Pump device

Abstract

This pump device comprises: a pump head formed with a suction port and a discharge port for a transfer fluid; a diaphragm that is attached to the pump head and forms a pump chamber that provides communication between the suction port and the discharge port; a pump body including a reciprocating member connected to the diaphragm so as to be movable in the reciprocating direction of the diaphragm, a drive mechanism capable of driving the reciprocating member in the reciprocating direction of the diaphragm, and a control unit for controlling the drive mechanism; a sensor unit that is disposed in a non-contact portion of the pump device where the transfer fluid does not contact the pump device, and detects strain occurring in the non-contact portion during operation of the pump device; and an estimation unit that estimates an actual flow rate of the transfer fluid or the pressure of the transfer fluid in the pump device, on the basis of the amount of strain in the non-contact portion detected by the sensor unit.

Description

Pump equipment

[0001] The present invention relates to a pump device.

[0002] Conventionally, pump devices have been known that have a pump head attached to a pump body that houses a pump drive mechanism. For example, in pump devices that use a reciprocating member such as a diaphragm, a pressure sensor attached to the pump head or the like acquires the pressure in the pump chamber, and determines the flow rate of the transported fluid and other factors to determine the operating state. This prevents malfunctions due to, for example, the accumulation of a large amount of gas bubbles in the pump chamber (see Patent Document 1).

[0003] Patent No. 6022943

[0004] However, the pump device of the prior art disclosed in the above-mentioned Patent Document 1 employs a structure in which the pressure sensor is disposed in a position where it comes into contact with the transported fluid. Therefore, it is not suitable for transporting a transported fluid that has characteristics that would cause an expensive pressure sensor to deteriorate or malfunction. Therefore, in such a case, it is not possible to determine the flow rate of the transported fluid, and therefore it is not possible to determine the operating state of the pump device based on the determination.

[0005] On the other hand, it is also common to measure the flow rate of the transported fluid by providing a flow meter in the piping of the pump device, etc. However, in this case, there are problems such as an increase in the cost of the flow meter and restrictions on various piping conditions.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a pump device that can be constructed inexpensively and that can easily estimate the flow rate, pressure, and operating state of the pump device without being affected by the characteristics of the transported fluid or the piping conditions.

[0007] A pump device according to the present invention comprises a pump head having an inlet and an outlet for a transported fluid, a diaphragm attached to the pump head and defining a pump chamber connecting the inlet and the outlet, a reciprocating member connected to the diaphragm and movable in the reciprocating direction of the diaphragm, a drive mechanism for driving the reciprocating member in the reciprocating direction of the diaphragm, and a pump body including a control unit for controlling the drive mechanism. The pump device also comprises a sensor unit disposed in a non-contact portion of the pump device that does not come into contact with the transported fluid and that detects strain generated in the non-contact portion during operation of the pump device, and an estimation unit that estimates an actual flow rate or pressure of the transported fluid in the pump device based on the amount of strain in the non-contact portion detected by the sensor unit.

[0008] In one embodiment of the present invention, the control unit controls the operation of the drive mechanism based on the estimation result of the actual flow rate by the estimating unit so that the actual flow rate of the transport fluid becomes a preset set flow rate.

[0009] In another embodiment of the present invention, the apparatus further includes a memory unit that stores information that indicates a ratio of an actual flow rate to a potential difference of waveform data that represents the amount of strain for each stroke number of the reciprocating member, the information being created in advance, and the estimation unit estimates the actual flow rate from the potential difference of the waveform data that represents the amount of strain by referring to the information that indicates the actual flow rate ratio stored in the memory unit.

[0010] In yet another embodiment of the present invention, the control unit further includes a display unit that visibly displays information about the estimated actual flow rate together with a set flow rate.

[0011] In yet another embodiment of the present invention, the estimation unit estimates that the operating state of the pump device is abnormal if the output value of the waveform data representing the amount of distortion after a predetermined time has elapsed from the start timing of the suction period of the pump device is greater than a predetermined threshold value, or if the output value of the waveform data representing the amount of distortion after a predetermined time has elapsed from the start timing of the discharge period of the pump device is smaller than a predetermined threshold value.

[0012] In yet another embodiment of the present invention, the sensor portion is disposed in the non-contact portion on the outer periphery of the reciprocating member near a connection portion with the diaphragm.

[0013] In yet another embodiment of the present invention, a plurality of the sensor units are arranged in the non-contact area.

[0014] In yet another embodiment of the present invention, the sensor unit is arranged in the non-contact portion of at least one of a reinforcing member attached to the front side of the pump head, a retainer member arranged on the back side of the diaphragm, a bracket member attached to the front side of the drive mechanism, an outer periphery of the reciprocating member located rearward of the front side of the bracket member, and the upper part of the drive mechanism.

[0015] According to the present invention, it is possible to easily estimate the flow rate, pressure, and operating state of a pump device, which can be constructed inexpensively and is not affected by the characteristics of the transported fluid or the piping conditions.

[0016] FIG. 1 is a side cross-sectional view schematically showing a pump device according to a first embodiment of the present invention. FIG. 2 is a view taken along arrow A in FIG. 1. FIG. 3 is a block diagram schematically showing a circuit configuration of the pump device. FIG. 4 is a graph illustrating an example of an estimated flow rate and an actually measured flow rate of the pump device. FIG. 5 is a graph illustrating an example of an estimated flow rate and an actually measured flow rate of the pump device. FIG. 6 is a graph illustrating an example of waveform data of a suction period and a discharge period of the pump device and the amount of strain. FIG. 7 is a diagram showing an example of data stored in a memory unit of the pump device. FIG. 8 is a diagram showing an example of a display on a display unit of the pump device. FIG. 9 is a cross-sectional view schematically showing an arrangement position of a sensor unit in a pump device according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view schematically showing an arrangement position of a sensor unit in a pump device according to a third embodiment of the present invention. FIG. 12 is a cross-sectional view schematically showing an arrangement position of a sensor unit in a pump device according to a fourth embodiment of the present invention. FIG. 13 is a cross-sectional view schematically showing an arrangement position of a sensor unit in a pump device according to a fifth embodiment of the present invention. FIG. 14 is a cross-sectional view schematically showing an arrangement position of a sensor unit in a pump device according to a sixth embodiment of the present invention.

[0017] Hereinafter, pump devices according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments do not limit the invention according to each claim, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0018] In the following embodiments, the same or corresponding components are denoted by the same reference numerals, and redundant explanations are omitted. In the embodiments, the arrangement, scale, dimensions, etc. of each component may be exaggerated or minimized, and may not correspond to the actual ones, and some components may be omitted.

[0019] [First embodiment] [Configuration of pump device] Fig. 1 is a side cross-sectional view schematically showing a pump device according to a first embodiment of the present invention. Fig. 2 is a view taken along the arrow A in Fig. 1. Fig. 3 is a block diagram schematically showing the circuit configuration of the pump device.

[0020] 1, the pump device 100 of the first embodiment includes a pump body 20 having a drive mechanism 10, which is a drive source (drive unit), and a control board 29, and a pump head 30 attached to the front side of the pump body 20. The basic configuration of the pump device 100 of this embodiment, including its internal structure, can be configured as that of a so-called general pump device. Therefore, the following description will be limited to a summary, avoiding detailed description of known configurations.

[0021] The pump device 100 also includes an adapter member 40 disposed between the pump head 30 and the pump body 20 to attach the pump head 30 to the pump body 20. The pump device 100 includes a diaphragm 50 that is attached to the pump head 30 by being sandwiched between the adapter member 40 and the diaphragm 50, and that is connected via the adapter member 40 to the shaft member 11, which is the reciprocating member of the drive mechanism 10.

[0022] Furthermore, the pump device 100 has a strain gauge 16 as a sensor located at a position of the pump device 100 that does not come into contact with the transported fluid. Hereinafter, the direction of the pump body 20 toward the pump head 30 will be referred to as the "front," and the direction opposite thereto will be referred to as the "rear." As shown by the arrows in Figure 1, the direction of movement of the diaphragm 50 and the shaft member 11 forward and backward will be referred to as the "reciprocating direction RD."

[0023] [Configuration of Drive Mechanism] The drive mechanism 10 includes, for example, a motor 12, an eccentric cam mechanism 13, and a shaft member 11. The motor 12 rotates and drives a rotating shaft 13a of the eccentric cam mechanism 13 via a gear mechanism 12a. The eccentric cam mechanism 13 converts the rotational motion of the rotating shaft 13a into reciprocating motion of the shaft member 11 by an eccentric cam portion 13b. The shaft member 11 is driven in forward and backward reciprocating directions RD by the reciprocating motion converted by the eccentric cam mechanism 13.

[0024] The shaft member 11 is made of, for example, a rod-shaped metal or resin member. The shaft member 11 has, for example, a first member 11a disposed on the front side so as to be connected to the diaphragm 50, and a second member 11b disposed on the rear side of the first member 11a and connected to the eccentric cam portion 13b of the eccentric cam mechanism 13.

[0025] The shaft member 11 is pushed forward by the eccentric cam portion 13b. At the same time, the front flange portion 11c of the second member 11b of the shaft member 11 is pressed forward by the repulsive force of the spring member 14. As a result, the shaft member 11 moves toward the front side of the pump body 20, displacing the diaphragm 50 in an advance direction. Furthermore, the front flange portion 11c of the second member 11b is pulled back toward the rear side by the eccentric cam portion 13b with a force stronger than the repulsive force of the spring member 14, causing the shaft member 11 to move toward the rear side of the pump body 20. As a result, the shaft member 11 displaces the diaphragm 50 in a retreat direction.

[0026] In this way, the shaft member 11 is pushed and pulled by the eccentric cam portion 13b in the drive mechanism 10, and thereby repeats the forward and backward movements described above, thereby reciprocating in the reciprocating direction RD. Note that a bracket portion 15, which is a bracket member facing the front opening 20a of the pump body 20, is provided on the front side (front surface) of the drive mechanism 10 to attach an adapter member 40 (described later).

[0027] Furthermore, the drive mechanism 10 is not limited to the configuration including the motor 12 and eccentric cam mechanism 13, as long as it is configured to be able to drive the shaft member 11 at least in the direction in which the diaphragm 50 advances or retreats as described above. The drive mechanism 10 may be configured to employ, for example, an actuator or the like that linearly moves the shaft member 11 by, for example, electromagnetic force or the like.

[0028] [Configuration of Pump Body] The housing portion constituting the pump body 20 is made of, for example, a resin material. That is, the pump body 20 has a front housing 26, a rear housing 27 connected thereto, and a pump base 20b. The front housing 26 has a front opening 20a provided on the front side, and an accommodation space 21 connected to the front opening 20a provided above the pump base 20b. The rear housing 27 has an accommodation space 25 capable of accommodating a control board 29.

[0029] The accommodation space 21 in the front housing 26 of the pump body 20 is formed, for example, in a cylindrical shape. A portion (e.g., a lower side) of the accommodation space 21 in the pump body 20 is configured to be connected to the interior of the pump base 20b. The accommodation space 25 in the rear housing 27 of the pump body 20 is formed in the same shape as the accommodation space 21 or in a rounded rectangular shape, while being isolated from the accommodation space 21 in the reciprocating direction RD. The accommodation space 25 of the pump body 20 is configured in such a way that a portion (e.g., a lower side) of the accommodation space 25 is connected to the interior of the pump base 20b.

[0030] The housing space 21 of the front housing 26 mainly accommodates the drive mechanism 10, a wiring tube 19a that houses, for example, a cable 19 as wiring and that is routed around the drive mechanism 10, and the above-mentioned bracket portion 15. The front housing 26 has a rear wall 22 provided on the rear side. A rear housing 27 is attached to a back surface (rear surface) 22a of the rear wall 22 of the front housing 26 by means of mounting screws 27a.

[0031] The control board 29 is directly attached to the rear housing 27 by using mounting screws 27b. The cable 19 of the wiring tube 19a is connected to the control board 29. The control board 29 controls the drive mechanism 10, and thereby controls the overall operation of the pump device 100.

[0032] An operation unit 28 is provided on the rear side of the pump body 20 to allow an operator to input operations such as setting operations for the pump device 100. The operation unit 28 includes a display unit 28a that visibly displays various information related to the pump device 100.

[0033] [Arrangement of Sensor Unit] The strain gauge 16, which is the sensor unit, is arranged in a non-contact position with the transported fluid, for example, on the outer periphery of the first member 11a of the shaft member 11 near the connection with the diaphragm 50. The strain gauge 16 detects strain occurring on the outer periphery of the first member 11a when the pump device 100 is operating.

[0034] 2, the strain gauge 16 is attached to the outer periphery of the first member 11a with an adhesive or the like. However, the arrangement of the strain gauge 16 is not limited to this. The strain gauge 16 may be arranged singly on the outer periphery of the first member 11a as shown in the figure, but in this embodiment, a plurality of strain gauges (for example, two) are arranged on the outer periphery of the first member 11a, although this is not shown in the figure.

[0035] A lead wire 16a is connected to the strain gauge 16 so as to extend in a direction intersecting the reciprocating direction RD. The lead wire 16a extending from the strain gauge 16 is protected by a protective measure, such as a silicone coating. A connector 16b is connected to the end of the lead wire 16a. The connector 16b is connected to a relay connector 16c provided on a part of the bracket portion 15. The relay connector 16c is connected to a sensor board 29a disposed, for example, on the upper part of the drive mechanism 10, via a cable 19b and a connector 16d. The sensor board 29a is connected to the cable 19 via a connector 16e. As a result, the strain gauge 16 is electrically connected to the control board 29 via the lead wire 16a, connector 16b, relay connector 16c, cable 19b, connector 16d, sensor board 29a, connector 16e, and cable 19.

[0036] [Configuration of Pump Head] The pump head 30 is made of, for example, a resin material or a metal material such as stainless steel. The pump head 30 has a pump chamber 31 formed in its center. The pump chamber 31 is formed together with a diaphragm 50 attached to the pump head 30, and its volume changes in response to the displacement of the diaphragm 50. In the pump device 100 of this embodiment, a reinforcing plate 30a, which is a reinforcing member for reinforcing the mechanical strength of the pump head 30, and a cover member 30b for protecting the reinforcing plate 30a are attached to the front side of the pump head 30.

[0037] The pump head 30 is attached to the front opening 20a side of the front housing 26 via, for example, an adapter member 40 attached to the bracket 15 of the drive mechanism 10. The pump head 30 has a suction port 32 and a discharge port 33 for the transport fluid that communicate with the pump chamber 31. The suction port 32 communicates, for example, with a lower part of the pump chamber 31. The discharge port 33 communicates, for example, with an upper part of the pump chamber 31.

[0038] The pump head 30 is formed with a first connection port 34 on the suction side of the transferred fluid, located below the suction port 32. The pump head 30 also is formed with a second connection port 35 on the discharge side of the transferred fluid, located above the discharge port 33. The first connection port 34 and the second connection port 35 are connected to the pump chamber 31 via the suction port 32 and the discharge port 33, respectively.

[0039] A cylindrical suction side adapter 37, with an suction valve 36a installed, is connected to the first connection port 34 by a connecting nut 37a. A cylindrical discharge side adapter 38, with an discharge valve 36b installed, is connected to the second connection port 35 by a connecting nut 37b.

[0040] The suction-side adapter 37 is connected to a suction-side pipe (not shown) and connects the suction port 32 of the pump head 30 to a suction-side flow path 39a via a suction valve 36a. The discharge-side adapter 38 is connected to a discharge-side pipe (not shown) and connects the discharge port 33 of the pump head 30 to a discharge-side flow path 39b via a discharge valve 36b.

[0041] [Configuration of Adapter Member] The adapter member 40 is made of, for example, a resin member. The adapter member 40 is disposed between the pump head 30 and the pump body 20 (the front opening 20a of the front housing 26). As a result, the adapter member 40 closes the front opening 20a, closing the accommodation space 21. The adapter member 40 has, for example, a plurality of mounting holes (not shown) arranged at a predetermined pitch, and a plurality of insertion holes (not shown) arranged at a different predetermined pitch from the plurality of mounting holes.

[0042] The adapter member 40 is fastened to the bracket portion 15 by fastening means such as bolts (not shown) inserted into the mounting holes. In this way, the adapter member 40 is attached to the pump body 20 so as to close the front opening 20a of the front housing 26. The pump head 30 is liquid-tightly attached to the front side of the pump body 20 via the adapter member 40 by fastening, for example, bolts 42a that pass through the insertion holes of the reinforcing plate 30a and the adapter member 40 to the bracket portion 15 located behind the adapter member 40.

[0043] The adapter member 40 has, for example, an annular protrusion 43 that sandwiches the fixing portion 51 located on the outer periphery of the diaphragm 50 together with the pump head 30, and a wall portion 44 that is continuous with the inner circumferential wall surface 43a of the annular protrusion 43. A circular central hole 46 is formed in the center of the wall portion 44 of the adapter member 40.

[0044] A gasket member 60 is attached to the rear surface (the surface facing the front housing 26) of the wall portion 44 of the adapter member 40 in a state where it is sandwiched between the bracket portion 15 and the adapter member 40. The gasket member 60 is made of, for example, rubber. The gasket member 60 has a disk portion 61 that contacts the rear surface of the wall portion 44, and a central protrusion 62 that is provided in the center of the disk portion 61 and has an uneven shape in the reciprocating direction RD (a bellows shape in a direction intersecting the reciprocating direction RD).

[0045] The central protrusion 62 of the gasket member 60 is liquid-tightly inserted into the central hole 46 of the wall portion 44 of the adapter member 40. Furthermore, the first member 11a of the shaft member 11 is liquid-tightly inserted into the central hole 63 of the central protrusion 62. Therefore, the outer periphery of the first member 11a of the shaft member 11, on which the strain gauge 16 is disposed, is positioned rearward of the central hole 63 of the central protrusion 62 of the gasket member 60. As a result, the outer periphery of the first member 11a does not come into contact with the transport fluid flowing through the suction port 32, the pump chamber 31, and the discharge port 33, and is positioned in a non-contact state.

[0046] [Configuration of Diaphragm] The diaphragm 50 is connected via an insert bolt 52 to the first member 11a of the shaft member 11, which is inserted into the central hole 63 of the central protrusion 62 of the gasket member 60. The diaphragm 50 is an elastic member formed by integrally molding the insert bolt 52, which is connected to the first member 11a, inside a resin such as ethylene propylene rubber (EPDM) or polytetrafluoroethylene (PTFE).

[0047] The diaphragm 50 is driven by the drive mechanism 10 housed in the front housing 26 of the pump body 20 to displace in the reciprocating direction RD so as to change the volume of the pump chamber 31 of the pump head 30. As described above, the fixed portion 51 of the diaphragm 50 is sandwiched between the pump head 30 and the annular protrusion 43 of the adapter member 40. The diaphragm 50 is attached in a liquid-tight manner with the front side of its central portion 53 facing the pump chamber 31. Note that a retainer member 54, for example, is disposed between the diaphragm 50 and the tip of the first member 11a of the shaft member 11 to maintain the shape and position of the diaphragm 50.

[0048] In the pump device 100 configured in this manner, if it becomes necessary to replace the strain gauge 16, for example, the pump head 30, diaphragm 50, and adapter member 40 are removed from the pump body 20. Then, the connector 16b is disconnected from the relay connector 16c, and the strain gauge 16 can be replaced together with the first member 11a of the shaft member 11. This realizes a structure that facilitates the replacement of the strain gauge 16 and maintenance of the pump head 30.

[0049] 3, the circuit configuration of the pump device includes a plurality of strain gauges 16 (resistors R1, R2), a sensor board 29a, and a control board 29. The sensor board 29a includes resistors R3 and R4 that form a bridge circuit 71 together with the plurality of strain gauges 16 (resistors R1, R2), and a differential amplifier circuit 72 that includes an operational amplifier 72a and a plurality of resistors R5, R6, R7, and R8 connected thereto. The control board 29 includes a control unit 73, an estimation unit 74, and a memory unit 75.

[0050] The circuits 71 and 72 of the sensor board 29a are designed as appropriate to suit various data and conditions, such as the main specifications of the pump device 100. The sections 73 to 75 of the control board 29 are configured as appropriate by combining known hardware, such as a CPU, RAM, and ROM.

[0051] The bridge circuit 71 includes a strain gauge 16 as a resistor R1 and a strain gauge 16 as a resistor R2 arranged on adjacent sides of the bridge, and two fixed resistors R3 and R4. The bridge circuit 71 is configured to be able to reduce apparent strain due to temperature.

[0052] The differential amplifier circuit 72 appropriately adjusts the values ​​of the four resistors R5 to R8 connected to the operational amplifier 72a, thereby amplifying the output (strain detection signal) from the bridge circuit 71 to a predetermined value, eliminating noise and providing temperature compensation.

[0053] Therefore, the detection signal of the strain gauge 16 output from the bridge circuit 71 during operation of the pump device 100 is temperature compensated and then amplified and noise-removed in the differential amplifier circuit 72. The detection signal can then be input to the estimation unit 74 as waveform data representing the amount of strain in the outer circumferential portion of the first member 11a of the shaft member 11.

[0054] The estimation unit 74 estimates the flow rate or pressure of the transported fluid in the pump device 100 based on the input waveform data. That is, the flow rate and pressure of the transported fluid in the pump device 100 fluctuate depending on the load. Pressure changes inside the pump head 30 (e.g., inside the pump chamber 31) that occur during operation of the pump device 100 are applied as load changes to the shaft member 11 via the diaphragm 50. This generates strain proportional to the load.

[0055] By detecting this generated strain using the strain gauge 16, the estimation unit 74 estimates the flow rate or pressure of the transported fluid in the pump device 100 based on waveform data representing the amount of strain output via the bridge circuit 71 and the differential amplifier circuit 72.

[0056] Meanwhile, the control unit 73 controls the operation of the drive mechanism 10 so that the actual flow rate (actual flow rate) of the transport fluid becomes, for example, a preset set flow rate, based on the flow rate estimation result by the estimating unit 74. The storage unit 75 stores information (actual flow rate ratio data) relating to the flow rate reduction rate or actual flow rate ratio with respect to the potential difference of waveform data representing the strain amount for each stroke number (spm: strokes per minute) of the shaft member 11, which has been created by performing measurements or the like in advance. The estimating unit 74 estimates the actual flow rate of the pump device 100 by referring to the actual flow rate ratio data stored in the storage unit 75.

[0057] Furthermore, when gas is sucked into the pump chamber 31 during gas inhalation, the gas is compressed, which delays the rise of the waveform data representing the amount of strain. For this reason, the estimation unit 74 grasps the gas inhalation state by setting a threshold value for the output value after a certain time has elapsed (after a predetermined time has elapsed) from the rise of the waveform data.

[0058] In this way, the estimating unit 74 can further estimate the operating state of the pump device 100, such as the extent to which the actual flow rate is relative to the set flow rate, or whether the pump device 100 is operating abnormally, based on the estimated actual flow rate. The control unit 73 then performs a flow rate correction calculation based on the actual flow rate estimation result by the estimating unit 74, for example, using the actual flow rate ratio data, etc., to adjust the actual flow rate of the transported fluid to the set flow rate. The control unit 73 can then operate the drive mechanism 10 to correct the flow rate. The display unit 28a of the operating unit 28 can display notification information regarding the operating state of the pump device 100 estimated by the estimating unit 74 in a manner that is visible to the operator.

[0059] Figures 4 and 5 are graphs illustrating the estimated flow rate of the pump device 100 and the actual measured flow rate, where Figure 4 sets the set flow rate to 60 [L / H] and Figure 5 sets the set flow rate to 1.0 [L / H], and the vertical axis represents the flow rate [L / H] and the horizontal axis represents the pressure [MPa].

[0060] As shown in graph 77a of FIG. 4 and graph 77b of FIG. 5, whether the set flow rate is 60 [L / H] or 1.0 [L / H], the flow rate tends to decrease as the pump pressure increases. The approximate curve 77c of the estimated flow rate, shown by the dashed line in the figure, is plotted to have a shape similar to the approximate curve 77d of the measured flow rate, shown by the solid line in the figure. A comparison of the estimated flow rate thus plotted with the measured flow rate was performed, and the error of the estimated flow rate relative to the measured flow rate was within ±2.08 [%RS] in terms of lead scale accuracy. Therefore, it was found that the estimator 74 can estimate the flow rate with high accuracy. As mentioned above, the pump pressure has a significant correlation with the amount of strain.

[0061] Fig. 6 is a graph illustrating waveform data of the suction period and discharge period of the pump device 100 and the amount of strain. Fig. 7 is a diagram showing an example of data stored in the storage unit 75 of the pump device 100, and shows an example of actual flow rate ratio data indicating a flow rate reduction rate that has been measured in advance in the pump device 100 connected under predetermined piping conditions.

[0062] As shown in FIG. 6 , the high-level square wave U represents the suction period during which the pump device 100 is sucking in the transported fluid. The low-level square wave D represents the discharge period during which the pump device 100 is discharging the transported fluid. This can be obtained, for example, from a sensor cam signal (not shown). Meanwhile, the waveform data W represents the output waveform of the differential amplifier circuit 72. The waveform data W represents, for example, the amount of strain detected by the strain gauge 16 as a change in stress on the shaft member 11 of the pump device 100. Therefore, the higher the level of the waveform data W, the greater the load on the shaft member 11 (the higher the load on the pump device 100). The waveform data W has the characteristic that its shape and level change depending on the pressure value of the transported fluid.

[0063] 6, it can be seen that during the suction period of the transferred fluid represented by the square wave U, the shaft member 11 is pulled back and the load on the shaft member 11 decreases, so the waveform data W drops sharply and the level decreases. On the other hand, during the discharge period of the transferred fluid represented by the square wave D, the shaft member 11 is pushed forward and the load on the shaft member 11 increases over time, so the waveform data W rises more gradually than when it drops as described above, and the level increases.

[0064] Then, the potential difference PD of the drive mechanism 10, which is represented by, for example, the level position D1 of the waveform data W at the end of one period of the square wave D and the level position D2 of the waveform data W at the start of the next period of the square wave D, is estimated and obtained from the waveform data W. This makes it possible to recognize the pressure of the transported fluid as the potential difference PD. In this embodiment, the "potential difference [V] of the waveform data representing the amount of strain," which is an input variable of the estimation unit 74, is set to the average value of the potential differences PD of three samples to eliminate the influence of noise. However, the number of samples used to calculate the average value may be greater or less.

[0065] 7, the row elements represent, for example, a plurality of potential differences [V] calculated from three sample potential differences PD under a single operating condition (stroke count). Also, in the actual flow rate ratio data 78, the column elements represent, for example, a plurality of stroke counts [spm] set at nine resolutions, and the corresponding numerical values ​​of the flow rate reduction rates are associated with these.

[0066] The stroke rate [spm] corresponds to the set flow rate [L / H]. In this example, the stroke rates [spm] of 0.9 to 3.6, 3.6 to 9.0, 9.0 to 18.0, 18.0 to 36.0, 36.0 to 72.0, 72.0 to 108, 108 to 144, 144 to 180, and 180 or higher correspond to the set flow rates [L / H] of 0.3 to 1.2, 1.2 to 3.0, 3.0 to 6.0, 6.0 to 12.0, 12.0 to 24.0, 24.0 to 36.0, 36.0 to 48.0, 48.0 to 60.0, and 60.0 or higher, respectively.

[0067] As shown in FIG. 7, according to the actual flow rate ratio data 78 indicating the flow rate reduction rate, for example, when the potential difference [V] is greater than 0.10 and less than 0.35, the flow rate reduction rate is 0.00 (%) regardless of whether the stroke count [spm] is 0.9 to 180, and therefore it can be estimated that the actual flow rate remains the set flow rate.

[0068] On the other hand, as the potential difference [V] gradually increases from 0.35 to 0.60, 0.60 to 0.85, ..., and greater than 2.70, the flow rate reduction rate at each stroke rate [spm] decreases. The largest flow rate reduction rate is in the range greater than the maximum stroke rate [spm] of 180, at which point the flow rate reduction rate is 23.68%.

[0069] The estimation unit 74 then inputs the input variables, the potential difference [V] and the flow rate setting value [L / H] (set stroke number [spm]), and estimates the actual flow rate based on a table such as that shown in Figure 7 stored in the memory unit 75.

[0070] 8 is a diagram showing an example of a display on the display unit of the pump device. As shown in Fig. 8, the display unit 28a included in the operation unit 28 has a first flow rate display area 28b that displays, for example, the flow rate estimated by the estimator 74 as described above (and the actual flow rate calculated by calculation), and a second flow rate display area 28c that displays a set flow rate that has been set in advance by an operator or the like. By displaying the estimated flow rate and the set flow rate side by side in an easily visible manner on the display unit 28a, the operator can easily grasp the operating state of the pump device 100.

[0071] In addition, the estimation unit 74 can perform calculations, for example, to multiply the stroke count [spm] by adding 100 to the flow rate reduction rate (flow rate reduction rate + 100 (%)), correct the flow rate that has decreased from the set flow rate, and have the control unit 73 control the operation of the drive mechanism 10 so that the set flow rate is reached again.

[0072] As described above, the estimation unit 74 detects the pressure of the transported fluid from the waveform data representing the strain amount, and estimates that the operating state of the pump device 100 is abnormal when, for example, the output value of the waveform data representing the strain amount after a certain time has elapsed since the start of the suction period of the pump device 100 is greater than a predetermined threshold, or when the output value of the waveform data representing the strain amount after a certain time has elapsed since the start of the discharge period of the pump device 100 is smaller than a predetermined threshold. The estimation unit 74 may also focus on, for example, whether the waveform shape of the waveform data from the rising point to the peak point is delayed compared to normal operation. If the waveform shape indicates an operating state such as a special shape that is significantly delayed from the start of the discharge period, as indicated by the square wave D, compared to normal operation, it may also be estimated that a gas intake state has occurred and that the operating state of the pump device 100 is abnormal. In these cases, it is possible to display notification information to that effect on the display unit 28a.

[0073] In this way, the pump device 100 according to this embodiment can estimate the flow rate and pressure of the transported fluid in the pump device 100 based on the amount of strain of the shaft member 11 detected by the strain gauge 16. This allows for an inexpensive configuration, and makes it possible to easily estimate the flow rate and operating state without being affected by the characteristics of the transported fluid or the piping conditions, and also makes it easy to correct the flow rate and estimate abnormal operation.

[0074] 9 is a cross-sectional view showing the layout of a sensor unit in a pump device according to a second embodiment of the present invention. Hereinafter, explanations that overlap with those already explained will be omitted.

[0075] 9, the pump device 100A according to the second embodiment differs from the first embodiment in that a strain gauge 16, which serves as a sensor, is disposed on the front surface 30c of a reinforcing plate 30a attached to the front surface of a pump head 30, which is a portion that does not come into contact with the transported fluid. Even with this configuration, the load on the pump device 100A can be detected as strain by the strain gauge 16, and therefore the same effects as those of the first embodiment can be achieved.

[0076] Third Embodiment FIG. 10 is a cross-sectional view schematically showing the arrangement position of a sensor unit in a pump device according to a third embodiment of the present invention.

[0077] 10, the pump device 100B according to the third embodiment differs from the first and second embodiments in that a strain gauge 16, which serves as a sensor, is disposed on the rear surface (rear surface) 54a of a retainer member 54, which is disposed on the rear side (rear side) of a diaphragm 50, which is a non-contact portion of the pump device 100B. Even with this configuration, the load on the pump device 100B can be detected as strain by the strain gauge 16, and therefore the same effects as those of the first and second embodiments can be achieved.

[0078] Fourth Embodiment FIG. 11 is a cross-sectional view schematically showing the arrangement position of a sensor unit in a pump device according to a fourth embodiment of the present invention.

[0079] 11, the pump device 100C according to the fourth embodiment differs from the first to third embodiments in that a strain gauge 16, which serves as a sensor, is disposed on the rear surface 15a of a bracket 15 attached to the front surface of the drive mechanism 10, which is a portion that does not come into contact with the transported fluid. Even with this configuration, the load on the pump device 100C can be detected as strain by the strain gauge 16, and therefore the same effects as those of the first to third embodiments can be achieved.

[0080] Fifth Embodiment FIG. 12 is a cross-sectional view schematically showing the arrangement position of a sensor unit in a pump device according to a fifth embodiment of the present invention.

[0081] 12, the pump device 100D according to the fifth embodiment differs from the first to fourth embodiments in that a strain gauge 16, which serves as a sensor, is disposed on the outer periphery of the second member 11b of the shaft member 11, which is located rearward of the front surface of the bracket portion 15, which is a non-contact portion of the transported fluid. Even with this configuration, the load on the pump device 100D can be detected as strain by the strain gauge 16, and therefore the same effects as those of the first to fourth embodiments can be achieved.

[0082] Sixth Embodiment FIG. 13 is a cross-sectional view schematically showing the arrangement position of a sensor unit in a pump device according to a sixth embodiment of the present invention.

[0083] 13, the pump device 100E according to the sixth embodiment differs from the first to fifth embodiments in that a strain gauge 16, which serves as a sensor, is disposed on the upper portion of the drive mechanism 10, which is a portion that does not come into contact with the transported fluid (for example, on the upper surface 13d of the bearing portion 13c of the eccentric cam mechanism 13). Even with this configuration, the load on the pump device 100E can be detected as a strain amount by the strain gauge 16, and therefore the same effects as those of the first to fifth embodiments can be achieved.

[0084] 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 embodied 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 modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0085] For example, in the first embodiment described above, the strain gauge 16 is disposed on the outer periphery of the first member 11a of the shaft member 11, and in the second to sixth embodiments, the strain gauge 16 is disposed in a non-contact portion of the transported fluid different from that in the first embodiment. Alternatively, the strain gauge 16 may be disposed in a combination of the non-contact portions shown in the first to sixth embodiments. The strain gauge 16 can be disposed in various locations as long as it can detect the load of the pump device as the amount of strain at the location that is a non-contact portion of the transported fluid, and is not limited to the above-described arrangement.

[0086] REFERENCE SIGNS LIST 10 Drive mechanism 11 Shaft member 11a First member 11b Second member 16 Strain gauge 20 Pump body 21, 25 Housing space 26 Front housing 27 Rear housing 29 Control board 29a Sensor board 30 Pump head 31 Pump chamber 40 Adapter member 50 Diaphragm 54 Retainer member 60 Gasket member 73 Control unit 74 Estimation unit 75 Memory unit 100 Pump device

Claims

1. A pump device comprising: a pump head having an inlet and an outlet for a transported fluid; a diaphragm attached to the pump head and forming a pump chamber connecting the inlet and the outlet; a pump body including a reciprocating member connected to the diaphragm and movable in the reciprocating direction of the diaphragm, a drive mechanism capable of driving the reciprocating member in the reciprocating direction of the diaphragm, and a control unit for controlling the drive mechanism; a sensor unit disposed in a non-contact portion of the transported fluid in the pump device and detecting strain generated in the non-contact portion during operation of the pump device; and an estimation unit for estimating an actual flow rate or pressure of the transported fluid in the pump device based on the amount of strain in the non-contact portion detected by the sensor unit.

2. The pump device according to claim 1, wherein the control unit controls the operation of the drive mechanism based on the actual flow rate estimated by the estimating unit so that the actual flow rate of the transported fluid becomes a preset set flow rate.

3. A pump device as described in claim 2, further comprising a memory unit that stores information indicating an actual flow rate ratio relative to a potential difference of waveform data representing the amount of strain for each stroke number of the reciprocating member that has been created in advance, and the estimation unit estimates the actual flow rate from the potential difference of the waveform data representing the amount of strain by referring to the information indicating the actual flow rate ratio in the memory unit.

4. The pump device according to claim 3, wherein the control unit further comprises a display unit for visually displaying information on the estimated actual flow rate together with a set flow rate.

5. The pump device according to claim 1, wherein the estimation unit estimates that the operating condition of the pump device is abnormal if the output value of the waveform data representing the amount of distortion after a predetermined time has elapsed from the start timing of the suction period of the pump device is greater than a predetermined threshold value, or if the output value of the waveform data representing the amount of distortion after a predetermined time has elapsed from the start timing of the discharge period of the pump device is smaller than a predetermined threshold value.

6. A pump device according to any one of claims 1 to 5, wherein the sensor portion is disposed in the non-contact portion on the outer periphery of the reciprocating member near the connection portion with the diaphragm.

7. The pump device according to any one of claims 1 to 5, wherein a plurality of said sensor parts are arranged in said non-contact portion.

8. A pump device as claimed in any one of claims 1 to 5, wherein the sensor unit is arranged in the non-contact portion of at least one of a reinforcing member attached to the front side of the pump head, a retainer member arranged on the back side of the diaphragm, a bracket member attached to the front side of the drive mechanism, an outer periphery of the reciprocating member located rearward of the front side of the bracket member, and an upper portion of the drive mechanism.

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