JPH0921395A - Pump for preceding waiting operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the generation of an abnormal vibration and a noise, and a trouble such as the wasting of power, in the process changing over from a draining operation to a holding operation through an air-water mixing operation, and in the holding operation, in a short time, by reducing the air-water mixing operation time and the holding operation time. SOLUTION: While the air is led in to the upstream of an impeller 2 from an air-water switching pie 6 when an air-water switching valve 6A is opened, a high pressure water is injected form plural high pressure water injection nozzles 12A, 12A... of a fluid spouting means provided in a suction pipe, in the direction to join to the water flowing in the direction to the impeller 2 while prerotating the suction pipe 5 by the rotation of the impeller 2, and the prerotation of the suction pipe 5 is suppressed, so as to reduce the water flowing amount of the impeller 2.

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 suitable for use in a high-lift preparatory standby operation.

[0002]

2. Description of the Related Art Conventionally, a pump shown in FIG. 5 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, the suction pipe 5 is communicated with the steam / water switching pipe 6 having a steam / water switching valve 6A, and a water level signal detected by the water level detecting means 7 including, for example, a water level gauge is supplied to the controller 8 The controller 8 is configured to output an opening / closing signal to the steam / water switching valve 6A based on the input water level signal and installed in the water intake well 9. On the other hand, the main shaft 1 penetrates the discharge elbow 10 in a watertight and rotatably manner, 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 SWL and reaches the pumping start water level RWL, the air-water switching valve 6A is opened to perform the air operation. A-. When the pumping start water level RWL is reached, the steam / water switching valve 6A is closed to switch to drainage operation at 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-. At the time when the water level drops to the pumping cutoff water level SWL, the air / water switching valve 6A is opened to introduce air into the suction pipe 5,
After the air-water mixing operation, the pump is cut off by breaking the vacuum to switch to the holding operation, and the holding operation is performed at a water level below the pumping cutoff water level SWL, and the residual water in the discharge pipe 4 is dropped over time, and then in the air. Drive.

In the conventional preceding standby operation pump, the B-
When the drainage operation is switched to the holding operation through the steam-water mixing operation by shutting off the pumping in (1), the impeller 2 supports and agitates the water remaining in the discharge pipe 4 connected to the discharge side of the impeller chamber 3. Happens. That is, in the steam-water mixing operation and the holding operation, a large pressure of residual water is applied to the discharge side (pressure surface) of the impeller 2, and a load pressure is small on the suction side, that is, at the outlet side and the inlet side of the impeller 2. The pressure difference becomes large, and vibrations and noises larger than the vibrations during the drainage operation are generated, which has various adverse effects on the pump equipment, and the residual water in the discharge pipe 4 is supported by the impeller 2 and stirred. Therefore, inconvenience such as wasting power is generated.

By the way, even if such an inconvenience occurs, in the case of a preceding standby operation pump having a lift of about 5 m to 10 m, the air (atmosphere) introduced from the steam / water switching pipe 6 to the suction pipe 5 is relatively short. After a steam-water mixing operation and a holding operation, the residual water is dropped to switch to the air operation.
That is, the above-mentioned inconvenience is eliminated in a relatively short time. However, in recent years, there has been a tendency for heavy use (high head is 3
In the preceding standby operation pump, since the impeller 2 having a large centrifugal force component and a high pumping capacity is used, the residual water holding power also becomes large. Therefore, since the steam-water mixing operation and the holding operation time become long, the above-mentioned inconvenience continues for a relatively long time.

On the other hand, as shown in FIG. 6, an impeller 2 fixed to a main shaft 1 is rotatably loaded in an impeller chamber 3, a discharge pipe 4 is connected to the discharge side of the impeller chamber 3, and the blade is Car room 3
The suction pipe 5 is connected to the suction side of the pump and installed in the water intake well 9. The main shaft 1 extends through the discharge elbow 10 in a watertight and rotatably manner to the outside, and is connected to a prime mover (not shown). The preceding standby operation can be performed by.

That is, when the water level of the water intake well 9 rises. A-. The standby operation is performed until the water level reaches the pumping start water level RWL. A-. From the time when the pumping start water level RWL is reached, the drainage operation is performed with a predetermined discharge amount, and the drainage operation is continuously performed 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 pumping is cut off and the operation is switched to the holding operation. At the water level below the pumping cutoff water level SWL, the holding operation is continued,
The remaining water in the discharge pipe 4 is dropped over time, and the standby operation is performed.

Even in this type of preceding standby operation pump, the B
When the drainage operation is switched to the holding operation by shutting off the pumping at −, a state occurs in which the water remaining in the discharge pipe 4 connected to the discharge side of the impeller chamber 3 is supported by the impeller 2 and stirred. That is, the pressure difference between the outlet side and the inlet side of the impeller 2 becomes large, and vibrations and noises larger than the vibrations during the drainage operation are generated, which has various adverse effects on the pump equipment, and the inside of the discharge pipe 4 is adversely affected. Since the impeller 2 supports and agitates the residual water, power consumption and other inconveniences occur. Moreover, in the case of a pump with a high head leading standby operation, the holding operation time becomes long for the same reason as described above, so that vibration and noise larger than the vibration during the drainage operation are generated, which causes various adverse effects on the pump equipment. For a relatively long time.

[0009]

In the conventional pump with a high head preceding standby operation, various adverse effects are exerted on pump equipment due to the process of switching from drainage operation to holding operation due to cutoff of pumping and abnormal vibration and noise during holding operation. And the inconvenience of wasting power was continued for a relatively long time. Therefore, the invention according to claim 1 shortens the steam-water mixing operation time and the holding operation time,
It is an object of the present invention to provide a preceding standby operation pump that eliminates the above inconvenience in a short time. It is an object of the invention according to claim 2 to provide a preceding standby operation pump that solves the above-mentioned inconvenience in a short time by shortening the steam-water mixing operation time and the holding operation time.

[0010]

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. Preceding standby 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 chamber for communication. In the operating pump, fluid ejecting means for ejecting a fluid countercurrent to water flowing in the impeller direction while pre-turning in the suction pipe by the rotation of the impeller is provided. Yes, when pumping is cut off by introducing air from the steam / water switching pipe to the upstream side of the impeller, countercurrent is caused by the operation of the fluid ejection means with respect to the water flowing in the impeller direction while pre-turning inside the suction pipe. By ejecting the fluid to suppress the pre-swirl flow,
Reduce the amount of water flowing to the impeller. As a result, the proportion of air during the air-water mixing operation increases, and the vacuum is quickly broken. That is, it is possible to shorten the air-water mixing operation time and switch to the holding operation, and at the same time, a large proportion of the amount of flowing water, that is, a large amount of air, flows to the discharge pipe side, so that the residual water in the discharge pipe is quickly absorbed. Water can be dropped into the well to shorten the holding operation time. In order to achieve the above object, the invention according to claim 2 has an impeller fixed to a main shaft, an impeller chamber into which the impeller is rotatably inserted, and an upstream side of the impeller chamber. In a preceding standby operation pump including a suction pipe that is opened and a discharge pipe that is connected to the downstream side of the impeller chamber, the impeller rotates while pre-turning in the suction pipe while flowing in the impeller direction. It is characterized by being equipped with a fluid ejection means for ejecting a fluid that flows countercurrently to water.Pre-turning in the suction pipe just before the pumping water is cut off when the water level drops to the pumping cutoff water level. On the other hand, the countercurrent fluid is jetted by the operation of the fluid jetting means to the water flowing in the impeller direction to suppress the pre-swirl flow and reduce the amount of water flowing to the impeller.
This makes it possible to reduce the amount of water on the discharge pipe side during the holding operation, that is, the amount of retained water, to a small amount, so that the residual water in the discharge pipe can be quickly dropped into the water absorption well to shorten the holding operation time. it can.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a front view showing an embodiment of the invention described in claim 1, and FIG. 2 is a sectional view taken along the line AA of FIG. Note that the same or corresponding portions as those of the conventional example shown in FIGS.

In FIG. 1 and FIG. 2, the high-lift head standby operation pump has an impeller 2 fixed to a main shaft 1 and an impeller chamber 3.
Rotatably, the discharge pipe 4 is connected to the discharge side of the impeller chamber 3, the suction pipe 5 is connected to the suction side of the impeller chamber 3, and the steam / water switching valve 6A is connected to the suction pipe 5. The water level detecting means 7 which is a water level gauge is connected to the air / water switching pipe 6 provided therebetween.
The water level signal of the water intake well 9 detected in step S6 is input to the controller 8, and the controller 8 sends the water / water switching valve 6 based on the input water level signal.
It is configured to output an opening / closing signal to A and installed in the water intake well 9. Further, 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) via a coupling 11.

On the other hand, in the suction pipe 5, the impeller 2 is pre-turned in the direction of the arrow R in the suction pipe 5 by the rotation of the impeller 2.
Fluid ejecting means 12 is provided for ejecting a fluid in the direction of arrow r, which flows counter to the water flowing in the direction. The fluid jetting means 12 has a plurality of high-pressure water jet nozzles 12A, 12A ... Which jet high-pressure water in a predetermined direction, and the inlets of the high-pressure water jet nozzles 12A, 12A. The high-pressure water jet nozzles 12A, 12A, ... Are exposed to the inside of the suction pipe 5 by penetrating the pipe wall of the suction pipe 5.

On the other hand, the inlet of the annular header pipe 12B is connected to the outlet of the water conduit 13A of the high-pressure water supply system 13, and the inlet of the water conduit 13A is connected to the high-pressure water supply source (for example, an elevated water tank) 13B. Along with the water conduit 13A
A fluid ejecting means control valve 14 is provided in the. The fluid ejection means control valve 14 is opened and closed by a signal output from the controller 8 based on the water level signal of the water intake well 9 detected by the water level detection means 7.

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 air / water switching valve 6A is opened to perform air operation, and the fluid ejection means control valve 14 is closed to eject the fluid. The operation of the means 12 is stopped. A-. When the pumping start water level RWL is reached, the steam switching valve 6A is closed to switch to pumping operation (drainage operation), and drainage operation is continued at a water level above the pumping start water level RWL.
Also in this case, the operation of the fluid ejecting means 12 is stopped. 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, this water level is detected by the water level detecting means 7, the detected water level signal is input to the controller 8, and the controller 8 sends the water / water switching valve 6A based on the input water level signal. A valve open signal is output to the valve to open the steam / water switching valve 6A. At the same time, the controller 8 outputs a valve opening signal to the fluid ejection means control valve 14 to open the fluid ejection means control valve 14.

When the steam / water switching valve 6A is opened, air is introduced from the steam / water switching pipe 6 to the upstream side of the impeller 2. Also,
By opening the fluid ejecting means control valve 14, the high pressure water supply system 1
High-pressure water is introduced from the high-pressure water supply source 13B of No. 3 through the water guiding pipe 13A into the annular header pipe 12B of the fluid ejection means 12, and ejected from the plurality of high-pressure water injection nozzles 12A, 12A. These plural high-pressure water jet nozzles 12A, 1
The injection direction of the high-pressure water ejected from 2A ... is in the direction of arrow r, which flows counter to the water flowing in the direction of the impeller 2 while pre-turning in the direction of arrow R in the suction pipe 5 by the rotation of the impeller 2. Since it is oriented, the pre-swirl flow of the suction pipe 5 is suppressed, and the amount of water flowing to the impeller 2 is reduced. As a result, the proportion of air during the air-water mixing operation increases, and the vacuum is quickly broken. That is, the air-water mixing operation time can be shortened to switch to the holding operation, and at the same time, a large proportion of the amount of flowing water, that is, a large amount of air, flows to the discharge pipe 4 side, so that the residual water in the discharge pipe 4 is removed. Immediately suction well 9
It is possible to reduce the holding operation time by dropping the water. As a result, the process of switching from the drainage operation to the holding operation through the water-water mixing operation due to pumping interruption and the abnormal vibration and noise that occurred during the holding operation may cause various adverse effects on the pump equipment and waste power. Inconvenience can be resolved in a short time.

FIG. 3 is a front view showing an embodiment of the invention described in claim 2, and FIG. 4 is a sectional view taken along the line BB in FIG. 2. The same reference numerals are given and detailed description is omitted.

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 reaches the pumping start water level RWL, the standby operation is performed, the fluid ejection means control valve 14 is closed, and the operation of the fluid ejection means 12 is stopped. A-. From the time when the pumping start water level RWL is reached, the drainage operation is performed with a predetermined discharge amount, and the drainage operation is continuously performed at a water level above the pumping start water level RWL. Also in this case, the operation of the fluid ejecting means 12 is stopped. 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 pumping is cut off and the operation is switched to the holding operation. Shortly before the pumping is interrupted, the controller 8 outputs a valve opening signal to the fluid ejecting means control valve 14 so that the fluid ejecting means control valve 14
Open the valve.

By opening the fluid jetting means control valve 14, the high pressure water supply source 13B of the high pressure water supply system 13 to the water conduit 13A.
High-pressure water is introduced into the annular header pipe 12B of the fluid ejection means 12 through the plurality of high-pressure water injection nozzles 12A, 1A.
2A ... The direction of injection of the high-pressure water ejected from the plurality of high-pressure water injection nozzles 12A, 12A ... Is flowing in the impeller 2 direction while pre-turning in the suction pipe 5 in the direction of the arrow R by the rotation of the impeller 2. Since it is directed in the direction of the arrow r that flows counter to the water, the pre-swirl flow of the suction pipe 5 is suppressed, and the amount of water flowing to the impeller 2 is reduced. This makes it possible to reduce the amount of water on the discharge pipe side during the holding operation, that is, the amount of retained water, to a small amount, so that the residual water in the discharge pipe can be quickly dropped into the water absorption well to shorten the holding operation time. it can. As a result, it is possible to eliminate inconveniences such as abnormal vibrations and noises generated during the holding operation, which have various adverse effects on the pump equipment and waste of power.

[0020]

As described above, according to the first aspect of the present invention, when pumping is interrupted by introducing air from the water / water switching pipe to the upstream side of the impeller, the impeller direction is preliminarily swirled in the suction pipe. The countercurrent flow is jetted by the operation of the fluid jetting means to the water flowing in the air to suppress the pre-swirling flow and reduce the amount of water flowing to the impeller, thereby reducing the air flow during the air-water mixing operation. By increasing the ratio of the above, it is possible to shorten the air-water mixing operation time and switch to the holding operation, and a large amount of air with a large ratio to the flowing water flows to the discharge pipe side, so that the residual water in the discharge pipe is removed. Since it is possible to quickly drop the water into the intake well and shorten the holding operation time,
The process of switching from drainage operation to steam-water mixing operation to holding operation due to pumping interruption and abnormal vibration and noise generated during holding operation have various adverse effects on pump equipment and waste of power. It can be resolved in time. According to the invention described in claim 2,
Just before the pumping water is cut off and the pumping water is cut off, the water flowing in the direction of the impeller while pre-turning inside the suction pipe is moved to the countercurrent fluid by the operation of the fluid jetting means. The amount of water on the discharge pipe side during holding operation, that is, the retained water amount can be reduced to a small amount by jetting it to suppress the pre-swirling flow and reducing the amount of water flowing to the impeller. Water can be quickly dropped into the intake well to shorten the holding operation time. Accordingly, it is possible to eliminate inconveniences such as abnormal vibrations and noises generated during the holding operation, which have various adverse effects on the pump equipment and waste of power.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a front view showing an embodiment of the invention according to claim 2.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

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

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

[Explanation of symbols]

 1 main shaft 2 impeller 3 impeller chamber 4 discharge pipe 5 suction pipe 6 steam switching pipe 12 fluid ejection means

Claims (2)

[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 preceding standby operation pump having a discharge pipe connected to the side of the impeller and a steam switching pipe connected to the upstream side of the impeller chamber, the impeller is pre-turned in the suction pipe by the rotation of the impeller. A preceding standby operation pump, characterized in that a fluid jetting means for jetting a fluid flowing countercurrently to the water flowing in a predetermined direction is provided. 2. 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 preceding standby operation pump having a discharge pipe connected to the side, a fluid jet for jetting a fluid countercurrent to water flowing in the impeller direction while pre-turning in the suction pipe by rotation of the impeller. A preceding standby operation pump characterized in that means is provided.