JPH04116292A - Operating method for horizontal shaft pump - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a flood due to an abnormal rise of the water level by raising the water level in an intake pipe upstream an impeller than the water level of a water intake well via the action of a water level raising means, and opening a pump discharge valve for the air operation. CONSTITUTION:A vacuum pump IWL setting the sealed space 12 to the negative pressure when a discharge valve 7 is fully opened and sucking and lifting the water level IWL in an intake pipe 4 than the water level of a water intake well 1 by H2 is arranged on a vacuum system 2, and the raised quantity H2 of the water level IWL is properly maintained by the operation control of the vacuum pump 20 based on the pressure detection signal of a pressure switch 23. When the water level of the water intake well 1 reaches the pumping start water level HWL, the water level in the intake pipe 4 is raised to the level higher than it by H2, i.e., the water level that the horizontal shaft pump can drain water via the self-suction capability. When the water level of the water intake well 1 reaches the pumping start water level HWL, the air operation is immediately switched to the pumping operation.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of operating a horizontal shaft pump.

[Prior Art] Conventionally, in the suction type horizontal shaft pump installed in the pump suction well 1 of the drainage pump station shown in Fig. 4, when the water level in the suction well 1 reaches the pumping start water level HWL, This water level HWL is detected by the pressure switch 23 of the vacuum system 2 or a water level detection means (not shown), and the vacuum pump 20 is started based on this detection signal, and the suction pipe 4 disposed upstream of the impeller 3 The water in the suction pipe 4 is sucked up to the level that reaches the impeller 3 in the pump casing 5, that is, the full water level, and after this state is detected by the full water detector 6, a full water detection signal is generated. The pump is operated (the impeller 3 is rotated) based on the discharge valve 7.
An operating method is adopted in which the pump is fully opened for drainage operation (pumping operation).

[Problems to be Solved by the Invention] However, in the conventional operating method, after the water level in the water suction well 1 reaches the pumping start water level HWL, the vacuum pump 20 is started to create a high negative pressure inside the suction pipe 4. It takes time to fill the inside of the pump casing 5 with water, and since the discharge valve 7 is fully opened after the pump is started, it takes time for the water to actually drain. It takes a relatively long time (approximately 10 minutes) from the time the water reaches the water to the start of the drainage operation.

On the other hand, in recent years, the water retention function of geological formations has been declining due to an increase in paving ratio and a decrease in green areas due to the progress of urbanization. Moreover, since the amount of water flowing into the water absorption well 1 tends to increase, a situation in which a large amount of water suddenly flows into the water absorption well 1, such as a so-called flash flood, is likely to occur.

However, in the conventional horizontal shaft pump operation method, a relatively long time is required between the water level in the water intake well 1 reaching the pumping start water level HWL and the pumping operation starting. In an emergency when water suddenly flows into the water intake well l, there may be a delay in the start timing of the pumping operation.

As described above, if the start timing of the pumping operation is delayed, the water level in the water intake well 1 may rise abnormally, leading to a flood.

In addition, even if a failure occurs in the pump body, drive system, vacuum system 2, discharge valve 7, etc., a predetermined period of time will elapse after the water level in the suction well l reaches the pumping start water level HWL and water pumping (drainage) is required. The above-mentioned failure cannot be confirmed until the period has passed, and therefore, it may not be possible to properly drain the water in an emergency.

The present invention was developed in view of the above circumstances, and by operating at full speed regardless of the water level of the water intake well, it is possible to perform standby operation that can cope with sudden increases in water level, and to prevent abnormal rises in water level. The object of the present invention is to provide a method of operating a horizontal shaft pump that can prevent the occurrence of flooding and also prevent the occurrence of pump operation malfunctions due to an abnormal drop in water level.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the first invention according to the present invention provides a water suction well in which a horizontal shaft pump is installed, from the lowest water level to just before reaching the pumping start water level. During this period, the water level in the suction pipe upstream of the impeller is raised by the operation of the water level raising means to a height corresponding to the height from the pumping start water level to the water level at which the horizontal axis pump can drain water with its self-priming capacity, above the water level in the water suction well. With,
The pump discharge valve is opened to perform submerged operation, and pumping operation is automatically started when the water level in the water intake well reaches the pumping start water level.

Further, in the second aspect of the present invention, the water level in the suction pipe upstream of the impeller is activated by the operation of the water level raising means until the water suction well in which the horizontal shaft pump is installed reaches the pumping start water level from the lowest water level. The water level is raised above the water level in the suction well by an amount corresponding to the height from the pumping start water level to the water level at which the horizontal shaft pump can drain water with its self-priming capacity, and the pump discharge valve is opened to perform submerged operation. Pumping operation is automatically started when the water level in the water intake well reaches the pumping start water level, and when the water intake well drops below the minimum water level, air is introduced into the impeller inlet by opening the pumping cutoff means and the system switches to air operation. This is what I did.

[Operation] According to the first aspect of the present invention, immediately before the water level of the water suction well reaches the pumping start water level from the lowest water level, the water level in the suction pipe upstream of the impeller is raised by the operation of the water level raising means. The water level in the water suction well is raised to a level corresponding to the height from the pumping start water level to the water level at which the horizontal shaft pump can drain water with its self-priming capacity, and the pump discharge valve is opened to perform full-speed standby operation.

In this state, when the water level in the water intake well reaches the pumping start water level,
The water level in the suction pipe is raised by the water level raising means to a level at which the horizontal shaft pump can drain water with its self-priming ability.

Therefore, at this point, it is possible to automatically switch to pumping operation. In other words, when the water level in the water intake well reaches the pumping start water level, it is possible to immediately switch from submerged operation to pumping operation.

According to the second aspect of the present invention, the water level in the suction pipe upstream of the impeller is raised by the operation of the water level raising means until the water level in the water suction well reaches the pumping start water level from the lowest water level. The water level is increased from the pumping start water level to the water level at which the horizontal axis pump can drain water with its self-priming capacity, and the pump discharge valve is opened to perform full-speed standby operation.

In this state, when the water level in the water intake well reaches the pumping start water level,
The water level in the suction pipe is raised by the water level raising means to a level at which the horizontal shaft pump can drain water with its self-priming ability.

Therefore, at this point, it is possible to automatically switch to pumping operation. In other words, when the water level in the water intake well reaches the pumping start water level, it is possible to immediately switch from submerged operation to pumping operation.

Then, when the water level in the water intake well falls below the lowest water level due to the pumping operation, the pumping cutoff means is opened. As a result, air is introduced into the impeller inlet and the operation can be switched to air operation.

[Example] An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a schematic configuration diagram of the first embodiment, and the same or equivalent parts as in the conventional example shown in FIG. 4 are denoted by the same reference numerals.
A detailed explanation thereof will be omitted.

In FIG. 1, the outlet of the discharge pipe 8 downstream of the discharge valve 7 faces the water of a drainage channel (for example, a river) 9. The vacuum system 2 includes a vacuum pump 20 and the suction side of this vacuum pump 20. It is composed of an intake pipe 24 that communicates with the impeller inlet 10 of the pump casing 5, and a valve 21 and a pressure switch 23 that are connected in series to this intake air v24 from the vacuum pump 20 side. It constitutes a lifting means 11.

The water level raising means 11 has a function of raising the water level IWL in the suction pipe 4 by H2 above the water level in the suction well 1 when the discharge valve 7 is fully opened. The water level IWL in the suction pipe 4 can be raised to correspond to the height H2 up to the water level at which the axial pump can drain water with its self-priming ability.

Specifically, when the discharge valve 7 is fully opened, a series of sealed spaces 12 formed from the water surface in the suction pipe 4 to the outlet of the discharge pipe 8 facing the water in the drainage channel 9 are made negative pressure, and the suction pipe 4 is A vacuum pump 20 capable of suctioning and raising the water level IWL in the suction well l by an amount H2 above the water level in the water suction well l is disposed in the vacuum system 2. The vacuum pump 20 is properly maintained by controlling the operation of the vacuum pump 20 based on the above.

Next, the operation of the above configuration will be explained.

(2) When the water level of the water intake well l reaches the lowest ice level LWL from below the lowest water level LWL, this water level LWL is detected by a water level detection means (not shown), and the vacuum pump 20 is activated based on the water level detection signal of the water level detection means. and valve 21.
Open the valve. In other words, the water level raising means 11 is activated.

At the same time, based on the water level detection signal, the discharge valve 7 is fully opened and the pump is started to perform full-speed atmospheric operation, that is, full-speed standby operation.

(2) By the operation of the water level raising means 11 in (2) above, the water level IWL in the suction pipe 4 is raised by H2 above the water level LWL in the water intake well 1 (see Figure 2A). Immediately before reaching the start water level HWL, full-speed standby operation is performed with the water level IWL in the suction ee4 raised by the operation of the water level raising means 11 to a level corresponding to H2 higher than the water level in the water suction well 1. .

■When the water level in the suction well l reaches the pumping start water level HWL, the water level in the suction pipe l is at a level H2 higher than this level,
In other words, the water level of the horizontal shaft pump is raised to the level at which water can be drained with its self-priming capacity (see Figure 2B).
When the water level reaches the pumping start water level HWL, the submerged operation is immediately switched to the pumping operation.

In this way, when the water level in the water intake well 1 reaches the pumping start water level HWL, the operation is immediately switched from submerged operation to pumping operation, so even in an emergency when a large amount of water suddenly flows into the water intake well 1, Since there is no delay in the start timing of the pumping operation, it is possible to reliably prevent flooding due to an abnormal rise in the water level of the water intake well 1.

In addition, even if a failure occurs in the pump body, drive system, vacuum system 2, discharge valve 7, etc., the failure can be confirmed and corrected when the water level in the water intake well 1 reaches the lowest water level LWL. This enables proper drainage in emergencies and improves the reliability of the drainage pump station.To confirm the above-mentioned failure, perform the operation in (①) above at the lowest water level LWL with no vortex. It is also possible to do this at an earlier point in time.

FIG. 3 is a schematic configuration diagram of the second embodiment. In this embodiment, the lower open end is set at the same level as the lowest water level LWL of the water intake well 1, and the upper open end is opened to the impeller inlet 10. A water pumping cutoff means 13 consisting of a pipe is attached.

With such a configuration, the water level of water absorption well L is the lowest water level L
When rising from the lower level of WL, the operation is performed in the same manner as in the above-mentioned ■ to ■, and the water level of the water intake well l is brought up to the pumping start water level HWL by the It1 sequence of pumping operation.
Pumping operation is also performed while the water level is lowering from a higher water level to the lowest water level LWL.

Then, when the water level of the water intake well 1 falls below the lowest water level LWL and the submerged state of the lower open end of the water pumping cutoff means 13 is released, air is introduced into the impeller inlet 10 from here. The system is switched to full-speed atmospheric operation (full-speed standby operation) with water pumping cut off. Therefore, without stopping the pump, it is also possible to reliably prevent the occurrence of pump operation malfunction due to vortex suction due to an abnormal drop in the water level of the water intake well I.

In each of the above embodiments, the water level raising means 1 is
1 has been described, the present invention is not limited only to the above-mentioned embodiment, but the present invention is not limited to the above-mentioned embodiment. The water level raising means 11 is constituted by a compressed air supply system (not shown) that can apply a high pressure of a value to the water surface in the water absorption well 1, as shown by a plurality of arrows P in FIGS. 1 and 3. You may.

In addition, in the second embodiment, the pumping cutoff means 1 is constructed by a pipe whose lower open end is set at the same level as the lowest water level LWL of the water intake well l, and whose upper open end is opened to the impeller inlet lO.
3, this pumping cutoff means 13 is not limited to the embodiment, but may also include a valve (not shown) that penetrates the pump casing 5 and communicates or cuts off the impeller inlet 10 with the atmosphere. ), and the opening and closing of this valve may be controlled based on, for example, a water level detection signal from a water level detection means (not shown).

[Effects of the Invention] Since the present invention is configured as described above, it produces the following effects.

That is, according to the operating method of the horizontal shaft pump according to claim (1), when the water intake well water level reaches the pumping start water level, the pumping operation (full speed drainage operation) is immediately changed from the submerged operation (full speed standby operation) to the pumping operation (full speed drain operation). ), even in an emergency when a large amount of water suddenly flows into the water intake well, there will be no delay in the start of pumping operation, ensuring that flooding will not occur due to an abnormal rise in the water level in the water intake well. In addition, even if a failure occurs in the pump body, drive system, vacuum system, or discharge valve, the failure can be detected and corrected before the water level in the suction well reaches the pumping start water level. Since it is possible to deal with this problem, proper drainage can be used in an emergency, and the reliability of the drainage pump station can be improved.

Further, according to the method of operating the horizontal shaft pump according to claim (2), when the water intake well water level reaches the pumping start water level, the pumping operation (full speed drainage operation) is immediately changed from the submerged operation (full speed standby operation) to the pumping operation (full speed drainage operation). ), even in an emergency when a large amount of water suddenly flows into the water intake well, there will be no delay in the start of pumping operation, ensuring that flooding will not occur due to an abnormal rise in the water level in the water intake well. In addition, even if a failure occurs in the pump body, drive system, vacuum system, or discharge valve, the failure can be detected and corrected before the water level in the suction well reaches the pumping start water level. Since the problem can be dealt with properly, proper drainage can be performed in an emergency, and the reliability of the drainage pump station can be improved.

Furthermore, when the water level in the suction well drops below the lowest water level, the pumping cutoff means can switch to submerged operation, thereby reliably preventing the occurrence of pump operation malfunctions due to an abnormal drop in the water level in the suction well. becomes possible.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the first embodiment according to the present invention, and FIG.
2B and 2B are explanatory diagrams showing the relationship between the water level in the suction well and the water level in the suction pipe, FIG. 3 is a schematic diagram of the second embodiment of the present invention, and FIG. 4 is a schematic diagram of the conventional example. It is. l...Suction well 3...Impeller 4...Suction pipe 7...Discharge valve 10...Impeller inlet 11...Water level raising means 13...Pumping cutoff means HWL... Pumping start water level LWL...Minimum water level IWL...Water level in the suction pipe H2...Height from the pumping start water level to the water level at which the horizontal axis pump can drain water with its self-priming capacity (amount of elevation)

Claims (2)

[Claims] (1) From the lowest water level to just before the water suction well where the horizontal shaft pump is installed reaches the pumping start water level, the water level raising means is operated to raise the water level in the suction pipe upstream of the impeller to be higher than the water level in the water suction well. The water level is raised from the pumping start water level to the water level at which the horizontal shaft pump can drain water with its self-priming capacity, and the pump discharge valve is opened for air operation, so that the water level in the suction well reaches the pumping start water level. A method of operating a horizontal shaft pump, which is characterized in that it automatically starts pumping operation when the pump reaches the point where the water reaches the pump. (2) From the lowest water level to just before the water intake well where the horizontal shaft pump is installed reaches the pumping start water level, the water level raising means is operated to raise the water level in the suction pipe upstream of the impeller to be higher than the water level in the water intake well. The water level is raised from the pumping start water level to the water level at which the horizontal shaft pump can drain water with its self-priming capacity, and the pump discharge valve is opened for air operation, so that the water level in the suction well reaches the pumping start water level. The horizontal shaft is characterized in that pumping operation is automatically performed when the water level reaches the minimum water level, and when the water level of the water intake well falls below the minimum water level, air is introduced into the impeller inlet by opening the pumping cutoff means and switching to air operation is performed. How to operate the pump.