JPH1089262A - Pump control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occurrence of trouble, to facilitate maintenance, and further to compact equipment. SOLUTION: A pump control device comprises a main control means 3 electrically connected between a motor M to drive a pump 1 and a power source 2; a current value detecting means 4 to output a detecting signal A by detecting the input current value of the motor M between the main control means 3 and the motor M; and a comparing computing means 5 to receive a detecting signal A from the current value detecting means 4 and compare the detecting signal A with a reference value for computation and output a control operation signal B to a main control means 3. The output Q of the main control means 3 is regulated according to the control operation signal B fed from the comparing computing means 5 to the main control means 3, and the number of revolutions of the motor M is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a device for controlling the discharge pressure of a pump, for example, a pressure switch, a pressure sensor or the like is used to measure and monitor the pressure in a pipe while controlling the rotation speed of a pump driving motor. What was constructed was known.

[0003]

However, as described above, when a pressure switch, a pressure sensor, or the like is used, a liquid containing solids such as slurry, sludge, mortar, concrete, or a fluid that easily solidifies, such as an adhesive, is used. When transporting, there is a problem that friction, breakage, sedimentation, etc. are likely to occur, and even if a diaphragm and special piping for attaching it are used,
Problems such as breakage and sedimentation could not always be solved. Further, there are problems such as trouble of cleaning, adjustment, parts replacement, etc., increase of running cost, and enlargement of devices and facilities.

Therefore, the present invention solves the above-mentioned problems, and has few failures and easy maintenance.
It is another object of the present invention to provide a pump control device capable of making the equipment compact.

[0005]

In order to achieve the above-mentioned object, a pump control device according to the present invention comprises: a main control means electrically connected between a motor for driving a pump and a power supply; Current value detecting means for detecting an input current value of the motor and outputting a detection signal between the control means and the motor, and receiving the detection signal from the current value detecting means to detect the detection signal. And a comparison operation means for comparing and calculating a reference value and outputting a control operation signal to the main control means,
The output of the main control means is increased or decreased in response to a control operation signal sent from the comparison operation means to the main control means to control the rotation speed of the motor.

In accordance with the current value detected by the current value detecting means, the output of the main control means changes in a plurality of steps or in a stepless manner. It is preferable to be configured to change to Further, the motor speed is reduced when the current value detected by the current value detecting means exceeds a predetermined upper limit value, and the motor speed is increased when the current value is smaller than the predetermined lower limit value. Is also desirable.

It is preferable that the motor be rotated reversely when the current value detected by the current value detecting means exceeds a predetermined upper limit, and that the motor be rotated forward after a predetermined time. Further, it is desirable that the motor be stopped when the current value detected by the current value detecting means exceeds the maintenance upper limit value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on the illustrated embodiments.

FIG. 1 shows an embodiment of a pump control device according to the present invention. The pump control device comprises a main control means electrically connected between a motor M for driving a pump 1 and a power supply 2. 3, and a current value detecting means 4 for detecting an input current value of the motor M and outputting a detection signal A between the main control means 3 and the motor M. Also provided is a comparison operation means 5 which receives the detection signal A from the current value detection means 4, compares the detection signal A with a reference value, and outputs a control operation signal B to the main control means 3.

As the motor M, a three-phase induction motor is used. The current value detecting means 4 is composed of a current converter having a rectifier circuit and a current tap setting circuit, and converts the input current of the motor M into a detection signal A which can be compared and calculated by the comparing and calculating means 5 in real time. It is composed of

The comparison operation means 5 has a current setting circuit and a comparison operation circuit, and a reference value is input to the comparison operation circuit in advance or in real time. That is, this pump control device has input setting means 6 for inputting a reference value to the comparison operation means 5 in advance or in real time, and the reference value is input by key input or the like. And the comparison operation means 5
Is configured to output the control operation signal B in real time in conjunction with the reception of the detection signal A.

The main control means 3 includes, for example, an inverter,
It has a sequencer and the like, and is configured so that the output Q (output current or output voltage) increases or decreases in response to the control operation signal B from the comparison operation means 5. The main control means 3 may have a relay or the like depending on the control content.

Thus, the output Q of the main control means 3 changes in a plurality of steps corresponding to the current value detected by the current value detecting means 4, and the rotation speed of the motor M changes in a plurality of steps accordingly. It is constituted so that.

Here, as the discharge pressure of the pump 1 increases, the load on the motor M increases, and accordingly, the input current value of the motor M decreases. Conversely, when the discharge pressure of the pump 1 decreases, the load on the motor M decreases, and accordingly, the input current value of the motor M increases.

Therefore, since the change in the input current value of the motor M is linked to the change in the discharge pressure of the pump 1, monitoring the input current value of the motor M allows the discharge pressure of the pump 1 to be indirectly known. Main control means 3 in conjunction with a change in the current value
, The discharge pressure of the pump 1 can be controlled.

A method of controlling the discharge pressure of the pump 1 will now be described. In response to the current value detected by the current value detecting means 4, the output Q of the main control means 3 is changed in a plurality of stages. Accordingly, the rotation speed of the motor M is changed in a plurality of stages. As a result, the discharge pressure of the pump 1 can be kept almost constant at a desired pressure.

As described above, according to the pump control device, the discharge pressure of the pump can be monitored and controlled without using components such as a pressure switch and a pressure sensor that directly contact the fluid. Therefore, even when transferring a solid-mixed liquid such as slurry, sludge, mortar, and concrete, and a liquid that easily solidifies, such as an adhesive, abrasion, breakage,
Deposition and the like hardly occur. Further, it can be used regardless of the type and properties of the fluid. Further, the equipment can be made compact.

The output Q of the main control means 3 changes steplessly in accordance with the current value detected by the current value detecting means 4, and the rotation speed of the motor M changes steplessly. It is also preferable to configure as follows. By doing so, the discharge pressure of the pump 1 can be maintained with higher accuracy.

When the current value detected by the current value detecting means 4 exceeds a predetermined upper limit value, the rotation speed of the motor M decreases, and when the current value is less than the predetermined lower limit value, the rotation speed of the motor M decreases. It may be configured to rise. If you do that,
The control of the comparison operation means 5 and the main control means 3 can be simplified, and the components can be simplified.

When the current value detected by the current value detection means 4 exceeds a predetermined upper limit, the motor M rotates in the reverse direction,
It is also preferable that the motor M is rotated forward after a predetermined time. By doing so, when the discharge pressure of the pump 1 rises sharply, the pressure can be quickly reduced. Therefore, failures and accidents can be prevented.

Further, the motor M may be configured to stop when the current value detected by the current value detecting means 4 exceeds the maintenance upper limit value. By doing so, the motor M can be protected from overcurrent and the like, and at the same time, occurrence of an accident such as a failure or a fire can be prevented.

[0022]

The present invention has the following remarkable effects by the above-mentioned structure.

According to the pump control device of the first aspect,
The discharge pressure of the pump can be monitored and controlled without using components that directly touch the fluid, such as a pressure switch and a pressure sensor. Therefore, abrasion, breakage, sedimentation, and the like are less likely to occur even when transferring a solid-mixed liquid such as slurry, sludge, mortar, and concrete, or a liquid that easily solidifies, such as an adhesive. Further, it can be used regardless of the type and properties of the fluid. Further, the equipment can be made compact. Further, it can contribute to a reduction in running costs.

According to the pump control device of the second aspect,
The same effect as that of the first aspect is obtained, and the discharge pressure of the pump 1 can be maintained at a desired pressure with high accuracy.

According to the pump control device of the third aspect,
The same effects as those of the first aspect are obtained, and the control of the comparison operation means 5 and the main control means 3 can be simplified, and the components can be simplified.

According to the pump control device of the fourth aspect,
The same effects as those of the first, second, and third aspects can be obtained, and when the discharge pressure of the pump 1 rises rapidly, the pressure can be rapidly reduced. Therefore, failures and accidents can be prevented.

According to the pump control device of the fifth aspect,
The same effect as that of the first, second, third, or fourth aspect is obtained, and the motor M can be protected from overcurrent or the like. In addition, it is possible to prevent occurrence of accidents such as breakdowns and fires.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 pump 2 power supply 3 main control means 4 current value detection means 5 comparison calculation means A detection signal B control operation signal M motor Q output

Claims (5)

[Claims] 1. A motor M for driving a pump 1 and a power supply 2.
Main control means 3 electrically connected between the main control means 3 and a current value detecting means for detecting an input current value of the motor M and outputting a detection signal A between the main control means 3 and the motor M Means 4 for receiving a detection signal A from the current value detection means 4, comparing the detection signal A with a reference value, and outputting a control operation signal B to the main control means 3. Means 5 for controlling the number of revolutions of the motor M by increasing or decreasing the output Q of the main control means 3 in response to the control operation signal B sent from the comparison operation means 5 to the main control means 3 A pump control device characterized in that: 2. The output Q of the main control means 3 changes in a plurality of steps or steplessly in accordance with the current value detected by the current value detecting means 4, and accordingly, the rotation speed of the motor M changes in a plurality of steps. The pump control device according to claim 1, wherein the pump control device is configured to change continuously. 3. When the current value detected by the current value detection means 4 exceeds a predetermined upper limit, the rotation speed of the motor M decreases, and when the current value falls below the predetermined lower limit, the rotation speed of the motor M decreases. The pump control device according to claim 1, wherein the pump control device is configured to rise. 4. The motor M is configured to rotate in a reverse direction when the current value detected by the current value detecting means 4 exceeds a predetermined upper limit value, and to rotate forward after a predetermined time. The pump control device according to claim 1, 2 or 3. 5. The pump according to claim 1, wherein the motor M is stopped when the current value detected by the current value detection means 4 exceeds a maintenance upper limit value. Control device.