JPH11257273A - Submerged pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the generation of a no-load running which cannot pump up water in a restarting time by securing exhaust function of air infiltrated in a pump casing. SOLUTION: An elastic seal ring 5 is provided in an annular space between the inner periphery of a permeation hole in the vertical direction provided to a casing cover 8, and the outer periphery of the boss 3A of an impeller 3, and an air venting hole 19 is provided in the casing cover 8 at the upper side of the elastic seal ring 5, while a small clearance 20 with almost L-shape cross section to communicate the inside of the pump casing 1 with the lower side of the elastic seal ring 5, with the casing cover 8 and the upper surface of the outer peripheral edge of the impeller 3 opposing to the casing cover 8, is also formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a submersible pump, and more particularly to a submersible pump suitable for pumping sewage installed in a manhole or a sewage relay pumping station.

[0002]

2. Description of the Related Art A submersible pump of this type generally comprises a pump casing 1, a prime mover 2, an impeller 3, a mechanical seal 4, and an elastic seal ring 5, as shown in FIG. .

[0003] The pump casing 1 has a downwardly directed suction port 6 at the bottom thereof, a suction bell mouth 7 attached to the suction port 6, and a top cover closed by a casing cover 8, and the inside thereof is closed. Is formed with a swirl chamber 9 communicating with the suction port 6 and the suction bell mouth 7 and having a vertical axis, and a discharge passage 10 communicating with the swirl chamber 9 is formed on a side portion. The discharge passage 10 is formed by the discharge curved pipe 1.
1 and communicates with the pumping pipe 17.

The prime mover 2 is constituted by a submersible motor, and is mounted on the casing cover 8 and connected to the prime mover frame 12.
The interior is liquid-tight. Also, the output shaft 13 of the prime mover 2
Extends through the vertical through hole 14 provided in the casing cover 8 and extends into the pump casing 1, and the impeller 3 fixed to the tip end thereof is rotatably housed in the pump casing 1. I have.

The casing cover 8 and the motor frame 12
A mechanical seal accommodating portion 15 is provided therebetween, and a mechanical seal 4 surrounding the output shaft 13 is accommodated in the mechanical seal accommodating portion 15. The mechanical seal 4 prevents water from entering the prime mover frame 12. I have.

On the other hand, an elastic seal ring 5 formed of an elastic material such as rubber is provided in an annular space 16 between the inner periphery of the vertical through hole 14 provided in the casing cover 8 and the outer periphery of the impeller boss 3A. With the sealing action of the elastic seal ring 5, solid matter mixed into the sewage and entering the pump casing 1 is removed by the mechanical seal housing 15.
To protect the mechanical seal 4.

In this type of submersible pump, the pump operation stop water level LWL corresponds to the lower end of the suction bell mouth 7 in order to prevent accumulation of scum generated in a manhole or a sewage relay pumping station. In many cases, the operation is set to a low position and the operation is continued until the suction water tank 18 is almost empty. However, by adopting the operation method in which the operation stop water level LWL of the pump is set at such a low position, air enters the pump casing 1 through the suction bell mouth 7 and the suction port 6 when the operation of the pump is stopped. Some of the air that has entered has a water level HW
An air-lock state in which air remains in the pump casing 1 even when the air pressure rises to L, hinders the flow of water into the pump casing 1, and prevents pumping at the time of restart at the operation start water level HWL. Generate. For this reason, in the conventional submersible pump, the pump casing 1 is provided with the air vent hole 19, and the air is exhausted from the air vent hole 19, thereby preventing the occurrence of idle operation in which pumping is impossible at the restart at the operation start water level HWL. We are trying to avoid it.

However, in the configuration in which the air is discharged from the air vent hole 19 provided in the pump casing 1, the air vent hole 19 is blocked by the large solid matter mixed into the sewage and entering the pump casing 1, so that the air discharging function is reduced. There is a possibility that an idle operation in which pumping is impossible at the time of restart at the operation start water level HWL due to loss is generated.

Therefore, as shown in FIG. 3, an air vent hole 1 is formed in the casing cover 8 on the upper surface side of the elastic seal ring 5.
A submersible pump is provided which is provided so as to prevent the occurrence of idle operation in which water cannot be pumped at the restart at the operation start water level HWL by discharging air from the air vent hole 19.

According to this type of submersible pump, even if air enters the pump casing 1 through the suction port 6 when the operation of the pump is stopped, this air is used to raise the water level to the upper end level of the discharge passage 10. Accordingly, the water is replaced by the water flowing into the pump casing 1 and discharged from the discharge passage 10 to the outside of the pump casing 1. The water level is the discharge passage 1
Even when the water level rises to the upper end level of 0, the air still remaining in the pump casing 1 is elastically increased as the water level rises above the upper end level of the discharge passage 10 to the interposition position of the elastic seal ring 5. The air is discharged from the air vent 19 through a small annular gap (not shown) formed between the inner periphery of the seal ring 5 and the outer periphery of the impeller boss 3A.

On the other hand, the water level rises over the interposition position of the elastic seal ring 5 to the pump operation start water level HWL,
When the operation of the pump is started, the inner peripheral lip of the elastic seal ring 5 is deformed by the pressure increase in the pump casing 1 after the pump is started, and the annular small gap (not shown) is further reduced. Thereby, the air vent hole 1
9 can be prevented from entering.

However, in the configuration in which the air is discharged from the air vent hole 19 provided in the casing cover 8 above the elastic seal ring 5, the solid material intervenes in the small annular gap (not shown), so that the elastic seal ring The deformation of the inner peripheral lip portion 5 is prevented, and the function of reducing the annular gap (not shown) to a smaller size does not occur.
Subsequent solid matter passes through the small annular gap (not shown) and penetrates and accumulates in the air vent hole 19, and the air vent hole 19
Has the risk of blocking As described above, when the air vent hole 19 is closed by the solid matter, the air discharge function is lost, and an idle operation in which pumping is impossible at the time of restart at the operation start water level HWL occurs.

[0013]

That is, in the conventional submersible pump, the air vent hole is closed by the solid matter mixed into the sewage and entering the pump casing, and the function of discharging the air entering the pump casing is lost. This causes an idle operation in which pumping is impossible when the pump is restarted. Therefore, an object of the present invention is to provide a submersible pump that can ensure the function of discharging air that has entered the pump casing and can reliably avoid the occurrence of idle operation in which water cannot be pumped during restart.

[0014]

In order to achieve the above-mentioned object, a submersible pump according to the present invention has a downward suction opening at the bottom, a top closed by a casing cover, and A pump casing in which a swirl chamber having a vertical axis communicating with the suction port is formed, and a discharge passage communicating with the swirl chamber is formed on a side portion;
A motor that is liquid-tightly mounted in a motor frame connected to the casing cover; an output shaft of the motor that extends through a vertically-oriented through hole provided in the casing cover and extends into the pump casing; An impeller fixed to a shaft and rotatably housed in the pump casing; and a mechanical seal housing portion surrounding the output shaft and being housed between the casing cover and the prime mover frame. A mechanical seal for preventing intrusion of water, and a mechanical seal interposed between an inner periphery of a vertical through hole provided in the casing cover and an outer periphery of an output shaft or an impeller boss of the prime mover. A submersible pump having an elastic seal ring for preventing solid foreign matter from entering the storage section; The casing cover is provided with an air vent hole, and a small gap is formed between the casing cover and the outer peripheral edge of the impeller opposed to the casing cover so that the inside of the pump casing communicates with the lower side of the elastic seal ring. Is formed.

According to the present invention, the casing cover and the outer peripheral edge of the impeller facing the casing cover include:
Since a small gap is formed to allow the inside of the pump casing to communicate with the lower side of the elastic seal ring, the small gap acts like a liner ring interposed between the casing cover and the impeller. For this reason, the small gap allows only the passage of air and the passage of very small solid matter, but prevents the passage of other solid matter, and this solid matter is caused by the inner circumference of the elastic seal ring and the output shaft of the prime mover or It is possible to prevent a small annular gap formed between the impeller boss and the outer periphery of the impeller from intervening.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged sectional view showing a main part of an embodiment of the present invention. Since the overall structure of the submersible pump to which the present invention is applied is not different from the conventional example described with reference to FIG. 3, the description of its structure and operation will be omitted, and only the characteristic portions of the present invention will be described. FIG.
In the above, the casing cover 8 and the upper surface of the outer peripheral edge of the impeller 3 facing the casing cover 8 communicate with the inside of the pump casing 1 below the elastic seal ring 5 with a small gap 20 having a substantially L-shaped cross section. Is formed.

In the above configuration, when the pump operation stop water level LWL is set to a low position corresponding to the lower end of the suction bell mouth 7 and the operation is continued until the suction water tank 18 is almost empty, the suction operation is stopped when the pump stops operation. Air enters the pump casing 1 through the bell mouth 7 and the suction port 6. This air is replaced with water flowing into the pump casing 1 as the water level rises to the upper end level LWL1 of the discharge passage 10 when the operation of the pump is stopped, and is discharged from the discharge passage 10 to the outside of the pump casing 1, that is, the pumping water. It is discharged to the pipe 17 side.

The water level is at the upper end level LWL1 of the discharge passage 10.
Even if it rises, air remains in the pump casing 1. This residual air has a water level exceeding the upper end level LWL1 of the discharge passage 10 and the interposition position L of the elastic seal ring 5
As it rises to WL2, an L-shaped small gap 2
The air is discharged from the air vent hole 19 through a small annular gap (not shown) formed between the inner circumference of the elastic seal ring 5 and the outer circumference of the impeller boss.

On the other hand, when the water level rises to the pump operation start water level HWL beyond the interposition position LWL2 of the elastic seal ring, the L-shaped small gap 20 and the inner circumference of the elastic seal ring 5 and the impeller boss are formed. The air is discharged from the air vent hole 19 through a small annular gap formed between the outer periphery and the outer periphery.

On the other hand, the water level is the operation start water level HWL of the pump.
When the operation of the pump is started, the inner peripheral lip portion of the elastic seal ring 5 is deformed inward by the pressure increase in the pump casing 1 after the pump is started, and an annular small ring (not shown) is formed. Make the gap even smaller. Also, the small L-shaped gap 20 acts like a liner ring interposed between the casing cover 8 and the upper surface of the outer peripheral edge of the impeller 3. For this reason, the L-shaped small gap 20 allows only extremely small solids to pass, but blocks the passage of other solids. Therefore, it is possible to reliably prevent the air vent hole 19 from being blocked by the above-mentioned other solid matter, and to secure the function of discharging the air that has entered the pump casing by the air vent hole 19. The pumping operation can be started properly without idling when restarting.

In the above embodiment, the elastic seal ring 5 is provided on the casing cover 8 so that the vertical through hole 1 is provided.
4 is described in the configuration provided in the annular space 16 between the inner circumference of the impeller 3 and the outer circumference of the boss portion 3A of the impeller 3, but the present invention is not limited to the above-described embodiment, and the elastic seal ring is used. 5 is an annular space 16 between the inner circumference of the through hole 14 in the vertical direction provided in the casing cover 8 and the outer circumference of the output shaft 13 of the motor 2.
May be configured to be interposed.

[0022]

As described above, according to the present invention, a small gap is provided between the casing cover and the outer peripheral edge of the impeller opposed to the casing cover so that the inside of the pump casing communicates with the lower side of the elastic seal ring. , The small gap acts like a liner ring interposed between the casing cover and the impeller. For this reason, the small gap allows only the passage of air and the passage of very small solid matter, but prevents the passage of other solid matter, and this solid matter is caused by the inner circumference of the elastic seal ring and the output shaft of the prime mover or Since it is prevented from intervening in a small annular gap formed between the outer periphery of the impeller boss and the outer periphery of the impeller boss, the function of discharging air that has entered the pump casing is secured by the air vent hole, and when restarting with operation start water In this case, the pumping operation can be started properly without causing idle operation.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing an example of a conventional submersible pump.

FIG. 3 is a partial configuration diagram showing another example of a conventional submersible pump.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pump casing 2 motor 3 impeller 3A impeller boss 4 mechanical seal 5 elastic seal ring 6 suction port 8 casing cover 9 spiral chamber 10 discharge passage 12 motor frame 13 output shaft 14 through hole 15 mechanical seal housing 16 annular space 19 Air vent hole 20 Small gap with almost L-shaped cross section (small gap)

Claims (1)

[Claims] 1. A downwardly directed suction port is opened at a bottom portion, an upper portion is closed by a casing cover, and a swirl chamber communicating with the suction port and having a vertical axis is formed therein. A pump casing in which a discharge passage communicating with the volute chamber is formed, a prime mover liquid-tightly mounted on a prime mover frame connected to the casing cover, and a vertical through hole provided in the casing cover. An output shaft of a motor that penetrates and extends into the pump casing; an impeller fixed to the output shaft and rotatably housed in the pump casing; a casing cover surrounding the output shaft and the motor; A mechanical seal housed in a mechanical seal housing portion between the frames to prevent water from entering the prime mover frame, and the casing cover An elastic seal interposed in an annular space between the inner periphery of the vertical through-hole provided in the motor and the outer periphery of the output shaft of the prime mover or the outer periphery of the impeller boss to prevent solid foreign matter from entering the mechanical seal accommodating portion. In a submersible pump including a ring, an air vent hole is provided in the casing cover above the elastic seal ring, and the casing cover and an outer peripheral edge of the impeller facing the casing cover, A submersible pump, wherein a small gap is formed to connect the inside of the pump casing to a lower side of the elastic seal ring.