JP2673740B2 - Operating method of vertical pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for operating a vertical shaft pump, and more particularly to a method for operating a vertical shaft pump in a drainage well installed in a waterway or in a rainwater pump facility. Regarding

(Prior Art) Water that has flowed into an intake well of a drainage pump station is often discharged by pumping operation of one or more vertical shaft pumps arranged in the intake well.

In this case, these pumps are generally of the same type, and the impellers are all installed at the same level.

In this way, by using the same type of pump and by installing all the impellers at the same level,
Since the pumps can be interchanged with each other, it becomes easy to manage replacement parts that must be replenished in the event of aged deterioration or failure. Further, it is possible to avoid the inconvenience that the specific pump is used more frequently, the pumping operation time is longer than that of other pumps, and deterioration is accelerated.

(Problems to be Solved by the Invention) However, in the conventional method, the pumping operation cannot be performed unless the water level rises to the impeller position.

Also, when using multiple vertical pumps for drainage,
When the water level of the pump suction well rises and reaches the impeller installation level while all the pumps are operating in the air, at this point all the pumps will start pumping operation and drain. In this case, if the total drainage amount of all pumps is larger than the inflow water amount to the pump suction well, the water level will drop to the pumping cutoff level in a single hour, and the operation will be switched to the air operation again. That is, the operating state is frequently switched between the aerial operation and the pumping operation in a short cycle, which may be one of the causes for shortening the life of the pump.

The first aspect of the present invention has been made in view of the above circumstances, and it is efficient and effective to use a very small amount of sealing water even when the water level is below the installation level of the impeller, in response to a request for drainage. It is an object of the present invention to provide a method for operating a vertical shaft pump that can be transferred to a predetermined pumping operation, and in addition to the above object, the second invention reduces pump life due to frequent switching of operating states. It is an object of the present invention to provide a method for operating a vertical shaft pump that can be reliably prevented.

(Means for Solving the Problems) In order to achieve the above object, the first aspect of the present invention is a method of operating a vertical shaft pump, in which an impeller is arranged above a pumping cutoff water level specific to the pump. The blade gap formed between the outer circumference of the impeller of the pump and the inner circumference of the impeller are directly communicated with the water source for water sealing by the water supply pipe for water sealing, and the water level rises to reach the water impeller. The vertical pump is pumped at a water level lower than the installation position of the impeller by previously supplying the sealing water from the sealing water source to the blade gap via the sealing supply pipe to seal the blade gap. It is characterized by.

Further, the second invention is a method of operating a plurality of vertical pumps in which an impeller is arranged in a suction well at a level higher than a pumping water cutoff level specific to the pump, and each of the plurality of vertical pumps is provided. Before the blade gap formed between the outer circumference of the impeller and the inner circumference of the impeller and the water source for sealing water are directly communicated with each other by the water supply pipe for water sealing, the water level rises and the water level reaches the impeller. The vertical shaft pump selected from among all vertical shaft pumps is supplied with the sealing water from the water source for sealing water through the water supply pipe for sealing water into the blade gap of the vertical shaft pump to seal the blade gap. The feature is that the pumping operation is performed at a water level lower than the installation position of the impeller.

(Operation) According to the first aspect of the present invention, the sealing water is directly supplied from the sealing water source to the blade gap of the vertical pump operating in the air through the sealing water supply pipe to seal the blade gap. As a result, the self-sufficiency of the vertical shaft pump is enhanced, and it is possible to pump the vertical shaft pump at a water level lower than the installation position of the impeller.At this time, the sealing water is directly supplied to the blade gap. By supplying a small amount of sealing water, the self-priming ability of the pump can be effectively increased, the time until the start of drainage can be shortened, and the pumping operation can be switched to a predetermined pumping operation very quickly and efficiently. .

Further, according to the second aspect of the present invention, one or more vertical shaft pumps are selected from the plurality of vertical shaft pumps operating in the air according to the amount of water flowing into the intake well, and the selected vertical pumps are selected. The self-sufficient capacity of the vertical pump is enhanced by directly supplying the sealing water from the source for sealing water through the water supply pipe for sealing to the blade gap of the vertical pump to enhance the self-sufficiency of the vertical pump. It is possible to perform the pumping operation in stages at a water level lower than the installation position of the impeller. In other words, it is possible to set the pumping start water level of a plurality of pumps to different water levels and avoid the situation where all pumps start pumping at the same time. Therefore, the operating state can be frequently switched between the aerial operation and the pumping operation. There is no reduction in pump life. Further, as in the case of the first aspect of the invention, the self-priming ability of the pump can be effectively enhanced by supplying only a small amount of sealing water, and the time until the start of drainage can be shortened, resulting in a very quick and efficient predetermined pumping. You can switch to driving.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram showing a system example of a vertical pump and a water supply system for sealing water applied to the implementation of the first invention. In the figure, a vertical pump 2 of a vertical pump 2 arranged in a pump suction well 1 of a drainage pump station is shown. The position of the impeller 20 is set higher than the pumping cutoff water level (minimum water level) LWL of the intake well 1, and normally,
The pumping operation can be performed when the water level reaches the impeller. Further, the vertical pump 2 is opened by the water level detection signal from a water level sensor (not shown) when the water level of the suction well 1 drops to the pumping cutoff water level LWL lower than the impeller set water level HWL. Through 3,
Atmosphere is introduced into the upstream pipe line (suction bellmouth) 5 upstream of the impeller 20, and vacuum operation caused by this causes a switch to air operation.

The blade gap 7 formed between the outer circumference of the impeller 20 and the inner circumference of the impeller chamber 4 is supplied to a water source (pump) 9 for sealing water via a water supply pipe 8 for sealing water provided with a valve 6. It is in communication.

 Next, the operation will be described.

When the water level of the pump water supply well 1 is below the pumping cutoff water level LWL and the vertical axis pump 2 is operating in the air, the amount of water flowing into the pump suction water well 1 increases and slightly exceeds the pumping water cutoff level LWL ( When drainage is requested at a position lower than the position of the impeller 20, the water / water switching means 3 is closed to cut off the communication between the impeller upstream pipe line 5 and the atmosphere. Next, the valve 6 of the water supply pipe 8 for sealing water is opened, and the blade gap 7 is sealed by the operation of the water source 9 for sealing water. As a result, the self-priming ability of the pump is enhanced and the pumping operation is switched. That is, pump 2
The pumping operation can be performed at a water level lower than the position of the impeller 20.

FIG. 2 is an explanatory view showing an arrangement of vertical shaft pumps and a system example of a water supply system for sealing water applied to the implementation of the second invention. In the figure, a plurality of pump water intake wells 1 (for example, three) ) Vertical shaft pumps 2A, 2B, 2C are arranged. The positions of the impellers 2a, 2b, 2c of these pumps are set to the same level. That is, the impeller set water level HWL of each pump 2A, 2B, 2C is unified, and normally the water level is set to the impellers 2a, 2b, 2
Both pumps are ready for pumping when they reach c. In addition, each pump 2A, 2B, 2C is a suction well 1
When the water level of the water drops to the pumping cutoff level LWL, through the water / water switching means 3 which is opened by a water level detection signal from a water level sensor (not shown), the upstream pipe lines (suctions) upstream of the impellers 2a, 2b, 2c Atmosphere is introduced into the bell mouth (5), and the vacuum break caused by the atmosphere is switched to the air operation. The blade gaps 7a, 7b, 7c formed between the outer circumferences of the impellers 2a, 2b, 2c and the impeller chambers 4A, 4B, 4C are water supply pipes for sealing water provided by the valves 6A, 6B, 6C. It communicates with a water source (pump) 9 for sealing water via 8.

 Next, the operation will be described.

When the water level of the pump intake well 1 is below the pumping cutoff water level LWL and each vertical pump 2A, 2B, 2C is operating in the air, it is possible to secure the discharge amount that is approximately equivalent to the inflow amount to the pump intake well 1. Select the number of pumps. For example, if the amount of inflow water is approximately equivalent to the displacement of one pump, select pump 2A, and when the water level reaches WL1 which is the same as or slightly higher than the pumping cutoff water level LWL, the pump 2A The water switching means 3 is closed to cut off the communication between the impeller upstream pipe line 5 and the atmosphere. Then, the valve of the water supply pipe 8 for sealing water
6A is opened, and the blade gap 7A is sealed by the operation of the sealing water source 9. As a result, the self-priming capability of the vertical shaft pump 2A is enhanced and the pumping operation is switched to. That is, only the pump 2A can be pumped.

In addition, when an increase in the amount of inflow water to the pump suction well 1 is predicted, select the number of pumps (for example, all pumps 2A to 2C) that can secure the drainage amount corresponding to the predicted inflow water amount, and select these pumps. Air / water switching means 3 for each of 2A to 2C
Is gradually closed, and in response to this, the valves 6A to 6C of the water supply pipe 8 for sealing water are opened stepwise respectively, so that all of the pumps 2A to 2C are pumped in stages (sequentially). Thus, the water level of the pump suction well 1 can be maintained at the lowest possible level.

That is, while the vertical pump 2A continues the pumping operation, the water level
At the time of rising from 1 to WL2, the vertical shaft pump 2B is also pumped, and while the pumping operation of the compatible shaft pumps 2A and 2B continues, the water level becomes W
When rising from L2 to WL3, 3 vertical shaft pumps 2A-2C
Can be pumped.

Therefore, when the water level of the pump suction well 1 reaches the impeller set water level HWL as in the conventional case, all pumps start pumping operation at the same time to perform drainage, and the total drainage volume of all pumps is greater than the inflow volume. The water level drops significantly to the pumping cutoff level LWL in a short time, and it is possible to switch to air operation again, that is, the operating state is frequently switched between air operation and pumping operation in a short cycle. It is possible to avoid the occurrence of inconvenience that shortens the pump life. Of course, when the state where the amount of water flowing into the pump suction well 1 substantially corresponds to the amount of drainage of one vertical pump is continued, the valve 6A corresponding to the vertical pump 2A is closed and the steam / water switching means 3 is turned on. By opening and switching to air operation, at the same time closing one (2B) steam / water switching means 3 selected from the other pumps 2B, 2C, and controlling the valve 6B to open. Vertical shaft pump
Since the vertical pump 2B can be pumped for the same reason as in the case of 2A, it is possible to prevent the disadvantage that the frequency of use of only the specific pump becomes high and deterioration is accelerated.

In the above embodiment, the impeller clearances of the vertical pumps 2A, 2B, 2C are set.
7a, 7b, 7c and a water source 9 for sealing water are provided through valves 6A, 6B, 6C 1
Although the description has been given with a configuration in which one sealing water supply pipe 8 communicates with each other, as shown in FIG. 3, the blade gap of each pump 2A, 2B, 2C
The present invention also has a configuration in which 4a, 7b, 7c are connected to an independent sealing water source 9 by independent sealing water supply pipes 8 and 6A, 6B, 6C are provided in each sealing water supply pipe 8. Can be carried out, and the same effect as that of the above-mentioned embodiment can be obtained.

Needless to say, the order of pumping the pumps can be arbitrarily selected.

(Effects of the Invention) Since the present invention is configured as described above, it has the effects described below.

That is, according to the first aspect of the present invention, the sealing water is directly supplied from the sealing water source to the blade gap of the vertical pump operating in the air through the sealing supply pipe to seal the blade gap. By this, the self-sufficiency of the vertical shaft pump can be enhanced, and the vertical shaft pump can be pumped up at a water level lower than the installation position of the impeller, thus increasing the water storage effect of the intake well and rapidly When water flows in, it responds appropriately,
It is possible to reliably avoid the inconvenience of overflow from the water intake well. Moreover, by supplying the sealing water directly to the blade gap, the self-priming ability of the pump can be effectively enhanced by supplying only a small amount of the sealing water, and the time until the start of drainage can be shortened very quickly. This has the effect of being able to efficiently switch to a predetermined pumping operation.

Further, according to the second invention of the present application, one of a plurality of vertical shaft pumps operating in the air is selected according to the amount of water flowing into the intake well.
One or more vertical shaft pumps are selected, and the sealing water is directly supplied from the water source for sealing to the blade gaps of the selected vertical pumps through the sealing supply pipe to seal the blade gaps. With this, the self-sufficiency of the vertical shaft pump is enhanced, and the selected vertical shaft pump can be pumped in stages at a water level lower than the installation position of the impeller. It is possible to reliably prevent the occurrence of inconveniences such as shortening of the pump life due to frequent switching to. Moreover, by supplying the sealing water directly to the blade gap, it is possible to effectively enhance the self-sufficiency of the pump by supplying only a small amount of sealing water and shorten the time until the start of drainage, resulting in extremely quick and efficient operation. This has the effect of being able to switch to a predetermined pumping operation well.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing a system example of a vertical shaft pump and a water supply system for sealing water applied to the implementation of the first invention according to the present invention,
FIG. 2 is an explanatory view showing an arrangement of a vertical shaft pump and a system example of a water supply system for sealing water applied to the implementation of the second invention, and FIG. 3 is an explanatory view showing another embodiment of the second invention. is there. 1 …… Pump suction well 2,2A ～ 2C …… Vertical pump 2a ～ 2c, 20 …… Impeller 4 …… Impeller chamber 6,6A ～ 6C …… Valve 7,7a ～ 7c …… Blade gap 8 …… Sealing water supply pipe 9 ... Sealing water source HWL ... Impeller set water level LWL ... Pumping cutoff water level WL1, WL2, WL3 ..

Front page continuation (72) Inventor Hirohiko Furukawa 1-1-1, Nakanomiya Oike, Hirakata City, Osaka Prefecture Kubota Hirakata Factory (72) Inventor Masahide Konishi 1-1-1, Nakamiya Oike, Hirakata City, Osaka Prefecture KUBOTA Hirakata Factory (56) Reference JP-A-2-126000 (JP, A) JP-A-63-189694 (JP, A)

Claims (2)

(57) [Claims] 1. A method of operating a vertical shaft pump, wherein an impeller is arranged above a pumping cutoff water level specific to the pump,
The blade gap formed between the outer circumference of the impeller of the vertical shaft pump and the inner circumference of the impeller is directly communicated with the water source for sealing water by the water supply pipe for sealing water, the water level rises and the water level reaches the impeller. Before starting, the vertical pump is pumped at a water level lower than the installation position of the impeller by supplying the sealing water from the sealing water source through the sealing water supply pipe to the blade gap to seal the blade gap. A method for operating a vertical shaft pump, which is characterized in that 2. A method of operating a plurality of vertical shaft pumps, wherein the impeller is arranged in a water intake well at a level higher than a pumping water cutoff level specific to the pump, and the impeller of each of the plurality of vertical shaft pumps. The blade gap formed between the outer circumference and the inner circumference of the impeller chamber and the water source for sealing water are directly communicated with each other by the water supply pipe for sealing water, and the vertical axis is reached before the water level rises and the water level reaches the impeller. The vertical shaft pump is selected from the pumps by supplying the sealing water from the water source for sealing water through the supply pipe for sealing water to the blade gap of the vertical shaft pump to seal the blade gap. A method for operating a vertical pump, which is characterized in that pumping operation is performed at a water level lower than the installation position.