JPH0749083A - Operation control method for pressure tank type automatic water feeder - Google Patents

Abstract

PURPOSE:To stop operation of a pump at a predetermined discharge quantity irrespective of pressure fluctuation even if a pressure of an inlet of the pump is fluctuated. CONSTITUTION:A differential pressure gauge 8 measures a differential pressure between an inlet 1B and outlet 1A of a pump 1. A controller 7 receives the measured differential pressure as the present whole head. When the whole head becomes equal to a whole head DELTAh previously input into the controller 7, i.e., a whole head DELTAh corresponding to an operation stopping discharge quantity Q1 of a whole head and a discharge quantity characteristic of the pump 1, the controller 7 outputs an operation stopping signal into a motor 1C of the pump 1, thus stopping operation of the pump 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control method for a pressure tank type automatic water supply apparatus applied to water supply equipment in a wide variety of fields.

[0002]

2. Description of the Related Art A conventional pressure tank type automatic water supply system is constructed, for example, as shown in FIG. That is, the pressure tank 3 is provided in the middle of the water supply pipe 2 connected to the discharge port 1A of the pump 1 so that the tip of the suction pipe 4 connected to the suction port 1B of the pump 1 faces the water tank 5 and When the pressure in 3 decreases and reaches the starting pressure P2 of the pump 1, the pressure switch 6 detects this pressure P2 and outputs a starting signal to the prime mover 1C of the pump 1 to start the pump 1.

On the other hand, if the usage on the demand side downstream of the water supply pipe 2 is smaller than the discharge obtained by the operation of the pump 1, the pressure rises due to the rise of the water level in the pressure tank 3, and the operation stop pressure of the pump 1 At P1, this pressure P
1 is detected, an operation stop signal is output to the prime mover 1C of the pump 1, and the pump 1 is stopped.

By the way, in order to reduce the frequency of operation / stop of the pump 1, when the consumption on the demand side downstream of the water supply pipe 2 becomes small and the discharge of the pump 1 decreases to a predetermined value which is as small as possible. It is desirable to do in. However, in the operation control method in which the operation of the pump 1 is stopped based on the operation stop pressure P1 in the pressure tank 3 as in the conventional case, the operation of the pump 1 is not always stopped when the discharge amount drops to a predetermined value. A state in which the pump 1 is stopped before the discharge amount drops to a predetermined value, that is, the usage amount on the demand side downstream of the water supply pipe 2 is large and the discharge amount is large. Easy to invite. Therefore, the pressure in the pressure tank 3 is reduced to the starting pressure P2 in a short time, and the pump 1 is restarted, so that the frequency of operation / stop of the pump 1 is increased and the pump 1 is a cause of failure. become.

That is, in the conventional operation control method of the pressure tank type automatic water supply apparatus, for example, the water level of the water tank 5 is high,
Even when the discharge amount is large because the pressure of the suction port 1B is high, or when the water level is low in the water tank 5 and the discharge amount is small because the pressure of the suction port 1B is low, the pressure in the pressure tank 3 is the operation stop pressure pressure. Since the operation of the pump 1 is stopped when it rises to P1, the operation of the pump 1 is often stopped despite the large discharge amount. Therefore, even if the pressure at the suction port 1B fluctuates, there is a demand for the development of an operation control method capable of stopping the operation of the pump 1 with a predetermined discharge amount as small as possible regardless of this pressure fluctuation.

[0006]

The problem to be solved is that the operation of the pump is stopped when the pressure in the pressure tank rises to the operation stop pressure. The discharge rate fluctuates when the pump is stopped. Therefore, the pump operation is likely to be stopped despite the large discharge amount, so that the pressure in the pressure tank drops to the starting pressure in a short time, and the pump is restarted. , Pump operation
This is one of the causes of frequent pump outages and pump failure.

[0007]

According to the present invention, in a pressure tank type automatic water supply device in which a pressure tank is provided in the middle of a water supply pipe connected to a discharge port of a pump, the operation stop discharge amount of the pump is determined, The total head corresponding to the above-mentioned operation stop discharge amount of the total pump head / discharge amount characteristic is input to the control means in advance, and the differential pressure between the suction port and the discharge port of the pump is measured by a differential pressure gauge, and the measured difference is measured. The pressure is input to the control means as the current total head, and when the input current total head becomes equal to the total head previously input to the control means,
The control means outputs an operation stop signal to the prime mover of the pump to stop the operation of the pump, and the object of stopping the operation of the pump at a predetermined discharge amount is achieved regardless of the pressure fluctuation of the suction port.

[0008]

According to the present invention, the differential pressure between the suction port and the discharge port of the pump measured by the differential pressure gauge is input to the control means as the current total head. In the control means, the current total head input and the total head corresponding to the operation stop discharge amount that has been input in advance are compared, and the input current total head becomes the total head corresponding to the operation stop discharge amount. When they are equal, an operation stop signal is output to the prime mover of the pump to stop the operation of the pump. That is, the discharge amount at the time of outputting the operation stop signal from the control means to the prime mover of the pump is unified to the operation stop discharge amount of the pump.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing the configuration of an embodiment of the present invention. It should be noted that the same or corresponding parts as those in the conventional example of FIG. In FIG. 1, the pump 1
Pressure tank 3 in the middle of the water supply pipe 2 connected to the discharge port 1A of
The end of the suction pipe 4 connected to the suction port 1B of the pump 1 is made to face the inside of the water tank 5, and when the pressure in the pressure tank 3 decreases to the starting pressure P2 of the pump 1, this pressure P2 Is detected by the pressure switch 6, and this detection signal is input to the control means 7, which outputs a start signal to the prime mover 1C of the pump 1 to start the pump 1.

On the other hand, the suction port 1B and the discharge port 1A of the pump 1
The differential pressure is measured by the differential pressure gauge 8 and the measured differential pressure ΔP is input to the control means 7 as the current total lift. Further, in the total lift / discharge amount characteristic of the pump shown in FIG. 2, the control unit 7 is previously input with the total lift Δh corresponding to the operation stop discharge amount Q1. Then, from the control means 7 to the pump 1
The pump 1 is stopped by outputting a stop signal to the prime mover 1C.

With such a configuration, when the pump 1 is in operation, the differential pressure gauge 8 measures the differential pressure ΔP between the suction port 1B and the discharge port 1A of the pump 1. The differential pressure ΔP measured by the differential pressure gauge 8 is input to the control means 7 as the current total head. Since the total head Δh corresponding to the operation stop discharge amount Q1 is input in advance to the control means 7, the control means 7 compares the current total head and the total head Δh corresponding to the operation stop discharge amount Q1. To be done. Since the usage amount on the demand side at this point is large, when the discharge amount obtained by the operation of the pump 1 is larger than the operation stop discharge amount Q1, the operation of the pump 1 is continued.

On the other hand, when the demand side usage amount decreases and the discharge amount obtained by the operation of the pump 1 becomes equal to the operation stop discharge amount Q1, that is, the current total head corresponds to the operation stop discharge amount Q1. When it becomes equal to the total lift Δh, the control means 7 outputs a stop signal to the prime mover 1C of the pump 1 to stop the pump 1.

As described above, since the pump 1 is stopped when the current total head becomes equal to the total head Δ corresponding to the operation stop discharge amount Q1, the pressure at the suction port 1B fluctuates. Also, the operation of the pump 1 can be stopped at the determined predetermined discharge amount Q1 regardless of this pressure fluctuation. Therefore, if the operation stop discharge amount Q1 is set to a value as small as possible, the operation of the pump 1 will not be stopped even though the use amount on the demand side downstream of the water supply pipe 2 is large and the discharge amount is large. Absent. Therefore, the pressure in the pressure tank 3 is reduced to the starting pressure P2 in a short time, and the inconvenience that the pump 1 is restarted does not occur, and the frequency of operating and stopping the pump 1 is reduced, and the pump 1 fails. Can be avoided.

[0014]

As described above, according to the present invention,
The differential pressure between the suction port and the discharge port of the pump measured by the differential pressure gauge is input to the control means as the current total head, and here, the total head corresponding to the operation stop discharge amount that has been input in advance is compared and input. When the current total pump head becomes equal to the total pump head corresponding to the operation stop discharge amount, an operation stop signal is output to the prime mover of the pump to stop the pump operation. The discharge amount at the time of outputting the operation stop signal to the prime mover can be unified to the operation stop discharge amount of the pump regardless of the pressure fluctuation of the suction port. Therefore, the pressure in the pressure tank drops to the starting pressure in a short time, and the inconvenience of restarting the pump does not occur,
It becomes possible to reduce the frequency of operation / stop of the pump and avoid the failure of the pump.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a total head / discharge amount characteristic of a pump.

FIG. 3 is a system diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1 Pump 1A Pump discharge port 1B Pump suction port 1C Pump prime mover 2 Water supply pipe 3 Pressure tank 7 Control means 8 Differential pressure gauge Q1 Pump operation stop discharge amount Δh Total pump head corresponding to operation stop discharge amount

Claims (1)

[Claims] 1. In a pressure tank type automatic water supply device in which a pressure tank is provided in the middle of a water supply pipe connected to a discharge port of a pump, the operation stop discharge amount of the pump is determined, and the total head / discharge amount characteristics of the pump are determined. The total head corresponding to the above operation stop discharge amount is input to the control means in advance, the differential pressure between the suction port and the discharge port of the pump is measured by a differential pressure gauge, and the measured differential pressure is controlled as the current total head. Input to the means, and when the current total head input is equal to the total head previously input to the control means, the control means outputs an operation stop signal to the prime mover of the pump to stop the operation of the pump. A method for controlling the operation of a pressure tank type automatic water supply device, which comprises: