JP3241963B2 - Variable speed water supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable speed water supply device,
In particular, the present invention relates to a so-called direct connection type variable speed water supply device which is directly connected to a terminal water supply device from a water distribution pipe via a pressure pump.

[0002]

2. Description of the Related Art FIG. 1 shows a system outline of a direct connection type variable speed water supply apparatus. For example, an inflow pipe 12 is connected to a water distribution pipe 11, which is a main pipe of water supply, and a pressurizing pump 13 is connected to the inflow pipe. A water meter 15 is connected to the inflow pipe 12, and the used water amount is measured. A discharge pipe 18 connected to a terminal water supply device 17 is connected to the discharge side of the pressure pump 13. The discharge pipe 18 has a flow switch 19,
The discharge side pressure tank 20 and the like are connected. Further, a discharge pressure detector 23 is provided on the discharge side of the pressurizing pump 13,
The discharge side pressure signal is sent to the control unit 22.

The pump 13 is driven at a variable speed by an electric motor via a frequency / voltage converter (inverter) 25 connected to a three-phase 200 V commercial power supply. Control unit 22
Sends a signal to the variable speed driving means 25 based on the signal of the discharge pressure detector 23 to control the speed of the pump 13 to increase or decrease to an arbitrary speed.

In such a direct connection type variable speed water supply device,
There are various merits as compared with connecting a water storage tank to a conventional water distribution pipe and distributing the water stored in the water storage tank to the terminal water supply equipment using a pressure pump. The advantage is that since no water storage tank is provided, the size of the water supply device can be reduced as a whole, and the installation area can be reduced. Also, since no water is stored,
Sanitary preferred. Furthermore, since the water pressure of the water distribution pipe can be used as it is on the suction side of the pressure pump, the head of the pressure pump is reduced, and energy can be saved accordingly.

However, in a conventional variable speed water supply device using a water storage tank, the inflow side of the pressure pump is connected to the water storage tank, and the upper part of the water storage tank is open to the atmosphere. For this reason, only the pressure based on the water level of the water storage tank is applied to the pressure on the inflow side of the pressurizing pump. For this reason, even when the flow rate on the discharge side of the pump is zero, it is customary to continue the operation with a pump lower limit speed in order to maintain the minimum pressure on the discharge side.

However, in a direct connection type variable speed water supply device, the inflow pressure on the inflow side of the pump largely depends on the water pressure in the water distribution pipe, and thus may exceed the set discharge pressure of the pump. In such a case, if the operation is continued at the above-described pump lower limit speed, the water pressure in the terminal water supply device is excessively increased, which not only causes careless inconvenience to the user side, but also wastes energy. It was not preferable from the viewpoint of energy saving.

[0007]

Problems to be Solved by the Invention
No. 6 discloses a direct connection type variable speed water supply device having a configuration schematically shown in FIG. Then, provided the pressure detector on the inflow side of the pump, the inflow pressure of the pump is higher constant the above set pressure to stop the pump, setting the pressure consists of more than a certain low above problems by restarting the pump Techniques to circumvent are disclosed.

FIG. 5 shows this control flow. Control apparatus first reads the inflow side pressure P _S of the pump. And
More than a fixed pressure α than the discharge set pressure P1, the inflow pressure P _S
If the pressure is high, stop the pump. And the inflow pressure P
_The pump is restarted when _S falls below the set pressure P1 below a certain pressure α. In the case where the suction pressure P _S is in the meantime, control of the discharge pressure constant is performed.

FIG. 6 shows an example of such a pump start / stop control result. The pump restart is performed when the suction side pressure P _S is below a predetermined pressure α than the discharge set pressure P1, and decreases the discharge pressure when the pump as shown stop, a predetermined pressure at the end the water supply device Can not be supplied.

The present invention has been made in view of the above circumstances, and when the inflow pressure of a pump rises, the operation of the pump is reliably stopped with a simple configuration, and the extra water pressure to the terminal water supply equipment is reduced. It is an object of the present invention to provide a direct connection type variable speed water supply device capable of avoiding the rise of the water.

[0011]

[0012]

SUMMARY OF THE INVENTION A variable speed water supply device according to the present invention is connected to an inflow pipe connected to a water distribution pipe, a pressurized pump connected to the inflow pipe, and connected to a discharge side of the pressurized pump. A discharge pipe connected to a terminal water supply device, a discharge pressure detector for detecting a discharge pressure of a pressurizing pump provided in the discharge pipe, a variable speed driving means for driving the pressurizing pump at a variable speed, and Control means for controlling the operation of the pump at a variable speed, wherein the control means reduces the pump speed when the pump discharge pressure is higher than the discharge set pressure so that the pump discharge pressure becomes a predetermined discharge set pressure. A discharge pressure control means for increasing the pump speed when the pump discharge pressure is lower than the set discharge pressure to continuously control the speed of the pump;
If, when the pump discharge pressure becomes a pressure higher than the discharge set pressure pressure inlet side of the pump is increased, the means you stop by decelerating the pump speed to zero, the
The pump discharge pressure is lower than the discharge set pressure.
And a means for restarting the pump when the pump is turned off.

[0013]

[0014]

Further, the pressure pump further includes a bypass pipe communicating with the inflow side and the discharge side of the pressurizing pump, and a check valve which is inserted into the pipe to prevent a backflow from the discharge side to the inflow side. And

[0016]

When the pressure on the inflow side of the pump rises and the discharge pressure of the pump becomes higher than the set pressure, the pump is decelerated until the pump stops. No more. For this reason, the water pressure to the terminal water supply equipment can be reliably prevented from rising, and unnecessary pump operation can be prevented to save energy. When the pump discharge side pressure drops to the discharge set pressure P1,
The pump is immediately restarted and operated so that the discharge pressure reaches the set pressure. Therefore, the problem that the discharge pressure decreases during the pump stop period is prevented.

Further, it is possible to control the pump stop when the inflow pressure rises with the pressure detector only on the discharge side of the pump.
For this reason, the pressure detector on the inflow side becomes unnecessary, or if it is necessary for detecting the decrease in the inflow-side water pressure, the accuracy can be reduced. Note that a pressure detector is originally required on the discharge side of the pump for discharge control for keeping the discharge pressure constant, and this pressure detector can be shared.

Further, since the bypass pipe and the check valve are provided, when the pump is stopped and the inflow pressure is higher than the discharge pressure, the inflow pressure can be supplied to the discharge side without causing pressure loss of the pump. Conversely, when the inflow pressure decreases, the backflow is prevented by the check valve, and when the discharge pressure becomes equal to or lower than the set discharge pressure, the pump is started and the discharge pressure becomes a constant set pressure. Operation is resumed at

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In the drawings, the same reference numerals indicate the same or corresponding parts.

Also in this embodiment, the system configuration in which the pressure pump 13 is directly connected to the water distribution pipe 11 and supplies water to the terminal water supply equipment 17 is as shown in FIG. In this embodiment, the pressurizing pump 13 increases and decreases the pump rotation speed by the variable speed driving means 25 so that the supply water pressure to the terminal water supply device 17 becomes constant by the signal of the discharge pressure detector 23. discharge pressure control is performed to control the discharge pressure P _d at a constant pressure P1. In addition, a bypass pipe 14 that connects the discharge side and the inflow side of the pump 13 is connected, and forms a flow path that bypasses the pump 13. Each of the bypass pipe 14 and the discharge pipe 18 is provided with a check valve (check valve) 16.

FIG. 2 shows a configuration of a control portion of the variable speed water supply device according to one embodiment of the present invention. The control unit 22, the pressure P _d of the discharge side of the discharge pressure detector 23 pressure pump 13 is input. The set pressure P1 is a control target value of the discharge pressure, and is usually set to ² to 3 kg / cm ² .

FIG. 3 shows a flow of the discharge pressure control. The discharge pressure P on the discharge side of the pump 13 from the discharge pressure detector 23
_d is read and compared with the set pressure P1. Discharge pressure P _d
Is higher than the set pressure P1, a deceleration command is issued to gradually reduce the pump speed to zero. Further, when the discharge pressure P _d detected by the discharge pressure detector 23 is lower than the set pressure P1 which is the target value, issues a speed increase instruction to increase the pump speed, increasing the pump 13 by the variable speed drive means 25 Hayashi, close the discharge pressure P _d the set pressure P1 which is the target value. When the pump speed is zero, that is, when the pump is stopped, the pump starts and gradually increases its speed.

[0023] Figure 4 shows an example of the control result of the discharge pressure P _d by the variable speed water supply apparatus of an embodiment of the present invention. Inlet pressure P _s is lower than the discharge set pressure P1, the control unit 22 according to the flow shown in FIG. 3, so that the P _d = P1, the pump speed is controlled by the variable speed drive 25. As a result, the discharge pressure of the pump is maintained at a substantially constant pressure P1.

[0024] For example, when the inflow pressure of the pump 13 by water pressure rises in the water pipe 11 reaches the discharge set pressure P1, if the pump speed is not zero, the discharge pressure P _d becomes higher than P1. In this case, a deceleration command is issued from the control unit 22 to the variable speed driving device 25 in accordance with the control flow shown in FIG. The pump 13 is gradually decelerated to zero speed, and then stops. In this state, the inflow pressure is directly supplied to the discharge side through the bypass pipe 14, and the discharge pressure becomes substantially equal to the inflow pressure.

[0025] Then, with a decrease or the like of the water pressure in the water pipe 11, the discharge pressure P _d in a state where the pump 13 has stopped, when falls below the discharge set pressure P1, P _d <P1 becomes the procedure shown in FIG. 3, A speed increase command is issued to the pump 13, and the pump 13 restarts. The pump is gradually accelerated, the discharge pressure P _d reaches the set pressure P1. After that, pump 1
Rotational speed of 3 is increased or decreased, the discharge pressure P _d is controlled so as to set the discharge pressure P1.

As described above, according to the present invention, when the inflow pressure of the pump increases and pressurization by the pump is not necessary, the start and stop of the pump are controlled as part of the discharge pressure control of the pump.

[0027] In the embodiment described above, if the discharge pressure P _d exceeds the set pressure, an example has been described in which the pump is stopped, and the accumulator to the accumulator tank further predetermined time pressurized during small amount of water Of course, the operation of the pump may be stopped later.

[0028]

As described above, according to the present invention, when the inflow pressure of the pump rises and the discharge pressure exceeds the set pressure in the direct connection type variable speed water supply device,
The pump is immediately stopped, and when the inflow pressure decreases and the discharge pressure falls below the set pressure, the pump can be restarted immediately. Therefore, it is possible to avoid the problem of a decrease in water pressure in the terminal water supply device while achieving energy saving at the time of excessive inflow pressure. Further, since the inflow-side pressure sensor is unnecessary or does not require accuracy, the cost of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a system configuration of a direct connection type variable speed water supply device.

FIG. 2 is an explanatory diagram of a control system of the variable speed water supply device according to one embodiment of the present invention.

FIG. 3 is a flowchart of discharge pressure control according to one embodiment of the present invention.

FIG. 4 is a graph showing an example of a control result by the variable speed water supply device according to the embodiment of the present invention.

FIG. 5 is a flowchart showing an example of conventional control at the time of excessive inflow pressure.

FIG. 6 is a graph showing an example of a control result according to the above flow.

[Explanation of symbols]

22 control unit 23 discharge pressure detector 25 variable speed drive means (inverter) P _S inflow pressure P _d the discharge pressure P1 discharge set pressure

Claims (2)

(57) [Claims] 1. An inflow pipe connected to a water distribution pipe, a pressurized pump connected to the inflow pipe, a discharge pipe connected to a discharge side of the pressurized pump and connected to a terminal water supply device, A discharge pressure detector that detects a discharge pressure of a pressurizing pump provided in a discharge pipe, a variable speed driving unit that drives the pressurizing pump at a variable speed, and a control unit that controls the pump at a variable speed. control means, so that the discharge set pressure pump discharge pressure predetermined, when the pump discharge pressure is higher than the discharge set pressure decreases the pump speed when the pump discharge pressure is lower than the discharge set pressure A discharge pressure control means for continuously controlling the speed of the pump by increasing the pump speed, and when the pressure on the inflow side of the pump increases and the pump discharge pressure becomes higher than the discharge set pressure. , The pump Means stop by decelerating the degree up to zero, the Pont
The discharge pressure became lower than the discharge set pressure.
Means for restarting the pump when the time has elapsed. 2. The apparatus according to claim 1, further comprising a bypass pipe connected to the inflow side and the discharge side of the pressurizing pump, and a check valve inserted into the pipe to prevent a backflow from the discharge side to the inflow side. variable speed water supply apparatus according to claim 1 Symbol mounting and.