JPH0612787U - Vertical pump - Google Patents

Abstract

(57) [Summary] [Objective] The vertical pump P is allowed to be drained to a region below the minimum operable water level LWL of the prior art by avoiding the increase in size and restrictions on the installation space. [Structure] A plurality of through holes 11, 11 ... Are provided in a region below the operable minimum water level LWL peculiar to the vertical pump P of the suction cover 6.
Is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vertical shaft pump, and more particularly, to a vertical shaft pump that enables drainage at a water level lower than the minimum operable water level of the related art and enables construction of a raised bottom of an intake well.

[0002]

[Prior art]

 For example, the vertical pump P installed in the pump water intake well 1 of the drainage pump station shown in FIG. 2 has the lowest operable water level LWL unique to the vertical pump P, and the water level of the water intake well 1 is the lowest operable. If the drainage operation is performed in the region below the water level LWL, a vortex will be generated and the air-mixed water will be sucked. As a result, violent vibrations and loud noises may occur, causing pump operation dysfunction and damaging the foundation and building of the drainage pump station. Therefore, when the water level drops to the lowest operable water level LWL, the water level LWL is detected to stop the operation of the vertical pump P, or the impeller chamber 5 is provided with an intake pipe (not shown). In the pre-standby operation type vertical pump, operation control is performed by opening an intake valve (not shown) provided in the intake pipe to intake the impeller chamber 5 accommodating the impeller 4 to cut off pumping. Has been done.

However, in the conventional operation control in which the operation of the vertical pump P is stopped at the operable minimum water level LWL, or the intake water is sucked into the impeller chamber 4 and the pumping is cut off, the residual water amount of the water intake well 1 becomes the operable minimum water level. This corresponds to a depth D1 from the LWL to the bottom 1A of the water intake well 1 (approximately 1.7 times the bore of the pump), resulting in a large amount of residual water. Therefore, there is a demand to reduce the residual water amount by performing drainage operation to a region below the minimum operable water level LWL to make the depth to the bottom 1A of the water intake well 1 shallow. In order to satisfy such requirements, as shown in FIG. 3, a vertical shaft pump having a structure in which an enlarged bell mouth 7 having a large suction port is attached to the lower side of the suction cover 6 communicating with the lower side of the impeller chamber 5. P is proposed. According to this vertical shaft pump P, since the suction area becomes large, the suction flow velocity is reduced. Therefore, even if the drainage operation is performed in a region below the conventional operable minimum water level LWL, vortices are less likely to occur, and vibration and noise can be effectively suppressed. However, since the expanded bell mouth 7 having a considerably large suction port must be used, the vertical shaft pump P becomes large and requires a large installation space. Therefore, there is a problem in that the installation space is restricted. .

[0004]

[Problems to be solved by the device]

 The problem to be solved is that even if it is attempted to satisfy the requirement for drainage operation to a region below the conventional minimum operable water level, the conventionally proposed vertical pump requires a large size and a large installation space. Therefore, it is impossible to implement due to restrictions on the installation space.

[0005]

[Means for Solving the Problems]

 The present invention relates to a vertical shaft pump provided with a suction cover communicating with the lower side of the impeller chamber, wherein a plurality of through holes are formed in a region of the suction cover below a minimum operable water level specific to the vertical shaft pump. With the above features, the objective of enabling upsizing of vertical shaft pumps and avoiding restrictions on installation space to be able to perform drainage operation to a region below the conventional minimum operable water level was achieved.

[0006]

[Action]

 According to the present invention, even if the water level of the intake well becomes lower than the conventional operable minimum water level, not only the intake port of the suction cover but also the plurality of through holes formed in the region below the operable minimum water level. Since water is also sucked in, the suction flow rate from the suction port is reduced. Therefore, vortexes are less likely to occur even when the drainage operation is performed in the region below the conventional minimum operable water level, and vibration and noise can be effectively suppressed. Even if some of the plurality of through holes are exposed above the water surface, if the plurality of through holes are evenly formed around the entire circumference of the suction cover, the area below the minimum operable water level of the conventional case will be obtained. Then, the air flows into the impeller inside the impeller chamber in a state where the air is evenly dispersed in the circumferential direction. Therefore, since the mass of pumped water with respect to the impeller can be made uniform, it is possible to effectively suppress the generation of vibration and noise due to air suction.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of a vertical shaft pump according to the present invention. The same or corresponding parts as those of the conventional example will be described with the same reference numerals. In this figure, a suction cover 6 is connected in communication with the lower side of the impeller chamber 5 which rotatably accommodates the impeller 4 and is rotatably accommodated therein, and the upper side of the impeller chamber 5 (downstream). A pumping pipe 8 is connected to the side), and an elbow 9 and a discharge valve 10 are connected in series downstream of the pumping pipe 8 to form a vertical pump P, which is installed in the water intake well 1. The suction port of the suction cover 6 is set to a normal size (approximately 1.4 times the pump diameter), and a plurality of through holes 11, 11 are provided in the region below the conventional operable minimum water level LWL peculiar to the vertical shaft pump P. ... are formed evenly around the entire circumference.

With such a configuration, in a region where the water level of the water intake well 1 is higher than the conventional operable minimum water level LWL, water is sucked into the suction port 6A of the suction cover 6 and the plurality of through holes 11, 11 ... It is sucked in from and is pumped up (drained). On the other hand, even if the water level of the water intake well 1 falls below the conventional operable minimum water level LWL, water is sucked not only from the suction port 6A of the suction cover 6 but also from the plurality of through holes 11, 11 ... Therefore, the suction flow rate from the suction port 6A decreases. Therefore, eddies are less likely to be generated even if the drainage operation is performed in the area below the conventional operable minimum water level LWL, and vibration and noise can be effectively suppressed, so that in the area below the conventional operable minimum water level LWL. It becomes possible to perform drainage operation. Therefore, the residual water amount in the water intake well 1 becomes shallow corresponding to the depth from the lower level than the conventional operable minimum water level LWL to the bottom 1A of the water intake well 1, and the residual water amount can be reduced. Further, if the drainage stop water level is set to the same level, the bottom 1A of the water intake well 1 can be raised to make the water intake well 1 shallow, so the civil engineering cost for constructing the water intake well 1 can be significantly reduced. Moreover, unlike the conventional vertical pump P, since the enlarged bell mouth 7 is not required, the structure is simple and the installation space can be small, so that there is no restriction on the installation space. On the other hand, since the plurality of through holes 11, 11 ... Are evenly formed around the entire circumference of the suction cover 6, the through holes 11 exposed on the water surface in the region below the conventional operable minimum water level LWL. 11 ... Even if air is sucked in, the air will flow into the impeller 4 in the impeller chamber 5 in a state where the air is evenly dispersed in the circumferential direction. As a result, the mass of pumped water with respect to the vane wheel 4 can be made uniform, so that it is possible to effectively suppress the generation of vibration and noise due to the intake of air.

In the above-mentioned embodiment, the normal vertical pump P is explained, but it goes without saying that it can be applied to a preceding standby operation type vertical pump provided with an intake pipe and an intake valve provided in the intake pipe. Nor. The shape of the plurality of through holes 11, 11, ... Is arbitrary.

[0010]

[Effect of device]

 As explained above, according to the present invention, it is possible to perform drainage operation to a region below the conventional minimum operable water level by avoiding the increase in size of the vertical shaft pump and restrictions on the installation space. In addition to being able to reduce the water level, if the drainage stop water level is set to the same level, it will be possible to raise the bottom of the suction well to make it shallower, and significantly reduce the civil engineering cost for construction of the suction well. You can

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a conventional example.

FIG. 3 is a schematic configuration diagram showing another conventional example.

[Explanation of symbols]

 1 Water well 4 Impeller 5 Impeller chamber 6 Suction cover 11 Through hole P Vertical shaft pump LWL Operable minimum water level

Claims (1)

[Scope of utility model registration request] 1. A vertical shaft pump provided with a suction cover communicating with the lower side of an impeller chamber, wherein a plurality of through holes are formed in a region of the suction cover below an operable minimum water level peculiar to the vertical shaft pump. Vertical shaft pump characterized by having.