pressure pump. The high pressure pump is connected to the blast head by a high pressure hose. A vacuum hose is connected to the sump which has an internal enclosure for separating the waste materials from the liquid for easy dumping of semi dried materials.

Description:
FIELD OF THE INVENTION 
   This invention relates to the field of high pressure water cleaning devices for highways, runways, parking decks, and other hard surfaces. 
   PRIOR ART BACKGROUND 
   The use of paint stripes on road surfaces is the accepted method to indicate vehicle lanes, crossing lanes, parking areas and numerous other indicators. Various pavement marking techniques are known, including the use of traffic paint, thermoplastic, epoxy paint and preformed tapes. Common pavement surfaces are asphalt and concrete. Most pavement marking systems are intended to be as durable and permanent as possible, and resistant to weathering and wear from traffic. The removal of such striping is typically required when the road is to be resurfaced or if the indication is to be changed. The removal of such stripes is typically performed by use of abrasive wheels, grinding teeth, or the blasting of abrasive particles against the material to be removed. The use of these carbide teeth and grinding wheels results in an undesirable trench or groove in the road. 
   For example, paint, when used for roadway marking, penetrates into the pavement, perhaps ⅛-⅜ inch, so that mere surface removal of the paint is not sufficient to remove the marking. For example, a pavement marking removal technique that uses abrasive wheels or teeth can create excessive heat which may be suitable for removing painted markings but can melt thermoplastic materials causing equipment to gum up, by reconstituting the thermoplastic. 
   Current pavement marking removal machines typically employ various forms of cutting devices to remove the marking material, as well as a portion of the underlying layer of pavement material, for example, ⅛-⅜ inch, in order to effectively remove painted lines, including paint which has penetrated the porous pavement. A common type of machine employed for removing pavement marking is known as a “Road Pro” grinder manufactured by Dickson Industries, Inc., in Dickson U.S. Pat. No. 5,236,278. This type of machine employs parallel passive shafts that extend between circular rotating end plates. Hardened steel star wheels are carried on the parallel passive shafts, and these star wheels strike and abrade the pavement surface. 
   Another approach to pavement marking removal is the use of diamond saw blades arranged to make a dado cut. Still other types of machines use grinders or shot blast as described in Patent Registrations U.S. Pat. Nos. 4,753,052; 4,376,358; 3,900,969; 4,336,671; 3,977,128 and 4,377,924. 
   NLB Corporation markets a high pressure water jet system for removing paint from pavement under the name “StarJet”. The water jet system includes a blast head frame mounted on an attachment to the front bumper of a prime-mover truck. Casters support the frame for movement over the pavement and the path of the blast head is controlled by the driver steering the truck. Because of the position of the driver and the cab body of the prime-mover, it is difficult to see the blast head&#39;s position with regard to the stripes on the pavement. Any vision at all requires the driver to lean out of the driver&#39;s side window resulting in fatigue and other non ergonomically efficient factors. Positioning the head to the passenger side is performed manually with some difficulty and greatly complicating the driver&#39;s ability to view the blast path. The driver must now position himself in an almost upright standing position. Further, due to the length of the extension holding the blast head, the angular off-set, and the swivel of the casters, the movement of the wheel of the truck is not directly related to the path of the blast head. 
   NLB Corporation also has another system marketed under the mark “StripeJet”, that is a self propelled tractor with a blast head on the front of the tractor. The blast head has a shroud and high pressure inlet with a vacuum recovery. 
   Another stripe removal system is marketed by the Blasters Corporation which is mounted on a truck similar to the “StarJet” device. Another model appears to be a self-powered four wheeled tractor, similar to a grass mower, which supports a driver and is connected to the prime-mover by high pressure lines for delivery of high pressure water to a blast head. The blast head is on the front of the tractor. 
   The problem with the prior art is the inability to place an operator close to the material removal site by use of a device that has over-all dimensions that allow for easy transfer sideways on a truck or trailer having a width less than 8′6″. 
   SUMMARY OF THE PRESENT INVENTION 
   Briefly, disclosed is a cleaning system for removing coatings from a hard surface by high pressure liquid. The system employs a liquid reservoir connected to a high pressure pump for directing ultra high pressure water through a blast head mounted on a self-propelled mobile frame. The mobile frame is a self-propelled tractor wherein the blast head and tractor are of a size for removably docking transversely on a bed of said truck. The cleaning system is mounted on the truck or pulled behind the truck on a trailer. The truck is then tethered to the tractor during operation. The truck bed includes a ramp sized to support the tractor for docking and transport. 
   It is an object of this invention to provide a vacuum recovery truck mounted stripe removal system having a compact unit for safe, fast over-the-road travel to job sites. 
   It is another object of this invention to provide a unit that is quickly deployed, with hoses not having to be disconnected, and in operation at the job site. 
   It is a further object of this invention to provide a tractor mounted blast head that is hydraulically articulated from left to right and at the same time when moved all the way to the right this also brings the blast head closer to the wheels of the tractor thereby reducing its overall dimension to under 8′6″ when in its upright and locked position to reduce the over-all dimensions of the blast head for over-the-road transportation. 
   It is still another object of this invention to provide a blast head that is articulated to swing horizontally independently of the tractor path for more flexibility in coverage. 
   It is a further object of this invention to provide a high pressure water jet for removal of paint or other coverings and a vacuum recovery system for the water and debris being generated. 
   It is yet another object of this invention to provide a collection/filter receptacle for the removed materials for ease of disposal and the release of filtered wastewater. This allows an operator to easily regain all of the available capacity not occupied by paint chips or road debris of the vacuum chamber by simply releasing the dump valve. All of the remaining debris is retained until such time as the vacuum chamber is completely full of actual debris. The amount of capacity able to be regained will be continually diminished as the vacuum tank fills with debris and will eventually reach a point of inefficiency at which point it must be dumped. When the material is dumped, it is dumping semi dried, dewatered debris in which the wastewater is not mixed with the debris. 
   Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     While the novel features of the invention are set forth with particularity in the appended claims, the invention, both as to organization and content, will be better understood and appreciated from the following detailed description, taken in conjunction with the drawings, in which: 
       FIG. 1  is a side view of the stripe removal system; 
       FIG. 2  is a perspective of the stripe removal system with blast head deployed; 
       FIG. 3  is a front view of the blast head and tractor; 
       FIG. 4  is perspective of the blast head link; 
       FIG. 5  is a side view of the tractor with blast head stowed; 
       FIG. 6  is a side view of the liquid reservoir and sump; and 
       FIG. 7  is a perspective of the sump and waste removal system. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The paint removal system  10 , shown in  FIG. 1 , includes a prime-mover truck  11  and a trailer  17 . The truck has a forward cab-over  18  for the driving controls and operator. Mounted on the bed  12  of the truck is the water reservoir  13  and the sump  14  or vacuum chamber. The reservoir and sump are interconnected by a strategically positioned duct for continuous dumping of filtered wastewater when operating from a fixed position where liquid is supplied to the high pressure pump by a means other than the reservoir  13 . 
   The sump  14  is positioned on the rear end of the bed  12 . The rear portion  91  of the bed is pivotally mounted on the truck frame and hydraulicly powered to move in the vertical plane permitting dumping of the contents of the sump  14 . The sump  14  is connected to the vacuum pump  15  by hose  16 . The intake of a high power vacuum pump capable of approximately 1100 CFM (cubic feet per minute) is connected to the vacuum tank. The vacuum tank and pump are also mounted on the bed of the prime-mover  11 . 
   A ramp  19  is hinged to the edge of the bed  12  between the vacuum pump  15  and the cab  18 . The ramp can be lowered to provide a pathway for the self propelled tractor  20 . As shown, the ramp  19  is in the stowed or traveling position for highway transport. When the ramp is unfolded it is approximately 9 feet in length. 
   The trailer  17  is removably attached to the prime-mover through a conventional trailer hitch. Mounted on the bed  22  of the trailer is a high pressure fluid pump greater than 25,000-40,000 psi and from 2-15 gallons per minute. A high pressure hose connects the pump with the blast head during operations. 
   In  FIG. 2  the mobile tractor  20  is illustrated in the normal operations position. The tractor is similar to a riding mower with a small engine self propelling the tractor. The blast head  23  has at least one and up to sixteen high pressure nozzles  69  delivering high pressure fluid to the surface to be cleaned. The high pressure nozzle is carried on a chassis  24  mounted on casters  25 . A shroud  27  descends from the chassis and surrounds the high pressure nozzle. The blast head is connected to the high pressure hose by line  26  and the shroud  27  is connected to the sump by waste removal hose  28 . The high pressure hose  26  and the vacuum hose  28  is supported by a swinging boom  29  which is mounted on the prime mower  11  shown in  FIG. 1  to provide freedom of movement for the tractor and to prevent tangling or running over of the hoses by the prime mover. 
   As shown in  FIGS. 3-5 , the blast head  23  is connected to the tractor  20  by an articulated link  31  which is capable of horizontal movement, as shown in  FIGS. 3 and 4 , and vertical movement, as shown in  FIG. 5 . A bar  32  is attached to the tractor frame by rods  33  and  34 . The bar  32  is located between the front wheels of the tractor. The horizontal swinging movement of the link results in a widened path of the high pressure nozzle to adjust for different widths or patterns of striping of the surface being cleaned and deviations in direction of the tractor. The horizontal movement is powered by the hydraulic cylinder  35  connected to bar  32  which may be controlled by the operator moving a joy stick on the tractor. As the hydraulic piston  36 , connected to the trailing arm  37 , arm  37  and  38  move, with the trailing arms rotating about pins  39  and  40  attached by brackets  41  and  42  on bar  32 . 
   The forward end of the articulated link  31  has a plate  43  connected to the forward ends of trailing arms  37  and  38 . The arms  37  and  38  are rotatably connected to the plate by brackets  41 ′ holding pins  39 ′ respectively. The forward arms  44  and  45  are rotatably connected to the plate  43  to rotate vertically. Pins  46  and  47  extend horizontally through brackets  48  and  49 . Another hydraulic cylinder  50  is connected to the plate  43  and the piston  51  is connected to the forward end of the arm  44 . As the piston  51  moves, the distance between the to be cleaned and the blast head  23  changes. The vertical movement permits elevation changes to accommodate the contours of the surface. Further, the blast head  23  may be raised to the vertical position and then manually flipped up and back reducing the overall length to permit the tractor  20  and blast head  23  to be stowed on a truck bed sideways consuming a space less than 8′6″ for highway travel, shown in  FIG. 5 . The forward ends of the arm  44  and  45  are attached by pins  52  and  53  to brackets  54  and  55  to prevent binding as the arms are manipulated. The brackets are mounted on blast head attachment plate  56 . 
   A blast head attachment plate  56  is removably connected to the chassis  24  of the blast head  23  to provide support and control of the blast head from the tractor through the link  31 . 
   The liquid reservoir  13  and the sump  14  are shown in  FIG. 6 . As illustrated, the liquid reservoir and vacuum chamber have a common enclosure with an internal partition dividing them. The sump  14  has a inlet  57  for connection by hose  28  to the vacuum shroud  27 . An outlet  58  is connected to the vacuum pump hose  66 . The liquid reservoir has a hatch  60  for inspecting and cleaning the reservoir with approximately 600-1500 gallons of liquid. An outlet  61  is connected to a low pressure pump by a low pressure suction hose  62 . The low pressure 12 volt pump is used to pump water out of the reservoir  13  back to the water blasting pump  67  about 40 Psi and 20 g.p.m. 
   A recycling valve  63  is mounted in a connector pipe  68  having one end opening into the reservoir  13  and the other end opening into the sump  14 . The connector is located near the top of the sump and reservoir to allow for some settling of debris in the sump. The valve  63  opens or closes the connection. 
   In  FIG. 7 , the sump  14  is shown with the rear door  65  open for unloading the porous enclosure  64 . The door has a seal (not shown) to maintain the negative pressure therein during operation. The porous enclosure may be a wire screen or mesh box sized to fit within the sump  14 . An additional filter bag  68  having between 5-200 micron porosity may be inserted into the enclosure. The dimensions of the enclosure  64  are somewhat less than the interior of the sump which provides a marginal area  80  between the enclosure and the interior walls and floor of the sump which provides an exit path for filtered water through valve  70 . The inlet  57  empties into the enclosure  64  thereby preventing coatings from being entrained in the vacuum system. One side of the enclosure is hinged and latched to permit entry into the enclosure or removal of the filtered bags. By opening the sump door and raising the dump bed of the truck, the waste material can be easily and quickly removed without prolonged interruption of the operations. The filtered bag is the disposal container, and is dumped with the material. A permanent filter material can also be utilized which requires cleaning after each use but does not waste a filter bag each time it is dumped. 
   In operation, the process for using the disclosed equipment in a mobile operation for stripe removal: 
   1. Connection valve remains closed. Water side is used only as a fresh water supply and is not placed under vacuum at any time. 
   2. Filter material position in the vacuum tank at a distance off the walls and floor of the tank. A filter tank “bag” may also be hung by hooks from the ceiling to produce even cleaner waste water. 
   3. The vacuum tank is placed under vacuum by starting the diesel powered vacuum pump which is connected by an air outlet hose to the vacuum tank. 
   4. As strip material is removed creating a slurry of water and debris, the mixture is drawn through the inlet hose into the vacuum tank being trapped in the filter. 
   5. When the vacuum tank reaches its full capacity, a shutoff ball is forced upwards towards the air outlet hose and makes contact with a ball seal causing loss of tank vacuum. 
   6. The drain valve is then opened on the vacuum tank, and into the open cavity between the walls and floor allowing an exit from the drain. 
   7. The shutoff valve is closed allowing for a capacity equal to the capacity previously occupied by dirty water, only the debris slurry remains inside the tank. 
   8. Steps 1-7 are repeated until the strip is removed. 
   9. Upon opening of a door to the vacuum container, allows for a removal of all debris captured in the filter. 
   The instant invention may also be used in a non-mobile setting in continuous operation as follows. 
   1. The connection valve remains open except when it is necessary to dump the water side. Water side is used as an overflow vacuum tank and is under vacuum much of the time. 
   2. Filter material positioned in the vacuum tank at a distance off the walls and floor of the tank. A filter “bag” may also be hung by hooks from the ceiling to produce even cleaner waste water. 
   3. Vacuum tank is placed under vacuum by starting the diesel powered vacuum pump which is connected by the air outlet hose to the vacuum tank. Water side is under vacuum as well by way of connection valve. 
   4. As strip material is removed creating a slurry of water and debris, the mixture is drawn through the inlet hose into the vacuum tank being trapped in the filter. 
   5. As the debris and water level rise to the level of the connection valve, the water will begin flowing through the connection valve into the water side. The water in the water side tank will be filtered water as the water has had to first flow through the filter material to reach the connection valve. 
   6. When the waste water has reached the level of the connection valve it will be visible to the operator through a strategically positioned sight glass. At that point, without shutting down the vacuum or the operation, the operator closes the connection valve which releases the water side tank from vacuum. 
   7. Next, the operator must open the drain valve on the water side to release the waste water being held there. 
   8. After the water tank has drained completely, the water side drain valve must be closed. 
   9. The connection valve is reopened allowing wastewater to flow freely into the water side box. 
   10. Repeating of steps 1-9 while never shutting down or affecting the blasting operation whatsoever. This may be continued until the vacuum tank is full of debris. 
   11. It is now necessary to shut off the vacuum power unit and open the drain valve on the vacuum tank. This allows the water to drain through the filter material, into the open cavity between the walls and floor, and exit the drain. This allows the debris to dewater. 
   12. Opening of the vacuum door allows for a release of all material to repeat the process. 
   A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiment but only by the scope of the appended claims.