JP2673741B2 - Operation method of horizontal axis pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for operating a horizontal shaft pump.

[Prior Art] In the conventional suction shaft type horizontal shaft pump installed in the pump suction well 1 of the drainage pump station shown in FIG.
When the water level reaches the pumping start water level HWL, this water level H
WL is detected by the pressure switch 23 of the vacuum system 2 or a water level detecting means (not shown), the vacuum pump 20 is started based on this detection signal, and the inside of the suction pipe 4 arranged upstream of the impeller 3 is detected. Is made to have a high negative pressure, and the water in the suction pipe 4 is sucked up to a level reaching the impeller 3 in the pump casing 5, that is, to the full water level, and this state is detected by the full water detector 6 Based on this, a pump driving motor (not shown) (for example, a diesel engine) is started to operate the pump (rotate the impeller 3).
Is performed, and then the discharge valve 7 is fully opened to perform the drainage operation (pumping operation).

[Problems to be Solved by the Invention] However, in the above-mentioned conventional operation method, it takes time to fully open the discharge valve 7 after the water level of the suction well 1 reaches the pumping start water level HWL. Therefore, the water level is the pumping start water level.
A relatively long waiting time (about 10 minutes) is required before the water is actually drained after reaching the HWL.

On the other hand, in recent years, the water retention function of the stratum has been reduced due to an increase in the pavement rate and a decrease in green spaces due to the progress of urbanization.
In addition, since there is a tendency that the amount of inflow water into the water absorption well 1 is increasing, a situation in which a large amount of water suddenly suddenly flows into the water absorption well 1 like a so-called flash flood easily occurs.

However, in the conventional horizontal axis pump operation method, a relatively long waiting time is required from when the water level of the suction well 1 reaches the pumping start water level HWL to when the pumping operation is started. In an emergency when a large amount of water suddenly flows into the water intake well 1, there may be a delay in the start timing of the pumping operation.

Thus, if the start timing of the pumping operation is delayed,
The water level of the intake well 1 may rise abnormally and cause a flood.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method for operating a horizontal shaft pump that can prevent the occurrence of a flood due to an abnormal rise in the water level of an intake well.

[Means for Solving the Problems] In order to achieve the above object, a method for operating a horizontal shaft pump according to the present invention detects a rise in water level of an intake well in which a horizontal shaft pump is installed by a water level detection means, The water level change rate is calculated based on the detection signal of this water level detection means, and the pumping start water level at which the water level of the suction well reaches the pumping start water level based on the calculated water level change rate and the preset pumping start water level. The arrival time is calculated, and the calculated pumping start water level arrival time is compared with the time required to fully open the discharge valve,
If the time to reach the pumping start water level at the time of calculation is longer than the time required to fully open the pump, the pump starts when the time to reach the pumping start water level, which gradually decreases as the water level in the suction well rises, becomes equal to the time required to fully open. The valve means is activated to control the discharge valve to be fully opened.

Further, in the comparison between the pumping start water level reaching time and the full opening required time, if the pumping start water level reaching time at the time of calculation is shorter than the full opening required time, the discharge valve is immediately and fully opened.

[Operation] According to the present invention, when the water level in the intake well rises,
The rise in the water level is detected by the water level detection means, and the rate of change of the water level is calculated based on the detection signal, and the pumping start water level arrival time is calculated based on the calculated rate of change of the water level and the preset pumping start water level. Then, the calculated pumping start water level reaching time is compared with the time required to fully open the discharge valve by the valve opening means, and if the pumping starting water level reaching time is longer than the full opening required time at that time, , When the pumping start water level reaching time, which gradually decreases as the water level of the intake well rises, becomes equal to the time required for full opening, the valve opening means is activated and the discharge valve is fully opened. Therefore, when the water level of the intake well reaches the pumping start water level, the discharge valve is fully opened. It is possible to prevent the occurrence of water.

In addition, when an abnormal situation occurs where a large amount of water flows into the intake well extremely rapidly, at the time of comparison between the pumping start water level reaching time and the full opening required time, the pumping start water level reaching time is less than the full opening required time. However, in this case, the discharge valve should be immediately fully opened immediately, so that the water level in the suction well may be slightly delayed from the point when it reaches the pumping start water level, but the pumping operation is performed at the earliest possible timing to absorb water. It is possible to prevent the occurrence of floods due to the abnormal rise in the well water level.

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

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention. The same or corresponding parts as those in the conventional example of FIG.

In FIG. 1, a pump main shaft 12 having 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 an opening / closing means 7A composed of, for example, a motor. The outlet of the discharge pipe 8 downstream of the discharge valve 7 that is opened and closed (fully opened or fully closed) by the outlet faces the water in the drainage channel (eg, river) 9.

The vacuum system 2 is provided with a vacuum pump 20, an intake pipe 24 that connects the intake side of the vacuum pump 20 to the impeller inlet 10 of the pump casing 5, and the intake pipe 24 that is connected in series from the vacuum pump 20 side. It is constituted by 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 capable of draining the water level in the suction pipe 4 (water level in the pump) not only when the discharge valve 7 is fully closed but also when the discharge valve 7 is fully opened.
It has the function of raising to L1.

Specifically, when the discharge valve 7 is fully opened, the series of closed spaces A 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 is made negative pressure, and the suction pipe 4 is closed. A vacuum pump 20 capable of suctioning and raising the water level inside to the full water level HWL1 is arranged in the vacuum system 2, and the full water level HWL1 is properly controlled by the operation control of the vacuum pump 20 based on the pressure detection signal of the pressure switch 23. Retained.

The water level of the intake well 1 is detected by the water level detecting means 15,
The detection signal is input to the water level change rate calculation circuit 16, and the calculated water level change rate signal is input to the time calculation circuit 17.

Water level data corresponding to the pumping start water level HWL of the intake well 1 is input to the time calculation circuit 17 in advance. Therefore, the time calculation circuit 17 calculates the time t1 at which the water level of the water intake well 1 reaches the pumping start water level HWL, and the timer circuit 18
The timer circuit 18 outputs the signal to
Is output as a maximum value and the time signal is gradually reduced.

The setting circuit 30 inputs the time t2 required for full opening of the discharge valve 7 to the comparison circuit 19.

The comparison circuit 19 gradually decreases as the water level of the water intake valve 1 increases with the maximum value at the time of calculation of the pumping start water level arrival time t1 calculated based on the water level change rate and the preset pumping start intake HWL. And the time required for full opening t2 of the discharge valve 7 to be compared, and when the pumping start water level reaching time t1 that gradually decreases becomes equal to the time required for full opening t2, the full open signal of the discharge valve 7 Is output. That is, the discharge valve 7
And outputs a valve opening signal to the opening / closing means 7A.

The water level change rate calculation circuit 16, the time calculation circuit 17, the timer circuit 18, the comparison circuit 19 and the setter 30 are one control device.
Built into 31.

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

The water level rise of the water intake well 1 in which the horizontal axis pump is installed is detected by the water level detection means 15, and the water level change rate calculation circuit 16 calculates the water level change rate based on the detection signal of the water level detection means 15.

Based on the calculated water level change rate and the preset pumping start water level HWL, the time calculating circuit 17 calculates the pumping start water level reaching time t1 at which the water level of the water intake well 1 reaches the pumping start water level HWL, and calculates the time. A signal is output from the circuit 17 to the timer circuit 18.

The timer circuit 18 outputs to the comparison circuit 19 a time signal that gradually decreases as the water level of the intake well 1 increases, with the value at the time of calculation of the pumping start water level arrival time t1 calculated as described above as the maximum value. The comparison circuit 19 compares the time t2 required for full opening of the discharge valve 7 input from the setting device 30 with the above-mentioned time signal input from the timer circuit 18,
The valve opening means 7A is activated at the time when the pumping start water level reaching time t1 that gradually decreases becomes equal to the full opening required time t2.

On the other hand, when the water level of the water intake well 1 reaches the pumping start water level HWL, the water level raising means 11 is operated in advance so that the water level in the suction pipe 4 is raised to the full water level HWL1. That is, the inside of the pump is raised to the full water level HWL1.

As a result, when the water level of the intake well 1 reaches the pumping start water level HWL, the pump driving prime mover 14 causes the pump spindle 12
And the drainage is started by rotationally driving the impeller 3. That is, when the water level of the suction well 1 reaches the pumping start water level HWL, the pumping operation (draining operation) is immediately performed.

Of course, before the water level of the suction well 1 reaches the pumping start water level HWL, the pump driving prime mover 14 may rotate the pump main shaft 12 and the impeller 3 to perform an air standby operation.
Before the water level of the water intake well 1 reaches the pumping start water level HWL, only the pump driving prime mover 14 is put into standby operation,
When the water level reaches the pumping start water level HWL, turn the clutch 13 O
Alternatively, the pump main shaft 12 and the impeller 3 may be rotationally driven.

In this way, the pumping operation is performed immediately when the water level of the suction well 1 reaches the pumping start water level HWL. Therefore, even in an emergency when a large amount of water suddenly flows into the suction well 1, the pumping operation is performed. Since there is no delay in the start timing of, the occurrence of flood due to an abnormal rise in the water level of the water intake well 1 can be reliably prevented.

On the other hand, if an abnormal situation occurs in which a large amount of water flows into the water intake well 1 extremely rapidly, at the time of calculating the pumping start water level reaching time t1, the discharge valve 7 is fully opened for a predetermined time t2 rather than the time t1. May be shorter, and in this case, the emergency start signal S is immediately output from the comparison circuit 19 to the opening / closing means 7A, and the water level of the intake well 1 is the pumping start water level HW.
Water intake well 1
It is possible to carry out pumping operation at a timing before the water level of the river rises abnormally so as to lead to flooding.

[Advantages of the Invention] Since the present invention is configured as described above, it has the effects described below.

In other words, the pumping operation (drainage operation) can be performed immediately when the water level of the intake well reaches the pumping start water level, so even in an emergency when a large amount of water suddenly flows into the intake well There is no delay in the start timing of. Therefore, it is possible to reliably prevent the occurrence of flooding due to an abnormal rise in the water level in the intake well, and even if an abnormal situation occurs where a large amount of water flows into the intake well very rapidly, from the time when the water level reaches the pumping start water level. Since the pumping operation can be performed at a slightly delayed timing, it is possible to prevent the occurrence of flooding due to an abnormal rise in the water level of the intake well, enable proper drainage in an emergency, and improve the reliability of the drainage pump station. .

[Brief description of the 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 …… Suction well 7 …… Discharge valve 7A …… Discharge valve opening / closing means 15 …… Water level detection means HWL …… Water pumping start water level

Claims (2)

(57) [Claims] 1. A water level rise in an intake well in which a horizontal axis pump is installed is detected by a water level detection means, and a water level change rate is calculated based on a detection signal of this water level detection means, and the calculated water level change rate. Based on the pumping start water level set in advance, the pumping start water level arrival time at which the water level of the suction well reaches the pumping start water level is calculated, and the calculated pumping start water level arrival time and the time required to fully open the discharge valve are calculated. In comparison, if the pumping start water level arrival time at the time of calculation is longer than the full opening required time, the pumping start water level reaching time that gradually decreases as the water level of the intake well rises becomes the same as the full opening required time. A method for operating a horizontal axis pump, characterized in that the valve opening means is activated at that time to control the discharge valve to be fully opened. 2. The discharge valve is immediately and fully opened when the pumping start water level reaching time and the full opening required time are compared with each other when the pumping start water level reaching time at the time of calculation is shorter than the full opening required time. 1) The method for operating the horizontal shaft pump described above.