JP2007291857A - Metering pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metering pump device highly accurately performing metering discharge, even when pressure difference is generated between both sides of an outflow-side valve. <P>SOLUTION: In the metering pump device 1, two reciprocating pump devices 10A, 10B are used for superimposing commencement and termination of a discharge period of one reciprocating pump on commencement and termination of a discharge period of the other reciprocating pump device. After suction motion and before the discharge period, an inflow-side valves 11Ai, 11Bi and the outflow-side valves 11Ao, 11Bo are closed to expand or contract the volume of a pump chamber, to perform correction operation to eliminate the pressure difference. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metering pump device including a plurality of reciprocating pump devices.

Some metering pump devices use a reciprocating pump device. However, in such a reciprocating pump, there is a point where the discharge amount is always 0 at the top dead center or the bottom dead center. There is a problem. Therefore, two reciprocating pump devices are connected in parallel, and when one reciprocating pump device finishes discharging, the other reciprocating pump devices start discharging so that the overall discharge flow rate is always constant. What was comprised is proposed (refer patent document 1).
JP 2001-207951 A

  However, even when two reciprocating pump devices are phased like the reciprocating pump device disclosed in Patent Document 1, if there is a pressure difference between the pump chamber and the common discharge port side, the outflow side valve is opened. Immediately after switching to the above, there is a problem that fluid flows out from the pump chamber to the common discharge port side or fluid flows from the common discharge port side into the pump chamber, and the discharge amount fluctuates. In the metering pump device disclosed in Patent Document 1, after the fluid is sucked into the pump chamber, the inflow side valve is opened to contract the pump chamber in order to release bubbles from the pump chamber. In such an operation, it is impossible to prevent variation in the discharge amount per unit time when there is a pressure difference between the pump chamber and the common discharge port side.

  In view of the above problems, an object of the present invention is to provide a metering pump device capable of performing metered discharge with high accuracy even when a pressure difference is generated on both sides of an outflow side valve.

  In order to solve the above-described problems, the present invention includes a plurality of reciprocating pump devices each having an inflow side valve and an outflow side valve connected to the inflow side and the outflow side, respectively, and the outflow to the plurality of reciprocating pump devices. In a metering pump device having a common discharge port connected via a side valve, the metering pump device has a control unit that controls the inflow side valve, the outflow side valve, and the reciprocating pump device, and the control unit includes the plurality of reciprocating pumps. The discharge period and the standby period are set by shifting the timing for each pump device, and the end and the start of the discharge period of the other reciprocating pump device are superimposed on the start and the end of the discharge period. After performing the suction operation into the pump chamber, before the discharge period, both the inflow side valve and the outflow side valve are closed and the pump chamber is closed. Characterized in that to perform the correction operation for eliminating the pressure difference between the pressure in the pump chamber is expanded or contracted volume as common discharge port side.

  In the present invention, a plurality of reciprocating pump devices are used, and the top dead center or bottom dead center in the reciprocating pump device is used to superimpose the end and start of the discharge period of another reciprocating pump device on the start and end of the discharge period. Even when there is a point where the discharge amount becomes 0, the discharge flow rate as a whole is always constant. In addition, after the suction operation, before the discharge period, both the inflow side valve and the outflow side valve are closed to expand or contract the volume in the pump chamber to perform a correction operation to eliminate the pressure difference. Even when there is a pressure difference between the two sides of the sheet, the quantitative discharge can be performed with high accuracy.

  In the present invention, each of the plurality of reciprocating pump devices may be configured to be connected to a separate suction port via a separate inflow side valve. You may employ | adopt the structure provided with the common inlet port connected via a valve | bulb.

  In the present invention, it is preferable that the reciprocating pump device has a drive source that is a stepping motor or an AC synchronous motor. In such a motor, even when energization is stopped, the position of the rotor can be held by the holding force. Therefore, even when the position of the valve body is held, unlike the solenoid or the like, it is not necessary to energize constantly, so that power consumption can be reduced. When the drive source of the reciprocating pump device is a stepping motor, the amount of change in the internal volume of the pump chamber corresponding to one step of the stepping motor is 1/100 or less with respect to the internal volume of the entire pump chamber. It is preferable. With this configuration, a metering pump device with high resolution can be realized.

  In the present invention, a monitoring device that directly or indirectly monitors the pressure difference between the pressure in the pump chamber of the reciprocating pump device and the common discharge port side is provided, and the control unit is a monitoring result of the monitoring device. Based on the above, it is possible to adopt a configuration in which the correction operation is performed when there is a pressure difference between the pressure in the pump chamber and the common discharge port side.

  In the present invention, the monitoring device includes a plurality of first pressure sensors that monitor pressures in the pump chambers of the plurality of reciprocating pump devices, and a second pressure sensor that monitors the pressure on the common discharge port side. It is possible to employ a configuration in which the pressure difference is monitored by comparing the detection results of the first pressure sensor and the second pressure sensor.

  In the present invention, the monitoring device includes a plurality of pressure sensors that monitor pressures in the pump chambers of the plurality of reciprocating pump devices, and the reciprocating pump device that has performed the suction operation among the plurality of reciprocating pump devices. The detection result of the pressure sensor arranged in the pump chamber is compared with the detection result of the pressure sensor arranged in the pump chamber of the reciprocating pump device in which the output side valve is open, and the pressure difference is calculated. A monitoring configuration can be employed.

  The metering pump device capable of realizing such control includes a plurality of reciprocating pump devices each having an inflow side valve and an outflow side valve connected to the inflow side and the outflow side, respectively, and the outflow side with respect to the plurality of reciprocating pump devices. A common discharge port connected via a valve is provided, and a pressure sensor for monitoring the pressure in each pump chamber of the plurality of reciprocating pump devices is further provided.

  In the present invention, when the number of the reciprocating pump devices is two, the control device may set the expansion rate of the pump chamber when performing the suction operation to be higher than the contraction rate of the pump chamber during the discharge period. Good.

  In the metering pump device according to the present invention, a plurality of reciprocating pump devices are used, and the end and start of the discharge period of another reciprocating pump device are superimposed on the start and end of the discharge period. Even when there is a point where the discharge amount becomes zero at the point or the bottom dead center, the discharge flow rate as a whole is always constant. In addition, after the suction operation, before the discharge period, both the inflow side valve and the outflow side valve are closed to perform a correction operation for expanding or contracting the volume in the pump chamber to eliminate the pressure difference. When there is a pressure difference between the inflow side and the discharge side of the discharge side valve, as a result, even when there is a pressure difference between both sides sandwiching the outflow side valve, the quantitative discharge can be performed with high accuracy.

  Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
(Device configuration)
FIG. 1 is a conceptual diagram showing a basic configuration of a metering pump device to which the present invention is applied. FIG. 2 is a perspective view showing a configuration example of a metering pump device to which the present invention is applied. FIG. 3 is a longitudinal sectional view of a main body portion of the metering pump device shown in FIG.

  As shown in FIG. 1, a metering pump device 1 according to the present embodiment is a pump device that performs a liquid or gas metering discharge, and includes inflow valves 12Ai, 11Bi and an outflow side in inflow channels 12Ai, 12Bi and outflow channels 12Ao, 12Bo. Two reciprocating pump devices 10A and 10B to which valves 11Ao and 11Bo are respectively connected are provided. For the two reciprocating pump devices 10A and 10B, a common outlet 13o is configured in a common outlet passage 12o connected via the outlet valves 11Ao and 11Bo. Further, in the metering pump device 1 of the present embodiment, the common suction port 13i is configured in the common inflow path 12i connected to the two reciprocating pump devices 10A and 10B via the inflow side valves 11Ai and 11Bi. Here, the reciprocating pump devices 10A and 10B have the same configuration, and the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo all have the same configuration. The inflow channels 12Ai and 12Bi have the same configuration, and the outflow channels 12Ao and 12Bo have the same configuration.

  For example, as shown in FIG. 2, the metering pump device 1 according to this embodiment includes a rectangular parallelepiped main body portion 2 in which a plurality of plates are stacked, and a control connected to the main body portion 2 via a connector or a cable. The apparatus 3 (control part) is provided. The main body portion 2 includes a bottom plate 75, a base plate 76, a flow path component plate 77, and an upper plate 78 that covers the upper surface of the flow channel component plate 77 to close the upper surface of the flow path. The pipe 781 constituting the common discharge port 13o and the pipe 782 constituting the common suction port 13i are connected.

  As will be described in detail later, as shown in FIG. 3, each of the reciprocating pump devices 10A and 10B is driven by a valve body composed of a diaphragm valve 170 disposed in the pump chamber 20 and the pump chamber 20 by driving the valve body. And a driving device 105 having a stepping motor (drive source) that contracts and expands the internal volume, and when the stepping motor rotates in one direction, the diaphragm valve 170 is arranged in a direction in which the internal volume of the pump chamber 20 increases. The diaphragm valve 170 is driven in such a direction that the internal volume of the pump chamber 20 contracts when the stepping motor rotates in the other direction. Here, the amount of change in the internal volume of the pump chamber 20 corresponding to one step of the stepping motor is 1/100 or less with respect to the internal volume of the entire pump chamber 20.

  Further, the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo are active valves each including a valve body (diaphragm valve 260) and a linear actuator 201, and each perform an open / close operation independently.

(Operation)
FIG. 4 is a timing chart showing the operation of the metering pump device of this embodiment, and such control is performed by the control device 3 shown in FIG.

  FIG. 4A shows a state in which the valve element is driven by the stepping motor in the first reciprocating pump device 10A out of the two reciprocating pump devices 10A and 10B. The chamber 20 contracts and fluid is discharged, and the pump chamber 20 expands and the liquid is sucked during the period in which the waveform is downward. FIGS. 4B and 4C show how the inflow side valve 11Ai and the outflow side valve 11Ao are driven with respect to the first reciprocating pump device 10A. When a signal having an upward waveform is input, Thereafter, the valve is opened until a signal having a downward waveform is input, and when a signal having a downward waveform is input, the valve is thereafter closed until a signal having an upward waveform is input. FIG. 4D shows a state in which the valve element is driven by the stepping motor in the second reciprocating pump device 10B. During a period in which the waveform is upward, the pump chamber 20 is contracted and liquid is discharged. In the downward period, the pump chamber 20 expands and the liquid is sucked. 4 (e) and 4 (f) show how the inflow side valve 11Bi and the outflow side valve 11Bo are driven with respect to the second reciprocating pump device 10B. When a signal having an upward waveform is input, Thereafter, the valve is opened until a signal having a downward waveform is input, and when a signal having a downward waveform is input, the valve is thereafter closed until a signal having an upward waveform is input. FIG. 4G shows the result of combining the discharge amounts of liquid discharged from the first reciprocating pump device 10A and the second reciprocating pump device 10B (discharge amounts from the common discharge port 13o). (H) shows the result of combining the suction amounts of liquid sucked into the first reciprocating pump device 10A and the second reciprocating pump device 10B (suction amount from the common suction port 13i).

  In this embodiment, the operation for each time will be described later. First, as shown in the upper part of FIG. 4, the control device 3 shifts the timing for each of the two reciprocating pump devices 10A, 10B at the discharge period T1A, T1B and standby periods T2A and T2B are set, and the other reciprocating pump with respect to the start and end of the discharge period (for example, discharge period T1A) of one reciprocating pump apparatus (for example, first reciprocating pump apparatus 10A) The end and start of the discharge period (for example, discharge period T1B) of the apparatus (for example, the second reciprocating pump device 10B) are overlapped.

  In addition, the control device 3 performs the suction operation into the pump chamber 20 during the standby periods T2A and T2B, and then before the discharge periods T1A and T1B, both the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo. Is closed, the volume in the pump chamber 20 is contracted, and a correction operation for eliminating the pressure difference is performed.

  In FIG. 4, first, until the time t0, the reciprocating pump devices 10A and 10B are in a stopped state, and the pump chambers 20 are in a state where the liquid (fluid) has been sucked. All the valves are closed. In this state, as shown in FIGS. 4A, 4B, and 4C, at time t0, after the outflow side valve 11Ao for the first reciprocating pump device 10A is opened at time t0, at time t1. As a result of the valve body being driven in the direction in which the first reciprocating pump device 10A contracts the pump chamber 20, liquid discharge is started. Such discharge is continued in the discharge period T1A up to time t8, during which the first reciprocating pump device 10A discharges the liquid in a fixed amount.

  Then, at time t8, after the outflow side valve 11Ao for the first reciprocating pump device 10A is closed and the discharge of the liquid is stopped, the stop is continued in the waiting period T2A until time t13. In the waiting period T2A, after the inflow side valve 11Ai for the first reciprocating pump device 10A is opened at time t9, the valve body in the first reciprocating pump device 10A passes through the pump chamber 20 from time t10 to t11. The liquid is sucked by being driven in the expanding direction.

  Next, at time t13, after the outflow side valve 11Ao for the first reciprocating pump device 10A is opened again, at time t14, the valve body again enters the pump chamber 20 in the first reciprocating pump device 10A. Driven in the contracting direction, the discharge of the liquid is started. Such discharge is continued in the discharge period T1A up to time t22, during which the first reciprocating pump device 10A discharges the liquid in a fixed amount.

  Then, at time t22, after the outflow side valve 11Ao for the first reciprocating pump device 10A is closed and the discharge of the liquid is stopped, the stop is continued in the waiting period T2A until time t27. In the waiting period T2A, after the inflow side valve 11Ai for the first reciprocating pump device 10A is opened at time t23, the valve body moves through the pump chamber 20 in the first reciprocating pump device 10A from time t24 to t25. The liquid is sucked by being driven in the expanding direction. Such a series of operations is then repeated.

  On the other hand, as shown in FIGS. 4D, 4E, and 4F, the same operation is performed in the second reciprocating pump device 10B, but the timing is shifted. Accordingly, after the outflow side valve 11Bo for the second reciprocating pump device 10B is opened at time t6, the valve body is driven in the direction in which the valve body contracts the pump chamber 20 at the second reciprocating pump device 10B at time t7. Then, the discharge of the liquid is started. Such discharge is continued in the discharge period T1B up to time t15, during which the second reciprocating pump device 10B discharges the liquid in a constant amount. Next, at time t15, the outflow side valve 11Bo for the second reciprocating pump device 10B is closed and the discharge of the liquid is stopped, and this stop is continued in the waiting period T2B until time t20. In the waiting period T2B, after the inflow side valve 11Bi with respect to the second reciprocating pump device 10B is opened at time t16, the valve body moves through the pump chamber 20 in the second reciprocating pump device 10B from time t17 to t18. The liquid is sucked by being driven in the expanding direction. Such a series of operations is then repeated.

  Here, as at times t7 to t8 and times t21 to t22, the end of the discharge period T1A of the first reciprocating pump device 10A and the start of the discharge period T1B of the second reciprocating pump device 10B overlap each other, and the time As from t14 to t15, the end of the discharge period T1B of the second reciprocating pump device 10B overlaps the start of the discharge period T1A of the first reciprocating pump device 10A. For this reason, as shown in FIG. 4 (h), the suction of the liquid is intermittently performed, but as shown in FIG. 4 (g), the first reciprocating pump device 10A and the second reciprocating pump device 10B The discharge speed (discharge amount per unit time) obtained by combining the discharge amount of liquid to be discharged (discharge amount from the common discharge port) is always constant.

(Correction action for pressure difference)
In the metering pump device 1 of this embodiment, if there is a pressure difference between the inside of the pump chamber 20 and the common discharge port 13o, the common discharge port from the pump chamber 20 immediately after the outflow valves 11Ao and 11Bo are switched to the open state. The liquid flows out to the 13o side, or the liquid flows into the pump chamber 20 from the common discharge port 13o side, and the discharge amount varies.

  Therefore, in this embodiment, the control device 3 is set on the condition that the pressure on the common discharge port 13o side is higher than the pressure in the pump chamber 20 based on the usage state of the metering pump device 1. That is, the control device 3 performs the suction operation into the pump chamber 20 in the standby periods T2A and T2B according to preset conditions, and then before the discharge periods T1A and T1B, the periods t5 to t6 and t12 to At t13 and t19 to t20, both the inflow side valve 11Ai and the outflow side valve 11Ao (or both the inflow side valve 11Bi and the outflow side valve 11Bo) are closed and the first reciprocating pump device 10A (or the second reciprocating pump). The correction operation for driving the valve body in the direction of contracting the volume in the pump chamber 20 of the apparatus 10B) is performed. For example, in the standby period T2A, after performing the suction operation into the pump chamber 20, before the discharge period T1A, in the periods t5 to t6 and t19 to t20, the inflow side valve 11Ai for the first reciprocating pump device 10A and Both the outflow side valves 11Ao are closed, the valve body is driven in a direction to contract the volume in the pump chamber 20 of the first reciprocating pump device 10A, the pressure in the pump chamber 20 is increased, and the common discharge port 13o side is connected. To eliminate the pressure difference. In addition, after the suction operation into the pump chamber 20 is performed in the standby period T2B and before the discharge period T1B, in the period t12 to t13, the inflow side valve 11Bi and the outflow side valve 11Bo for the second reciprocating pump device 10B. Are closed, the valve body is driven in a direction to shrink the volume in the pump chamber 20 of the second reciprocating pump device 10B, the pressure in the pump chamber 20 is increased, and the pressure difference from the common discharge port 13o side is increased. Eliminate.

  In this embodiment, the pressure in the pump chamber 20 before discharge is increased on the assumption that the pressure on the common discharge port 13o side is higher than the pressure in the pump chamber 20, but the common discharge port is higher than the pressure in the pump chamber 20. When the pressure on the 13o side is low, as shown in FIG. 5, after performing the suction operation into the pump chamber 20 in the standby periods T2A and T2B, before the discharge periods T1A and T1B, the periods t5 to t6 In t12 to t13 and t19 to t20, the correction operation for driving the valve body in the direction of expanding the volume in the pump chamber 20 by closing both the inflow side valve and the outflow side valve may be performed.

(Main effects of this form)
As described above, in the metering pump device 1 of the present embodiment, the two reciprocating pump devices 10A and 10B are used, and the discharge period of the other reciprocating pump device with respect to the start and end of the discharge period of one reciprocating pump device. Therefore, even when there is a point where the discharge amount becomes 0 at the top dead center or the bottom dead center in the reciprocating pump devices 10A and 10B, the discharge flow rate as a whole is always constant.

  In addition, after the suction operation, before the discharge periods T1A and T1B, the correction operation T3A that closes both the inflow side valve and the outflow side valve to expand or contract the volume in the pump chamber 20 to eliminate the pressure difference. Since T3B is performed, even when there is a pressure difference between both sides sandwiching the outflow side valves 11Ao and 11Bo, the quantitative discharge can be performed with high accuracy. Therefore, when a diaphragm valve is used as the valve body, unnecessary deformation may occur in the diaphragm valve due to the pressure difference between the internal pressure of the pump chamber 20 and the atmospheric pressure. In this embodiment, such deformation is corrected. Thus, suction and discharge can be performed, and the accuracy of the suction amount and the discharge amount is high.

  Further, in the reciprocating pump devices 10A and 10B, the operation is controlled by a signal pattern supplied to the stepping motor used in the driving device 105. Therefore, unlike the configuration in which the operation of the reciprocating pump device is controlled by a cam mechanism, the reciprocating pump devices 10A and 10B Since the moving speed of the valve element (diaphragm valve 170) can be easily changed simply by changing the signal pattern to be performed, it is possible to stably cope with conditions from a small discharge amount per unit time to a large condition. Even under the condition where the discharge amount per unit time is large, the number of reciprocations of the diaphragm valve 170 can be reduced, so that the life of the metering pump device 1 is long.

  In addition, since the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo are active valves that open and close independently, it is possible to prevent both the inflow side and the outflow side from being opened. Therefore, even if the valve suction port 13i side is higher in pressure than the discharge port 13o side, forward flow does not occur, and the metering pump device 1 can always perform metered discharge. Further, when the reciprocating pump devices 10A and 10B are operated with all of the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo opened, the liquid can be extracted from the reciprocating pump devices 10A and 10B. Therefore, it is possible to easily prevent freezing.

  Further, in the metering pump device 1 of the present embodiment, since the suction side and the discharge side have the same configuration, the suction side and the discharge side can be switched to operate. Therefore, it is possible to recover the liquid from the discharge side to the suction side.

  Furthermore, a stepping motor is used as a driving source for the driving device 105 of the reciprocating pump devices 10A and 10B, and the amount of change in the internal volume of the pump chamber 20 corresponding to one step of the stepping motor is It is 1/100 or less with respect to the internal volume. For this reason, the metering pump device 1 of this embodiment has high resolution. Further, the stepping motor can hold the position of the rotor by the holding force even when energization is stopped. Therefore, even when the position of the diaphragm valve 170 is held, unlike the solenoid or the like, it is not always necessary to energize, so that power consumption can be reduced. From this point of view, an AC synchronous motor may be used instead of the stepping motor.

[Embodiment 2]
In the first embodiment, the correction operation shown in FIG. 4 or 5 is set in advance, but in this embodiment, the pressure in the pump chamber 20 of the reciprocating pump devices 10A and 10B and the common discharge port 13o side are set. A monitoring device that directly or indirectly monitors the pressure difference between them is provided, and the control device 3 has a pressure difference between the pressure in the pump chamber 20 and the common discharge port side based on the monitoring result of the monitoring device. At some point, the correction operation described with reference to FIG. 4 or 5 is performed.

  As such a monitoring device, in this embodiment, as shown in FIG. 6, the first pressure sensors 14A and 14B for monitoring the pressure in each pump chamber 20 of the reciprocating pump devices 10A and 10B, and the common discharge port 13o side And a second pressure sensor 14o for monitoring the pressure of the first pressure sensor. In the monitoring device configured as described above, for example, after the suction operation into the pump chamber 20 is finished, the detection results of the first pressure sensors 14A and 14B and the second pressure sensor 14o are compared with each other to detect the pressure difference. To monitor. Then, based on the monitoring result, the control device 3 determines which of the conditions shown in FIG. 4 and the conditions shown in FIG. Further, when there is no pressure difference between the inside of the pump chamber 20 and the common discharge port side, the correction operation is not performed.

[Embodiment 3]
In the first embodiment, the correction operation shown in FIG. 4 or FIG. 5 is set in advance. In this embodiment, as in the second embodiment, the pressure in the pump chamber 20 of the reciprocating pump devices 10A and 10B A monitoring device that directly or indirectly monitors the pressure difference from the common discharge port 13o side is provided, and the control device 3 determines the pressure in the pump chamber 20 and the common discharge port side based on the monitoring result of the monitoring device. When there is a pressure difference between them, the correction operation described with reference to FIG. 4 or 5 is performed.

  As such a monitoring device, in this embodiment, as shown in FIG. 7, pressure sensors 14A and 14B for monitoring the pressure in each pump chamber 20 of the reciprocating pump devices 10A and 10B are used. In the monitoring device configured as described above, for example, at time t19, the detection result of the pressure sensor 14B disposed in the pump chamber 20 of the reciprocating pump device 10B that has finished the suction operation into the pump chamber 20, and the reciprocating pump device. The pressure difference between the pressure inside the pump chamber 20 and the common discharge port side is monitored by comparing the detection result with the pressure sensor 14A arranged in the pump chamber 20 of 10A. This is because the detection result of the pressure sensor 14A of the reciprocating pump device 10A at time t14 is equal to the pressure on the common discharge port side. Then, based on the monitoring result, the control device 3 determines whether the correction operation performed at time t19 to t20 is performed under the condition shown in FIG. 4 or the condition shown in FIG. Further, when there is no pressure difference between the inside of the pump chamber 20 and the common discharge port side, the correction operation is not performed.

(Specific configuration example of reciprocating pump device)
With reference to FIG. 3 and FIG. 8, the specific structural example of reciprocating pump apparatus 10A, 10B used for the metering pump apparatus of this form is demonstrated.

  FIG. 8 is an exploded perspective view of a state in which the reciprocating pump device used in the metering pump device to which the present invention is applied is vertically divided. As shown in FIGS. 3 and 8, the main body portion 2 of the metering pump device 1 of the present embodiment has a structure in which a bottom plate 75, a base plate 76, a flow path constituting plate 77, and an upper plate 78 are laminated in this order. The reciprocating pump devices 10 </ b> A and 10 </ b> B are configured in holes formed in the base plate 76. In this embodiment, the reciprocating pump devices 10 </ b> A and 10 </ b> B drive the pump chamber 20, a diaphragm valve 170 (valve element) that expands and contracts the internal volume of the pump chamber 20 to suck and discharge liquid, and the diaphragm valve 170. And a driving device 105.

  The driving device 105 includes an annular stator 120, a rotating body 103 disposed coaxially inside the stator 120, a moving body 160 disposed coaxially inside the rotating body 103, and the rotating body 103. A conversion mechanism 140 that converts the rotation into a force that moves the moving body 160 in the axial direction and transmits the rotation to the moving body 160 is provided. Here, the driving device 105 is mounted between the base plate 79 and the base plate 76 in the space formed in the base plate 76.

  In the driving device 105, the stator 120 has a structure in which a unit including a coil 121 wound around a bobbin 123 and two yokes 125 arranged so as to cover the coil 121 is stacked in two stages in the axial direction. ing. In this state, in any of the two upper and lower units, the pole teeth protruding in the axial direction from the inner peripheral edges of the two yokes 125 are alternately arranged in the circumferential direction, and function as a stator of the stepping motor.

  The rotating body 103 includes a cup-shaped member 130 that opens upward, and an annular rotor magnet 150 that is fixed to the outer peripheral surface of the cylindrical body 131 of the cup-shaped member 130. A concave portion 135 is formed in the center of the bottom wall 133 of the cup-shaped member 130 and is recessed upward in the axial direction. A bearing portion 751 for receiving the ball 118 disposed in the concave portion 135 is formed on the base plate 79. An annular step 766 is formed on the inner surface on the upper end side of the base plate 76, while the upper end portion of the cup-shaped member 130 is formed by the upper end portion of the body 131 and the annular flange portion 134. An annular stepped portion facing the annular stepped portion 766 on the 76 side is formed, and in the annular space defined by these annular stepped portions, an annular retainer 181 and a position spaced apart in the circumferential direction by the retainer 181 A bearing 180 composed of a bearing ball 182 held on the surface is disposed. Thus, the rotating body 103 is in a state of being supported by the main body portion 2 so as to be rotatable around the axis.

  In the rotating body 103, the outer peripheral surface of the rotor magnet 150 faces the pole teeth arranged in the circumferential direction along the inner peripheral surface of the stator 120. Here, on the outer peripheral surface of the rotor magnet 150, the S pole and the N pole are alternately arranged in the circumferential direction, and the stator 120 and the cup-shaped member 130 constitute a stepping motor.

  The moving body 160 includes a bottom wall 161, a cylindrical portion 163 protruding in the axial direction from the center of the bottom wall 161, and a body portion 165 formed in a cylindrical shape so as to surround the cylindrical portion 163. A male screw 167 is formed on the outer periphery of the body portion 165.

  In this embodiment, when configuring the conversion mechanism 140 for reciprocating the moving body 160 in the axial direction by the rotation of the rotating body 103, the inner peripheral surface of the body 131 of the cup-shaped member 130 is spaced apart in the circumferential direction. While the female screw 137 is formed at four locations, the male screw 167 that forms the power transmission mechanism 141 by engaging with the female screw 137 of the cup-shaped member 130 is formed on the outer peripheral surface of the body 165 of the moving body 160. ing. Therefore, if the moving body 160 is arranged inside the cup-shaped member 130 so that the male screw 167 and the female screw 137 mesh with each other, the moving body 160 is supported on the inside of the cup-shaped member 130. In addition, six long holes 169 are formed as through holes in the bottom wall 161 of the moving body 160 in the circumferential direction, while six protrusions 769 extend from the base plate 76, and a lower end portion of the protrusion 769. Is fitted in the long hole 169, and the rotation prevention mechanism 149 is configured. That is, when the cup-shaped member 130 is rotated, the moving body 160 is prevented from rotating by the rotation prevention mechanism 149 including the protrusion 769 and the elongated hole 169, and therefore the rotation of the cup-shaped member 130 is caused by the female screw 137. As a result of being transmitted to the moving body 160 via the power transmission mechanism 141 including the male screw 167 of the moving body 160, the moving body 160 is linearly formed on one side and the other side in the axial direction according to the rotation direction of the rotating body 103. Will move.

  A diaphragm valve 170 is directly connected to the moving body 160. The diaphragm valve 170 has a cup shape including a bottom wall 171, a cylindrical body portion 173 that rises in the axial direction from the outer peripheral edge of the bottom wall 171, and a flange portion 175 that extends from the upper end of the body portion 173 to the outer peripheral side. The center portion of the bottom wall 171 is fixed to the set screw 178 and the cap 179 from above and below in a state where the center portion of the bottom wall 171 covers the cylindrical portion 163 of the moving body 160. Further, the outer peripheral edge of the flange portion 175 of the diaphragm valve 170 is a thick portion that functions as liquid tightness and positioning, and this thick portion is the base around the through hole 21 of the flow path component plate 77. It is fixed between the plate 76 and the flow path constituting plate 77. In this manner, the diaphragm 170 defines the lower surface of the pump chamber 20 and ensures liquid tightness between the base plate 76 and the flow path component plate 77 around the pump chamber 20.

  In this state, the body portion 173 of the diaphragm valve 170 is folded back in a U-shaped cross section, and the shape of the folded portion 172 changes depending on the position of the moving body 160. However, in this embodiment, the movable body 160 is configured between the first wall surface 168 formed of the outer peripheral surface of the cylindrical portion 163 and the second wall surface 768 formed of the inner peripheral surface of the protrusion 769 extending from the base plate 76. A folded portion 172 having a U-shaped cross section of the diaphragm valve 170 is disposed in the annular space. Accordingly, regardless of the state of the diaphragm valve 170, the folded portion 172 is deformed so as to expand or roll up along the first wall surface 168 and the second wall surface 768 while being held in the annular space. To do.

  In addition, a single groove 136 is formed on the bottom wall 133 of the cup-shaped member 130 over an angular range of 270 ° in the circumferential direction, while a protrusion (not shown) extends downward from the bottom surface of the moving body 160. ) Is formed. Here, the moving body 160 does not rotate around the axis but moves in the axial direction, whereas the rotating body 103 rotates around the axis but does not move in the axial direction. Therefore, the protrusion and the groove 136 function as a stopper that defines the stop positions of the rotating body 103 and the moving body 160. That is, the depth of the groove 136 is changed in the circumferential direction, and when the moving body 160 moves downward in the axial direction, the protrusion fits in the groove 136 and the end of the groove 136 is rotated by the rotation of the rotating body 103. Abuts against the protrusion. As a result, the rotation of the rotating body 103 is blocked, and the stop position of the rotating body 103 and the moving body 160, that is, the maximum expansion position of the inner volume of the diaphragm valve 170 is defined.

  In the reciprocating pump devices 10A and 10B configured as described above, the driving device 105 drives the diaphragm valve 170 in a direction in which the internal volume of the pump chamber 20 increases when the stepping motor rotates in one direction, and the stepping motor The diaphragm valve 170 is driven in such a direction that the internal volume of the pump chamber 20 is reduced when it rotates in the direction. That is, when power is supplied to the coil 121 of the stator 120, the cup-shaped member 130 rotates, and the rotation is transmitted to the moving body 160 via the conversion mechanism 140. Therefore, the moving body 160 performs a reciprocating linear motion in the axial direction. As a result, the diaphragm valve 170 is deformed in accordance with the movement of the moving body 160 and expands and contracts the internal volume of the pump chamber 20, so that in the pump chamber 20, the inflow of liquid from the inflow paths 12Ai and 12Bi and the outflow path The liquid is discharged toward 12Ao and 12Bo.

  As described above, in the reciprocating pump devices 10A and 10B of this embodiment, the rotating body 103 is rotated by the stepping motor mechanism via the conversion mechanism 140 using the power transmission mechanism 141 including the male screw 167 and the female screw 137. And the movable body 160 to which the diaphragm valve 170 is fixed is reciprocated linearly. For this reason, since power is transmitted from the drive device 105 to the diaphragm valve 170 with the minimum necessary members, the reciprocating pump devices 10A and 10B can be reduced in size, thickness, and cost. Further, the moving body 160 can be finely fed by reducing the lead angle of the male screw 167 and the female screw 137 in the power transmission mechanism 141 or increasing the pole teeth of the driving side stator. Accordingly, since the volume of the pump chamber 20 can be strictly controlled, it is possible to perform a fixed amount discharge with high accuracy.

  Further, in this embodiment, the diaphragm valve 170 is used, but the folded portion 172 of the diaphragm valve 170 is developed along the first wall surface 168 and the second wall surface 768 while being held in the annular space. Or it deform | transforms so that it may wind up and an excessive sliding does not generate | occur | produce. Therefore, useless load does not occur and the life of the diaphragm valve 170 is long. Further, the diaphragm valve 170 does not deform even when it receives pressure from the liquid in the pump chamber 20. Therefore, according to the reciprocating pump devices 10A and 10B of the present embodiment, the quantitative discharge can be performed with high accuracy and the reliability is high.

  Furthermore, since the rotating body 103 is supported so as to be rotatable around the axis via the bearing ball 182 with respect to the main body portion 2, the sliding loss is small and the rotating body 103 is stably held in the axial direction. Therefore, the thrust in the axial direction is stable. Therefore, the drive device 105 can be reduced in size, improved in durability, and improved in discharge performance.

  In the above embodiment, a screw is used as the power transmission mechanism 141 of the conversion mechanism 140, but a cam groove may be used. Furthermore, in the above embodiment, a cup-shaped diaphragm valve is used as the valve body, but a diaphragm valve having another shape or a piston having an O-ring may be used.

[Specific configuration example of active valve]
With reference to FIG. 3 and FIG. 9, the specific structural example of the active valve used as inflow side valve | bulb 11Ai, 11Bi and outflow side valve | bulb 11Ao, 11Bo in the metering pump apparatus of this form is demonstrated. FIG. 9 is an explanatory view showing a longitudinal section of an active valve used as the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo in the metering pump device 1 to which the present invention is applied.

  3 and 9, the active valve includes a stepping motor 301 as a driving source, an inlet 308a and an outlet 308b. A lead screw 302 made of, for example, a right screw is press-fitted and fixed to the rotation shaft 301 a of the stepping motor 301, and the lead screw 302 rotates in the same direction as the rotation direction of the stepping motor 301. A female screw 303 a of the valve holding member 303 is screwed into the lead screw 302. Accordingly, when the stepping motor 301 rotates in the CCW direction (counterclockwise) as viewed from the lead screw 302 side, the valve holding member 303 approaches the stepping motor 301, while the stepping motor 301 is in the CW direction as viewed from the lead screw 302 side. When rotated clockwise, the valve holding member 303 moves away from the stepping motor 301. That is, the rotation of the lead screw 302 is converted into a linear motion because the lead screw 302 and the valve holding member 303 are engaged by screw connection and the valve holding member 303 is stopped.

  A spring receiving portion 303 b is provided concentrically on the outer peripheral side of the valve holding member 303, and the spring 304 is held by the spring receiving portion 303 b and the stepping motor 301. The spring 304 is formed of a compression coil spring and urges the valve holding member 303 in a direction away from the stepping motor 301. In the present embodiment, a compression coil spring is used. However, for example, a “tensile coil spring” may be used. In this case, the tension coil spring can be held on the surface opposite to the spring receiving portion 303b of the valve holding member 303.

  A convex diaphragm holding portion 303 c is provided at the central portion of the valve holding member 303, and this diaphragm holding portion 303 c is engaged with the undercut portion 260 a of the diaphragm valve 260. Here, the outer peripheral portion 260b of the diaphragm valve 260 is fixed by being sandwiched between the base plate 76 and the flow path constituting plate 77, and the outer peripheral bead 260e is also sandwiched and fixed. The bead 260e prevents fluid from leaking from the gap between the base plate 76 and the flow path component plate 77, and contributes to an improvement in sealing performance. Further, since the membrane portion 260c of the diaphragm valve 260 is easily deformed, it is formed in an arc shape so that stress is not concentrated. The diaphragm valve 260 is also formed with a bead portion 260d concentrically at a portion that is in contact with the flow path constituting plate 77 on the side opposite to the undercut portion 260a.

  In the passive valve configured in this way, the valve holding member 303 is urged by the spring 304 in a direction away from the stepping motor 301. Therefore, when the valve holding member 303 is operating in a linear motion, the slope of the screw portion of the lead screw 302 on the stepping motor 301 side and the slope of the female screw 303a of the valve holding member 303 on the opposite side to the stepping motor 301 side are in contact. In other words, the lead screw 302 and the valve holding member 303 are kept engaged. On the other hand, when the hole 277 is closed by the diaphragm valve 260, the biasing force of the spring 304 and the reaction force received by the diaphragm valve 260 from the flow path component plate 77 are balanced, and the thread portion of the lead screw 202 is A state in which the slope opposite to the stepping motor 301 side and the slope on the stepping motor 301 side of the female screw 303a of the valve holding member 303 are not in contact, that is, the lead screw 302 and the valve holding member 303 are in play. The diaphragm valve 260 is urged in a direction to close the hole 277 by the spring 304 while being kept in the disengaged state. Therefore, the hole 277 can be reliably closed.

[Another specific configuration example of the active valve]
With reference to FIG. 3 and FIG. 10, another specific configuration example of the active valve used as the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo in the metering pump device of this embodiment will be described.

  FIG. 9 is an explanatory diagram of the active valve used as the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo in the metering pump device 1 to which the present invention is applied, as viewed obliquely from above. As shown in FIGS. 3 and 9, the active valve used as the inflow side valves 11Ai and 11Bi and the outflow side valves 11Ao and 11Bo includes a linear actuator 201 in the hole 765 of the base plate 76. Includes a cylindrical fixed body 203 and a substantially columnar movable body 205 disposed inside the fixed body 203. The fixed body 203 includes a coil 233 that is wound around the bobbin 231 in an annular shape, and wraps around both sides in the axial direction of the coil 233 from the outer peripheral surface of the coil 233 so that one tip portion 236a and the other tip portion 236b of the coil 233 The fixed body side yoke 235 which opposes in an axial direction through the slit 237 on the inner peripheral side is provided. The movable body 205 includes a disk-shaped first movable body side yoke 251 and a pair of magnets 253a and 253b stacked on both sides in the axial direction with respect to the first movable body side yoke 251. As the pair of magnets 253a and 253b, Nd—Fe—B or Sm—Co rare earth magnets or resin magnets can be used. Further, in the movable body 205, the second movable body side yokes 255a and 255b are laminated on the end surface opposite to the first movable body side yoke 251 in each of the pair of magnets 253a and 253b.

  Each of the pair of magnets 253a and 253b is magnetized in the axial direction, and has the same polarity toward the first movable body side yoke 251. Hereinafter, in this embodiment, the pair of magnets 253a and 253b will be described as having the N pole facing the first movable body side yoke 251 and the S pole facing the outside in the axial direction. Vice versa.

  Here, the outer peripheral surface of the first movable body side yoke 251 projects from the outer peripheral surface of the pair of magnets 253a and 253b to the outer peripheral side. Further, the outer peripheral surfaces of the second movable body side yokes 255a and 255b also protrude from the outer peripheral surfaces of the pair of magnets 253a and 253b to the outer peripheral side.

  The first movable body side yoke 251 has recesses on both end surfaces in the axial direction, and a pair of magnets 253a and 253b are fitted into these recesses and fixed with an adhesive or the like. Note that the first movable body side yoke 251, the pair of magnets 253a, 253b, and the second movable body side yokes 255a, 255b can be fixed by bonding, press-fitting, or by combining them together. Good.

  Bearing plates 271a and 271b (bearing members) are fixed to openings on both sides in the axial direction of the fixed body 203, and support shafts 257a projecting from the second movable body side yokes 255a and 255b to both sides in the axial direction. 257b is slidably inserted into the holes of the bearing plates 271a and 271b. In this way, the movable body 205 is supported by the fixed body 203 so as to be capable of reciprocating in the axial direction. In this state, the movable body 205 has an outer peripheral surface facing the inner peripheral surface of the fixed body 203 via a predetermined gap, and the distal end portions 236a and 236b of the fixed body side yoke 235 are the first movable body side yoke. In the gap between the outer peripheral surface of 251 and the inner peripheral surface of the coil 233, it is in a state of facing in the axial direction. A gap is secured between the movable body 205 and the fixed body side yoke 235. For fixing the second movable body side yokes 255a and 255b and the support shafts 257a and 257b, a configuration in which they are integrated by bonding, press-fitting, or a combination thereof may be adopted.

  In the linear actuator 201 configured as described above, in this embodiment, a shaft body 259 is connected to the tip of one support shaft 257b, and the diaphragm valve 260 disposed in the valve chamber 270 is connected to the shaft body 259. The central part is connected. An annular thick portion 261 that functions as liquid tightness and positioning is formed on the outer peripheral side of the diaphragm valve 260. In the diaphragm valve 260, the outer peripheral side including the annular thick portion 261 is the base plate 76 and the flow path configuration. Liquid tightness is ensured by being sandwiched between the plates 77.

  In the linear actuator 201 configured as described above, a period in which a current flows from the far side to the near side on the right side in the drawing and a current flows in the coil 33 from the near side to the far side on the left side in the drawing. Then, as indicated by an arrow A, the movable body 205 moves by receiving a thrust in the axial direction by the Lorentz force. As a result, the hole 277 constituting the middle part of the flow path is closed and the flow path is blocked. On the other hand, when the energization direction to the coil 233 is reversed, the movable body 205 descends along the axial direction as shown by the arrow B, and opens the hole 277 constituting the middle portion of the flow path.

  In the linear actuator 201 of this embodiment, the movable body 205 is propelled by a magnetic force, and on one side in the axial direction, a truncated cone as a biasing member is provided between the bearing plate 271a and the second movable body side yoke 255a. A coil spring 291 having a shape is arranged. Therefore, when the movable body 205 descends, it moves while deforming the compression spring, and when the movable body 205 rises, it moves at high speed with the help of the shape return force of the compression spring.

  In addition, about a valve body, you may use not only the diaphragm valve 260 but a bellows valve and another valve body. Further, the support shafts 257a and 257b and the valve body may be configured as separate members, or the support shafts 257a and 257b and the valve body may be formed integrally.

  As described above, in this embodiment, in the movable body 205, the pair of magnets 253a and 253b are directed to the same pole, and a magnetic repulsive force is acting, but the first between the magnets 253a and 253b. Since the movable body side yoke 251 is disposed, the pair of magnets 253a and 253b can be fixed with the same poles directed.

  Further, in the movable body 205, the pair of magnets 253a and 253b have the same polarity directed to the first movable body side yoke 251, and thus a strong magnetic flux is generated in the radial direction from the first movable body side yoke 251. Therefore, if the peripheral surfaces of the first movable body side yoke 251 and the coil 233 are opposed to each other, a large thrust can be applied to the movable body 205.

  Furthermore, since the magnets 253a and 253b may be magnetized in the axial direction, unlike the case where the magnets 253a and 253b are magnetized in the radial direction, the magnets can be easily magnetized even when downsized, and are suitable for mass production. .

  In addition, in this embodiment, since the outer peripheral surface of the first movable body side yoke 251 protrudes from the outer peripheral surface of the pair of magnets 253a and 253b to the outer peripheral side, even when the fixed body side yoke 235 is provided, On the other hand, the magnetic attractive force acting in the direction perpendicular to the axial direction can be reduced. Similarly, since the outer peripheral surface of the second movable body side yoke 255a, 255b projects outward from the outer peripheral surface of the pair of magnets 253a, 253b, even when the fixed body side yoke 235 is provided, Thus, the magnetic attractive force acting in the direction perpendicular to the axial direction can be reduced. Therefore, there is an advantage that the assembly work is easy to perform and the movable body 205 is not easily tilted.

  Further, in this embodiment, since the magnets 253a and 253b are arranged on the outer peripheral side of the coil 33, the magnets 253a and 253b may be smaller than the case where the magnets 253a and 253b are arranged outside the coil 233. The valve can be configured at a low cost. Moreover, since the coil 233 is disposed outside, the magnetic path can be closed only by the fixed side yoke.

  Furthermore, in the fixed body 203, bearing plates 271a and 271b that support the support shafts 257a and 257b so as to be movable in the axial direction are held in the opening portion that opens in the axial direction. There is no. Further, since the bearing plates 271a and 271b can be fixed on the basis of the fixed body 203, there is an advantage that the support shafts 257a and 257b do not tilt.

[Use of metering pump device]
The metering pump device 1 to which the present invention is applied is used, for example, to quantitatively supply water to reformers of various fuel cells. In addition, the metering pump device 1 to which the present invention is applied is used for the quantitative supply of aqueous urea solution to the reformer for decomposing and removing nitrogen oxides from the exhaust gas of a diesel engine, and for the delivery of drip solution. You can also. In particular, it is suitable for performing quantitative discharge in a technical field where there is a large pressure difference between the suction side and the discharge side.

[Other embodiments]
In the above embodiment, two reciprocating pump devices 10A and 10B are used. However, the present invention may be applied to a metering pump device using three or more reciprocating pump devices.

It is a conceptual diagram which shows the basic composition of the metering pump apparatus which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structural example of the metering pump apparatus shown in FIG. It is a longitudinal cross-sectional view of the main-body part of the metering pump apparatus shown in FIG. It is a timing chart figure which shows operation | movement of the metering pump apparatus to which this invention is applied. It is another timing chart figure which shows operation | movement of the metering pump apparatus to which this invention is applied. It is a conceptual diagram which shows the basic composition of the metering pump apparatus which concerns on Embodiment 2 of this invention. It is a conceptual diagram which shows the basic composition of the metering pump apparatus which concerns on Embodiment 3 of this invention. It is an exploded perspective view of the state where the reciprocating pump device used for the metering pump device to which the present invention is applied is vertically divided. It is explanatory drawing which shows the longitudinal cross-section of the active valve used as the inflow side valve | bulb and the outflow side valve | bulb in the metering pump apparatus to which this invention is applied. It is explanatory drawing when the vertical cross section of another active valve used as an inflow side valve | bulb and an outflow side valve | bulb is seen from diagonally upward in the metering pump apparatus to which this invention is applied.

Explanation of symbols

1. · Quantitative pump device 10A, 10B ·· Reciprocating pump device 11Ai, 11Bi ·· Inflow side valve 11Ao, 11Bo ·· Outlet side valve 12Ai, 12Bi, 12i・ Common discharge port 13i ・ ・ Common suction port 14A, 14B, 14o ・ ・ Pressure sensor (monitoring device)

Claims (9)

A plurality of reciprocating pump devices each having an inflow side valve and an outflow side valve connected to the inflow side and the outflow side, respectively, and a common discharge port connected to the plurality of reciprocating pump devices via the outflow side valve In the metering pump device
A controller that controls the inflow side valve, the outflow side valve, and the reciprocating pump device;
The control unit sets a discharge period and a standby period by shifting the timing for each of the plurality of reciprocating pump devices, and at the end of the discharge period of another reciprocating pump device and the start and end of the discharge period. After the start period is superimposed and the suction operation into the pump chamber is performed in the standby period, before the discharge period, both the inflow side valve and the outflow side valve are closed to expand or contract the volume in the pump chamber A metering pump device that performs a correction operation to eliminate a pressure difference between the pressure in the pump chamber and the common discharge port side.   2. The metering pump device according to claim 1, further comprising a common suction port connected to the plurality of reciprocating pump devices via the inflow side valve.   3. The metering pump device according to claim 1, wherein the reciprocating pump device has a drive source that is a stepping motor or an AC synchronous motor. The reciprocating pump device according to claim 1 or 2, wherein a driving source is a stepping motor,
A metering pump device, wherein the amount of change in the internal volume of the pump chamber corresponding to one step of the stepping motor is 1/100 or less of the internal volume of the entire pump chamber. In any one of Claims 1 thru | or 4, The monitoring apparatus which monitors the pressure difference between the pressure in the pump chamber of the said reciprocating pump apparatus and the said common discharge port directly or indirectly is provided,
The control unit causes the correction operation to be performed when there is a pressure difference between the pressure in the pump chamber and the common discharge port side based on the monitoring result of the monitoring device. .   6. The monitoring device according to claim 5, wherein the monitoring device includes a plurality of first pressure sensors that monitor pressures in the pump chambers of the plurality of reciprocating pump devices, and a second pressure sensor that monitors the pressure on the common discharge port side. A metering pump device comprising: comparing the detection results of the first pressure sensor and the second pressure sensor and monitoring the pressure difference.   6. The reciprocating pump device according to claim 5, wherein the monitoring device includes a plurality of pressure sensors that monitor pressures in the pump chambers of the plurality of reciprocating pump devices, and the reciprocating pump device that performs the suction operation among the plurality of reciprocating pump devices. The pressure difference between the detection result of the pressure sensor arranged in the pump chamber and the detection result of the pressure sensor arranged in the pump chamber of the reciprocating pump device in which the output side valve is open is compared. Metering pump device characterized by monitoring In any one of Claims 1 thru | or 7, the number of the said reciprocating pump apparatuses is two units,
The metering pump device, wherein the control device sets an expansion rate of the pump chamber when performing the suction operation to be higher than a contraction rate of the pump chamber during the discharge period. A plurality of reciprocating pump devices each having an inflow side valve and an outflow side valve connected to the inflow side and the outflow side, respectively, and a common discharge port connected to the plurality of reciprocating pump devices via the outflow side valve In the metering pump device
The metering pump device further comprises a pressure sensor for monitoring the pressure in each pump chamber of the plurality of reciprocating pump devices.

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