JPH0874776A - Preceding stand-by operation pump - Google Patents

Abstract

PURPOSE: To avoid the generation of an abnormal vibration and a noise in a maintaining operation time, even though the operation is converted from the exhausting operation to the maintaining operation by cutting off the pumping. CONSTITUTION: A lower side impeller chamber 3A and an upper side impeller chamber 3B are formed in the axial direction of a main shaft 1 having a vertical axial line, placing a specific interval, and while the first stage impeller 2A is fixed to the main shaft 1 and inserted rotatable to the lower side impeller chamber 3A, the second stage impeller 2B is fixed to the main shaft 1, and inserted rotatable to the upper side impeller chamber 3B.

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 which avoids adverse effects such as vibration and noise after pumping off.

[0002]

2. Description of the Related Art Conventionally, a pump shown in FIG. 2 has been 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. Side is connected to the suction pipe 5, and the suction pipe 5 is made to communicate with the steam / water switching pipe 6 having a steam / 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 water level signal, and is installed in the water intake well 9. On the other hand, the spindle 1
The discharge elbow 10 is watertightly and rotatably pierced to extend 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 SWL and reaches the pumping start water level RWL, the water / water switching valve 6A is fully opened to perform the air operation. A-. When the pumping start water level RWL is reached, the steam switching valve 6A is fully closed to switch to drainage operation with a predetermined discharge amount, and drainage operation is continued at a water level above the pumping start water level RWL. When the water level of the suction well 9 drops. B-. From the area where the water level exceeds the pumping start water level RWL,
The drainage operation is continued until the pumping start water level RWL is reached and the pumping cutoff water level SWL is lowered. B-. When the water level drops to the pumping cutoff water level SWL, the steam 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 cutoff water level SWL.

By the way, in the conventional preceding standby operation pump, when the drainage operation is switched to the holding operation due to the pumping interruption in B-, the water remaining in the discharge pipe 4 connected to the discharge side of the impeller chamber 3 is retained. A state occurs in which W is supported by the impeller 2 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]

The problem to be solved is that when the drainage operation is switched to the holding operation due to the cutoff of pumping, abnormally large vibrations and noises are generated, and various adverse effects are exerted on the pump equipment. is there.

[0006]

According to the present invention, an impeller fixed to a main shaft, an impeller chamber into which the impeller is rotatably inserted, and a lower upstream side of the impeller chamber are connected. A suction pipe, a discharge pipe connected to the upper downstream side, and a water / water switching pipe provided with a water / water switching valve which is connected to the upstream side of the impeller and connects / shuts off the upstream side from the atmosphere. Further, in the standby operation pump, two impeller chambers are formed with a predetermined interval in the axial direction of the main shaft, and the first-stage impeller is fixed to the main shaft so as to be rotatable in the lower impeller chamber. The present invention is characterized in that the second-stage impeller is fixed to the main shaft and is rotatably inserted into the upper impeller chamber to achieve the purpose of avoiding abnormal vibration and noise during holding operation. .

[0007]

According to the present invention, most of the water remaining in the discharge pipe during the holding operation is supported and agitated by the second-stage impeller, and part of the residual water is supported by the first-stage impeller. It will be stirred. The second-stage impeller has residual water on both the discharge side and the suction side. That is, since the operating state corresponding to the deadline operation is exhibited, larger vibration or noise is not generated in the second-stage impeller. On the other hand, in the first-stage impeller, the pressure of residual water is loaded on the discharge side, and the suction side is opened to the atmosphere, so that the load pressure is small. However, since the residual water in the discharge pipe between the lower impeller chamber and the upper impeller chamber, that is, a small amount of residual water pressure, is loaded on the discharge side of the first-stage impeller, It is possible to suppress the pressure difference between the discharge side and the suction side of the impeller.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing an embodiment of the present invention. Note that the same or corresponding portions as those of the conventional example of FIG.

In FIG. 1, the preceding standby operation pump has a predetermined interval in the axial direction of a main shaft 1 having a vertical axis,
The first-stage impeller 2A is fixed to the lower side thereof, and the second-stage impeller 2B is fixed to the upper side thereof. The first-stage impeller 2A is rotatably inserted into the lower-side impeller chamber 3A, and Step impeller 2A
Is rotatably inserted in the upper impeller chamber 3B. The discharge pipe 4 is connected to the discharge side of the impeller chamber 3A, the suction side of the upper impeller chamber 3B, and the discharge side of the upper impeller chamber 3B, and the suction pipe 5 is connected to the suction side of the lower impeller chamber 3A. The air / water switching pipe 6 having a water / water switching valve 6A connected thereto is connected to the suction pipe 5, and the water level signal detected by the water level detecting means 7 is input to the controller 8 to be controlled based on the input water level signal. The device 8 is configured to output an opening / closing signal to the steam / water switching valve 6A and installed in the water intake well 9. On the other hand, spindle 1
Is watertightly and rotatably pierced through the discharge elbow 10 to extend to the outside and is connected to a prime mover (not shown).

The operation of the standby operation pump thus configured will be described. When the water level in the suction well 9 rises. A-. Until the water level exceeds the pumping cutoff water level SWL and reaches the pumping start water level RWL, the water / water switching valve 6A is fully opened to perform the air operation. A-. When the pumping start water level RWL is reached, the steam switching valve 6A is fully closed to switch to drainage operation with a predetermined discharge amount, and drainage operation is continued at a water level above the pumping start water level RWL. When the water level of the suction well 9 drops. B-. From the area where the water level exceeds the pumping start water level RWL,
The drainage operation is continued until the pumping start water level RWL is reached and the pumping cutoff water level SWL is lowered. B-. When the water level drops to the pumping cutoff water level SWL, the steam 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 cutoff water level SWL.

When the drainage operation is switched to the holding operation by shutting off the pumping at B-, most of the water remaining in the discharge pipe 4, that is, the discharge pipe 4 and the discharge on the downstream side of the upper impeller chamber 3B. A large amount of water remaining in the rising pipe 4A is supported and stirred by the second-stage impeller 2B, and a part of the residual water, that is, between the lower impeller chamber 3A and the upper impeller chamber 3B. The small amount of water remaining in the discharge pipe 4 is supported and stirred by the first-stage impeller 2A. Both the discharge side and the suction side of the second-stage impeller 2B are filled with water. That is, since the operating state corresponding to the deadline operation is exhibited, larger vibration and noise are not generated in the second stage impeller 2B.

On the other hand, in the first-stage impeller 2A, the discharge side is loaded with the residual water pressure, and the suction side is opened to the atmosphere, so that the load pressure is small. However, on the discharge side of the first-stage impeller 2A, residual water in the discharge pipe 4 between the lower impeller chamber 3A and the upper impeller chamber 3B, that is, a small amount of residual water pressure is loaded. Therefore, the pressure difference between the discharge side and the suction side of the first-stage impeller 2A can be suppressed to be small. Therefore, even if the discharge rising pipe 4A is long (high) and the actual lift is high, it is possible to avoid the occurrence of abnormal vibrations and noises, so that various adverse effects are not exerted on the pump equipment.

By using an impeller having a suction performance superior to that of the second-stage impeller 2B as the first-stage impeller 2A, the first-stage impeller 2A and the second-stage impeller having the same suction performance are used. The generation of vibration and noise can be avoided more effectively than when 2B is used.

[0014]

As described above, according to the present invention,
When the drainage operation is switched to the holding operation by shutting off the pumping, a large amount of water remaining in the discharge pipe 4 is supported by the second-stage impeller and stirred, and a small amount of water is supported by the first-stage impeller. The second stage impeller is shut off by agitating to avoid generation of vibration and noise, and in the first stage impeller, by suppressing the pressure difference between the discharge side and the suction side to be small, abnormal vibration and Since the generation of noise is avoided, the pump equipment is not adversely affected in various ways.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a front view showing a conventional example.

[Explanation of symbols]

 1 Spindle 2A 1st-stage impeller 2B 2nd-stage impeller 3A Lower-side impeller chamber 3B Upper-side impeller chamber 6 Air-water switching pipe 6A Air-water switching valve SWL Pumping cutoff water level RWL Pumping start water level

Claims (1)

[Claims] 1. An impeller fixed to a main shaft, an impeller chamber in which the impeller is rotatably inserted, a suction pipe connected to a lower upstream side of the impeller chamber, and an upper downstream side. A standby operation pump comprising: a discharge pipe connected to the impeller; and a steam / water switching pipe provided with a steam / water switching valve that is connected to the upstream side of the impeller and connects / shuts off the upstream side from the atmosphere. Two impeller chambers are formed at predetermined intervals in the axial direction of the main shaft, and the first-stage impeller is fixed to the main shaft and rotatably inserted into the lower impeller chamber, and the second-stage impeller is installed. A standby operation pump characterized in that a vehicle is fixed to the main shaft and is rotatably loaded in the upper impeller chamber.