JP2003139085A - Vertical shaft pump having standby operation function and operation method of vertical pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance water storage capacity of water flowing in a suction well after lowering a water level of the suction well up to a lower level than a pumping cutoff water level by performing pumping operation by a sub-pump by driving the sub-pump by a pump main shaft in parallel to pumping cutoff operation after cutting off pumping. SOLUTION: When the water level of the suction well 10 lowers to the pumping cutoff water level SWL, a steam switching system 6 is switched to an atmosphere opening state, and the pumping cutoff operation is performed by cutting off the pumping by an impeller 2. The pumping operation by the sub-pump 9 is performed by driving the sub-pump 9 by the pump main shaft 1 in parallel to this pumping cutoff operation, and the water level of the suction well 10 is lowered up to the lowest water level LWL lower than the pumping cutoff water level SWL.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical shaft pump having a standby operation function and a method of operating the vertical shaft pump. More specifically, the water level of an intake well in which the vertical shaft pump is installed is lower than the pumping cutoff water level. The present invention relates to a vertical shaft pump and a method of operating the vertical shaft pump, which are lowered to a level and then increase the water storage capacity of water that flows into an intake well.

[0002]

2. Description of the Related Art Conventionally, as a vertical shaft pump having a standby operation function, for example, one shown in FIG. 4 has been known. In this vertical shaft pump, an impeller 2 fixed to a lower end portion of a pump main shaft 1 is rotatably accommodated in a discharge casing 3, a discharge pipe 3 is connected to a discharge side of the discharge casing 3, and a suction side of the discharge casing 3 is suctioned. A state in which the bell 5 is connected, and the suction bell 5 is attached with a steam / water switching system 6 including an atmosphere open steam / water switching pipe 6B provided with a steam / water switching valve 6A so as to communicate with the inlet of the impeller 2. It is installed in the suction well 10. Then, the water intake well 1 detected by the water level detection means 7
The air / water switching valve 6A is configured to be opened / closed by a signal output from the controller 8 based on a water level signal of 0, and the pump main shaft 1 penetrates the discharge curved pipe 11 in a watertight and rotatably manner. It is led out to the outside, connected to a prime mover (not shown), and driven to rotate. A prime mover (not shown) is operated or stopped based on an operation control signal output from the controller 8.

An operation example of the vertical shaft pump having the standby operation function thus configured will be described. When the water level of the suction well 10 rises. A-. Until the water level exceeds the pumping cutoff water level SWL and reaches the pumping start water level RWL, the water / water switching valve 6A is opened to perform pumping cutoff operation in which pumping is blocked. A-. When the water level reaches the pumping start water level RWL, the steam switching valve 6A is closed to switch to the normal drainage operation (100% Q) with a predetermined discharge amount, and the water level above the pumping start water level RWL is the regular drainage operation. I do. When the water level of the suction well 10 drops. B-. From the area where the water level exceeds the pumping start water level RWL,
Regular drainage operation is performed until the pumping start water level RWL is passed and the pumping cutoff water level SWL is lowered. B-. When the water level drops to the pumping cutoff water level SWL, the steam switching valve 6A is opened to switch to pumping cutoff operation in which pumping is cut off, and when the water level is below the pumping cutoff water level SWL, the pumping cutoff operation is continued and the subsequent water level Prepare for the rise.

[0004]

By the way, in the conventional vertical shaft pump, the lowest water level of the suction well 10 is the pumping cutoff water level SW.
It is set to the same level as L and the minimum water level is the pumping cutoff water level S
After lowering it to a level lower than WL, then the water intake well 10
It was not possible to increase the storage capacity of the water flowing into the.

Therefore, according to the present invention, the auxiliary pump is driven by the pump main shaft in parallel with the pumping cutoff operation after the pumping cutoff, and the pumping operation is performed by the subpump so that the water level of the intake well is higher than the pumping cutoff water level. An object of the present invention is to provide a vertical shaft pump having a standby operation function that can reduce the water level to a low level and then increase the water storage capacity of the water that flows into the intake well, and a method of operating the vertical shaft pump.

[0006]

In order to achieve the above object, a vertical shaft pump having a standby operation function according to the invention of claim 1 is a discharge in which an impeller fixed to a pump main shaft is rotatably accommodated. A casing, a suction bell continuously provided on the upstream side of the discharge casing, a pumping pipe continuously provided on the downstream side of the discharge casing, and a communication connected to the inlet of the impeller so that the inside is open to the atmosphere. In a vertical shaft pump having a standby operation function, which includes a steam switching system that is switched to an atmosphere cutoff state, the vane in which the water level is lowered to the pumping cutoff water level and the steam switching system is switched to the atmosphere open state. It is characterized in that it is provided with a sub-pump that is driven by the pump main shaft to perform a pumping operation even during a pumping-off operation in which pumping is stopped by a vehicle.

According to a second aspect of the present invention, there is provided a method for operating a vertical shaft pump having a standby operation function, which includes a discharge casing in which an impeller fixed to a pump main shaft is rotatably accommodated, and an upstream side of the discharge casing. Side connected to the suction casing, a pumping pipe connected to the downstream side of the discharge casing, and an inlet part of the impeller, which are connected in communication with each other to switch the inside into an atmosphere open state and an atmosphere shut off state. With a vertical pump with a standby operation function equipped with a switching system,
When the water level drops to the pumping cutoff water level, the pumping spindle is operated in parallel with this pumping cutoff operation by switching the steam switching system to the atmosphere open state to cut off pumping by the impeller. Drive the auxiliary pump by
It is characterized in that the pumping operation is performed by the auxiliary pump.

According to the first or second aspect of the invention, the water level is lowered to the pumping cutoff water level, the steam switching system is switched to the atmosphere open state, and pumping by the impeller is blocked. Even during the pumping cutoff operation, the pumping operation is performed by the auxiliary pump driven by the pump main shaft, and the minimum water level can be lowered to a level lower than the pumping cutoff water level.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same or corresponding parts as those of the conventional example of FIG. 1 and 2, the pump main shaft 1 extends below the fixed portion of the impeller 2, and an auxiliary pump 9 is drivably connected to the extended end portion thereof.

The sub-pump 9 rotatably accommodates the sub-pump impeller 91 fixed to the sub-pump shaft 90, and is attached to a suction casing 92 having a lower end opened, and immediately below the upper end closed portion of the suction casing 92. The speed increasing device 93 that accelerates the rotation of the pump main shaft 1 and transmits it to the sub pump shaft 90, and the sub pumping pipe 94 whose inlet faces the inside of the suction casing 92 at the upper side (discharging side) of the sub pump impeller 91. And the suction casing 92 has a plurality of guide vanes 12,
It is fixed inside the suction bell 5 via 12, and the position of the lower end opening 92A thereof is set to extend below the position of the lower end opening 5A of the suction bell 5. In addition, sub pumping pipe 9
The passage sectional area of 4 is set to be considerably smaller than the passage sectional area of the pumping pipe 4. The outlet of the sub-water pumping pipe 94 faces a drainage area (not shown).

The operation of the vertical shaft pump having the standby operation function thus configured will be described. When the water level of the suction well 10 rises. A-. Until the water level exceeds the pumping cutoff water level SWL and reaches the pumping start water level RWL, the water / water switching valve 6A is opened to perform the pumping cutoff operation in which the pumping by the impeller 2 is blocked. In this case, since the auxiliary pump 9 is driven by the pump main shaft 1 and is operated in a state of being accelerated by the speed increasing device 93, water is also pumped (drained) from the auxiliary pumping pipe 94 having a small passage sectional area. There is. A-. At the time when the water level of the suction well 10 rises to the pumping start water level RWL, the water / water switching valve 6A is closed, and the normal drainage operation (100% Q) is performed by the cooperation of the drainage by the impeller 2 and the drainage by the auxiliary pump 9. The normal drainage operation is performed at a water level above the pumping start water level RWL.

When the water level of the suction well 10 is lowered. B-. From the area where the water level exceeds the pumping start water level RWL,
The regular drainage operation described above is performed until the pumping start water level RWL is reached and the pumping cutoff water level SWL is lowered. B-. When the water level drops to the pumping cutoff water level SWL, the steam switching valve 6A is opened to switch to the pumping cutoff operation in which the pumping by the impeller 2 is blocked. Even if the pumping cutoff operation is switched to, the auxiliary pump 9 is driven by the pump main shaft 1,
Moreover, since the operation is performed in a state in which the speed is increased by the speed increasing device 93, the drainage from the auxiliary pumping pipe 94 having a small passage cross-sectional area is continued. B-. If the water level is lowered to the minimum water level LWL by continuing the operation of the auxiliary pump 9, this minimum water level LWL is detected by the water level detection means 7, and based on the detected minimum water level signal, the controller 8 causes a motor (not shown) to operate. A stop signal is output to stop the operation of the impeller 2 and the auxiliary pump 9.

In this way, the water level of the water intake well 10 is lowered to the pumping cutoff water level SWL, the steam switching system 6 is switched to the atmosphere open state, and the pumping cutoff operation after the pumping by the impeller 2 is cut off. Even at this time, the sub pump 9 driven by the pump main shaft 1 can perform a pumping operation to lower the water level to the lowest water level LWL lower by ΔH than the pumping cutoff water level SWL, so that the water flows into the suction well 10 next. The water storage capacity can be increased corresponding to the water level difference ΔH.

Next, another embodiment of the present invention will be described. The same or corresponding parts as those of the embodiment shown in FIGS. 1 and 2 and the conventional example of FIG. 4 are designated by the same reference numerals, and the duplicated description of the structure is omitted. In FIG. 3, a sub pump 9 having a sub pump impeller (not shown) is installed in the vicinity of the discharge curved pipe 11 via a bracket 13,
The input shaft 95 is connected to the pump main shaft 1 via a power transmission unit 96 having a speed increasing function, which is formed by a gear train, for example, and is rotationally driven. An auxiliary pumping pipe 94 is attached to the inlet of the auxiliary pump 9, and an inlet of a drain pipe 97 is attached to the outlet of the auxiliary pump 9.
The outlet of the drainage pipe 97 faces a drainage area (not shown).

Even in the vertical pump constructed as described above, the water level of the suction well 10 drops to the pumping cutoff water level SWL, the steam switching system 6 is switched to the atmosphere open state, and the pumping by the impeller 2 is performed. Even during pumping cutoff operation after the
The pumping operation is performed by the auxiliary pump 9 driven by the pump main shaft 1 so that the water level is ΔH higher than the pumping cutoff water level SWL.
Since the minimum water level LWL can be lowered as much as possible, the water storage capacity of the water that subsequently flows into the water intake well 10 can be increased corresponding to the water level difference ΔH.

In the first embodiment, the rotation of the pump main shaft 1 is accelerated by the speed increasing device 93 and transmitted to the auxiliary pump shaft 90. However, the speed increasing device 93 is not always necessary.
The auxiliary pump shaft 90 may be rotated at the same speed as the pump main shaft 1. However, by accelerating and rotating the sub pump shaft 90, the number of rotations of the sub pump impeller 91, which is smaller than the impeller 2, can be increased, and the pumping amount (drainage amount) by the sub pump 9 can be increased. Further, in the second embodiment, the rotation of the pump main shaft 1 is transmitted to the input shaft 95 after being accelerated by the power transmission means 96 having a speed increasing function.
It is not always necessary for 6 to have a speed-up function,
The input shaft 95 may be rotated at the same speed as the pump main shaft 1.
However, by accelerating and rotating the input shaft 95, it is possible to increase the number of rotations of a sub pump impeller (not shown) and increase the pumping amount (drainage amount) by the sub pump 9.

Further, the sub-pump 9 is configured to be operated in parallel with the pumping operation by the impeller 2 in the description.
Between the pump main shaft 1 and the speed increasing device 93 or the power transmission means 9
A clutch is provided between 6 and the input shaft 95, and the clutch is turned on only during the pumping interruption operation after the pumping interruption, the sub-pump 9 is operated by the pump main shaft 1, and the pumping operation by the impeller 2 is performed. Turn off the clutch to turn off the auxiliary pump 9.
The operation may be stopped.

Further, the operation of the auxiliary pump 9 after the pumping off is detected by the water level detecting means 7 to detect the state where the water level is lowered to the minimum water level LWL, and the controller 8 does not show it based on the detected minimum water level signal. A method of outputting a stop signal to the prime mover and controlling so as to stop the operation of the pump main shaft 1 and the auxiliary pump 9 has been described. However, the timer is activated at the same time as switching to pumping cutoff operation in which pumping is cut off, A method may be used in which a stop signal is output to the prime mover after a preset time elapses, and the operation of the pump main shaft 1 and the auxiliary pump 9 is stopped.

[0019]

As described above, since the inventions according to claims 1 and 2 are configured, the following special effects are exhibited.

That is, the pump main shaft is driven even during the pumping interruption operation after the water level is lowered to the pumping cutoff water level, the steam switching system is switched to the atmosphere open state, and the pumping by the impeller is blocked. Since the pumping operation can be performed by the auxiliary pump and the water level can be lowered to the lowest water level lower than the pumping cutoff water level, the storage capacity of the water flowing into the intake well next is the water level lower than the pumping cutoff water level. The difference can be raised correspondingly.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of FIG.

FIG. 3 is a front view showing another embodiment of the present invention.

FIG. 4 is a front view showing an example of a conventional vertical shaft pump having a standby operation function.

[Explanation of symbols]

1 spindle 2 impeller 3 Discharge casing 4 Pumping pipe 5 suction bell 6 steam switching system 9 Sub pump SWL pumping cutoff water level

Claims (2)

[Claims] 1. A discharge casing in which an impeller fixed to a pump main shaft is rotatably accommodated, a suction bell continuous with an upstream side of the discharge casing, and a downstream side of the discharge casing. In a vertical pump having a standby operation function, which has a pumping pipe and a steam switching system that is connected to the inlet of the impeller and is switched between the atmosphere open state and the atmosphere shutoff state, A sub-pump that is driven by the pump main shaft to perform a pumping operation even during a pumping-off operation in which the pumping water is shut down by the impeller whose air-water switching system has been switched to the atmosphere open state by shutting down the water level Vertical shaft pump with a standby operation function. 2. A discharge casing in which an impeller fixed to a pump main shaft is rotatably accommodated, a suction bell continuously connected to an upstream side of the discharge casing, and a downstream side of the discharge casing. The water level is pumped up by a vertical pump having a standby operation function, which includes a pumping pipe and a steam switching system that is connected to the inlet of the impeller and is switched between the atmosphere open state and the atmosphere shutoff state. When the cutoff water level is lowered, the water / water switching system is switched to the atmosphere open state to perform a pumping cutoff operation in which pumping by the impeller is blocked, and in parallel with this pumping cutoff operation, the auxiliary pump is operated by the pump main shaft. Is operated to perform a pumping operation by the sub pump, and a method for operating a vertical shaft pump having a standby operation function.