Positive displacement reciprocating pump unit, and outside air intake device

Abstract

To improve cleaning efficiency, reduce the amount of cleaning liquid used at the time of cleaning work, and reduce the time required for cleaning.SOLUTION: A positive displacement reciprocating pump unit comprises: a positive displacement reciprocating pump comprising an inlet and an outlet for liquid serving as a transfer object, and a transfer path connecting the inlet and the outlet, and through which the transfer object flows; and an outside air intake device provided on the side of the inlet, and taking outside air into the transfer path by using a negative pressure generated in the transfer path at the time of transfer of the transfer object.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a positive displacement reciprocating pump unit and an outside air intake device. [Background technology]

[0002] It is well known that positive displacement reciprocating pump devices, such as diaphragm pumps, are used to supply paint in painting systems. In this case, after a painting job is completed, the pump must be thoroughly cleaned to prevent the paint from drying out and solidifying. Furthermore, when changing paint colors, the pump must be thoroughly cleaned to prevent the new paint colors from mixing.

[0003] Conventionally, workers have cleaned the inside of such pumps by following the steps (1) to (5) below. (1) First, the worker pulls the suction hose out of the paint tank and drains the paint accumulated inside the pump. (2) Next, the worker moves the suction hose to the cleaning liquid tank and the return hose to the waste liquid tank. This causes the cleaning liquid, such as thinner, stored in the cleaning liquid tank to be sucked into the pump through the suction hose, and the sucked cleaning liquid is then discharged from the return hose to the waste liquid tank.

[0004] (3) Next, the worker checks the color of the cleaning liquid being discharged into the waste tank, and when the cleaning liquid components increase, i.e., when the coloring from the paint becomes lighter, he moves the return hose to the cleaning liquid. The cleaning liquid then is sucked into the pump from the cleaning liquid tank via the suction hose and discharged back into the cleaning liquid tank via the return hose. In this way, the cleaning liquid is circulated between the cleaning liquid tank and the pump. (4) Then, after the cleaning liquid has been circulating for a certain period of time, the worker replaces the cleaning liquid in the cleaning liquid tank with new liquid and repeats step (3) above. (5) Then, he repeats steps (3) and (4) above several times, and finishes the work by confirming that the cleaning liquid discharged from the return hose is not stained with the color of the paint. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-262911 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the cleaning effect of the cleaning liquid was not fully achieved in the above-mentioned conventional configuration, which resulted in a large amount of cleaning liquid being used, increasing the cost of the cleaning liquid, and also reducing productivity due to the time required for cleaning.

[0007] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a positive displacement reciprocating pump unit 10 and an outside air intake device that can improve cleaning efficiency, reduce the amount of cleaning liquid used during cleaning work, and shorten the time required for cleaning. [Means for solving the problem]

[0008] The positive displacement reciprocating pump unit according to the embodiment includes a positive displacement reciprocating pump device having an inlet and an outlet for the liquid to be transferred, and a transfer path connecting the inlet and the outlet and through which the liquid to be transferred flows, and an outside air intake device provided on the inlet side that draws outside air into the transfer path by the negative pressure generated in the transfer path when the liquid to be transferred is transferred.

[0009] In addition, the outside air intake device according to the embodiment is connected to the inlet side of a positive displacement reciprocating pump device having an inlet and outlet for the liquid to be transferred, and a transfer path connecting the inlet and outlet and through which the liquid to be transferred flows, and takes in outside air into the transfer path by the negative pressure generated when the liquid to be transferred is transferred, and is equipped with an outside air intake port connecting the transfer path side to the outside, an outside air check valve that allows outside air to flow into the transfer path side through the outside air intake port and prohibits the liquid to be transferred on the transfer path side from flowing out to the outside through the outside air intake port, and an outside air opening / closing valve that opens and closes the outside air intake port. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram conceptually illustrating an example of the configuration of a coating system using a positive displacement reciprocating pump unit according to an embodiment. [Figure 2] FIG. 1 is a cross-sectional view of an example of a positive displacement reciprocating pump unit according to one embodiment, showing the pump device in a stopped state and the ambient air intake device in a closed state. [Figure 3] FIG. 1 is a diagram illustrating an example of an internal configuration of a pump chamber in an example of a positive displacement reciprocating pump unit according to an embodiment. [Figure 4] FIG. 1 is a cross-sectional view (part 1) illustrating an example of a positive displacement reciprocating pump unit according to an embodiment, in which the pump device is operated with the outside air intake device closed. [Figure 5] FIG. 2 is a cross-sectional view (part 2) illustrating an example of a positive displacement reciprocating pump unit according to an embodiment, in which the pump device is operated with the outside air intake device closed. [Figure 6] 6 is an enlarged cross-sectional view of the outside air intake device according to the embodiment, taken along the line X6-X6 of FIG. 2, showing the configuration of the connecting member and the outside air check valve and its surroundings. [Figure 7] 7 is a cross-sectional view showing an example of an outside air intake device according to an embodiment, in a state where the outside air check valve is open from the state shown in FIG. [Figure 8] FIG. 10 is a diagram showing the angular relationship between the receiving surface of the receiving member of the outside air check valve and the contact surface of the poppet in an example of an outside air intake device according to an embodiment; [Figure 9] FIG. 1 is a diagram conceptually illustrating an example of the configuration during cleaning of a coating system using a positive displacement reciprocating pump unit according to an embodiment. [Figure 10] 1 is a flowchart showing an example of a work flow during cleaning in a coating system using a positive displacement reciprocating pump unit according to an embodiment. [Figure 11] FIG. 1 is a cross-sectional view illustrating an example of a positive displacement reciprocating pump unit according to an embodiment, in which the pump device is operated with the outside air intake device open. [Figure 12] FIG. 10 is a diagram showing the cleaning effects of an example using an outside air intake device according to one embodiment and comparative examples 1 and 2 not using an outside air intake device. DETAILED DESCRIPTION OF THE INVENTION

[0011] A positive displacement reciprocating pump unit equipped with an outside air intake device according to one embodiment will be described below with reference to the drawings. FIG. 1 shows an example of an application of the positive displacement reciprocating pump unit 10 of the embodiment, in which the positive displacement reciprocating pump unit 10 is applied to a painting system. In this embodiment, the unit is configured by combining multiple devices. In this case, the devices constituting the unit can be configured to be separated and unusable, or can be configured to be separated and usable.

[0012] <Overall configuration of Painting System 1> First, the overall configuration of the coating system 1 shown in FIG. 1 will be described. The coating system 1 includes a drive source 2, a paint tank 3, a spray unit 4, a connection hose 5, and a positive displacement reciprocating pump unit 10. In the following description, the positive displacement reciprocating pump unit 10 may be simply referred to as the pump unit 10. The pump unit 10 is intended to transport cleaning liquids such as liquid paint and thinner. The drive source 2 supplies driving force for driving the pump unit 10. In this embodiment, the pump unit 10 is air-driven. Therefore, the drive source 2 is an air supply source such as a compressor. In addition, if the pump unit 10 is electrically driven using a motor or the like, the drive source 2 is composed of a power supply source such as a commercial power source or a battery.

[0013] The paint tank 3 is a tank for storing the material to be transported by the pump unit 10, in this case liquid paint. If the painting system 1 handles paint of multiple colors, the painting system 1 is provided with a paint tank 3 for each color. The spray unit 4 is for spraying the paint pressure-fed from the paint tank 3 by the pump unit 10 toward the object to be painted. The spray unit 4 may be, for example, a spray gun for manual painting, or may be attached to a robot or the like for automatic painting. The pump unit 10 and the spray unit 4 are connected by a connecting hose 5.

[0014] The pump unit 10 includes an air regulator 11, an air pressure gauge 12, an air valve 13, an air circuit 14, a suction hose 15, a paint regulator 16, a paint pressure gauge 17, a return hose 18, a paint valve 19, a pump device 20, and an outside air intake device 30. The pump device 20 is a positive displacement reciprocating pump. In this embodiment, the pump device 20 is configured as a diaphragm pump. Note that the pump device 20 is not limited to a diaphragm pump, and may be a piston pump, a bellows pump, a plunger pump, or the like.

[0015] The air regulator 11, air pressure gauge 12, and air valve 13 are provided between the drive source 2 and the pump device 20. The air regulator 11, air pressure gauge 12, and air valve 13 are arranged in this order from the drive source 2 side toward the pump device 20. The air regulator 11 is used to reduce and adjust the pressure of the air supplied from the drive source 2. The air pressure gauge 12 is used to display the pressure of the air supplied to the pump device 20 through the air regulator 11.

[0016] The air valve 13 is configured as, for example, a three-way ball valve, and is provided between the air regulator 11, the air pressure gauge 12, and the pump device 20. The air valve 13 is configured to be switchable among a state in which the drive source 2 and the pump device 20 are open to connect them, a state in which the pump device 20 is open to the atmosphere, and a state in which the drive source 2 and the pump device 20, the pump device 20 and the atmosphere, and the pump device 20 and the outside are all closed to isolate them from each other.

[0017] The driving source 2 is connected to an air circuit 14 provided in the pump device 20 via an air regulator 11, an air pressure gauge 12, and an air valve 13. The driving source 2 also branches off upstream of the air regulator 11 and is connected to a switching circuit (not shown) built into the pump device 20. A portion of the compressed air supplied from the driving source 2 is decompressed and adjusted through the air regulator 11, and then supplied to the air circuit 14.

[0018] Another portion of the compressed air supplied from the drive source 2 branches off upstream of the air regulator 11 and is supplied to a switching circuit (not shown) at its original pressure without being reduced in pressure. In this case, the air circuit 14 is configured, for example, by a two-position five-port air-operated valve, and supplies air for driving a diaphragm provided in the pump device 20. The switching circuit (not shown) is for inputting air to operate the air circuit 14, that is, air for switching the direction of air output from the air circuit 14, into the air circuit 14. Note that instead of the switching circuit (not shown), the air circuit 14 may be configured by a solenoid valve.

[0019] <Pump device 20> Next, details of the pump device 20 will be described. The pump device 20 has an inlet 21 and an outlet 22 for the paint to be transported, and draws paint into the pump device 20 from the inlet 21 and pumps the paint out from the outlet 22. A suction hose 15 is connected to the inlet 21 of the pump device 20. A paint regulator 16 and a paint pressure gauge 17 are connected to the outlet 22 of the pump device 20. The paint regulator 16 is used to reduce and adjust the pressure of the paint discharged from the outlet 22. The paint pressure gauge 17 is used to display the pressure of the paint that has been reduced and adjusted through the paint regulator 16. A portion of the paint that is pressure-fed from the outlet 22 of the pump device 20 is reduced and adjusted by the paint regulator 16 and supplied to the spray unit 4.

[0020] The return hose 18 is provided branching off from between the outlet 22 of the pump device 20 and the paint regulator 16. The paint valve 19 is configured as, for example, a two-way ball valve, and is provided between the return hose 18 and the outlet 22. The paint valve 19 is configured to be switchable between a state in which the return hose 18 and the outlet 22 are open to connect the two, and a state in which the return hose 18 and the outlet 22 are closed to block the connection between the two.

[0021] When painting is performed using the painting system 1, the air valve 13 connects the drive source 2 and the air circuit 14 of the pump device 20. The paint valve 19 connects the return hose 18 and the outlet 22. The suction hose 15 and the return hose 18 are both inserted into the paint tank 3.

[0022] In this state, when compressed air is supplied from the drive source 2 to the air circuit 14 and a switching circuit (not shown) provided in the pump device 20, the pump device 20 is driven. Then, the paint stored in the paint tank 3 is sucked into the pump device 20 from the inlet 21 via the suction hose 15, and then pressure-fed from the outlet 22. Then, when the spray unit 4 is operated, the paint is sprayed from the spray unit 4.

[0023] At this time, if paint is being sprayed from spray unit 4, the remaining paint that has not been sprayed from spray unit 4, or if paint is not being sprayed from spray unit 4, all of the paint that has been pressure-fed from outlet 22, is returned to paint tank 3 through return hose 18, and then is sucked again into pump device 20 through suction hose 15. In this way, when pump device 20 is operating, paint in paint tank 3 circulates via suction hose 15, pump device 20, and return hose 18, which prevents the paint from solidifying and forming sediment in paint tank 3.

[0024] 2, in addition to an inlet 21 and an outlet 22, the pump device 20 has a pump chamber 23, an air chamber 24, a variable mechanism 25, a suction path 26, a discharge path 27, a suction-side check valve 28, and a discharge-side check valve 29. In this embodiment, the pump device 20 has two pump chambers 23, two air chambers 24, two suction paths 26, and two discharge paths 27. The pump chambers 23, the air chambers 24, the suction paths 26, and the discharge paths 27 are provided inside the pump device 20 and arranged symmetrically.

[0025] The variable mechanism 25 receives a driving force and moves back and forth to vary the volume of each pump chamber 23, thereby changing the pressure inside each pump chamber 23. In this embodiment, the variable mechanism 25 is configured to have a diaphragm 251 and a shaft 252. The diaphragm 251 is configured from a thin circular plate made of, for example, resin or metal, and separates the pump chamber 23 from the air chamber 24. The shaft 252 connects the two diaphragms 251. This allows the two diaphragms 251 to operate in conjunction with each other.

[0026] Compressed air is alternately supplied and released from the drive source 2 to each air chamber 24 by the action of the air circuit 14 and a switching circuit (not shown). This causes the two diaphragms 251 to operate in conjunction with each other, reciprocating in the left-right direction in Figure 2. As a result, the volume of each pump chamber 23 is varied while the total volume of the two pump chambers 23 is maintained constant, thereby performing pumping operation.

[0027] Two suction paths 26 and two discharge paths 27 are provided corresponding to two pump chambers 23, respectively. The two suction paths 26 branch off near the inlet 21 and connect the inlet 21 to each pump chamber 23. Paint drawn in from the inlet 21 passes through the suction paths 26 and reaches the pump chamber 23. The two discharge paths 27 connect the pump chamber 23 to the outlet 22, respectively, and merge near the outlet 22. The suction paths 26 and the discharge paths 27 are paths through which the material to be transferred passes when it is transferred. Therefore, in the description of this embodiment, the suction paths 26 and the discharge paths 27 may be collectively referred to as transfer paths 26, 27.

[0028] 3, each pump chamber 23 is configured to have a circular shape when viewed in a plan view, that is, when viewed in a direction perpendicular to the surface of diaphragm 251. Furthermore, at least a portion of pump device 20 is made of a transparent member, and is configured so that the interior of at least one of pump chambers 23 can be seen from the outside of pump device 20. In this embodiment, pump device 20 has a body 201 and a flange 202. Body 201 is configured of, for example, a metal member.

[0029] The flange 202 is provided on the body 201 at a position corresponding to the pump chamber 23, and the pump chamber 23 is formed between the body 201 and the flange 202. In this embodiment, the flange 202 is made of a transparent material that is highly resistant to wear and chemicals, for example, transparent nylon, polycarbonate, or a so-called engineering plastic such as polyvinylidene chloride resin, or tempered glass. This makes it possible to see the inside of each pump chamber 23 from outside the pump device 20. It is not necessary to make the entire flange 202 from a transparent material. For example, the flange 202 may be made of metal, and a transparent material may be fitted into a portion of the flange 202 to provide a window through which the inside of each pump chamber 23 can be seen from outside the pump device 20.

[0030] Here, the connection portion between the suction path 26 and the pump chamber 23 is referred to as a tip end 261 of the suction path 26. Also, the connection portion between the pump chamber 23 and the discharge path 27 is referred to as a base end 271 of the discharge path 27. In this embodiment, the tip end 261 of the suction path 26 and the base end 271 of the discharge path 27 are provided at positions radially outward from the center P of the pump chamber 23 when viewed in a plan view and at positions inside the outermost diameter of the pump chamber 23. The tip end 261 of the suction path 26 and the base end 271 of the discharge path 27 are arranged so that the angle formed by the tip end 261 of the suction path 26, the center P of the pump chamber 23, and the base end 271 of the discharge path 27 is an acute angle.

[0031] The arrangement of the tip end 261 of the suction path 26 and the base end 271 of the discharge path 27 is not limited to the above. For example, the tip end 261 and the base end 271 may be arranged so that the angle formed by the tip end 261 of the suction path 26, the center P of the pump chamber 23, and the base end 271 of the discharge path 27 is an obtuse angle. Furthermore, the tip end 261 and the base end 271 may be arranged so that the tip end 261 of the suction path 26, the center P of the pump chamber 23, and the base end 271 of the discharge path 27 are on a straight line.

[0032] Pump device 20 has two suction-side check valves 28 and one discharge-side check valve 29. The two suction-side check valves 28 are each provided in suction path 26. Suction-side check valve 28 allows paint moving through suction path 26 to move from inlet 21 to pump chamber 23, and prohibits movement from pump chamber 23 to inlet 21. In other words, suction-side check valve 28 limits the movement direction of paint moving through suction path 26 to one direction, from inlet 21 to pump chamber 23, and prevents backflow of paint from pump chamber 23 to inlet 21.

[0033] In this embodiment, the suction side check valve 28 is a ball type and is configured to have a check ball 281. Note that the suction side check valve 28 is not limited to the ball type, and may be, for example, a poppet type, a swing type, a wafer type, a lift type, or a foot type.

[0034] The discharge-side check valve 29 is provided between the pump chamber 23 and the outlet 22. The discharge-side check valve 29 allows paint moving through each discharge path 27 to move from the pump chamber 23 side to the outlet 22 side, but prohibits movement from the outlet 22 side to the pump chamber 23 side. In other words, the discharge-side check valve 29 limits the movement direction of paint moving through the discharge path 27 to one way, from the pump chamber 23 side to the outlet 22 side, and prevents backflow of paint from the outlet 22 side to the pump chamber 23 side.

[0035] In this embodiment, one discharge-side check valve 29 corresponds to two discharge paths 27. The discharge-side check valve 29 is provided at a junction 221 where the two discharge paths 27 join. In this case, the discharge-side check valve 29 is a ball type and includes a check ball 291. Here, the connection portion between each discharge path 27 and the junction 221 is defined as a tip 272 of the discharge path 27. The check ball 291 closes one of the two tip portions 272 and opens the other. This allows the discharge-side check valve 29 to connect one of the two discharge paths 27 to the outlet 22 side and close the other. Note that the suction-side check valve 28 is not limited to a ball type and may be, for example, a poppet type, a swing type, a wafer type, a lift type, or a foot type.

[0036] In this configuration, as shown in Fig. 4, when compressed air is supplied to one of the two air chambers 24 (in this case, the right air chamber 24 in Fig. 4) and the other, the left air chamber 24, is opened to the atmosphere, the right diaphragm 251 is pushed by the compressed air and moves, reducing the volume of the right pump chamber 23. The movement of the right diaphragm 251 is transmitted to the left diaphragm 251 via the shaft 252. The left diaphragm 251 then moves in conjunction with the left diaphragm 251, increasing the volume of the left pump chamber 23. As a result, the pressure in the right pump chamber 23 increases and the pressure in the left pump chamber 23 decreases.

[0037] At this time, the pressure in the right pump chamber 23 increases and the pressure in the left pump chamber 23 decreases, so that paint is sucked into the left pump chamber 23 from the inlet 21, as shown by the white arrow in Figure 4. Also, at this time, the check ball 291 of the discharge-side check valve 29 moves toward the tip 272 of the left discharge path 27, closing the tip 272 of the left discharge path 27.

[0038] Next, when the direction of the compressed air discharged from the air circuit 14 is switched by a switching circuit (not shown), and the right air chamber 24 is opened to the atmosphere and compressed air is supplied to the left air chamber 24 as shown in Figure 5, the reverse of the above-mentioned operation occurs. That is, in this case, the volume of the right pump chamber 23 increases and the volume of the left pump chamber 23 decreases. As a result, the pressure in the right pump chamber 23 decreases and the pressure in the left pump chamber 23 increases.

[0039] At this time, the check ball 291 of the discharge-side check valve 29 is pushed by the paint flowing from the left discharge path 27 and is sucked in by the negative pressure in the right pump chamber 23, so that it moves toward the tip 272 of the right discharge path 27 and closes the tip 272 of the right discharge path 27. In other words, the right discharge path 27 is connected to the outlet 22. Therefore, as shown by the black arrow in FIG. 5, the paint flowing out from the left pump chamber 23 is pumped out from the outlet 22. Also, at this time, the pressure in the right pump chamber 23 decreases, so that paint is sucked into the right pump chamber 23 from the inlet 21, as shown by the white arrow in FIG. 5. Then, by repeating the above operation, the paint sucked in from the inlet 21 is continuously discharged from the outlet 22.

[0040] <Outside air intake device 30> Next, the details of the outside air intake device 30 will be described. The outside air intake device 30 is a device that takes in outside air into the intake path 26 by using negative pressure generated in the intake path 26 when the pump device 20 is operated to transfer a transfer target such as a cleaning liquid. In this embodiment, outside air refers to the air outside the pump device 20, i.e., the atmosphere. The outside air intake device 30 is provided on the upstream side of the transfer paths 26, 27 of the pump device 20, in this case, at the inlet 21. The outside air intake device 30 can be configured to be detachable from the pump device 20. That is, the outside air intake device 30 can be configured to be retrofittable to an existing pump device, for example. Alternatively, the outside air intake device 30 can be configured to be permanently attached to the pump device 20.

[0041] 2, the outside air intake device 30 has a connecting member 40, an outside air check valve 50, a flow rate adjustment valve 60, and an outside air on-off valve 70. The connecting member 40 is provided between the suction hose 15 and the inlet 21 of the pump device 20, and connects the suction hose 15 and the inlet 21.

[0042] The connecting member 40 has a connection path 41 and a communication section 42. The connection path 41 is formed through the inside of the connecting member 40 and connects the suction hose 15 and the suction path 26. The object to be transferred that has passed through the suction hose 15 is sucked into the suction path 26 via the connection path 41. The connecting member 40 can also be configured as a part of the inlet 21. In other words, the outside air check valve 50 can be directly attached to the inlet 21.

[0043] The communication portion 42 is provided, for example, in a middle portion of the connection path 41, and is formed to penetrate the connection member 40. The communication portion 42 communicates the inside of the connection member 40, i.e., the connection path 41, with the outside of the connection member 40.

[0044] The outside air check valve 50 is connected to the communication part 42 and has an outside air intake port 511. The outside air intake port 511 is located inside the communication part 42 and connects the suction path 26 side, in this case the connection path 41, to the outside. The outside air check valve 50 has the function of allowing outside air to flow into the connection path 41 through the outside air intake port 511. The outside air check valve 50 also has the function of prohibiting the material flowing through the connection path 41 from flowing out of the connection path 41, i.e., to the atmosphere, through the outside air intake port 511. In other words, the outside air check valve 50 has the function of taking in outside air into the connection path 41 and preventing the material in the connection path 41 from flowing back to the atmosphere.

[0045] As shown in FIG. 6 , the extension direction of the connection path 41 intersects with the extension direction of the outside air intake 511. The outside air intake 511 is offset with respect to the connection path 41. That is, if a line passing through the radial center of the connection path 41 and extending in the extension direction of the connection path 41 is defined as a center line J1 of the connection path 41, and a line passing through the radial center of the outside air intake 511 and extending in the extension direction of the outside air intake 511 is defined as a center line J2 of the outside air intake 511, the center line J2 of the outside air intake 511 is shifted outward in the radial direction of the connection path 41 with respect to the center line J1 of the connection path 41. As a result, as shown by the solid line in FIG. 7 , air taken into the connection path 41 from the outside air intake 511 flows along the outer periphery of the connection path 41, making it easier for a swirling flow to occur within the connection path 41.

[0046] The outside air check valve 50 has a receiving member 51, a poppet 52, and an elastic member 53. The receiving member 51 is a member having an outside air intake port 511, and is attached by being fitted into the communication portion 42 of the connecting member 40, for example.

[0047] The receiving member 51 is made of a metal such as stainless steel and is formed in a stepped cylindrical shape. The outside air intake port 511 is formed by penetrating the receiving member 51 in the axial direction of the cylindrical shape. The receiving member 51 also has a receiving surface 512. The receiving surface 512 is part of the inner surface of the outside air intake port 511 and is the surface that comes into contact with the tip of the poppet 52. The receiving surface 512 is formed in a conical shape that widens toward the connection path 41 side.

[0048] The poppet 52 is made of a material, such as resin, that has lower rigidity than the receiving member 51. As shown in Figures 6 and 7, the poppet 52 is configured to be movable in directions toward and away from the receiving member 51. The poppet 52 closes the outside air intake port 511 by coming into contact with and tightly fitting to the receiving surface 512 of the receiving member 51. The poppet 52 also opens the outside air intake port 511 by moving away from the receiving surface 512 of the receiving member 51.

[0049] Poppet 52 is formed into a cylindrical rod shape overall. As shown in Fig. 6 and other figures, when the receiving member 51 side of poppet 52 is the tip side and the opposite side to receiving member 51 is the base end side, the tip portion of poppet 52 is formed into a bulging shape. Poppet 52 has contact surface 521 on the outer circumferential surface of the tip portion. Contact surface 521 is the portion that comes into contact with receiving surface 512 when poppet 52 closes outside air inlet 511. Contact surface 521 is formed into a conical surface that narrows toward outside air inlet 511.

[0050] An elastic force is constantly applied to poppet 52 toward fresh air inlet 511 by elastic member 53 formed of a coil spring or the like. When the pressure difference between the outside and inside of connection path 41 across fresh air inlet 511 is smaller than the elastic force of elastic member 53, poppet 52 is pressed against contact surface 521 by the elastic force of elastic member 53, blocking fresh air inlet 511, as shown in Fig. 6. On the other hand, when the pressure difference between the outside and inside of connection path 41 across fresh air inlet 511 becomes larger than the elastic force of elastic member 53, poppet 52 is pushed in a direction away from fresh air inlet 511 by the pressure outside connection path 41, opening fresh air inlet 511, as shown in Fig. 7.

[0051] Here, since the receiving member 51 is made of a metal such as stainless steel and the poppet 52 is made of a resin, the poppet 52 wears out as it repeatedly comes into contact with the receiving member 51. In other words, the poppet 52 is a consumable item. Therefore, the angle θ1 of the receiving surface 512 of the receiving member 51 with which the poppet 52 comes into contact and the angle θ2 of the contact surface 521 of the poppet 52 with which the receiving surface 512 comes into contact are set to different angles.

[0052] According to this, the outer peripheral edge of either receiving surface 512 or contact surface 521 is in line contact with the other surface rather than in surface contact. Therefore, even if poppet 52 wears, receiving surface 512 and contact surface 521 are in line contact, so sealing performance can be maintained. As a result, the life of poppet 52 can be extended, and the parts cost of poppet 52 and the man-hours required for replacing poppet 52 can be reduced.

[0053] The angle θ1 of the receiving surface 512 can be set to a value larger than the angle θ2 of the contact surface 521, for example. In this case, the angle θ1 of the receiving surface 512 is set within a range of 65°±10°, for example. On the other hand, the angle θ2 of the contact surface 521 is set to an angle within a range of 60°±10° and smaller than the angle θ1 of the receiving surface 512. Furthermore, the angle θ1 of the receiving surface 512 may be set to a value smaller than the angle θ2 of the contact surface 521, for example.

[0054] The flow rate adjustment valve 60 is provided between the outside air check valve 50 and the outside air on-off valve 70 and is configured to adjust the amount of air, i.e., outside air, passing through the outside air check valve 50. The inflow side, i.e., the upstream side, of the flow rate adjustment valve 60 is connected to the outside air on-off valve 70, and the outflow side, i.e., the downstream side, is connected to the receiving member 51 of the outside air check valve 50. The flow rate adjustment valve 60 may be configured, for example, as a needle valve having a needle 61. In this case, an operator can manually adjust the amount of air passing through the flow rate adjustment valve 60 by rotating the needle 61. Note that the flow rate adjustment valve 60 is not limited to a manual type and may be an electrically or air-driven adjustment valve that is driven under external control.

[0055] The outside air on-off valve 70 is provided upstream of the flow rate adjustment valve 60. The outside air on-off valve 70 has the function of opening and closing the outside air intake port 511. The outside air on-off valve 70 may be configured, for example, as a ball cock. In this case, the outside air on-off valve 70 may be configured, for example, with a valve seat 71, a spherical valve body 72, a handle 73, and a filter 74. The filter 74 may be configured, for example, as a perforated plate with many small holes formed therein, preventing foreign matter from entering the outside air on-off valve 70. An operator can manually start and stop the intake of outside air into the pump device 20 by operating the handle 73 to open and close the outside air on-off valve 70. Note that the outside air on-off valve 70 is not limited to a manual type and may be an electric or air-driven on-off valve that is driven under external control.

[0056] <How to clean the pump equipment> Next, a method for cleaning the pump device 20 will be described with reference to Figures 9 to 11. In the cleaning method of this embodiment, the transfer paths 26 and 27 of the pump device 20 are primarily cleaned, but other paint paths, namely the suction hose 15, the return hose 18, and the spray unit 4, are also cleaned. When cleaning the pump device 20, an operator uses a cleaning liquid tank 7 and a waste liquid tank 8, as shown in Figure 9. The cleaning liquid tank 7 stores an organic solvent, such as thinner, as a cleaning liquid. The waste liquid tank 8 stores the cleaning liquid that has been discharged after cleaning the pump device 20. In this case, the drive source 2, the cleaning liquid tank 7, and the waste liquid tank 8 are components of a cleaning system for the pump device 20.

[0057] When cleaning the pump device 20, the worker first performs the work of discharging paint remaining in the pump device 20 to the outside of the pump device 20 in step S11 of Fig. 10. In step S11, the worker opens the air valve 13 and the paint valve 19 to operate the pump device 20. Then, while the pump device 20 is operating, the worker pulls out the suction hose 15 from the paint tank 3 to suck in air, and discharges the remaining paint remaining in the pump device 20 from the return hose 18 to the paint tank 3.

[0058] Next, in step S12 shown in Fig. 10, the worker opens the outside air on-off valve 70 as shown in Fig. 11. This enables the pump device 20 to take in outside air into the pump device 20 by operating the pump device 20. Next, in step S13, the worker draws in and discharges cleaning liquid into the pump device 20 with the outside air on-off valve 70 open. In this case, the worker moves the suction hose 15 to the cleaning liquid tank 7 and moves the return hose 18 to the waste liquid tank 8 as shown in Fig. 9. Then, the worker operates the pump device 20 to draw in the cleaning liquid in the cleaning liquid tank 7 into the pump device 20 and discharge the drawn-in cleaning liquid into the waste liquid tank 8.

[0059] At this time, the connection path 41 and the suction path 26 are put under negative pressure by the operation of the pump device 20, and therefore, as shown by the solid arrows in Figure 11, outside air is taken into the connection path 41 and the suction path 26 via the outside air on-off valve 70, the flow rate adjustment valve 60, and the outside air check valve 50. The outside air intake device 30 intermittently takes in outside air in accordance with the reciprocation of the variable flow mechanism 25. As a result, the outside air becomes fine bubbles and is mixed into the cleaning liquid flowing through the transfer paths 26 and 27. This outside air intermittently taken into the cleaning liquid acts as so-called bubbling, which enhances the cleaning effect of the cleaning liquid, similar to when an operator inserts and removes the suction hose 15 into the cleaning liquid tank 7.

[0060] In the initial stage when the suction of the cleaning liquid begins, a large amount of paint still remains in the pump device 20, so the discharged liquid discharged from the return hose 18 contains a large amount of paint components, but as the cleaning liquid suction process continues, the proportion of the cleaning liquid components gradually increases. Then, in step S14, the operator checks the transparency of the cleaning liquid discharged from the return hose 18, for example, visually. Then, if the transparency of the discharged cleaning liquid is insufficient, that is, if the discharged cleaning liquid is still colored by paint (NG in step S14), the operator replaces the cleaning liquid in the cleaning liquid tank 7 with new, clean cleaning liquid in step S15. The operator repeats steps S13 to S14 until the transparency of the discharged liquid discharged from the return hose 18 reaches a predetermined level.

[0061] In step S13, the operator may insert the return hose 18 into the cleaning liquid tank 7. In this way, the cleaning liquid in the pump device 20 is discharged from the return hose 18 into the cleaning liquid tank 7, and the cleaning liquid in the cleaning liquid tank 7 is sucked into the pump device 20 via the suction hose 15. This causes the cleaning liquid to circulate between the cleaning liquid tank 7 and the pump device 20, making it possible to reduce the amount of cleaning liquid used compared to when the cleaning liquid is continuously discharged.

[0062] Then, when the worker confirms in step S14 that the cleaning liquid discharged is sufficiently transparent, that is, that the liquid discharged from the return hose 18 is not stained with the color of the paint (OK in step S14), he closes the outside air on-off valve 70 and stops the operation of the pump device 20 in step S16, thereby completing the series of cleaning operations. Note that, apart from the above cleaning operations, the worker can also clean the spray unit 4 and the connection hose 5 by spraying cleaning liquid from the spray unit 4.

[0063] <Explanation of cleaning effect> Next, the cleaning effect of this embodiment will be described in comparison with Comparative Examples 1 and 2 with reference to FIG. 12 . In FIG. 12 , the example indicated by a white square shows the cleaning effect when a positive displacement reciprocating pump unit 10 equipped with an outside air intake device 30 was cleaned using the above-described cleaning method. In FIG. 12 , Comparative Example 1 indicated by a white circle shows the cleaning effect when a positive displacement reciprocating pump unit 10 not equipped with an outside air intake device 30 was cleaned without inserting or removing the suction hose 15 into or from the cleaning liquid tank 7, i.e., without bubbling. In FIG. 12 , Comparative Example 2 indicated by a black circle shows the cleaning effect when a positive displacement reciprocating pump unit 10 not equipped with an outside air intake device 30 was cleaned with inserting or removing the suction hose 15 into or from the cleaning liquid tank 7, i.e., with bubbling.

[0064] In the graph of Figure 12, the vertical axis represents the change in transparency of the discharged cleaning liquid, and the horizontal axis represents the amount of cleaning liquid used to reach that transparency. Here, the transparency of the discharged cleaning liquid refers to the transparency of the discharged cleaning liquid, i.e., its transmittance to visible light.

[0065] In the Example and Comparative Examples 1 and 2, when looking at the amount of cleaning fluid required to reach 80% transparency of the discharged cleaning fluid, the amount of cleaning fluid used in the Example is approximately 40% of the amount of cleaning fluid used in Comparative Example 1, and approximately 80% of the amount of cleaning fluid used in Comparative Example 2. In other words, the amount of cleaning fluid used in the Example can be reduced by approximately 60% compared to the amount of cleaning fluid used in Comparative Example 1, and can be reduced by approximately 20% compared to the amount of cleaning fluid used in Comparative Example 2.

[0066] According to the embodiment described above, the positive displacement reciprocating pump unit 10 includes a positive displacement reciprocating pump device 20 and an outside air intake device 30. The pump device 20 has an inlet 21 and an outlet 22 for the liquid to be transferred, and an intake path 26 and a discharge path 27 that connect the inlet 21 and the outlet 22 and serve as transfer paths through which the liquid to be transferred flows. The outside air intake device 30 is provided on the inlet 21 side, and takes outside air into the intake path 26, which serves as a transfer path, by using negative pressure generated in the intake path 26 when the liquid to be transferred is transferred.

[0067] This allows outside air to be introduced into the cleaning liquid when cleaning the pump device 20 using a cleaning liquid such as thinner. This intake of outside air creates a so-called bubbling effect, similar to the operation of an operator inserting and removing the suction hose 15 into the cleaning liquid tank 7, and can improve the cleaning effect of the cleaning liquid. In addition, the operator no longer needs to insert and remove the suction hose 15 into the cleaning liquid tank 7 to achieve the bubbling effect of the cleaning liquid, simplifying the work. This reduces the amount of cleaning liquid used, resulting in reduced cleaning costs and improved productivity due to shorter cleaning times.

[0068] The outside air intake device 30 has an outside air check valve 50 and an outside air on-off valve 70. The outside air check valve 50 has an outside air inlet 511 that connects the suction path 26 side with the outside. The outside air check valve 50 allows outside air to flow through the outside air inlet 511 into the suction path 26 side, in this case, into the connecting path 41. The outside air check valve 50 also prohibits paint or cleaning liquid on the transfer path 26 side, in this case, the connecting path 41, from flowing out to the outside through the outside air inlet 511. The outside air on-off valve 70 opens and closes the outside air inlet 511.

[0069] With this, even if the worker opens the outside air on-off valve 70, the outside air check valve 50 can prevent the paint or cleaning liquid inside the pump device 20 from flowing back to the outside through the outside air inlet 511. This makes it possible to suppress pollution of the external environment caused by the paint or cleaning liquid inside the pump device 20 leaking out through the outside air inlet 511. Furthermore, with this, a so-called bubbling effect can be achieved by opening and closing the outside air on-off valve 70 without using a pneumatic device such as a compressor. As a result, it is possible to suppress increases in CO2 emissions and energy consumption that would be associated with the intake of outside air.

[0070] This configuration also simplifies the work process by eliminating the need for the worker to frequently check whether paint or cleaning agent has leaked from the outside air intake device 30. Furthermore, by properly taking in outside air using the outside air check valve 50, the pressure inside the pump device 20 is maintained at an appropriate level, thereby extending the life of the pump device 20.

[0071] The outside air intake device 30 also has a flow rate adjustment valve 60. The flow rate adjustment valve 60 is provided between the outside air check valve 50 and the outside air on-off valve 70, and is configured to be able to adjust the amount of air passing through the outside air check valve 50. This allows the operator to adjust the amount of outside air taken in from the outside air intake device 30 to an appropriate amount depending on the state of dirt inside the pump device 20. As a result, the cleaning efficiency can be further improved.

[0072] The outside air check valve 50 has a metal receiving member 51 having an outside air inlet 511, and a resin poppet 52. The poppet 52 is configured to be movable toward and away from the receiving member 51, and comes into contact with the receiving member 51 to close the outside air inlet 511, and moves away from the receiving member 51 to open the outside air inlet 511. An angle θ1 of a receiving surface 512 of the receiving member 51 with which the poppet 52 comes into contact is set to be different from an angle θ2 of a contact surface 521 of the poppet 52 with which the receiving surface 512 comes into contact.

[0073] According to this, the outer peripheral edge of either receiving surface 512 or contact surface 521 is in line contact with the other surface rather than in surface contact. Therefore, even if poppet 52 wears, receiving surface 512 and contact surface 521 are in line contact, so sealing performance can be maintained. As a result, the life of poppet 52 can be extended, and the parts cost of poppet 52 and the man-hours required for replacing poppet 52 can be reduced.

[0074] The fresh air intake device 30 further has a connecting member 40. The connecting member 40 is connected to the inlet 21 of the pump device 20 to connect the inlet 21 and the suction hose 15. The connecting member 40 has a connection path 41 that connects the suction path 26 and the suction hose 15, and an fresh air intake port 511 is provided in the middle of the connection path 41. A center line J1 that passes through the radial center of the fresh air intake port 511 and extends in the extension direction of the fresh air intake port 511 is set at a position shifted outward with respect to a center J2 of the connection path 41 in the radial direction.

[0075] 7, the air taken into the connecting path 41 from the outside air intake port 511 flows along the outer periphery of the connecting path 41, which makes it easier to generate a swirling flow within the connecting path 41. As a result, the swirling flow can more effectively clean the inner wall of the connecting path 41, the inner wall of the suction path 26 located downstream of the connecting path 41, and the like.

[0076] The above-described embodiments are not limited to the embodiments described above and illustrated in the drawings, and may be modified as appropriate within the scope of the invention. The above embodiment can also be applied to any pump that has two or more pump chambers and is configured to change the volume of each pump chamber by reciprocating motion to pump material, such as a piston pump, a bellows pump, or a plunger pump. [Explanation of symbols]

[0077] 10...positive displacement reciprocating pump unit, 15...suction hose, 20...pump device, 21...inlet, 22...outlet, 26...transfer path, suction path, 27...transfer path, discharge path, 30...outside air intake device, 40...connecting member, 41...connecting path, 50...outside air check valve, 51...receiving member, 511...outside air intake port, 512...receiving surface, 521...contact surface, 52...poppet, 60...flow rate adjustment valve, 70...outside air on-off valve, J1...center line, J2...center line

Claims

1. a positive displacement reciprocating pump device having an inlet and an outlet for a liquid to be transferred, and a transfer path connecting the inlet and the outlet and through which the liquid to be transferred flows; an outside air intake device provided on the inlet side that takes in outside air into the transfer path by negative pressure generated in the transfer path when the transfer object is transferred; A positive displacement reciprocating pump unit comprising:

2. The outside air intake device is an outside air check valve having an outside air intake port connecting the transfer path side and the outside, allowing outside air to flow into the transfer path side through the outside air intake port and prohibiting the transfer object on the transfer path side from flowing out to the outside through the outside air intake port; and an outside air on-off valve that opens and closes the outside air intake port.

2. The positive displacement reciprocating pump unit according to claim 1.

3. The outside air intake device is a flow rate adjusting valve provided between the outside air check valve and the outside air on-off valve, the flow rate adjusting valve being capable of adjusting the amount of air passing through the outside air check valve; 3. The positive displacement reciprocating pump unit according to claim 2.

4. The outside air check valve is a metal receiving member having the outside air intake; a resin poppet that is made of resin and is configured to be movable in a direction toward and away from the receiving member, and that comes into contact with the receiving member to close the outside air intake port and moves away from the receiving member to open the outside air intake port; An angle of a receiving surface of the receiving member with which the poppet comes into contact is different from an angle of a contact surface of the poppet with which the poppet comes into contact with the receiving surface.

4. A positive displacement reciprocating pump unit according to claim 2 or 3.

5. the outside air intake device further includes a connecting member connected to the inlet of the pump device and connecting the inlet to a suction hose; The connecting member is a connection path that connects the transfer path and the suction hose, and the outside air intake port is provided in a middle portion of the connection path; a center line passing through a radial center of the outside air intake port and extending in an extension direction of the outside air intake port is set at a position shifted outward with respect to a radial center of the connection path; 4. A positive displacement reciprocating pump unit according to claim 2 or 3.

6. a positive displacement reciprocating pump device having an inlet and an outlet for a liquid to be transferred, and a transfer path connecting the inlet and the outlet and through which the liquid to be transferred flows; and a pump connected to the inlet side of the positive displacement reciprocating pump device, wherein negative pressure generated when the liquid to be transferred is transferred causes outside air to be drawn into the transfer path; an outside air check valve having an outside air intake port connecting the transfer path side and the outside, allowing outside air to flow into the transfer path side through the outside air intake port and prohibiting the transfer object on the transfer path side from flowing out to the outside through the outside air intake port; an outside air on-off valve that opens and closes the outside air intake; An outside air intake device comprising:

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