JPH1077984A - Leading standby vertical pump - Google Patents

Abstract

(57) [Summary] [Problem] It is difficult to suck floating debris from a pump well, and there is a width between the water level to start water supply and the water level to stop water supply. There is no leading standby vertical pump. SOLUTION: One end 12a (open end) of an intake pipe 12 is vertically arranged in a pump well 8, and further includes a hollow cylindrical dust rejection device 14 surrounding an end of the intake pipe at an interval. The dust-repelling device 14 includes an upper end 14a fixed above the end of the intake pipe, an intermediate part 14b extending vertically from the upper end to below the end of the intake pipe, and a lower end 14 opening downward.
c, and a plurality of through-holes 15 are provided in an intermediate portion above the end of the intake pipe. One end of the intake pipe has an opening 16 whose area gradually increases downward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical stand-by type vertical shaft pump which can be started even when a pump well is low and can stand by in an operating state.

[0002]

2. Description of the Related Art In recent years, with the rapid progress of urbanization and land use in a basin, rainwater that has fallen is hardly absorbed by the ground. For this reason, when the amount of rainfall is large, a large amount of rainwater flows into the pumping station in a short time after the rainfall. In order to cope with such a rapid inflow of rainwater, a leading standby vertical shaft pump which can be started even in a state where the water level of a pump well is low and which can stand by at full speed operation has been conventionally used. In addition, the preceding standby type vertical shaft pump is used not only for a pump station but also for drainage of agricultural land and other drainage.

FIG. 5 is an overall configuration diagram of a conventional prior standby type vertical shaft pump. As shown in this figure, the leading standby type vertical pump comprises an impeller 1, a bell mouth 2, a main shaft 3, a casing 4, a suspension pipe 5, a discharge elbow 6, an intake pipe 7, and the like, and a diesel engine (not shown). ), The impeller 1 is rotated via the main shaft 3. This rotation causes the pump well 8 to move from the open end (lower end) of the bell mouth 2.
The rainwater or the like collected in the tank is sucked and drained through the casing 4, the discharge elbow 6, and the like.

The intake pipe 7 has one end 7a (open end) opening into the pump well 8 at a position slightly higher than the impeller 1, and the other end 7b opening into the bell mouth 2 below the impeller 1. I have. When one end 7a of the intake pipe 7 is located above the water level of the pump well 8, air flows through the bell mouth 2 through the intake pipe 7.
, The impeller 1 runs idle and no drainage is performed.
Conversely, when the open end 7a of the intake pipe 7 is located below the water level of the pump well 8, the intake pipe 7 is closed with water, so that no air flows in, the impeller 1 functions normally, and drainage is performed. Will be Therefore, the drainage (water supply / stop) of the pump can be automatically controlled based on the water level of the pump well 8 by keeping the preceding standby type vertical shaft pump in the operating state.

[0005]

FIG. 6 is a diagram showing a conventional configuration of an open end portion of an intake pipe 7. As shown in FIG. As shown in this figure,
The conventional open end 7a has a shape obtained by cutting the end of the intake pipe 7 perpendicularly to its axis. However, since a lot of dust is floating in the suction well of the standby operation type pump, the floating dust is sucked in from the open end of the intake pipe, and this dust is clogged in the intake pipe, obstructing the intake and causing the above-mentioned prior art. There is a problem that the operation of the stand-by vertical pump is deteriorated, or that the pump sucks air from the lower end of the bell mouth 2 to cause abnormal vibration and damage the pump.

Also, as described above, the leading standby type vertical shaft pump controls water supply / stop according to the water level. Therefore, in the conventional leading standby type vertical shaft pump, frequent vertical movements (for example, waving) of the water level in the conventional standby type vertical pump are frequent. Water supply / stop was repeated, and hunting and abnormal vibration could be caused.

The present invention has been made to solve such a problem. That is, a main object of the present invention is to provide a vertical stand-by type vertical shaft pump which is hard to suck floating dust from a pump well. Another object of the present invention is to
An object of the present invention is to provide a vertical stand-by type vertical pump that has a width between a water level at which water is started and a water level at which water is stopped, and does not switch between water supply and stop with a small water level fluctuation.

[0008]

According to a first aspect of the present invention, there is provided an intake pipe having one end opened into a pump well at a position higher than the impeller and the other end opened into a bell mouth below the impeller.
In a vertical stand-by type vertical pump for controlling water supply / stop by suction of air from the intake pipe, the one end of the intake pipe is vertically disposed in a pump well, and further has a hollow cylinder surrounding an end of the intake pipe at a distance. An upper end portion fixed above the end of the intake pipe, an intermediate portion extending vertically from the upper end to below the end of the intake pipe, Has an open lower end, and a plurality of through holes are provided in an upper portion of the intermediate portion above an end portion of the intake pipe. According to a preferred embodiment of the present invention, the maximum size of the through hole is smaller than the inner diameter of the intake pipe, and the total area of the through hole is set to be sufficiently larger than the internal area of the intake pipe.

According to the configuration of the present invention described above, since a plurality of through holes are provided in the intermediate portion above the end of the intake pipe, the end of the intake pipe is positioned at least slightly above the water surface. When the air is sucked, the through-hole is located further upward, so that the through-hole is located at a position sufficiently higher than the water surface, and dust floating on the water surface cannot flow into the dust-repelling device. Therefore, only the air passing through the through hole can be sucked from the end of the intake pipe without sucking dust. Also, when the through hole in the middle part is located near the water surface, the end of the intake pipe is completely submerged, so there is no air suction from the intake pipe and there is almost no flow through the through hole, so the The floating debris only floats on the surface and does not flow into the debris prevention device. In particular, by setting the maximum size of the through hole smaller than the inner diameter of the intake pipe and setting the total area of the through hole sufficiently larger than the inner area of the intake pipe, the intake pipe can be clogged without impairing the function of the intake pipe. Inflow of garbage of a size can be prevented.

In other words, when the open end comes out of the water surface,
If there is no dust around, dust can be prevented from being sucked in. Therefore, an outer cylinder (an intermediate portion of the dust-repelling device) is provided near the opening of the intake pipe to prevent dust from entering. In addition, since the structure is such that air flows through the hole at the top of the outer cylinder, dust near the water surface does not enter the open end. Also, when there is a water level at the hole of the outer cylinder, no air is sucked in, so that a flow occurs there and no inflow of dust occurs. Therefore,
By installing such a dust-repelling device, failure due to clogging of dust can be prevented, and highly reliable operation can be performed.

According to the second aspect of the present invention, there is provided an intake pipe open at one end into the pump well at a position higher than the impeller and open at the other end into a bell mouth below the impeller. A vertical stand-by type vertical shaft pump for controlling water supply / stop by suction of air, wherein the one end of the intake pipe has an opening whose area gradually increases downward. You.

[0012] With this configuration, a sudden change in the amount of air is avoided, and the air inflow area of the opening gradually changes due to a change in the water level. Therefore, a sudden change in the operating state of the pump body is prevented. It is possible to realize a stable operation of the preceding standby type vertical pump without repeating standby / drainage due to a slight change in (e.g., fluctuation of the water surface).

[0013]

Preferred embodiments of the present invention will be described below with reference to the drawings. In each of the drawings, common portions are denoted by the same reference numerals, and redundant description will be omitted. FIG. 1 is an overall configuration diagram of a leading standby vertical shaft pump according to the present invention. As shown in FIG. 1, the leading standby vertical shaft pump 10 according to the present invention includes an impeller 1, a bell mouth 2, a main shaft 3, a casing 4, a suspension pipe 5, a discharge elbow 6, and the like, and a diesel engine (not shown). 3)
To rotate the impeller 1. By this rotation, rainwater or the like collected in the pump well 8 is sucked from the open end (lower end) of the bell mouth 2 and drained through the casing 4, the discharge elbow 6, and the like. The impeller 1 is a mixed flow impeller in this figure, and the pump is a mixed flow pump.
The present invention is not limited to this, and may be a centrifugal type or an axial type as long as it is a vertical pump. Such a configuration is the same as that of the conventional prior standby type vertical shaft pump shown in FIG.

The leading standby vertical shaft pump 10 of the present invention further includes an intake pipe 12. One end 1 of this intake pipe 12
2 a (open end) is opened in the pump well 8 at a position slightly higher than the impeller 1, and the other end 12 b is opened in the bell mouth 2 below the impeller 1. The open end of the intake pipe 12 is disposed vertically (vertically) in the pump well 8.

Further, the vertical stand-by type vertical pump 10 of the present invention.
Is provided with a hollow cylindrical dust-repelling device 14 surrounding the intake pipe end 12a at a distance.

FIG. 2 is a diagram showing the configuration of the opening end of the intake pipe of FIG. 1. FIG. 2A shows a case where the end of the intake pipe is located near the water surface.
(B) shows a case where the end of the intake pipe is submerged.
As shown in FIG.
a, an intermediate portion 14b, and a lower end portion 14c having an open lower portion. The upper end 14a is located at the end of the intake pipe 12 (open end 1).
It is fixed by welding or the like above 2a). Intermediate part 14
b vertically extends from the upper end 14a to a position below the intake pipe end 12a. Further, a plurality of through holes 15 are provided in a portion of the intermediate portion 14b above the intake pipe end 12a.

The maximum size of the through hole 15 is smaller than the inner diameter of the intake pipe 12, and the total area of the through hole 15 is
Is set to be sufficiently larger than the inner area of the intake pipe 12 so as to prevent the inflow of dust 9 having such a size as to block the intake pipe 12 without impairing the function of the intake pipe 12.

According to the configuration of the present invention described above, the intermediate portion 1
4b, a plurality of through-holes 1 are provided above the intake pipe end 12a.
2, when the intake pipe end 12 a is located slightly above the water surface and sucks air as shown in FIG. 2A, the through hole 15 is located further upward, so The hole 15 is located at a position sufficiently higher than the water surface, and the refuse 9 floating on the water surface cannot flow into the refuse prevention device 14,
Therefore, only the air that has passed through the through-hole 15 can be sucked from the intake pipe end 12a without sucking the dust 9. Also, as shown in FIG. 2B, when the through hole 15 of the intermediate portion 14b is located near the water surface, the intake pipe end 1
Since 2a is completely submerged, there is no suction of air from the intake pipe 12, and there is almost no flow through the through-holes 15. Therefore, the refuse 9 floating on the water surface only floats on the surface and enters the refuse preventer 14 Does not flow.

FIG. 3 is a view showing an embodiment of the intake pipe open end, and FIG. 3 (A) shows the intake pipe open end (left figure) and its characteristics (right figure) shown in FIG. . In this figure, one end 12a of the intake pipe 12 has an opening 16a whose area gradually increases downward. That is, in this drawing, one end 12a of the intake pipe 12 is cut obliquely, and the opening 16a has an oblique elliptical shape.
By having such an opening 16a, when the water level is located at the upper end of the ellipse, the opening area for sucking air is zero, and when the water level is located at the lower end of the ellipse, the opening area becomes maximum, and during that time, the opening area becomes downward. The opening area gradually increases. Therefore, with this configuration, a sudden change in the amount of air is avoided, and a change in the water level gradually changes the air inflow area of the opening 16a. It is possible to realize a stable operation of the preceding standby type vertical pump without repeating water supply / stop (that is, drainage / standby) due to a slight change in (e.g., fluctuation of the water surface).

FIGS. 3B and 3C are diagrams showing another embodiment of the opening end of the intake pipe, and the characteristics thereof are shown on the right side. In this figure, FIG.
Has a plurality of through-holes 16b at the end 12a, and the number of the through-holes 16b increases toward the bottom, whereby the opening area gradually increases downward. In FIG. 3C, a vertical slit 16c is provided in the end portion 12a of the intake pipe 12, and the opening area gradually increases downward by the slit 16c. In addition,
The width of this slit may be constant or may be a shape that spreads downward.

The openings (B) and (C) described above also
As in the case of the opening 16a in FIG. 3A, a sudden change in the amount of air is avoided, and the air inflow area of the opening gradually changes due to a change in the water level. Can be prevented.

FIGS. 4A and 4B are explanatory diagrams of the operation of the vertical stand-by type vertical shaft pump according to the present invention, wherein FIG. 4A shows an in-air operation, FIGS. 4B and 4D show a gas-water mixing operation, FIG. E) shows an airlock state. In this figure, when the vertical stand-by pump 10 of the present invention is started in a state where the water level in the pump well is low, the air-operated state shown in FIG. 1 (impeller) becomes idle. Next, when the water level reaches the lower end of the impeller blade, drainage is started. At the water level below a certain level (LWL) after the start of drainage, the air flows into the pump from the intake pipe whose end is open to the atmosphere due to the pressure difference from the pump suction pressure. ).
In this operation state, the flow state in the impeller is disturbed due to the mixing of a large amount of air, and the performance is deteriorated.

When the suction water level further rises and the end of the air pipe is submerged and closed, the air stops flowing and the normal drain operation (C) is performed. In addition, when the discharge amount becomes larger than the pump well inflow amount, the suction water level drops, the end of the intake pipe is opened to the atmosphere, and the pump suction pressure becomes lower than the atmospheric pressure.
The air-water mixing operation (D) is performed in the same manner as (B). When the water level fluctuates up and down, the normal operation (C) and the air / water mixing operation (D) are alternately repeated, but the preceding standby vertical shaft pump of the present invention is provided with the above-described dust-repelling device 14. Therefore, it is difficult to suck floating debris from the pump well, and there is a width between the water level to start water supply and the water level to stop water supply,
Switching of water supply / stop does not occur with slight water level fluctuation,
Stable operation can be continued.

(F) When the water level further decreases and the discharge amount decreases, the dynamic pressure decreases before the impeller, so that the suction pressure approaches the atmospheric pressure and the air amount also decreases. When the water level falls to the air port level, the discharge amount becomes zero, but some air continues to flow in due to the impeller stirring the water.
At this time, both the shaft power and the discharge pressure are high in a so-called shutoff operation. Further, since the vibration of the pump becomes maximum immediately before the discharge amount becomes zero, if the discharge amount and the inflow amount are balanced at this point, the operation state becomes unstable. After the shut-off state continues for a while, the flow state near the impeller changes, an air layer is formed near the air port, and the water runs out, resulting in an idling state (air lock state). Thereafter, when the water level rises again, the state returns to (B).

Therefore, by operating the vertical stand-by pump 10 in the operating state by the operations (A) to (F), it is difficult to suck up the floating debris from the pump well. Drainage by pump (water supply / stop) according to the water level of pump well 8 without switching
Can be controlled automatically.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0027]

As described above, the vertical standby vertical pump according to the present invention is difficult to suck the floating debris from the pump well, and has a width between the water level at which water is started and the water level at which water is stopped. The switching of water supply / stop does not occur in the case of a small water level fluctuation, thereby having an excellent effect of preventing hunting and abnormal vibration.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vertical standby type vertical pump according to the present invention.

FIG. 2 is a configuration diagram of an opening end of an intake pipe in FIG. 1;

FIG. 3 is a diagram showing an embodiment of an intake pipe open end;

FIG. 4 is an explanatory view of the operation of the preceding standby type vertical shaft pump of the present invention.

FIG. 5 is an overall configuration diagram of a conventional advance standby type vertical shaft pump.

FIG. 6 is a configuration diagram of an open end portion of a conventional intake pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impeller 2 Bell mouth 3 Main shaft 4 Casing 5 Hanging pipe 6 Discharge elbow 7 Intake pipe 7a One end (open end) 7b Other end 8 Pump well 9 Dirt 10 Preparatory standby vertical shaft pump 12 Intake pipe 12a One end (opening) End) 12b Other end 13 Opening 14 Dust prevention device 14a Upper end 14b Intermediate part 14c Lower end 15 Through hole 16a Opening 16b Through hole 16c Slit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Tsuruharu Arai 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishikawashima-Harima Heavy Industries, Ltd. Inside the Yokohama Engineering Center (72) Inventor, Toshihiro Terada Isogo, Yokohama-shi, Kanagawa 1 Shin-Nakahara-cho, Ward Ishikawajima-Harima Heavy Industries, Ltd. Yokohama Engineering Center

Claims (3)

[Claims] 1. An intake pipe having one end opened into a pump well at a position higher than an impeller and the other end opened into a bell mouth below the impeller, and water is supplied / stopped by suction of air from the intake pipe. In the controlled standby type vertical pump, the one end of the suction pipe is vertically disposed in a pump well, and further includes a hollow cylindrical dust rejection device surrounding the end of the suction pipe at a distance. The apparatus has an upper end fixed above the end of the intake pipe, an intermediate part vertically extending from the upper end to below the end of the intake pipe, and a lower end opened at the lower side, and the intermediate part A plurality of through holes are provided in an upper portion of the end of the intake pipe. 2. The apparatus according to claim 1, wherein the maximum size of the through hole is smaller than the inner diameter of the intake pipe, and the total area of the through hole is set sufficiently larger than the internal area of the intake pipe. Pre-standby vertical shaft pump. 3. An intake pipe open at one end into a pump well at a position higher than the impeller and the other end open at a bell mouth below the impeller, and water is supplied / stopped by sucking air from the intake pipe. A leading standby vertical shaft pump to be controlled, wherein said one end of the intake pipe has an opening having an area gradually increasing downward.