JPH04143496A - Operating method for vertical shaft pump - Google Patents

Abstract

PURPOSE:To have pumping operation even when the water level in a water sucking well is below the level where an impeller is installed, by putting the inter-vane gap in communication with a water source for sealing through a water supply pipe for sealing, and supplying the water for sealing to the vane gap from the water source before rising water level attains the impeller. CONSTITUTION:The vane gap 7 formed between the periphery of an impeller 20 and the internal circumference of an impeller chamber 4 is in communication with a water source 9 for sealing through a water supply pipe for sealing 8 equipped with a valve 6. In the condition that the water level in a water sucking well 1 is below the pumping breaking level LWL and that a vertical axis pump 2 is in no-load operation, an air-water changeover means 3 is closed when the amount of influx water increases to cause exceeding slightly the pumping breaking level LWL, and the impeller upstream pipeline 5 is shut off from communication to the atmosphere. Then the valve 6 on the water supply pipe 8 for sealing is opened, and the vane gap 7 is water sealed through the action of the water source for sealing 9. As a result, the self-sucking capability of the pump is enhanced, and changing-over is made into pumping operation.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method of operating a vertical shaft pump, and particularly a method of operating a vertical shaft pump performed in a water intake well of a drainage pump station installed in a waterway or rainwater pump equipment. Regarding.

(Prior Art) Water flowing into a water suction well of a drainage pump station is often drained by pumping operation of one or more vertical shaft pumps arranged in the water suction well.

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

In this way, by using the same type of pump and installing all the impellers at the same level, the pumps are compatible with each other, so in the event of deterioration over time or a failure, etc. This makes it easier to manage the replacement parts that need to be replenished. In addition, it is possible to avoid the inconvenience that only a specific pump is used more frequently, and pumping operation time is longer than other pumps, resulting in accelerated deterioration (problem to be solved by the invention). However, in the conventional method described above, Pumping operation cannot be performed unless the water level rises to the impeller level.

In addition, when draining water using multiple spindle pumps, if the water level in the pump suction well rises and reaches the impeller installation level while all pumps are in submerged operation, at this point all The pumps will start pumping operation all at once to drain the water. In this case, if the total amount of water discharged by all pumps is greater than the amount of water flowing into the pump suction well, the water level will drop to the pumping cutoff level in a single hour, and the pump will be switched to submerged operation again. In other words, the operating state is frequently switched between submerged operation and pumping operation in short cycles, which can be a factor in shortening the life of the pump.

The present invention was developed in view of these circumstances, and enables water pumping operation in response to requests for drainage even when the water level in the water intake well is below the level at which the impeller is installed, and also uses multiple shaft pumps. When discharging water, one or more pumps selected according to the amount of water flowing into the water intake well are operated at a water level lower than the impeller installation level, and the life of the pump is increased by frequent switching of operating conditions. The purpose of the present invention is to provide a pump operating method that can avoid a decrease in

(Means for Solving the Problems) In order to achieve the above object, a first invention according to the present invention provides a method of operating a spindle pump in which an impeller is arranged above a pump-specific pump cutoff water level. The blade gap formed between the outer periphery of the impeller of the spindle pump and the periphery of the impeller chamber is communicated with a water sealing water source through a monthly water supply pipe,
Before the water level rises and reaches the impeller, water sealing water is supplied from the water sealing water source to the gap between the blades for pumping operation.

In addition, in order to achieve the above object, a second invention according to the present invention provides a pump water suction system in which a plurality of spindle pumps each having an impeller placed above a pump-specific pumping cut-off water level and arranged at the same level. In a drainage pump station arranged in a well, the blade gaps formed between the outer periphery of the impeller and the periphery of the impeller chamber of each of the plurality of spindle pumps are communicated with a water sealing water source through a water sealing water supply pipe. , Before the water level rises and reaches the impeller, sealing water is supplied from the sealing water source to the blade gap of the spindle pump selected from among all the spindle pumps to perform pumping operation. .

(Function) According to the first invention, sealing water is supplied from the water sealing water source to the blade gap of the spindle pump operating in air, and the blade gap is sealed, thereby causing the pump to self-prime. The capacity is increased, and the spindle pump can be operated in advance at a water level below the impeller installation level.

Further, according to the second invention, one or more spindle pumps are selected from among all the spindle pumps operating in air according to the amount of water flowing into the pump suction well, and By supplying sealing water from a water injection water source to the blade gap of the selected pump and sealing the blade gap, the self-priming capacity of the cylinder is increased, and the selected spindle pump is lowered from the pumping water level. Pumping operation can also be performed in advance at lower water levels.

That is, the pumping start water level of each pump can be set to a different water level, and it is possible to avoid a situation where all pumps start pumping at the same time. Therefore, the operating state is not frequently switched between submerged operation and pumped storage operation.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 11 is an explanatory diagram showing a system example of a spindle pump and a water sealing water supply system applied to the implementation of the first invention, and in the figure, the spindle is placed in the pump suction well l of the drainage pump station. The position of the impeller 20 of the pump 2 is set higher than the pumping cutoff water level (lowest water level) HWL5 of the water intake well 1, and pumping operation is normally possible when the water level reaches the impeller. In addition, the spindle pump 2 operates at a pumping cutoff water level LW where the water level of the water suction well l is lower than the impeller HWL.
When the water level drops to L, an upstream pipe (suction bell mouth) 5 upstream of the impeller 20 is connected via an air/water switching means 3 that is opened in response to a water level detection signal from a water level sensor (not shown).
Atmospheric air is introduced into the reactor, and the resulting vacuum break causes a switch to air operation.

The blade gap 7 formed between the outer periphery of the impeller 20 and the inner periphery of the impeller chamber 4 is connected to a sealing water source (pump) 9 via a sealing water supply pipe 8 in which a valve 6 is installed. It's communicating.

Next, the operation will be explained.

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

FIG. 2 is an explanatory diagram showing an arrangement of a spindle pump and a system example of a water injection water supply system applied to the implementation of the second invention.
In the figure, a plurality of (for example, three) spindle pumps 2A are installed in the pump suction well l of the drainage pump station.

2B and 2C are placed. Impeller 2 of these pumps
The positions of a, 2b, and 2c are set at the same level. That is, the impeller H of each pump 2A, 2B, 2C
WL is unified, and normally the water level is between impellers 2a and 2.
Both pumps are ready for pumping operation when they reach levels b and 2c.

In addition, each pump 2A, 2B, 2C is connected to one blade via an air/water switching means 3 which is opened in response to a water level detection signal from a water level sensor (not shown) when the water level in the water intake well l drops to the pumping cutoff level LWL. Atmospheric air is introduced into the upstream pipe (suction bell mouth) 5 upstream of the cars 2a, 2b, and 2c, and the resulting vacuum breakage causes a switch to air operation.

The outer periphery of the impellers 2a, 2b, and 2c and the impeller chamber 4A.

Blade gaps 7a, 7b formed between 4B and 4C,
7c communicates with a water sealing water source (pump) 9 via a water sealing water supply pipe 8 in which valves 6A, 6B, and 6C are provided.

Next, the operation will be explained.

When the water level of the pump suction well 1 is below the pumping cutoff water level LWL and each of the spindle pumps 2A, 2B, and 2C is operating in the air, a drainage volume approximately equivalent to the amount of water flowing into the pump suction well 1 is secured. Select as many pumps as possible0
For example, if the amount of inflow water approximately corresponds to the displacement of one pump, select pump 2A, and when the water level reaches WLI, which is the same as or slightly higher than the pumping cutoff level LWL, the pump 2A will be discharged. The water switching means 3 is closed to cut off communication between the impeller upstream pipe line 5 and the atmosphere.

Next, the valve 6A of the sealing water supply pipe 8 is opened, and the blade gap 7A is sealed by the operation of the sealing water source 9. As a result,
The self-priming capacity of the spindle pump 2A is increased and the operation is switched to pumping operation. In other words, only the pump 2A can be operated for pumping water.

In addition, if an increase in the amount of water flowing into the pump intake well 1 is predicted, the number of pumps (for example, all pumps 2A to 2C) that can ensure the amount of drainage corresponding to the predicted amount of water flowing in is required.
and close the air/water switching means 3 of each of these pumps 28 to 2C in stages, and correspondingly open the six valves 6A to 6C of the water sealing water supply pipe 8 in stages. This allows all of the pumps 2A to 2C to perform pumping operation in stages (sequentially) to maintain the water level in the pump suction well 1 at the lowest possible level.

That is, during the continuous pumping operation of the spindle pump 2A, the water level is
At the time of rising from LI to WL2, the spindle pump 2B is also brought into pumping operation and the single spindle pump 2A is operated.

When the water level rises from WL2 to WL3 while water pump 2B continues pumping operation, the three spindle pumps 2A to 2C can be brought into pumping operation.

Therefore, as in the past, when the water level in the pump suction well l reaches the pumping start level HWL, all pumps start pumping operation at the same time and drain water, and the total amount of water discharged by all pumps is larger than the amount of inflow water. The problem is that the water level decreases to the pumping cut-off level LWL in a short period of time and the operation is switched to submerged operation again. The occurrence of inconveniences that reduce pump life can be avoided. Of course, if the amount of water flowing into the pump suction well 1 continues to be approximately equivalent to the displacement of one spindle pump, the above-mentioned spindle pump 2A
Closes the valve 6A corresponding to the pump, opens the air-water switching means 3 to switch to air operation, and at the same time switches on one air-water switching means 3 selected from the other pumps 2B and 2C (for example, 2B). By controlling the valve 6B to close and open the valve 6B,
For the same reason as in the case of the spindle pump 2A, the spindle pump 2
Since pump B can be operated in a pumping operation, it is possible to prevent the drawback that only a specific pump is used more frequently and its deterioration is accelerated.

In the above embodiment, the impeller gaps 7a, 7b, 7c of the respective shaft pumps 2A, 2B, 2C and the water sealing water source 9 are connected to the valve 6A.
, 6B, and 6C are connected through a single sealing water supply pipe 8, but as shown in FIG. 3,
Blade gaps 7a, 7 of each pump 2A, 2B, 2C
b, 7c are communicated with independent water sealing water sources 9 through independent water sealing water supply pipes 8, and the present invention can also be implemented with a configuration in which 6A, 6B, and 6C are interposed in each water sealing water supply pipe 8. is possible, and the same effects as in the embodiment described above can be achieved.

Moreover, it goes without saying that the order in which the pumps are operated for pumping water can be arbitrarily selected.

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

That is, according to the operating method of a spindle pump according to claim (1), sealing water is supplied from a water sealing water source to the blade gap of the spindle pump operating in air to seal the blade gap. By pumping water, the self-priming ability of the pump is increased, and the spindle pump can be operated in advance at a water level lower than the impeller installation position. Therefore, the water storage effect of the water suction well increases, and even if a large amount of water suddenly flows in, it is possible to reliably prevent the pump water suction well from overflowing.

Further, according to the method for operating a spindle pump according to claim (2), one or more spindles are selected from among all the spindle pumps operating in the air, depending on the amount of water flowing into the pump suction well. By selecting a pump and supplying sealing water from a sealing water source to the blade gap of the selected pump to seal the blade gap, the self-priming ability of the pump is increased, and the self-priming ability of the pump is increased, and the self-priming ability of the pump is increased by The pump can be operated to pump water in stages at a water level lower than the impeller installation position. Therefore, it is possible to reliably prevent the occurrence of inconveniences such as shortening the life of the pump due to frequent switching of the operating state between submerged operation and pumped water operation.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a system example of a spindle pump and a sealing water supply system applied to the implementation of the first invention according to the present invention,
Fig. 2 is an explanatory diagram showing the arrangement of the spindle pump and a system example of the sealing water supply system applied to the implementation of the second invention, and Fig. 3 is an explanatory diagram showing another embodiment of the second invention. It is. 1... Pump water suction well 2.2A-2C... Support shaft pump 2a-2c, 20... Impeller 4... Impeller chamber 6.6A-6C... Valves 7.7a-7C. ...Blade gap 8...Sealing water supply pipe 9...Sealing water source HWL, WLI, WL2. WL3...impeller LWL
... Pumping water cutoff water level patent applicant Kubota Kaisha Ltd. Patent attorney Takashi Suzue

Claims (2)

[Claims] (1) An operating method for a vertical shaft pump in which the impeller is placed above the pump's own pump-specific water cut-off water level, in which the blade gap formed between the outer periphery of the impeller of the vertical shaft pump and the periphery of the impeller chamber. The water sealing water source is communicated with the water sealing water supply pipe through a water sealing water supply pipe, and before the water level rises and reaches the impeller, water sealing water is supplied from the water sealing water source to the blade gap to perform pumping operation. How to operate a vertical shaft pump. (2) In a drainage pump station where a plurality of vertical shaft pumps are arranged in a pump suction well, the impeller is above the pump-specific pumping cutoff water level and is arranged at the same level, the impeller of each of the plurality of vertical shaft pumps is The blade gap formed between the outer periphery of the car and the periphery of the impeller chamber is communicated with a water sealing water source through a sealing water supply pipe, and before the water level rises and reaches the impeller, water is supplied from all vertical shaft pumps. A method for operating a vertical shaft pump characterized by supplying sealing water from a sealing water source to a selected blade gap of the vertical shaft pump for pumping operation.