JP2023020185A - Liquid supply device - Google Patents

Abstract

To enhance discharge accuracy of liquid in a liquid supply device.SOLUTION: A liquid supply device injects liquid into a pump chamber 16 by expanding a tubephragm 15 as first flexible member, discharges the liquid in the pump chamber 16 to the outside by contracting the tubephragm 15, and comprises a medium housing case 28 comprising a bellows 31 as a second flexible member for separating a medium housing chamber 32 communicating with a pump housing chamber 17 and an air chamber 33, a drive mechanism 27 provided with a rod 44a, an electric motor 46 as a drive member for reciprocating the rod 44a in an axial direction, and a pressure adjustment mechanism 60 for reducing a pressure in the air chamber 33 when expanding the tubephragm 15 via a liquid medium M by contracting the bellows 31.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid supply device for supplying liquid to an object to be coated.

In the technical fields of semiconductor integrated circuit devices and liquid crystal panels, liquid supply devices are used to supply liquids such as photoresist liquids to objects to be coated. is used to supply electrolyte to the inside of the battery container.

As described in Patent Document 1, such a liquid supply device includes a pump case in which a tube frame as a flexible member that is elastically deformable in the radial direction is incorporated, and a flexible tube that is elastically deformable in the axial direction. Some have a bellows case in which a bellows as an elastic member is incorporated. A primary port of the pump chamber in the tubeflam is connected to the liquid tank, and a secondary port of the pump chamber is connected to the liquid discharge. The pump housing chamber in the pump case and the medium housing chamber in the bellows case are communicated with each other and filled with a liquid medium made of an incompressible liquid. It expands and contracts, and the liquid in the liquid tank is discharged from the liquid discharger.

JP 2012-162269 A

As described in Patent Literature 1, it has a tubeflam incorporated in a pump case and a bellows incorporated in a bellows case, and the expansion and contraction of the bellows causes the tubephragm to pump through a liquid medium. In such a liquid supply device, the bellows is contracted when liquid is drawn into the pump chamber within the tube. As a result, the liquid medium in the pump housing chamber of the pump case is sucked into the medium housing chamber in the bellows case, and the tubeflam expands in the radial direction. On the other hand, when the liquid sucked into the pump chamber is discharged to the liquid discharge portion, the bellows is extended. As a result, the liquid medium in the medium storage chamber in the bellows case is supplied into the pump storage chamber in the pump case, and the tube frame is contracted. Thus, in a liquid supply device with two flexible members, pumping action is performed by both flexible members.

A positive pressure is applied by the liquid medium to the outer surface of the bellows bellows when liquid is discharged from the pumping chamber by extending the bellows and contracting the tubeflam through the liquid medium. On the other hand, as the volume inside the bellows portion increases, the inner surface of the bellows portion becomes in a negative pressure state. When the pressure difference between the positive pressure on the outer surface of the bellows portion and the negative pressure on the inner surface of the bellows portion exceeds a predetermined value, the outer diameter of the bellows portion is deformed to decrease. On the other hand, when pumping liquid into the pump chamber by contracting the bellows and expanding the tube through the liquid medium, the outer surface of the bellows bellows is in a negative pressure state. On the other hand, a positive pressure is applied to the inner surface of the bellows portion by reducing the volume inside the bellows portion. When the pressure difference between the negative pressure on the outer surface of the bellows portion and the positive pressure on the inner surface of the bellows portion exceeds a predetermined value, the outer diameter of the bellows portion is deformed to increase.

For this reason, when the tubeflam is contracted and the liquid is discharged from the pump chamber to the outside, the discharge amount corresponding to the extension stroke of the bellows differs from the set value, and when the tubephragm is expanded and the liquid is injected into the pump chamber In addition, it is conceivable that the intake amount corresponding to the contraction stroke of the bellows differs from the set value. If the effective diameter of the bellows portion in the radial direction differs between when the bellows is expanded and when it is contracted, the liquid cannot be discharged from the pump chamber toward the liquid discharge port with high precision. the ejection accuracy of the ink drops.

Further, when the bellows is contracted to inject liquid into the pump chamber, if the pressure on the outer surface of the bellows portion is lower than that on the inner surface, the air in the air chamber inside the bellows portion passes through the bellows made of resin material to form a liquid medium. may be mixed into If air is mixed in the liquid medium, the accuracy of discharging the liquid from the pump chamber is lowered. Such a drop in discharge accuracy may also occur in a liquid supply device that performs a pumping operation using a bellows or diaphragm as a flexible member that separates a pump chamber from an air chamber.

SUMMARY OF THE INVENTION It is an object of the present invention to suppress an increase in the pressure difference between the inside and outside of a flexible member in a liquid supply device that performs a pumping operation using a flexible member, thereby improving the accuracy of liquid ejection.

One form of the liquid supply device includes a first flexible member arranged in a pump case to separate a pump chamber and a pump housing chamber, and increases the volume of the pump chamber to inject liquid into the pump chamber. and a liquid supply device for reducing the volume of the pump chamber and discharging the liquid in the pump chamber to the outside, wherein a second flexible material partitions a medium storage chamber communicating with the pump storage chamber and an air chamber. a medium containing case provided with a member; a pump containing chamber and a liquid medium filled in the medium containing chamber; a driving member that reciprocates in a discharge direction for supplying the liquid medium and an injection direction for returning the liquid medium from the pump storage chamber to the medium storage chamber; and driving the rod in the injection direction to reduce the volume of the air chamber. and a pressure adjustment mechanism that reduces the pressure of the air chamber when the air chamber is closed.

Another form of the liquid supply device includes a flexible member arranged in a pump case to separate a pump chamber and an air chamber, and increasing the volume of the pump chamber to inject liquid into the pump chamber, In the liquid supply device for reducing the volume of the pump chamber and discharging the liquid in the pump chamber to the outside, the rod attached to the flexible member is aligned with the discharge direction for discharging the liquid in the pump chamber to the outside. a driving member that reciprocates in the injection direction of injecting liquid into the pump chamber; and a pressure adjustment mechanism that reduces the pressure of the air chamber when the rod is moved in the injection direction and the volume of the air chamber is reduced. , has

In a liquid supply device that performs a pumping operation using first and second flexible members, when the volume of the pump chamber is increased by the first flexible member to inject liquid into the pump chamber, the second flexible member is used. The pressure in the medium containing chamber in contact with the outer surface of the flexible member is reduced. On the other hand, the pressure in the air chamber, which is in contact with the inner surface of the second flexible member, is lowered by the pressure adjustment mechanism in accordance with the pressure in the medium storage chamber or the contraction of the second flexible member. As a result, the pressure difference between the medium storage chamber and the air chamber is reduced, so that it is possible to prevent the air in the air chamber from penetrating the second flexible member and entering the medium drive chamber. Excessive deformation in the direction of increasing the volume is suppressed, and the pump characteristics can be maintained with high accuracy over a long period of time.

In a liquid supply device in which a flexible member that partitions a pump chamber and an air chamber performs a pumping operation, when the volume of the pump chamber is increased to inject liquid into the pump chamber, the pressure in the pump chamber increases with respect to the air chamber. However, the pressure in the air chamber is lowered by the pressure adjustment mechanism to correspond to the pressure in the pump chamber. As a result, the pressure difference between the pump chamber and the air chamber is reduced, so that the air in the air chamber can be prevented from permeating the flexible member and entering the medium driving chamber, and the volume of the air chamber is increased. Excessive deformation in the direction is suppressed, and the pump characteristics can be maintained with high accuracy for a long period of time.

FIG. 4 is a cross-sectional view showing the liquid supply device according to one embodiment, showing a state in which the tube flamm as the first flexible member is radially expanded to inject the liquid into the pump chamber. FIG. 4 is a cross-sectional view showing the liquid supply device in a state in which the tube flamm is contracted in the radial direction and the liquid is discharged from the pump chamber to the outside. FIG. 3 is an enlarged sectional view showing the pressure regulating piston shown in FIGS. 1 and 2; FIG. 5 is a cross-sectional view showing a liquid supply device of another embodiment; 5 is a pneumatic circuit diagram of the pneumatic control device shown in FIG. 4; FIG. FIG. 5 is a cross-sectional view showing a liquid supply device of another embodiment; FIG. 9 is a cross-sectional view showing a liquid supply device according to still another embodiment; FIG. 8 is a pneumatic circuit diagram of the pressure adjustment mechanism in the liquid supply device shown in FIGS. 6 and 7;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The liquid supply device 10a shown in FIGS. 1 to 3 includes a pump 11 and a pump drive unit 12. As shown in FIG. The pump 11 has a pump case 14 formed with a housing hole 13 extending longitudinally therethrough, and a tube frame 15 as a first flexible member is arranged in the pump case 14 . The tube frame 15 is a flexible pump member that is made of a resin material such as fluororesin and that is elastically deformable in the radial direction. It is partitioned into an inner pump chamber 16 and an outer pump housing chamber 17 by a tube flam 15 . An inflow joint 18 is provided at one end of the pump case 14 and an outflow joint 19 is provided at the other end of the pump case 14 .

When the inflow joint 18 is connected to the liquid tank 22 through the inflow pipe 21 and the outflow joint 19 is connected to the liquid discharger 24 through the outflow pipe 23, the liquid L in the liquid tank 22 is discharged from the liquid discharger 24. be able to. The liquid ejected from the liquid ejection part 24 is supplied to an object to be coated (not shown). The liquid L in the liquid tank 22 is injected into the pump chamber 16 when the tubeflam 15 expands radially to increase the volume of the pump chamber 16 , and the tubeflam 15 radially contracts to increase the volume of the pump chamber 16 . When the volume is reduced, the liquid L in the pump chamber 16 is discharged to the outside toward the liquid discharge portion 24 .

A check valve 25 is provided in the inflow pipe 21 . The check valve 25 allows the liquid L in the liquid tank 22 to flow toward the pump chamber 16 through the inflow pipe 21 when the volume of the pump chamber 16 is increased. is reduced, the liquid in the inflow side pipe 21 is prevented from flowing back to the liquid tank 22.例文帳に追加A check valve 26 is provided in the outflow pipe 23 . When the volume of the pump chamber 16 is reduced, the check valve 26 allows the liquid L in the pump chamber 16 to flow toward the liquid discharge section 24 via the outflow pipe 23, and the volume of the pump chamber 16 is reduced. is increased, the backflow of the liquid L in the outflow side pipe 23 toward the pump chamber 16 is prevented. Instead of the check valves 25 and 26, the inflow side pipe 21 and the outflow side pipe 23 are provided with electromagnetically operated or pneumatically operated on-off valves, which open and close in accordance with the expansion and contraction of the tubeflam 15. Actuation of the valve may be controlled.

The pump drive unit 12 has a medium containing case 28 . A bellows 31 as a second flexible member is attached to the medium housing case 28. The bellows 31 comprises a bellows portion 31a, an end plate portion 31b provided at one end thereof, and an annular base end portion provided at the other end. 31c, and is integrally formed of a resin material such as fluororesin. The bellows portion 31a is elastically deformable in the axial direction.

A bellows 31 partitions an outer medium storage chamber 32 and an inner air chamber 33 . The bellows 31 as a whole is an axially stretchable flexible partition member. The medium storage chamber 32 communicates with the pump storage chamber 17 through a communication hole 34 formed in the pump case 14 and the medium storage case 28 . The pump storage chamber 17 and the medium storage chamber 32 are filled with a liquid medium M made of liquid, and the liquid medium M moves between the pump storage chamber 17 and the medium storage chamber 32 through the communication hole 34 . can be done. It should be noted that these can be separated without attaching the pump 11 to the pump drive unit 12 . In that case, a medium pipe for guiding the liquid medium M is connected between the pump 11 and the medium housing case 28 .

A cylinder 36 having an end plate 35 is attached to the medium housing case 28 , and the base end 31 c of the bellows 31 is sandwiched between the end plate 35 and the medium housing case 28 . A drive mechanism 27 having a rod 44 and an electric motor 46 is attached to the cylinder 36 , and the rod 44 is reciprocated by the drive mechanism 27 . A connecting plate 37 is attached to the open end of the cylinder 36 , and a supporting plate 39 to which the bearing 38 is attached is attached to the connecting plate 37 via a side plate 41 . A rod 44 is arranged so as to be reciprocatable in the axial direction through a through hole 42 formed in the end plate 35 and a through hole 43 formed in the connecting plate 37 . is screwed to the end plate portion 31b of the bellows 31. As shown in FIG.

An electric motor 46 is attached to the support plate 39 via a pedestal 47 to reciprocate the rod 44 in the axial direction. A base end portion of the feed screw shaft 51 is rotatably supported by the bearing 38 , and a tip end portion of the feed screw shaft 51 protrudes into an accommodation hole 52 formed in the rod 44 . The inner diameter of the accommodation hole 52 is larger than the outer diameter of the feed screw shaft 51 . The feed screw shaft 51 is a ball screw, and a nut 53 is screwed to the feed screw shaft 51 via balls. Nut 53 is attached to holder 54 , and holder 54 is fixed to the proximal end of rod 44 . A guide rod 55 axially penetrates the holder 54 , one end of the guide rod 55 is fixed to the connecting plate 37 and the other end is fixed to the support plate 39 . The holder 54 is guided by the guide rod 55 and moves axially without rotating. Although only one guide rod 55 is shown in FIGS. 1 and 2 , a plurality of guide rods 55 are provided in the drive mechanism 27 .

When the electric motor 46 as a driving member is driven, the rod 44 is axially moved via the nut 53 and the holder 54 by the feed screw shaft 51 . This causes the bellows 31 to expand and contract in the axial direction. FIG. 1 shows a state in which the tube frame 15 is radially expanded. Under this state, when the feed screw shaft 51 is rotated in one direction by the electric motor 46, the rod 44 moves in the direction of extending the bellows 31. and the bellows 31 expands. When the bellows 31 expands, the end plate portion 31b reduces the volume of the medium storage chamber 32 and the liquid medium M in the medium storage chamber 32 flows toward the pump storage chamber 17, as shown in FIG. When the liquid medium M flows into the pump housing chamber 17, the tube diaphragm 15 contracts in the radial direction, and the liquid L that has already been sucked into the pump chamber 16 from the liquid tank 22 is discharged toward the liquid discharge portion 24 outside. be. At this time, the check valve 25 prevents the liquid in the pump chamber 16 from flowing back to the inlet pipe 21 .

On the other hand, as shown in FIG. 2, when the feed screw shaft 51 is rotated in the opposite direction by the electric motor 46 with the tube frame 15 contracted in the radial direction, the rod 44 causes the bellows 31 to move. The bellows 31 is contracted by moving in the direction of contraction in the axial direction. When the bellows 31 contracts, the volume of the medium storage chamber 32 increases, and the liquid medium M in the pump storage chamber 17 flows toward the medium storage chamber 32, as shown in FIG. When the liquid medium M in the pump storage chamber 17 flows toward the medium storage chamber 32 , the tube flamm 15 expands in the radial direction, and the liquid L is sucked into the pump chamber 16 from the liquid tank 22 . At this time, the check valve 26 prevents the liquid in the outflow pipe 23 from flowing back toward the pump chamber 16 .

In this way, the rod 44 is driven by the electric motor 46 as a driving member to move the liquid medium M from the medium storage chamber 32 to the pump storage chamber 17 in the discharge direction and from the pump storage chamber 17 to the medium storage chamber 32 . is reciprocated in the inhalation direction and back. When the tubeflam 15 is radially expanded, the liquid L in the liquid tank 22 is sucked into the pump chamber 16, and when the tubephragm 15 is radially contracted, the liquid L in the pump chamber 16 is discharged to the outside. .

When the liquid L is drawn into the pump chamber 16 from the liquid tank 22 by axially contracting the bellows 31 and radially expanding the tubeflam 15 via the liquid medium M, the outer surface of the bellows 31a of the bellows 31 has a lower pressure than the inner surface. Therefore, when contracting the bellows 31 in the axial direction, there is a possibility that the bellows 31 is slightly deformed in the radial direction such that the average effective diameter of the bellows portion 31a increases. If the average effective diameter of the bellows portion 31a increases, a predetermined amount of liquid cannot be injected into the pump chamber 16, and the accuracy of discharging liquid from the pump chamber 16 may deteriorate. Furthermore, if the pressure on the outer surface of the bellows portion 31a is lower than that on the inner surface, the gas in the air chamber 33 may permeate the bellows 31 made of resin material and be mixed with the liquid medium M. If outside air is mixed in the liquid medium M, the accuracy of discharging the liquid from the pump chamber 16 is lowered.

On the other hand, when the liquid L is discharged from the pump chamber 16 into the outflow pipe 23 by extending the bellows 31 in the axial direction and contracting the tubeflam 15 via the liquid medium M, the bellows portion 31a of the bellows 31 The pressure of the liquid medium M is applied to the outer surface. Therefore, when the bellows 31 is stretched in the axial direction, it may be slightly deformed in the radial direction so that the average effective diameter of the bellows portion 31a becomes smaller. If the average effective diameter of the bellows portion 31a is reduced, there is a risk that the liquid discharge accuracy from the pump chamber 16 will be reduced. Even if the pressure on the outer surface of the bellows portion 31 a becomes higher than that on the inner surface, the liquid medium M made of liquid will not leak into the air chamber 33 through the bellows 31 .

A pressure regulating piston 56 is arranged in the cylinder 36 , the pressure regulating piston 56 is attached to the rod 44 and reciprocates in synchronization with the bellows 31 . A pressure regulating chamber 57 partitioned by the end plate 35 and the pressure regulating piston 56 is formed inside the cylinder 36 . A communication hole 58 is formed in the end plate 35 of the cylinder 36 , and the air chamber 33 communicates with the pressure regulation chamber 57 through the communication hole 58 . The outer diameter of the pressure regulating piston 56 is set larger than the average effective diameter of the bellows portion 31 a of the bellows 31 . The pressure regulating piston 56 constitutes a pressure regulating mechanism 60. When the bellows 31 is axially contracted by the rod 44 and the tube flamm 15 is radially expanded through the liquid medium M, the pressure regulating piston 56 is Since the diameter is larger than the average effective diameter of the bellows portion 31 a, the air in the air chamber 33 is sucked into the pressure adjustment chamber 57 .

As a result, the pressure in the air chamber 33 decreases as the rod 44 moves. As a result, the pressure difference between the air chamber 33 and the medium storage chamber 32 is reduced, so that the possibility that the air in the air chamber 33 permeates the bellows 31 and enters the medium storage chamber 32 can be suppressed. Pump characteristics can be maintained with high accuracy over a long period of time. Furthermore, when the bellows 31 is contracted, the deformation of the bellows portion 31a in the direction in which the average effective diameter increases in the radial direction is suppressed, and the amount of the liquid L to be injected into the pump chamber 16 can be set with high accuracy. .

The pressure regulating mechanism 60 having the pressure regulating piston 56 has a pressure regulating chamber having a larger diameter than the air chamber 33 when the bellows 31 is extended by the rod 44 and the tube fram 15 is radially contracted via the liquid medium M. The air in 57 is supplied to the air chamber 33, and the pressure in the air chamber 33 is increased as the rod 44 moves.

As a result, when the bellows 31 is extended, deformation of the bellows portion 31a in the direction of decreasing the average effective diameter is suppressed, and the discharge amount of the liquid L discharged from the pump chamber 16 to the outside can be set with high accuracy. can.

By changing the rotating direction of the electric motor 46 between forward and reverse directions, the tubeflam 15 can perform a pumping operation. The rotation direction and rotation speed of the electric motor 46 are controlled by a drive signal from a control section (not shown). In the control unit, data on the number of rotations in both the forward and reverse directions are stored in advance in a memory corresponding to the expansion and contraction stroke of the bellows 31 .

FIG. 3 is an enlarged sectional view showing the pressure regulating piston 56 shown in FIGS. 1 and 2. As shown in FIG. The pressure regulating piston 56 is provided with a negative pressure relief valve 61 and a positive pressure relief valve 62 .

The negative pressure relief valve 61 includes a cylindrical body 64a having an outside air introduction hole 63a, a valve seat 65a provided in the cylindrical body 64a, and a valve shaft 68a provided with a valve member 66a and supported by a valve shaft guide 67a. and a fixed sleeve 69a is mounted between the valve seat 65a and the valve stem guide 67a. A spring member 70a is mounted between the valve member 66a and the valve shaft guide 67a to apply a spring force to the valve member 66a in a direction to close the outside air introduction hole 63a. When the pressure in the pressure regulating chamber 57 becomes lower than the allowable negative pressure determined by the spring constant of the spring member 70a, that is, when the negative pressure value becomes large, the valve member 66a moves away from the valve seat 65a to introduce outside air. Hole 63a is opened. The pressure adjustment chamber 57 is communicated with the outside of the drive mechanism 27 and external air is supplied to the pressure adjustment chamber 57 . As a result, when the bellows 31 is contracted in the axial direction to expand the tubeflam 15 in the radial direction, the differential pressure between the air chamber 33 and the medium containing chamber 32 deforms the bellows portion 31 a of the bellows 31 . Excessive size is suppressed.

The positive pressure relief valve 62 includes a cylindrical body 64b formed with an air discharge hole 63b, a valve seat 65b provided in the cylindrical body 64b, and a valve shaft 68b provided with a valve member 66b and supported by a valve shaft guide 67b. and a fixed sleeve 69b is mounted between the valve seat 65b and the valve stem guide 67b. A spring member 70b that applies a spring force to the valve member 66b in a direction to close the air discharge hole 63b is mounted between the valve member 66b and the valve stem guide 67b. When the pressure in the pressure regulating chamber 57 becomes higher than the allowable positive pressure determined by the spring constant of the spring member 70b, the valve member 66b moves away from the valve seat 65b and the air in the pressure regulating chamber 57 is pumped through the air discharge hole 63b. It is discharged outside the drive unit 12 . As a result, when the bellows 31 is expanded in the axial direction and the tubeflam 15 is contracted in the radial direction, the pressure difference between the pressure in the air chamber 33 and the pressure in the medium storage chamber 32 deforms the bellows portion 31a of the bellows 31. It is suppressed that the magnitude of the positive pressure differential pressure becomes excessive.

As described above, the negative pressure relief valve 61 and the positive pressure relief valve 62 have valve shafts 68a and 68b facing in opposite directions to each other, but have common constituent members. If the rod 44 and the pressure regulating piston 56 can be moved synchronously, the rod 44 and the pressure regulating piston 56 may be moved by separate electric motors. If the differential pressure between the air chamber 33 and the medium storage chamber 32 does not become excessive enough to deform the bellows portion 31a of the bellows 31 when the bellows 31 is expanded and contracted in the axial direction, the pressure regulation is performed. The piston 56 may not be provided with the negative pressure relief valve 61 and the positive pressure relief valve 62 .

FIG. 4 is a cross-sectional view showing a liquid supply device 10b according to another embodiment. In FIG. 4, the same reference numerals are given to members that are common to the members constituting the liquid supply device 10a described above. and redundant explanations are omitted.

1 and 2, the pump 11 has a pump case 14 in which a housing hole 13 is formed, and is a radially elastically deformable tube formed of a resin material such as fluororesin. A fram 15 is positioned within the pump case 14 as a first flexible member. An inflow joint 18 is provided at one end of the pump case 14 and an outflow joint 19 is provided at the other end of the pump case 14 . In FIG. 4, the inflow pipe 21 connected to the inflow joint 18, the outflow pipe 23 connected to the outflow joint 19, and the like are omitted.

The pump drive unit 12 has a medium housing case 28 attached to the pump 11, and a bellows 31 is mounted inside the medium housing case 28 as a second flexible member. The bellows 31 has a bellows portion 31a, an end plate portion 31b provided at one end thereof, and an annular base end portion 31c provided at the other end. is molded into

A bellows 31 partitions an outer medium storage chamber 32 and an inner air chamber 33 . The medium storage chamber 32 communicates with the pump storage chamber 17 through a communication hole 34 formed in the pump case 14 and the medium storage case 28 . The pump storage chamber 17 and the medium storage chamber 32 are filled with a liquid medium M made of liquid.

The end plate 71 is fixed to the open end of the medium housing case 28 , and the base end 31 c of the bellows 31 is sandwiched between the end plate 71 and the medium housing case 28 . A rod 44 is inserted through a through hole 72 formed in an end plate 71 so as to reciprocate in the axial direction. A support plate 73 is connected to the end plate 71 by a connecting rod member 74 , and a feed screw shaft 51 is rotatably supported on the support plate 73 by a bearing 75 . A nut 53 screwed to the feed screw shaft 51 via a ball is fixed to the holder 54 , and the holder 54 is fixed to the rod 44 .

One end of the guide rod 55 is fixed to the end plate 71 , and the other end of the guide rod 55 is fixed to the support plate 73 . The guide rod 55 axially penetrates the holder 54 fixed to the rod 44, and the holder 54 is guided by the guide rod 55 and moved axially without rotation by the rotation of the feed screw shaft 51. .

An electric motor 46 for rotating the feed screw shaft 51 is attached to a base plate 76 attached to a support plate 73 , and includes a drive-side pulley 77 fixed to a main shaft 48 of the electric motor 46 and a rod 44 . A belt 79 is stretched between it and a pulley 78 on the driven side. The drive mechanism 27 with belt 79 is housed within a case 81 that is attached to the pump 11 .

A seal member 82 seals between the rod 44 and the through hole 72 of the end plate 71, and the air chamber 33 is a sealed space. When the inside of the medium containing chamber 32 becomes negative pressure, the negative pressure is supplied to the air chamber 33 by the pressure adjustment mechanism 60 corresponding to the pressure inside the medium containing chamber 32 . The pressure adjustment mechanism 60 is formed by an air pressure control mechanism 83, and FIG.

As shown in FIGS. 4 and 5, the pneumatic control mechanism 83 has a vacuum ejector 84 . The vacuum ejector 84 is known, and includes an air supply port 85, a diffuser 86 for ejecting compressed air supplied from the air supply port 85, and an exhaust port 87. The suction port 88 communicates with the diffuser 86 to create a vacuum. It is provided in the ejector 84 . When compressed air is supplied from the air supply port 85 toward the diffuser 86 , the suction port 88 is set to a negative pressure by the air passing through the diffuser 86 toward the exhaust port 87 . The suction port 88 communicates with a suction hole 89 formed in the end plate 71 through a channel 90 .

The pressure of the compressed air supplied to the air supply port 85 is regulated by the regulator 91 . The regulator 91 is of an external pilot operated type, and the pressure of the compressed air discharged from the input port 93 of the regulator 91 to the discharge port 94 is regulated by the pressure supplied to the pilot air port 92 . As shown in FIG. 5 , an air supply passage 96 is connected to a compressed air supply source 95 , and the air supply passage 96 is connected to an input port 93 . An on-off valve 97 is provided in the air supply passage 96 . The regulator 91 may be an internal pilot operated type in which the pressure is adjusted by operating a handle or the like instead of an external pilot operated type, a direct acting type, or an electro-pneumatic regulator in which the pressure is set by an electric signal.

In the liquid supply device 10b shown in FIG. 4 as well, the bellows 31 is contracted in the axial direction to radially expand the tubeflam 15 via the liquid medium M, thereby injecting the liquid L from the liquid tank 22 into the pump chamber 16. When doing so, the pressure in the medium storage chamber 32 becomes negative. At this time, the on-off valve 97 is turned on, and the compressed air supplied from the compressed air supply source 95 is discharged to the air supply port 85 of the vacuum ejector 84 . Therefore, a vacuum, that is, a negative pressure is generated in the suction port 88 , and the air chamber 33 communicating with the suction port 88 through the flow path 90 is set to a negative pressure corresponding to the pressure in the medium storage chamber 32 . In addition, the negative pressure generated by the vacuum ejector 84 by adjusting the pressure supplied from the regulator 91 is adjusted to a size that does not deform when the bellows 31 expands, and the rod 44 is removed while the on-off valve 97 is kept on. may be reciprocated to contract the bellows 31 .

As a result, the air in the air chamber 33 can be prevented from permeating the bellows 31 and entering the medium storage chamber 32, and the pump characteristics can be maintained with high accuracy over a long period of time. Furthermore, when the bellows 31 is contracted, the deformation of the bellows portion 31a in the direction in which the average effective diameter increases in the radial direction is suppressed, and the amount of the liquid L to be injected into the pump chamber 16 can be set with high accuracy. .

The on/off operation of the opening/closing valve 97 is controlled by a control signal from a control unit (not shown) so as to correspond to the forward rotation and reverse rotation of the electric motor 46 .

In the liquid supply apparatus shown in FIG. 4, a power transmission mechanism having a belt 79 is provided between the main shaft 48 of the electric motor 46 and the feed screw shaft 51. As with the apparatus, the electric motor 46 may be arranged such that the main shaft 48 is coaxial with the lead screw shaft 51 . Similarly, in the liquid supply device shown in FIGS. 1 and 2, the main shaft 48 of the electric motor 46 may be connected to the feed screw shaft 51 via a power transmission mechanism.

FIG. 6 is a sectional view showing a liquid supply device 10c of another embodiment. Like the liquid supply apparatuses 10a and 10b described above, this liquid supply apparatus 10c includes a pump 11 having a tube frame 15 as a first flexible member. The medium containing case 28 has a side wall 28b integrally provided with a top wall 28a, and an end plate 28c is attached to the open end of the medium containing case 28. As shown in FIG. The medium housing case 28 is provided with a diaphragm 29 as a second flexible member that partitions the inside into a medium housing chamber 32 and an air chamber 33 . are in communication.

The diaphragm 29 has an annular base portion 29a fixed between the side wall 28b and the end plate 28c, a central connecting portion 29b connected to the rod 44, and an elastic deformation portion 29c therebetween. Like the bellows 31 described above, it is integrally formed of a resin material such as fluororesin. The rod 44 is reciprocated in the axial direction by the drive mechanism 27 to provide a discharge direction for supplying the liquid medium M from the medium storage chamber 32 to the pump storage chamber 17 and an injection direction for returning the liquid medium M from the pump storage chamber 17 to the medium storage chamber 32 . It is free to reciprocate in both directions. The driving mechanism may be a mechanism that converts the rotary motion of the electric motor 46 into a linear reciprocating motion of the rod 44 as described above, or a mechanism such as a pneumatic cylinder that linearly reciprocates the rod 44 by fluid pressure. .

In this way, the rod 44 has a discharge direction for supplying the liquid medium M from the medium storage chamber 32 to the pump storage chamber 17 by the drive mechanism 27 and an injection direction for returning the liquid medium M from the pump storage chamber 17 to the medium storage chamber 32 . is moved to When the rod 44 is moved in the injection direction to inject the liquid L from the liquid tank 22 into the pump chamber 16, the pressure on the outer surface of the diaphragm 29 is lower than that on the inner surface. For this reason, similarly to the bellows 31 described above, the elastically deformable portion 29c may be excessively deformed in the axial direction, and the liquid discharge accuracy from the pump chamber 16 may be deteriorated. Furthermore, if the pressure on the outer surface of the elastic deformation portion 29c is lower than that on the inner surface, the gas in the air chamber 33 may permeate the diaphragm 29 made of resin material and mix with the liquid medium M having a large negative pressure. If outside air is mixed in the liquid medium M, there is a possibility that the accuracy of discharging the liquid from the pump chamber 16 is lowered.

A suction hole 89 communicating with the air chamber 33 is provided in order to reduce the pressure in the air chamber 33 when the rod 44 is moved in the injection direction and the volume of the air chamber 33 is reduced in order to prevent deterioration of liquid ejection accuracy. is connected to the pressure regulating mechanism 60 via a flow path 90 . As the pressure adjustment mechanism 60, the air pressure control mechanism 83 shown in FIG. 5 can be applied.

FIG. 7 is a cross-sectional view showing a liquid supply device 10d that is still another embodiment. A pump case 14a forming the pump 11 in the liquid supply device 10d has an inflow side joint 18 and an outflow side joint 19 provided at one end, and an end plate 14b at the other end. A bellows 31 having the same structure as the bellows 31 shown in FIG. 1 is provided as a flexible member in the pump case 14a. The bellows 31 as a flexible member has a bellows portion 31a, an end plate portion 31b provided at one end thereof, and an annular base end portion 31c provided at the other end thereof, and is made of a resin material such as fluorine resin. integrally molded. The bellows portion 31a is axially elastically deformable, and the bellows 31 as a whole is a flexible pump member that is axially stretchable. The pump chamber 16 and the air chamber 33 are separated by the bellows 31, and the pump chamber 16 and the air chamber 33 are provided in the pump case 14a.

A rod 44a is attached to the end plate portion 31b, and the rod 44a is axially reciprocated by the drive mechanism 27. As shown in FIG. The rod 44 a can reciprocate in a discharge direction for discharging the liquid in the pump chamber 16 to the outside and an injection direction for injecting the liquid into the pump chamber 16 .

In this manner, even in the liquid supply device 10d in which the bellows 31 as a flexible member incorporated in the pump case 14 is directly expanded and contracted by the rod 44a, the rod 44a is extended in the injection direction to extend the liquid from the liquid tank 22 to the pump chamber. When the liquid L is injected into 16, the outer surface of the bellows portion 31a of the bellows 31 has a lower pressure than the inner surface. Therefore, when the bellows 31 is contracted in the axial direction, there is a possibility that the bellows 31a is slightly deformed in the radial direction so that the average effective diameter of the bellows portion 31a becomes larger, and the liquid discharge accuracy from the pump chamber 16 may be lowered. There is Furthermore, if the pressure on the outer surface of the bellows portion 31a becomes lower than that on the inner surface, the gas in the air chamber 33 may permeate the bellows 31 made of resin material and mix with the liquid medium M having a large negative pressure. If outside air is mixed in the liquid medium M, there is a possibility that the accuracy of discharging the liquid from the pump chamber 16 is lowered.

Therefore, in order to prevent the deterioration of the liquid ejection accuracy, the rod 44a is moved in the injection direction to lower the pressure of the air chamber 33 when the volume of the air chamber 33 is reduced. A pressure adjusting mechanism 60 is connected to the hole 89 through a flow path 90 . As the pressure adjustment mechanism 60, the air pressure control mechanism 83 shown in FIG. 5 can be applied.

FIG. 8 shows a pneumatic circuit diagram forming an air pressure control mechanism 83 as an example of the pressure adjusting mechanism 60 in the liquid supply device shown in FIGS.

The pneumatic control mechanism 83 has a vacuum tank 102 connected to a vacuum pump 101 . A predetermined amount of negative pressure air is stored in the vacuum tank 102, and functions as a buffer tank when pressure fluctuates. A vacuum channel 103 connected to the vacuum tank 102 is provided with an on-off valve 97 and a regulator 104. A channel 90 connected to the output port of the regulator 104 is connected to the suction holes 89 of the liquid supply devices 10c and 10d. It is connected. Therefore, when the volume of the air chamber 33 is reduced and the pressure of the air chamber 33 is reduced, the on-off valve 97 opens the vacuum flow path 103 to supply negative pressure air to the air chamber 33 .

The air pressure control mechanism 83 of this form can also be applied as the air pressure control mechanism 83 of the liquid supply device 10b shown in FIG.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the liquid supply devices 10a and 10b in which the reciprocating motion of the rod 44 increases or decreases the volume of the pump chamber 16 via the liquid medium M, the tubeflam 15 is used as the first flexible member. Alternatively, the bellows 31 shown in FIG. 7 or the diaphragm 29 shown in FIG. 6 may be applied. Also, as the second flexible member, instead of the bellows 31, the diaphragm 29 shown in FIG. 6 may be applied.

10a to 10d liquid supply device 11 pump 12 pump drive unit 14 pump case 15 tube flam (first flexible member)
16 pump chamber 17 pump housing chamber 27 drive mechanism 28 medium housing case 31 bellows (second flexible member)
32 Medium storage chamber 33 Air chamber 36 Cylinder 44 Rod 46 Electric motor 51 Feed screw shaft 54 Holder 55 Guide rod 56 Pressure adjustment piston 57 Pressure adjustment chamber 60 Pressure adjustment mechanism 61 Negative pressure relief valve 62 Positive pressure relief valve 71 End plate 72 Penetration Hole 73 Support plate 74 Connecting rod 83 Air pressure control mechanism 84 Vacuum ejector 85 Air supply port 86 Diffuser 87 Exhaust port 88 Suction port 91 Regulator 92 Pilot air port 93 Input port 94 Discharge port 95 Compressed air supply source 96 Air supply passage 97 On-off valve 101 Vacuum pump

Claims (13)

A first flexible member is disposed within the pump case and partitions the pump chamber and the pump housing chamber, the volume of the pump chamber is increased to inject liquid into the pump chamber, and the volume of the pump chamber is decreased. a liquid supply device that discharges the liquid in the pump chamber to the outside,
a medium housing case comprising a second flexible member separating a medium housing chamber communicating with the pump housing chamber and an air chamber;
a liquid medium filled in the pump housing chamber and the medium housing chamber;
The rod attached to the second flexible member is arranged in a discharge direction for supplying the liquid medium from the medium storage chamber to the pump storage chamber and an injection direction for returning the liquid medium from the pump storage chamber to the medium storage chamber. a drive member that reciprocates with and
a pressure adjustment mechanism that drives the rod in the injection direction to reduce the pressure of the air chamber when the volume of the air chamber is reduced;
A liquid supply device having The liquid supply device according to claim 1,
The pressure adjustment mechanism is
a cylinder having a pressure regulating chamber communicating with the air chamber; and a pressure regulating piston accommodated in the cylinder so as to reciprocate in the axial direction,
The pressure regulating piston is
When the rod is driven in the injection direction to reduce the volume of the air chamber, the air in the air chamber is sucked into the pressure adjustment chamber, and the rod is driven in the discharge direction to increase the volume of the air chamber. A liquid supply device that supplies the air in the pressure regulation chamber into the air chamber when the liquid supply device is to be used. The liquid supply device according to claim 2,
The pressure regulating piston is provided with a positive pressure relief valve for discharging the air in the pressure regulating chamber to the outside when the pressure in the pressure regulating chamber becomes higher than the allowable positive pressure,
A liquid supply device, wherein the pressure regulating piston is provided with a negative pressure relief valve for supplying air into the pressure regulating chamber when the pressure in the pressure regulating chamber becomes lower than an allowable negative pressure. The liquid supply device according to claim 2 or 3,
The liquid supply device according to claim 1, wherein the pressure regulating piston is provided on the rod, and the rod reciprocates the second flexible member and the pressure regulating piston synchronously. The liquid supply device according to claim 1,
The pressure adjustment mechanism is
A vacuum ejector comprising an air supply port communicating with an air supply source, a diffuser for ejecting compressed air supplied from the air supply port, and a suction port communicating with the diffuser and with the air chamber. , liquid feeder. The liquid supply device according to claim 5,
When an on-off valve is provided in an air supply passage between the air supply port and the compressed air supply source, and the rod is moved in the injection direction to return the liquid medium from the pump storage chamber to the medium storage chamber. , the liquid supply device, wherein the on-off valve opens the air supply passage. The liquid supply device according to claim 5,
an on-off valve provided in an air supply passage between the air supply port and a compressed air supply source; and an on-off valve provided between the on-off valve and the air supply port to adjust the pressure of the compressed air supplied to the air supply port. A liquid supply device having a regulator for adjustment, wherein the on-off valve reciprocates the rod while the air supply passage is open. The liquid supply device according to claim 1,
The liquid supply device, wherein the pressure adjustment mechanism is a vacuum pump having a vacuum channel that communicates with the air chamber. The liquid supply device according to claim 8,
An on-off valve is provided in the vacuum flow path, and the on-off valve opens the vacuum flow path when the rod is moved in the injection direction to return the liquid medium from the pump storage chamber to the medium storage chamber. Device. In the liquid supply device according to any one of claims 1 to 9,
The first flexible member includes a tube frame which is elastically deformable in the radial direction and has the pump chamber provided inside and the pump housing chamber provided outside; A bellows provided with the pump chamber on the outside and the pump housing chamber on the outside, or a diaphragm that is elastically deformable in the axial direction and has the pump chamber formed on the outside and the pump housing chamber formed on the inside. , liquid feeder. In the liquid supply device according to any one of claims 1 to 10,
The second flexible member is a bellows which is elastically deformable in the axial direction and has the air chamber inside and the medium storage chamber outside, or a bellows which is elastically deformable in the axial direction and is outside. a diaphragm having the medium storage chamber formed therein and the air chamber formed therein. A flexible member is provided in the pump case and partitions the pump chamber and the air chamber, the volume of the pump chamber is increased to inject liquid into the pump chamber, and the volume of the pump chamber is decreased to decrease the volume of the pump. A liquid supply device for discharging a liquid in a room to the outside,
a driving member that reciprocates a rod attached to the flexible member in a discharge direction for discharging the liquid in the pump chamber to the outside and an injection direction for injecting the liquid into the pump chamber;
a pressure adjustment mechanism that reduces the pressure of the air chamber when the rod is moved in the injection direction and the volume of the air chamber is reduced;
A liquid supply device having 13. The liquid supply device of claim 12, wherein
The flexible member is a bellows which is elastically deformable in the axial direction and has the pump chamber outside and the air chamber inside, or a bellows which is elastically deformable in the axial direction and has the pump chamber outside. is formed and the air chamber is formed inside the diaphragm.

Images