JPH05331886A - Automatic water supply unit of water tank - Google Patents

Abstract

PURPOSE:To prevent a rise of the pressure more than a set pressure for stopping a pump by providing a discharge pressure control device connected to a pump in a water tank, outside the water tank, and providing a solenoid valve to a bypass pipe provided striding the pressure reducing valve of the control device. CONSTITUTION:To discharge flanges 101 of pumps in a water tank, spherical flexible joints 102 are connected, and a discharge pipe is connected to a main pipe 105 on the way from the joints 102. And a bypass pipe 107 is connected to the main pipe 105 by striding a pressure reducing valve 106 provided on the way of the main pipe 105, and a pressure switch and pressure accumulating tanks 110 are provided at the near side of a sluice valve 108 provided at the end of the main pipe 105. When the pressure in the main pipe 105 exceeds a set pressure for stopping a pump, the switch is operated by the pressure reducing valve 106 so as to stop the pump. Furthermore, the solenoid valve 1 is closed, the pressure reducing valve 106 is also closed, and the pressure is increased passing through the bypass pipe 107. The pressure in the pipe is made lower than the set pressure for stopping the pump during the period from the time when the switch is made at a stopping pressure to the time of stopping the pump.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic water supply unit for a water tank in which a pump is installed inside the water tank and a discharge pressure control device connected to the pump is installed outside the water tank.

[0002]

2. Description of the Related Art An automatic water supply unit for a water tank having a pump installed in the water tank and a discharge pressure control device 100 connected to the pump outside the water tank is shown in FIGS. 5 and 6. .. This is a ball-shaped flexible joint 102 in which a ball-shaped flexible joint 102 is connected to a discharge flange 101 of a pump (not shown) in a water tank.
A discharge pipe 104 provided with a check valve 103 on the way from 2 is connected to a water supply main pipe 105. A pressure reducing valve 106 is provided in the middle of the water supply main pipe 105, and a bypass pipe 107 is connected to the water supply main pipe 105 across the pressure reducing valve 106. A sluice valve 108 is provided at the tip of the water supply main pipe 105, and a pressure switch 109 and a pressure accumulator tank 110 are provided in front of the sluice valve 108. The bypass pipe 107 is for reducing the frequency of starting and stopping the pump when the amount of water is small, and the accumulator tank 110 is also for reducing the frequency of starting and stopping the pump and stabilizing the discharge pressure.

[0003]

In the conventional automatic water supply unit, when the pressure becomes higher than the pump stop set pressure set as necessary, the delay timer is activated by the pressure switch 109, and the pump is stopped after a certain period of time. I am letting you. However, in this case, since the pressure of the pump is applied to the main water supply pipe 105 through the bypass pipe 107 as it is until the pump is stopped after the pressure reducing valve 106 is closed, the stop pressure rises to the pump cutoff pressure (Fig. 4). If a device with low pressure resistance (boiler, etc.) is installed in the terminal, the stop pressure will increase no matter how much the water supply pressure is adjusted.

Therefore, an object of the present invention is to provide an automatic water supply unit for a water tank in which the pipe internal pressure does not rise above the pump stop set pressure from the time the pressure reducing valve is closed until the pump is stopped. To do.

[0005]

In order to achieve the above object, the present invention provides an automatic water supply unit for a water tank in which a pump is installed inside the water tank and a discharge pressure control device connected to the pump is installed outside the water tank. A bypass pipe is provided across the pressure reducing valve provided in the discharge pressure control device, and an electromagnetic valve is provided in the bypass pipe.

[0006]

According to the present invention, the pump is stopped by the pressure switch when the pressure in the pipe becomes higher than the set pressure for stopping the pump. At this time, the pressure switch closes the solenoid valve.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In the embodiment of the present invention shown in FIGS. 1 and 2, a spherical flexible joint 102 is connected to a discharge flange 101 of a pump (not shown) in a water tank in the same manner as in the conventional case, and the spherical flexible joint 102 is reversed in the middle. A discharge pipe 104 provided with a stop valve 103 is connected to a water supply main pipe 105. A pressure reducing valve 106 is provided in the middle of the water supply main pipe 105, and a bypass pipe 107 is connected to the water supply main pipe 105 across the pressure reducing valve 106. A sluice valve 108 is provided at the end of the main water supply pipe 105, and a pressure switch 109 and a pressure accumulator tank 110 are provided in front of the sluice valve 108. When the pipe pressure in the main water supply pipe 105 ahead of the pressure reducing valve 106 becomes higher than the pump stop set pressure, the pressure switch 10
9 operates to stop the pump in the water tank (not shown).
In the present invention, the bypass pipe 107 is provided with the solenoid valve 1, and the solenoid valve 1 is also closed when the pressure switch is actuated. Therefore, the pressure reducing valve 106 is closed, the pressure rises through the bypass pipe 107, and the pressure switch 109
During the period from the stop pressure of 1 to the stop of the pump, the pressure of the pump is not directly applied to the main water supply pipe 105 through the bypass pipe 107. The bypass pipe 107 is set to have a diameter smaller than that of the water supply main pipe 105 because it is necessary to maintain the water supply pressure high to some extent when the required amount of water is small, and the pressure reducing valve 106 installed in the water supply main pipe 105 is closed. Water is passed through the bypass pipe 107. Valves are provided before and after the solenoid valve 1.

[0008]

As described above, according to the present invention, since the bypass pipe is provided across the pressure reducing valve provided in the discharge pressure control device, and the electromagnetic valve is provided in the bypass pipe, the pressure switch is actuated. With the solenoid valve closed,
The pressure inside the pipe will not rise above the pump stop set pressure,
Even if a device having a low pressure resistance, such as a boiler, is installed in the terminal, a separate pressure reducing valve is not required in front of the device, and the device is not adversely affected. Further, it is possible to control the pressure in the pipe and reduce the number of times of starting and stopping the pump. Further, the pressure tank may be small as in the conventional case, and the cost of the entire automatic water supply unit is reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a portion of a discharge pressure control device showing an embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a graph showing a pump performance curve of the present invention.

FIG. 4 is a graph showing a pump performance curve of a conventional example.

FIG. 5 is a plan view showing a conventional example.

FIG. 6 is a front view showing a conventional example.

[Explanation of symbols]

 1 Solenoid valve 100 Discharge pressure control device 106 Pressure reducing valve 107 Bypass pipe

Claims (1)

[Claims] 1. An automatic water supply unit for a water tank in which a pump is installed in the water tank and a discharge pressure control device connected to the pump is installed outside the water tank, and a bypass pipe across a pressure reducing valve provided in the discharge pressure control device. An automatic water supply unit for a water tank, characterized in that a solenoid valve is provided in this bypass pipe.