JPH0861280A - Small water amount management operation device for horizontal shaft mixed flow pump - Google Patents

Abstract

PURPOSE: To perform discharge of air, flowing in a pump flow passage, without using a vacuum pump during small amount of water managing operation. CONSTITUTION: A delivery valve 4 is located in the flow passage on the delivery side of a horizontal shaft mixed flow pump 1 and a bypass pining 23 having one end communicated with the flow passage on the discharge side is arranged in a position situated upper stream from the delivery valve 4. A throttle means 24 is located in the middle of the bypass piping 23. An air bleed pipe 25 having one end communicated with a bypass piping 23 is arranged in a position in the vicinity of a position situated downstream from the throttle means 24. The other end of the air bleed pipe 25 is communicated with the top part of the flow passage on the suction side of the horizontal shaft mixed flow pump 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small water volume control operation device for a horizontal-axis mixed flow pump.

[0002]

2. Description of the Related Art Conventionally, in a pump flow path system as shown in FIG. 2, a suction pipe 2 is connected to the suction side of a horizontal axis mixed flow pump 1 and a discharge pipe built-in heat exchanger 3 is connected to the discharge side. The discharge pipe 5 is connected via the valve 4. The heat exchanger 3 with a built-in discharge pipe is for cooling the refrigerant water of the pump driver 6, has a discharge flow passage for the discharge fluid inside, and arranges a heat transfer pipe around the discharge flow passage. . The heat transfer pipe of the heat exchanger 3 with a built-in discharge pipe communicates with the heat transfer pipe of the cooling jacket of the pump drive machine 6 via the cooling water circulation pipe 7.

The impeller 1a of the horizontal-axis mixed flow pump 1 is connected to a pump driving machine 6 via a main shaft 8, and the main shaft 8 penetrates the pipe wall of the suction pipe 2 at a main-shaft penetrating portion 9. Also,
The discharge passage of the heat exchanger 3 with a built-in discharge pipe has a bypass pipe 10
Through the suction side of the pump.

[0004]

In the above structure, during normal operation, the horizontal axis mixed flow pump 1 is driven by the pump drive unit 6 via the main shaft 7, and the fluid sucked through the suction pipe 2 is built in the discharge pipe type. Discharge from the discharge pipe 5 via the heat exchanger 3 and the discharge valve 4. At this time, while the pump is in operation, the upstream side of the impeller always has a negative pressure, and air flows in from the spindle penetrating portion 9. However, the amount of inflow of this air is small, and in the operation in the state where the discharge valve 4 is fully opened, the flow velocity in the pump is high, and the inflowing air is discharged from the discharge port together with water, which is a problem. There is no such thing.

On the other hand, during the small water management operation performed by closing the discharge valve 4, since the impeller 1a is rotating, the discharge side has a positive pressure, and the discharge fluid is returned to the water source through the bypass pipe 10. ing. At this time, since the diameter of the bypass pipe is generally small, the amount of water that flows back is small, and the flow velocity in the pump is low, so it is difficult to discharge the air that flows in from the main shaft penetrating portion 9 together with water. For this reason, there is a problem that air stays at the top of the pump flow path system such as the suction pipe 2 and induces vibration of the horizontal axis mixed flow pump 1.

The present invention is intended to solve the above-mentioned problems, and a small water quantity control operation device for a horizontal axis mixed flow pump capable of discharging the air flowing into the pump passage during the control operation without using a vacuum pump or the like. The purpose is to provide.

[0007]

In order to solve the above-mentioned problems, a small water quantity control operation device for a horizontal shaft mixed flow pump according to the present invention has a discharge valve provided in a discharge side flow path of the horizontal shaft mixed flow pump. Then, a bypass pipe is provided by communicating one end with the discharge side flow path at a position upstream of the discharge valve, a throttle means is interposed in the middle of the bypass pipe, and one end of the bypass pipe is provided near the downstream side of the throttle means. And an air vent pipe is provided so as to communicate with each other, and the other end of the air vent pipe is communicated with the top of the suction side flow path of the horizontal shaft mixed flow pump.

[0008]

[Operation] With the above-mentioned configuration, during the small water management operation,
The horizontal mixed flow pump is operated with the discharge valve closed. In this state, the discharge fluid discharged from the horizontal axis mixed flow pump is returned to the water source through the bypass pipe or guided to another system.
The flow rate of the discharge fluid flowing through the bypass pipe increases as it passes through the throttle means, a negative pressure is generated in the vicinity of the downstream side of the throttle portion, and the air in the suction side flow path is sucked out through the air vent pipe.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. The basic configuration of this embodiment is the same as that described above with reference to FIG. 2, and members that perform the same operation are designated by the same reference numerals and description thereof is omitted.

In FIG. 1, a bypass pipe port 21 communicating with the internal discharge flow passage is provided at the top of the heat exchanger 3 with a built-in discharge pipe which forms a downstream flow passage of the horizontal axis mixed flow pump 1.
A bypass pipe 23 is connected to the bypass pipe port 21 via an opening / closing valve 22. The tip end side of the bypass pipe 23 communicates with a pit (communication with a water source) P where the suction pipe 2 opens. A throttling means 24 is provided in the middle of the bypass pipe 23, and the throttling means 24 forms a mechanism having functions such as an orifice and an ejector. Bypass piping 23
In the vicinity of the downstream side of the throttle means 24, the air vent pipe 25
Is communicated with the other end of the air vent pipe 25, and the other end of the air vent pipe 25 is communicated with the top of the suction pipe 2 that forms the suction side flow path of the horizontal axis mixed flow pump 1.

The operation of the above structure will be described below.
In normal operation, the discharge fluid sucked up by the drive of the horizontal axis mixed flow pump 1 flows through the discharge passage of the heat exchanger 3 with a built-in discharge pipe, passes through the discharge valve 4, and flows out to the discharge pipe 5.

During a small flow control operation, the horizontal axis mixed flow pump 1 is operated with the discharge valve 4 closed. In this state, a small amount of discharge fluid discharged from the horizontal axis mixed flow pump 1 is returned to the pit P through the bypass pipe 23. The flow velocity of the discharge fluid flowing through the bypass pipe 23 increases as it passes through the throttle means 24, a negative pressure is generated near the downstream side of the throttle portion, and the air in the suction pipe 2 is sucked out through the air vent pipe 25.

Therefore, according to this embodiment, in the small water quantity control operation, the return water passing through the bypass pipe 23 is used to discharge the air in the suction pipe 2, so that another power equipment such as a vacuum pump is used. No need.

[0014]

As described above, according to the present invention, the flow velocity of the discharge fluid passing through the bypass pipe is increased by the throttle means during the small water volume control operation, and the air in the suction side passage is sucked out through the air vent pipe by the ejector effect. As a result, the air flowing into the flow path can be discharged without using a vacuum pump or the like, and it is possible to prevent the occurrence of problems such as vibration due to air retention even in the small water volume management operation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a pump flow channel system of a horizontal axis mixed flow pump according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a pump flow path system of a conventional horizontal axis mixed flow pump.

[Explanation of symbols]

 1 Horizontal Shaft Mixed Flow Pump 2 Suction Pipe 21 Bypass Piping Port 22 On-off Valve 23 Bypass Pipe 24 Throttle Means 25 Air Venting Pipe

Claims (1)

[Claims] 1. A discharge valve is provided in a discharge side flow path of a horizontal axis mixed flow pump, and a bypass pipe is provided by connecting one end to the discharge side flow path at a position upstream of the discharge valve to provide a bypass pipe. An air vent pipe is provided by interposing a throttling means in the vicinity of the downstream side of the throttling means so as to communicate one end with the bypass pipe, and the other end of the air vent pipe is provided at the top of the suction side flow path of the horizontal shaft mixed flow pump. A small water flow control operation device for a horizontal axis mixed flow pump, which is characterized by being connected.