Twin reciprocating pump

Abstract

The twin reciprocating pump comprises a case member, a pair of movable partition members, a connecting shaft, a suction valve, a discharge valve, a valve mechanism, a displacement sensor that detects when the extension member of the connecting shaft has contracted, proximity sensors that detect when the pair of movable partition members have reached the end of their movement stroke, and a controller that drives the pair of movable partition members by switching the valve mechanism based on the outputs of the displacement sensor and proximity sensor. The controller determines the overlap period during which the compression process of one pump chamber and the other pump chamber partially overlaps based on judgment information indicating the presence or absence, order, and time difference of detections from the displacement sensor and proximity sensor based on the output, and drives the pair of movable partition members so that the judgment information changes according to the judgment result.

Description

Technical Field

[0001] The present invention relates to a double reciprocating pump.

Background Art

[0002] Conventionally, a pair of closed spaces are partitioned into a pump chamber and an operating chamber by a movable partition member such as a bellows connected to a connecting shaft, and the connecting shaft is reciprocated by alternately introducing a working fluid into the pair of operating chambers, so that the pump chamber is alternately compressed and expanded. A double reciprocating pump is known.

[0003] In a double reciprocating pump, at the end of the reciprocating movement stroke of the connecting shaft, a pair of suction valves and a pair of discharge valves are switched from one pump chamber side to the other pump chamber side, respectively. As a result, pulsation corresponding to the number of strokes occurs in the discharge flow rate. Such pulsation causes various problems in, for example, manufacturing process fields such as semiconductors, liquid crystals, solar cells, pharmaceuticals, and foods. Therefore, reducing pulsation has become a major issue to be improved.

[0004] In order to solve such problems, when driving a pair of movable partition members by switching a valve mechanism with a controller, the overlapping rate indicated by the ratio of the overlapping distance to the total stroke length of the movable partition member is controlled so that the compression process of one pump chamber and the compression process of the other pump chamber partially overlap, and a double reciprocating pump for reducing pulsation is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the double reciprocating pump disclosed in Patent Document 1, the displacement of a pair of movable partition members is continuously detected by two displacement sensors, and the optimal overlap ratio is set based on these outputs to reduce pulsation. This requires complex and delicate control, particularly in calculating and setting the overlap ratio. Therefore, there is a problem in that it is not envisioned that pulsation reduction can be achieved by reducing the number of sensors and performing simpler control with a simpler configuration.

[0007] This invention has been made in view of the above circumstances, and aims to provide a twin reciprocating pump that can reduce pulsation with a simple configuration and simple control. [Means for solving the problem]

[0008] The twin reciprocating pump according to the present invention comprises: a case member that forms a pair of spaces along the axial direction inside; a pair of movable partition members that are each axially deformable or movable within the pair of spaces and divide the pair of spaces into a pump chamber and an operating chamber in the axial direction; a connecting shaft that connects the pair of movable partition members so as to be axially expandable and contractible via an expandable member; a suction valve provided on the suction side of the pump chamber to guide the transfer fluid into the pump chamber; a discharge valve provided on the discharge side of the pump chamber to discharge the transfer fluid from the pump chamber; a valve mechanism for introducing working fluid into the operating chamber and discharging the working fluid from the operating chamber; a displacement sensor that detects when the expandable member of the connecting shaft has contracted; proximity sensors that each detect when the pair of movable partition members have reached the end of their movement stroke; and a controller that drives the pair of movable partition members by switching the valve mechanism based on the outputs of the displacement sensor and the proximity sensor. The controller determines the overlap period during which the compression processes of one pump chamber and the other pump chamber partially overlap, based on the determination information indicating the presence or absence, order, and time difference of detections by the displacement sensor and the proximity sensor based on the output, and drives the pair of movable partition members so that the determination information changes according to the determination result.

[0009] In one embodiment of the present invention, the controller determines the overlap period based on the determination information for each stroke of deformation or movement of the pair of movable partition members, and drives the pair of movable partition members such that the determination information indicates that the detection by the displacement sensor and the proximity sensor is simultaneous.

[0010] In another embodiment of the present invention, if the determination information indicates that the proximity sensor detects a displacement sensor before the displacement sensor detects a displacement sensor, or that the proximity sensor detects a displacement sensor but the displacement sensor does not, the controller determines that the start of the overlapping period is delayed and drives the pair of movable partition members so that the time difference in the start timing of deformation or movement of the pair of movable partition members decreases by a certain amount of time with each stroke until the proximity sensor and the displacement sensor detect a displacement sensor simultaneously.

[0011] In yet another embodiment of the present invention, if the determination information indicates that the displacement sensor has detected the displacement sensor before the proximity sensor has detected it, or that the displacement sensor has detected the displacement sensor but the proximity sensor has not, the controller determines that the overlap period has started earlier and drives the pair of movable partition members so that the time difference in the start timing of the deformation or movement of the pair of movable partition members increases by a certain amount of time with each stroke until the detection of the displacement sensor and the proximity sensor occurs simultaneously.

[0012] In yet another embodiment of the present invention, the displacement sensor is positioned on one shaft portion of the connecting shaft via the expandable member and detects the contraction of the expandable member by detecting a detected portion positioned on the other shaft portion via the expandable member. The expandable member is preferably a coil spring.

[0013] In yet another embodiment of the present invention, the valve mechanism includes a pair of valves provided in each of the pair of working chambers, and a pair of regulators that adjust the pressure of the working fluid from a working fluid supply source and supply the working fluid to each of the pair of valves.

[0014] Another double reciprocating pump according to the present invention comprises a pump head, a pair of bottomed cylindrical bellows attached to both sides of the pump head with their openings facing each other and each forming a pump chamber inside, and each being expandable and contractible in the axial direction, a pair of bottomed cylindrical cylinders mounted on the pump head with their openings facing each other, arranged coaxially with respect to the bellows to house the pair of bellows inside each, and forming an operating chamber between the pair of bellows, a pair of pump shafts that airtightly and slidably penetrate the bottoms of the pair of cylinders along the central axis of the cylinders, with one end of each shaft connected to the bottom of the pair of bellows, and the pair of pump shafts The pump comprises a connecting shaft that connects the other ends of two pump shafts so as to be axially expandable and contractible via an expandable member; a valve unit mounted on the pump head inside the pump chamber that guides the transfer fluid from the suction port to the pump chamber and from the pump chamber to the discharge port; a valve mechanism for introducing working fluid into the working chamber and discharging the working fluid from the working chamber; a displacement sensor that detects when the expandable member of the connecting shaft has contracted; proximity sensors that each detect when the pair of bellows have reached their 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 determines the overlap period in which the compression process of one pump chamber and the other pump chamber partially overlaps based on determination information indicating the presence or absence, order and time difference of detections by the displacement sensor and the proximity sensor based on the output, and drives the pair of bellows so that the determination information changes according to the determination result.

[0015] In one embodiment of the present invention, the controller determines the overlap period based on the determination information for each stroke of the extension and contraction of the pair of bellows, and drives the pair of bellows such that the determination information indicates that the displacement sensor and the proximity sensor are detecting each other simultaneously.

[0016] In another embodiment of the present invention, if the determination information indicates that the proximity sensor detects a displacement sensor before the displacement sensor detects a displacement sensor, or that the proximity sensor detects a displacement sensor but the displacement sensor does not, the controller determines that the start of the overlapping period is delayed and drives the pair of bellows so that the time difference in the start timing of the contraction of the pair of bellows decreases by a certain amount of time with each stroke until the detection of the proximity sensor and the displacement sensor occurs simultaneously.

[0017] In yet another embodiment of the present invention, if the determination information indicates that the displacement sensor detects a value before the proximity sensor detects a value, or that the displacement sensor detects a value but the proximity sensor does not, the controller determines that the overlap period has started earlier and drives the pair of bellows so that the time difference in the start timing of the contraction of the pair of bellows increases by a certain amount of time with each stroke until the detection of the displacement sensor and the proximity sensor occurs simultaneously. [Effects of the Invention]

[0018] According to the present invention, pulsation can be reduced by performing simple control with a simple configuration. [Brief explanation of the drawing]

[0019] [Figure 1] This is an explanatory diagram showing the schematic configuration of a double reciprocating pump according to the first embodiment of the present invention. [Figure 2] This is a time chart showing the proper operation of the twin reciprocating pump. [Figure 3] This is a time chart showing an example of the control operation of the twin reciprocating pump. [Figure 4] This is a time chart showing another example of the control operation of the same twin reciprocating pump. [Figure 5] This is an explanatory diagram showing the schematic configuration of a twin reciprocating pump according to a second embodiment of the present invention. [Figure 6] This is an explanatory diagram showing the schematic configuration of the twin reciprocating pump. [Figure 7]It is an explanatory drawing showing a partial configuration of a double reciprocating pump according to a third embodiment of the present invention.

Mode for Carrying Out the Invention

[0020] Hereinafter, with reference to the accompanying drawings, a double reciprocating pump according to an embodiment of the present invention will be described in detail. However, the following embodiments do not limit the invention according to each claim, and not all combinations of the features described in the embodiments are essential for the solution means of the invention. Also, in the following embodiments, the same or corresponding components are denoted by the same reference numerals, and duplicate descriptions are omitted. Further, in the embodiments, when the arrangement, scale, dimensions, etc. of each component are exaggerated or diminished and shown in a state that does not match the actual one, and when the description of some components is omitted and shown, there are such cases.

[0021] [First Embodiment] [Configuration of Double Reciprocating Pump] FIG. 1 is an explanatory drawing showing a schematic configuration of a double reciprocating pump according to an embodiment of the present invention, and shows, for example, a cross section of a double reciprocating bellows pump and its peripheral mechanism. Note that since FIG. 1 shows a cross section and the like of the double reciprocating bellows pump as viewed from the front, the left and right along the paper surface of FIG. 1 mean the left and right directions and the axial direction of the double reciprocating bellows pump, and the direction along the paper surface orthogonal to this left and right direction means the up and down direction. [[ID=​​​​​Inside cylinders 2a and 2b, a pair of axially aligned spaces (internal spaces) are formed. Within the pair of internal spaces, bellows L3a and R3b, which are expandable and contractible (deformable or movable) in the axial direction, are coaxially arranged. Bellows L3a and R3b are formed as a pair of movable partition members in the shape of bottomed cylinders, and their open ends are fixed to the pump head 1.

[0024] Shaft fixing plates 4a and 4b are fixed to the bottom of bellows L3a and R3b, respectively. These bellows L3a and R3b constitute movable partition members that divide the pair of internal spaces of cylinders 2a and 2b in the axial direction, with the inside forming pump chambers 5a and 5b and the outside forming working chambers 6a and 6b, respectively.

[0025] One end of the coaxially extending shafts 7a and 7b is fixed to the shaft fixing plates 4a and 4b, respectively. The shafts 7a and 7b constitute a pair of pump shafts. The shafts 7a and 7b each pass through the center of the bottom of the cylinders 2a and 2b along their central axis, via a sealing member 8, in an airtight and slidable manner, and extend to the outside. The other ends of the shafts 7a and 7b are fixed to the connecting plates 9a and 9b, respectively, by nuts 10.

[0026] The connecting plates 9a and 9b are connected to the cylinders 2a and 2b at their upper and lower positions by connecting shafts 11a and 11b, respectively. Each of the upper and lower connecting shafts 11a and 11b consists of a rod-shaped shaft portion L12 and shaft portion R13, and a coil spring 14, which is an expandable / contractible member, mounted between these shaft portions L12 and R13.

[0027] Each connecting shaft 11a, 11b has its shaft portion L12 and shaft portion R13 opposite the coil spring 14 side bolted and fixed to the connecting plates 9a, 9b by bolts 15. Thus, each connecting shaft 11a, 11b connects a pair of bellows 3a, 3b, which are indirectly connected via the connecting plates 9a, 9b, shafts 7a, 7b, and shaft fixing plates 4a, 4b, to the coil spring 14 so that they can extend and retract in the axial direction.

[0028] On the other hand, the pump head 1 is provided with, for example, a suction port 16 and a discharge port 17 for the fluid to be transferred, located on the side of the pump. The suction port 16 and the discharge port 17 are positioned offset in the circumferential direction from the position where the connecting shafts 11a and 11b are located, relative to the cylinders 2a and 2b. Furthermore, as a valve unit, suction valves 18a and 18b are provided at positions leading from the suction port 16, which is the suction side of the pump head 1, to the pump chambers 5a and 5b. In addition, discharge valves 19a and 19b are provided in the pathway leading from the pump chambers 5a and 5b of the pump head 1 to the discharge port 17, which is the discharge side.

[0029] Furthermore, proximity switches (SW) L21a and R21b, which serve as proximity sensors, are mounted on the bottom outer walls of cylinders 2a and 2b. Proximity switches L21a and R21b detect when the connecting plates 9a and 9b are closest together (when bellows L3a and R3b are most contracted (contracted end)), respectively.

[0030] Furthermore, of the two connecting shafts 11a and 11b, for example, the upper connecting shaft 11a is equipped with a displacement sensor 23a. The displacement sensor 23a is provided, for example, at the end of the shaft portion L12 of the connecting shaft 11a on the coil spring 14 side. The displacement sensor 23a detects when the coil spring 14 of the connecting shaft 11a has contracted (collapsed).

[0031] The displacement sensor 23a can be configured as, for example, a photomicrosensor, proximity sensor, photoelectric sensor, fiber sensor, ultrasonic sensor, and physical contact switches such as microswitches and limit switches. In this embodiment, the displacement sensor 23a is configured as a photomicrosensor.

[0032] In this case, as described above, the displacement sensor 23a is located on one shaft portion L12 via the coil spring 14 of the connecting shaft 11a, and the detection plate 23b, which is the part to be detected, is attached to the other shaft portion R13 via the coil spring 14. The base end of the detection plate 23b is attached, for example, to the end of the shaft portion R13 on the coil spring 14 side, so that the tip of the detection plate 23b reaches the displacement sensor 23a when the coil spring 14 is compressed.

[0033] The displacement sensor 23a detects the contraction of the coil spring 14 by detecting the tip of the detection plate 23b. In other words, it detects that the discharge from the pump chambers 5a and 5b is covering it. The displacement sensor 23a and the detection plate 23b may be arranged on the shaft portion L12 and shaft portion R13 in opposite positions, respectively. In this example, the displacement sensor 23a and the detection plate 23b are located above the connecting shaft 11a, but they may also be located to the side or below the connecting shaft 11a, for example. In this example, the displacement sensor 23a and the detection plate 23b are located on the shaft portion L12 and shaft portion R13 above the bellows pump 100, but they may also be located on the shaft portion L12 and shaft portion R13 below the bellows pump 100.

[0034] Digital detection signals (detection outputs) from proximity switches L21a and R21b, and displacement sensor 23a are input to controller 25. The working fluid, such as air, from a working fluid supply source (not shown), such as an air compressor, is restricted to a predetermined pressure by a pair of regulators L26a and R26b, and supplied to a pair of valves, solenoid valves L27a and R27b. The valve mechanism includes these regulators L26a and R26b, and solenoid valves L27a and R27b.

[0035] Solenoid valves L27a and R27b introduce air into the working chambers 6a and 6b and discharge air from the working 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. In this way, controller 25 switches solenoid valves L27a and R27b to drive a pair of bellows L3a and R3b.

[0036] Specifically, the controller 25 determines the overlap period during which the compression processes of one pump chamber 5a (or 5b) and the other pump chamber 5b (or 5a) partially overlap, based on judgment information indicating the presence or absence of detection, the order, and the time difference of detections from the displacement sensor 23a and proximity switches L21a and R21b based on the above-mentioned detection output. Then, the controller 25 drives the pair of bellows L3a and R3b so that the judgment information, i.e., the presence or absence of detection, the order, and the time difference, changes according to the judgment result.

[0037] The controller 25 determines the overlap period based on the judgment information for each stroke of expansion and contraction of the pair of bellows L3a and bellows R3b. The controller 25 then drives the pair of bellows L3a and bellows R3b so that the judgment information indicates that the displacement sensor 23a and proximity switches L21a and R21b are detecting simultaneously.

[0038] [Pump operation] Next, the operation of the twin reciprocating bellows pump of this embodiment, configured as described above, will be explained. Figure 2 is a time chart showing the proper operation of a twin reciprocating pump. As described above, the air from the working fluid source is limited to a predetermined pressure by regulators L26a and R26b, respectively, before being supplied to solenoid valves L27a and R27b.

[0039] Therefore, pressure fluctuations in one working chamber 6a (or 6b) do not affect the pressure in the other working chamber 6b (or 6a), resulting in a pulsation reduction effect. Note that the regulator is not limited to two as described above; it may be configured with just one. In this case, it is more desirable to use a so-called precision regulator.

[0040] Here, in the bellows pump 100, for example, let's assume that solenoid valve L27a is in the exhaust state (off state), solenoid valve R27b is in the supply state (on state), pump chamber 5a is in the extension (expansion) phase, and pump chamber 5b is in the contraction phase. At this time, the suction valve 18a and discharge valve 19b are open, and the suction valve 18b and discharge valve 19a are closed. Therefore, the fluid to be transferred is introduced into pump chamber 5a from the suction port 16 and discharged from pump chamber 5b through the discharge port 17.

[0041] On the other hand, let's assume that solenoid valve L27a is in the supply air state (on state) and solenoid valve R27b is in the exhaust state (off state), with pump chamber 5a in the contraction phase and pump chamber 5b in the extension phase. In this case, the suction valve 18a and discharge valve 19b are closed, and the suction valve 18b and discharge valve 19a are open. Therefore, the transfer fluid is introduced into pump chamber 5b from the suction port 16 and discharged from pump chamber 5a through the discharge port 17.

[0042] Furthermore, in order to reduce pulsation, solenoid valves L27a and R27b are switched to provide an overlapping period, for example, when pump chamber 5a switches from the extension process to the compression process, pump chamber 5b maintains the compression process, and when pump chamber 5b switches from the extension process to the compression process, pump chamber 5a maintains the compression process. In other words, the timing of when the discharge from pump chambers 5a and 5b begins to overlap is appropriate.

[0043] During this overlapping period, with solenoid valves L27a and R27b ON, air is introduced into the working chambers 6a and 6b, so the suction valves 18a and 18b are closed and the discharge valves 19a and 19b are open, and the transfer fluid is discharged from both pump chambers 5a and 5b. In other words, when both bellows L3a and R3b are contracted, the coil springs 14 of the connecting shafts 11a and 11b are compressed and contract (collapse) to absorb the dimensional change between the ends of bellows L3a and R3b.

[0044] Under the control of the controller 25, after the solenoid valve L27a switches from the exhaust state to the supply state (contraction process of bellows L3a), the solenoid valve R27b switches from the exhaust state to the supply state (contraction process of bellows R3b) when time T1 seconds have elapsed. Subsequently, after the overlap period OP has elapsed and the proximity switch L21a detects the stroke end (contraction end of bellows 3a), the displacement sensor 23a also turns on at the same time during proper operation. This causes the solenoid valve L27a to switch from the supply state to the exhaust state.

[0045] Similarly, under the control of the controller 25, after the solenoid valve R27b switches from the exhaust state to the supply state (contraction process of bellows R3b), the solenoid valve L27a switches from the exhaust state to the supply state (contraction process of bellows L3a) after a time T2 seconds has elapsed. Subsequently, after the overlap period OP has elapsed and the proximity switch R21b detects the stroke end (contraction end of bellows 3b), the displacement sensor 23a also turns on at the same time during proper operation. This causes the solenoid valve R27b to switch from the supply state to the exhaust state. By repeating this operation in the left and right pump chambers 5a and 5b, the bellows pump 100 can perform proper operation with reduced pulsation.

[0046] Figure 2 shows the overlapping period OP during which both the left and right pump chambers 5a and 5b are in the compression process, appropriately illustrating this for each stroke of bellows L3a and bellows R3b. In this case, it can be seen that the alternating detection (on) of proximity switches L21a and R21b and the detection (on) of displacement sensor 23a occur simultaneously. This indicates that bellows L3a and R3b have completed their full stroke to the contraction end (end of discharge), and that pulsation has been reduced.

[0047] As described above, during proper operation, the time difference between the start of discharge from bellows L3a (when solenoid valve L27a switches from exhaust to supply air) and the start of discharge from bellows R3b (when solenoid valve R27b switches from exhaust to supply air) is T1 seconds. Furthermore, the time difference between the start of discharge from bellows R3b (when solenoid valve R27b switches from exhaust to supply air) and the start of discharge from bellows L3a (when solenoid valve L27a switches from exhaust to supply air) is T2 seconds. Thus, during proper pump operation with reduced pulsation, the pair of bellows L3a and bellows R3b maintain constant time differences T1 and T2 seconds, respectively, for when they begin overlapping discharges, while performing a full stroke so that an overlapping period OP of the same interval occurs with each stroke.

[0048] This can be understood by observing that when the time differences T1 and T2 are constant and appropriate, the alternating detection of proximity switches L21a and R21b and the detection of displacement sensor 23a occur simultaneously. Therefore, the controller 25 can be controlled to perform appropriate operations based on judgment information from sensors 21a, 21b, and 23a, even in response to fluctuations in the pump's operating conditions (air / liquid piping conditions, supply air pressure, discharge load, etc.).

[0049] Even if the pair of bellows L3a and R3b are not in full stroke, pulsation can be suppressed if the coil spring 14 is compressed. However, in this case, the solenoid valves L27a and R27b will repeatedly perform unnecessary intake and exhaust, leading to increased energy consumption due to increased air consumption and a reduced lifespan for the solenoid valves L27a and R27b. Therefore, they should be made to full stroke whenever possible. The proximity switches L21a and R21b are necessary to prevent such problems.

[0050] Figure 3 is a time chart showing an example of the control operation of a twin reciprocating pump. Figure 4 is a time chart showing another example of the control operation of a twin reciprocating pump. Figure 3 shows the control operation when the timing of starting to overlap the discharge is late, and Figure 4 shows the control operation when the timing of starting to overlap the discharge is early.

[0051] As shown in Figure 3, the controller 25 determines that the start of the overlapping period OP is delayed, that is, the timing of starting the discharge is delayed, if the judgment information indicates that the proximity switches L21a and R21b are detected before the displacement sensor 23a is detected, or that the proximity switches L21a and R21b are detected but the displacement sensor 23a is not. In this case, it is determined that the bellows L3a and R3b have reached their full stroke to the contracted end (discharge end) and that the pulsation has not been reduced.

[0052] Therefore, the controller 25 drives the pair of bellows L3a and R3b so that the time difference T1 seconds and T2 seconds of the start timing of the contraction (discharge) of the pair of bellows L3a and R3b decreases by a certain time (Δt) with each stroke until the (alternating) detection of proximity switches L21a and R21b and the detection of displacement sensor 23a occur simultaneously.

[0053] First, let's describe the operation pattern (A) in which bellows R3b starts discharging after bellows L3a has started discharging. In this operation pattern (A), when bellows L3a starts discharging and bellows R3b starts discharging after a time difference T1 seconds, solenoid valve L27a starts supplying air at the timing when bellows L3a starts discharging. At this time, bellows R3b is at its contracted end (discharging end) and proximity switch R21b is turned on, but since the coil springs 14 of connecting shafts 11a and 11b have not contracted, displacement sensor 23a is off.

[0054] Then, at the start of discharge from bellows R3b after T1 seconds, solenoid valve R27b starts supplying air. At this time, bellows L3a is at its contracted end (discharge ends) and proximity switch L21a turns on, but since the coil springs 14 of connecting shafts 11a and 11b have not contracted, displacement sensor 23a remains off. Therefore, controller 25 changes the discharge start timing so that the time difference becomes T1' (T1' = T1 - Δt) seconds, which is the time difference T1 seconds minus a certain time (Δt).

[0055] Next, if bellows L3a starts discharging, and bellows R3b starts discharging after a time difference T1' seconds, then solenoid valve L27a starts supplying air at the timing when bellows L3a starts discharging. At this time, solenoid valve R27b is supplying air and bellows R3b is in the contraction process, and after a short overlap period OP, bellows R3b reaches the contraction end (discharging ends) and proximity switch R21b turns on, but displacement sensor 23a remains off.

[0056] Then, at the start of discharge from bellows R3b after T1' seconds, solenoid valve R27b starts supplying air. At this time, solenoid valve L27a is supplying air and bellows L3a is in the contraction process, and after the overlap period OP has increased compared to the previous one, bellows L3a reaches the contraction end (end of discharge) and proximity switch L21a turns on, but displacement sensor 23a turns on with a delay. That is, proximity switch L21a turns on before displacement sensor 23a. Therefore, the discharge start timing is changed so that the time difference becomes T1'' (T1'' = T1' - Δt) seconds, which is the time difference T1' seconds minus a certain time (Δt).

[0057] Next, if bellows L3a starts discharging, and bellows R3b starts discharging after a time difference of T1'' seconds, then solenoid valve L27a starts supplying air at the timing when bellows L3a starts discharging. At this time, solenoid valve R27b is supplying air and bellows R3b is in the contraction process, and after an overlap period OP occurs similar to that after T1' seconds, bellows R3b reaches the contraction end (discharging ends) and proximity switch R21b turns on, but displacement sensor 23a turns on with a slight delay. That is, proximity switch R21b turns on before displacement sensor 23a.

[0058] Then, at the start of discharge from bellows R3b after T1'' seconds, solenoid valve R27b starts supplying air. At this time, solenoid valve L27a is supplying air and bellows L3a is in the contraction process, and after the overlap period OP increases compared to that after T1' seconds, bellows L3a reaches the contraction end (end of discharge) and proximity switch L21a and displacement sensor 23a are turned on simultaneously.

[0059] In this case, the controller 25 determines that the bellows L3a and R3b have reached their full stroke and that the pulsation has been reduced, indicating proper operation. From this point onward, it repeats the switching of solenoid valves L27a and R27b without changing the time difference T1'' seconds. The example shown in Figure 3 illustrates a case where the timing for starting the discharge from pump chambers 5a and 5b is appropriate, achieved by subtracting a fixed time (Δt) from the time difference T1 seconds for each stroke, and repeating this process twice.

[0060] On the other hand, let's describe the operation pattern (B) in which bellows L3a starts discharging after bellows R3b has started discharging. In this operation pattern (B), when bellows R3b starts discharging and bellows L3a starts discharging after a time difference T2 seconds, solenoid valve R27b starts supplying air at the timing when bellows R3b starts discharging. At this time, bellows L3a is at its contracted end (discharging end) and proximity switch L21a is turned on, but since the coil springs 14 of connecting shafts 11a and 11b have not contracted, displacement sensor 23a is off.

[0061] Then, at the start of discharge from bellows L3a after T2 seconds, solenoid valve L27a starts supplying air. At this time, solenoid valve R27b is supplying air and bellows R3b is in the contraction process, and after a short overlap period OP, bellows R3b reaches the contraction end (end of discharge) and proximity switch R21b turns on, but displacement sensor 23a is off. Therefore, the discharge start timing is changed so that the time difference becomes T2' (T2' = T2 - Δt) seconds, which is the time difference T2 seconds minus a certain time (Δt).

[0062] Next, if bellows R3b starts discharging, and bellows L3a starts discharging after a time difference of T2' seconds, then solenoid valve R27b starts supplying air at the timing when bellows R3b starts discharging. At this time, solenoid valve L27a is supplying air and bellows L3a is in the contraction process, and after the overlap period OP has increased compared to the one after T2 seconds, bellows L3a reaches the contraction end (discharging ends) and proximity switch L21a turns on, but displacement sensor 23a turns on with a delay. That is, proximity switch L21a turns on before displacement sensor 23a.

[0063] Then, at the start of discharge from bellows L3a after T2' seconds, solenoid valve L27a starts supplying air. At this time, solenoid valve R27b is supplying air and bellows R3b is in the contraction process, and after the overlap period OP occurs as before, bellows R3b reaches the contraction end (end of discharge) and proximity switch R21b turns on, but displacement sensor 23a turns on with a slight delay. That is, proximity switch R21b still turns on before displacement sensor 23a. Therefore, the discharge start timing is changed so that the time difference becomes T2'' (T2'' = T2' - Δt) seconds, which is the time difference T2' seconds minus a certain time (Δt).

[0064] Next, if bellows R3b starts discharging, and bellows L3a starts discharging after a time difference of T2'' seconds, then solenoid valve R27b starts supplying air at the timing when bellows R3b starts discharging. At this time, solenoid valve L27a is supplying air and bellows L3a is in the contraction process, and after the overlap period OP has increased compared to that after T2' seconds, bellows L3a reaches the contraction end (discharging ends) and proximity switch L21a and displacement sensor 23a are turned on simultaneously.

[0065] Then, at the start of discharge from bellows L3a after T2'' seconds, solenoid valve L27a starts supplying air. At this time, solenoid valve R27b is supplying air and bellows R3b is in the contraction process, and after the overlap period OP occurs as before, bellows R3b reaches the contraction end (end of discharge) and proximity switch R21b and displacement sensor 23a are turned on simultaneously.

[0066] In this case, the controller 25 determines that the bellows R3b and L3a have reached their full stroke and that the pulsation has been reduced, indicating proper operation. From this point onward, it repeatedly switches between the solenoid valves R27b and L27a without changing the time difference T2'' seconds. The example shown in Figure 3 illustrates a case where the timing for starting the discharge from the pump chambers 5b and 5a is appropriate, achieved by subtracting a fixed time (Δt) from the time difference T2 seconds for each stroke, and repeating this process twice.

[0067] In this manner, if the bellows pump 100 is late in starting to discharge from bellows L3a and bellows R3b, it alternately repeats the operation of the above operation pattern (A) and operation pattern (B) with each stroke until the detection of proximity switches L21a and R21b and the detection of displacement sensor 23a occur simultaneously, thereby changing the start timing so that the time difference T1 seconds and T2 seconds of the discharge start timing decreases by a constant time (Δt) with each stroke.

[0068] As a result, even in situations where the timing of starting discharge is delayed due to fluctuations in the pump's operating conditions as described above, the pump can be operated by automatically adjusting the decision information (for example, changing the start timing) based on the detection output from each sensor 21a, 21b, and 23a to ensure proper operation that reduces pulsation.

[0069] On the other hand, as shown in Figure 4, if the controller 25 determines that the overlap period OP starts early, that is, the timing for starting the discharge overlap is early, if the judgment information indicates that the displacement sensor 23a detects the displacement before the proximity switches L21a and R21b, or that the displacement sensor 23a detects the displacement but the proximity switches L21a and R21b do not. In this case, although the pulsation is reduced, it is understood that the bellows L3a and R3b have not reached their full stroke to the contracted end (discharge end).

[0070] Therefore, the controller 25 drives the pair of bellows L3a and R3b so that the time difference T1 seconds and T2 seconds of the start timing of the contraction (discharge) of the pair of bellows L3a and R3b increases by a constant time (Δt) with each stroke until the detection of the displacement sensor 23a and the (alternating) detection of the proximity switches L21a and R21b occur simultaneously.

[0071] First, let's describe the operation pattern (C) in which bellows R3b starts discharging after bellows L3a has started discharging. In this operation pattern (C), when bellows L3a starts discharging and bellows R3b starts discharging after a time difference T1 seconds, solenoid valve L27a starts supplying air at the timing when bellows L3a starts discharging. At this time, since bellows R3b is in the contraction process, an overlap period OP occurs and solenoid valve R27b starts exhausting before it has reached its contraction end. For this reason, proximity switch R21b remains off, and since the coil springs 14 of connecting shafts 11a and 11b are contracted, displacement sensor 23a turns on.

[0072] Then, at the start of discharge from bellows R3b after T1 seconds, solenoid valve R27b starts supplying air. At this time, since bellows L3a is in the contraction process, a similar overlap period OP occurs, and solenoid valve L27a starts exhausting before reaching the contraction end. Therefore, proximity switch L21a remains off, and since the coil springs 14 of connecting shafts 11a and 11b are contracted, displacement sensor 23a turns on. Accordingly, the discharge start timing is changed so that the time difference becomes T1' (T1' = T1 + Δt) seconds, which is the time difference T1 seconds plus a constant time (Δt).

[0073] Next, if bellows L3a starts discharging, and bellows R3b starts discharging after a time difference T1' seconds, then solenoid valve L27a starts supplying air at the timing when bellows L3a starts discharging. At this time, since bellows R3b is in the contraction process, a similar overlap period OP occurs, and solenoid valve R27b starts exhausting before it has reached its contraction end. For this reason, proximity switch R21b remains off, and displacement sensor 23a turns on.

[0074] Then, at the start of discharge from bellows R3b after T1' seconds, solenoid valve R27b starts supplying air. At this time, since bellows L3a is in the contraction process, a similar overlap period OP occurs, and solenoid valve L27a starts exhausting air before it has reached its contraction end. For this reason, proximity switch L21a remains off, and displacement sensor 23a turns on. Therefore, the discharge start timing is changed so that the time difference becomes T1'' (T1'' = T1' + Δt) seconds, which is the time difference T1' seconds plus a constant time (Δt).

[0075] Next, if bellows L3a starts discharging, and bellows R3b starts discharging after a time difference T1'' seconds, then solenoid valve L27a starts supplying air at the timing when bellows L3a starts discharging. At this time, since bellows R3b is in the contraction process, a similar overlapping period OP occurs, and solenoid valve R27b starts exhausting just before it reaches the contraction end. For this reason, proximity switch R21b remains off, and displacement sensor 23a turns on.

[0076] Then, at the start of discharge from bellows R3b after T1'' seconds, solenoid valve R27b starts supplying air. At this time, since bellows L3a is in the contraction process, an overlapping period OP occurs, and after reaching the contraction end (end of discharge), proximity switch L21a and displacement sensor 23a are turned on simultaneously.

[0077] In this case, the controller 25 determines that the pulsation has been reduced and that the bellows L3a is in full stroke, indicating proper operation. From this point onward, it repeatedly switches between solenoid valves L27a and R27b without changing the time difference T1'' seconds. The example shown in Figure 4 illustrates a case where the timing for starting the discharge from pump chambers 5a and 5b is appropriate, achieved by adding a fixed time (Δt) to the time difference T1 seconds for each stroke, and repeating this process twice.

[0078] On the other hand, let's describe the operation pattern (D) in which bellows L3a starts discharging after bellows R3b has started discharging. In this operation pattern (D), when bellows R3b starts discharging and bellows L3a starts discharging after a time difference T2 seconds, solenoid valve R27b starts supplying air at the timing when bellows R3b starts discharging. At this time, since bellows L3a is in the contraction process, after an overlap period OP occurs as described above, solenoid valve L27a starts exhausting before it has reached the contraction end. For this reason, proximity switch L21a remains off, and since the coil springs 14 of connecting shafts 11a and 11b are contracted, displacement sensor 23a turns on.

[0079] Then, at the start of discharge from bellows L3a after T2 seconds, solenoid valve L27a starts supplying air. At this time, since bellows R3b is in the contraction process, a similar overlap period OP occurs, and solenoid valve R27b starts exhausting air before it reaches the contraction end. For this reason, proximity switch R21b remains off, and displacement sensor 23a turns on. Therefore, the discharge start timing is changed so that the time difference becomes T2' (T2' = T2 + Δt) seconds, which is the time difference T2 seconds plus a constant time (Δt).

[0080] Next, if bellows R3b starts discharging, and bellows L3a starts discharging after a time difference T2' seconds, then solenoid valve R27b starts supplying air at the timing when bellows R3b starts discharging. At this time, since bellows L3a is in the contraction process, a similar overlap period OP occurs, and solenoid valve L27a starts exhausting before it has reached its contraction end. For this reason, proximity switch L21a remains off, and displacement sensor 23a turns on.

[0081] Then, at the start of discharge from bellows L3a after T2' seconds, solenoid valve L27a starts supplying air. At this time, since bellows R3b is in the contraction process, a similar overlapping period OP occurs, and solenoid valve R27b starts exhausting air just before it reaches the end of contraction. For this reason, proximity switch R21b remains off, and displacement sensor 23a turns on. Therefore, the discharge start timing is changed so that the time difference becomes T2'' (T2'' = T2' + Δt) seconds, which is the time difference T2' seconds plus a constant time (Δt).

[0082] Next, if bellows R3b starts discharging, and bellows L3a starts discharging after a time difference T2'' seconds, then solenoid valve R27b starts supplying air at the timing when bellows R3b starts discharging. At this time, since bellows L3a is in the contraction process, an overlapping period OP occurs, and then it reaches the contraction end (end of discharge), causing proximity switch L21a and displacement sensor 23a to turn on simultaneously.

[0083] Then, at the start of discharge from bellows L3a after T2'' seconds, solenoid valve L27a starts supplying air. At this time, bellows R3b is in the contraction process, so similarly, after an overlapping period OP occurs, it reaches the contraction end (end of discharge), and proximity switch R21b and displacement sensor 23a are turned on simultaneously.

[0084] In this case, the controller 25 determines that the pulsation has been reduced and that the bellows R3b is in full stroke, indicating proper operation. From this point onward, it repeatedly switches between solenoid valves R27b and L27a without changing the time difference T2'' seconds. The example shown in Figure 4 illustrates a case where the timing for starting the discharge from pump chambers 5b and 5a is appropriate, achieved by adding a fixed time (Δt) to the time difference T2 seconds for each stroke, and repeating this process twice.

[0085] In this manner, if the bellows pump 100 starts discharging from bellows L3a and bellows R3b too early, it alternately repeats the operation of operation pattern (C) and operation pattern (D) described above with each stroke until the detection by the displacement sensor 23a and the proximity switches L21a and R21b occur simultaneously, thereby changing the start timing so that the time difference T1 seconds and T2 seconds of the discharge start timing increases by a constant time (Δt) with each stroke.

[0086] As a result, even in situations where the timing of starting discharge is earlier due to fluctuations in the pump's operating conditions as described above, the system can automatically adjust the decision information (e.g., the discharge start timing) based on the detection output from each sensor 21a, 21b, and 23a to perform appropriate operation that reduces pulsation (e.g., by changing the start timing), thereby enabling the pump to operate.

[0087] Furthermore, compared to conventional double-reciprocating pumps, the bellows pump 100 of this embodiment can use a single displacement sensor 23a that outputs a digital detection signal, instead of multiple displacement sensors that output analog detection signals. As a result, an A / D converter is not required in the controller 25, making it possible to operate with a processor with low processing power, and enabling circuit simplification, circuit board size reduction, power consumption reduction, noise reduction, etc., thereby reducing overall costs.

[0088] Furthermore, conventional twin reciprocating pumps use two laser displacement sensors as displacement sensors. However, in locations where the ambient temperature around the pump is high, or where it is exposed to flammable gases, vapors, dust, etc., the laser may not be able to oscillate unless it is forcibly cooled by air purging or other means, or explosion-proof specifications may be required, which could result in measurement failure or render the pump unusable. For example, when using a pump in wafer cleaning equipment, cleaning fluids at temperatures up to approximately 180°C may be transferred as the transfer fluid, or solvents such as IPA may be transferred, so cooling equipment, energy consumption, or explosion-proof specifications are required to handle high temperatures.

[0089] In contrast, the bellows pump 100 can use a proximity sensor or the like as the displacement sensor 23a, which is more resistant to high-temperature environments and also has explosion-proof specifications than a laser displacement sensor. Therefore, even in locations where the ambient temperature around the pump is high, or in explosion-proof environments, the contraction of the coil spring 14 can be suitably measured without the need for cooling.

[0090] Furthermore, sensors that output analog detection signals, such as laser displacement sensors, are generally more expensive, larger, and require more wiring than sensors that output digital detection signals, such as photomicro sensors. For example, each laser displacement sensor requires at least four wires (two power lines and two signal lines). As a result, while a conventional double reciprocating pump requires a total of 14 wires, the bellows pump 100 does not require a laser displacement sensor, and the number of sensors themselves can be reduced, so it only requires a total of nine wires. This reduces costs and wiring effort, lowers the risk of sensor damage or malfunction due to miswiring, and allows for a reduction in pump size.

[0091] [Second Embodiment] Figures 5 and 6 are explanatory diagrams showing a schematic configuration of a twin reciprocating pump according to a second embodiment of the present invention. In the bellows pump 100 of the first embodiment, each connecting shaft 11a, 11b was equipped with a coil spring 14 mounted approximately midway between the shaft portion L12 and the shaft portion R13. However, as shown in Figure 5, in the bellows pump 100A of the second embodiment, the coil spring 14 is positioned biased toward the shaft portion L12 side. The coil spring 14 may also be positioned biased toward the shaft portion R13 side. This bellows pump 100A has a protective structure in which the pump as a whole is covered by a cover 123 made of a resin material or the like.

[0092] The displacement sensor 23a is attached, for example, to the end of one shaft portion R13 on the coil spring 14 side of the connecting shaft 11a via the coil spring 14, and the detection plate 23b is attached to the other shaft portion L12 via the coil spring 14. The base end of the detection plate 23b is attached, for example, to the end of shaft portion L12 on the coil spring 14 side, so that the tip of the detection plate 23b reaches the displacement sensor 23a when the coil spring 14 is compressed.

[0093] Furthermore, liquid pressure sensors 116 and 117 are provided in the piping of the suction port 16 and the piping of the discharge port 17 (neither of which are shown). In addition, air pressure sensors 127a and 127b and leak sensors 150a and 150b are provided at the bottom of the cylinders 2a and 2b, facing the working chambers 6a and 6b. The detection outputs of each pressure sensor 116, 117 and 127a and 127b are input to the controller 25. The controller 25 takes these detection outputs into consideration and switches solenoid valves L27a and R27b to achieve more appropriate pump operation.

[0094] According to the second embodiment, since the coil springs 14 of each connecting shaft 11a, 11b are mounted in an off-center position, a structure can be made that is less likely to interfere with the piping of the pump's suction port 16 and discharge port 17. This makes it possible to miniaturize the entire pump and improve the flexibility of the piping.

[0095] As shown in Figure 6, when solenoid valves L27a and R27b are ON, air is introduced into the working chambers 6a and 6b, the suction valves 18a and 18b are closed, and the discharge valves 19a and 19b are open, and during the overlapping period when the transferred fluid is discharged from both pump chambers 5a and 5b, the coil spring 14 contracts as described above. Consequently, the tip of the detection plate 23b on the shaft section L12 side reaches the displacement sensor 23a on the shaft section R13 side, and the contraction of the coil spring 14 is detected.

[0096] [Third Embodiment] Figure 7 is an explanatory diagram showing a partial configuration of a twin reciprocating pump according to the third embodiment of the present invention. Figure 7(a) shows the state of the coil spring 14 before contraction, and Figure 7(b) shows the state of the coil spring 14 when contracted.

[0097] As shown in Figure 7(a), in the third embodiment, the shaft portion L12 of the connecting shaft 11a is formed in a hollow shape so as to have an internal space 12a. A rod-shaped detection body 23c, which is a detection part that can move back and forth within the internal space 12a of the shaft portion R13, is fixed to the tip of the shaft portion R13. A displacement sensor 23a is mounted at a predetermined position on the shaft portion L12 so as to face the internal space 12a.

[0098] As shown in Figure 7(b), during the overlap period OP described above, the coil spring 14 contracts, so that the detection body 23c of the shaft R13 reaches the displacement sensor 23a in the internal space 12a of the shaft L12, and the contraction of the coil spring 14 is detected. In the structure of the third embodiment, there is no need to provide a detection plate 23b around the connecting shaft 11a, so the structure around the connecting shaft 11a can be simplified. A damper spring 14a is arranged inside the coil spring 14 of the connecting shaft 11a, for example, which exerts an effect of strengthening the contraction force during the contraction of the coil spring 14.

[0099] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0100] For example, in the above embodiment, a coil spring 14 is provided as an expandable member on the connecting shafts 11a and 11b, but the expandable member may be made of another elastic body. Alternatively, a damper may be provided along with the coil spring 14 or other elastic body as an expandable member. The damper reduces the biasing force when the coil spring 14 extends from its contracted state, so it is expected to prevent the generation of excessive suction pressure on the suction side due to the release of energy stored in the coil spring 14 and suppress the amplification of pulsation. Furthermore, in the above embodiment, a double reciprocating pump using a pair of deformable bellows 3a and 3b as movable partition members was exemplified, but the present invention can also be applied to a double reciprocating pump using a pair of movable pistons as movable partition members.

[0101] Furthermore, in the above embodiment, it was explained that the controller 25 drives a pair of bellows L3a and bellows R3b based on judgment information indicating whether or not the displacement sensor 23a and proximity switches L21a and R21b are detected, the order, and the time difference, so that, for example, this judgment information indicates that the detection of the displacement sensor 23a and proximity switches L21a and R21b is simultaneous. However, it is not limited to this. That is, since the judgment information indicates whether or not the detection is performed, the order, and the time difference, it is also possible, for example, to insert an on-delay timer into the digital detection signal (detection output) of either the displacement sensor 23a or the proximity switches L21a and R21b to create a time difference in the timing at which the digital detection signal is input to the controller 25. In this case, the detection by the displacement sensor 23a and the proximity switches L21a and R21b will not occur simultaneously. However, the controller 25 should drive the bellows L3a and R3b in the same way as when the detections were substantially simultaneous, taking into account the time difference set by the on-delay timer. Alternatively, for example, by changing the detection position of the displacement sensor 23a without using the on-delay timer, a time difference can be created in the timing at which the digital detection signal is input to the controller 25. In this case as well, the bellows L3a and R3b should be driven in the same way as when the detections were substantially simultaneous, taking the time difference into account. [Explanation of symbols]

[0102] 1 Pump head 2a,2b 10 3a Bellows L 3b Bellows R 4a, 4b Shaft fixing plate 5a, 5b Pump Room 6a,6b Working chamber 7a, 7b shafts 9a,9b connection plate 11a, 11b Connecting shaft 12 Shaft section L 13 Shaft section R 14. Coil spring 16 Inlet 17 Outlet 21a Proximity Switch (SW) L 21b Proximity switch (SW) R 23a Displacement sensor (photomicro sensor) 23b Detection plate 23c Detector 25 Controllers 26a Regulator L 26b Regulator R 27a Solenoid valve L 27b Solenoid valve R 100 Double reciprocating bellows pump

Claims

1. A case member that forms a pair of spaces along the axial direction inside, A pair of movable partition members are arranged within the pair of spaces so as to be deformable or movable in the axial direction, and each of the pair of spaces is divided in the axial direction into a pump room and an operating room, A connecting shaft that connects the pair of movable partition members so as to be extendable and retractable in the axial direction via an expandable member, A suction valve is provided on the suction side of the pump chamber to guide the fluid to be transferred into the pump chamber, A discharge valve is provided on the discharge side of the pump chamber to discharge the transfer fluid from the pump chamber, A valve mechanism for introducing working fluid into the working chamber and discharging the working fluid from the working chamber, A displacement sensor that detects when the extension member of the connecting shaft has contracted, A proximity sensor detects when the pair of movable partition members have reached the end of their movement stroke, A controller that drives the pair of movable partition members by switching the valve mechanism based on the outputs of the displacement sensor and the proximity sensor, Equipped with, The aforementioned controller, Based on the output, judgment information indicating the presence or absence, order, and time difference of detections by the displacement sensor and the proximity sensor is used to determine the overlap period during which the compression processes of one pump chamber and the other pump chamber partially overlap, and the pair of movable partition members are driven so that the judgment information changes according to the judgment result. A double-acting reciprocating pump.

2. The aforementioned controller, The overlapping period is determined based on the judgment information for each stroke of deformation or movement of the pair of movable partition members. The determination information drives the pair of movable partition members to indicate that the displacement sensor and the proximity sensor are detecting something simultaneously. A double reciprocating pump according to claim 1.

3. The aforementioned controller, If the judgment information indicates that the proximity sensor detects a displacement sensor before the displacement sensor detects a displacement sensor, or that the proximity sensor detects a displacement sensor but the displacement sensor does not, then it is determined that the start of the overlapping period is delayed, and the pair of movable partition members are driven so that the time difference in the start timing of deformation or movement of the pair of movable partition members decreases by a certain amount of time for each stroke until the proximity sensor and the displacement sensor detect a displacement sensor simultaneously. The twin reciprocating pump according to claim 2.

4. The aforementioned controller, If the judgment information indicates that the displacement sensor detects the displacement before the proximity sensor, or that the displacement sensor detects the displacement but the proximity sensor does not, then it is determined that the overlap period started earlier, and the pair of movable partition members are driven so that the time difference in the start timing of deformation or movement of the pair of movable partition members increases by a certain amount of time with each stroke until the detection of the displacement sensor and the proximity sensor occurs simultaneously. The twin reciprocating pump according to claim 2.

5. The displacement sensor is positioned on one shaft portion of the connecting shaft via the telescopic member and detects the contraction of the telescopic member by detecting a detected portion positioned on the other shaft portion via the telescopic member. A double reciprocating pump according to any one of claims 1 to 4.

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