JPH0953592A - Leading standby pump - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To avoid generation of abnormal vibration or noise during holding operation. A valve seat (11) is provided inside a discharge pipe (4), and the valve seat (11) is lifted to a position where it interferes with a stopper (14) using a protection pipe (13) as a guide by the bias of pumping water during pumping operation.
A check valve 12 for supporting the water remaining in the discharge pipe 4 is built in by opening the valve while separating from the valve and by descending by its own weight when the pumping water is shut off and closely closing the valve seat 11. ing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preparatory standby operation pump, and more particularly to a preparatory standby operation pump that avoids the occurrence of harmful effects such as vibration and noise after the pumping is cut off.

[0002]

2. Description of the Related Art Conventionally, a pump shown in FIG. 3 is known as a preceding standby operation pump. In this preceding standby operation pump, an impeller 2 fixed to a main shaft 1 is rotatably loaded into an impeller chamber 3, a discharge pipe 4 is connected to a discharge side of the impeller chamber 3, and suction of the impeller chamber 3 is performed. The suction pipe 5 is connected to the side, and the suction pipe 5 is made to communicate with the water / water switching pipe 6 provided with a water / water switching valve 6A, and the water level signal detected by the water level detecting means 7 is input to the controller 8 and input. The controller 8 is configured to output an open / close signal to the steam / water switching valve 6A based on the generated water level signal and installed in the water intake well 9. On the other hand, the main shaft 1 extends through the discharge elbow 10 in a watertight and rotatably manner and extends to the outside, and is connected to a prime mover (not shown).

A conventional operation example of the preceding standby operation pump configured as described above will be described. When the water level of the water intake well 9 (hereinafter, simply referred to as the water level) rises. A-. Until the water level exceeds the pumping cutoff water level LWL and reaches the pumping start water level HWL, the water / water switching valve 6A is fully opened to perform the air operation. A-. When the pumping start water level HWL is reached, the steam switching valve 6A is fully closed to switch to pumping operation (drainage operation) with a predetermined discharge amount, and pumping operation is continued at a water level above the pumping start water level HWL. To do. When the water level of the suction well 9 drops. B-. From the area where the water level exceeds the pumping start water level HWL,
The pumping operation is continued until the pumping start water level HWL and then the pumping cutoff water level LWL. B-. When the water level drops to the pumping cutoff water level LWL, the steam / water switching valve 6A is fully opened to switch to the holding operation, and the holding operation is continued at the water level below the pumping water cutoff level LWL.

By the way, in the conventional preceding standby operation pump, when the pumping operation is switched from the pumping operation to the holding operation by shutting off the pumping at B-, water remaining in the discharge pipe 4 connected to the discharge side of the impeller chamber 3 is retained. A state occurs in which the impeller 2 is supported and agitated. That is, in the holding operation, a large pressure of residual water is applied to the discharge side (pressure surface) of the impeller 2 and the suction side is open to the atmosphere, so the load pressure is small, that is, the discharge side of the impeller 2 and the suction side. The pressure difference on the side becomes large. In particular, when the discharge riser pipe 4A is long (high) and the actual head is high, the pressure difference is further increased, so that vibrations and noises that are abnormally larger than those during drainage operation are generated, and various pump equipments are generated. There is a drawback that it adversely affects.

[0005]

That is, in the conventional preceding standby operation pump, when the drainage operation is switched to the holding operation by shutting off the pumping, abnormally large vibration and noise are generated, and various adverse effects are exerted on the pump equipment. Was there. Therefore, an object of the invention according to claim 1 is to provide a preceding standby operation pump capable of avoiding generation of abnormal vibration and noise during holding operation.

[0006]

In order to achieve the above object, the invention according to claim 1 has an impeller fixed to a main shaft, and an impeller chamber into which the impeller is rotatably inserted. Standby pump provided with a suction pipe connected to the upstream side of the impeller chamber, a discharge pipe connected to the downstream side of the impeller chamber, and a steam switching pipe connected to the upstream side of the impeller for communication. In the above, the valve seat is provided inside the discharge pipe, the valve seat is opened above the valve seat by the bias of pumping water during the pumping operation, and the valve is opened when the pumping is shut off and the valve seat is brought into close contact with the valve seat. It features a built-in check valve that closes the valve. According to the first aspect of the present invention, during the pumping operation, the check valve is separated above the valve seat by the bias of the pumping water to open the valve to form the pumping passage. On the other hand, when the pumping water is shut off, the check valve descends to come into close contact with the valve seat and close the valve. As a result, the holding operation in which the water remaining in the discharge pipe is supported by the check valve is switched. That is, an operating state corresponding to an idle operation in which there is no pressure difference between the discharge side and the suction side of the impeller is exhibited.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claim 1 will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the invention described in claim 1. The same or corresponding parts as those of the conventional example of FIG. 3 are designated by the same reference numerals and detailed description thereof will be omitted. In FIG. 1, the discharge pipe 4 is formed with an enlarged diameter portion 4B on the upstream side thereof, and a valve seat 11 is provided on the inner periphery of the enlarged diameter portion 4B. The valve 12 is built in the expanded diameter portion 4B so as to be able to move up and down.

As shown in FIG. 2, the check valve 12 is made of a hollow annular body having a central axial hole 12A. Then, as shown in FIG. 1, the protective tube 13 with which the main shaft 1 is covered is inserted into the through hole 12A of the check valve 12 so as to be movable in the axial direction, so that the protective tube 13 is vertically guided and incorporated. Therefore, the stopper 14 restricts the rising. Further, the outer diameter D is set to be slightly smaller than the inner diameter D1 of the discharge pipe 4, and the valve seat 11
It is set to be slightly larger than the inner diameter D2. Further, a relief pipe 16 having a relief valve 16A interposed is provided at the position of the impeller 2, and the relief valve 16A is opened / closed by an opening / closing signal output from the controller 8. Further, a relief pipe 17 is provided on the downstream side of the relief pipe 16, and a relief valve 17A is provided in the relief pipe 17, and the relief valve 17A is opened / closed by an opening / closing signal output from the controller 8.

The operation of the standby operation pump configured as described above will be described. When the water level in the suction well 9 rises. A-. Until the water level exceeds the pumping cutoff water level LWL and reaches the pumping start water level HWL, the water / water switching valve 6A is fully opened to perform the air operation. A-. When the pumping start water level HWL is reached, the steam switching valve 6A is fully closed. Relief valve 1 when pumping operation starts
6A is fully closed, the pumping operation is switched to a predetermined discharge amount, and the pumping operation is continuously performed at a water level equal to or higher than the pumping start water level HWL. When the water level of the suction well 9 drops. B-. From the area where the water level exceeds the pumping start water level HWL,
The pumping operation is continued until the pumping start water level HWL and then the pumping cutoff water level LWL. B-. When the water level drops to the pumping cutoff water level LWL, the steam / water switching valve 6A is opened, and the relief valve 16A is opened to switch to the holding operation. At the water level below the pumping cutoff water level LWL, the air operation is continued. To do. C When the pump is stopped, open the valve 17A to eliminate the water in the pumping pipe.

When the pumping operation is switched to the pumping operation in A- and the pumping is started, the check valve 1 is activated by the urging of the pumping.
As indicated by a phantom line in FIG. 1, the valve 2 rises to a position where it interferes with the stopper 14 and is opened from the valve seat 11 to form a pumping passage.

On the other hand, when the pumping operation is switched from the pumping operation to the holding operation by shutting off the pumping in B-, the check valve 12 descends to the position shown by the solid line in FIG. It will be closed. As a result, the water remaining in the discharge pipe 4, that is, the large amount of water remaining in the discharge pipe 4 and the discharge rising pipe 4A on the downstream side of the impeller chamber 3 is held by the check valve 12. Switch to operation.
That is, an operating state corresponding to an idle operation in which a pressure difference does not occur between the discharge side and the suction side of the impeller 3 is exhibited. Therefore, no larger vibration or noise is generated in the impeller 2. When the pump is stopped, the relief valve 17A is opened to discharge the water in the discharge pipe 4.

[0012]

As described above, according to the first aspect of the invention, when the drainage operation is switched to the air operation by shutting off the pumping, the water remaining in the discharge pipe is removed by the check valve. Since the operation is switched to the supported holding operation and the operating state corresponding to the idle operation in which the pressure difference does not occur between the discharge side and the suction side of the impeller, larger vibration and noise are not generated in the impeller.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the invention according to claim 1.

FIG. 2 is an enlarged half sectional view showing an example of a check valve.

FIG. 3 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 main shaft 2 impeller 3 impeller chamber 5 suction pipe 6 steam switching pipe 11 valve seat 12 check valve

Claims (1)

[Claims] 1. An impeller fixed to a main shaft, an impeller chamber into which the impeller is rotatably inserted, a suction pipe connected to an upstream side of the impeller chamber, and a downstream of the impeller chamber. In a standby operation pump including a discharge pipe connected to the side and a steam switching pipe connected to the upstream side of the impeller, a valve seat is provided inside the discharge pipe, and pumping water during pumping operation is provided. A preceding standby operation pump which is opened by being biased above the valve seat so as to be opened, and which is built in when the pumping is shut off and which is lowered to come into close contact with the valve seat and close the valve. .