JP5017335B2 - Abnormality detection device for positive displacement pump - Google Patents

Description

  The present invention detects a pulsation of a fluid discharged from a positive displacement pump (hereinafter sometimes simply referred to as a pump) to a pipe and, for example, a gas lock caused by gas volatilization that occurs when a high-concentration chemical is used, The present invention also relates to an abnormality detection device for a positive displacement pump that detects an abnormality in a closed state of a discharge port of the pump.

  As a conventional positive displacement pump abnormality detection device, for example, a pump body in which a valve chamber is formed, a plunger reciprocatingly provided in the pump body, a solenoid for reciprocatingly driving the plunger, a plunger And a ball valve body that discharges fluid in the valve chamber to the outlet passage, an outlet passage member that is connected to the pump body and that communicates with the valve chamber, and an outlet passage member formed in the outlet passage member. A device provided with an externally fitted piezoelectric element is known.

  According to the apparatus, the fluid is discharged and sucked by moving the plunger and the ball valve body in and out in synchronization with the on / off of the solenoid. At this time, the piezoelectric element compares the waveform at the normal time with the waveform when the oil outage and the clogging of the outlet passage are abnormal, and detects the oil outage and the clogging of the outlet side.

  Further, as an abnormality detecting device for a positive displacement pump according to another conventional example, a diaphragm attached to a tip end of a drive shaft, a pump chamber formed by the diaphragm and a pump body, and below and above the pump chamber A suction passage and a discharge passage, a discharge passage and a fluid pressure detection passage branched from the discharge passage, a check valve connected to the discharge passage, and a pressure sensor provided in the fluid pressure detection passage. Things are known. The pressure sensor includes a diaphragm that responds to pressure, and a plurality of piezoresistors and electronic circuits that are formed on the upper surface of the diaphragm and detect the distortion of the diaphragm. Further, since the diaphragm is disposed so as to face the hydraulic pressure detection passage, the diaphragm is surface-treated in order to prevent corrosion due to liquid contact.

  According to the apparatus, the start timing of the discharge cycle is detected based on the output detected by the pressure sensor, and a predetermined pulse corresponding to the pulsation of the pump is output. When the air is mixed into the pump, the pressure in the fluid pressure detection passage rapidly decreases, the pulse signal output is stopped, and an alarm is output.

JP 2002-48073 A Japanese Patent No. 3334402

  However, although the former positive displacement pump abnormality detection device can be applied to a solenoid pump, the description applicable to a motor pump is not disclosed or suggested, and is considered to be less versatile.

  In addition, the latter positive displacement pump anomaly detection device uses a pressure sensor, so it is necessary to perform surface treatment on the liquid contact surface of the diaphragm. Is done.

  The present invention has been made in view of the above circumstances, and can be applied to any pumps that use solenoids and motors as drive sources, and can be easily and inexpensively manufactured. It is an object to provide a detection device.

In order to solve the above-described problem, an abnormality detection device for a positive displacement pump according to the present invention is an abnormality detection device for a positive displacement pump that detects an abnormality of the positive displacement pump 2 using either a solenoid or a motor as a drive source. Signal processing means for processing a detection signal of the sensor 10 when the solenoid 10 is used as a drive source, and includes a sensor 10 composed of a piezoelectric element that is fitted on a pipe 3 connected to the discharge port of the pump 2 when, a second signal processing means for processing a detection signal of the sensor 10 in the case where the motor as a driving source is Ru with a composed signal processing section 15 so as to be switched in accordance with the respective drive sources.

  In this case, since the sensor 10 composed of a piezoelectric element is externally fitted to the pipe 3 connected to the discharge port of the positive displacement pump 2, the pulsation of the fluid can be achieved without bringing the detection surface of the sensor 10 into contact with liquid. Can be detected through the pipe 3. For this reason, it is not necessary to perform the surface treatment on the detection surface of the sensor 10 as in the prior art, and accordingly, the machining process is unnecessary, and the cost can be reduced.

  In this case, even if it is the positive displacement pump 2 which uses either a solenoid or a motor as a drive source, the signal processing according to a drive source will be performed, and versatility will become high.

  According to the present invention, a sensor constituted by a piezoelectric element is externally fitted to the pipe connected to the discharge port of the positive displacement pump, and the pulsation of the fluid transmitted to the pipe is detected. There is an effect that can be manufactured.

The schematic block diagram of the fluid conveyance apparatus provided with the abnormality detection apparatus of the positive displacement pump which concerns on one Embodiment of this invention. The disassembled perspective view which shows the fixed adapter by which the piezoelectric element was equipped internally. FIG. 3 is a perspective view of the fixing member of FIG. The plane sectional view in the state where the bolt screwed to the fixing member. (A) Synchronizes the solenoid ON signal and the sensor detection signal to the ON signal, and A / D converts the detection signal within the first and second setting levels to form a normal waveform. The figure which shows the state to do. FIG. 6B is a diagram showing a state in which a closed waveform is formed by A / D converting a solenoid ON signal and a detection signal exceeding the second set level by synchronizing the detection signal of the sensor with the ON signal. (C) shows a state in which a gas lock waveform is formed by A / D converting a solenoid ON signal and a detection signal lower than the first set level by synchronizing the sensor detection signal with the ON signal. Figure.

  Hereinafter, an embodiment of an abnormality detecting device for a positive displacement pump according to the present invention will be described with reference to FIGS.

  An abnormality detection device for a positive displacement pump according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4 including a fluid conveyance device that conveys a fluid by the positive displacement pump. As a fluid, for example, a tank 1 in which a high concentration chemical solution is stored, a positive displacement pump 2 that sucks and discharges the fluid in the tank 1 and conveys the fluid to a supply pipe 4 through a connection pipe 3 described later, A connection pipe 3 connected to the discharge port of the positive displacement pump 2, a supply pipe 4 connected to the connection pipe 3, a sensor 10 fitted on the connection pipe 3 by a fixed adapter 5, and a positive displacement pump 2 The signal processing unit 15 that processes the detection signal of the sensor 10 according to the driving source (solenoid and motor), and the signal processing of the detection signal of the sensor 10 according to the driving source provided in the signal processing unit 15 It comprises a changeover switch (not shown) for switching a plurality of signal processing means to perform.

  Although not shown, the positive displacement pump 2 uses a solenoid as a drive source, and when the solenoid is turned off and on, the plunger reciprocates to suck and discharge the fluid and transport it to the supply pipe 4 on the downstream side. It is configured.

  As shown in FIGS. 2 to 4, the fixing adapter 5 includes a prismatic fixing member 6 and a bolt B that is screwed into the fixing member 6. The fixing member 6 is formed with a screw hole 7 of the bolt B from the central part of one side surface to the central part, and is opposed to the central part of the other surface adjacent to the one surface so as to be orthogonal to the screw hole 7. An insertion hole 8 of the connection pipe 3 is formed over the center of the surface. Further, as shown in FIG. 4, a recess 8 a for setting the sensor 10 is formed on the inner surface of the insertion hole 8 facing the screw hole 7. When the sensor 10 is set in the recess 8a, the detection surface 10a of the sensor 10 protrudes from the inner surface of the insertion hole 8, that is, the detection surface 10a of the sensor 10 contacts the outer surface of the connection pipe 3. It is in.

  As shown in FIGS. 2 to 4, the sensor 10 includes a disk-shaped piezoelectric element (piezoelectric element) having a diameter of 5 mm and a thickness of 1.5 mm. And the detection signal which detected the pulsation of the fluid which flows into the connection piping 3 performs required signal processing by the signal processing part 15 mentioned later. That is, the detection signal of the sensor 10 is synchronized with the solenoid ON signal and compared with two threshold values (set levels) set to a predetermined level to determine whether the pump 2 is normal or abnormal. This signal processing will be described in detail later.

The signal processing unit 15, a first signal processing means for processing a detection signal of the sensor 10 the solenoid as a drive source, a second signal processing means for processing a detection signal of the sensor 10 by using a motor as a drive source, a solenoid or motor And a drive source switching mode for switching each signal processing means according to the drive source.

  The first signal processing means synchronizes the solenoid ON signal and the detection signal of the sensor 10, and compares the synchronized detection signal with the first and second set levels set to a predetermined level. As shown to (a), when the level of a detection signal (about 2V) exists in the range of a 1st and 2nd setting level, it makes A / D conversion, ie, a pulse waveform, using the determined detection signal as a normal waveform. The pulse waveform is constantly output to the outside. Further, as shown in FIG. 5B, when the level of the detection signal exceeds the second set level (about 5V), the determined detection signal is converted into a pulse waveform as a closed waveform, and the pulse waveform is continuous. If it is detected (for example, 1 to 5 times), a blockage alarm is issued. As shown in FIG. 5C, when the level of the detection signal is less than the first set level (about 0 to 1 V), the determined detection signal is converted into a pulse waveform as a gas lock waveform, and the pulse If the waveform is detected a predetermined number of times, a gas lock alarm is issued. Further, when the blockage and gas lock alarms are issued and the normal waveforms are continuously detected, each alarm is stopped.

  If the normal waveform shown in FIG. 5 (a) is not input within a predetermined time (for example, 1 to 60 seconds), that is, within a time exceeding at least one cycle of the pump operation cycle, the second signal processing means, It judges that it is in a gas lock state, and issues a gas lock alarm. When the block waveform shown in FIG. 5B is output continuously (for example, 1 to 5 times) within the predetermined time, it is determined that the block is in the block state and a block alarm is issued. Further, when the gas lock waveform shown in FIG. 5C is continuously output within the predetermined time, it is determined that the gas lock state is set, and a gas lock alarm is issued. If none of the normal waveform, blockage waveform, and gas lock waveform is output during the predetermined time, a gas lock alarm is issued.

  In order to install the sensor 10 in the connection pipe 3, the sensor 10 is set in advance in the recess 8 a of the insertion hole 8 of the fixing member 6, and the bolt B is screwed into the screw hole 7 of the fixing member 6. Then, the connection pipe 3 is inserted into the insertion hole 8 of the fixing member 6. Thereafter, the fastening member 6 is fixed to the connection pipe 3 by finally tightening the bolt B, the detection surface 10a of the sensor 10 is pressed against the outer surface of the connection pipe 3, and the pulsation of the fluid flowing through the connection pipe 3 is detected by the sensor 10. Detected by.

  Then, the drive source switching mode of the signal processing unit 15 is switched to either the solenoid or the motor by the changeover switch so that the detection signal of the sensor 10 can be processed according to the drive source of the positive displacement pump 2. For example, when the drive source of the positive displacement pump 2 is a solenoid, the changeover switch is switched to “solenoid”. Thereafter, when the positive displacement pump 2 is driven, the fluid is conveyed to the supply pipe 4 through the connection pipe 3, and the sensor 10 detects pulsation through the connection pipe 3. Specifically, in the first signal processing means of the signal processing unit 15 described above, when an ON signal is input to the solenoid, as shown in FIGS. The detection signal of the sensor 10 is output, and whether the detection signal is within the range of the first and second setting levels or exceeds the second setting level set higher, the first set to be lower It is determined whether or not the pump 2 is lower than one set level, and whether the pump 2 is normal or abnormal is determined.

  When the drive source of the positive displacement pump 2 is a motor, when the changeover switch is switched to “motor” and the positive displacement pump 2 is driven, within a predetermined time from the rise of the pump ON signal, that is, at the minimum of the operation cycle of the pump. Within the time exceeding one cycle, in the second signal processing means of the signal processing unit 15, the normal waveform shown in FIG. 5 (a), the closed waveform shown in FIG. 5 (b), and the gas shown in FIG. 5 (c). Whether the pump 2 is normal or not is determined based on whether or not a lock waveform is output.

  In the case of the above-described embodiment, the plurality of signal processing means in the signal processing unit 15 are switched by the changeover switch (manual) according to the drive source, but the presence or absence of the synchronization signal synchronized with the suction / discharge of the positive displacement pump May be detected and switched automatically.

  In the case of the above embodiment, the abnormality of the pump is detected by counting the normal waveform shown in FIG. 5A, but the flow rate of the fluid to be conveyed and the operation time of the pump are measured. Therefore, it can also be applied to pump flowmeters and life management devices.

  In the case of the above embodiment, the prismatic fixing member 6 is used. However, the fixing member may be divided into two, and the piping 3 may be sandwiched by the divided fixing member. Also good.

  DESCRIPTION OF SYMBOLS 1 ... Tank, 2 ... Positive displacement pump, 3 ... Connection piping, 4 ... Supply piping, 5 ... Fixed adapter, 6 ... Fixing member, 7 ... Screw hole, 8 ... Insertion hole, 8a ... Recessed part, 10 ... Sensor, 10a ... Detection surface of sensor, 15 ... signal processing unit, B ... bolt.

Claims (1)

In an abnormality detection device for a positive displacement pump that detects an abnormality of a positive displacement pump (2) using either a solenoid or a motor as a drive source,
A sensor (10) composed of a piezoelectric element, fitted on a pipe (3) connected to the discharge port of the positive displacement pump (2) ;
First signal processing means for processing the detection signal of the sensor (10) when the solenoid is used as the drive source, and second signal processing means for processing the detection signal of the sensor (10) when the motor is used as the drive source An apparatus for detecting an abnormality of a positive displacement pump , comprising a signal processing unit (15) configured to be switchable according to each driving source .

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