Fluid Dispensing System

Abstract

To provide a fluid discharge system which can supply a fluid to a discharge device stably while inhibiting increase of an installation space and costs.SOLUTION: A fluid discharge system 10 includes: a discharge device 30 which discharges a fluid; a pump 20 which may supply the fluid stored in a storage part 22 to the discharge device 30; a supply passage 40 which connects the discharge device 30 with the pump 20 so that the fluid can pass therebetween; a buffer tank 50 which is disposed in the middle of the supply passage 40 and may suction and discharge the fluid; and a residual quantity grasp part 90 which grasps the residual quantity of the fluid in the discharge device 30. In the fluid discharge system 10, operation of the buffer tank 50 is controlled based on the residual quantity of the fluid grasped by the residual quantity grasp part 90.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluid dispensing system for supplying a fluid to a dispensing device and dispensing the fluid. [Background technology]

[0002] Conventionally, there has been provided a pump device capable of pumping up and pumping a fluid prepared in a container such as a pail can, such as the pump device disclosed in Patent Document 1 below. Conventionally, there has also been provided a fluid discharge system formed by connecting such a pump device to a discharge device such as a dispenser via piping. The fluid discharge system supplies the fluid pumped by the pump device to the discharge device, thereby enabling the discharge device to discharge the fluid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-203465 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned fluid discharge system can continue to discharge the fluid from the discharge device as long as the prepared fluid remains in the container of the pump device. However, when the prepared fluid on the pump device side runs out, the supply of the fluid to the discharge device stops. Therefore, the above-mentioned fluid discharge system needs to temporarily stop the discharge of the fluid from the discharge device and replenish the pump device with the fluid every time the fluid runs out of the container of the pump device.

[0005] Therefore, the inventors have considered preparing a plurality of pump devices (e.g., two pump devices) for one discharge device in a fluid discharge system, and making it possible to switch between pump devices capable of supplying fluid to the discharge device as needed. As a result, the inventors have found that a fluid discharge system having such a configuration can switch the connection destination of the discharge device to a pump device that is ready for fluid when the fluid runs out in the pump device connected to the discharge device, and can minimize the interruption of discharge of fluid. However, the inventors have found that such a configuration requires a large installation space and increases costs by providing a plurality of pump devices (e.g., two pump devices) for one discharge device.

[0006] Therefore, an object of the present invention is to provide a fluid discharge system that can stably supply a fluid to a discharge device while suppressing increases in installation space and costs. [Means for solving the problem]

[0007] (1) The fluid discharge system of the present invention comprises a discharge device which discharges a fluid, a pump having a storage section and capable of supplying the fluid to the discharge device by pressurizing the fluid stored in the storage section, a supply path connecting the pump and the discharge device so that the fluid can pass between them, a buffer tank which is positioned midway through the supply path and capable of sucking in and discharging the fluid, and a remaining amount grasping section which grasps the remaining amount of fluid in the discharge device, and the operation of the buffer tank is controlled based on the remaining amount of fluid grasped by the remaining amount grasping section.

[0008] The fluid discharge system of the present invention includes a pump capable of supplying fluid to the discharge device, and a buffer tank capable of sucking and discharging fluid. Therefore, the fluid discharge system of the present invention can suck and store fluid in the buffer tank, and discharge and supply the fluid from the buffer tank at an appropriate timing. Therefore, the fluid discharge system of the present invention can stably supply fluid to the discharge device by operating the pump and the buffer tank in a complementary manner.

[0009] In addition, the fluid discharge system of the present invention can control the operation of the buffer tank based on the remaining amount of fluid in the discharge device grasped by the remaining amount grasping unit. Therefore, the fluid discharge system of the present invention can control the suction operation and discharge operation of the fluid in the buffer tank to be appropriately performed according to the remaining amount of fluid in the discharge device. Therefore, the fluid discharge system of the present invention can minimize the risk of a shortage or excess of the remaining amount of fluid in the discharge device.

[0010] The fluid discharge system of the present invention can stably supply the fluid to the discharge device by the above-mentioned operation without providing multiple pumps. Therefore, the fluid discharge system of the present invention can suppress the increase in installation space and cost compared to a configuration provided with multiple pumps.

[0011] (2) In the fluid discharge system of the present invention, it is preferable that the remaining amount grasping unit has a pressure detection device provided between the buffer tank and the discharge device in the supply path or in the discharge device, and grasps the remaining amount of fluid in the discharge device based on the measurement value of the pressure detection device.

[0012] According to this configuration, the remaining amount of fluid in the discharge device can be appropriately grasped based on the pressure detected by the pressure detection device. Therefore, according to the fluid discharge system of the present invention, the pump and the buffer tank are operated appropriately according to the remaining amount of fluid in the discharge device, and the fluid can be appropriately and stably supplied to the discharge device so that the discharge device does not have a shortage or excess of the remaining amount of fluid.

[0013] (3) In the fluid discharge system of the present invention, when the supply of fluid by the pump is restricted, the buffer tank may discharge fluid, thereby enabling the supply of fluid to the discharge device to continue.

[0014] The fluid discharge system of the present invention can compensate for the reduction in supply capacity due to the restriction of the fluid supply by the pump by discharging the fluid through the buffer tank. Therefore, even in a case where the supply of fluid by the pump has to be restricted due to a lack of fluid remaining in the pump, the fluid discharge system of the present invention can stably supply the fluid to the discharge device appropriately so that the discharge device does not run out of fluid.

[0015] (4) When supplying fluid to the discharge device, the fluid discharge system of the present invention may preferably perform either one or both of the following: the buffer tank discharges the fluid when the remaining amount of fluid in the discharge device as determined by the remaining amount determining unit falls below a predetermined lower limit; and the buffer tank stops discharging the fluid when the remaining amount of fluid in the discharge device as determined by the remaining amount determining unit exceeds a predetermined upper limit.

[0016] The fluid discharge system of the present invention can realize a stable supply of fluid to the discharge device by discharging the fluid from the buffer tank on the condition that the remaining amount of fluid in the discharge device falls below a predetermined lower limit when supplying the fluid to the discharge device. Specifically, even in a case where the supply of fluid by the pump has to be restricted due to a shortage of the remaining amount of fluid in the pump, the fluid discharge system of the present invention can supply the fluid from the buffer tank to the discharge device when the remaining amount of fluid in the discharge device falls below a predetermined lower limit, thereby suppressing the occurrence of a shortage of the remaining amount of fluid in the discharge device.

[0017] In addition, the fluid discharge system of the present invention can prevent an excessive supply of fluid to the discharge device by stopping the discharge of fluid from the buffer tank when the remaining amount of fluid in the discharge device exceeds a predetermined upper limit, thereby preventing problems such as unstable supply pressure, discharge pressure, and discharge amount of fluid in the discharge device.

[0018] (5) In the fluid discharge system of the present invention, the buffer tank can accumulate the fluid inside the buffer tank by sucking in the fluid, and the discharge device can continue to discharge the fluid while the fluid is accumulating.

[0019] The fluid discharge system of the present invention can continue to discharge the fluid by the discharge device even during accumulation of the fluid in the buffer tank. Therefore, the fluid discharge system of the present invention can minimize a decrease in productivity caused by, for example, stopping the discharge of the fluid from the discharge device due to accumulation of the fluid in the buffer tank.

[0020] (6) The fluid discharge system of the present invention may preferably be configured to, when accumulating fluid in the buffer tank, either or both of the following: the buffer tank sucks in the fluid when the remaining amount of fluid in the discharge device as determined by the remaining amount determining unit exceeds a predetermined upper limit; and the buffer tank stops sucking in the fluid when the remaining amount of fluid in the discharge device as determined by the remaining amount determining unit falls below a predetermined lower limit.

[0021] The fluid discharge system of the present invention is configured such that the buffer tank sucks in the fluid on the condition that the remaining amount of the fluid in the discharge device exceeds a predetermined upper limit, thereby making effective use of the period during which it is not necessary to supply the fluid to the discharge device, and the fluid can be sucked in and accumulated in the buffer tank. In addition, by doing so, the fluid discharge system of the present invention can prevent an excessive supply of fluid to the discharge device when it is not necessary to supply the fluid to the discharge device. This can prevent problems such as unstable supply pressure, discharge pressure, and discharge amount of the fluid in the discharge device.

[0022] In addition, the fluid discharge system of the present invention is configured to stop the suction of the fluid by the buffer tank on the condition that the remaining amount of the fluid in the discharge device falls below a predetermined lower limit, so that when the remaining amount of the fluid in the discharge device is reduced, the fluid can be supplied to the discharge device preferentially over the buffer tank. This allows the fluid discharge system of the present invention to suppress the occurrence of discharge defects due to a lack of the remaining amount of the fluid. The remaining amount of the fluid in the discharge device can be determined by, for example, directly measuring and deriving the amount using a remaining amount sensor or the like provided in the discharge device, detecting the amount of the fluid flowing into and out of the discharge device and subtracting the amount of the fluid, or indirectly deriving the amount of the fluid by the time the fluid flows in and out of the discharge device.

[0023] (7) In the fluid discharge system of the present invention, the buffer tank is capable of accumulating the fluid inside the buffer tank by sucking in the fluid, and when the supply of fluid by the pump is restricted, the buffer tank is capable of discharging the fluid accumulated inside, thereby enabling the supply of fluid to the discharge device to be continued, and it is preferable that the operation of the buffer tank, both for accumulating the fluid and for supplying the fluid, is controlled based on the remaining amount of fluid in the discharge device as determined by the remaining amount determining unit.

[0024] The fluid discharge system of the present invention is capable of continuously supplying the fluid to the discharge device by discharging the fluid accumulated inside the buffer tank when the supply of the fluid by the pump is limited. The operation of the buffer tank is controlled based on the remaining amount of fluid in the discharge device for both the accumulation of the fluid and the supply of the fluid. Therefore, the fluid discharge system of the present invention operates the pump and the buffer tank in a complementary manner, and can stably supply the fluid to the discharge device.

[0025] (8) In the fluid discharging system of the present invention, the buffer tank, when accumulating the fluid, performs at least one of the following operations: sucking in the fluid on condition that the remaining amount of fluid in the discharging device grasped by the remaining amount grasping unit exceeds a predetermined first upper limit value, and stopping the suction of the fluid on condition that the remaining amount of fluid in the discharging device grasped by the remaining amount grasping unit falls below a predetermined first lower limit value; and, when supplying the fluid, it performs at least one of the following operations: discharging the fluid on condition that the remaining amount of fluid in the discharging device grasped by the remaining amount grasping unit falls below a predetermined second lower limit value, and stopping the discharge of the fluid on condition that the remaining amount of fluid in the discharging device grasped by the remaining amount grasping unit exceeds a predetermined second upper limit value.

[0026] The fluid discharge system of the present invention controls the accumulation of fluid in the buffer tank based on a first upper limit value and a first lower limit value for the remaining amount of fluid in the discharge device. Specifically, the fluid discharge system of the present invention can accumulate fluid in the buffer tank when the remaining amount of fluid in the discharge device exceeds the first upper limit value, and can stop the accumulation of fluid in the buffer tank when the remaining amount of fluid in the discharge device falls below the first lower limit value. Therefore, the fluid discharge system of the present invention can accumulate fluid in the buffer tank at an appropriate timing depending on the remaining amount of fluid in the discharge device.

[0027] The fluid discharge system of the present invention controls the discharge of the fluid from the buffer tank based on the second upper limit and second lower limit of the remaining amount of the fluid in the discharge device. Specifically, the fluid discharge system of the present invention can discharge the fluid and supply it to the discharge device when the remaining amount of the fluid in the discharge device falls below the second lower limit, and can stop the discharge of the fluid and stop the supply to the discharge device when the remaining amount exceeds the second upper limit. Therefore, the fluid discharge system of the present invention can discharge the fluid from the buffer tank at an appropriate timing depending on the remaining amount of the fluid in the discharge device.

[0028] In addition, the remaining amount of fluid in the discharge device can be determined by, for example, directly measuring it using a remaining amount sensor provided in the discharge device, detecting the amount of fluid flowing into and out of the discharge device and subtracting it to determine the amount of fluid directly or indirectly, or indirectly based on the time it takes for the fluid to flow in and out of the discharge device.

[0029] (9) The fluid discharge system of the present invention may be characterized in that the buffer tank is equipped with a position variable member whose position varies within a predetermined range of variation depending on the amount of fluid remaining, and a detection device that detects the position of the position variable member, and the remaining amount of fluid in the buffer tank can be determined based on the correlation between the capacity of the buffer tank and the position of the position variable member.

[0030] According to this configuration, the remaining amount of fluid in the buffer tank can be continuously detected. Also, according to the above-mentioned configuration, the upper and lower limits of the amount of fluid stored in the buffer tank can be appropriately set or changed to control the operation of the fluid discharge system. Effect of the Invention

[0031] According to the present invention, it is possible to provide a fluid discharge system that can stably supply a fluid to a discharge device while suppressing increases in installation space and costs. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a schematic diagram showing an example of a fluid discharge system of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of a discharge device used in the fluid discharge system of FIG. [Diagram 3] FIG. 2(a) is a cross-sectional view showing the configuration of a buffer tank used in the fluid discharge system of FIG. 1 in a pressurized state, and FIG. 2(b) is an enlarged cross-sectional view of a main part of FIG. [Figure 4] 2 is a cross-sectional view showing the configuration of a buffer tank used in the fluid discharge system of FIG. 1 in a reduced pressure state. FIG. [Diagram 5] 2 is a cross-sectional view showing the configuration of a buffer tank used in the fluid discharge system of FIG. 1 in a retaining state. [Figure 6] 2A and 2B are explanatory diagrams illustrating the operating states of the various parts of the fluid discharge system of FIG. 1 when the supply pressure is high and when the supply pressure is low in the pump supply mode, respectively. [Figure 7] 4 is a timing chart when the fluid delivery system of FIG. 1 operates in a pump supply mode. [Figure 8] 2 is a flow chart of the fluid delivery system of FIG. 1 operating in a pump supply mode. [Figure 9]2A and 2B are explanatory diagrams illustrating the operating states of the various parts of the fluid discharge system of FIG. 1 when the supply pressure is high and when the supply pressure is low in the tank accumulation mode, respectively. [Figure 10] 4 is a timing chart when the fluid discharge system of FIG. 1 operates in a tank accumulation mode. [Figure 11] 2 is a flow chart of the fluid dispensing system of FIG. 1 operating in a tank accumulation mode. [Figure 12] 2A and 2B are explanatory diagrams illustrating the operating states of the various parts of the fluid discharge system of FIG. 1 when the supply pressure is high and when the supply pressure is low in the tank supply mode, respectively. [Figure 13] 4 is a timing chart when the fluid dispensing system of FIG. 1 operates in a tank supply mode. [Figure 14] 2 is a flow chart of the fluid dispensing system of FIG. 1 operating in a tank supply mode. [Figure 15] 2A and 2B are explanatory diagrams illustrating the operating states of the various parts of the fluid discharge system of FIG. 1 when the supply pressure is high and when the supply pressure is low in the combined supply mode, respectively. [Figure 16] 2 is a timing diagram of the fluid dispensing system of FIG. 1 operating in a multiple delivery mode. [Figure 17] 2 is a flow chart of the fluid dispensing system of FIG. 1 operating in a multiple delivery mode. [Figure 18] 2 is a flow chart of the fluid dispensing system of FIG. 1 operating in a first mode of operation. [Figure 19] 2 is a timing chart when the fluid dispensing system of FIG. 1 operates in a first operation mode. [Figure 20] 2 is a flow chart of the fluid dispensing system of FIG. 1 operating in a second mode of operation. [Figure 21] 1. FIG. 4 is a cross-sectional view of a modified example of the buffer tank used in the fluid discharge system of FIG. [Figure 22]1. FIG. 4 is a cross-sectional view of a main part of a modified example of a buffer tank used in the fluid discharge system of FIG. [Diagram 23] 1. FIG. 4 is a cross-sectional view of a main part of a modified example of a buffer tank used in the fluid discharge system of FIG. [Figure 24] FIG. 13 is an explanatory diagram showing an example in which a detection device capable of continuously detecting the amount of fluid stored in a buffer tank is provided. [Diagram 25] 13A and 13B are image diagrams of an example of a user interface showing the amount of fluid stored in the buffer tank and the operating mode of the fluid dispensing system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, a fluid discharge system 10 according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the configuration of the fluid discharge system 10 will be described first, and then the operation of the fluid discharge system 10 will be described.

[0034] <Configuration of the fluid discharge system 10> As shown in Fig. 1, the fluid discharge system 10 is configured by connecting a pump 20 and a discharge device 30 with a supply path 40. The fluid discharge system 10 is configured by providing a buffer tank 50 in the middle of the supply path 40. The fluid discharge system 10 also includes a remaining amount grasping unit 90 for grasping the remaining amount of fluid in the discharge device 30. The fluid discharge system 10 also includes a control device 200 for controlling the operation of the pump 20, the discharge device 30, and the buffer tank 50. The fluid discharge system 10 can discharge the fluid supplied by the pump 20 and the buffer tank 50 toward a workpiece in the discharge device 30.

[0035] The pump 20 is a device for pumping up and pressure-feeding a fluid from a storage section 22 in which the fluid is stored. The pump 20 is connected to a supply path 40 via a pipe. Therefore, the fluid pumped up from the storage section by the pump 20 can be pressure-feed to the discharge device 30 side via the supply path 40.

[0036] The discharge device 30 is configured by a rotary volumetric pump. In this embodiment, the discharge device 30 is configured by a so-called uniaxial eccentric screw pump. As shown in FIG. 2, the discharge device 30 is configured to accommodate a rotor 102, a stator 104, a power transmission mechanism 106, and the like inside a casing 100. The casing 100 is a metallic cylindrical member, and is provided with a first opening 110 at one end in the longitudinal direction. In addition, a second opening 112 is provided on the outer periphery of the casing 100. The second opening 112 communicates with the internal space of the casing 100 at a middle portion 114 located in the longitudinal middle portion of the casing 100.

[0037] The first opening 110 and the second opening 112 are portions that function as a suction port and a discharge port, respectively, of a single-shaft eccentric screw pump that constitutes the discharge device 30. In the discharge device 30, the first opening 110 can function as a discharge port and the second opening 112 can function as a suction port by rotating the rotor 102 in the forward direction. Also, the first opening 110 can function as a suction port and the second opening 112 can function as a discharge port by rotating the rotor 102 in the reverse direction.

[0038] Stator 104 is a member having a substantially cylindrical external shape formed of an elastic body such as rubber, or resin, etc. An inner peripheral wall 116 of stator 104 has an n-thread single-stage or multi-stage female thread shape. In this embodiment, stator 104 has a two-thread multi-stage female thread shape. Furthermore, through-hole 118 of stator 104 is formed so that its cross-sectional shape (opening shape) is substantially elliptical when viewed in cross section at any position in the longitudinal direction of stator 104.

[0039] The rotor 102 is a metallic shaft body, and has a single-stage or multi-stage male screw shape with n-1 threads. In this embodiment, the rotor 102 has a single-stage eccentric male screw shape. The rotor 102 is formed so that the cross-sectional shape is a substantially perfect circle when viewed in cross section at any position in the longitudinal direction. The rotor 102 is inserted into a through hole 118 formed in the above-mentioned stator 104, and is freely eccentrically rotatable inside the through hole 118.

[0040] When the rotor 102 is inserted into the stator 104, the outer peripheral wall 120 of the rotor 102 and the inner peripheral wall 116 of the stator 104 come into close contact with each other at their tangent lines, and a fluid transport path 122 (cavity) is formed between the inner peripheral wall 116 of the stator 104 and the outer peripheral wall 120 of the rotor 102. The fluid transport path 122 extends in a spiral shape in the longitudinal direction of the stator 104 and the rotor 102.

[0041] When the rotor 102 is rotated in the through hole 118 of the stator 104, the fluid transport path 122 advances in the longitudinal direction of the stator 104 while rotating in the stator 104. Therefore, when the rotor 102 is rotated, the fluid is sucked from one end side of the stator 104 into the fluid transport path 122, and the fluid is transported toward the other end side of the stator 104 while being confined in the fluid transport path 122, and can be discharged at the other end side of the stator 104. Specifically, when the rotor 102 is rotated forward, an operation of sucking in a fluid from the second opening 112 and discharging it from the first opening 110 (discharge operation) can be performed. Also, when the rotor 102 is rotated in the reverse direction, an operation of sucking in a fluid in the opposite direction to the discharge operation, that is, from the first opening 110 side toward the second opening 112 side (pull-back operation) can be performed.

[0042] The power transmission mechanism 106 is for transmitting power from the driving machine 124 to the rotor 102 described above. The power transmission mechanism 106 has a power transmission unit 126 and an eccentric rotation unit 128. The power transmission unit 126 is provided at one end side in the longitudinal direction of the casing 100. The eccentric rotation unit 128 is provided at the intermediate portion 114. The eccentric rotation unit 128 is a portion that connects the power transmission unit 126 and the rotor 102 so as to be capable of transmitting power. The eccentric rotation unit 128 includes a connecting shaft 130 that is formed of a conventionally known coupling rod, a screw rod, or the like. Therefore, the eccentric rotation unit 128 can transmit the rotational power generated by operating the driving machine 124 to the rotor 102 and rotate the rotor 102 eccentrically.

[0043] The supply path 40 is a flow path that connects the pump 20 and the discharge device 30 so that the fluid can pass between them. A buffer tank 50, which will be described in detail later, is provided in the middle of the supply path 40. Specifically, the supply path 40 has a primary supply path 42 that connects between the primary side of the buffer tank 50 (the upstream side in the flow direction of the fluid in the supply path 40) and the pump 20, and a secondary supply path 44 that connects between the secondary side of the buffer tank 50 (the downstream side in the flow direction of the fluid in the supply path 40) and the discharge device 30.

[0044] A sensor 92 constituting a remaining amount grasping unit 90, which will be described later, and a valve 48 are provided in the middle of the supply path 40. The sensor 92 can be, for example, a pressure gauge or a flow meter, which is capable of detecting the state of the fluid in the supply path 40. In this embodiment, the sensor 92 is a pressure gauge. The sensor 92 is disposed in the supply path 40, between the discharge device 30 and the buffer tank 50. The valve 48 is disposed in the supply path 40, between the pump 20 and the buffer tank 50. The valve 48 is capable of restricting (blocking in this embodiment) the flow of the fluid from the pump 20 to the discharge device 30. The valve 48 may be configured as a so-called two-way valve, a check valve, or the like.

[0045] The buffer tank 50 is disposed midway through the above-mentioned supply path 40. The buffer tank 50 is capable of sucking and discharging the fluid. The buffer tank 50 can accumulate the fluid inside by sucking the fluid. When the pump 20 stops supplying the fluid, the buffer tank 50 discharges the fluid accumulated inside, thereby enabling the supply of the fluid to the discharge device 30 to be continued. The operation of the buffer tank 50 is controlled by the control device 200 according to the remaining amount of the fluid in the discharge device 30. As shown in FIGS. 3 to 5, the buffer tank 50 has a tank portion 52 and a volume variation mechanism 54.

[0046] The tank section 52 is capable of causing a fluid to flow in and out of the supply path 40. In this embodiment, the tank section 52 is provided with a connection section 56 on one end side of a tubular (substantially cylindrical in this embodiment) tank main body section 52a extending in a predetermined axial direction, and is provided with a communicating space 58 and a non-communicating space 60 inside the tank main body section 52a.

[0047] The connection part 56 is provided on one axial end side of the tank body part 52a constituting the tank part 52. The connection part 56 is a part that is connected to the supply path 40. The connection part 56 has a flow path 56a that extends in a direction (in the present embodiment, a radial direction) that intersects with the axial direction of the tank part 52. The connection part 56 has connection ports 56b, 56c at both ends of the flow path 56a. The connection ports 56b, 56c open at the periphery of the tank part 52 and are capable of connecting piping that constitutes the supply path 40. The connection part 56 also has a communication hole 56d at a radial intermediate part of the tank part 52. The tank part 52 is in communication with the flow path 56a and the internal space (communication space 58) of the tank body part 52a via the communication hole 56d.

[0048] The communication space 58 is a space provided on the side of the tank part 52 where the connection part 56 is provided. The communication space 58 is formed to communicate with the supply path 40 via the above-mentioned connection part 56. Therefore, the tank part 52 is capable of sucking and discharging fluid into and from the communication space 58 between the tank part 52 and the supply path 40 connected to the connection part 56.

[0049] The non-communicating space 60 is a space that is not connected to the supply path 40. The non-communicating space 60 is a space adjacent to the communicating space 58 in the axial direction of the tank portion 52 on the opposite side to the connecting portion 56 with respect to the communicating space 58. The non-communicating space 60 is separated from the communicating space 58 by a piston portion 62 (partition portion) of the volume fluctuation mechanism 54, which will be described in detail later. The volume fluctuation mechanism 54 is connected to an end portion of the non-communicating space 60. As a result, the non-communicating space 60 is connected to a casing 68 that constitutes a drive portion 64 of the volume fluctuation mechanism 54.

[0050] The volume variation mechanism 54 is an operating mechanism that varies the volume of the communicating space 58 in the tank portion 52. The volume variation mechanism 54 has a piston portion 62 and a driving portion 64, and can move the piston portion 62 in the axial direction of the tank portion 52 inside the tank portion 52 by the driving portion 64. Therefore, the volume variation mechanism 54 can change the volume (volume ratio) of the communicating space 58 and the non-communicating space 60 inside the tank portion 52 by changing the position of the piston portion 62 by the driving portion 64.

[0051] The piston portion 62 separates the inside of the tank portion 52 into a communicating space 58 and a non-communicating space 60. In this embodiment, the piston portion 62 is a piston. The outer diameter of the piston constituting the piston portion 62 is approximately the same as the inner diameter of the tank portion 52. A seal member 62a is attached to the outer periphery of the piston portion 62. As a result, the piston portion 62 separates the internal space of the tank main body portion 52a into the communicating space 58 and the non-communicating space 60 while sealing to prevent leakage of liquids including fluids and gases.

[0052] The driving unit 64 is for moving the piston portion 62 in the axial direction inside the tank main body portion 52a. The driving unit 64 has a rod portion 66, a casing 68, a partition wall 70, and an air supply and exhaust device 72. The rod portion 66 is inserted into the tank main body portion 52a from the non-communicating space 60 side. The rod portion 66 is arranged so as to extend in the axial direction of the tank main body portion 52a. The piston portion 62 is connected to one end side of the rod portion 66. The connection portion between the rod portion 66 and the piston portion 62 may be integrated by screwing, for example, by providing a female thread on one side and a male thread on the other side, or by using a fixing tool such as a screw to integrate the two. Also, instead of fixing and integrating the piston portion 62 and the rod portion 66 as in this embodiment, the piston portion 62 and the tip portion of the rod portion 66 may be connected by contacting each other. Also, the tip portion 66a of the rod portion 66 may be detachable from the shaft portion 66b of the rod portion 66. If a plurality of tip portions 66a having different lengths are prepared, the length of the rod portion 66 can be changed on the tip portion 66a side, thereby adjusting the stroke length of the piston portion 62.

[0053] Further, a partition wall 70 is connected to the other end side of the rod portion 66. The partition wall 70 is integrated with the rod portion 66. In this embodiment, the other end side of the rod portion 66 is axially shaped, but the length may be adjustable similarly to the tip portion 66a.

[0054] The casing 68 is a cylindrical member having a hollow internal space. One end of the casing 68 is closed. The other end of the casing 68 is connected to the non-communicating space 60 of the tank main body 52a and is not connected to the external space. The casing 68 has a first casing connection port 68a and a second casing connection port 68b at one end and the other end in the axial direction.

[0055] The partition wall 70 separates the internal space of the casing 68 into a first space 70a on the first casing connection port 68a side and a second space 70b on the second casing connection port 68b side. The partition wall 70 is plate-shaped and disposed so that its outer peripheral surface is in close contact with the inner peripheral surface of the casing 68 via a seal member such as an O-ring. The partition wall 70 is connected to the other end side (opposite to the connection end of the piston portion 62) of the rod portion 66 on the surface on the second space 70b side. The partition wall 70, together with the rod portion 66, is capable of reciprocating in the axial direction of the casing 68 while maintaining a position in which its outer peripheral surface is in contact with the inner peripheral surface of the casing 68. The partition wall 70 can be reciprocated in the axial direction inside the casing 68 by introducing and discharging gas through the first casing connection port 68a and the second casing connection port 68b and changing the pressure balance between the first space 70a and the second space 70b.

[0056] An intake and exhaust device 72 is connected to the first casing connection port 68a by piping. The intake and exhaust device 72 can introduce and exhaust gas (air in this embodiment) to and from the casing 68, and can also stop the introduction and exhaust of gas between the casing 68. The intake and exhaust device 72 includes a solenoid valve 72b, a pilot check valve 72c, and a first speed controller 72d arranged in this order from the gas supply source 72a toward the casing 68 in the middle of a first piping system 74 connecting a gas supply source 72a and the first casing connection port 68a of the casing 68.

[0057] The supply source 72a is capable of pressure-feeding gas toward the casing 68. The supply source 72a can be configured by, for example, a pump or a compressor. The solenoid valve 72b switches the passage of the gas supplied by the supply source 72a in the first piping system 74. The solenoid valve 72b may be of an appropriate switching type, such as a three-position closed center type or a three-position pressure center type, but in this embodiment, a solenoid valve adopting a three-position exhaust center switching type is used. If a solenoid valve of the three-position exhaust center type is used as the solenoid valve 72b as in this embodiment, sufficient responsiveness can be ensured even if the solenoid valve 72b and the casing 68 are distant from each other.

[0058] The supply source 72a is connected to the intake port PI of the solenoid valve 72b. The two output ports A and B of the solenoid valve 72b are connected to the pilot check valve 72c by piping. The solenoid valve 72b is also provided with two exhaust ports EA and EB that are open to the atmosphere. The solenoid valve 72b can be switched between three states, a first state, a second state, and a third state, by changing the valve position. Specifically, as shown in FIG. 3, the first state is a state in which the intake port PI and the output port B are connected, and the exhaust port EA and the output port A are connected. As shown in FIG. 4, the second state is a state in which the intake port PI and the output port A are connected, and the exhaust port EB and the output port B are connected. As shown in FIG. 5, the third state is a state in which the output ports A and B are connected to the exhaust ports EA and EB, respectively.

[0059] The pilot check valve 72c has three connection ports PA, PB, and PC. The connection ports PA and PB of the pilot check valve 72c are connected by piping to the output ports A and B provided on the solenoid valve 72b, respectively. In addition, the pilot check valve 72c has a pipe connected to the first casing connection port 68a connected to the connection port PC. When no pressure is applied to the connection port PA, the pilot check valve 72c functions as a check valve that allows gas to flow from the connection port PB to the connection port PC and blocks the reverse flow from the connection port PC to the connection port PB. When a pressure of a predetermined value or more is applied to the connection port PA, the pilot check valve 72c is released from its function as a check valve and allows gas to flow from the connection port PC to the connection port PB.

[0060] The pilot check valve 72c is connected to the solenoid valve 72b via the first piping system 74 as described above. Therefore, when the solenoid valve 72b is in the first state, and pressure is not applied to the connection port PA of the pilot check valve 72c, but pressure is applied to the connection port PB, gas flows from the connection port PB to the connection port PC, and gas can be introduced into the casing 68 from the first casing connection port 68a. When the solenoid valve 72b is in the second state, pressure of a predetermined value or more is applied to the connection port PA, and the pilot check valve 72c does not function as a check valve. The connection port PA is opened to the atmosphere via the exhaust port EB of the solenoid valve 72b. Therefore, when the solenoid valve 72b is in the second state, gas can be discharged from the first casing connection port 68a of the casing 68. When the solenoid valve 72b is in the third state, pressure is not applied to either the connection port PA or PB, and the pilot check valve 72c functions as a check valve. Therefore, when the solenoid valve 72b is in the third state, the casing 68 can be put into a state in which gas does not flow in or out.

[0061] The first speed controller 72d is provided in the middle of a pipe line connecting the above-mentioned pilot check valve 72c and the first casing connection port 68a of the casing 68. The first speed controller 72d is equipped with a residual pressure exhaust valve. In addition, the first speed controller 72d is capable of meter-out control.

[0062] On the other hand, a second piping system 80 is connected to the second casing connection port 68b of the casing 68. A silencer 82 and a second speed controller 84 are provided in the second piping system 80. The second piping system 80 is open to the atmosphere via the silencer 82. As a result, the second piping system 80 is configured to allow gas (air in this embodiment) to flow in and out in the area on the second casing connection port 68b side of the casing 68. In addition, the second speed controller 84 is capable of meter-out control.

[0063] By utilizing the above-mentioned configuration, the buffer tank 50 can realize three states: a pressurized state, a depressurized state, and a holding state. Each of these states can be realized by controlling the movement of the piston portion 62 inside the tank portion 52 by the drive portion 64 constituting the volume variation mechanism 54.

[0064] Specifically, the pressurized state is a state in which a pressurizing force is applied to the fluid. The pressurized state can be realized by reducing the volume of the communication space 58 communicating with the supply path 40 in the tank portion 52 by the volume fluctuation mechanism 54. To explain in more detail, when the buffer tank 50 is put into the pressurized state, as shown in FIG. 3, the solenoid valve 72b constituting the drive portion 64 is put into the first state, and gas is supplied to the solenoid valve 72b by the supply source 72a. As a result, the state is created in which no pressure acts on the connection port PA of the pilot check valve 72c, but pressure acts on the connection port PB, and gas flows from the connection port PB to the connection port PC, and gas is introduced into the first space 70a from the first casing connection port 68a provided in the casing 68 of the drive portion 64. Accordingly, the partition wall 70 moves in a direction in which the first space 70a expands inside the casing 68. As a result, the pressure acting on the non-communicating space 60 side of the piston portion 62 connected to the partition wall 70 via the rod portion 66 is increased. Accordingly, the piston portion 62 moves in a direction that reduces the volume of the communication space 58. In this manner, the buffer tank 50 is brought into a pressurized state in which a pressurizing force is applied to the fluid.

[0065] The reduced pressure state is a state in which a decompression force is exerted on the fluid. The reduced pressure state can be realized by increasing the volume of the communication space 58 in the tank section 52 that communicates with the supply path 40 by the volume fluctuation mechanism 54. To explain in more detail, when the buffer tank 50 is put into the reduced pressure state, as shown in FIG. 4, the solenoid valve 72b constituting the drive section 64 is put into the second state and gas is supplied to the solenoid valve 72b by the supply source 72a. As a result, a pressure of a predetermined value or more acts on the connection port PA of the pilot check valve 72c, and the pilot check valve 72c does not function as a check valve. In addition, the connection port PA is opened to the atmosphere via the exhaust port EB of the solenoid valve 72b. Therefore, when the solenoid valve 72b is put into the second state, gas is discharged from the first casing connection port 68a of the casing 68. Accordingly, inside the casing 68, the partition wall 70 moves in a direction in which the second space 70b increases. Accordingly, the pressure acting on the non-communicating space 60 side of the piston portion 62 connected to the partition wall 70 via the rod portion 66 decreases. This causes the piston portion 62 to move in a direction that increases the volume of the communicating space 58. In this way, the buffer tank 50 is brought into a decompressed state in which a decompressing force acts on the fluid.

[0066] The holding state is a state in which neither pressurizing nor depressurizing force is applied to the fluid. The holding state can be realized by stopping the increase or decrease in the volume of the communication space 58 by the volume change mechanism 54. More specifically, when the buffer tank 50 is put into the holding state, as shown in FIG. 5, the solenoid valve 72b constituting the drive unit 64 is put into the third state. As a result, no pressure acts on either of the connection ports PA and PB provided in the pilot check valve 72c, and the pilot check valve 72c functions as a check valve. Therefore, when the solenoid valve 72b is put into the third state, it is possible to put the casing 68 into a state in which no gas flows in or out. Therefore, inside the casing 68, the partition wall 70 is put into a stopped state. Accordingly, the state is such that no pressure fluctuations acting on the piston portion 62 connected to the partition wall 70 via the rod portion 66 or no volume fluctuations occur in the communication space 58. In this way, the buffer tank 50 is put into a holding state in which neither pressurizing nor depressurizing force is applied to the fluid.

[0067] As shown in FIG. 1, a remaining amount grasping unit 90 is provided downstream of the above-mentioned buffer tank 50 in the flow direction of the fluid toward the discharge device 30. The remaining amount grasping unit 90 is for grasping the remaining amount of the fluid in the discharge device 30. The remaining amount grasping unit 90 may grasp the remaining amount of the fluid in the discharge device 30 by directly measuring, for example, or indirectly grasping the remaining amount of the fluid in the discharge device 30 from the supply state of the fluid to the discharge device 30 or the discharge state of the fluid in the discharge device 30. Specifically, the remaining amount grasping unit 90 may grasp the remaining amount of the fluid in the discharge device 30 indirectly from a measurement value related to the supply state of the fluid, such as the supply pressure of the fluid to the discharge device 30 or the flow rate of the fluid to the discharge device 30.

[0068] Further, the remaining amount grasping unit 90 is preferably provided integrally with, for example, a sensor 92 for measuring the supply pressure or flow rate of the fluid, and a processing unit 94 for performing processing to grasp the remaining amount of the fluid in the discharge device 30 based on the measurement values obtained by the sensor 92, or the sensor 92 and the processing unit 94 may be provided separately. In the present embodiment, a pressure sensor for detecting the supply pressure of the fluid to the discharge device 30 (hereinafter also referred to as "supply pressure P") is employed as the sensor 92. Further, the function of the processing unit 94 is assigned to a control device 200 described later. Therefore, by inputting the measurement value of the sensor 92 to the control device 200, the control device 200 can grasp the remaining amount of the fluid in the discharge device 30. In the present embodiment, on the condition that the supply pressure P detected by the sensor 92 is within the range of the upper limit value (hereinafter also referred to as "upper limit pressure PH") and the lower limit value (hereinafter also referred to as "lower limit pressure PL") of a predetermined pressure range (PL < P < PH), the control device 200 grasps that the remaining amount of the fluid in the discharge device 30 is within an appropriate range.

[0069] The control device 200 is for controlling the operation of the fluid discharge system 10. In addition to the function as the processing unit 94 of the remaining amount grasping unit 90 described above, the control device 200 controls the operations of the pump 20, the discharge device 30, the buffer tank 50, and the like.

[0070] ≪Regarding the operation of the fluid discharge system 10≫ The fluid discharge system 10 can be operated in four operation modes under the control of the control device 200. Specifically, the fluid discharge system 10 can be operated in four operation modes: (1) pump supply mode, (2) tank accumulation mode, (3) tank supply mode, and (4) composite supply mode. Further, the fluid discharge system 10 can stably discharge the fluid in the discharge device 30 by sequentially performing the operations in the four operation modes. Hereinafter, regarding the operation of the fluid discharge system 10, first, the operations in the four operation modes will be described. Further, after the description of the operations in each operation mode, the operation of the fluid discharge system 10 realized by sequentially performing the operations in each operation mode will be described.

[0071] (1) Pump supply mode The pump supply mode is an operation mode in which the fluid is supplied from the pump 20 to the discharge device 30 while the buffer tank 50 is in a holding state. As shown in Fig. 6, in the pump supply mode, the control device 200 opens the valve 48 provided in the supply path 40 between the buffer tank 50 and the pump 20. The control device 200 also controls the operation of the pump 20 to operate or stop depending on the remaining amount of the fluid in the discharge device 30 grasped by the remaining amount grasping unit 90.

[0072] In this embodiment, the control device 200 grasps the remaining amount of fluid in the discharge device 30 using the supply pressure P to the discharge device 30 detected by the sensor 92 as an index, and controls the operation of the pump 20 according to the supply pressure P. Specifically, as shown in the timing chart of FIG. 7, the control device 200 stops the operation of the pump 20 on the condition that the supply pressure P is equal to or higher than a predetermined upper limit pressure PH, since it is not necessary to supply fluid to the discharge device 30. On the other hand, on the condition that the supply pressure P is equal to or lower than a predetermined lower limit pressure PL, the control device 200 operates the pump 20 on the condition that the remaining amount of fluid in the discharge device 30 is below an appropriate value. The operation of the fluid discharge system 10 in the pump supply mode is as shown in the flowchart of FIG. 8. Hereinafter, the operation of the fluid discharge system 10 in the pump supply mode will be described in more detail with reference to the flowchart of FIG. 8.

[0073] (Step 1-1) In step 1-1, the control device 200 opens the valve 48. If the valve 48 is already open, the control device 200 maintains the valve 48 in the open state. After that, the control device 200 advances the control flow to step 1-2.

[0074] (Step 1-2) In step 1-2, the control device 200 checks whether the remaining amount of fluid in the storage section 22 of the pump 20 has decreased to the lower limit of the storage section 22. If the remaining amount of fluid in the storage section 22 is at the lower limit, the control flow ends because the fluid cannot be pumped even if the pump 20 is operated. On the other hand, if there is fluid in the storage section 22 that exceeds the lower limit, the control device 200 advances the control flow to step 1-3.

[0075] (Step 1-3) In step 1-3, the control device 200 checks whether the supply pressure P detected by the sensor 92 constituting the remaining amount grasping unit 90 is equal to or lower than the lower limit pressure PL. Here, when the supply pressure P is higher than the lower limit pressure PL, there is no need to operate the pump 20 to supply the fluid to the discharge device 30. Therefore, when the supply pressure P is higher than the lower limit pressure PL, the control device 200 waits in step 1-3. On the other hand, when the supply pressure P is equal to or lower than the lower limit pressure PL, it is necessary to supply the fluid to the discharge device 30. Therefore, in this case, the control device 200 advances the control flow to step 1-4.

[0076] (Step 1-4) In step 1-4, the control device 200 operates the pump 20. As a result, the fluid stored in the storage section 22 is pumped by the pump 20 toward the discharge device 30. Thereafter, the control device 200 advances the control flow to step 1-5.

[0077] (Step 1-5) In step 1-5, the control device 200 checks whether the remaining amount of fluid in the storage section 22 of the pump 20 has reached a lower limit. If the remaining amount of fluid in the storage section 22 has reached the lower limit, the control device 200 advances the control flow to step 1-6. On the other hand, if the remaining amount of fluid has not reached the lower limit, the control device 200 advances the control flow to step 1-7.

[0078] (Step 1-6) In the above-mentioned step 1-5, if the remaining amount of the fluid in the storage section 22 has reached the lower limit, further operation of the pump 20 will not allow the fluid to be supplied to the discharge device 30. Therefore, in step 1-6, the control device 200 ends the series of control flows.

[0079] (Step 1-7) In step 1-7, the control device 200 checks whether the supply pressure P is equal to or greater than the upper limit pressure PH. If the supply pressure P has not reached the upper limit pressure PH, the control device 200 returns the control flow to step 1-5 to continue supplying the fluid to the discharge device 30. On the other hand, if the supply pressure P is equal to or greater than the upper limit pressure PH, the control device 200 advances the control flow to step 1-8.

[0080] (Step 1-8) In step 1-8, the control device 200 stops the pump 20. This stops the supply of fluid from the pump 20 to the discharge device 30. Thereafter, the control device 200 advances the control flow to step 1-9.

[0081] (Step 1-9) In step 1-9, the control device 200 checks the remaining amount of fluid in the storage section 22 of the pump 20. If the remaining amount of fluid has not reached the lower limit of the storage section 22, the control device 200 returns the control flow to step 1-3. On the other hand, if the remaining amount of fluid has reached the lower limit of the storage section 22, the pump 20 cannot supply any more fluid to the discharge device 30, and therefore the control flow is terminated.

[0082] (2) Tank accumulation mode Next, the tank accumulation mode will be described in detail. The tank accumulation mode is an operation mode in which the fluid is accumulated (charged) in the buffer tank 50 in preparation for the tank supply mode, which will be described later in detail, while continuing to supply the fluid from the pump 20. The tank accumulation mode is an operation mode in which the fluid is accumulated inside the buffer tank 50 (communication space 58) by sucking the fluid into the buffer tank 50. In the tank accumulation mode, the operation of the buffer tank 50 during accumulation is controlled based on the measurement value of the remaining amount grasping unit 90. The tank accumulation mode is also an operation mode in which the discharge device 30 can continue to discharge the fluid even during accumulation of the fluid in the buffer tank.

[0083] 9, when operating in the tank accumulation mode, the control device 200 opens the valve 48 provided in the supply path 40 to enable the fluid to be supplied from the pump 20 to the buffer tank 50. The control device 200 also controls the operation of the pump 20 to operate or stop depending on the remaining amount of the fluid in the discharge device 30 grasped by the remaining amount grasping unit 90.

[0084] In the tank accumulation mode, the control device 200 controls the operation of the pump 20 and the buffer tank 50 based on the measurement value of the remaining amount grasping unit 90, as shown in the operation explanatory diagram of FIG. 9 and the timing chart of FIG. 10. The control device 200 grasps the remaining amount of the fluid in the discharge device 30 using the supply pressure P to the discharge device 30 as an index, and controls the operation of the pump 20 and the buffer tank 50 according to the supply pressure P. Specifically, when the supply pressure P is higher than a predetermined upper limit pressure PH (first upper limit value), a sufficient amount of the fluid is stored in the discharge device 30, so the buffer tank 50 is depressurized and the fluid is accumulated in the communication space 58 of the tank section 52. More specifically, as shown in FIG. 9(a), the control device 200 opens the valve 48 to stop the pump 20 and depressurizes the buffer tank 50. As a result, the fluid is accumulated in the buffer tank 50. The operating conditions, such as the timing and period for which the buffer tank 50 is put into a reduced pressure state, may be determined taking into account undershoot of the supply pressure P, for example, by limiting it to a predetermined time after the supply pressure P reaches the upper limit pressure PH.

[0085] On the other hand, when the supply pressure P is lower than the predetermined lower limit pressure PL (first lower limit value), the remaining amount of fluid in the discharge device 30 is below an appropriate value, so the buffer tank 50 is put into a holding state and accumulation of the fluid in the communication space 58 is stopped. More specifically, as shown in FIG. 9(b), the control device 200 operates the pump 20 with the valve 48 in an open state, and puts the buffer tank 50 into a holding state. In this way, the control device 200 supplies the fluid pumped by the pump 20 to the discharge device 30.

[0086] By performing such control in the tank accumulation mode, the control device 200 accumulates the fluid in the buffer tank 50, aiming for a state in which the supply pressure P is sufficiently high (when there is a margin of fluid remaining in the discharge device 30). That is, in the fluid discharge system 10, the control device 200 controls the operation in the tank accumulation mode by utilizing the advantage that the buffer tank 50 can realize a holding state. The operation of the fluid discharge system 10 in the tank accumulation mode is as shown in the flowchart of FIG. 11. The operation of the fluid discharge system 10 in the tank accumulation mode will be described in more detail below with reference to the flowchart of FIG. 11.

[0087] (Step 2-1) In step 2-1, the control device 200 opens the valve 48. If the valve 48 is already open, the valve 48 is maintained in the open state. This allows the pump 20 to pump fluid to the buffer tank 50 and the discharge device 30. After that, the control device 200 advances the control flow to step 2-2.

[0088] (Step 2-2) In step 2-2, the control device 200 checks whether the remaining amount of fluid in the storage unit 22 of the pump 20 has decreased to the lower limit of the storage unit 22. If the remaining amount of fluid in the storage unit 22 is at the lower limit, the control flow in Fig. 11 is terminated. On the other hand, if the amount of fluid in the storage unit 22 exceeds the lower limit, the control device 200 advances the control flow to step 2-3.

[0089] (Step 2-3) In step 2-3, the control device 200 checks whether the supply pressure P detected by the sensor 92 constituting the remaining amount grasping unit 90 is equal to or lower than the lower limit pressure PL. Here, when the supply pressure P is higher than the lower limit pressure PL, there is no need to operate the pump 20 to supply the fluid to the discharge device 30, and therefore the pump is placed in a standby state in step 2-3. On the other hand, when the supply pressure P is equal to or lower than the lower limit pressure PL, it is necessary to supply the fluid to the discharge device 30. In this case, the control device 200 advances the control flow to step 2-4.

[0090] (Step 2-4) In step 2-4, the control device 200 operates the pump 20. As a result, the fluid stored in the storage section 22 is pumped by the pump 20 toward the discharge device 30. Thereafter, the control device 200 advances the control flow to step 2-5.

[0091] (Step 2-5) In step 2-5, the control device 200 checks whether the remaining amount of the fluid in the storage section 22 of the pump 20 has reached a lower limit. If the remaining amount of the fluid in the storage section 22 has reached the lower limit, the control device 200 advances the control flow to step 2-6. On the other hand, if the remaining amount of the fluid has not reached the lower limit, the control device 200 advances the control flow to step 2-7.

[0092] (Step 2-6) When the control flow has moved to step 2-6, the remaining amount of fluid in the reservoir 22 is insufficient. Therefore, the control device 200 stops the pump 20. Then, the control flow ends.

[0093] (Step 2-7) In step 2-7, the control device 200 checks whether the supply pressure P is equal to or lower than the upper limit pressure PH. If the supply pressure P is lower than the upper limit pressure PH, the control flow returns to step 2-5 and the operation of the pump 20 continues. On the other hand, if the supply pressure P is equal to or higher than the upper limit pressure PH, the control device 200 advances the control flow to step 2-8.

[0094] (Step 2-8) In step 2-8, the controller 200 stops the pump 20. Thereafter, the controller 200 advances the control flow to step 2-9.

[0095] (Step 2-9) In step 2-9, the control device 200 puts the buffer tank 50 into a depressurized state. Specifically, the control device 200 controls the operation of the solenoid valve 72b constituting the volume fluctuation mechanism 54 of the buffer tank 50 so that it is in the second state. In addition, gas is supplied to the solenoid valve 72b by the supply source 72a consisting of an air compressor or the like. This causes the pilot check valve 72c to lose its function as a check valve, and gas is discharged from the first casing connection port 68a in the casing 68 of the volume fluctuation mechanism 54 through the connection port PA of the pilot check valve 72c and the exhaust port EB of the solenoid valve 72b. As a result, the partition wall 70 starts to move inside the casing 68, and the piston part 62 moves in a direction in which the volume of the communication space 58 increases. In this way, the buffer tank 50 is put into a depressurized state in which a depressurizing force acts on the fluid. When the communication space 58 of the buffer tank 50 is put into a depressurized state, the fluid starts to flow from the supply path 40 into the communication space 58 and accumulates therein. When the buffer tank 50 is put into a depressurized state in step 2-9, the control device 200 advances the control flow to step 2-10.

[0096] (Step 2-10) In step 2-10, the control device 200 manages the amount of accumulated fluid so that the amount of accumulated fluid is within a predetermined range after the start of accumulation of the fluid in the buffer tank 50 in step 2-9. The amount of accumulated fluid in the buffer tank 50 can be directly or indirectly derived and grasped by, for example, a method of directly measuring and deriving the amount of accumulated fluid using a residual amount sensor or a method of detecting and subtracting the amount of fluid flowing into and out of the buffer tank 50, or indirectly grasped by the time of flowing fluid into and out of the buffer tank 50. In this embodiment, the control device 200 manages the amount of accumulated fluid after the start of accumulation of the fluid in the buffer tank 50 in step 2-9 based on the time elapsed since the buffer tank 50 was put into a depressurized state in step 2-9. In step 2-10, the control device 200 checks whether the elapsed time Tx after the start of accumulation of the fluid in the buffer tank 50 in step 2-9 is equal to or greater than a predetermined time T2. The elapsed time T can be measured, for example, by a timer provided in the control device 200. Here, when it is confirmed that the elapsed time T is equal to or greater than the predetermined time T2, the control device 200 advances the control flow to step 2-11.

[0097] (Step 2-11) In step 2-11, the control device 200 switches the buffer tank 50 to a holding state, and puts the fluid into a state in which neither pressurizing nor depressurizing force is applied. Specifically, the control device 200 puts the solenoid valve 72b provided in the drive unit 64 of the buffer tank 50 into a third state. As a result, no pressure acts on either of the connection ports PA and PB provided in the pilot check valve 72c, and the pilot check valve 72c functions as a check valve, and the inflow and outflow of gas in the casing 68 of the drive unit 64 is stopped. As a result, the partition wall 70 arranged inside the casing 68 stops, and the piston unit 62 connected to the partition wall 70 stops in the tank unit 52. In this way, the control device 200 puts the buffer tank 50 into a holding state. After that, the control device 200 advances the control flow to step 2-12.

[0098] (Step 2-12) In step 2-12, the control device 200 checks whether the amount of fluid stored in the buffer tank 50 has reached its upper limit. The amount of fluid stored in the buffer tank 50 may be determined based on the output value from a remaining amount sensor provided in the buffer tank 50 or a position sensor capable of detecting the position of the partition wall 70, or the amount of fluid flowing into and out of the buffer tank 50 may be detected or derived, and the amount of fluid flowing into and out of the buffer tank 50 may be determined based on the amount of fluid flowing into and out of the buffer tank 50. In step 2-12, if it is determined that the amount of fluid stored in the buffer tank 50 has not reached its upper limit, the control device 200 returns the control flow to step 2-2 to further accumulate the fluid. On the other hand, if it is determined that the amount of fluid stored in the buffer tank 50 has reached its upper limit, the control device 200 completes a series of control flows.

[0099] (3) Tank supply mode Next, the tank supply mode will be described in detail. The tank supply mode is an operation mode in which the fluid is supplied from the buffer tank 50 to the discharge device 30 while the pump 20 is stopped. The operation in the tank supply mode is an operation mode for discharging the fluid from the buffer tank 50 to the supply path 40 when the pump 20 is stopped for replacing the storage section 22 in the pump 20 or refilling the storage section 22 with the fluid, thereby enabling the supply of the fluid to the discharge device 30 to be continued.

[0100] In the tank supply mode, as shown in the operation explanatory diagram of FIG. 12 and the timing chart of FIG. 13, the operation of the pump 20 and the buffer tank 50 is controlled based on the measurement value of the remaining amount grasping unit 90. Specifically, in the tank supply mode, when supplying the fluid to the discharge device 30, the operation control is performed so that the buffer tank 50 discharges the fluid on the condition that the measurement value of the remaining amount grasping unit 90 falls below a predetermined lower limit value (second lower limit value). More specifically, on the condition that the supply pressure P detected by the sensor 92 falls below a predetermined lower limit pressure PL, the pump 20 is stopped and the buffer tank 50 is pressurized with the valve 48 closed. As a result, the fluid is supplied from the buffer tank 50 to the discharge device 30 in a state in which the pump 20 does not pump the fluid. The lower limit pressure PL, which is the second lower limit value, is set to the same value (pressure) as the first lower limit value in the tank accumulation mode described above, but may be different values ​​(pressures).

[0101] On the other hand, in the tank supply mode, the operation of the buffer tank 50 is controlled so as to stop discharging the fluid on condition that the measurement value of the remaining amount grasping unit 90 exceeds a predetermined upper limit value (second upper limit value). More specifically, in the tank supply mode, on condition that the supply pressure P detected by the sensor 92 exceeds a predetermined upper limit pressure PH, the pump 20 is stopped and the buffer tank 50 is in a holding state with the valve 48 closed. This prevents the fluid from being excessively supplied to the discharge device 30 that is sufficiently filled with the fluid. The upper limit pressure PH, which is the second upper limit value, is set to the same value (pressure) as the first upper limit value in the tank accumulation mode described above, but they may be different values ​​(pressures).

[0102] In the tank supply mode, the above-mentioned operations are performed in accordance with the flowchart shown in Fig. 14. Hereinafter, the operation of the fluid dispensing system 10 in the tank supply mode will be described in further detail with reference to the flowchart in Fig. 14.

[0103] (Step 3-1) In step 3-1, the control device 200 checks the fluid storage state in the buffer tank 50. As a result, if the amount of fluid stored in the buffer tank 50 is the lower limit, there is a concern that the buffer tank 50 will not be able to supply the fluid, so the control device 200 completes a series of control flows. Here, in this step and the following steps, "when the amount of fluid stored in the buffer tank 50 is the lower limit" may be a state in which the amount of fluid stored has decreased to a level in which the fluid cannot be supplied, but in this embodiment, the control device 200 specifies a stage slightly before the level in which the fluid cannot be supplied (a state in which a small amount of fluid remains) as a case in which the amount of fluid stored is the lower limit, and performs operation control. On the other hand, when the amount of fluid stored in the buffer tank 50 is greater than the lower limit, the control device 200 advances the control flow to step 3-2.

[0104] (Step 3-2) In step 3-2, the control device 200 checks the remaining amount of fluid in the discharge device 30. Specifically, the control device 200 checks whether the supply pressure P detected by the sensor 92 of the remaining amount grasping unit 90 is equal to or lower than a predetermined lower limit pressure PL (second lower limit value). Here, if the supply pressure P is higher than the lower limit pressure PL, there is a sufficient amount of fluid remaining in the discharge device 30, and there is no need to replenish the discharge device 30 with fluid. Therefore, in this case, the control device 200 waits in step 3-2. On the other hand, if the supply pressure P is equal to or lower than the lower limit pressure PL, the remaining amount of fluid in the discharge device 30 is low. In this case, the control device 200 advances the control flow to step 3-3.

[0105] (Step 3-3) In step 3-3, the control device 200 pressurizes the buffer tank 50. As a result, the control device 200 exerts a pressurizing force on the fluid in the buffer tank 50, and discharges the fluid from the buffer tank 50 toward the discharge device 30 through the supply path 40. Specifically, the control device 200 controls the volume fluctuation mechanism 54 provided in the buffer tank 50 to move the piston portion 62 in a direction in which the volume of the communication space 58 communicating with the supply path 40 decreases. More specifically, the control device 200 supplies gas to the solenoid valve 72b from the supply source 72a while setting the solenoid valve 72b provided in the drive unit 64 to the first state. As a result, the gas compressed from the supply source 72a, which is an air compressor or the like, is introduced from the solenoid valve 72b through the pilot check valve 72c to the first space 70a of the casing 68 through the first casing connection port 68a. Accordingly, the partition wall 70 and the piston portion 62 are actuated, and the piston portion 62 moves in a direction that reduces the volume of the communication space 58. In this manner, the control device 200 pressurizes the buffer tank 50. When the buffer tank 50 is in a pressurized state, the fluid stored in the communication space 58 is discharged toward the discharge device 30 via the supply path 40.

[0106] (Step 3-4) In step 3-4, the control device 200 checks whether the remaining amount of fluid in the buffer tank 50 has decreased to the lower limit. If the remaining amount of fluid in the buffer tank 50 has decreased to the lower limit, the control flow proceeds to step 3-5, and if the remaining amount of fluid has not reached the lower limit, the control flow proceeds to step 3-6.

[0107] (Step 3-5) In step 3-5, the control device 200 stops discharging the fluid from the buffer tank 50. Specifically, the control device 200 places the buffer tank 50 in a holding state in the same manner as in step 2-11 described above. Thereafter, the control device 200 completes a series of control flows.

[0108] (Step 3-6) In step 3-6, the control device 200 checks whether or not the discharge device 30 is filled with a sufficient amount of fluid. Specifically, the control device 200 checks whether or not the supply pressure P has reached a predetermined upper limit pressure PH (second upper limit value). Here, if the supply pressure P is less than the upper limit pressure PH, the control device 200 returns the control flow to step 3-4. On the other hand, if the supply pressure P is equal to or greater than the upper limit pressure PH, the control device 200 advances the control flow to step 3-7.

[0109] (Step 3-7) In step 3-7, the controller 200 sets the buffer tank 50 to the holding state in the same manner as in steps 2-11 and 3-5 described above. After that, the controller 200 advances the control flow to step 3-8.

[0110] (Step 3-8) In step 3-8, the control device 200 checks the fluid storage state in the buffer tank 50. As a result, if the amount of fluid stored in the buffer tank 50 is greater than the lower limit, the control device 200 returns the control flow to step 3-2. On the other hand, if the amount of fluid stored in the buffer tank 50 is equal to the lower limit, operation in the tank supply mode cannot be continued any further, and the control flow is terminated.

[0111] (4) Composite supply mode Next, the combined supply mode will be described in detail. The combined supply mode is an operation mode in which fluid is supplied to the discharge device 30 from both the pump 20 and the buffer tank 50. The operation in the combined supply mode is an operation mode performed for the purpose of supplementing the supply of fluid from the buffer tank 50 to the discharge device 30 with the supply of fluid from the pump 20 when it is assumed that the remaining amount of fluid in the tank section 52 is getting low, for example, at the end of the above-mentioned tank supply mode. If the operation in the combined supply mode is performed when it is assumed that the remaining amount of fluid in the tank section 52 is getting low, it is possible to both stabilize the supply pressure of the fluid to the discharge device 30 and use up the fluid accumulated in the buffer tank 50.

[0112] That is, when the remaining amount of fluid in the buffer tank 50 decreases in the tank supply mode, the distance between the bottom surface of the tank main body 52a and the piston 62 becomes narrower, and the pressure loss increases. As a result, the flow rate of the fluid discharged from the buffer tank 50 to the discharge device 30 decreases. When the flow rate of the fluid from the buffer tank 50 to the discharge device 30 falls below the discharge rate of the fluid in the discharge device 30, a shortage of the supply of the fluid occurs. Therefore, when the remaining amount of the fluid stored in the buffer tank 50 falls below a certain amount, the operation mode is switched to the combined supply mode, and the pump 20 is operated in addition to the buffer tank 50 to supply the fluid, so that the supply pressure of the fluid to the discharge device 30 can be stabilized while the fluid stored in the buffer tank 50 can be used up.

[0113] In the combined supply mode, as shown in the operation explanatory diagram of FIG. 15 and the timing chart of FIG. 16, the operation of the pump 20 and the buffer tank 50 is controlled based on the measurement value of the remaining amount grasping unit 90. Specifically, in the combined supply mode, when supplying the fluid to the discharge device 30, the operation is controlled so that both the pump 20 and the buffer tank 50 supply the fluid toward the discharge device 30 on condition that the measurement value of the remaining amount grasping unit 90 falls below a predetermined lower limit value. More specifically, the control device 200 pressurizes the buffer tank 50 and operates the pump 20 with the valve 48 in an open state on condition that the supply pressure P detected by the sensor 92 falls below a predetermined lower limit pressure PL. As a result, the control device 200 supplies the fluid to the discharge device 30 from both the buffer tank 50 and the pump 20. When fluid is supplied by both the pump 20 and the buffer tank 50 in the combined supply mode, it is possible to adjust whether the fluid present in the pump 20 or the buffer tank 50 is used preferentially by differentiating the timing at which the pump 20 and the buffer tank 50 start pumping the fluid. In this embodiment, in order to prevent deterioration of the fluid accumulated in the buffer tank 50, and to satisfy the desire to reliably use up the fluid in the buffer tank 50 in each cycle, the control device 200 performs control to delay the timing at which the pump 20 starts pumping the fluid relative to the timing at which the buffer tank 50 starts pumping the fluid.

[0114] On the other hand, in the combined supply mode, the pump 20 and the buffer tank 50 are controlled to stop discharging the fluid on the condition that the measurement value of the remaining amount grasping unit 90 exceeds a predetermined upper limit value. More specifically, in the combined supply mode, the pump 20 is stopped and the buffer tank 50 is put into a holding state on the condition that the supply pressure P detected by the sensor 92 exceeds a predetermined upper limit pressure PH. This prevents the fluid from being excessively supplied to the discharge device 30 that is sufficiently filled with the fluid.

[0115] In the combined supply mode, the above-mentioned operations are performed in accordance with the flowchart shown in Fig. 17. Hereinafter, the operation of the fluid discharge system 10 in the combined supply mode will be described in further detail with reference to the flowchart in Fig. 17.

[0116] (Step 4-1) In step 4-1, timing is started by a timer provided in the control device 200. Thereafter, the control device 200 advances the control flow to step 4-2.

[0117] (Step 4-2) In step 4-2, the control device 200 checks whether the time measured by the timer (hereinafter also referred to as timer time Ty) is equal to or longer than a predetermined time T1. Here, the predetermined time T1 is a time measured to determine when to end the composite supply mode. By using the predetermined time T1 as a judgment condition in step 4-2, instead of providing limit switches or the like at two locations, one just before the lower limit of the buffer tank 50 and the other at the lower limit, a configuration can be adopted in which a limit switch or the like is provided only just before the lower limit of the buffer tank 50. Specifically, if operation is continued after the timing at which the remaining amount of fluid is detected by a sensor provided just before the lower limit of the buffer tank 50, the predetermined time T1 is determined based on the time at which the buffer tank 50 is expected to become empty, thereby making it possible to end the composite supply mode at an appropriate timing. In this way, instead of providing limit switches at two locations, one just before the lower limit of the buffer tank 50 and the other at the lower limit, the composite supply mode is terminated using the predetermined time T1 as an index after the fluid is detected just before the lower limit of the buffer tank 50. This has the advantage that it is possible to suppress the occurrence of a problem such as the composite supply mode never ending even if the liquid hardens at the bottom of the buffer tank 50 and the piston does not fully descend. Here, when it is confirmed that the timer time Ty is equal to or greater than the predetermined time T1, the control device 200 completes the control flow. On the other hand, when the timer time Ty is less than the predetermined time T1, the control device 200 advances the control flow to step 4-3.

[0118] (Step 4-3) In step 4-3, the control device 200 checks the supply pressure P to the discharge device 30. If the supply pressure P is higher than a predetermined lower limit pressure PL, the control flow returns to step 4-2. On the other hand, if the supply pressure P is equal to or lower than the lower limit pressure PL, the control device 200 advances the control flow to step 4-4.

[0119] (Step 4-4) In step 4-4, the control device 200 pressurizes the buffer tank 50 in the same manner as in step 3-3 described above. This causes a pressurizing force to act on the fluid in the buffer tank 50, and the fluid is supplied from the buffer tank 50 to the discharge device 30. Thereafter, the control device 200 advances the control flow to step 4-5.

[0120] (Step 4-5) In step 4-5, the control device 200 checks the time that has elapsed since the buffer tank 50 was pressurized in step 4-4 (hereinafter also referred to as "pressurization time Tp"). The predetermined time T3 corresponds to a delay time that delays the timing at which the pump 20 starts pumping the fluid relative to the timing at which the buffer tank 50 starts pumping the fluid in the combined supply mode. While the pressurization time Tp is less than the predetermined time T3, the control device 200 keeps the control flow on hold in step 4-5. When the pressurization time Tp becomes equal to or greater than the predetermined time T3, the control device 200 advances the control flow to step 4-6.

[0121] (Step 4-6) In step 4-6, the control device 200 operates the pump 20 to supply the fluid to the discharge device 30. At this time, the supply of the fluid to the discharge device 30 by the buffer tank 50, which has already started in the above step 4-4, is also continued. Therefore, by operating the pump 20 in step 4-6, the fluid is supplied to the discharge device 30 by both the buffer tank 50 and the pump 20. When the operation of the pump 20 is started, the control device 200 advances the control flow to step 4-7.

[0122] (Step 4-7) In step 4-7, the control device 200 checks the timer time Ty that started to be measured in step 4-1. If the timer time Ty is equal to or greater than the predetermined time T1, the control device 200 advances the control flow to step 4-8. If the timer time Ty is less than the predetermined time T1, the control device 200 advances the control flow to step 4-9.

[0123] (Step 4-8) In step 4-8, the control device 200 stops the pump 20 and sets the buffer tank 50 to the holding state. The control for setting the buffer tank 50 to the holding state is performed in the same manner as in step 2-11 described above. As a result, the supply of fluid to the discharge device 30 is stopped in both the pump 20 and the buffer tank 50. Thereafter, the control device 200 completes the control flow.

[0124] (Step 4-9) In step 4-9, the control device 200 checks the supply pressure P to the discharge device 30. If the supply pressure P is less than the predetermined upper limit pressure PH, the control flow returns to step 4-7. On the other hand, if the supply pressure P is equal to or greater than the upper limit pressure PH, the control device 200 advances the control flow to step 4-10.

[0125] (Step 4-10) In step 4-10, similarly to step 4-8, the controller 200 stops the pump 20 and sets the buffer tank 50 to a holding state. After that, the controller 200 advances the control flow to step 4-11.

[0126] (Step 4-11) In step 4-11, the control device 200 checks the timer time Ty that started to be measured in step 4-1. If the timer time Ty is equal to or greater than the predetermined time T1, the control device 200 ends the series of control flows. If the timer time Ty is less than the predetermined time T1, the control device 200 returns the control flow to step 4-3.

[0127] As described above, the fluid discharge system 10 can be operated in four operation modes consisting of (1) pump supply mode, (2) tank accumulation mode, (3) tank supply mode, and (4) combined supply mode. Next, the overall operation of the fluid discharge system 10 realized by sequentially operating in these operation modes will be described. The overall operation of the fluid discharge system 10 can be performed in either a first operation pattern in which the fluid is accumulated in the buffer tank 50 in the initial stage, or a second operation pattern in which the fluid is accumulated in the buffer tank 50 in the intermediate stage. Therefore, in the following description, the operation in the first operation pattern will be described first, and then the operation in the second operation pattern will be described.

[0128] [Overall operation of the fluid discharge system 10 according to the first operation pattern] The first operation pattern is an operation pattern in which operation in each operation mode is repeated in the order of tank accumulation mode → pump supply mode → tank supply mode → composite supply mode. A mode switching condition for switching from an operation in each operation mode to an operation in the next operation mode is set for each operation mode. The control device 200 controls switching of the operation mode every time the mode switching condition is satisfied. When the fluid discharge system 10 operates in the first operation pattern, the control device 200 controls the operation of the fluid discharge system 10 in accordance with the flowchart shown in FIG. 18 and the timing chart shown in FIG. 19. The operation of the fluid discharge system 10 in the first operation pattern will be described in more detail below with reference to FIG. 18 and FIG. 19.

[0129] (Step 5-1) In step 5-1, the control device 200 starts operation in the tank accumulation mode in accordance with the control flow of Fig. 11. Thereafter, the control device 200 advances the control flow to step 5-2.

[0130] (Step 5-2) In step 5-2, the control device 200 checks the remaining amount of fluid stored in the buffer tank 50 in the fluid discharge system 10 operating in the tank accumulation mode. If it is confirmed that the amount of accumulated fluid in the buffer tank 50 has reached the upper limit, the control device 200 advances the control flow to step 5-3.

[0131] (Step 5-3) In step 5-3, the controller 200 starts operation in the pump supply mode in accordance with the control flow of Fig. 8. Thereafter, the controller 200 advances the control flow to step 5-4.

[0132] (Step 5-4) In step 5-4, the control device 200 checks the remaining amount of fluid in the reservoir 22 of the pump 20 in the fluid discharge system 10 operating in the pump supply mode. If it is confirmed that the remaining amount of fluid in the reservoir 22 has reached a lower limit, the control device 200 advances the control flow to step 5-5.

[0133] (Step 5-5) In step 5-5, the controller 200 starts operation in the tank supply mode in accordance with the control flow of Fig. 14. Thereafter, the controller 200 advances the control flow to step 5-6.

[0134] (Step 5-6) In step 5-6, the control device 200 checks the remaining amount of fluid in the buffer tank 50 in the fluid discharge system 10 operating in the tank supply mode. If it is confirmed that the remaining amount of fluid in the buffer tank 50 has reached its lower limit, the control device 200 advances the control flow to step 5-7. In this step, the state in which "the remaining amount of fluid in the buffer tank 50 has reached its lower limit" may be defined as a state in which the amount of fluid stored has decreased to a level at which the fluid cannot be supplied, but in this embodiment, the control device 200 defines a stage slightly before the level at which the fluid cannot be supplied (a state in which a small amount of fluid remains) as a case in which the remaining amount of fluid is at the lower limit, and performs operation control.

[0135] (Step 5-7) In step 5-7, the control device 200 starts the operation in the composite supply mode in accordance with the control flow of Fig. 17. Thereafter, the control device 200 advances the control flow to step 5-8.

[0136] (Step 5-8) In step 5-8, the control device 200 checks the timer time Ty in the fluid delivery system 10 operating in the combined supply mode. If it is determined that the timer time Ty is equal to or greater than the predetermined time T1, the control device 200 returns the control flow to step 5-1.

[0137] When the fluid discharge system 10 operates in the first operation pattern, the operation is controlled by the control device 200 in accordance with the above-mentioned flow. As described above, the first operation pattern accumulates the fluid in the buffer tank 50 in the initial stage (step 5-1). Therefore, when the fluid discharge system 10 is operated in the first operation pattern, the fluid accumulated in the buffer tank 50 can be supplied to the discharge device 30 not only when the fluid in the storage section 22 of the pump 20 runs out, but also in cases where the pump 20 is unable to supply the fluid due to an abnormality occurring in the pump 20, for example.

[0138] [Overall operation of the fluid discharge system 10 according to the second operation pattern] Next, the overall operation of the fluid discharge system 10 according to the second operation pattern will be described. The second operation pattern is an operation pattern in which operation in each operation mode is repeated in the order of pump supply mode → tank accumulation mode → tank supply mode → composite supply mode. In the second operation pattern, a mode switching condition for switching from operation in each operation mode to operation in the next operation mode is also set for each operation mode. The control device 200 controls switching of the operation mode every time the mode switching condition is satisfied. When the fluid discharge system 10 operates in the second operation pattern, the control device 200 controls the operation of the fluid discharge system 10 according to the flowchart shown in FIG. 20. Hereinafter, the operation of the fluid discharge system 10 according to the second operation pattern will be described in more detail with reference to FIG. 20.

[0139] (Step 6-1) In step 6-1, the controller 200 starts operation in the pump supply mode in accordance with the control flow of Fig. 8. Thereafter, the controller 200 advances the control flow to step 6-2.

[0140] (Step 6-2) In step 6-2, the control device 200 checks the remaining amount of fluid in the reservoir 22 of the pump 20 in the fluid discharge system 10 operating in the pump supply mode. If it is confirmed that the remaining amount of fluid in the reservoir 22 is about to reach the lower limit, the control device 200 advances the control flow to step 6-3.

[0141] (Step 6-3) In step 6-3, the controller 200 starts operation in the tank accumulation mode in accordance with the control flow of Fig. 11. Thereafter, the controller 200 advances the control flow to step 6-4.

[0142] (Step 6-4) In step 6-4, the control device 200 checks the remaining amount of fluid in the storage section 22 in the fluid discharge system 10 operating in the tank accumulation mode. If it is confirmed that the accumulated amount of fluid in the storage section 22 has reached the lower limit, the control device 200 advances the control flow to step 6-5.

[0143] (Step 6-5) In step 6-5, the controller 200 starts operation in the tank supply mode in accordance with the control flow of Fig. 14. Thereafter, the controller 200 advances the control flow to step 6-6.

[0144] (Step 6-6) In step 6-6, the control device 200 checks the remaining amount of fluid in the buffer tank 50 in the fluid discharge system 10 operating in the tank supply mode. Here, when it is confirmed that the remaining amount of fluid in the buffer tank 50 has reached the lower limit, the control device 200 advances the control flow to step 6-7. In this step, the state in which "the remaining amount of fluid in the buffer tank 50 has reached the lower limit" may be a state in which the storage amount has decreased to a level at which the fluid cannot be supplied, but in this embodiment, the control device 200 defines a stage slightly before the level at which the fluid cannot be supplied (a state in which a small amount of fluid remains) as a case in which the remaining amount of fluid is at the lower limit, and performs operation control.

[0145] (Step 6-7) In step 6-7, the control device 200 starts the operation in the composite supply mode in accordance with the control flow of Fig. 17. Thereafter, the control device 200 advances the control flow to step 6-8.

[0146] (Step 6-8) In step 6-8, the controller 200 checks the timer time Ty in the fluid delivery system 10 operating in the combined supply mode. If it is determined that the timer time Ty is equal to or greater than the predetermined time T1, the controller 200 returns the control flow to step 6-1.

[0147] When the fluid discharge system 10 operates in the second operation pattern, the control device 200 controls the operation in accordance with the above-mentioned flow. As described above, in the second operation pattern, prior to the operation in the tank accumulation mode, the operation in the pump supply mode is performed, and in the intermediate stage (step 6-3), the fluid is accumulated in the buffer tank 50 in the tank accumulation mode. In this way, when the fluid discharge system 10 is operated in the second operation pattern, the fluid is accumulated in the buffer tank 50 at a stage before the remaining amount of the fluid in the storage section 22 of the pump 20 reaches the lower limit, and the supply source of the fluid to the discharge device 30 is switched to the buffer tank 50. Therefore, according to the second operation pattern, the period during which the fluid is accumulated (remains) in the buffer tank 50 can be minimized.

[0148] As described above, the fluid discharge system 10 of this embodiment is configured to have, in addition to the pump 20 and the discharge device 30, a buffer tank 50 disposed in the middle of the supply path 40 connecting the pump 20 and the discharge device 30. The fluid discharge system 10 is configured to be capable of realizing a pressure acting state in which the buffer tank 50 exerts pressure on the fluid. In addition, the fluid discharge system 10 is configured to be capable of realizing a pressurized state in which a pressurizing force is exerted on the fluid and a depressurized state in which a depressurizing force is exerted on the fluid as the pressure acting state. Therefore, the fluid discharge system 10 of this embodiment can pressure-feed the fluid toward the discharge device 30 when pressure is exerted toward the outside of the buffer tank 50 in the pressurized state. Therefore, the fluid discharge system 10 can suppress pressure fluctuations caused by switching the supply source of the fluid to the discharge device 30 from the pump 20 to the buffer tank 50.

[0149] Furthermore, when the buffer tank 50 is in a decompressed state and pressure is applied to the fluid in a direction toward the inside of the buffer tank 50, the fluid discharge system 10 can smoothly suck the fluid into the buffer tank 50. This allows the fluid discharge system 10 to suck and accumulate the fluid in the buffer tank 50 in preparation for supplying the fluid from the buffer tank 50 to the discharge device 30. Therefore, the fluid discharge system 10 can contribute to a stable supply of fluid to the discharge device 30 by utilizing the fluid accumulation function of the buffer tank 50.

[0150] In the fluid discharge system 10 of this embodiment, the buffer tank 50 can realize a holding state in which no pressure is applied to the fluid, in addition to the above-mentioned pressure acting state (pressurized state, reduced pressure state). Therefore, in a state in which the discharge device 30 can discharge the fluid without using the buffer tank 50, such as during operation in the pump supply mode or when the remaining amount of fluid in the discharge device 30 is sufficient, or in a state in which it is not appropriate to continue accumulating liquid in the buffer tank 50 considering the remaining amount of fluid in the discharge device 30 during operation in the tank accumulation mode, it is possible to suppress fluctuations in the supply pressure of the fluid to the discharge device 30 and fluctuations in the discharge pressure of the fluid in the discharge device 30 due to the influence of the buffer tank 50. Therefore, according to the fluid discharge system 10 of this embodiment, it is possible to suppress fluctuations in the supply pressure of the fluid to the discharge device 30 and fluctuations in the discharge pressure in the discharge device 30 due to pressure acting on the fluid from the buffer tank 50.

[0151] The fluid discharge system 10 of this embodiment can stably supply fluid to the discharge device 30 by operating in each of the above-mentioned operation modes without providing multiple pumps 20. Therefore, the fluid discharge system 10 of this embodiment can suppress an increase in installation space and cost compared to a configuration in which multiple pumps 20 are provided.

[0152] In this embodiment, the pressure acting state exerting pressure on the fluid in the buffer tank 50 is an example in which the pressure is changed in three stages, including a pressurized state in which a positive pressure acts on the fluid from the buffer tank 50 side toward the supply path 40 side, a reduced pressure state in which a negative pressure acts on the fluid from the buffer tank 50 side toward the supply path 40 side, and a holding state in which no pressure acts on the fluid, but the present invention is not limited to this. For example, in the pressurized state or reduced pressure state, the pressure acting state of the pressure acting on the fluid may be changed in multiple stages, or the pressure acting state may be changed steplessly.

[0153] Specifically, as described above, in the volume fluctuation mechanism 54, instead of providing the solenoid valve 72b, the pilot check valve 72c, and the first speed controller 72d in the first piping system 74 connected to the first casing connection port 68a of the casing 68, it is preferable to provide, for example, a regulator 72x as shown in FIG. 22. With this configuration, it is possible to change the pressure acting on the fluid in a multi-step or stepless manner in a pressurized or reduced pressure state. Also, with this configuration, for example, in the tank accumulation mode described above, instead of putting the buffer tank 50 in a reduced pressure state, it is possible to change the pressure acting on the fluid from a strong pressurized state to a weak pressurized state, thereby further optimizing the pressure control in the buffer tank 50 according to the operating state of the fluid discharge system 10.

[0154] In the above-mentioned fluid discharge system 10, the buffer tank 50 includes a tank portion 52 and a volume change mechanism 54, and the volume change mechanism 54 controls the increase and decrease in the volume of the communication space 58, thereby enabling the buffer tank 50 to be in a pressurized state, a depressurized state, or a holding state. Therefore, the fluid discharge system 10 can control the operation of the buffer tank 50 by controlling the increase and decrease in the volume of the communication space 58.

[0155] As described above, in the fluid discharge system 10, the volume fluctuation mechanism 54 includes the piston portion 62 that separates the inside of the tank portion 52 into the communication space 58 and the non-communicating space 60 that is not connected to the supply path 40, and the drive portion 64 that moves the piston portion 62. In addition, the buffer tank 50 is capable of realizing a pressurized state, a depressurized state, and a holding state by controlling the movement of the piston portion 62 with the drive portion 64. Therefore, the fluid discharge system 10 can appropriately realize a pressurized state, a depressurized state, and a holding state by controlling the movement of the piston portion 62, and can stably supply the fluid to the discharge device 30. Note that, in the present embodiment, an example is shown in which the piston portion 62 is provided and pressure is applied to the fluid through the piston portion 62, but the present invention is not limited to this. For example, the volume fluctuation mechanism 54 may be configured to directly apply pressure to the fluid, and may be configured without the piston portion 62.

[0156] In this embodiment, the driving unit 64 is configured by a gas cylinder device (air cylinder device in this embodiment) capable of generating a driving force by the inflow and outflow of gas (air), but the present invention is not limited to this. For example, the fluid discharge system 10 may be configured by a hydraulic cylinder device using oil as a fluid and capable of generating a driving force by hydraulic pressure, or a driving device 64x (see FIG. 23) capable of generating a driving force mechanically or electrically by using a motor or the like.

[0157] The present invention is not limited to the above-mentioned embodiment and modified examples, and other embodiments may be made within the scope of the claims, based on the teachings and spirit of the invention. For example, the above-mentioned buffer tank 50 has a connection part 56 connected to the supply path 40 at one end of the tank part 52, and the fluid flows in and out of the tank main body part 52a through the connection part 56, but it can be replaced with a buffer tank 150 as shown in FIG. 22. The buffer tank 150 has a substantially identical configuration to the above-mentioned buffer tank 50, but differs in that a connection port 56c serving as an inlet for the fluid to the tank main body part 52a is provided above the connection port 56b serving as an outlet for the fluid in the tank main body part 52a. With such a configuration, the retention time of the fluid can be minimized, and the accumulated fluid can be used up even more.

[0158] In addition, in the above-mentioned fluid discharge system 10, in the tank accumulation mode, as a measure to suppress the drop in the supply pressure P to the discharge device 30, the accumulation of the fluid in the buffer tank 50 is set to a time limit, but the present invention is not limited to this. For example, the accumulation of the fluid in the buffer tank 50 may be stopped on the condition that the supply pressure P to the discharge device 30 becomes equal to or lower than a predetermined value. In addition, in the tank accumulation mode, the fluid discharge system 10 may improve the fluid supply capacity of the pump 20 compared to the case of operating in other operation modes, or may advance the operation start time of the pump 20 from the timing exemplified in the above embodiment, thereby suppressing the drop in the supply pressure P. In addition, the amount of accumulated fluid in the buffer tank 50 can be directly or indirectly derived and grasped by, for example, a method of directly measuring and deriving the amount of fluid using a remaining amount sensor, a method of detecting and subtracting the amount of fluid flowing into and out of the buffer tank 50, or the like, or indirectly grasped by the time when the fluid flows in and out of the buffer tank 50.

[0159] In addition, in the above-mentioned fluid discharge system 10, in the combined supply mode, the supply of fluid from the buffer tank 50 is started, and then the pump 20 is operated after a while, thereby preferentially consuming the fluid in the buffer tank 50, but the present invention is not limited to this. In the combined supply mode, for example, the rotation speed of the pump 20 may be reduced to reduce the pumping capacity, or the pressure of the buffer tank 50 may be increased to provide a difference in the fluid supply capacity between the pump 20 and the buffer tank 50, thereby preferentially consuming the fluid in the buffer tank 50. Note that, when the pumping capacity of the pump 20 is reduced as described above, the supply of fluid from the buffer tank 50 and the supply of fluid by the operation of the pump 20 may be started simultaneously.

[0160] Here, the above-mentioned fluid discharge system 10 may be configured such that a sensor such as a limit switch is installed only slightly before the lower limit of the buffer tank 50 (slightly before the remaining amount of fluid becomes zero), and when the sensor detects that the remaining amount of fluid in the buffer tank 50 is at the lower limit (corresponding to steps 5-6 and 6-6), the operation mode is switched to the combined supply mode (steps 5-7 and 6-7). In this case, the determination of switching from the combined supply mode to the next operation mode may be performed by a timer (steps 5-8 and 6-8), so that the remaining amount of fluid in the buffer tank 50 has reached the lower limit. Also, instead of determining the switching from the combined supply mode to the next operation mode in this manner, a sensor may be separately provided at the lower limit position of the buffer tank 50, and the combined supply mode may be switched to the next operation mode on the condition that the sensor detects that the fluid has decreased to the lower limit position. In addition, the state where "the remaining amount of fluid in the buffer tank 50 is at its lower limit" may be a state where the amount of fluid stored has decreased to a level where the fluid cannot be supplied, but the present invention is not limited to this and can be appropriately defined within the scope of the present invention. Specifically, as explained in this embodiment, even if a state just before the level where the fluid cannot be supplied (a state where a small amount of fluid remains) is defined as "the remaining amount of fluid in the buffer tank 50 is at its lower limit", it does not deviate from the scope of the present invention.

[0161] The above-mentioned fluid discharge system 10 is provided with a sensor 92 capable of detecting pressure between the buffer tank 50 and the discharge device 30, and controls each device based on the supply pressure P to the discharge device 30, but the present invention is not limited to this. For example, the sensor 92 may be a flow rate sensor or the like, and may grasp the remaining amount of fluid in the discharge device 30 according to the flow rate of the fluid supplied to the discharge device 30. In addition, when a separate accumulator is provided before the discharge device 30, it is preferable to grasp the remaining amount of fluid in the discharge device 30 based on the piston position of this accumulator and control each device. In addition, the fluid discharge system 10 is not limited to the above-mentioned arrangement of the sensor 92. Specifically, the sensor 92 is not limited to the supply path 40 or the accumulator, and may be provided in the discharge device 30 itself (for example, the casing 100 or the stator 104 of the discharge device 30).

[0162] As described above, the fluid discharge system 10 may, for example, be provided with a remaining amount sensor in the buffer tank 50, or a position sensor capable of detecting the position of the partition wall 70, and determine the amount of fluid stored in the buffer tank 50 based on the output values ​​from these sensors, or may be capable of detecting or deriving the amount of fluid flowing into and out of the buffer tank 50, and determine the amount of fluid stored in the buffer tank 50 based on the amount of fluid flowing in and out. In addition, the fluid discharge system 10 is not limited to a configuration in which sensors are provided at the upper limit position or lower limit position of the buffer tank 50 and the amount of fluid stored in multiple stages can be detected, and it is also possible to have a configuration in which the amount of fluid stored in the buffer tank 50 can be detected continuously.

[0163] Specifically, as a device capable of continuously detecting the amount of fluid stored in the buffer tank 50, for example, as shown in Fig. 24, a detection device 300 for continuously detecting the amount of fluid stored in the buffer tank 50 may be provided. The detection device 300 shown in Fig. 24 detects the remaining amount of fluid in the buffer tank 50 by continuously detecting the position of a member (piston portion 62 in the illustrated example) that moves according to the remaining amount of fluid, or a rod portion 66 or partition wall 70 that moves in conjunction with the member, thereby detecting the remaining amount of fluid. In the example shown in Fig. 24, the detection device 300 includes a sensor dog 302 and a magnetic position detection sensor 304.

[0164] The sensor dog 302 is formed to emit magnetism, for example, by incorporating a magnet. The sensor dog 302 can be attached to an object whose position is to be detected. The sensor dog 302 is attached to a position variable member 306 whose position varies depending on the remaining amount of fluid in the buffer tank 50, such as the piston portion 62, rod portion 66, and partition wall 70 that constitute a cylinder in the buffer tank 50. In the example shown in FIG. 24, the rod portion 66 is selected as the position variable member 306, and the sensor dog 302 is attached to the rod portion 66.

[0165] The magnetic position detection sensor 304 is a sensor that can detect the position of the sensor dog 302 based on the magnetism emitted from the sensor dog 302. The magnetic position detection sensor 304 is attached to the buffer tank 50 so that the range in which the sensor dog 302 moves in response to an increase or decrease in the amount of fluid stored in the buffer tank 50 becomes the detection range. In this embodiment, the magnetic position detection sensor 304 is attached to the casing 68 of the buffer tank 50 over the entire movement range in which the sensor dog 302 is expected to move in response to an increase or decrease in the amount of fluid. In this embodiment, since the sensor dog 302 moves in the axial direction of the buffer tank 50, the magnetic position detection sensor 304 is arranged to extend in the axial direction of the buffer tank 50.

[0166] 24, the fluid discharge system 10 can grasp the remaining amount of fluid in the buffer tank 50 by relating the tank volume (remaining amount of fluid) of the buffer tank 50 to the stroke of the cylinder, thereby detecting the remaining amount of fluid in the buffer tank 50. In other words, the amount of fluid stored in the buffer tank 50 can be continuously detected by the detection device 300.

[0167] 24, the upper limit and lower limit of the amount of fluid stored in the buffer tank 50 can be appropriately set or changed to control the operation of the fluid discharge system 10. Specifically, when a detection device such as a limit switch or a sensor is provided at the positions of the upper limit and lower limit of the amount of fluid stored in the buffer tank 50 as in the above embodiment, the installation position of the detection device needs to be physically moved in order to change the upper limit and lower limit of the amount of fluid stored. However, by using the above-mentioned detection device 300, the upper limit and lower limit positions can be set at appropriate positions within the range where the magnetic position detection sensor 304 can detect the sensor dog 302, or the positions of the upper limit and lower limit positions can be changed, thereby controlling the operation of the fluid discharge system 10.

[0168] In addition, in the detection device 300, it is preferable to make it possible to display the remaining amount of fluid in the buffer tank 50 on a user interface 310 such as the operation control panel of the fluid discharge system 10 or the monitor of the control device based on the position information of the sensor dog 302 detected by the magnetic position detection sensor 304.

[0169] Specifically, as shown in Fig. 25, a remaining amount display unit 312 that shows the remaining amount of fluid in the buffer tank 50 may be provided, and the remaining amount may be displayed by an indicator or a numerical value (indicator in the illustrated example). By visualizing the remaining amount of fluid in the buffer tank 50 in this manner, it becomes clear when to refill the fluid in the storage unit 22 in which the pump 20 is disposed, or when to replace the fluid 22. For example, if the storage unit 22 is a pail, it becomes clear when to replace an empty pail (storage unit 22) with a new pail (storage unit 22).

[0170] When providing a user interface 310 as shown in Fig. 25, it is preferable to provide a mode display unit 314 that displays in addition to or instead of the remaining amount of fluid in the buffer tank 50, so that it is possible to identify which operation mode the fluid discharge system 10 is operating in. In the mode display unit 314 illustrated in Fig. 25, the display indicating the current operation mode is displayed in a color that is inverted from the display indicating the other operation modes, so that it is possible to identify which operation mode the fluid discharge system 10 is operating in. This makes it possible to intuitively understand which operation mode the fluid discharge system 10 is operating in, and clearly understand the timing to replace the storage unit 22 or replenish the storage unit 22 with fluid.

[0171] The timing for replacing the storage section 22 or refilling the storage section 22 with fluid can be specified as appropriate, but in the fluid discharge system 10 according to the above embodiment, it is preferable to perform the replacement or refilling during operation in the tank supply mode. Therefore, as shown in Fig. 25, if it is clearly shown on the mode display section 314 that the operation state of the fluid discharge system 10 has become the tank supply mode, the timing for replacing the storage section 22 or refilling the storage section 22 with fluid can be clearly understood.

[0172] In addition, when providing a user interface 310 as shown in Fig. 25, it is preferable to make it possible to accept operations at a display portion such as an indicator displayed thereon (in the illustrated example, a remaining amount display portion 312) so that an operation command for each portion can be output or operation settings can be made in response to the operation. For example, in the example of Fig. 25, it is preferable to make it possible to accept operations at a display portion of an indicator in the remaining amount display portion 312 so that the length of the indicator can be adjusted. This allows an operator to intuitively perform operations such as outputting a warning or setting either or both of an upper limit and a lower limit of the remaining amount of fluid in the buffer tank 50, which are indicators of the operating conditions.

[0173] The present invention is not limited to the above-mentioned embodiments and modifications, and other embodiments may be possible within the scope of the claims. The components of the above-mentioned embodiments may be arbitrarily selected and combined. Any component of the embodiment may be arbitrarily combined with any component described in the Summary of the Invention or any component that embodies any component described in the Summary of the Invention. We intend to obtain rights to these as well through amendments to this application or divisional applications. [Industrial Applicability]

[0174] INDUSTRIAL APPLICABILITY The present invention can be suitably used in all fluid discharge systems for pumping and discharging a fluid. [Explanation of symbols]

[0175] 10: Fluid discharge system 20: Pump 22: Storage section 30:Discharge device 40: Supply route 50: Buffer tank 52: Tank section 54: Volume change mechanism 58: Communication space 60: Non-communicating space 62: Piston section (partition wall section) 64: Drive unit

Claims

1. A discharge device that discharges a fluid; a pump having a storage section and capable of supplying the fluid stored in the storage section to the discharge device by pumping the fluid; a supply passage connecting the pump and the discharge device so that a fluid can pass between them; A buffer tank disposed in the middle of the supply path and capable of suctioning and discharging the fluid; a remaining amount grasping unit that grasps the remaining amount of the fluid in the discharge device, When the supply of the fluid by the pump is limited, the buffer tank discharges the fluid accumulated therein, thereby allowing the supply of the fluid to the discharge device to be continued; This fluid discharge system is characterized by the fact that, when supplying fluid from the buffer tank, when the remaining amount of fluid in the discharge device detected by the remaining amount detecting unit is at a lower limit, the buffer tank starts supplying fluid to the discharge device by discharging the fluid accumulated inside, and when the remaining amount of fluid is at an upper limit, the buffer tank stops discharging the fluid, thereby stopping the supply of fluid.

2. The remaining amount grasping unit, a pressure detection device provided between the buffer tank and the discharge device in the supply path or in the discharge device; 2. The fluid discharge system according to claim 1, wherein a remaining amount of the fluid in the discharge device is grasped based on a measurement value of the pressure detection device.

3. When supplying a fluid to the discharge device, the buffer tank discharges the fluid on condition that the remaining amount of the fluid in the discharge device grasped by the remaining amount grasping unit falls below a predetermined lower limit, and the buffer tank stops discharging the fluid on condition that the remaining amount of the fluid in the discharge device grasped by the remaining amount grasping unit exceeds a predetermined upper limit; 3. The fluid discharge system according to claim 1, further comprising:

4. The buffer tank is capable of accumulating a fluid inside the buffer tank by sucking the fluid, 4. The fluid discharge system according to claim 1, wherein the discharge device continues to discharge the fluid while the fluid is being accumulated.

5. When accumulating the fluid in the buffer tank, the buffer tank sucks the fluid on condition that the remaining amount of the fluid in the discharge device grasped by the remaining amount grasping unit exceeds a predetermined upper limit value, and the buffer tank stops sucking the fluid on condition that the remaining amount of the fluid in the discharge device grasped by the remaining amount grasping unit falls below a predetermined lower limit value; 5. The fluid discharge system according to claim 4, further comprising:

6. The buffer tank is capable of accumulating the fluid inside the buffer tank by sucking the fluid, When the supply of the fluid by the pump is limited, the buffer tank discharges the fluid accumulated therein, thereby allowing the supply of the fluid to the discharge device to be continued; The fluid discharge system according to claim 1 or 2, characterized in that the operation of the buffer tank, both for accumulating the fluid and for supplying the fluid, is controlled based on the remaining amount of fluid in the discharge device grasped by the remaining amount grasping unit.

7. The buffer tank is When accumulating the fluid, at least one of an operation of sucking the fluid on condition that the remaining amount of the fluid in the discharge device grasped by the remaining amount grasping unit exceeds a predetermined first upper limit value, and an operation of stopping the suction of the fluid on condition that the remaining amount of the fluid in the discharge device grasped by the remaining amount grasping unit falls below a predetermined first lower limit value, The fluid discharge system of claim 6, characterized in that when supplying a fluid, at least one of the following operations is performed: discharging the fluid on condition that the remaining amount of fluid in the discharge device grasped by the remaining amount grasping unit falls below a predetermined second lower limit value, and stopping the discharge of the fluid on condition that the remaining amount of fluid in the discharge device grasped by the remaining amount grasping unit exceeds a predetermined second upper limit value.

8. The buffer tank is a position variable member whose position varies within a predetermined range according to the remaining amount of fluid; A detection device for detecting the position of the position variable member, A fluid discharge system as described in any one of claims 1 to 7, characterized in that the remaining amount of fluid in the buffer tank can be grasped based on the correlation between the capacity of the buffer tank and the position of the position variable member.

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