JPS5885382A - Method of driving variable speed pump - Google Patents

Abstract

PURPOSE:To reduce the number of times of starting/stopping a pump by increasing the speed of a motor until the pressure within a pressure tank is elevated up to a certain pressure that is higher than the prescribed feed water pressure after the lapse of a certain specified time from the time when a flow detector detects that the flow rate is less than the prescribed minimum flow rate. CONSTITUTION:When a flow detector 7 attached to a feed water pipe 6 is operated due to the flow rate less than the prescribed minimum flow rate, the signal is sent to a control unit 12 which, if the signal stands on over a certain prescribed time, sends electric power to a variable speed motor 4 in order to increase the discharge rate of a feed water pump 5. Because of less water consumption in comparison with the quantity of the water conveyed through a feed water pipe 6, the rest of water flows into a pressure tank 9, which is branched from the pipe 6, elevating the water level in the tank 9. When a pressure detector 11, which carries operation even with prescribed feed water pressure, detects the prescribed upper limit pressure, it sends a signal to the unit 12 to stop the power supply to the motor 4. While the pump 5 stops its operation, the water to be used is supplied from the tank 9. And when the water level in the tank 9 is lowered, or the pressure within the tank is lowered, the motor 4 restarts its operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the operating method of a variable binary water feed pump that stops the amount of water used at an extremely low level. If the amount of water decreases, operating power is wasted, so a pressure tank is installed in the waterway and a 74-switch is installed.If the extremely small amount of water detected by the 70-switch continues for a certain period of time, the water pump is stopped, and during that time the pressure tank is turned off. The water supply is supplemented with the stored water, and in that case, when the pump is stopped, the water supply pressure becomes the specified positive pressure, and the pressure at the liquid junction stored in the pressure tank also becomes that value. On the other hand, the minimum pressure required for a water supply piping system is slightly lower than the normal water supply pressure, and if you try to start the pump at a pressure lower than that pressure, there will be places where no water will come out, and Depending on the actual lift, there may be cases where the pressure inside the piping does not drop and startup is not possible.

Therefore, the pressure range in which water can be supplied by a pressure tank is very limited, and the effective volume cannot be large enough, and the pump will start up as soon as that amount of water is used. Furthermore, if the startup frequency is to be reduced, a large pressure tank is required.In other words, it has the following disadvantages.

(1) Since the pressure range for stopping and starting the pump cannot be wide enough, the pump starts up first in a small-capacity pressure tank, which increases the frequency of starting up and poses a problem in the durability of the pump. In addition, the operating time becomes longer and energy cannot be saved.

-(2) Attempting to solve (1) requires a large-capacity pressure tank, which becomes expensive.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the drawbacks of the conventional variable speed pump operating method described above, and to provide a variable speed pump operating method that allows a large effective volume of the pressure tank and a high stopping pressure of the pump. It is something.

Hereinafter, the operating method of the present invention will be explained using the drawings. 7th
The figure shows an example of an i-tube system for carrying out the present invention. Water is pumped up by a water supply pump 3 driven by a variable speed motor through a water suction pipe J from a 7-tooth valve 1 in a water receiving tank l, and is supplied through a water supply pipe 6. Although not shown, the water pipes 6 usually branch toward their ends and each end at a water tap. First, a flow switch 7 is inserted into the base of the water supply pipe, and the water in the water supply pipe 6 is stored in a pressure cutter/kude from the branch pipe S4, and a pressure detector L/ is installed between the branch pipes. is installed so that the pressure in the pressure tank, that is, the pressure in the water pipe on the pump side, can be detected.

The flow switch operates when the discharge amount of the water supply pump 5 to the water pipe 6 becomes less than the set water amount, and the signal is sent to a control device equipped with, for example, a microcomputer, an amplifier circuit, and an output circuit. . The signal from the pressure detector ii is sent to the control device /J, and the control device I is wired to send power to the variable speed motor.

When the amount of water used at the water pipe end exceeds the set water amount of the 74 switch, the water supply pump 5 is continuously driven by the variable pump, and when the amount of water used increases and the water pressure in the water pipe 6 decreases, the pressure decreases. The detector // detects the drop in water supply pressure and operates, and the signal is sent to the controller, which sends power to increase the speed of the variable speed motor. rotates at an increased speed, and similarly, the water supply pump 3 is increased in speed and becomes a water supply pump! The discharge amount increases.

The water supply pressure increases and the signal of the pressure detector // is restored to the specified water supply pressure, and the signal is sent to the control device l-, which rotates the variable speed motor at the appropriate speed and controls the water supply pump 3. The discharge pressure becomes the specified value. When the amount of water used decreases, the water pressure in the water pipe 6 increases, the pressure detector l/ detects the increase in water supply pressure, and the signal is sent to the control device l-.
Power to decelerate the variable speed motor 3 is sent from the A, the variable speed motor 3 decelerates ν, the water supply pump I decelerates and the discharge amount decreases, and the signal of the pressure detector -// is restored at the specified water supply pressure. The signal sends the water supply pump to the control device 11! Rotate. The above operating method is the same as the conventional example.

If water is supplied below a certain minimum usage amount, the rotational speed of the variable speed motor and water supply pump I will drop and the efficiency will become extremely low, so set the flow switch at such a flow rate.

When the flow switch operates below the specified minimum water flow, the signal is sent to the control device, and if the signal continues for a certain period of time, the control device sends power to increase the speed of the variable speed motor. The speed of the variable speed motor S is increased, the water supply pump S rotates at an increased speed, and the discharge amount increases. Since the amount of water sent through the water pipe base is small, it flows into the pressure tank d, and the water level in the pressure tank t rises. When the pressure detector // rises to the upper limit specified pressure (normal water pressure gauge - ~ Jkg/cml), the control device /J receives a signal from the pressure detector // and stops the power supply to the variable speed motor. , the water supply pump I stops.

While the water supply pump 3 is stopped, water is supplied from the pressure tank through the water pipe 6. When the water level inside the pressure tank falls and the pressure drops to the specified value, the pressure detection @// outputs a signal, which is sent to the control device /J, the variable speed motor starts, and the water supply pump I moves to the water receiving tank. Pump up water [supply water].

According to the present invention, the water supply pump is not started or stopped frequently when the amount of water used is small, so power consumption is reduced. The pressure tank is small and the pump starts up infrequently. Therefore, equipment costs and running costs are both low, and since the number of times of starting and stopping is small, the lifespan of equipment such as pumps and variable speed motors is extended.

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention. l...Water tank 1...7-to valve 3...Water intake pipe Da...
Variable speed motor 5...Water pump 6...Water pipe-37...
・70-switch t...branch pipe!・・Pressure tank l
/...Pressure detector/Co/control device. Figure 1

Claims (1)

[Scope of Claims] 1. A water pipe to which water is fed by a variable speed water supply pump is equipped with a flow rate detector for detecting the flow rate in the water pipe and a pressure detector for detecting the pressure in the water pipe, and is branched from the water pipe. A variable speed water supply pump system that is equipped with a water pipe system equipped with a pressure tank, and a control device that receives signals from the flow rate detector and pressure detector and controls and drives the variable speed pump 1 in response to the signals. In an operating method in which the variable speed pump is stopped in the water flow range, when the flow rate detector detects a flow rate below the minimum water flow and a certain time period has elapsed, the control device K will temporarily stop the variable speed motor before stopping the variable speed pump. Increase the number of rotations [operate,
It is possible to set the pressure detection value so that it operates at a pressure higher than the fixed supply water pressure, and increase the water level pressure stored in the pressure tank so as to stop the variable speed motor via the control device. A method of operating a variable speed pump characterized by stopping a variable speed motor.