Method and device for supplying cleaning fluid

Abstract

An apparatus can include a side wall, wherein the side wall defines an inner portion and an outer portion, wherein the side wall comprises a top end and a bottom end; a base attached to the bottom end; and an aperture within the side wall, wherein the aperture extends from the outer portion to the inner portion, wherein the aperture is configured to permit a fluid flow from the outer portion to the inner portion.

Description

[0001] Method and Device for Supplying Cleaning Fluid Background

[0002] Disclosed is a method and device for cleaning a paint supply passage.

[0003] In a painting process where the body of an automobile is painted, a cleaning process is carried out when, for example, a "color change" is made to change to a different color of paint. In the cleaning process, a cleaning liquid is used to clean the paint supply path.

[0004] JP 2008-307480A discloses a detailed explanation of a cleaning process for a paint supply path including a sprayer. JP 2008-307480A discloses a method for cleaning a paint supply path including a sprayer by supplying a cleaning liquid to the paint supply path under pressure. To summarize the description of JP 2008-307480A, in the past, the paint supply path was cleaned by supplying a cleaning liquid to the paint supply path under pressure from the beginning to the end of the cleaning process, but this had the problem of requiring a large amount of cleaning liquid. To address this problem, a method was adopted for cleaning the paint supply path using a cleaning liquid containing air bubbles, which is a cleaning liquid that has air mixed in it.

[0005] JP 2008-307480A verified the correlation between the supply of cleaning liquid and the cleaning effect in the cleaning process and discovered that in the early stages of cleaning with the cleaning liquid, the cleaning efficiency increases dramatically over time, but thereafter the increase in cleaning efficiency becomes slower. Based on this fact, JP 2008-307480A proposes the following cleaning method and cleaning device.

[0006] Specifically, in JP 2008-307480 A, based on a predetermined time chart, first, cleaning liquid is supplied under pressure to a paint supply path for a predetermined time, then the cleaning liquid is switched to air and the air is supplied to the paint supply path for a predetermined time, then the air is switched back to cleaning liquid and the cleaning liquid is supplied to the paint supply path for a predetermined time. The cleaning device disclosed in JP 2008-307480A has a cleaning liquid on-off valve and an air on-off valve at the upstream end of the paint supply path, and the cleaning liquid on-off valve and the air on-off valve are alternately switched between open and closed based on a predetermined time chart. By using this cleaning device, the paint supply path can be cleaned by sequentially switching between the supply of cleaning liquid and the supply of air. Thereby, cleaning liquid and and air, but not a mixture thereof, alternately clean the paint supply path by operating on a preset schedule.

[0007] Summary An object of the present embodiments can be to provide a method and device for cleaning a paint supply passage that is simple in configuration and that can reduce the amount of cleaning liquid used.

[0008] The cleaning method and cleaning device of the present embodiments can be characterized in that, rather than cleaning the paint supply path using a conventional method of supplying cleaning liquid under pressure, the device sucks in cleaning liquid itself and uses the sucked in cleaning liquid to clean the paint supply path.

[0009] In order to achieve the above objective, the present embodiments can include cleaning a paint supply passage for supplying paint from a paint source to a paint sprayer, which can include a paint supply path that can have a pump and a suction pipe communicating with the pump, a suction pipe installation step of inserting an upstream end of the suction pipe into a cleaning liquid tank that contains a cleaning liquid and is open to the atmosphere, a pump starting step of starting the pump, wherein the force of the pump sucks air into the suction pipe together with the cleaning liquid through the suction port of the suction pipe, and the cleaning liquid mixed with air bubbles is discharged at the upstream end of the suction pipe. This can also include a cleaning liquid generating step of generating a cleaning liquid containing air bubbles, forming a mixture. The paint supply path can be cleaned with the cleaning liquid containing air bubbles, thereby providing a method for cleaning the paint supply path.

[0010] Brief Description of the Figures

[0011] FIG. l is a diagram for explaining an overview of a prior art paint supply system for supplying paint to a sprayer.

[0012] FIG. 2 is a reference diagram for explaining a prior art cleaning method for a paint supply path.

[0013] FIG. 3 is an example, non-limiting view of a cleaning device used in the cleaning method of the present embodiments.

[0014] FIG. 4 is an example, non-limiting diagram for explaining a state after a preparation process prior to carrying out the cleaning method of the embodiments being performed.

[0015] FIG. 5 is an example, non-limiting diagram for explaining a first stage of the cleaning method of the embodiments.

[0016] FIG. 6 is an example, non-limiting diagram for explaining a second stage of the cleaning method of the embodiments. FIG. 7 is an example, non-limiting diagram for explaining a modification of the cleaning device shown in FIG. 3.

[0017] DETAILED DESCRIPTION

[0018] The following description of certain examples of the embodiments should not be used to limit its scope. Other examples, features, aspects, and advantages of the technology will become apparent to those skilled in the art from the following description, which is by way of illustration, one of the best triodes contemplated for carrying out the embodiments. As will be realized, the embodiments described herein can be capable of other different and obvious aspects, all without departing from the embodiments. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.

[0019] In the description, figures, and tables which follow, a number of terms are used. In order to provide the specifications and claims, including the scope to be given such terms, the following definitions are provided: As used herein, “a” can mean one or more, depending on the context in which it is used.

[0020] FIG. 1 shows an overview of a prior art paint supply system for supplying paint to a sprayer. In the figure, reference numeral 2 indicates an applicator, which can be a sprayer, and reference numeral 4 indicates a coating tank that is a coating source. The coating tank is configured as a tank open to the atmosphere. A pump 6 and a branch valve 8 are interposed between the coating tank 4 and the applicator 2, and a paint in the coating tank 4 is sucked in by the pump 6 through a coating delivery line 10. FIG. 1 illustrates an example in which a diaphragm pump is adopted as the pump 6. Paint discharged from the pump 6 is supplied to the branch valve 8 through a discharge pipe 12, and the paint is then supplied from the branch valve 8 to the applicator 2 and sprayed. Meanwhile, unused paint is returned to the coating tank 4 through a waste liquid delivery line 14. That is, the branch valve 8 is configured as a three-way valve, and the paint is circulated in a state of passing through the three-way valve and returning to the coating tank 4.

[0021] The paint supplied from the coating deliver line 10 to the three-way valve is supplied to the applicator 2 by the operation of the three-way valve in response to an external signal, and is then sprayed from the applicator 2.

[0022] The cleaning method according to the present embodiments can be suitably applied to cleaning a paint supply path 20 which can include a coating delivery line 10, a pump 6, a discharge pipe 12, a branch valve 8, and a waste liquid delivery line 14. Note that the area from the branch valve 8 to the applicator 2 is cleaned by a separate system.

[0023] For reference, a prior art cleaning method for the paint supply passage 20 will be described with reference to FIG. 2. In a preparation step prior to the cleaning step, first, the suction port 10a of the coating delivery line 10 is cleaned. The upstream end of the coating delivery line 10, including the suction port 10a, is removed from the coating tank 4, and the upstream end of the coating delivery line 10 is inserted into the cleaning liquid tank 22. The cleaning liquid tank 22 is a tank that is open to the atmosphere. The cleaning liquid tank 22 contains cleaning liquid CL. Secondly, in the preparation process, the downstream end of the waste liquid delivery line 14 is removed from the coating tank 4 and inserted into the waste liquid tank 24. The waste liquid tank 24 is a tank that is open to the atmosphere. The preparation process is completed by carrying out the above first and second operations.

[0024] After the preparation process is completed, the pump 6 can be actuated to start cleaning the paint supply path 20. The contaminated cleaning liquid generated in the cleaning process is collected in the waste liquid tank 24 via the waste liquid delivery line 14.

[0025] As shown in FIGS. 3-7, the cleaning method of the present embodiments, an apparatus 30 of the embodiments shown in Fig. 3 can be used. The apparatus 30 can include a base plate 32 and an additional container 34, wherein the container has at least one side wall 35. The side wall 35 defines an inner portion 33 and outer portion 31. The container 34 can have a configuration in which one end (the lower end in Fig. 3 ) of a cylindrical member can be closed by the base plate 32. In other words, the additional container 34 can have a configuration in which the upper end can be open to the atmosphere and the bottom surface can be formed by the base plate 32 and can be sealed by the base plate 32. The apparatus 30 can be used in a state in which the additional container 34, which can be open to the atmosphere, stands upright facing upward from the base plate 32 in the cleaning liquid tank 22 containing the cleaning liquid CL.

[0026] The apparatus 30 can be a relatively heavy object made of, for example, stainless steel, and the base plate 32 has a size that prevents the apparatus 30 from tipping over in the cleaning liquid tank 22. In the cleaning liquid tank 22 containing the cleaning liquid CL, the base plate 32 of the apparatus 30 touches the bottom surface of the cleaning liquid tank 22, and the additional container 34 standing upright from the base plate 32 maintains its upright position. The container 34 can have a bottom end 37 attached to the base plate 32 and a top end 39 that can extend beyond the top level of cleaning liquid CL in the cleaning liquid tank 22. The side wall 35 can define an inner portion 33 and outer portion 31 of the container 34.

[0027] When the apparatus 30 can be installed in the cleaning liquid tank 22, the additional container 34 has a length dimension such that its open upper end can be positioned above the liquid level of the cleaning liquid CL in the cleaning liquid tank 22.

[0028] The additional container 34 can have anl aperture 36 at its bottom end, which can be small and circular. The aperture 36 has the function of restricting the amount of cleaning liquid CL in the cleaning liquid tank 22 flowing into the additional container 34 while allowing the cleaning liquid CL to flow into the container 34. The amount of cleaning liquid CL flowing into the additional container 34 through the aperture 36 can be smaller than the amount sucked in by the pump 6. The additional container 34 may have one aperture 36, but can have multiple apertures 36.

[0029] The aperture 36 can be an example of a flow rate regulating opening that restricts the amount of cleaning liquid flowing from the cleaning liquid tank 22 to the additional container 34. The shape of the flow rate regulating opening can be arbitrary. Instead of the single or multiple circular apertures 36, the flow rate regulating opening may be a single or multiple non - circular holes or a single or multiple slits.

[0030] As described above, the flow rate regulating opening, of which the aperture 36 can be a typical example, has the function of restricting the amount of inflow while allowing the cleaning liquid CL in the cleaning liquid tank 22 to flow into the additional container 34. A preferred example of the function of restricting the amount of inflow will be described below.

[0031] A flow rate at which the pump 6 sucks in the cleaning liquid can be Qp and the inflow rate of the cleaning liquid flowing into the container 34 through the aperture 36 can be Qh, then the absolute condition can be Qp>Qh. A relationship between Qp and Qh can be 0.3 x Qp < Qh < 0.7 x Qp. If the size of the flow rate regulating opening can be designed so that this condition can be satisfied, the amount of cleaning liquid used can be reduced by 30 % to 70 % compared to the prior art cleaning method in which cleaning can be performed using only cleaning liquid. In other embodiments, 0.4 x Qp < Qh < 0.6 x Qp. If the size of the flow rate regulating opening can be designed so that this condition can be satisfied, the amount of cleaning liquid used can be reduced by half compared to prior art cleaning methods that use only cleaning liquid. The apparatus 30 of the embodiment can include a plurality of flow restriction attachments 38 having different passage cross - sectional areas. On the other hand, the circular aperture 36 can be configured as a screw hole. If necessary, a flow restriction attachment 38 having a preferred passage cross-sectional area can be detachably screwed into the aperture 36. This makes it possible to adjust the substantial effective opening area of the aperture 36 by the flow restriction attachment 38. By selecting the flow restriction attachment 38 having an appropriate passage cross-sectional area, the amount of the cleaning liquid CL flowing into the additional container 34 can be adjusted.

[0032] The flow restriction attachment 38 can be attached to and detached from the aperture 36 by screwing it in, but as a modified example, a configuration in which the flow restriction attachment 38 can be detachably fitted into the aperture 36 may be used.

[0033] Inside diameter of additional container 34 open to atmosphere . D ( FIG. 3 ) can be the diameter of the container 34 and Di of the filter attachment 40 located at the upstream end of the coating delivery line 10. Specifically, it can be preferable to set the upstream end including the filter attachment 40 to a value that allows the upstream end including the filter attachment 40 to be inserted into the container 34 from the top end 39 opening of the additional container 34, and preferably to a value as small as possible.

[0034] The operation of the apparatus 30 of the embodiment can be described with reference to FIGS. 4-6. In FIGS. 4-6, the filter attachment 40 can be omitted to avoid cluttering the diagrams. Before cleaning the paint supply path 20, the following preparations are made.

[0035] In a preparation step, the apparatus 30 can be installed in the cleaning liquid tank 22 containing the cleaning liquid CL. The additional container 34, which can be a component of the apparatus 30, has its top end 39 open to the atmosphere. Therefore, when the apparatus 30 can be installed in the cleaning liquid tank 22, the cleaning liquid CL in the cleaning liquid tank 22 immediately flows into the container 34 through the aperture 36, and within a short period of time, the container 34 can be filled with cleaning liquid. The upstream end of the coating delivery line 10 can be removed from the coating tank 4, which can have any coating fluid, including paint, and inserted into the additional container 34 from the upper opening of the container 34. The coating delivery line 10 has its suction port 10a, which can be positioned near the bottom end of the additional container 34 while being separated from the bottom of the container 34. The waste liquid delivery line 14 can be removed from the coating tank 4, and the downstream portion of the waste liquid delivery line 14 can be inserted into the waste liquid tank 24 which can be open to the atmosphere. By carrying out the above operations, the paint supply path 20 can be prepared for cleaning.

[0036] After the above preparations are completed, the cleaning process can be started by actuating the pump 6. The cleaning process can be composed of a first stage and a second stage in chronological order. In the first stage, the cleaning liquid CL in the additional container 34 can be sucked in by the pump 6 through the coating delivery line 10, and the paint supply path 20 can be cleaned with the cleaning liquid (FIG. 5). The contaminated cleaning liquid used for cleaning can be stored in the waste liquid tank 24, which can be open to the atmosphere. This removes most of the paint remaining in the paint supply path 20 from the paint supply path 20.

[0037] In the first stage, the level of the cleaning liquid in the additional container 34 drops as the cleaning liquid can be sucked in by the coating delivery line 10, and the cleaning liquid CL in the cleaning liquid tank 22 open to the atmosphere flows into the container 34 through the aperture 36. The relationship between the amount of cleaning liquid flowing into the container 34 through the aperture 36 and the amount of suction by the pump 6 can be as described above. That is, the opening area of the aperture 36 can be set so that the amount of cleaning liquid flowing into the additional container 34 through the aperture 36 can be smaller than the amount of suction by the pump 6, as described above (FIG. 3).

[0038] By way of example, the aperture 36 can be circular, and the diameter of the aperture 36 can be 1 mm to 5 mm.

[0039] When the cleaning with the cleaning liquid CL in the first stage progresses, the second stage automatically starts.

[0040] The surface of the cleaning liquid in the additional container 34 can be moved to the suction port 10a of the coating delivery line 10, and cleaning can be performed with the cleaning liquid containing air bubbles. When the additional container 34 approaches the suction port 10a of the coating delivery line 10, the air above the cleaning liquid in the additional container 34 can be sucked in by the pump 6 while being mixed with the cleaning liquid (FIG. 6). Air can be sucked into the coating delivery line 10 together with the cleaning liquid through the nozzle 30, and as a result, the upstream end of the coating delivery line 10 can be a part of the apparatus 30, and cleaning liquid containing air bubbles can be generated at the upstream end of the coating delivery line 10. Thus, in the second stage, the upstream end of the coating delivery line 10 exerts the function of generating cleaning liquid containing air bubbles, and the paint supply path 20 can be cleaned with the cleaning liquid containing air bubbles.

[0041] As described above, the amount of the cleaning liquid CL flowing into the additional container 34 through the aperture 36 can be less than the amount of the cleaning liquid CL sucked in by the pump 6. For this reason, in the second stage, the liquid level of the cleaning liquid in the additional container 34 can be lower than the suction port 10a of the coating delivery line 10. When the temperature drops to the vicinity of 100° C., the cleaning liquid containing air bubbles will contain a large amount of air bubbles, but the cleaning liquid containing air bubbles will continue to clean the paint supply path 20 until the operation of the pump 6 can be stopped.

[0042] The base plate 32 and container 34 included in the above-mentioned apparatus 30 have a structure in which one additional container 34 can be arranged on the base plate 32, but as a modified example, as shown in Fig. 7, a configuration in which a plurality of (e.g., four) additional containers 34 are arranged on one base plate 32 may be provided. In the paint supply system shown in Fig. 1, when a gear pump can be used as the pump 6, it can be desirable to simultaneously clean the four paint supply paths 20 associated with each of the four sprayers 2. The modified example shown in Fig. 7 can meet this demand.

[0043] According to an embodiment, the apparatus 30 can include a side wall 35, wherein the side wall 35 can define an inner portion 33 and an outer portion 31, wherein the side wall 35 can include a top end 39 and a bottom end 37, a base 37 attached to the bottom end 37; and an aperture within the side wall 35, wherein the aperture can extend from the outer portion 31 to the inner portion 33, wherein the aperture is configured to permit a fluid flow from the outer portion 31 to the inner portion 33.

[0044] According to certain embodiments, the aperture can be a plurality of apertures, and wherein the plurality of apertures are closer to the bottom end 37 than the top end 39. In some embodiments, the apparatus 30 can provide that the plurality of apertures are configured to receive a plurality of flow restriction attachment 38s that permit, but further restrict, the fluid flow from the outer portion 31 to the inner portion 33. In some embodiments, the base 37 comprises stainless steel, and wherein the base 37 extends beyond the at least one side wall 35 to be in direct adjacent contact with the outer portion 31 and the entirety of an inner portion 33 bottom end 37. In some embodiments, the at least one side wall 35 is a cylindrical wall. In certain embodiments, a system 47 can include the apparatus 30 described herein, a pump 6; a coating delivery line 10; an applicator 2; a branch valve 8; a waste liquid delivery line 14; a waste liquid tank; and a cleaning liquid tank 22. In some embodiments, the system 47 can provide that the apparatus 30 is within the at least one cleaning liquid tank 22, the coating delivery line 10 is partially disposed within the apparatus 30 and in fluid communication with the pump 6, the pump 6 is in fluid communication with branch valve 8, the branch valve 8 is in fluid communication with the applicator 2 and the waste liquid tank, wherein the branch valve 8 is in fluid communication with the waste liquid tank by the waste liquid delivery line 14. According to certain embodiments, the system 47 can further include further comprising a filter 40 attachment, wherein the filter 40 is disposed on the coating delivery line 10 and at least partially disposed within the apparatus 30. According to some embodiments, the system 47 can provide that the pump 6 is is fluid communication with the branch valve 8 via a discharge pipe, wherein the pump 6 is configured to have a pump 6 flow rate Qp, the aperture is configured to have a aperture flow rate Qh, and wherein 0.3 * Qp < Qh < 0.7 * Qp. In some embodiments, the system 47 a plurality of apparatus 30es.

[0045] According to some embodiments, a method can include providing the apparatus 30 or system 47 described herein, removing the coating delivery line 10 from a fluid supply tank; and placing the coating delivery line 10 into the inner portion 33 of the apparatus 30. In some embodiments, the method can further include placing the apparatus 30 into the cleaning liquid tank 22; and at least partially filling the apparatus 30 with cleaning liquid via a flow of cleaning liquid from the outer portion 31 into the inner portion 33 via the aperture. In some embodiments, the method of can include actuating the pump 6. According to certain embodiments, the method can include setting the branch valve 8 to restrict flow to the applicator 2 and permit flow to the waste liquid tank. In certain embodiments, the method can include pump 6ing a mixture of cleaning liquid and air bubbles through the coating delivery line 10, the pump 6, and the branch valve 8.

Claims

ClaimsWe claim:

1. An apparatus, comprising: a side wall, wherein the side wall defines an inner portion and an outer portion, wherein the side wall comprises a top end and a bottom end; a base attached to the bottom end; and an aperture within the side wall, wherein the aperture extends from the outer portion to the inner portion, wherein the aperture is configured to permit a fluid flow from the outer portion to the inner portion.

2. The apparatus of claim 1, wherein the at least one aperture is a plurality of apertures, and wherein the plurality of apertures are closer to the bottom end than the top end.

3. The apparatus of claim 2, wherein the plurality of apertures are configured to receive a plurality of flow restriction attachments that permit, but further restrict, the fluid flow from the outer portion to the inner portion.

4. The apparatus of claim 1, wherein the base comprises stainless steel, and wherein the base extends beyond the at least one side wall to be in direct adjacent contact with the outer portion and the entirety of an inner portion bottom end.

5. The apparatus of claim 1, wherein the at least one side wall is a cylindrical wall.

6. A system comprising: the apparatus of claim 1; a pump; a coating delivery line; an applicator; a branch valve; a waste liquid delivery line; a waste liquid tank; and a cleaning liquid tank.

7. The system of claim 6, wherein the apparatus is within the at least one cleaning liquid tank, the coating delivery line is partially disposed within the apparatus and in fluid communication with the pump, the pump is in fluid communication with branch valve, the branch valve is in fluid communication with the applicator and the waste liquid tank, wherein the branch valve is in fluid communication with the waste liquid tank by the waste liquid delivery line.

8. The system of claim 7, further comprising a filter, wherein the filter is disposed on the coating delivery line and at least partially disposed within the apparatus.

9. The system of claim 8, wherein the pump is is fluid communication with the branch valve via a discharge pipe, wherein the pump is configured to have a pump flow rate Qp, the aperture is configured to have a aperture flow rate Qh, and wherein 0.3 * Qp < Qh < 0.7 * QP10. The system of claim 6, comprising a plurality of apparatuses.

11. A method comprising: providing the system of claim 6; removing the coating delivery line from a fluid supply tank; and placing the coating delivery line into the inner portion of the apparatus.

12. The method of claim 11, further comprising: placing the apparatus into the cleaning liquid tank; and at least partially filling the apparatus with cleaning liquid via a flow of cleaning liquid from the outer portion into the inner portion via the aperture.

13. The method of claim 11, futher comprising: actuating the pump.

14. The method of claim 11, further comprising: setting the branch valve to restrict flow to the applicator and permit flow to the waste liquid tank.

15. The method of claim 11, further comprising:5 pumping a mixture of cleaning liquid and air bubbles through the coating delivery line, the pump, and the branch valve.

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