JPS586007Y2 - pump pressure control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a pump pressure control device that generates a speed command, changes the pump speed, and controls the water supply pressure.

Figure 1 shows the configuration of a conventional water pump device.
1 is a power supply device, 2 is a motor that connects and drives the pump 3,
4 is a pressure detector for detecting the water supply pressure of the discharge side piping of the pump 3, 5 is a pressure setting device, and 6 is a comparison calculator.

In FIG. 1, a power supply device 1 has a speed command 101 and a motor 2.
A speed feedback signal 102 is input, and, for example, the electric power applied to the motor 2 is changed so as to change the rotation speed of the motor 2 according to this speed command 101.

The pump 3 is powered by such a power supply 1 and motor 2.
performs water supply operation by changing its rotational speed.

The pressure setting device 5 receives a set pressure signal 1 which is set so that the water supply pressure of a general household at the demand end has a predetermined value, for example.
03, and the comparator 6 outputs the pressure setting signal 103.
The speed command 101 is generated by inputting the pressure feedback signal 104 from the pressure detector 4 and comparing the pressure feedback signal 104 with the pressure setting signal 103.

Therefore, the pressure control section consisting of the pressure detector 4, pressure setting device 5, and comparator 6 uses pressure feedback signals 1
04 and generates a speed command 101 to stably control the water supply pressure based on the pressure setting signal 103, and changes the rotation speed of the pump 3 according to the speed command 101.
This is to control the water supply pressure from the

The water supply pump device configured in this manner is used to supply water for daily use, but it is known that if the water supply pressure changes abnormally, various problems will occur and cause great damage.

However, in such a water supply pump device, if the pressure control section fails or becomes disabled due to disconnection of the connecting wire, the speed command 101 usually generates a maximum output value or a minimum output value.

Therefore, the pump 3 suddenly changes to either the maximum speed or the minimum speed and is fixed, making it impossible to control the water supply pressure in response to changes in flow rate.

That is, when the pressure control section is in a disabled state, for example, if the pressure detector 4 fails, the output of the pressure feedback signal 104 is usually fixed at either the minimum or maximum value, and the speed command 101 output from the comparator 6 is set to the maximum value or the minimum value. occurs, and the pump 3 is biased toward either the maximum speed or the minimum speed.

In this state, if the pump 3 is fixed at the maximum speed, the water supply pressure will be increased as the flow rate decreases, and if the pump 3 is fixed at the minimum speed, the water supply pressure will be decreased more as the flow rate increases. .

Furthermore, when the above-mentioned uncontrollable state of water supply pressure occurs, the control mode of the device is switched to manual operation, and then maintenance personnel appropriately manipulate the water supply pressure.

As described above, water supply methods using pressure control are commonly used in conventional water supply pump devices, but these devices do not have sufficient effective measures to maintain water supply pressure when the pressure control section is disabled. There was a problem in that the equipment lacked reliability as a water supply facility for domestic use.

The present invention was developed by focusing on the above-mentioned points, and it is possible to appropriately change the water supply pressure even when the pressure control part is disabled, without causing any problems in water supply through normal pressure control of the water supply pump device. To provide a pressure control device that can

The present invention will be explained below with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same components.

In FIG. 2, reference numeral 7 denotes a command correction circuit which obtains the speed command 101 from the comparator 6 and generates a corrected speed command 101';
is a pressure switch circuit that sends correction commands 105 and 105' to the command correction circuit 7.

That is, the device shown in FIG. 2 is the same as the device shown in FIG. 1 in that a speed command 101 is generated from a comparator 6 that receives a pressure setting signal 103 and a pressure feedback signal 104 as input, but
The configuration is different from the device shown in FIG. 1 in that a command correction circuit 7 and a pressure switch circuit 8 are provided, and instead of the speed command 101, a modified speed command 101' is generated and inputted to the power supply device 1.

This command correction circuit 7 includes an upper limit value correction section 7a and a lower limit value correction section 7b, and the pressure switch circuit 8 is a known pressure switch 8 that is operated by the water supply pressure supplied from the pump 3.
It consists of a, 8b.

Further, between the command correction circuit 7 and the pressure switch circuit 8, a correction command 105 from the pressure switch 8a and a correction command 105' from the pressure switch 8b are both input to the upper limit value correction section 7a and the lower limit value correction section 7b.

Here, the pressure switch circuit 8 is operated to detect the water supply pressure at a level within a predetermined range with respect to the value set by the pressure setting signal 103, and the water supply pressure exceeds the upper limit pressure value of this predetermined range. When the pressure increases, the pressure switch 8a is activated, and when the water supply pressure decreases below the lower limit pressure value of a predetermined range, the pressure switch 8b is activated to detect the pressure increase and pressure decrease states, and make corrections at the time of this detection. Directive 1
05 or correction command 105'.

Further, the command correction circuit 7 is configured such that when the correction commands ios and ios' are sent out, the upper limit value correction section 7a
The lower limit value corrector 7b acts to increase the minimum output value of the speed command 101 to correct and generate the speed command value.

In other words, when the correction command 105 is sent, the correction speed command 1
The value of 01' is corrected to decrease, and the correction command 105' is
When the signal is sent out, the signal is generated with the same modification so that it increases.

In this speed command value correction control, more stable control can be achieved by having a large integral element.

The speed command correction part monitors the water supply pressure at the upper and lower limit pressure values that have a predetermined range with respect to the set pressure value, detects the state of pressure increase or pressure drop in the water supply pressure, and calculates the speed command 101. is the maximum output value as explained in Figure 1,
Even if the output value is fixed at one of the minimum output values, this human power is obtained to reduce the speed command value when the pressure is rising, and increase the speed command value when the pressure is falling, so that the water supply pressure is appropriate.

Note that the level amount in a predetermined width for the set pressure value can be easily selected from the allowable level of water supply pressure, pump characteristics, flow rate change pattern, etc., and is sufficient to back up water supply operation with normal pressure control. The water supply pressure can be easily adjusted as long as it is set as wide as possible.

In addition, when the pressure switch 8a8b is activated, the correction commands 115, 115 are sent after confirming the detection using the timer characteristics.
By sending out ', it is possible to effectively correct the speed command value.

Furthermore, in the command correction circuit 7, by inputting the speed command 101 and generating a signal to limit the upper and lower limit values of the corrected speed command 101', it is easy to select the maximum and minimum pump speeds by adjusting the limit values. Therefore, the correction command 105. is executed without causing any trouble to normal pressure control.
105' allows corrective control of the water supply pressure.

Furthermore, even if the correction levels of the upper limit value correction section 7a and the lower limit value correction section 7b are kept constant and the sampling operation is performed while the correction commands 105, 105' are being sent out, highly stable correction control can be achieved. It is possible.

For example, in a device where the pump speed is in the range of about 20%, according to an actual machine test with a correction level amount of 20% and a period of 20 seconds, pressure switch 8a
.

8b was deactivated, and excellent results were obtained in that the correction operation was performed only about 2 to 3 times in 5 minutes even during times when the flow rate was changing rapidly.

By making it possible to adjust each of these correction levels, it becomes possible to perform control with good followability in response to the speed increase or deceleration characteristics of the pump speed.

As described above, according to the present invention, it is possible to provide a pressure control device that detects a state of pressure increase or pressure decrease even when the pressure control section is disabled and corrects the water supply pressure appropriately, and improves pressure control by the water supply pump device. It has an excellent practical advantage of further improving the reliability of water supply operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional water pump device;
FIG. 2 is a block diagram showing one embodiment of the present invention. 1...Power supply device. 2...Motor, 3...Pump, 101
...Speed command of comparator 6, 101'...
... Corrected speed command of command correction circuit 7, 103...
...Pressure setting signal, 104...Pressure feedback signal,
105, 105'...Correction command for pressure switch circuit 8.

Claims (1)

[Scope of utility model registration request] In a pump pressure control device that obtains a pressure setting signal and a pressure feedback signal to generate a speed command, and controls the water supply pressure by changing the pump speed according to the speed command, the speed command is input and the value of the speed command is a command correction circuit that generates a corrected speed command by decreasing or increasing the value of the pressure setting signal, and a pressure switch circuit that detects the water supply pressure by having a level within a predetermined range in the value of the pressure setting signal, A pump pressure control device characterized in that the water supply pressure can be changed by decreasing the corrected speed command when an upper limit value of the level is detected and increasing the corrected speed command when a lower limit value of a predetermined width is detected.