PALLET COATING WASTE RECOVERY SYSTEM

Abstract

The present invention relates to a self-contained unit having a system for recovering polymer overspray from a pallet coating process. The self-contained unit includes a common enclosure having at least four walls, a ceiling and a floor. There is a collection tank located below the floor of the common enclosure and a roof platform is located above the ceiling of the common enclosure. Within the common enclosure is at least one spray booth having a waterfall wall with liquid flowing down a face of the waterfall wall to the collection tank. Mounted on the roof platform is a consolidation tank, hydrocyclone and pressure filter that are all part of the system for removing the polymer from the overspray mixture collected at the collection tank.

Claims

1. A consolidation tank for recovering waste material, comprising: a container; a horn configured to turbulently introduce a waste mixture into the container; and an air disk configured to generate microbubbles in the container, wherein the microbubbles facilitate separation of solid particles from the waste mixture for removal from the container.

2. The consolidation tank of claim 1 further comprising a scraper configured to remove solid particles.

3. The consolidation tank of claim 1, wherein the container is configured to interface with a chute to enable removal of solid particles from the container.

4. The consolidation tank of claim 1 further comprising a first outlet coupled to the container, wherein solid particles from the waste mixture that sink to a bottom of the container are configured to be removed from the container through the first outlet.

5. The consolidation tank of claim 1 further comprising a second outlet coupled to the container, wherein liquid from the waste mixture is configured to be removed from the container through the second outlet.

6. The consolidation tank of claim 1, wherein the horn includes at least one outlet configured to turbulently introduce the waste mixture into the container.

7. The consolidation tank of claim 1 further comprising a wand positioned at least partially within the container, wherein the wand includes a base that rests on a portion of the horn, and wherein the base defines a surface for receiving the air disk.

8. The consolidation tank of claim 1, wherein the air disk is configured to receive air from an air source through an air line.

9. The consolidation tank of claim 1, wherein the air disk is configured to generate microbubbles having an average diameter in the range of about 50 to 200 micrometers at a pressure in the range of about 1 to 2 bar.

10. A consolidation tank for recovering waste material, comprising: a container having an inlet; a horn coupled to the inlet, wherein the horn includes a first outlet configured to turbulently introduce a waste mixture into the container; and an air disk configured to generate microbubbles in the container to enable solid particles from the waste mixture to float to a top of the container, wherein the solid particles are removable from the top of the container.

11. The consolidation tank of claim 10 further comprising a scraper configured to collect solid particles and push the solid particles to a chute for removal.

12. The consolidation tank of claim 10 further comprising: a seat formed on the horn proximate the first outlet; and a base positioned against the seat, the base defining a surface for receiving the air disk.

13. The consolidation tank of claim 10, wherein the horn includes a second outlet configured to operate with the first outlet to turbulently introduce a waste mixture into the container.

14. The consolidation tank of claim 10 further comprising a third outlet coupled to the container, wherein solid particles from the waste mixture that sink to a bottom of the container are configured to be removed from the container through the third outlet.

15. The consolidation tank of claim 10 further comprising a fourth outlet coupled to the container, wherein liquid from the waste mixture is configured to be removed from the container through the fourth outlet.

16. The consolidation tank of claim 10, wherein the air disk is configured to receive compressed air from an air source through an air line.

17. The consolidation tank of claim 10, wherein the air disk is configured to generate microbubbles having an average diameter in the range of about 50 to 200 micrometers.

18. The consolidation tank of claim 10, wherein the air disk is configured to generate microbubbles having an average diameter of about 120 micrometers.

19. The consolidation tank of claim 10, wherein the air disk is configured to generate microbubbles at a pressure in the range of about 1 to 2 bar.

20. A consolidation tank for recovering waste material, comprising: a container having an inlet; a horn coupled to the inlet, wherein the horn includes a first outlet and a second outlet configured to turbulently introduce a waste mixture into the container; a seat formed on the horn between the first outlet and the second outlet; a wand having an air disk coupled to a base, wherein the base is coupled to the seat, and wherein the air disk is configured to generate microbubbles in the container to facilitate separation of solid particles from the waste mixture; a third outlet coupled to a bottom of the container, wherein solid particles from the waste mixture that sink to a bottom of the container are configured to be removed from the container through the third outlet; and a fourth outlet coupled to a side of the container, wherein liquid from the waste mixture is configured to be removed from the container through the fourth outlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0010] FIG. 1 is a liquid flow diagram of a system for recovering polymer overspray from a collection tank.

[0011] FIG. 2 is a front side perspective view of a self-contained unit for recovering waste from a pallet coating process.

[0012] FIG. 3 is a phantom perspective view of portions of the self-contained unit for recovering waste from a pallet coating process.

[0013] FIG. 4 is a rear side perspective view of a self-contained unit for recovering waste from a pallet coating process.

[0014] FIG. 5 is a top side perspective view of a collection tank with side walls removed.

[0015] FIG. 6 is a first end elevational view of the collection tank.

[0016] FIG. 7 is a second end elevational view of the collection tank.

[0017] FIG. 8 is a right side elevational view of the collection tank.

[0018] FIG. 9 is a side cross sectional schematic view of a consolidation tank.

[0019] FIG. 10 is a side elevational view of a cone bottom tank.

[0020] FIG. 11 is a top plan view of the cone bottom tank.

[0021] FIG. 12 is a top perspective view of a pressure filter.

[0022] FIG. 13 is a right side elevational view of the pressure filter.

[0023] FIG. 14 is a sectional side perspective view of the consolidation tank.

[0024] FIG. 15 is a side perspective view of a wand for creating microbubbles in the consolidation tank.

[0025] FIG. 16 is a side elevational view of the hydrocyclone.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0027] Referring now to all the figures, a system 10 which includes a self-contained unit 11 for recovering waste from a pallet coating process where polyurea or polyurethane is sprayed on to a pallet in a wet spray booth. The system 10 provides for recovering polymer overspray from a collection tank 16. The polymer overspray includes what is generally referred to as polymer, however, in some embodiments the polymer is polyurea or polyurethane. However, it is within the scope of this invention for the polymer to be any type of polymer and can include other materials such as adhesive, paint, wax and organic compounds including oil. The self-contained unit 11 that contains all of the components of the system 10 on a single structure, which separates the pallet coating process from the surrounding environment. The self-contained unit 11 provides a common enclosure 13 for conducting a pallet coating process. The common enclosure 13 has four walls 108a, 108b, 108c, 108d a ceiling 110 and a floor 112 that separate the interior environment of the self-contained unit 11 from the surrounding environment. Above the ceiling 110 of the common enclosure 13 is a roof platform 114 used to mount various components for removing polymer, as described below. Below the floor 112 is a collection tank 16, that is also used to collect polymer overspray. The interior of the common enclosure 13 creates an application area where polymer coating material is applied to the pallets, while the polymer removal or recovery occurs outside of the common enclosure 13, but still on the self-contained unit 11 as described herein.

[0028] Within the interior of the self-contained unit 11 pallets are coated with polymer and waste material, in the form of polymer overspray, which is a mixture of liquid and solid or semi-solid polymer that is over-sprayed past the pallet, is separated and collected directly from different components of the self-contained unit 11. The surrounding environment can be a warehouse, outdoor lot or any desired location. The system 10 is modular and can be disassembled and reassembled at a different location. The system 10 includes spray booths 12a, 12b that are in the common enclosure 13, which has a floor drain edge 118a, 118b to a common collection tank 16 located below the floor 112 of the common enclosure 13 of the self-contained unit 11. In the present embodiment of the invention there are two spray booths, however, it is within the scope of this invention for there to be a greater or lesser number of spray booths depending on the size of the common housing unit 13 and a particular application.

[0029] Each of the spray booths 12a, 12b has a waterfall wall 14a, 14b with liquid flowing down a face of the waterfall wall 14a, 14b to the floor drain edge 118a, 118b of the collection tank 16. The type of liquid is typically water; however, it is within the scope of the invention for the liquid to be made of an organic solvent or aqueous solution.

[0030] Within the spray booth 12a, 12b is a workpiece holder 18a, 18b for holding a workpiece 20a, 20b, wherein the waterfall wall 14 is positioned on a first side of the workpiece holder 18a, 18b. The work piece holder 18a, 18b can be a turn table that is able to rotate the work piece 20a, 20b three-hundred-sixty degrees. In the present embodiment of the invention the work piece 20a, 20b is a pallet made of wood or polymer material that is coated with a polymer material. The polymer material can be virtually any type of material capable of being sprayed and includes but is not limited to polyurea or polyurethane. It is within the scope of this invention for the work piece 20a, 20b to be some other article that would benefit from spray polymer coating.

[0031] Each spray booth 12a, 12b further includes a spray applicator 24a, 24b for spraying a polymer onto the respective workpiece 20a, 20b positioned on the workpiece holder 18a, 18b. The spray applicator 24a, 24b in a preferred embodiment is a robotic arm with a nozzle, however, it is within the scope of the invention for the spray applicator 24a, 24b to be a manually operated spray gun that is held and manually operated by a person. An overspray 26a, 26b of polymer from the spray applicator 24a, 24b that travels past the workpiece 20a, 20b contacts the liquid of the waterfall wall 14a, 14b, wherein the overspray of polymer and the liquid form an overspray mixture 27 drains past the respective floor drain edge 118a, 118b and is collected in the collection tank 16.

[0032] Referring also to FIGS. 5-8 the details of the collection tank 16 are shown. As shown best in the schematic in FIG. 1, the collection tank 16 receives liquid from three sources, which from the overspray mixture 27. The overspray mixture in the collection tank 16 includes liquid from the waterfall wall 14a, 14b, liquid from a pressure filter 70 and liquid from a consolidation tank 48, all of which are described in greater detail below. The hydrocyclone 34, the consolidation tank 48 and the pressure filter 70 are all located on the roof platform 114. This separates the polymer reclamation process from the pallet coating process, which occurs within the common enclosure 13.

[0033] The collection tank 16 has a first outlet 28 and a second outlet 30. The first outlet 28 is connected to an autoweir 29 that has a hinged door positioned at the surface of the overspray mixture in the collection tank 16. The hinged door has a float that causes the hinged door to move vertically and track with the surface level of the overspray mixture 27 to remove concentrated polymer solids suspended in a mixture with the liquid. While the autoweir 29 shown is vertically stationary or manually adjusted vertically, it is within the scope of the invention for a floating weir to be used. An example of a floating weir is described in U.S. Pat. No. 10,525,380 B2 entitled FLOATING CHOPPER SLUDGE WEIR issued to Applicant Air and Liquid Systems, Inc. of Rochester Hills, MI; the entire contents of the application are hereby expressly incorporated by reference. The floating polymer material which is concentrated and mixed with liquid is collected by the autoweir 29 and the first outlet 28.

[0034] Referring to FIGS. 1 and 16 a hydrocyclone pump 32 (shown in FIG. 1) is connected to the second outlet 30 of the collection tank 16 and pumps polymer material and liquid from the bottom of the collection tank 16 to an inlet 35 the hydrocyclone 34. The hydrocyclone pump 32 pressurizes the floating polymer and liquid collected from the bottom of the collection tank 16, which then enters the hydrocyclone 34. In the hydrocyclone 34 a vortex of liquid and polymer is formed, which mechanically separates the polymer particles so the polymer particles (with minor amounts of liquid) exit one side of the hydrocyclone and the liquid exits a second side as described below. The hydrocyclone 34 separates the liquid received from the collection tank 16 into a first solid rich mixture 38 which contains mostly solid polymer and a return liquid 39, which is the same liquid that flows across the waterfall walls 14a, 14b. The first solid rich mixture 38 is removed from a first outlet 40 of the hydrocyclone 34 and the return liquid 39 is removed from the second outlet 42. The volume of return liquid 39 from the hydrocyclone 34 can be large and as a result a portion that is sent back to inlets 44a, 44b of the waterfall wall 16a, 16b and another portion is sent back to the collection tank 16 through the port 104. Referring to FIGS. 1 and 9, the system 10 further includes a consolidation tank pump 46 connected to the first outlet 28 of the collection tank 16. The first outlet 28 is connected to the autoweir 29 and receives overspray mixture which has concentrated polymer material in liquid from the surface of the overspray mixture in the collection tank. The overspray mixture from the first outlet 28 is removed by the consolidation tank pump 46 and inputted at an inlet 50 of the consolidation tank 48. Within the consolidation tank 48 micro-bubbles are introduced into the overspray mixture in the consolidation tank 48, which causes some of the polymer float, while some polymer will sink. The consolidation tank 48 includes a surface scraper 52 for collecting floating polymer and creating a second solid rich mixture 53 proximate to the surface of the consolidation tank 48. The surface scraper 52 pushes the second solid rich mixture 53 into a chute 54. The consolidation tank 48 is located on the roof platform 114 so that gravity removes the second solid rich mixture 53 through the chute 54. The polymer that settles to a bottom surface 56 of the consolidation tank 48, forms a third solid rich mixture 58 that is removed using an outlet 60. A return liquid 49 from the consolidation tank 48 leaves through an outlet 51 and is sent back to the collection tank 16 through the port 106.

[0035] The system 10 further includes a cone bottom tank 62, the details of which are shown in FIGS. 10 and 11, for receiving the first solid rich mixture 38, the second solid rich mixture 53 and the third solid rich mixture 58 which are combined to form a cone tank mixture 61 that contains the polymer and the liquid, where the polymer is in greater concentration than the liquid. The cone bottom tank 62 is located below the roof platform 114, where the first solid rich mixture 38, the second solid rich mixture 53 and the third solid rich mixture 58 are produced. The cone bottom tank 62 has a conical surface 64 leading to an outlet 66. The cone bottom tank 62 also optionally includes a mixer or agitator 63 that mixes the cone tank mixture 61 to prevent the polymer from becoming too solid which can cause a blockage in the outlet 66.

[0036] The outlet 66 of the cone bottom tank 62 connects to a pump 68 that pumps the cone tank mixture 61 to the pressure filter 70. Referring also to FIGS. 12 and 13, the pressure filter 70 has an inlet 72 for receiving the cone tank mixture and introducing it to a drying chamber 74 for holding and drying the cone tank mixture. The drying chamber 74 has a screen in combination with a roll of media for capturing polymer from the cone tank mixture as pressurized air from an air inlet 75 is forced through the cone tank mixture to separate the cone tank mixture into a dried polymer solid and return liquid 81. The roll of media in the drying chamber has sections of varying porosity that can be used to capture different sized polymer particles. The liquid is transferred through a liquid outlet 77 of the pressure filter 70 is returned to the collection tank 16 through port 102. The dried polymer in the pressure filter 70 is formed into a dried polymer cake of polymer particles that are removed through a chute 76 and collected in a hopper 78 shown in FIGS. 1 and 4.

[0037] Referring also to FIGS. 9, 14 and 15, another aspect of the invention is now described involving the formation of the micro-bubbles 47 within the consolidation tank 48. The consolidation tank 48 further includes a horn 82 and a removable wand 80 that is placed within the consolidation tank 48. The horn 82 is a shaped tube that connects to the inlet 50. The horn 82 has two outlets 84, 86 that introduce the overspray mixture into the consolidation tank 48, in a turbulent manner to create a current vortex 49 within the consolidation tank 48. The horn 82 also has a seat 88 located between the two outlets 84, 86. The wand 80 has a base 90 that contacts and rests on the seat 88. An air disk 92 is connected to the base 90 and is connected to a compressed air line 94 to received compressed air. When compressed air from the compressed air line 94 is introduced to the air disk 92, air moves through micro-holes in the air disk 92 and create microbubbles in the consolidation tank 48. The microbubbles have an average diameter of 120 micrometers at 1 to 2 bar. The average microbubble diameter is in a range between 50 micrometers to 200 micrometers at 1 to 2 bar. The microbubbles contact the solids in the overspray mixture that is in the consolidation tank 48, which assists in causing the solids to float to the surface. While the consolidation tank 48 is described as being part of the system 10 for removing polymer particles from an overspray mixture for a pallet coating process, it is within the scope of the present embodiment of the invention for the consolidation tank 48 to be used in other systems. It is therefore within the scope of the invention for the consolidation tank 48 to be used in any system where it is desirable to remove solids from a waste mixture and not be limited to being used with a pallet coating process.

[0038] Referring now to all the figures, during operation of the system 10 a pallet is inserted through a window 15a, 15b of the self-contained unit 11. Each window 15a, 15b is near a respective one of the workpiece holders 18a, 18b where the pallet is placed. Once in place the window 15a, 15b is closed and the pallet is sprayed by the respective spray applicator 24a 24b to apply a coat of polymer material to one side. Then the pallet is flipped and the other side of the pallet is sprayed by the respective spray applicator 24a, 24b. Once the pallet has been fully sprayed the pallet is transferred out of the self-contained unit 11. Additionally, the system 10 can include an inspection device that is either located within the spray booth or connected the robotic arm that is part of the spray applicator 24a, 24b. The inspection device can be a camera or some other type of sensor. If the inspection device determines that the pallet has not been properly sprayed action can be taken such as moving the pallet to a rejected pallet area or respraying the pallet. The present embodiment of the invention employs two spray booths and two transfer robotic arms so that if one spray booth has to be shut down the other one can continue working. It is within the scope of the invention for additional spray booths and robotic arms to be used.

[0039] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.