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; and a buffer tank 50 which is disposed in the middle of the supply passage 40. The fluid discharge system 10 can conduct operations in each mode of a tank accumulation mode in which the fluid is accumulated in the buffer tank 50, a pump supply mode in which the fluid is supplied from the pump 20 to the discharge device, a tank supply mode in which the fluid is discharged from the buffer tank 50 to be supplied to the discharge device 30, and a compound supply mode in which the fluid is supplied from the pump 20 and the buffer tank 50 to the discharge device 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fluid dispensing system that supplies a fluid to a dispensing device and dispenses it. [Background technology]

[0002] Conventionally, there have been provided pump devices capable of pumping up and pumping fluids prepared in a container such as a pail, such as the pump device disclosed in Patent Document 1 below. Also conventionally, there have been provided fluid discharge systems formed by connecting such pump devices 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 fluid to be discharged from the discharge device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-203465 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described fluid dispensing system can continue dispensing the fluid from the dispensing 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 fluid to the dispensing device is cut off. Therefore, the above-described fluid dispensing system must temporarily stop dispensing the fluid from the dispensing device and refill the pump device with fluid, etc., every time the fluid runs out of the container of the pump device.

[0005] Therefore, the inventors have investigated a fluid dispensing system in which multiple pump devices (e.g., two) are provided for one dispensing device, and the pump device capable of supplying fluid to the dispensing device can be switched as needed. As a result, it has been discovered that a fluid dispensing system configured in this way can switch the connection of the dispensing device to a pump device that is ready for fluid when the pump device connected to the dispensing device runs out of fluid, thereby minimizing the interruption of fluid dispensing. However, it has been discovered that such a configuration requires a large installation space and increases costs due to the multiple pump devices (e.g., two) provided for one dispensing device.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fluid dispensing system that can stably supply a fluid to a dispensing 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 that discharges fluid, a pump having a storage section and capable of supplying fluid to the discharge device by pressurizing the fluid stored in the storage section, a supply path connecting the discharge device and the pump so that the fluid can pass between them, and a buffer tank positioned in the supply path and capable of sucking and discharging the fluid, and is characterized in that it can operate in a tank accumulation mode in which the fluid is sucked into the buffer tank and accumulated therein, a pump supply mode in which the discharge of fluid by the buffer tank is restricted and the fluid is supplied from the pump to the discharge device, a tank supply mode in which the supply of fluid to the discharge device by the pump is restricted and the fluid is discharged from the buffer tank and supplied to the discharge device, and a combined supply mode in which the fluid is supplied to the discharge device from both the pump and the buffer tank.

[0008] The fluid dispensing system of the present invention is configured to include a buffer tank in a supply path connecting the dispensing device and the pump. The fluid dispensing system of the present invention can operate not only in a pump supply mode in which the fluid is supplied from the pump to the dispensing device, but also by utilizing the buffer tank. Specifically, the fluid dispensing system of the present invention can operate in a tank accumulation mode in which the fluid is drawn into the buffer tank and accumulated therein, a tank supply mode in which the supply of fluid to the dispensing device by the pump is limited and the fluid is discharged from the buffer tank and supplied to the dispensing device, and a combined supply mode in which the fluid is supplied to the dispensing device from both the pump and the buffer tank. Therefore, by sequentially operating in various operating modes, the fluid dispensing system of the present invention can utilize the pump and the buffer tank in a complementary manner to supply fluid to the dispensing device, thereby achieving a stable supply of fluid to the dispensing device.

[0009] (2) The fluid discharge system of the present invention may be configured to switch to the combined supply mode while operating in the tank supply mode, provided that the remaining amount of fluid in the buffer tank falls below a predetermined value.

[0010] According to this configuration, the fluid can be supplied to the discharge device by switching to the combined supply mode before the fluid in the buffer tank is used up during operation in the tank supply mode. This prevents the fluid from being unable to be supplied to the discharge device during operation in the tank supply mode. Therefore, the above-described configuration allows for a stable supply of the fluid to the discharge device.

[0011] (3) The fluid delivery system of the present invention may transition to operation in the tank supply mode while operating in the pump supply mode if the amount of fluid remaining in the storage section of the pump falls below a predetermined value; transition to operation in the combined supply mode while operating in the tank supply mode if the amount of fluid remaining in the buffer tank falls below a predetermined value; transition to operation in the tank accumulation mode while operating in the combined supply mode if the amount of fluid remaining in the buffer tank reaches a lower limit; and transition to operation in the pump supply mode while operating in the tank accumulation mode if the amount of fluid remaining in the buffer tank exceeds a predetermined value.

[0012] The fluid dispensing system of the present invention can switch to a tank supply mode while operating in the pump supply mode if the remaining amount of fluid in the pump's reservoir falls below a predetermined value. Therefore, the fluid dispensing system of the present invention can switch to the tank supply mode before the pump can no longer supply fluid to the dispensing device, thereby stably continuing the supply of fluid to the dispensing device. Furthermore, the fluid dispensing system of the present invention can switch to a combined supply mode while operating in the tank supply mode if the remaining amount of fluid in the buffer tank falls below a predetermined value. This allows the fluid dispensing system of the present invention to switch to a combined supply mode before the buffer tank can no longer supply fluid to the dispensing device, thereby stably continuing the supply of fluid to the dispensing device. Furthermore, the fluid dispensing system of the present invention can switch to a tank accumulation mode while operating in the combined supply mode if the remaining amount of fluid in the buffer tank reaches a lower limit. This allows the fluid to accumulate in the buffer tank in preparation for the next time the buffer tank is used to supply fluid to the dispensing device. Furthermore, the fluid dispensing system of the present invention can switch to operation in the pump supply mode when the remaining amount of fluid in the buffer tank exceeds a predetermined value while operating in the tank accumulation mode. By sequentially switching between the operation modes in this way, the fluid dispensing system of the present invention can utilize the pump and the buffer tank in a complementary manner to supply fluid to the dispensing device, thereby achieving a stable supply of fluid to the dispensing device.

[0013] (4) The fluid delivery system of the present invention may be configured to transition to operation in the tank accumulation mode while operating in the pump supply mode on the condition that the remaining amount of fluid in the storage section of the pump falls below a predetermined value, transition to operation in the tank supply mode while operating in the tank accumulation mode on the condition that either or both of the remaining amount of fluid in the buffer tank exceeds a predetermined value and the remaining amount of fluid in the storage section reaches a lower limit, transition to operation in the combined supply mode while operating in the tank supply mode on the condition that the remaining amount of fluid in the buffer tank falls below a predetermined value, and transition to operation in the pump supply mode while operating in the combined supply mode on the condition that the remaining amount of fluid in the buffer tank reaches a lower limit.

[0014] The fluid dispensing system of the present invention can switch to a tank accumulation mode while operating in a pump supply mode if the remaining amount of fluid in the pump's reservoir falls below a predetermined value. Therefore, the fluid dispensing system of the present invention can switch its operating mode to a tank accumulation mode and accumulate fluid in a buffer tank in preparation for the situation where the pump is no longer able to supply fluid to the dispensing device. Furthermore, the fluid dispensing system of the present invention can switch to a tank supply mode while operating in the tank accumulation mode if either or both of the following conditions are satisfied: the amount of fluid accumulated in the buffer tank exceeds a predetermined value; or the remaining amount of fluid in the reservoir reaches a lower limit. This allows the fluid dispensing system of the present invention to supply fluid from the buffer tank to the dispensing device instead of the pump. Furthermore, the fluid dispensing system of the present invention can switch to a combined supply mode while operating in the tank supply mode if the remaining amount of fluid in the buffer tank falls below a predetermined value. This allows the fluid dispensing system of the present invention to compensate for the fluid dispensing capacity of the buffer tank by operating the pump, thereby ensuring a stable and continuous supply of fluid to the dispensing device. Furthermore, the fluid dispensing system of the present invention can switch to operation in the pump supply mode when the remaining amount of fluid in the buffer tank reaches a lower limit while operating in the combined supply mode, thereby continuing to stably supply the fluid to the dispensing device. By sequentially switching between each operation mode in this manner, the fluid dispensing system of the present invention can utilize the pump and the buffer tank in a complementary manner to supply the fluid to the dispensing device, thereby achieving a stable supply of the fluid to the dispensing device.

[0015] (5) The fluid discharge system of the present invention may be provided with a remaining quantity grasping unit in the supply path that grasps the remaining quantity of fluid in the discharge device, and the operation of the pump and the buffer tank may be controlled based on the measurement value of the pressure detection unit in the tank accumulation mode, the pump supply mode, the tank supply mode, and the combined supply mode.

[0016] With this configuration, the pump and buffer tank in each operating mode can be controlled to operate under optimal conditions for a stable supply of fluid, based on the remaining amount of fluid in the discharge device as determined by the remaining amount determination unit.

[0017] (6) In the fluid dispensing system of the present invention, it is preferable that the dispensing device continues to dispense the fluid during operation in the tank accumulation mode.

[0018] With this configuration, the discharge of the fluid from the discharge device and the accumulation of the fluid in the buffer tank can proceed simultaneously, and 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 in order to allow the fluid to accumulate in the buffer tank.

[0019] (7) In the fluid dispensing system of the present invention, in the tank accumulation mode, the buffer tank may intermittently perform a suction operation while the pump continues to supply fluid.

[0020] With this configuration, it is possible to minimize the decrease in the amount of fluid remaining in the discharge device due to the suction operation in the buffer tank, thereby further stabilizing the supply of fluid to the discharge device.

[0021] (8) The fluid dispensing system of the present invention may be provided with a remaining amount grasping unit in the supply path that grasps the remaining amount of fluid in the dispensing device, and the buffer tank may perform a suction operation on the condition that the measurement value of the remaining amount grasping unit exceeds a predetermined upper limit value.

[0022] With this configuration, problems such as unstable supply pressure, discharge pressure, and discharge amount of the fluid in the discharge device due to the decrease in the remaining amount of the fluid in the discharge device caused by the suction operation in the buffer tank can be minimized, thereby further stabilizing the supply state of the fluid to the discharge device.

[0023] (9) In the fluid dispensing system of the present invention, in the combined supply mode, the fluid in the buffer tank may be consumed preferentially over the fluid stored in the storage section.

[0024] With this configuration, the fluid stored in the buffer tank can be used preferentially in the combined supply mode, thereby minimizing concerns about deterioration of the fluid due to the fluid being stored in the buffer tank.

[0025] (9) The fluid discharge system of the present invention is preferably characterized in that the buffer tank is equipped with a position variable member whose position varies within a predetermined range depending on the amount of fluid remaining, and a detection device that detects the position of the position variable member, and the amount of fluid remaining 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.

[0026] With this configuration, the remaining amount of fluid in the buffer tank can be continuously detected. Also, with 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, thereby controlling the operation of the fluid dispensing system. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide a fluid dispensing system that can stably supply a fluid to a dispensing device while suppressing increases in installation space and costs. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram showing an example of a fluid discharge system of the present invention. [Figure 2] 2 is a cross-sectional view showing an example of a discharge device used in the fluid discharge system of FIG. 1. FIG. [Figure 3] 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 decompressed state. FIG. [Figure 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 holding state. FIG. [Figure 6] 2A and 2B are explanatory diagrams illustrating the operating states of the components 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] 2 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 showing the fluid delivery system of FIG. 1 operating in a pump supply mode. [Figure 9] 1. (a) and (b) are explanatory diagrams illustrating the operating states of each part 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] 2 is a timing chart when the fluid dispensing system of FIG. 1 operates in a tank accumulation mode. [Figure 11] 2 is a flowchart showing the operation of the fluid dispensing system of FIG. 1 in a tank accumulation mode. [Figure 12] 1. (a) and (b) are explanatory diagrams illustrating the operating states of the components of the fluid dispensing 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] 2 is a timing chart when the fluid dispensing system of FIG. 1 operates in a tank supply mode. [Figure 14]2 is a flowchart showing the operation of the fluid dispensing system of FIG. 1 in a tank supply mode. [Figure 15] 1. (a) and (b) are explanatory diagrams illustrating the operating states of each part 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 chart when the fluid dispensing system of FIG. 1 operates in a multiple supply 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 flowchart of the fluid dispensing system of FIG. 1 operating in a first operating mode. [Figure 19] 4 is a timing chart when the fluid dispensing system of FIG. 1 operates in a first operation mode. [Figure 20] 2 is a flowchart illustrating the fluid dispensing system of FIG. 1 operating in a second operating mode. [Figure 21] 1. FIG. 4 is a cross-sectional view of a modified example of the buffer tank used in the fluid dispensing system of FIG. [Figure 22] 1. FIG. 4 is a cross-sectional view of a main part of a modified example of the buffer tank used in the fluid dispensing system of FIG. [Figure 23] 1. FIG. 4 is a cross-sectional view of a main part of a modified example of the buffer tank used in the fluid dispensing system of FIG. [Figure 24] FIG. 10 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. [Figure 25] 10A and 10B are images showing an example of a user interface that indicates the amount of fluid stored in the buffer tank and the operating mode of the fluid dispensing system. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, a fluid dispensing system 10 according to one embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the configuration of the fluid dispensing system 10 will be described first, and then the operation of the fluid dispensing system 10 will be described.

[0030] <Configuration of 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 by a supply path 40. The fluid discharge system 10 is configured by providing a buffer tank 50 midway through the supply path 40. The fluid discharge system 10 also includes a remaining amount determining unit 90 for determining 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.

[0031] Pump 20 is a device for pumping up and pressure-feeding a fluid from storage section 22 where the fluid is stored. Pump 20 is connected to supply path 40 via a pipe. Therefore, the fluid pumped up from the storage section by pump 20 can be pressure-feed to discharge device 30 via supply path 40.

[0032] The discharge device 30 is configured as a rotary positive displacement pump. In this embodiment, the discharge device 30 is configured as a so-called uniaxial eccentric screw pump. As shown in FIG. 2 , the discharge device 30 is configured such that a rotor 102, a stator 104, a power transmission mechanism 106, etc. are housed inside a casing 100. The casing 100 is a cylindrical member made of metal, 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 an intermediate portion 114 located in the longitudinal intermediate portion of the casing 100.

[0033] The first opening 110 and the second opening 112 are portions that function as a suction port and a discharge port, respectively, of the uniaxial 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 as a suction port by rotating the rotor 102 in the forward direction. In addition, the first opening 110 can function as a suction port and the second opening 112 as a discharge port by rotating the rotor 102 in the reverse direction.

[0034] The stator 104 is a member having a substantially cylindrical external shape made of an elastic body such as rubber, or a resin. The inner peripheral wall 116 of the stator 104 has an n-thread single-stage or multi-stage female thread shape. In this embodiment, the stator 104 has a two-thread multi-stage female thread shape. Furthermore, the through-hole 118 of the stator 104 is formed so that its cross-sectional shape (opening shape) is substantially oval when viewed in cross section at any position in the longitudinal direction of the stator 104.

[0035] The rotor 102 is a metal shaft body having an n-1 start single-stage or multi-stage male screw thread. In this embodiment, the rotor 102 has a single-start eccentric male screw thread. The rotor 102 is formed so that its 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 stator 104 described above, and is capable of free eccentric rotation within the through-hole 118.

[0036] 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 spirally in the longitudinal direction of the stator 104 and the rotor 102.

[0037] When the rotor 102 is rotated within the through-hole 118 of the stator 104, the fluid transport path 122 moves in the longitudinal direction of the stator 104 while rotating within the stator 104. Therefore, when the rotor 102 is rotated, a fluid is sucked into the fluid transport path 122 from one end side of the stator 104, and the fluid is transported toward the other end side of the stator 104 while being confined within the fluid transport path 122, and can be discharged from the other end side of the stator 104. Specifically, when the rotor 102 is rotated in the forward direction, an operation of sucking a fluid through the second opening 112 and discharging it from the first opening 110 (discharge operation) can be performed. Furthermore, when the rotor 102 is rotated in the reverse direction, an operation of sucking a fluid in the opposite direction to the discharge operation, i.e., from the first opening 110 side toward the second opening 112 side (pull-back operation) can be performed.

[0038] The power transmission mechanism 106 transmits power from the driver 124 to the rotor 102. The power transmission mechanism 106 includes a power transmission unit 126 and an eccentric rotation unit 128. The power transmission unit 126 is provided at one longitudinal end of the casing 100. The eccentric rotation unit 128 is provided in the intermediate portion 114. The eccentric rotation unit 128 connects the power transmission unit 126 and the rotor 102 so that power can be transmitted between them. The eccentric rotation unit 128 includes a connecting shaft 130 formed of a conventionally known coupling rod, screw rod, or the like. Therefore, the eccentric rotation unit 128 can transmit rotational power generated by operating the driver 124 to the rotor 102, causing the rotor 102 to rotate eccentrically.

[0039] 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 midway along the supply path 40. Specifically, the supply path 40 has a primary-side supply path 42 that connects 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-side supply path 44 that connects 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.

[0040] A sensor 92 constituting a remaining amount detecting unit 90, which will be described in detail later, and a valve 48 are provided midway through the supply path 40. The sensor 92 may 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.

[0041] The buffer tank 50 is disposed midway along the above-described supply path 40. The buffer tank 50 is capable of suctioning and discharging fluid. The buffer tank 50 can accumulate fluid inside by suctioning the fluid. Furthermore, when the pump 20 stops supplying the fluid, the buffer tank 50 discharges the fluid accumulated inside, thereby enabling the continuous supply of fluid to the discharge device 30. The operation of the buffer tank 50 is controlled by the control device 200 in accordance with the remaining amount of 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 fluctuation mechanism 54.

[0042] The tank portion 52 is capable of causing a fluid to flow in and out of the supply path 40. In this embodiment, the tank portion 52 is provided with a connection portion 56 at one end side of a tubular (in this embodiment, substantially cylindrical) tank main body portion 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 portion 52a.

[0043] The connection portion 56 is provided at one axial end of the tank main body 52a that constitutes the tank portion 52. The connection portion 56 is a portion that is connected to the supply path 40. The connection portion 56 has a flow path 56a that extends in a direction (in the radial direction in this embodiment) that intersects the axial direction of the tank portion 52. The connection portion 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 portion 52 and are connectable to the piping that constitutes the supply path 40. The connection portion 56 also has a communication hole 56d at a radially intermediate portion of the tank portion 52. The tank portion 52 is in communication with the flow path 56a and the internal space (communication space 58) of the tank main body 52a via the communication hole 56d.

[0044] 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 connection part 56 described above. 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.

[0045] The non-communicating space 60 is a space that does not communicate with the supply path 40. The non-communicating space 60 is a space that is adjacent to the communicating space 58 in the axial direction of the tank portion 52, on the opposite side of the connecting portion 56 from 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 of the non-communicating space 60. As a result, the non-communicating space 60 communicates with a casing 68 that forms a drive portion 64 of the volume fluctuation mechanism 54.

[0046] 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 drive portion 64, and the drive portion 64 can move the piston portion 62 in the axial direction of the tank portion 52 inside the tank portion 52. Therefore, the volume variation mechanism 54 can vary 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 with the drive portion 64.

[0047] The piston portion 62 separates the interior 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 that constitutes 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.

[0048] The drive unit 64 moves the piston unit 62 in the axial direction inside the tank main body 52a. The drive unit 64 includes a rod unit 66, a casing 68, a partition wall 70, and an air intake / exhaust device 72. The rod unit 66 is inserted into the tank main body 52a from the non-communicating space 60 side. The rod unit 66 is disposed so as to extend in the axial direction of the tank main body 52a. The piston unit 62 is connected to one end of the rod unit 66. The connection between the rod unit 66 and the piston unit 62 may be achieved by, for example, providing a female thread on one end and a male thread on the other end and threading them together, or by using a fastener such as a screw to integrate the two. Furthermore, instead of fixing the piston unit 62 and the rod unit 66 to each other as in this embodiment, the piston unit 62 and the rod unit 66 may be connected by contacting their tip ends. Furthermore, the tip end 66a of the rod unit 66 may be detachable from the shaft 66b of the rod unit 66. If a plurality of tip portions 66a with different lengths are prepared, the length of the rod portion 66 can be changed on the tip portion 66a side, and the stroke length of the piston portion 62 can be adjusted.

[0049] A partition wall 70 is connected to the other end of the rod portion 66. The partition wall 70 is integrated with the rod portion 66. In this embodiment, the other end of the rod portion 66 is axial, but the length may be adjustable in the same way as the tip portion 66a.

[0050] The casing 68 is a cylindrical member having a hollow interior 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.

[0051] The partition wall 70 separates the interior 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 sealing member such as an O-ring. The other end of the rod portion 66 (the side opposite the connection end of the piston portion 62) is connected to the surface of the partition wall 70 on the second space 70b side. The partition wall 70, together with the rod portion 66, is reciprocable in the axial direction of the casing 68 while maintaining its outer peripheral surface in contact with the inner peripheral surface of the casing 68. The partition wall 70 can reciprocate in the axial direction within the casing 68 by introducing and discharging gas via the first casing connection port 68a and the second casing connection port 68b, thereby changing the pressure balance between the first space 70a and the second space 70b.

[0052] An intake and exhaust device 72 is connected to the first casing connection port 68a by piping. The intake and exhaust device 72 not only introduces and exhausts gas (air in this embodiment) to and from the casing 68, but 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 a first piping system 74 that connects a gas supply source 72a and the first casing connection port 68a of the casing 68.

[0053] The supply source 72a is capable of pressurizing gas toward the casing 68. The supply source 72a can be configured with, 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 any suitable switching type, such as a three-position closed center type or a three-position pressure center type, but in this embodiment, a solenoid valve employing a three-position exhaust center switching type is used. Using a three-position exhaust center type solenoid valve 72b as in this embodiment ensures sufficient responsiveness even when the solenoid valve 72b and the casing 68 are distant from each other.

[0054] The solenoid valve 72b has an intake port PI connected to a supply source 72a. Two output ports A and B of the solenoid valve 72b are connected to a pilot check valve 72c via pipes. The solenoid valve 72b also has 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 its valve position. Specifically, as shown in FIG. 3, in the first state, the intake port PI is connected to the output port B, and the exhaust port EA is connected to the output port A. As shown in FIG. 4, in the second state, the intake port PI is connected to the output port A, and the exhaust port EB is connected to the output port B. As shown in FIG. 5, in the third state, the output ports A and B are connected to the exhaust ports EA and EB, respectively.

[0055] 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 output ports A and B of the solenoid valve 72b, respectively. The connection port PC of the pilot check valve 72c is also connected by piping leading to the first casing connection port 68a. 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 prevents gas from flowing in the opposite direction, from the connection port PC to the connection port PB. When a pressure equal to or greater than a predetermined value is applied to the connection port PA, the pilot check valve 72c is released from its function as a check valve, allowing gas to flow from the connection port PC to the connection port PB.

[0056] 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 is applied to the connection port PB, gas flows from the connection port PB to the connection port PC, allowing gas to be introduced into the casing 68 through the first casing connection port 68a. When the solenoid valve 72b is in the second state, pressure equal to or greater than a predetermined value is applied to the connection port PA, preventing the pilot check valve 72c from functioning as a check valve. The connection port PA is open to the atmosphere through the exhaust port EB of the solenoid valve 72b. Therefore, when the solenoid valve 72b is in the second state, gas can be exhausted 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 where gas does not enter or leave.

[0057] The first speed controller 72d is provided in the pipeline 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 release valve. The first speed controller 72d is also capable of meter-out control.

[0058] Meanwhile, 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.

[0059] By utilizing the above-described configuration, the buffer tank 50 can achieve three states: a pressurized state, a depressurized state, and a holding state. Each of these states can be achieved by controlling the movement of the piston 62 inside the tank 52 using the drive unit 64 constituting the volume fluctuation mechanism 54.

[0060] Specifically, the pressurized state is a state in which a pressurizing force is exerted on the fluid. The pressurized state can be achieved by using the volume fluctuation mechanism 54 to reduce the volume of the communication space 58, which is in communication with the supply path 40 within the tank portion 52. More specifically, to pressurize the buffer tank 50, as shown in FIG. 3, the solenoid valve 72b constituting the drive unit 64 is set to the first state, and gas is supplied to the solenoid valve 72b from the supply source 72a. This results in a state in which no pressure acts on the connection port PA of the pilot check valve 72c, but pressure acts on the connection port PB. Gas flows from the connection port PB to the connection port PC and is introduced into the first space 70a through the first casing connection port 68a provided in the casing 68 of the drive unit 64. Accordingly, the partition wall 70 moves in a direction that expands the first space 70a within the casing 68. This increases the pressure acting on the non-communicating space 60 side of the piston portion 62, which is connected to the partition wall 70 via the rod portion 66. Accordingly, the piston portion 62 moves in a direction that reduces the volume of the communication space 58. In this way, the buffer tank 50 is brought into a pressurized state in which a pressurizing force is exerted on the fluid.

[0061] The reduced-pressure state is a state in which a decompression force is exerted on the fluid. The reduced-pressure state can be achieved by increasing the volume of the communication space 58, which is connected to the supply path 40 within the tank portion 52, using the volume fluctuation mechanism 54. To put the buffer tank 50 into a reduced-pressure state, as shown in FIG. 4, the solenoid valve 72b constituting the drive unit 64 is set to the second state, and gas is supplied to the solenoid valve 72b from the supply source 72a. This causes a pressure equal to or greater than a predetermined value to act on the connection port PA of the pilot check valve 72c, preventing the pilot check valve 72c from functioning as a check valve. Furthermore, 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 set to the second state, gas is discharged from the first casing connection port 68a of the casing 68. Accordingly, within the casing 68, the partition wall 70 moves in a direction that increases the size of the second space 70b. As a result, the pressure acting on the piston 62, which is connected to the partition wall 70 via the rod 66, on the non-communicating space 60 side decreases. This causes the piston 62 to move in a direction that increases the volume of the communicating space 58. In this way, the buffer tank 50 enters a decompressed state in which a decompressing force acts on the fluid.

[0062] The holding state is a state in which neither pressurizing nor depressurizing force is applied to the fluid. The holding state can be achieved by stopping the volume change mechanism 54 from increasing or decreasing the volume of the communication space 58. More specifically, to set the buffer tank 50 to the holding state, as shown in FIG. 5 , the solenoid valve 72b constituting the drive unit 64 is set to the third state. This prevents pressure from acting on either the connection port PA or PB provided in the pilot check valve 72c, causing the pilot check valve 72c to function as a check valve. Therefore, when the solenoid valve 72b is set to the third state, gas cannot flow in or out of the casing 68. Therefore, the partition wall 70 inside the casing 68 is in a stopped state. Accordingly, there is no fluctuation in pressure acting on the piston 62 connected to the partition wall 70 via the rod 66, and no fluctuation in the volume of the communication space 58. In this way, the buffer tank 50 is set to the holding state in which neither pressurizing nor depressurizing force is applied to the fluid.

[0063] 1, a remaining amount determining unit 90 is provided downstream of the buffer tank 50 in the direction of flow of the fluid toward the discharging device 30. The remaining amount determining unit 90 is for determining the remaining amount of fluid in the discharging device 30. The remaining amount determining unit 90 may, for example, directly measure the remaining amount of fluid in the discharging device 30, or may indirectly determine the remaining amount of fluid in the discharging device 30 from the supply state of the fluid to the discharging device 30 or the discharge state of the fluid from the discharging device 30. Specifically, the remaining amount determining unit 90 may indirectly determine the remaining amount of fluid in the discharging device 30 from measurements related to the supply state of the fluid, such as the supply pressure of the fluid to the discharging device 30 or the flow rate of the fluid to the discharging device 30.

[0064] 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 flowing material, and a processing unit 94 for performing a process for grasping the remaining amount of the flowing material in the discharge device 30 based on the measurement value 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 flowing material to the discharge device 30 (hereinafter, also referred to as "supply pressure P") is adopted as the sensor 92. Further, the function as the processing unit 94 is borne by the 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 flowing material 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 flowing material in the discharge device 30 is within the appropriate range.

[0065] The control device 200 is for controlling the operation of the flowing material 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.

[0066] ≪Regarding the operation of the flowing material discharge system 10≫ The flowing material discharge system 10 can be operated in four operation modes under the control of the control device 200. Specifically, the flowing material discharge system 10 can be operated in four operation modes including (1) pump supply mode, (2) tank accumulation mode, (3) tank supply mode, and (4) composite supply mode. Further, the flowing material discharge system 10 can stably discharge the flowing material in the discharge device 30 by sequentially performing the operations in the four operation modes. Hereinafter, regarding the operation of the flowing material 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 flowing material discharge system 10 realized by sequentially performing the operations in each operation mode will be described.

[0067] (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 start and stop depending on the remaining amount of fluid in the discharge device 30 as determined by the remaining amount determining unit 90.

[0068] In this embodiment, the control device 200 determines 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 in accordance with 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 when the supply pressure P is equal to or greater than a predetermined upper limit pressure PH, determining that the supply of fluid to the discharge device 30 is unnecessary. On the other hand, when the supply pressure P is equal to or less than a predetermined lower limit pressure PL, the control device 200 operates the pump 20, determining 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.

[0069] (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.

[0070] (Step 1-2) In step 1-2, the control device 200 checks whether the remaining amount of fluid in the reservoir 22 of the pump 20 has decreased to the lower limit of the reservoir 22. If the remaining amount of fluid in the reservoir 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 the amount of fluid in the reservoir 22 exceeds the lower limit, the control device 200 advances the control flow to step 1-3.

[0071] (Steps 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 determination 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.

[0072] (Steps 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.

[0073] (Steps 1-5) In step 1-5, the control device 200 checks whether the remaining amount of fluid in the reservoir 22 of the pump 20 has reached a lower limit. If the remaining amount of fluid in the reservoir 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.

[0074] (Steps 1-6) In step 1-5 described above, if the remaining amount of fluid in reservoir 22 has reached the lower limit, further operation of pump 20 will not allow the fluid to be supplied to discharge device 30. Therefore, in step 1-6, control device 200 ends the series of control flows.

[0075] (Steps 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.

[0076] (Steps 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.

[0077] (Steps 1-9) In step 1-9, the control device 200 checks the remaining amount of fluid in the reservoir 22 of the pump 20. If the remaining amount of fluid has not reached the lower limit of the reservoir 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 reservoir 22, the pump 20 cannot supply any more fluid to the discharge device 30, and the control flow is terminated.

[0078] (2) Tank accumulation mode Next, the tank accumulation mode will be described in detail. The tank accumulation mode is an operating mode in which the fluid is accumulated (charged) in the buffer tank 50 while continuing to supply fluid from the pump 20 in preparation for the tank supply mode, which will be described in detail later. The tank accumulation mode is an operating mode in which the fluid is accumulated inside the buffer tank 50 (communicating 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. Furthermore, the tank accumulation mode is an operating mode in which the discharge device 30 can continue to discharge the fluid even while the fluid is accumulating in the buffer tank.

[0079] 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 and stop depending on the remaining amount of fluid in the discharge device 30 as determined by the remaining amount determining unit 90.

[0080] 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 determining unit 90, as shown in the operation explanatory diagram of FIG. 9 and the timing chart of FIG. 10. The control device 200 determines the remaining amount of 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 in accordance with 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 fluid is stored in the discharge device 30, and the buffer tank 50 is depressurized to accumulate the fluid in the communication space 58 of the tank unit 52. More specifically, as shown in FIG. 9(a), the control device 200 opens the valve 48 to stop the pump 20 and depressurize the buffer tank 50. This causes the fluid to accumulate in the buffer tank 50. The operating conditions, such as the timing and duration for decompressing the buffer tank 50, may be determined taking into account undershoot of the supply pressure P, for example, by limiting the time to a predetermined period after the supply pressure P reaches the upper limit pressure PH.

[0081] On the other hand, when the supply pressure P is lower than a predetermined lower limit pressure PL (first lower limit), the remaining amount of fluid in the discharge device 30 is below an appropriate value, so the buffer tank 50 is set to 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 opens the valve 48 to operate the pump 20 and sets the buffer tank 50 to a holding state. As a result, the control device 200 supplies the fluid pumped by the pump 20 to the discharge device 30.

[0082] By performing this control in the tank accumulation mode, the control device 200 accumulates the fluid in the buffer tank 50 when the supply pressure P is sufficiently high (when there is a sufficient amount 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 taking advantage of the fact that the buffer tank 50 can achieve 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.

[0083] (Step 2-1) In step 2-1, 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. 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.

[0084] (Step 2-2) In step 2-2, the control device 200 checks whether the remaining amount of fluid in the reservoir 22 of the pump 20 has decreased to the lower limit of the reservoir 22. If the remaining amount of fluid in the reservoir 22 is at the lower limit, the control flow in Fig. 11 is terminated. On the other hand, if the remaining amount of fluid in the reservoir 22 exceeds the lower limit, the control device 200 advances the control flow to step 2-3.

[0085] (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 determination 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. Therefore, in this case, the control device 200 advances the control flow to step 2-4.

[0086] (Steps 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.

[0087] (Steps 2-5) In step 2-5, the control device 200 checks whether the remaining amount of fluid in the reservoir 22 of the pump 20 has reached a lower limit. If the remaining amount of fluid in the reservoir 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 fluid has not reached the lower limit, the control device 200 advances the control flow to step 2-7.

[0088] (Steps 2-6) When the control flow has shifted to step 2-6, there is not enough fluid remaining in the reservoir 22. Therefore, the control device 200 stops the pump 20. Then, the control flow ends.

[0089] (Steps 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.

[0090] (Steps 2-8) In step 2-8, the control device 200 stops the pump 20. Thereafter, the control device 200 advances the control flow to step 2-9.

[0091] (Steps 2-9) In step 2-9, the control device 200 places the buffer tank 50 in a depressurized state. Specifically, the control device 200 controls the operation of the solenoid valve 72b, which constitutes the volume fluctuation mechanism 54 of the buffer tank 50, so that it is in the second state. The supply source 72a, such as an air compressor, supplies gas to the solenoid valve 72b. 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 via the connection port PA of the pilot check valve 72c and the exhaust port EB of the solenoid valve 72b. Accordingly, the partition wall 70 begins to move inside the casing 68, and the piston portion 62 moves in a direction that increases the volume of the communication space 58. In this way, the buffer tank 50 enters a depressurized state in which a decompression force acts on the fluid. When the communication space 58 of the buffer tank 50 enters a depressurized state, the fluid begins to flow from the supply path 40 into the communication space 58 and accumulates therein. When the buffer tank 50 is depressurized in step 2-9, the control device 200 advances the control flow to step 2-10.

[0092] (Steps 2-10) In step 2-10, the control device 200 manages the amount of accumulated fluid in the buffer tank 50 since the start of accumulation of fluid in the buffer tank 50 in step 2-9 so that the amount of accumulated fluid falls within a predetermined range. The amount of accumulated fluid in the buffer tank 50 can be determined directly or indirectly, for example, by directly measuring and deriving the amount using a remaining amount sensor, by detecting and subtracting the amount of fluid flowing into and out of the buffer tank 50, or by indirectly determining the amount of fluid flowing in and out of the buffer tank 50. In this embodiment, the control device 200 manages the amount of accumulated fluid since the start of accumulation of fluid in the buffer tank 50 in step 2-9 based on the time elapsed since the buffer tank 50 was depressurized in step 2-9. In step 2-10, the control device 200 checks whether the elapsed time Tx since the start of accumulation of 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.

[0093] (Step 2-11) In step 2-11, the control device 200 switches the buffer tank 50 to the holding state, so that neither pressurizing nor depressurizing force is applied to the fluid. Specifically, the control device 200 switches the solenoid valve 72b provided in the drive unit 64 of the buffer tank 50 to the third state. This prevents pressure from acting on either of the connection ports PA or PB provided in the pilot check valve 72c, causing the pilot check valve 72c to function as a check valve, stopping the flow of gas into and out of the casing 68 of the drive unit 64. This stops the partition wall 70 disposed inside the casing 68, and stops the piston unit 62 connected to the partition wall 70 within the tank unit 52. In this way, the control device 200 switches the buffer tank 50 to the holding state. After that, the control device 200 advances the control flow to step 2-12.

[0094] (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 can be determined based on the output values ​​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, for example. Alternatively, the amount of fluid stored in the buffer tank 50 can be detected or derived and determined based on the inflow and outflow amounts. If, in step 2-12, 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 allow further accumulation of 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 the control flow.

[0095] (3) Tank supply mode Next, the tank supply mode will be described in detail. The tank supply mode is an operation mode in which fluid is supplied from the buffer tank 50 to the discharge device 30 while the pump 20 is stopped. Operation in the tank supply mode is an operation mode for discharging fluid from the buffer tank 50 to the supply path 40 when the pump 20 is stopped, for example, to replace the reservoir 22 in the pump 20 or to replenish the reservoir 22 with fluid, thereby enabling the continuous supply of fluid to the discharge device 30.

[0096] 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 determining unit 90. Specifically, in the tank supply mode, when supplying fluid to the discharge device 30, the operation of the buffer tank 50 is controlled so that the fluid is discharged when the measurement value of the remaining amount determining unit 90 falls below a predetermined lower limit (second lower limit). More specifically, when 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. This allows the fluid to be supplied from the buffer tank 50 to the discharge device 30 without the pump 20 pumping the fluid. Note that the lower limit pressure PL, which is the second lower limit, is set to the same value (pressure) as the first lower limit in the tank accumulation mode described above, but they may be different values ​​(pressures).

[0097] On the other hand, in the tank supply mode, the buffer tank 50 is controlled to stop discharging the fluid when the measurement value of the remaining amount grasping unit 90 exceeds a predetermined upper limit (second upper limit). More specifically, in the tank supply mode, when the supply pressure P detected by the sensor 92 exceeds a predetermined upper limit pressure PH, the pump 20 is stopped and the valve 48 is closed, and the buffer tank 50 is placed in a holding state. This prevents the fluid from being excessively supplied to the discharge device 30 that is sufficiently filled with the fluid. Note that the upper limit pressure PH, which is the second upper limit, is set to the same value (pressure) as the first upper limit value in the tank accumulation mode described above, but the two values ​​(pressures) may be different.

[0098] 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.

[0099] (Step 3-1) In step 3-1, the control device 200 checks the fluid storage state in the buffer tank 50. If the amount of fluid stored in the buffer tank 50 is at its lower limit, there is a concern that the buffer tank 50 may be unable to supply fluid, and therefore the control device 200 completes the control flow. Here, in this step and the following steps, "when the amount of fluid stored in the buffer tank 50 is at its lower limit" may refer to a state in which the amount of fluid has decreased to a level in which the fluid cannot be supplied. However, in this embodiment, the control device 200 defines a state just before the level in which the fluid cannot be supplied (when a small amount of fluid remains) as a state in which the amount of fluid stored is at its lower limit, and performs operational control. On the other hand, if 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.

[0100] (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 determining unit 90 is equal to or less 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, a sufficient amount of fluid remains 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 less 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.

[0101] (Step 3-3) In step 3-3, the control device 200 pressurizes the buffer tank 50. This causes the control device 200 to apply a pressurizing force to the fluid in the buffer tank 50, discharging the fluid from the buffer tank 50 toward the discharge device 30 via 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 62 in a direction that decreases the volume of the communication space 58 communicating with the supply path 40. More specifically, the control device 200 sets the solenoid valve 72b provided in the drive unit 64 to the first state, and supplies gas to the solenoid valve 72b from the supply source 72a. This causes gas compressed from the supply source 72a, such as an air compressor, to pass through the solenoid valve 72b, the pilot check valve 72c, and the first casing connection port 68a into the first space 70a of the casing 68. 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 way, the control device 200 pressurizes the buffer tank 50. When the buffer tank 50 is pressurized, the fluid stored in the communication space 58 is discharged toward the discharge device 30 via the supply path 40.

[0102] (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.

[0103] (Steps 3-5) In step 3-5, the control device 200 stops the discharge of the fluid from the buffer tank 50. Specifically, the control device 200 places the buffer tank 50 in a holding state, similar to step 2-11 described above. Thereafter, the control device 200 completes the series of control flows.

[0104] (Steps 3-6) In step 3-6, the control device 200 checks whether the discharge device 30 is sufficiently filled with fluid. Specifically, the control device 200 checks whether the supply pressure P has reached a predetermined upper limit pressure PH (second upper limit value). 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.

[0105] (Steps 3-7) In step 3-7, the control device 200 sets the buffer tank 50 to the holding state in the same manner as in steps 2-11 and 3-5 described above. Thereafter, the control device 200 advances the control flow to step 3-8.

[0106] (Steps 3-8) In step 3-8, the control device 200 checks the storage state of the fluid 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, further operation in the tank supply mode is not possible, and the control flow is terminated.

[0107] (4) Composite supply mode Next, the combined supply mode will be described in detail. The combined supply mode is an operating mode in which fluid is supplied to the discharge device 30 from both the pump 20 and the buffer tank 50. Operation in the combined supply mode is performed, for example, at the end of the above-mentioned tank supply mode when it is assumed that the remaining amount of fluid in the tank unit 52 is running low, to supplement the supply of fluid from the buffer tank 50 to the discharge device 30 with the supply of fluid from the pump 20. Operation in the combined supply mode when it is assumed that the remaining amount of fluid in the tank unit 52 is running low can both stabilize the supply pressure of fluid to the discharge device 30 and use up the fluid accumulated in the buffer tank 50.

[0108] That is, in the tank supply mode, as the amount of fluid remaining in the buffer tank 50 decreases, the distance between the bottom surface of the tank main body 52a and the piston 62 becomes narrower, and pressure loss increases. As a result, the flow rate of the fluid discharged from the buffer tank 50 toward the discharge device 30 decreases. If the flow rate of the fluid from the buffer tank 50 to the discharge device 30 falls below the discharge rate of the fluid from the discharge device 30, a shortage of fluid supply occurs. Therefore, when the amount of fluid remaining in the buffer tank 50 falls below a certain level, the operating mode is switched to the combined supply mode, and the pump 20 is operated to supply the fluid in addition to the buffer tank 50. This makes it possible to use up the fluid stored in the buffer tank 50 while stabilizing the supply pressure of the fluid to the discharge device 30.

[0109] 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 determining 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 to the discharge device 30, provided that the measurement value of the remaining amount determining 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 open, provided that the supply pressure P detected by the sensor 92 falls below a predetermined lower limit pressure PL. In this way, 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 to be 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 ensure that the fluid in the buffer tank 50 is used up 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.

[0110] On the other hand, in the combined supply mode, the pump 20 and the buffer tank 50 are controlled to stop discharging the fluid when the measurement value of the remaining amount grasping unit 90 exceeds a predetermined upper limit. More specifically, in the combined supply mode, the pump 20 is stopped and the buffer tank 50 is set to a holding state when 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.

[0111] 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 dispensing system 10 in the combined supply mode will be described in further detail with reference to the flowchart in Fig. 17.

[0112] (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.

[0113] (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 greater than a predetermined time T1. Here, the predetermined time T1 is the time measured to determine when to terminate the composite supply mode. By using the predetermined time T1 as a determination condition in step 4-2, it is possible to provide limit switches, etc., only at a position slightly before the lower limit of the buffer tank 50, instead of providing them at two locations: one just before the lower limit and the other just before the lower limit. Specifically, by defining the predetermined time T1 based on the time it is expected that the buffer tank 50 will become empty if operation continues after the remaining amount of fluid is detected by a sensor provided just before the lower limit of the buffer tank 50, the composite supply mode can be terminated at an appropriate timing. In this way, rather than providing limit switches or the like at two locations, one just before the lower limit of the buffer tank 50 and the other just below the lower limit, the composite supply mode is terminated using the predetermined time T1 as an indicator after the fluid is detected just before the lower limit of the buffer tank 50. This has the advantage of preventing the composite supply mode from never ending, even if the liquid hardens at the bottom of the buffer tank 50 and the piston does not fully descend. Here, if it is confirmed that the timer time Ty is equal to or greater than the predetermined time T1, the control device 200 terminates the control flow. On the other hand, if the timer time Ty is less than the predetermined time T1, the control device 200 advances the control flow to step 4-3.

[0114] (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.

[0115] (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 toward the discharge device 30. Thereafter, the control device 200 advances the control flow to step 4-5.

[0116] (Step 4-5) In step 4-5, the control device 200 checks the elapsed time 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 causes the control flow to wait 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.

[0117] (Steps 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 fluid to the discharge device 30 by the buffer tank 50, which has already started in step 4-4, continues. 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 starts, the control device 200 advances the control flow to step 4-7.

[0118] (Steps 4-7) In step 4-7, the control device 200 checks the timer time Ty that started counting 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.

[0119] (Steps 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 of 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.

[0120] (Steps 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.

[0121] (Steps 4-10) In step 4-10, similarly to step 4-8, the control device 200 stops the pump 20 and sets the buffer tank 50 to the holding state. Thereafter, the control device 200 advances the control flow to step 4-11.

[0122] (Steps 4-11) In step 4-11, the control device 200 checks the timer time Ty that started counting 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.

[0123] As described above, the fluid delivery system 10 can be operated in four operating modes: (1) pump supply mode, (2) tank accumulation mode, (3) tank supply mode, and (4) combined supply mode. Next, the overall operation of the fluid delivery system 10, which is realized by sequentially operating in these operating modes, will be described. The overall operation of the fluid delivery system 10 can be performed in either a first operating pattern in which the fluid is accumulated in the buffer tank 50 in an initial stage, or a second operating pattern in which the fluid is accumulated in the buffer tank 50 in an intermediate stage. Therefore, in the following explanation, the operation in the first operating pattern will be described first, and then the operation in the second operating pattern will be described.

[0124] [Overall Operation of the Fluid Dispensing System 10 in the First Operation Pattern] The first operating pattern is an operating pattern in which operation in each operating mode is repeated in the order of tank accumulation mode → pump supply mode → tank supply mode → combined supply mode. A mode switching condition for switching from operation in each operating mode to operation in the next operating mode is set for each operating mode. The control device 200 controls switching of the operating mode each time the mode switching condition is satisfied. When the fluid dispensing system 10 operates in the first operating pattern, the control device 200 controls the operation of the fluid dispensing system 10 in accordance with the flowchart shown in FIG. 18 and the timing chart shown in FIG. 19. The operation of the fluid dispensing system 10 in the first operating pattern will be described in more detail below with reference to FIGS. 18 and 19.

[0125] (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.

[0126] (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 storage mode. If it is determined that the amount of fluid stored in the buffer tank 50 has reached its upper limit, the control device 200 advances the control flow to step 5-3.

[0127] (Step 5-3) In step 5-3, the control device 200 starts operation in the pump supply mode in accordance with the control flow of Fig. 8. Thereafter, the control device 200 advances the control flow to step 5-4.

[0128] (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 determined 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.

[0129] (Step 5-5) In step 5-5, the control device 200 starts operation in the tank supply mode in accordance with the control flow of Fig. 14. Thereafter, the control device 200 advances the control flow to step 5-6.

[0130] (Steps 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 storage amount has decreased to a level at which the fluid can no longer be supplied, but in this embodiment, the control device 200 defines a stage just before the level at which the fluid can no longer 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 controls operation accordingly.

[0131] (Steps 5-7) In step 5-7, the control device 200 starts 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.

[0132] (Steps 5-8) In step 5-8, the control device 200 checks the timer time Ty in the fluid dispensing 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.

[0133] When the fluid discharge system 10 operates in the first operating pattern, the operation is controlled by the control device 200 in accordance with the above-described flow. As described above, the first operating pattern accumulates 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 operating pattern, the fluid accumulated in the buffer tank 50 can be supplied to the discharge device 30 not only when the fluid in the reservoir 22 of the pump 20 runs out, but also in cases where the pump 20 is unable to supply fluid due to an abnormality in the pump 20, for example.

[0134] [Overall operation of the fluid discharge system 10 according to the second operation pattern] Next, the overall operation of the fluid discharge system 10 in 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 → combined 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 in accordance with the flowchart shown in FIG. 20. Hereinafter, the operation of the fluid discharge system 10 in the second operation pattern will be described in more detail with reference to FIG. 20.

[0135] (Step 6-1) In step 6-1, the control device 200 starts operation in the pump supply mode in accordance with the control flow of Fig. 8. Thereafter, the control device 200 advances the control flow to step 6-2.

[0136] (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 determined 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.

[0137] (Step 6-3) In step 6-3, 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 6-4.

[0138] (Step 6-4) In step 6-4, the control device 200 checks the remaining amount of fluid in the reservoir 22 in the fluid discharge system 10, which is operating in the tank accumulation mode. If it is determined that the amount of accumulated fluid in the reservoir 22 has reached the lower limit, the control device 200 advances the control flow to step 6-5.

[0139] (Step 6-5) In step 6-5, the control device 200 starts operation in the tank supply mode in accordance with the control flow of Fig. 14. Thereafter, the control device 200 advances the control flow to step 6-6.

[0140] (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. 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 6-7. 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 storage amount has decreased to a level at which the fluid can no longer be supplied, but in this embodiment, the control device 200 defines a stage just before the level at which the fluid can no longer 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 controls operation accordingly.

[0141] (Steps 6-7) In step 6-7, the control device 200 starts 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.

[0142] (Steps 6-8) In step 6-8, the control device 200 checks the timer time Ty in the fluid dispensing 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 6-1.

[0143] When the fluid discharge system 10 operates in the second operating pattern, the control device 200 controls the operation in accordance with the above-described flow. As described above, the second operating pattern involves operating in the pump supply mode prior to operating in the tank accumulation mode, and then accumulating the fluid in the buffer tank 50 in the tank accumulation mode in the intermediate stage (step 6-3). In this way, when the fluid discharge system 10 operates in the second operating pattern, the fluid is accumulated in the buffer tank 50 just before the remaining amount of fluid in the storage section 22 of the pump 20 reaches its 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 operating pattern, the period during which the fluid is accumulated (remains) in the buffer tank 50 can be minimized.

[0144] As described above, the fluid discharge system 10 of this embodiment includes, in addition to the pump 20 and the discharge device 30, a buffer tank 50 disposed midway in the supply path 40 connecting the pump 20 and the discharge device 30. The fluid discharge system 10 is capable of realizing a pressure acting state in which the buffer tank 50 exerts pressure on the fluid. Furthermore, the fluid discharge system 10 is capable of realizing, as the pressure acting state, a pressurized state in which a pressurizing force is exerted on the fluid and a depressurized state in which a depressurized force is exerted on the fluid. Therefore, when the fluid discharge system 10 of this embodiment is in the pressurized state and pressure is exerted on the fluid toward the outside of the buffer tank 50, the fluid can be pressure-fed toward the discharge device 30. Therefore, the fluid discharge system 10 can suppress pressure fluctuations caused by switching the fluid supply source for the discharge device 30 from the pump 20 to the buffer tank 50.

[0145] Furthermore, when the buffer tank 50 is depressurized and pressure is applied to the fluid in a direction toward the inside of the buffer tank 50, the fluid can be smoothly sucked into the buffer tank 50. This allows the fluid dispensing system 10 to suck and store the fluid in the buffer tank 50 in preparation for supplying the fluid from the buffer tank 50 to the dispensing device 30. Therefore, the fluid dispensing system 10 can contribute to a stable supply of fluid to the dispensing device 30 by utilizing the fluid storage function of the buffer tank 50.

[0146] In the fluid discharge system 10 of this embodiment, the buffer tank 50 can achieve a holding state in which no pressure is applied to the fluid, in addition to the above-mentioned pressure-applied states (pressurized state, depressurized state). Therefore, in a state in which the discharge device 30 can discharge the fluid without using the buffer tank 50, such as when operating in the pump supply mode or when there is a sufficient amount of fluid remaining in the discharge device 30, or in a state in which it is not appropriate to continue accumulating liquid in the buffer tank 50 considering the amount of fluid remaining in the discharge device 30 when operating in the tank accumulation mode, fluctuations in the supply pressure of the fluid to the discharge device 30 and fluctuations in the discharge pressure of the fluid from the discharge device 30 due to the influence of the buffer tank 50 can be suppressed. Therefore, the fluid discharge system 10 of this embodiment can suppress fluctuations in the supply pressure of the fluid to the discharge device 30 and fluctuations in the discharge pressure of the discharge device 30 due to pressure acting on the fluid from the buffer tank 50.

[0147] 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 increases in installation space and costs compared to a configuration in which multiple pumps 20 are provided.

[0148] In this embodiment, the pressure acting state exerting pressure on the fluid in the buffer tank 50 is changed in three stages: 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 continuously.

[0149] Specifically, as described above, in the volume fluctuation mechanism 54, instead of providing the solenoid valve 72b, pilot check valve 72c, and 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. This configuration makes it possible to change the pressure acting on the fluid in multiple stages or continuously in a pressurized or depressurized state. Furthermore, this configuration also makes it possible to further optimize pressure control in the buffer tank 50 according to the operating state of the fluid discharge system 10, for example, by changing the pressure acting on the fluid from a strong pressurized state to a weak pressurized state instead of placing the buffer tank 50 in a depressurized state in the tank accumulation mode.

[0150] Furthermore, in the above-described fluid dispensing system 10, the buffer tank 50 includes a tank portion 52 and a volume fluctuation mechanism 54, and the volume fluctuation mechanism 54 controls the increase or 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 dispensing system 10 can control the operation of the buffer tank 50 by controlling the increase or decrease in the volume of the communication space 58.

[0151] As described above, in the fluid dispensing system 10, the volume fluctuation mechanism 54 includes a piston 62 that separates the interior of the tank 52 into a communicating space 58 and a non-communicating space 60 that is not connected to the supply channel 40, and a drive unit 64 that moves the piston 62. 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 62 using the drive unit 64. Therefore, the fluid dispensing system 10 can appropriately realize a pressurized state, a depressurized state, and a holding state by controlling the movement of the piston 62, thereby stably supplying the fluid to the dispensing device 30. While the present embodiment illustrates an example in which the piston 62 is provided and pressure is applied to the fluid via the piston 62, the present invention is not limited thereto. For example, the volume fluctuation mechanism 54 may be configured to directly apply pressure to the fluid, thereby eliminating the piston 62.

[0152] In this embodiment, the driving unit 64 is configured by a gas cylinder device (an air cylinder device in this embodiment) that can generate 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 use, as the driving unit 64, a hydraulic cylinder device that uses oil as the fluid and can generate a driving force by hydraulic pressure, or a driving unit 64x that can generate a driving force mechanically or electrically by using a motor or the like (see FIG. 23).

[0153] The present invention is not limited to the above-described embodiments and modifications. Other embodiments are possible within the scope of the appended claims, and are within the spirit and teachings of the present invention. For example, the buffer tank 50 described above has a connection 56 connected to the supply path 40 at one end of the tank portion 52, and fluid flows into and out of the tank main body 52a via the connection 56. However, a buffer tank like the one shown in FIG. 22 could be used instead. The buffer tank 150 has a configuration similar to the buffer tank 50 described above, but differs in that the connection 56c, which serves as the inlet for the fluid into the tank main body 52a, is located above the connection 56b, which serves as the outlet for the fluid from the tank main body 52a. This configuration minimizes the retention time of the fluid, further facilitating the use of the accumulated fluid.

[0154] Furthermore, in the above-described fluid discharge system 10, in the tank accumulation mode, a time limit is set for accumulating fluid in the buffer tank 50 as a measure to prevent a decrease in the supply pressure P to the discharge device 30. However, the present invention is not limited to this. For example, accumulation of fluid in the buffer tank 50 may be stopped when the supply pressure P to the discharge device 30 falls below a predetermined value. Furthermore, in the tank accumulation mode, the fluid discharge system 10 may improve the fluid supply capacity of the pump 20 compared to when operating in other operating modes, or may start operating the pump 20 earlier than the timing exemplified in the above embodiment, thereby preventing a decrease in the supply pressure P. Furthermore, the amount of fluid accumulated in the buffer tank 50 can be determined directly or indirectly by, for example, directly measuring and deriving the amount using a remaining amount sensor, detecting and subtracting the amount of fluid flowing into and out of the buffer tank 50, or the like. Alternatively, the amount of fluid can be determined indirectly by, for example, the time it takes for the fluid to flow in and out of the buffer tank 50.

[0155] Furthermore, in the above-described 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 a short time later, 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 applied to the buffer tank 50 may be increased to create 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.

[0156] Here, the above-described fluid discharge system 10 may be configured such that a sensor such as a limit switch is installed just before the lower limit of the buffer tank 50 (just before the remaining amount of fluid becomes zero), and when this 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 to switch from the combined supply mode to the next operation mode may be made by a timer (steps 5-8 and 6-8), thereby determining that the remaining amount of fluid in the buffer tank 50 has reached the lower limit. Also, instead of determining the switch from the combined supply mode to the next operation mode in this manner, a sensor may be separately installed at the lower limit of the buffer tank 50, and the switch from the combined supply mode to the next operation mode may be made on the condition that this sensor detects that the amount of fluid has decreased to the lower limit. Furthermore, the state where "the remaining amount of fluid in the buffer tank 50 is at its lower limit" may be defined as a state where the storage amount has decreased to a level where the fluid can no longer be supplied, but the present invention is not limited to this and can be defined as appropriate within the scope of the present invention. Specifically, as described in this embodiment, even if a state just before the level where the fluid can no longer 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.

[0157] In the above-described fluid dispensing system 10, a sensor 92 capable of detecting pressure is provided between the buffer tank 50 and the dispensing device 30, and each device is controlled based on the supply pressure P to the dispensing device 30; however, the present invention is not limited to this. For example, the sensor 92 may be a flow rate sensor or the like, which determines the remaining amount of fluid in the dispensing device 30 according to the flow rate of the fluid supplied to the dispensing device 30. Furthermore, if a separate accumulator is provided upstream of the dispensing device 30, the remaining amount of fluid in the dispensing device 30 may be determined based on the piston position of this accumulator, and each device may be controlled. Furthermore, the fluid dispensing system 10 is not limited to the above-described arrangement of the sensor 92. Specifically, the sensor 92 is not limited to being provided in the supply path 40, the accumulator, or the like, but may also be provided in the dispensing device 30 itself (for example, the casing 100 or the stator 104 of the dispensing device 30).

[0158] As described above, the fluid discharge system 10 may be configured, for example, by providing a remaining amount sensor in the buffer tank 50 or by providing a position sensor capable of detecting the position of the partition wall 70, and determining the amount of fluid stored in the buffer tank 50 based on the output values ​​from these sensors, or by detecting or deriving the amount of fluid flowing into and out of the buffer tank 50, and determining the amount of fluid stored in the buffer tank 50 based on the amount of fluid flowing in and out. Furthermore, the fluid discharge system 10 is not limited to a configuration in which sensors are provided at the upper or lower limit positions of the buffer tank 50 and the amount of fluid stored in multiple stages, but may also be configured to continuously detect the amount of fluid stored in the buffer tank 50.

[0159] 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, it is preferable to provide the buffer tank 50 with a detection device 300 for continuously detecting the amount of fluid stored therein. The detection device 300 shown in Fig. 24 detects the amount of fluid remaining in the buffer tank 50 by continuously detecting the position of a member (piston 62 in the illustrated example) that moves in accordance with the amount of fluid remaining, or a rod 66 or partition wall 70 that moves in conjunction with the member. In the example shown in Fig. 24, the detection device 300 includes a sensor dog 302 and a magnetic position detection sensor 304.

[0160] 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 amount of fluid remaining in the buffer tank 50, such as the piston portion 62, rod portion 66, and partition wall 70 that form 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.

[0161] 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 over which the sensor dog 302 moves in response to an increase or decrease in the amount of fluid stored in the buffer tank 50 is its 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 range of movement over 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.

[0162] 24, the fluid discharge system 10 can grasp the remaining amount of fluid in the buffer tank 50 by relating the relationship between the tank volume (remaining amount of fluid) of the buffer tank 50 and 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.

[0163] 24 , the upper and lower limits of the amount of fluid stored in the buffer tank 50 can be set or changed as needed, thereby controlling the operation of the fluid dispensing system 10. Specifically, when detecting devices such as limit switches and sensors are provided at the positions that define the upper and lower limits of the amount of fluid stored in the buffer tank 50, as in the above embodiment, the installation position of the detecting device must be physically moved in order to change the upper and lower limits of the amount of fluid stored. However, by using the above-described detecting device 300, the upper and lower limits can be set or changed as needed within the range in which the magnetic position detecting sensor 304 can detect the sensor dog 302, thereby controlling the operation of the fluid dispensing system 10.

[0164] Furthermore, in the detection device 300, it is preferable to be able 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 dispensing 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.

[0165] Specifically, as shown in Fig. 25, a remaining amount display unit 312 may be provided that indicates the remaining amount of fluid in the buffer tank 50, and the remaining amount may be displayed using an indicator, a numerical value, or the like (an indicator in the illustrated example). By visualizing the remaining amount of fluid in the buffer tank 50 in this way, it becomes clear when to refill the fluid in the storage unit 22 in which the pump 20 is located, 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).

[0166] When a user interface 310 such as that shown in Fig. 25 is provided, a mode display unit 314 may be provided that displays, in addition to or instead of the remaining amount of fluid in the buffer tank 50, the operating mode of the fluid dispensing system 10 so that it can be identified. In the mode display unit 314 shown in Fig. 25, the display indicating the current operating mode is displayed in a color that is inverted from the display indicating other operating modes, making it possible to identify the operating mode. This makes it possible to intuitively understand the operating mode of the fluid dispensing system 10 and clearly know when to replace the storage unit 22 or refill the storage unit 22 with fluid.

[0167] The timing for replacing the storage portion 22 or refilling the storage portion 22 with fluid can be specified as appropriate, but in the fluid dispensing system 10 according to the above embodiment, it is preferable to perform these operations while the system is operating in the tank supply mode. Therefore, as shown in Fig. 25, if the mode display unit 314 is configured to clearly indicate that the operating state of the fluid dispensing system 10 has entered the tank supply mode, the timing for replacing the storage portion 22 or refilling the storage portion 22 with fluid can be clearly understood.

[0168] Furthermore, when a user interface 310 such as that shown in Fig. 25 is provided, it is preferable that a display portion such as an indicator displayed thereon (remaining amount display portion 312 in the illustrated example) can receive operations, so that operation commands can be output to each portion or operation settings can be configured in accordance with the operations. For example, in the example of Fig. 25, it is preferable that an operation can be received at the display portion of the indicator in the remaining amount display portion 312, so that the length of the indicator can be adjusted. This allows the operator to intuitively perform tasks such as outputting a warning or setting either or both of the upper and lower limits of the remaining amount of fluid in the buffer tank 50, which serve as indicators of the operating conditions.

[0169] The present invention is not limited to the above-described embodiments and variations thereof, and other embodiments may be possible within the scope of the claims. The components of the above-described embodiments may be arbitrarily selected and combined. Furthermore, any component of the embodiments may be arbitrarily combined with any component described in the Summary of the Invention or any component embodying any component described in the Summary of the Invention. The present invention intends to obtain rights to these as well through amendments to this application or divisional applications, etc. [Industrial Applicability]

[0170] The present invention can be suitably used in all fluid discharge systems for pumping and discharging fluids. [Explanation of symbols]

[0171] 10: Fluid discharge system 20: Pump 22: Storage section 30:Discharge device 40: Supply route 50: Buffer tank 52: Tank section 54: Volume fluctuation mechanism 58: Communication space 60: Non-communicating space 62: Piston part (partition wall part) 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 path connecting the discharge device and the pump so that a fluid can pass therethrough; a buffer tank capable of accumulating fluid by suction, holding the fluid, and discharging the fluid to supply the fluid to the discharge device instead of the pump; During operation in a tank accumulation mode in which the fluid is accumulated in the buffer tank, the discharge device can also continue to discharge the fluid, During operation in the tank accumulation mode, the buffer tank performs an accumulation operation of intermittently sucking and accumulating a fluid, A fluid dispensing system, characterized in that the buffer tank performs a storage operation when a sufficient amount of fluid is stored in the dispensing device.

2. a remaining amount grasping unit for grasping the remaining amount of fluid in the discharge device; The fluid discharge system according to claim 1, characterized in that in the tank accumulation mode, the timing when sufficient fluid is stored in the discharge device is determined based on the amount of fluid stored in the discharge device detected by the remaining amount grasping unit.

3. The fluid discharge system according to claim 2, characterized in that the supply of fluid to the discharge device by the pump is intermittently controlled based on the amount of fluid stored in the discharge device detected by the remaining amount grasping unit.

4. The fluid discharge system described in claim 1, characterized in that the tank accumulation mode is terminated when the tank capacity reaches an upper limit by repeating the accumulation operation, and the fluid is held until it is necessary to replace the pump and supply the fluid to the discharge device.

Images