Duplex reciprocating pump

Abstract

A double reciprocating pump of the present invention includes: a housing member; a pair of movable area partition members; a connecting shaft; a suction valve; a discharge valve; a valve mechanism; a displacement sensor that detects a contraction of an extension and contraction member of the connecting shaft; proximity sensors that respectively detect that the pair of movable area partition members have reached the end of a stroke of movement; and a controller that drives the pair of movable area partition members by switching the valve mechanism based on the output of the displacement sensor and the proximity sensors. The controller judges an overlap period in which the compression steps of one pump chamber and another pump chamber partially overlap based on judgment information that is based on the output and indicates the presence or absence, order, and time difference of detection by the displacement sensor and the proximity sensors, and drives the pair of movable area partition members in a manner that changes the judgment information according to the judgment result.

Description

Technical Field

[0001] This invention relates to a double reciprocating pump. Background Technology

[0002] Previously, a type of double reciprocating pump was known, which divided a pair of enclosed spaces into a pump chamber and a working chamber by a movable partition such as a bellows connected to the connecting shaft, and caused the connecting shaft to reciprocate by alternately introducing working fluid into the pair of working chambers, thereby causing the pump chamber to alternately compress and expand.

[0003] In this dual reciprocating pump, at the end of the reciprocating stroke of the connecting shaft, a pair of suction valves and a pair of discharge valves switch from one pump chamber side to the other. As a result, pulsations corresponding to the number of strokes are generated in the discharge flow. Such pulsations can cause various adverse effects, for example, in the manufacturing and processing fields of semiconductors, liquid crystals, solar cells, pharmaceuticals, and food. Therefore, reducing pulsations has become a crucial technical problem that urgently needs improvement.

[0004] To solve the above problems, a dual reciprocating pump is known, which, when a pair of movable partitions are driven by a switching valve mechanism and a controller, controls the overlap rate, expressed as the ratio of the overlap distance to the full stroke length of the movable partitions, in such a way that the compression steps of one pump chamber and the compression steps of the other pump chamber partially overlap, thereby reducing pulsation (see Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents Patent Document 1: Japanese Patent No. 5315550 Summary of the Invention The technical problem that the invention aims to solve However, in the dual reciprocating pump disclosed in Patent Document 1, two displacement sensors are used to continuously detect the displacement of a pair of movable partition components, and the optimal overlap rate is set based on their output to reduce pulsation. Therefore, the calculation and setting of the overlap rate is extremely complex and requires very precise control. Consequently, there is a technical problem that has not been conceived, for example, to reduce the number of sensors or to achieve simpler control with a simpler structure to reduce pulsation.

[0007] The present invention was made in view of the above circumstances, and its object is to provide a dual reciprocating pump that can be easily controlled with a simple structure and achieve reduced pulsation.

[0008] Methods for solving technical problems The present invention relates to a double reciprocating pump, comprising: a housing component having a pair of spaces formed axially therein; a pair of movable partition components respectively disposed in the pair of spaces in an axially deformable or movable manner, dividing the pair of spaces axially into a pump chamber and a working chamber; a connecting shaft connecting the pair of movable partition components in an axially telescopic manner via a telescopic component; a suction valve disposed on the suction side of the pump chamber for introducing transfer fluid into the pump chamber; a discharge valve disposed on the discharge side of the pump chamber for discharging the transfer fluid from the pump chamber; a valve mechanism for introducing working fluid into and discharging working fluid from the working chamber; a displacement sensor for detecting the retraction of the telescopic component of the connecting shaft; a proximity sensor for detecting that the pair of movable partition components have reached the end of their moving stroke; and a controller that drives the pair of movable partition components by switching the valve mechanism based on the outputs of the displacement sensor and the proximity sensor. The controller, based on judgment information that is based on the output and represents the presence or absence, detection and time difference of the displacement sensor and the proximity sensor, determines the overlap period during which the compression steps of one pump chamber partially overlap with those of another pump chamber, and drives the pair of movable partition components in a manner that changes the judgment information according to the judgment result.

[0009] In one embodiment of the present invention, the controller: based on the judgment information, determines the overlapping period during each stroke of the deformation or movement of the pair of movable partition members, and drives the pair of movable partition members such that the judgment information indicates that the detection of the displacement sensor and the proximity sensor occurs simultaneously.

[0010] In another embodiment of the present invention, the controller: when the judgment information indicates that the detection of the proximity sensor occurs before the detection of the displacement sensor, or that although the proximity sensor detects but the displacement sensor does not, determines that the start of the overlapping period is later, and drives the pair of movable partition components in a manner that reduces the time difference between the start time of deformation or movement of the pair of movable partition components in each stroke by a fixed time, until the detection of the proximity sensor and the displacement sensor occurs simultaneously.

[0011] In another embodiment of the present invention, the controller: when the judgment information indicates that the detection of the displacement sensor occurs before the detection of the proximity sensor, or that although the displacement sensor detects but the proximity sensor does not, determines that the start of the overlapping period is earlier, and drives the pair of movable partition components by increasing the time difference between the start time of deformation or movement of the pair of movable partition components in each stroke by a fixed time, until the detection of the displacement sensor and the proximity sensor occurs simultaneously.

[0012] In another embodiment of the invention, the displacement sensor is disposed on one side of the connecting shaft, away from the telescopic member, and detects the contraction of the telescopic member by detecting a detected component disposed on the other side of the shaft, away from the telescopic member. The telescopic member is preferably a coil spring.

[0013] In another embodiment of the invention, the valve mechanism includes: a pair of valves respectively disposed in a pair of said working chambers; and a pair of pressure regulators that regulate the pressure of working fluid from a working fluid supply source and supply the working fluid to the pair of valves respectively.

[0014] Another double reciprocating pump according to the present invention includes: a pump head; a pair of bottomed cylindrical bellows attached to both sides of the pump head with their open sides facing each other and forming pump chambers inside, and each capable of axial extension and retraction; a pair of bottomed cylindrical cylinders coaxially arranged relative to the pair of bellows so as to house the pair of bellows, forming a working chamber between them, and mounted on the pump head with their openings facing each other; a pair of pump shafts passing through the bottom of the pair of cylinders in an airtight and slidable manner along the central axis of the cylinders, each end of which is connected to the bottom of the pair of bellows; a connecting shaft, which passes through... A telescopic component connects the other ends of the pair of pump shafts together axially in a telescopic manner; a valve unit, mounted in the pump head within the pump chamber, introduces the transfer fluid into the pump chamber from the suction port of the delivery fluid and discharges the transfer fluid from the pump chamber to the discharge port of the delivery fluid; a valve mechanism for introducing working fluid into the working chamber and discharging the working fluid from the working chamber; a displacement sensor for detecting the contraction of the telescopic component of the connecting shaft; proximity sensors for detecting that the pair of bellows have reached the contracted end; and a controller that drives the pair of bellows by switching the valve mechanism based on the outputs of the displacement sensor and the proximity sensor. The controller, based on judgment information based on the outputs and representing the presence, sequence, and time difference of the detections by the displacement sensor and the proximity sensor, determines the overlap period during which the compression steps of one pump chamber partially overlap with those of the other pump chamber, and drives the pair of bellows in a manner that changes the judgment information according to the judgment result.

[0015] In one embodiment of the present invention, the controller: based on the judgment information, determines the overlapping period during each stroke of the extension and retraction of the pair of bellows, and drives the pair of bellows so that the judgment information indicates that the detection of the displacement sensor and the proximity sensor occurs simultaneously.

[0016] In another embodiment of the present invention, the controller: when the judgment information indicates that the detection of the proximity sensor occurs before the detection of the displacement sensor, or that although the proximity sensor detects but the displacement sensor does not, determines that the start of the overlapping period is later, and drives the pair of bellows in a manner that reduces the time difference between the start time of the contraction of the pair of bellows in each stroke by a fixed time, until the detection of the proximity sensor and the displacement sensor occurs simultaneously.

[0017] In another embodiment of the present invention, the controller: when the judgment information indicates that the detection of the displacement sensor occurs before the detection of the proximity sensor, or although the detection of the displacement sensor occurs but the detection of the proximity sensor does not, determines that the start of the overlapping period is earlier, and drives the pair of bellows by increasing the time difference between the start time of the contraction of the pair of bellows in each stroke by a fixed time, until the detection of the displacement sensor and the proximity sensor occurs simultaneously.

[0018] The effects of the invention According to the present invention, simple control and pulsation reduction can be achieved with a simple structure. Attached Figure Description

[0019] Figure 1 This is an explanatory diagram showing the schematic structure of the double reciprocating pump according to the first embodiment of the present invention.

[0020] Figure 2 This is a timing diagram showing the appropriate operation of the double reciprocating pump.

[0021] Figure 3 This is a timing diagram illustrating an example of the control operation of the double reciprocating pump.

[0022] Figure 4 This is a timing diagram illustrating another example of the control operation of the double reciprocating pump.

[0023] Figure 5 This is an explanatory diagram showing the schematic structure of the double reciprocating pump according to the second embodiment of the present invention.

[0024] Figure 6 This is an explanatory diagram showing the general structure of the double reciprocating pump.

[0025] Figure 7 This is an explanatory diagram showing a portion of the structure of the double reciprocating pump according to the third embodiment of the present invention.

[0026] Explanation of reference numerals in the attached figures 1 pump head Cylinders 2a and 2b 3a bellows L 3b bellows R 4a, 4b axis fixing plates 5a, 5b pump rooms 6a, 6b Action Room 7a, 7b axes 9a, 9b connecting plates 11a, 11b connecting shafts 12 shaft L 13 shaft R 14-coil spring 16 suction port 17 discharge outlets 21a Proximity Switch (SW) L 21b Proximity Switch (SW)R 23a Displacement Sensor (Photoelectric Miniature Sensor) 23b detection board 23C Detection Body 25 controllers 26a voltage regulator L 26b voltage regulator R 27a Solenoid Valve L 27b Solenoid Valve R 100 Double Reciprocating Bellows Pump Detailed Implementation Hereinafter, with reference to the accompanying drawings, a detailed description of the double reciprocating pump according to embodiments of the present invention will be provided. However, the following embodiments do not limit the invention to the scope of the claims, and not all combinations of features described in the embodiments are necessary for the solution of the invention. Furthermore, in the following embodiments, the same or equivalent constituent elements are given the same reference numerals and repeated descriptions are omitted. Additionally, in the embodiments, the arrangement, proportions, and dimensions of each constituent element are sometimes exaggerated or reduced to represent a state inconsistent with reality, and sometimes the description of some constituent elements is omitted.

[0027] [First Embodiment] [Structure of a double reciprocating pump] Figure 1 This is an explanatory diagram illustrating the schematic structure of a double reciprocating pump according to an embodiment of the present invention, for example showing a cross-section of a double reciprocating bellows pump and its surrounding mechanisms. It should be noted that... Figure 1 The diagram shows a cross-section of the double reciprocating bellows pump as viewed from the front, therefore, along... Figure 1 The left and right directions on the paper plane represent the left and right directions and the axial direction of the double reciprocating bellows pump, while the direction orthogonal to the left and right directions and along the paper plane represents the up and down directions.

[0028] like Figure 1 As shown, the double reciprocating bellows pump (hereinafter referred to as the "bellows pump") 100 includes: a pump head 1, and a pair of cylinders 2a and 2b as housing components. The pump head 1 is located at the center of the bellows pump 100. The cylinders 2a and 2b are formed into bottomed cylindrical shapes and are coaxially arranged on the left and right sides of the pump head 1 along its axial direction.

[0029] Inside cylinders 2a and 2b, a pair of axially oriented spaces (internal spaces) are formed. Within these two internal spaces, bellows L3a and R3b, which are capable of axial expansion and contraction (deformation or movement), are coaxially arranged. Bellows L3a and R3b, as a pair of movable partition components, are formed into bottomed cylindrical shapes, and their open ends, which serve as openings, are fixed to pump head 1.

[0030] At the bottom of bellows L3a and bellows R3b, shaft fixing plates 4a and 4b are fixed respectively. These bellows L3a and bellows R3b constitute movable partition components that divide the internal spaces of cylinders 2a and 2b axially into inner pump chambers 5a and 5b and outer actuation chambers 6a and 6b respectively.

[0031] One end of the coaxially extending shafts 7a and 7b is fixed to shaft fixing plates 4a and 4b, respectively. Shafts 7a and 7b constitute a pair of pump shafts. Shafts 7a and 7b, respectively, pass through the bottom center of cylinders 2a and 2b in an airtight and slidable manner via sealing components 8 and extend to the outside. The other ends of shafts 7a and 7b are fixed to connecting plates 9a and 9b, respectively, by nuts 10.

[0032] Connecting plates 9a and 9b are connected above and below cylinders 2a and 2b respectively via connecting shafts 11a and 11b. Each connecting shaft 11a and 11b consists of a rod-shaped shaft portion L12, a shaft portion R13, and a coil spring 14 disposed between shaft portion L12 and shaft portion R13 as a telescopic component.

[0033] Each connecting shaft 11a, 11b has its shaft portion L12 and shaft portion R13 on the side opposite to the coil spring 14, which are screwed and fixed to the connecting plates 9a, 9b by bolts 15. Therefore, each connecting shaft 11a, 11b, through the connecting plates 9a, 9b, shafts 7a, 7b, and shaft fixing plates 4a, 4b, connects a pair of indirectly connected bellows 3a, 3b via the coil spring 14 in a manner that allows for free axial extension and retraction.

[0034] On the other hand, in the pump head 1, for example, a suction port 16 and a discharge port 17 for conveying fluid are provided on the side facing the pump. The suction port 16 and the discharge port 17 are positioned offset circumferentially from the positions of the connecting shafts 11a and 11b. Furthermore, as valve units, suction valves 18a and 18b are provided on the suction side of the pump head 1, i.e., from the suction port 16 to the pump chambers 5a and 5b. And discharge valves 19a and 19b are provided on the path from the pump chambers 5a and 5b of the pump head 1 to the discharge port 17 on the discharge side.

[0035] It should be noted that proximity switches (SW) L21a and R21b, which serve as proximity sensors, are installed on the bottom outer wall of cylinders 2a and 2b. Proximity switches L21a and R21b detect when connecting plates 9a and 9b are in the closest state (bellows L3a and R3b are in the most retracted state (retracted end)).

[0036] Additionally, a displacement sensor 23a is installed on one of the connecting shafts 11a and 11b, for example, on the upper connecting shaft 11a. The displacement sensor 23a is, for example, located at the end of the coil spring 14 side of the shaft portion L12 of the connecting shaft 11a. The displacement sensor 23a detects that the coil spring 14 of the connecting shaft 11a has contracted (become flattened).

[0037] The displacement sensor 23a can be composed of, for example, a photoelectric micro-sensor, a proximity sensor, a photoelectric sensor, a fiber optic sensor, an ultrasonic sensor, and physical contact switches such as microswitches and limit switches. In this embodiment, the displacement sensor 23a is composed of a photoelectric micro-sensor.

[0038] In this case, since the displacement sensor 23a is disposed on the shaft portion L12 of the connecting shaft 11a on one side separated from the coil spring 14, as described above, a detection plate 23b, serving as the detected component, is mounted on the shaft portion R13 on the other side separated from the coil spring 14. The detection plate 23b is mounted, for example, on the end of the shaft portion R13 on the coil spring 14 side, such that its top end reaches the displacement sensor 23a when the coil spring 14 contracts.

[0039] The displacement sensor 23a detects the contraction of the coil spring 14 by detecting the top end of the detection plate 23b. That is, it can detect that the discharge from pump chambers 5a and 5b is in an overlapping state. It should be noted that the displacement sensor 23a and the detection plate 23b can also be interchanged and respectively disposed on shaft L12 and shaft R13. Furthermore, in this example, the displacement sensor 23a and the detection plate 23b are disposed above the connecting shaft 11a, but they can also be disposed to the side or below the connecting shaft 11a. Additionally, in this example, the displacement sensor 23a and the detection plate 23b are disposed above the bellows pump 100 on shaft L12 and shaft R13, but they can also be disposed below the bellows pump 100 on shaft L12 and shaft R13.

[0040] Digital detection signals (detection outputs) from proximity switches L21a and R21b, and displacement sensor 23a are input to controller 25. Additionally, a moving fluid, such as air, from a source not shown (e.g., an air compressor), is supplied to a specified pressure via a pair of pressure regulators L26a and R26b, and then supplied as a pair of solenoid valves L27a and R27b. The valve mechanism includes these pressure regulators L26a and R26b, and the solenoid valves L27a and R27b.

[0041] Solenoid valves L27a and R27b are used to introduce air into and exhaust air from actuation chambers 6a and 6b. Controller 25 receives the detection outputs from proximity switches L21a and R21b, and displacement sensor 23a, and controls the opening and closing of solenoid valves L27a and R27b based on these detection outputs. Thus, controller 25 drives a pair of bellows L3a and R3b by switching solenoid valves L27a and R27b.

[0042] Specifically, the controller 25, based on the judgment information indicating the presence, detection, and time difference of the displacement sensor 23a and proximity switches L21a and R21b, which is based on the aforementioned detection output, determines the overlap period during which the compression steps of one pump chamber 5a (or 5b) partially overlap with those of another pump chamber 5b (or 5a). Then, the controller 25 drives a pair of bellows L3a and R3b according to the judgment result, causing the judgment information—namely, the presence, sequence, and time difference of the detection—to change.

[0043] It should be noted that, based on the judgment information, the controller 25 determines the overlap period for each stroke of the extension and retraction of the pair of bellows L3a and R3b. Then, the controller 25 drives the pair of bellows L3a and R3b so that the judgment information indicates that the detection of displacement sensor 23a and proximity switches L21a and R21b occurs simultaneously.

[0044] [Pump Operation] Next, the operation of the double reciprocating bellows pump of this embodiment will be explained.

[0045] Figure 2 This is a timing diagram showing the appropriate operation of a double reciprocating pump.

[0046] As described above, air from the actuating fluid supply source is restricted to a specified pressure by pressure regulators L26a and R26b, and then supplied to solenoid valves L27a and R27b.

[0047] Therefore, pressure changes in one actuating chamber 6a (or 6b) will not affect the pressure in the other actuating chamber 6b (or 6a), thus confirming the resulting reduction in pulsation. It should be noted that the pressure regulator is not limited to two as described above; a single regulator may also be used. In this case, a so-called precision pressure regulator is preferred.

[0048] Here, in the bellows pump 100, for example, the solenoid valve L27a is set to be in the venting state (OFF state), the solenoid valve R27b is set to be in the air supply state (ON state), and the pump chamber 5a is in the expansion step and the pump chamber 5b is in the contraction step. At this time, the suction valve 18a and the discharge valve 19b are open, and the suction valve 18b and the discharge valve 19a are closed. Therefore, the conveying fluid is introduced into the pump chamber 5a from the suction port 16 and discharged from the pump chamber 5b through the discharge port 17.

[0049] On the other hand, the system is configured such that solenoid valve L27a is in the air supply state (ON state), solenoid valve R27b is in the air discharge state (OFF state), and pump chamber 5a is in the contraction phase and pump chamber 5b is in the expansion phase. At this time, suction valve 18a and discharge valve 19b are closed, and suction valve 18b and discharge valve 19a are open. Therefore, the conveying fluid is introduced into pump chamber 5b from suction port 16 and discharged from pump chamber 5a through discharge port 17.

[0050] Furthermore, in order to reduce pulsation, for example, by switching solenoid valves L27a and R27b, the overlap period of pump chamber 5b maintaining compression when pump chamber 5a switches from expansion step to compression step and pump chamber 5a maintaining compression step when pump chamber 5b switches from expansion step to compression step is set so that the timing of overlap from the discharge of pump chambers 5a and 5b is appropriate.

[0051] During this overlap period, because solenoid valves L27a and R27b are in the ON state and introduce air into the actuation chambers 6a and 6b, the suction valves 18a and 18b are closed, and the discharge valves 19a and 19b are opened, discharging the conveyed fluid from the two pump chambers 5a and 5b. That is, when bellows L3a and R3b are simultaneously in the contracted state, the coil spring 14 connecting shafts 11a and 11b is compressed and contracted (flattened) to absorb the dimensional change between the two ends of bellows L3a and R3b.

[0052] Controlled by controller 25, at a time T1 seconds after solenoid valve L27a switches from exhaust state to supply state (bellows L3a contraction step), solenoid valve R27b switches from exhaust state to supply state (bellows R3b contraction step). Subsequently, after the overlap period OP, when proximity switch L21a detects the end of the stroke (bellows 3a contraction end), displacement sensor 23a also turns ON at the same time, if the action is appropriate. Accordingly, solenoid valve L27a switches from supply state to exhaust state.

[0053] Similarly, under the control of controller 25, at a time T2 seconds after solenoid valve R27b switches from the exhaust state to the supply state (the contraction step of bellows R3b), solenoid valve L27a switches from the exhaust state to the supply state (the contraction step of bellows L3a). Subsequently, after the overlap period OP, when proximity switch R21b detects the end of the stroke (the contraction end of bellows 3b), displacement sensor 23a also turns ON at the same time, if the action is appropriate. Accordingly, solenoid valve R27b switches from the supply state to the exhaust state. By repeating this action in the left and right pump chambers 5a and 5b, bellows pump 100 can perform an appropriate action to reduce pulsation.

[0054] exist Figure 2 In this diagram, for each stroke of bellows L3a and R3b, it is appropriately shown that the left and right pump chambers 5a and 5b are both in the overlapping period of the compression step (OP). In this case, it can be seen that the alternating detection (ON) of each proximity switch L21a and proximity switch R21b and the detection (ON) of displacement sensor 23a occur simultaneously. That is, it can be known that bellows L3a and R3b have completed the full stroke up to the contraction end (end of discharge), and the pulsation has decreased.

[0055] It should be noted that, as mentioned above, when the operation is appropriate, the time difference from the moment solenoid valve L27a switches from the exhaust state to the supply state (supply start), i.e., the start of bellows L3a's discharge, to the moment solenoid valve R27b subsequently switches from the exhaust state to the supply state (supply start), i.e., the start of bellows R3b's discharge, is T1 seconds. Furthermore, the time difference from the moment solenoid valve R27b switches from the exhaust state to the supply state (supply start), i.e., the start of bellows R3b's discharge, to the moment solenoid valve L27a subsequently switches from the exhaust state to the supply state (discharge start), i.e., the start of bellows L3a's discharge, is T2 seconds. Therefore, when the pump operates appropriately with reduced pulsation, the pair of bellows L3a and R3b maintain a constant time difference of T1 seconds and T2 seconds respectively for the overlapping discharge start times, while completing the full stroke operation with equally spaced overlap periods OP for each stroke.

[0056] When the time differences T1 seconds and T2 seconds are constant and appropriate, this situation can be detected by the simultaneous alternating detection of each proximity switch L21a and proximity switch R21b and the detection of displacement sensor 23a. Therefore, even if the pump's operating conditions (air and liquid piping conditions, supply air pressure, discharge load, etc.) change, the controller 25 can control the pump to perform appropriate actions based on the judgment information from each sensor 21a, 21b, and 23a.

[0057] It should be noted that even if the bellows L3a and R3b do not complete their full stroke, pulsation can be suppressed when the coil spring 14 is flattened. However, in this case, the solenoid valves L27a and R27b will repeatedly perform unnecessary air supply and exhaust, resulting in increased energy consumption due to increased air consumption and reduced lifespan of the solenoid valves L27a and R27b. Therefore, the bellows should be made to complete their full stroke as much as possible. To prevent such problems, proximity switches L21a and R21b are essential.

[0058] Figure 3 This is a timing diagram illustrating an example of the control operation of a double reciprocating pump. Figure 4 This is a timing diagram illustrating another example of the control action of a double reciprocating pump. Figure 3 The control action is shown in the case where the timing of the start of overlapping discharges is delayed, while Figure 4 The control action is shown in the case where the timing of the discharge overlap is earlier than expected.

[0059] like Figure 3As shown, if the judgment information indicates that the detection of proximity switches L21a and R21b precedes the detection of displacement sensor 23a, or if proximity switches L21a and R21b are detected but displacement sensor 23a is not, the controller 25 determines that the start of the overlap period OP is late, that is, the time at which the discharge begins to overlap is late. In this case, it can be known that bellows L3a and R3b have completed their full stroke up to the contraction end (end of discharge), and the pulsation has not been reduced.

[0060] Therefore, the controller 25 drives a pair of bellows L3a and bellows R3b to reduce the time difference T1 seconds and T2 seconds at the start of the contraction (discharge) of the pair of bellows L3a and bellows R3b by a fixed time (Δt) in each stroke until the (alternating) detection of proximity switches L21a and R21b and the detection of displacement sensor 23a occur simultaneously.

[0061] First, the operating mode (A) in which bellows R3b begins to discharge after bellows L3a begins to discharge will be explained. In this operating mode (A), when bellows L3a begins to discharge and bellows R3b begins to discharge after a time difference T1 seconds, solenoid valve L27a begins supplying air at the start of bellows L3a's discharge. At this time, bellows R3b reaches the contraction end (discharge complete) and proximity switch R21b is in the ON state. However, because the coil spring 14 connecting shafts 11a and 11b has not contracted, displacement sensor 23a is in the OFF state.

[0062] Subsequently, at the start of the discharge from bellows R3b after T1 seconds, solenoid valve R27b begins supplying air. At this time, bellows L3a reaches the contraction end (discharge complete) and proximity switch L21a is in the ON state. However, because the coil spring 14 connecting shafts 11a and 11b has not contracted, displacement sensor 23a remains in the OFF state. Therefore, controller 25 changes the start time of discharge by changing the time difference from T1 seconds to a time difference T1′ (T1′ = T1 - Δt) seconds minus a fixed time (Δt).

[0063] Next, when bellows L3a begins to discharge and bellows R3b begins to discharge after a time difference T1′ seconds, solenoid valve L27a begins to supply air at the start of bellows L3a's discharge. At this time, solenoid valve R27b is in the air supply state and bellows R3b is in the contraction step. After a small overlap period OP, bellows R3b reaches the contraction end (discharge ends) and proximity switch R21b becomes ON, but displacement sensor 23a remains OFF.

[0064] Subsequently, at the start of the discharge from bellows R3b after T1′ seconds, solenoid valve R27b begins supplying air. At this time, solenoid valve L27a is in the air supply state and bellows L3a is in the contraction step. After generating an additional overlap period OP compared to the previous period, bellows L3a reaches the contraction end (discharge ends) and proximity switch L21a becomes ON, but displacement sensor 23a becomes ON later. That is, proximity switch L21a becomes ON before displacement sensor 23a. Therefore, the start time of discharge is changed by changing the time difference from T1′ seconds to a time difference T1″ (T1″ = T1′ - Δt) seconds minus a fixed time (Δt).

[0065] Next, when bellows L3a begins to discharge and bellows R3b begins to discharge after a time difference T1″, solenoid valve L27a begins to supply air at the start of bellows L3a's discharge. At this time, solenoid valve R27b is in the air supply state and bellows R3b is in the contraction step. After generating the same overlap period OP as after T1′ seconds, bellows R3b reaches the contraction end (discharge ends) and proximity switch R21b becomes ON, but displacement sensor 23a becomes ON with a slight delay. That is, proximity switch R21b still becomes ON before displacement sensor 23a.

[0066] Subsequently, at the start of the discharge from bellows R3b after T1″ seconds, solenoid valve R27b begins to supply air. At this time, solenoid valve L27a is in the air supply state and bellows L3a is in the contraction step. After generating an overlap period OP that is longer than after T1′ seconds, bellows L3a reaches the contraction end (discharge ends) and proximity switch L21a and displacement sensor 23a simultaneously become ON.

[0067] In this situation, the controller 25 determines that bellows L3a and R3b have completed their full stroke and the pulsation has decreased, indicating they are in a suitable operating state. Thereafter, it no longer changes the time difference T1″ seconds, but repeatedly switches between solenoid valves L27a and R27b. Figure 3 The example shown illustrates how subtracting a fixed time (Δt) from the time difference T1 seconds in each stroke and repeating this operation twice makes it appropriate for the timing of the discharge from pump chambers 5a and 5b to begin to overlap.

[0068] On the other hand, the operating mode (B) in which bellows L3a begins to discharge after bellows R3b begins to discharge will be explained. In this operating mode (B), when bellows R3b begins to discharge and bellows L3a begins to discharge after a time difference T2 seconds, solenoid valve R27b begins to supply air at the start of bellows R3b's discharge. At this time, bellows L3a reaches the contraction end (discharge ends) and proximity switch L21a is in the ON state, but because the coil spring 14 connecting shafts 11a and 11b has not contracted, displacement sensor 23a is in the OFF state.

[0069] Subsequently, at the start of the discharge from bellows L3a after T2 seconds, solenoid valve L27a begins supplying air. At this time, solenoid valve R27b is in the air supply state and bellows R3b is in the contraction step. After a small overlap period OP, bellows R3b reaches the contraction end (discharge ends) and proximity switch R21b becomes ON, but displacement sensor 23a is OFF. Therefore, the start time of discharge is changed by changing the time difference from T2 seconds to a time difference T2′ (T2′ = T2 - Δt) seconds minus a fixed time (Δt).

[0070] Next, when bellows R3b begins to discharge and bellows L3a begins to discharge after a time difference T2′ seconds, solenoid valve R27b begins to supply air at the start of bellows R3b's discharge. At this time, solenoid valve L27a is in the air supply state and bellows L3a is in the contraction step. After an additional overlap period OP compared to T2 seconds later, bellows L3a reaches the contraction end (discharge ends) and proximity switch L21a becomes ON, but displacement sensor 23a becomes ON later. That is, proximity switch L21a becomes ON before displacement sensor 23a.

[0071] Subsequently, at the start of the discharge from bellows L3a after T2′ seconds, solenoid valve L27a begins supplying air. At this time, solenoid valve R27b is in the air supply state and bellows R3b is in the contraction step. After generating the same overlap period OP as the previous period, bellows R3b reaches the contraction end (discharge ends) and proximity switch R21b becomes ON, but displacement sensor 23a becomes ON with a slight delay. That is, proximity switch R21b still becomes ON before displacement sensor 23a. Therefore, by changing the time difference from T2′ seconds to a time difference T2″ (T2″ = T2′ - Δt) seconds that is further subtracted from the fixed time (Δt), the start time of discharge is changed.

[0072] Next, when bellows R3b begins to discharge and bellows L3a begins to discharge after a time difference T2″ seconds, solenoid valve R27b begins to supply air at the start of bellows R3b's discharge. At this time, solenoid valve L27a is in the air supply state and bellows L3a is in the contraction step. After generating an overlap period OP that is longer than after T2′ seconds, bellows L3a reaches the contraction end (discharge ends) and proximity switch L21a and displacement sensor 23a simultaneously become ON.

[0073] Subsequently, at the start of the discharge of bellows L3a after T2″, solenoid valve L27a begins to supply air. At this time, solenoid valve R27b is in the air supply state and bellows R3b is in the contraction step. After generating the same overlapping period OP as the previous period, bellows R3b reaches the contraction end (discharge ends) and proximity switch R21b and displacement sensor 23a simultaneously become ON.

[0074] In this situation, the controller 25 determines that bellows R3b and L3a have completed their full stroke and the pulsation has decreased, indicating they are in a suitable operating state. Thereafter, it no longer changes the time difference T2″ seconds, but repeatedly switches between solenoid valves R27b and L27a. Figure 3 The example shown illustrates how subtracting a fixed time (Δt) from the time difference T2 seconds in each stroke and repeating this operation twice makes it appropriate for the timing of the start of overlap of the discharge from pump chambers 5b and 5a to be appropriate.

[0075] Thus, when the timing of the overlapping discharge of bellows L3a and R3b is relatively late, the bellows pump 100 alternately repeats the above-mentioned operating mode (A) and operating mode (B) in each stroke until the detection of proximity switch L21a and proximity switch R21b and the detection of displacement sensor 23a occur simultaneously. The starting time of discharge is changed by gradually reducing the fixed time (Δt) in each stroke by the time difference T1 seconds and T2 seconds between the start times of discharge.

[0076] Therefore, even if the moment when the discharge begins to overlap is delayed due to changes in the pump's operating conditions as described above, the system can automatically track the judgment information (e.g., the start time of discharge) based on the detection outputs from each of the sensors 21a, 21b, and 23a and change that information (e.g., change the start time) to achieve appropriate action to reduce pulsation, thereby performing pump operation.

[0077] On the other hand, such as Figure 4As shown, if the judgment information indicates that the detection of displacement sensor 23a precedes the detection of proximity switches L21a and R21b, or if displacement sensor 23a is detected but proximity switches L21a and R21b are not, the controller 25 determines that the start of the overlap period OP is too early, that is, the time when the discharge begins to overlap is too early. In this case, it can be seen that although the pulsation has been reduced, bellows L3a and R3b have not completed the full stroke to the contraction end (end of discharge).

[0078] Therefore, the controller 25 drives a pair of bellows L3a and bellows R3b to increase the time difference T1 seconds and T2 seconds between the start times of the contraction (discharge) of the pair of bellows L3a and bellows R3b in each stroke by a fixed time (Δt) until the detection of displacement sensor 23a and the (alternating) detection of proximity switch L21a and proximity switch R21b occur simultaneously.

[0079] First, the operating mode (C) in which bellows R3b begins to discharge after bellows L3a begins to discharge will be explained. In this operating mode (C), when bellows L3a begins to discharge and bellows R3b begins to discharge after a time difference T1 seconds, solenoid valve L27a begins to supply air at the start of bellows L3a's discharge. At this time, since bellows R3b is in the contraction phase, after the overlap period OP, solenoid valve R27b begins to discharge air before reaching the contraction end. Therefore, proximity switch R21b remains OFF, and because the coil spring 14 connecting shafts 11a and 11b is in the contracted state, displacement sensor 23a becomes ON.

[0080] Subsequently, at the start of the discharge from bellows R3b after T1 seconds, solenoid valve R27b begins to supply air. At this time, since bellows L3a is in the contraction phase, solenoid valve L27a also begins to discharge air after the overlap period OP, before reaching the contraction end. Therefore, proximity switch L21a remains OFF, and because the coil spring 14 connecting shafts 11a and 11b is in the contracted state, displacement sensor 23a becomes ON. Thus, the start time of discharge is changed by altering the time difference from T1 seconds to a time difference T1′ (T1′ = T1 + Δt) seconds that has been increased by a fixed time (Δt).

[0081] Next, when bellows L3a begins to discharge and bellows R3b begins to discharge after a time difference T1′ seconds, solenoid valve L27a begins to supply air at the start of bellows L3a's discharge. At this time, since bellows R3b is in the contraction phase, solenoid valve R27b also begins to discharge air after the overlap period OP, before reaching the contraction end. Therefore, proximity switch R21b remains OFF, while displacement sensor 23a becomes ON.

[0082] Subsequently, at the start of the discharge from bellows R3b after T1′ seconds, solenoid valve R27b begins to supply air. At this time, since bellows L3a is in the contraction phase, solenoid valve L27a also begins to discharge air after the overlap period OP, before reaching the contraction end. Therefore, proximity switch L21a remains OFF, while displacement sensor 23a becomes ON. Thus, the start time of discharge is changed by altering the time difference from T1′ seconds to a time difference T1″ (T1″ = T1′ + Δt) seconds, which is increased by a fixed time (Δt).

[0083] Next, when bellows L3a begins to discharge and bellows R3b begins to discharge after a time difference T1″, solenoid valve L27a begins to supply air at the start of bellows L3a's discharge. At this time, since bellows R3b is in the contraction phase, solenoid valve R27b also begins to discharge air after the overlap period OP, just before reaching the contraction end. Therefore, proximity switch R21b remains OFF, while displacement sensor 23a becomes ON.

[0084] Subsequently, at the start of the discharge from bellows R3b after T1″, solenoid valve R27b begins to supply air. At this time, since bellows L3a is in the contraction phase, similarly, after the overlap period OP, the contraction end (discharge ends) is reached and proximity switch L21a and displacement sensor 23a simultaneously become ON.

[0085] In this situation, the controller 25 determines that the pulsation has decreased and the bellows L3a has completed its full stroke and is in a suitable operating state. Thereafter, it no longer changes the time difference T1″ seconds, but repeatedly switches between solenoid valves L27a and R27b. Figure 4 The example shown illustrates how adding a fixed time (Δt) to the time difference T1 seconds in each stroke and repeating this operation twice makes it appropriate for the timing of the discharge from pump chambers 5a and 5b to begin to overlap.

[0086] On the other hand, the operating mode (D) in which bellows L3a begins to discharge after bellows R3b begins to discharge will be explained. In this operating mode (D), when bellows R3b begins to discharge and bellows L3a begins to discharge after a time difference T2 seconds, solenoid valve R27b begins to supply air at the start of bellows R3b's discharge. At this time, since bellows L3a is in the contraction phase, solenoid valve L27a begins to discharge air after the overlap period OP, before reaching the contraction end. Therefore, proximity switch L21a remains OFF, and since the coil spring 14 connecting shafts 11a and 11b is in the contracted state, displacement sensor 23a becomes ON.

[0087] Subsequently, at the start of the discharge from bellows L3a after T2 seconds, solenoid valve L27a begins to supply air. At this time, since bellows R3b is in the contraction phase, solenoid valve R27b also begins to discharge air after the overlap period OP, before reaching the contraction end. Therefore, proximity switch R21b remains OFF, while displacement sensor 23a becomes ON. Thus, the start time of discharge is changed by adding a fixed time (Δt) to the time difference T2 seconds, resulting in a time difference T2′ (T2′ = T2 + Δt) seconds.

[0088] Next, when bellows R3b begins to discharge and bellows L3a begins to discharge after a time difference T2′ seconds, solenoid valve R27b begins to supply air at the start of bellows R3b's discharge. At this time, since bellows L3a is in the contraction phase, solenoid valve L27a also begins to discharge air after the overlap period OP, before reaching the contraction end. Therefore, proximity switch L21a remains OFF, while displacement sensor 23a becomes ON.

[0089] Subsequently, at the start of the discharge from bellows L3a after T2′ seconds, solenoid valve L27a begins to supply air. At this time, since bellows R3b is in the contraction phase, solenoid valve R27b also begins to discharge air after the overlap period OP, just before reaching the contraction end. Therefore, proximity switch R21b remains OFF, while displacement sensor 23a becomes ON. Thus, the start time of discharge is changed so that the time difference is T2′ seconds plus a fixed time (Δt) resulting in a time difference T2″ (T2″ = T2′ + Δt) seconds.

[0090] Next, when bellows R3b begins to discharge and bellows L3a begins to discharge after a time difference T2″, solenoid valve R27b begins to supply air at the start of bellows R3b's discharge. At this time, since bellows L3a is in the contraction phase, similarly, after the overlap period OP, bellows L3a reaches the contraction end (discharge ends) and proximity switch L21a and displacement sensor 23a simultaneously become ON.

[0091] Subsequently, at the start of the discharge of bellows L3a after T2″, solenoid valve L27a begins to supply air. At this time, since bellows R3b is in the contraction step, similarly, after the overlap period OP, bellows R3b reaches the contraction end (discharge ends), and proximity switch R21b and displacement sensor 23a simultaneously become ON.

[0092] In this situation, the controller 25 determines that the pulsation has decreased and the bellows R3b has completed its full stroke and is in a suitable operating state. Thereafter, it no longer changes the time difference T2″ seconds, but repeatedly switches between solenoid valves R27b and L27a. Figure 4 The example shown illustrates how adding a fixed time (Δt) to the time difference T2 seconds in each stroke and repeating the operation twice makes it appropriate for the timing of the discharge from pump chambers 5b and 5a to begin to overlap.

[0093] Thus, when the timing of the overlapping discharge of bellows L3a and R3b occurs too early, the bellows pump 100 alternately repeats the above-mentioned operating mode (C) and operating mode (D) in each stroke, so that the time difference T1 seconds and T2 seconds at the start of discharge are gradually increased by a fixed time (Δt) in each stroke to change the start time, until the detection of displacement sensor 23a and the detection of proximity switch L21a and proximity switch R21b occur simultaneously.

[0094] Therefore, even if the timing of the discharge start overlaps too early due to changes in the pump's operating conditions as described above, the system can automatically track the judgment information (e.g., the start time of discharge) based on the detection outputs from each of the sensors 21a, 21b, and 23a and change that information (e.g., change the start time) to achieve appropriate action to reduce pulsation, thereby performing pump operation.

[0095] It should be noted that, compared with conventional double reciprocating pumps, the bellows pump 100 of this embodiment does not require multiple displacement sensors that output analog detection signals, but can use a single displacement sensor 23a that outputs digital detection signals. Therefore, an A / D converter is not needed in the controller 25, so even processors with lower processing power can handle it. Furthermore, it simplifies the circuit, reduces the size of the circuit board, lowers power consumption, and reduces noise, resulting in an overall cost reduction.

[0096] Furthermore, in conventional double reciprocating pumps, two laser displacement sensors are used as displacement sensors. However, in environments with high ambient temperatures or exposed to flammable gases, vapors, dust, etc., laser oscillation may not be possible without forced cooling such as air purging, or explosion-proof specifications may be required, thus posing a risk of measurement failure or unusability. For example, when using the pump in wafer cleaning equipment, cleaning fluids with temperatures up to approximately 180°C are sometimes transported as the delivery fluid, or IPA is transported as a solvent, requiring cooling equipment and energy consumption to handle high temperatures, or explosion-proof specifications.

[0097] In contrast, the bellows pump 100, as a displacement sensor 23a, can use a proximity sensor that is more resistant to high-temperature environments and has explosion-proof specifications than the laser displacement sensor. Therefore, even in places where the ambient temperature of the pump is high or in an explosion-proof environment, the contraction of the coil spring 14 can be properly detected without cooling.

[0098] Furthermore, sensors that output analog detection signals, such as laser displacement sensors, are generally more expensive, larger, and require more wiring compared to sensors that output digital detection signals, such as photoelectric micro-sensors. For example, each laser displacement sensor requires at least four wires (power line × 2 + signal line × 2). As a result, a conventional double reciprocating pump requires a total of 14 wires, while the bellows pump 100 eliminates the need for a laser displacement sensor and reduces the number of sensors required, necessitating only 9 wires. This reduces costs, wiring workload, and the risk of sensor damage or malfunction due to incorrect wiring, while also enabling pump miniaturization.

[0099] [Second Embodiment] Figure 5 and Figure 6 This is an explanatory diagram showing the schematic structure of the double reciprocating pump according to the second embodiment of the present invention.

[0100] In the bellows pump 100 of the first embodiment, each connecting shaft 11a, 11b has a coil spring 14 installed at approximately the midpoint between shaft portion L12 and shaft portion R13, but as Figure 5 As shown, in the bellows pump 100A of the second embodiment, the coil spring 14 is positioned biased towards the shaft portion L12. It should be noted that the coil spring 14 may also be positioned biased towards the shaft portion R13. This bellows pump 100A, for example, has a protective structure in which the entire pump is covered by a cover 123 made of resin components or the like.

[0101] The displacement sensor 23a is, for example, mounted on the end of a shaft portion R13 of the connecting shaft 11a, on the side near the coil spring 14, while a detection plate 23b is mounted on the other shaft portion L12, also near the coil spring 14. The detection plate 23b is mounted, for example, on the end of the shaft portion L12 near the coil spring 14, such that its top end reaches the displacement sensor 23a when the coil spring 14 contracts.

[0102] In addition, liquid pressure sensors 116 and 117 are installed in the piping of the inlet 16 and the outlet 17 (neither shown). Furthermore, air pressure sensors 127a and 127b and leakage sensors 150a and 150b are installed at the bottom of cylinders 2a and 2b, facing the actuation chambers 6a and 6b. The detection outputs of each pressure sensor 116, 117 and 127a, 127b are input to the controller 25. The controller 25 also considers these detection outputs and switches solenoid valves L27a and R27b to achieve more suitable pump operation.

[0103] According to the second embodiment, since the coil springs 14 of each connecting shaft 11a, 11b are installed at an offset position, a structure that is unlikely to interfere with the piping of the pump's suction port 16 and discharge port 17 can be obtained. Thus, while achieving overall pump miniaturization, the flexibility of the piping can also be increased.

[0104] It should be noted that, as Figure 6 As shown, when solenoid valves L27a and R27b are in the ON state and air is introduced into actuation chambers 6a and 6b, suction valves 18a and 18b are closed, discharge valves 19a and 19b are open, and the conveying fluid is discharged from the two pump chambers 5a and 5b during the overlapping period, the coil spring 14 contracts as described above. Therefore, the top of the detection plate 23b on the shaft L12 side reaches the displacement sensor 23a on the shaft R13 side, and the contraction of the coil spring 14 is detected.

[0105] [Third Embodiment] Figure 7This is an explanatory diagram showing a portion of the structure of the double reciprocating pump according to the third embodiment of the present invention. It should be noted that... Figure 7 (a) shows the state of the coil spring 14 before it contracts. Figure 7 (b) shows the state of the coil spring 14 when it is contracted.

[0106] like Figure 7 As shown in (a), in the third embodiment, the shaft portion L12 connecting the shaft 11a is formed as a hollow shape having an internal space 12a. Furthermore, a rod-shaped detection body 23c, serving as a detected component, is fixed to the top end of the shaft portion R13, capable of moving in and out of the internal space 12a of the shaft portion L12. Additionally, a displacement sensor 23a is provided at a predetermined position on the shaft portion L12, facing the internal space 12a.

[0107] like Figure 7 As shown in (b), during the aforementioned overlap period OP, the coil spring 14 contracts, so the detection body 23c of the shaft R13 reaches the displacement sensor 23a within the internal space 12a of the shaft L12, detecting the contraction of the coil spring 14. According to the structure of the third embodiment, it is unnecessary to provide a detection plate 23b around the connecting shaft 11a, thus simplifying the structure around the connecting shaft 11a. It should be noted that, for example, a damping spring 14a, which enhances the contraction force during the contraction of the coil spring 14, can also be disposed inside the coil spring 14 of the connecting shaft 11a.

[0108] The foregoing has described several embodiments of the present invention, but these embodiments are merely illustrative and not intended to limit the scope of the invention. These novel embodiments can also be implemented in various other ways, with various omissions, substitutions, and modifications possible without departing from the spirit of the invention. These embodiments and their variations are all included within the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

[0109] For example, although the above embodiment employs a structure in which a coil spring 14, serving as a telescopic member, is provided on the connecting shafts 11a and 11b, this telescopic member can also be made of other elastomers. Furthermore, a damper can be provided together with the coil spring 14 or other elastomers as the telescopic member. The damper can mitigate the force exerted when the coil spring 14 extends from its self-contracted state, thus preventing excessive suction pressure from being generated on the suction side as energy stored in the coil spring 14 is released, and can be expected to suppress the increase in pulsation amplitude. Additionally, although the above embodiment exemplifies a double reciprocating pump using a pair of deformable bellows 3a and 3b as movable partition members, the present invention is also applicable to double reciprocating pumps using a pair of movable pistons as movable partition members.

[0110] Furthermore, although the above embodiment describes that the controller 25 drives a pair of bellows L3a and R3b based on judgment information that is based on the detection output and is used to indicate the presence, sequence, and time difference of the detection of the displacement sensor 23a and the proximity switches L21a and R21b, such that the judgment information indicates that the detection of the displacement sensor 23a and the proximity switches L21a and R21b occurs simultaneously, it is not limited to this. That is, since the judgment information is information indicating the presence, sequence, and time difference of the above detection, for example, an ON delay timer can be inserted into the digital detection signal (detection output) of either the displacement sensor 23a or the proximity switches L21a and R21b, so that a time difference is generated when the digital detection signal is input to the controller 25. In this scenario, although the detections by displacement sensor 23a and proximity switches L21a and R21b do not occur simultaneously, controller 25 only needs to drive bellows L3a and R3b in the same manner as if their detections were actually simultaneous, taking into account the set time difference of the ON delay timer. Alternatively, for example, the ON delay timer can be omitted, and a time difference can be created by changing the detection position of displacement sensor 23a, causing the digital detection signal to be input to controller 25. In this case, it is also only necessary to consider this time difference and drive bellows L3a and R3b in the same manner as if their detections were actually simultaneous.

Claims

1. A double reciprocating pump, comprising: The housing component has a pair of spaces formed axially inside it; A pair of movable partition components are respectively disposed in the pair of spaces in a deformable or movable manner along the axial direction, and divide the pair of spaces into a pump chamber and a working chamber respectively along the axial direction; A connecting shaft that connects the pair of movable partitions in an axially retractable manner via a telescopic component; A suction valve, which is located on the suction side of the pump chamber, introduces the conveying fluid into the pump chamber; A discharge valve is provided on the discharge side of the pump chamber to discharge the conveyed fluid from the pump chamber; A valve mechanism for introducing working fluid into the working chamber and discharging working fluid from the working chamber; A displacement sensor detects that the telescopic component of the connecting shaft has contracted; Proximity sensors detect when the pair of movable partitions reach the end of the moving stroke; as well as The controller, based on the outputs of the displacement sensor and the proximity sensor, drives the pair of movable partition components by switching the valve mechanism; Wherein, the controller: Based on the judgment information that is based on the output and represents the presence, sequence and time difference of the detection of the displacement sensor and the proximity sensor, the overlap period during which the compression steps of one pump chamber partially overlap with those of another pump chamber is determined, and the pair of movable partition components are driven in a manner that changes the judgment information according to the judgment result.

2. The double reciprocating pump as described in claim 1, wherein, The controller: Based on the judgment information, the overlap period is determined during each stroke of the deformation or movement of the pair of movable partition members, and Drive the pair of movable partition components so that the judgment information indicates that the detection by the displacement sensor and the proximity sensor occurs simultaneously.

3. The double reciprocating pump as described in claim 2, wherein, The controller: When the judgment information indicates that the detection of the proximity sensor occurs before the detection of the displacement sensor, or that there is a detection of the proximity sensor but no detection of the displacement sensor, it is determined that the start of the overlapping period is later, and the pair of movable partition components are driven in a manner that reduces the time difference between the start time of deformation or movement of the pair of movable partition components in each stroke by a fixed time, until the detection of the proximity sensor and the displacement sensor occurs simultaneously.

4. The double reciprocating pump as described in claim 2, wherein, The controller: When the judgment information indicates that the detection of the displacement sensor occurs before the detection of the proximity sensor, or that the displacement sensor detects but the proximity sensor does not, it is determined that the start of the overlapping period is earlier, and the pair of movable partitions are driven by increasing the time difference between the start time of deformation or movement of the pair of movable partitions in each stroke by a fixed time, until the detection of the displacement sensor and the proximity sensor occurs simultaneously.

5. The double reciprocating pump as described in any one of claims 1 to 4, wherein, The displacement sensor is disposed on one side of the connecting shaft, separated from the telescopic component, and detects the contraction of the telescopic component by detecting the detected component disposed on the other side of the shaft, separated from the telescopic component.

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