JPH04148097A - Method of operating horizontal shaft pump - Google Patents

Abstract

PURPOSE:To prevent the timing of start of water pump-up operation from being delayed, by performing an air-standby operation of a horizontal shaft pump until the water level of a pump-up water well increases from a lowest level LWL to a pump-up start level HWL, and by promptly changing over the operation of the pump into a water pump-up operation from the air-operation when the water level reaches the water pump-level. CONSTITUTION:A pump drive prime-mover 14 is started in a clutch 13 turn-on condition until the water level of a pump-up water well 1 rises from a lowest level LWL to a pump-up start level HWL, and accordingly, a pump falls into a full speed air operation or a full speed standby operation. A vacuum pump 20 in a water level raising means 11 is started in response to a water level detecting signal which is delivered when the water level comes to the pump-up start level HWL, and accordingly, the water level in a suction pipe 4 is raised up to a full water level LWL1 at which a horizontal shaft pump can discharge water by itself alone, and the operation is promptly shifted into the pump-up operation. With this arrangement, even in emergency operation in which a large volume of water abruptly flows into the pump-up water well 1, the timing of start of the pump-up operation is prevented from being delayed, thereby it is possible to surely prevent occurrence of a flood caused by abnormal rise of the water level of the pump-up water well 1.

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 l of the drainage pump station shown in Fig. 2, when the water level in the suction well l 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 inside 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 this state is detected by the full water detector 6, which then detects the full water level. Based on the signal, a pump driving prime mover (for example, a diesel engine), not shown, is started to operate the pump (rotating the impeller 3), and then the discharge valve 7 is fully opened to perform a drainage operation (pumping operation). Driving method is adopted.

[Problems to be Solved by the Invention] However, in the conventional operating method, the pump is operated only after the water level in the water intake well l reaches the pumping start water level HWL. prime mover (
For example, starting a diesel engine takes time. Moreover, even in the unlikely event that a failure occurs in the pump or drive motor, these failures will cause the water level to drop below the pumping starting water level HW.
Since confirmation cannot be made until the drive motor is started after reaching L, there will be a delay in the start timing of pumping operation, and the water intake well L will be delayed.
The water level could rise abnormally, leading to flooding.

In particular, 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 intake well 1 tends to increase, a situation in which a large amount of water suddenly flows into the water intake well 1, such as a so-called flash flood, is likely to occur. There is a need to prevent delays in the start timing of drainage and ensure proper drainage.

The present invention has been made in view of the above circumstances, and it is possible to confirm a failure before a large amount of water suddenly flows into a water absorption well, thereby preventing the occurrence of flooding due to an abnormal rise in the water level of the water absorption well. The purpose is to provide a method of operating a horizontal shaft pump that allows for

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a system in which the horizontal shaft pump is submerged in advance before the water level of the water suction well in which the horizontal shaft pump is installed reaches the pumping start water level. During standby operation, when the water level reaches the pumping start water level, the water level raising means is activated to raise the water level in the pump to a level corresponding to the water level at which the horizontal shaft pump can drain water with its self-priming capacity. It was raised in height for pumping operation.

[Function] According to the present invention, the horizontal shaft pump is operated in aerial standby mode until the water level of the water intake well reaches the pumping start water level from the lowest water level, and when the water level reaches the pumping start water level, By activating the water level raising means, the water level inside the pump can be raised to a height corresponding to the water level that can be drained by the horizontal shaft pump with its self-priming ability, and pumping operation (drainage operation) can be performed. 1. Even if there is a failure in the pump or driving engine, the failure can be confirmed before the water level reaches the pumping start water level.

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

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and the same or corresponding parts as in the conventional example shown in FIG. 2 are given the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, a pump main shaft 12 with an impeller 3 fixed to its tip is connected to an output shaft 14A of a pump driving prime mover (for example, a diesel engine) 14 via a clutch 13, and is located downstream of a discharge valve 7. The outlet of the discharge pipe 8 faces the water of a drainage channel (for example, a river) 9.

The vacuum system 2 includes a vacuum pump 20, an intake pipe 24 that communicates the intake side of the vacuum pump 20 with the impeller 10 in the pump casing 5, and a vacuum pump 20 that is connected to the intake pipe 24 in series from the vacuum pump 20 side. It is composed of a valve 21 and a pressure switch 23, and the vacuum system 2 constitutes a water level raising means 11.

The water level raising means 11 is configured to raise the water level in the suction pipe 4 (the water level in the pump) to a level at which the horizontal axis pump can drain water with its self-priming ability, not only when the discharge valve 7 is fully closed but also when it is fully opened. For example, the discharge pipe that has the function of raising the water level to the full water level HWL 1) of the pump, which faces the water in the drain channel 9 from the water surface in the suction pipe 4 when the discharge valve 7 is fully open, is A series of closed spaces A formed towards the exit of 8.
A vacuum pump 20 that can create a negative pressure in the suction pipe 4 and raise the water level in the suction pipe 4 to the full water level HWLl is the vacuum system 2.
The full water level HWLl is set at pressure switch 2.
The operation of the above-mentioned structure will be explained while maintaining the vacuum pump 20 properly by controlling the operation of the vacuum pump 20 based on the pressure detection signal of No. 3.

■Before the water level of the water intake valve reaches from the lowest water level LWL to the pumping start water level HWL, start the pump drive motor 14 with the clutch 13 ON and operate the pump in full speed air, that is, in full speed standby mode. . In this case, the valve 21 may be left open.

(2) When the water level of the water intake valve reaches the pumping start water level HWL, this water level is detected by a water level detection means (not shown), and the water level raising means 11 is activated based on the water level detection signal of the water level detection means.

That is, the vacuum pump 20 is started.

(2) By the operation of the water level raising means 11 in (2) above, the water level in the suction pipe 4 is raised to the full water level HWL1 at which the horizontal axis pump can drain water with its self-priming ability, and pumping operation (drainage operation) is immediately started. It will be done.

In this way, as soon as the water level in the water intake well 1 reaches the pumping start water level HWL, the pumping operation is started immediately, so even in an emergency when a large amount of water suddenly flows into the water intake well 1, the pumping operation can be started immediately. Since there is no delay in the start timing, flooding caused by an abnormal rise in the water level of the water intake well 1 can be reliably prevented.

In addition, the pump body and the driving force 4I for driving the pump! 114 and the discharge valve 7, etc., the failure can be confirmed and dealt with before the water level of the water intake well 1 reaches the pumping start water level HWL, so in an emergency The reliability of the drainage pump station can be improved.

It is also possible to confirm the failure at an earlier point in time by carrying out the operation (2) above at the lowest water level LWL with no swirl.

In the embodiment, the water level raising means 11 is raised by the vacuum system 2.
Although the present invention is not limited to the above embodiment, the water intake well 1 is configured to be airtight, and the pressure is set based on the pressure detection signal of the pressure switch 23. The water level raising means 11 may be constituted by a compressed air supply system (not shown) that can apply a high pressure to the water surface in the water intake well l, as shown by a plurality of arrows P in Fig. 881.

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

In other words, the horizontal shaft pump is put into submerged standby operation until the water level in the water intake well reaches the pumping start water level from the lowest water level, and when the water level in the water intake well reaches the pumping start water level, it is immediately put into submerged operation. (Full-speed standby operation) to pumping operation (Full-speed draining operation) It is possible to reliably prevent flooding caused by an abnormal rise in the water level in the water intake well, and even if a failure occurs in the pump body or the pump drive motor, the water level in the water intake well can be prevented before the water level reaches the pumping start water level. Since malfunctions can be confirmed and dealt with in advance, proper drainage can be performed in an emergency, and the reliability of the drainage pump station can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of a conventional example. 1...Water intake well 11...Water level raising means HWL...Pumping start water level LWL...Minimum water level HWLI...Water level at which the horizontal shaft pump can drain water with its self-priming capacity (full water level)

Claims (1)

[Claims] (1) Before the water level of the water intake well in which the horizontal shaft pump is installed reaches the pumping start water level, the horizontal shaft pump is placed in a submerged standby operation in advance, and when the water level reaches the pumping start water level, A method for operating a horizontal shaft pump, characterized in that, by operating a water level raising means, the water level in the pump is raised to a level corresponding to the water level at which the horizontal shaft pump can drain water with its self-priming ability, and performs pumping operation.