JPH09287588A - Pump casing of underwater pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a plastic pump casing with high strength which forms a pump chamber in an airtight condition. SOLUTION: In order to form a pump chamber 19 within which an impeller 11 is arranged, plastic upper and lower cases 12, 13 are butted against each other while sandwiching a metal ring 16 therebetween. The metal ring 16 is heated by high frequency current, and then the upper and lower cases 12, 13 are welded each other at a peripheral edge of the metal ring 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows a peripheral fluid to be sucked into a pump chamber containing the impeller and discharged from the pump chamber by rotation of an impeller rotated by a motor. More specifically, the present invention relates to a pump casing of a submersible pump having a pump chamber formed therein by joining an upper case and a lower case made of plastic to each other.

[0002]

2. Description of the Related Art An example of a submersible pump installed in a sewer tank or the like is shown in FIG. The submersible pump is usually configured by arranging a pump casing 62 below a motor 61 arranged on an upper side, and an impeller 64 is attached to a lower end portion of a rotor shaft 63 which passes through a shaft center portion of the motor 61. Has been. The impeller 64 is located inside a pump chamber formed inside the pump casing 62. Such a submersible pump is placed in water at the bottom of a sewage tank or the like, and the impeller 64 is rotated, whereby fluid is sucked into the pump casing 62 and the pump casing 6
The fluid is discharged from the pump chamber in 2.

The pump casing 62 generally has an upper case 62a and a lower case 62b which are made of plastic, and the upper case 62a and the lower case 62b are made of a rubber packing 6 having an annular shape.
2c is sandwiched and is abutted against each other all around,
It is fastened by a plurality of bolts 62d. The packing 62c includes an upper case 62a and a lower case 62.
It is sandwiched between b and in a state of being pressed against each other over the entire circumference.

[0004]

In such a submersible pump, since the upper case 62a and the lower case 62b of the pump casing 62 are fastened by a plurality of bolts 62d, the circumference of each bolt 62d is strongly fastened. However, the pressure contact force between the bolts 62d adjacent in the circumferential direction is weakened. Therefore, when the submersible pump is used at a high lift and the pressure in the pump casing 62 rises, the peripheral surface portions of the upper case 62a and the lower case 62b may be deformed between the bolts 62d adjacent in the circumferential direction. There is. When such deformation occurs, the pressure contact force of the upper case 62a and the lower case 62b against the packing 62c is further reduced, which may impair the sealing property and cause water leakage.

In order to prevent the occurrence of such water leakage, it is necessary to increase the number of bolts 62d to narrow the fastening intervals of the bolts 62d in the pump casing 62, but the number of bolts 62d increases. Therefore, there is a problem that the economical efficiency is impaired and the efficiency of the assembling work is significantly reduced.

The present invention is intended to solve such a problem, and an object thereof is that an upper case and a lower case made of plastic are joined together with high strength over the entire circumference, and the joints of the two are wholly joined. An object of the present invention is to provide a pump casing for a submersible pump that is reliably kept airtight over the circumference.

[0007]

The pump casing of the submersible pump of the present invention has a pump chamber in which an impeller rotationally driven by a motor is housed.
A pump casing for a submersible pump, which is formed by joining an upper case and a lower case to each other. The upper case and the lower case are butted against each other with a metal ring interposed therebetween, and the metal ring is guided by a high frequency. The upper case and the lower case are welded by heating.

In the pump casing of the submersible pump according to a second aspect of the present invention, a groove is provided over the entire circumference in either one of the upper case and the lower case, and in the other case, a ridge is fitted into the groove. Is provided over the entire circumference, and the upper case and the lower case are welded in a state in which the metal ring is arranged in the concave groove and the convex strip is fitted in the concave groove.

According to a third aspect of the present invention, there is provided a pump casing for a submersible pump, wherein one of the upper case and the lower case is provided with a vent hole for communicating the inside and the outside of the pump chamber.
A valve chamber accommodating a valve body that opens and closes the vent hole is provided on the inner peripheral side of the metal ring.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partially cutaway side view showing an example of an embodiment of a submersible pump having a pump casing according to the present invention. This submersible pump is installed and used at the bottom of a sewage tank, the bottom of stored water at a construction site, and the like. This submersible pump includes a motor 20 arranged on the upper side and a motor 20
And a pump casing 10 in which an impeller 11 is arranged inside.

The motor 20 has a cylindrical stator casing 21 having a vertical axis, and a cylindrical stator 24 attached to the stator casing 21.
And a rotor 22 arranged in the hollow shaft center portion of the stator 24, and a rotor shaft 23 that passes through the shaft center portion of the rotor 22.

A disc-shaped bearing bracket 25 is fitted to the lower end of the stator casing 21. The lower end portion of the rotor shaft 23 extends through the shaft center portion of the bearing bracket 25 and extends downward, and is rotatably supported by the bearing 26 provided at the shaft center portion of the bearing bracket 25. The peripheral edge portion of the bearing bracket 25 is supported on the outer peripheral edge portion of the seal bracket 18 that covers the upper surface of the pump casing 10, and the plurality of bolts 2
9, the peripheral portions are integrally fastened.

Between the shaft center of the bearing bracket 25 and the shaft center of the seal bracket 18, an appropriate space is formed in the vertical direction, and the rotor shaft 2 is placed in the space.
3 is inserted vertically. A mechanical seal 27 is fitted to the rotor shaft 23 inserted between the bearing bracket 25 and the seal bracket 18.
This mechanical seal 27 allows the rotor shaft 2
3 is sealed. The rotor shaft 23 is inserted through the shaft center portion of the seal bracket 18, and the lower end portion thereof is inserted into the pump casing 10 located below the seal bracket 18. An impeller 11 is attached to a lower end of the rotor shaft 23 located inside the pump casing 10.

A motor cover 28, in which an electric system is housed, is attached to the upper side of the stator casing 21.

The pump casing 10 has an upper case 12 and a lower case 13 each made of plastic, and the upper case 12 and the lower case 13 project from each other with a metal ring 16 sandwiched therebetween. They are put together and welded by high frequency welding.

FIG. 2A is a bottom view of the upper case 12 in the pump casing 10, and FIG. 2B is a metal ring 1 provided between the upper case 12 and the lower case 13.
6 is a bottom view of FIG. 6 and FIG. 2C is a plan view of the lower case 13. Note that FIG. 1 is a cross-sectional view taken along the line AA of FIG. Further, FIG. 3A is an enlarged cross-sectional view of a joint portion between the upper case 12 and the lower case 13.

Inside the pump casing 10, a cylindrical pump chamber 19 for accommodating the impeller 11 and the pump chamber 1 are provided.
9 and a cylindrical discharge chamber 14 disposed adjacent to the discharge chamber 9. The pump chamber 19 and the discharge chamber 14 are each formed in a cylindrical shape, and the inner diameter of the discharge chamber 14 is smaller than the inner diameter of the pump chamber 19. Upper case 12
And the lower case 13 includes the pump chamber 19 and the discharge chamber 1.
4 has a gourd-shaped peripheral surface portion 12a and 13a forming the peripheral edge portion of 4, and the lower end surface of the peripheral surface portion 12a of the upper case 12 and the peripheral surface portion 13a of the lower case 13.
And the upper end surface of is sandwiched by the metal ring 16 and is welded by high frequency welding.

A circular opening 12c is provided in a portion of the upper case 12 above the pump chamber 19, and the opening 12c is formed in the seal bracket 18.
Covered by A circular discharge port 12d corresponding to the cross-sectional shape of the discharge chamber 14 is provided in a portion of the upper case 12 corresponding to the upper side of the discharge chamber 14. A discharge pipe (not shown) is provided on the peripheral portion of the discharge port 12d.
A mounting flange 30 for mounting is attached by bolts.

A valve chamber 12e communicating with the inside of the pump chamber 19 is provided in the peripheral surface portion 12a of the upper case 12 located between the pump chamber 19 and the discharge chamber 14. The valve chamber 12e is located on the inner peripheral side of the metal ring 16 and has a circular opening provided downward from the lower end surface of the upper case 12 so that the upper surface is formed in a cylindrical shape having a hemispherical shape. There is. The valve chamber 12e is in a closed state by being abutted against the upper end surface of the lower case 13,
The inside of the valve chamber 12e is provided with a pump chamber 1 through a communication hole 12f (see FIG. 2 (a)) provided at the lower end of the valve chamber 12e.
It communicates with the inside of 9. A ventilation hole 12g (see FIG. 1) is provided above the valve chamber 12e so as to vertically pass through the peripheral surface portion 12a of the upper case 12. This ventilation hole 1
2g is in a state of being opened upward from the upper surface of the upper case 12, and the inside of the valve chamber 12e is set to the pump casing 1
It communicates with the outside of 0.

Inside the valve chamber 12e is a spherical valve body 12h.
Is provided. When the submersible pump is stopped, the valve body 12h is in a state of descending to the lower part of the valve chamber 12e, and the vent hole 12g provided above is opened. On the other hand, the submersible pump is driven and the pump chamber 1
When the air pressure inside 9 rises, the valve body 12h rises inside the valve chamber 12e by the air pressure inside the pump chamber 19 and closes the vent hole 12g.

In the lower case 13 of the pump casing 10, a suction port 13c is provided at the center of the bottom surface that closes the pump chamber 19. In addition, a plurality of legs 13d are provided on the peripheral portion of the lower case 13 in a state of protruding downward.

FIG. 3 (b) is an exploded sectional view showing the upper case 12 and the lower case 13 before the upper case 12 and the lower case 13 are joined by high frequency welding. On the lower end surface of the peripheral surface portion 12a of the upper case 12, a concave groove 12b is provided over the entire circumference before joining by high frequency welding. The groove 12b is open downward and has a quadrangular cross section with a constant width in the vertical direction. And the groove 12
A metal ring 16 having a gourd shape similar to that of the peripheral surface portion 12a is fitted in b.

The peripheral surface portion 13 of the lower case 13
Before joining by high-frequency welding, a ridge 13b protruding upward so as to be fitted into the concave groove 12b of the upper case 12 over the entire circumference is provided on the upper end surface of a over the entire circumference. The ridge 13b has a quadrangular cross-section with a constant width in the vertical direction, and the protruding height thereof is the groove 12
It is slightly smaller than the depth of b.

In the upper case 12 and the lower case 13 as described above, the ridges 13 of the lower case 13 with the metal ring 16 fitted in the groove 12b of the upper case 12.
b is fitted into the groove 12b, and the upper case 12 and the lower case 13 are high-frequency welded while being pressed against each other. The high frequency welding is performed by arranging a heating coil so as to surround the periphery of the pump casing 10 and supplying a high frequency current to the heating coil. When a high-frequency current is applied to the heating coil, the metal ring 16 generates heat by induction heating, and the periphery of the metal ring 16 is in a molten state. As a result, the upper case 12 and the lower case 13 are welded to each other as shown in FIG.

The submersible pump having such a structure is used while the pump casing 10 is immersed in water.
When the pump casing 10 is immersed in water, the valve body 12h in the valve chamber 12e provided in the peripheral surface portion 12a of the upper case 12 is in a state of descending to the lower part of the valve chamber 12e,
The vent hole 12g provided above the valve chamber 12e is opened. Further, water flows into the pump chamber 19 through the suction port 13c. The water flowing into the pump chamber 19 discharges the air in the pump chamber 19 to the outside of the pump casing 10 through the ventilation hole 12g.

In this state, the rotor shaft 23 of the motor 20 is rotated and the impeller 11 arranged in the pump casing 10 is rotated. As a result, the fluid flows into the pump chamber 19 through the suction port 13c provided on the bottom surface of the lower case 13, becomes a vortex in the pump chamber 19, and is discharged from the discharge chamber 14 through the discharge port 12d. .

At this time, the air remains in the upper part of the pump chamber 19 in the pump casing 10, but the air remaining in the upper part of the pump chamber 19 enters the pump chamber 19 by the rotation of the impeller 11. It is mixed with the inflowing water and discharged together with the water. As a result, almost no air remains in the pump chamber 19.

By the rotation of the impeller 11, the pump chamber 19
When the internal pressure rises, the valve body 12h in the valve chamber 12e moves upward in the valve chamber 12e, and the valve chamber 12e
The ventilation hole 12g provided above the above is closed. As a result, there is no risk that water and air will flow out of the pump casing 10 through the vent holes 12g, and thereafter, by the rotation of the impeller 11, the fluid is reliably sucked into the pump chamber 19, It is surely discharged from the discharge chamber 14.

Further, in the pump casing 10, since the upper case 12 and the lower case 13 are welded by high frequency welding, both are surely hermetically sealed over the entire circumference, and It is securely joined over the entire circumference. Therefore, even if the submersible pump is used at a high lift and the pressure in the pump casing 10 rises, there is no risk of water or air leaking from the joint between the upper case 12 and the lower case 13, and the pump casing 10 There is no risk of deformation or damage.

Particularly, in the upper case 12 and the lower case 13, the recess 12b provided in the upper case 12 and the protrusion 13b provided in the lower case 13 are fitted to each other in a state where they are pressed against each other. Due to the high frequency welding, the upper case 12 and the lower case 13 are securely welded in an airtight state over the entire circumference.

Further, a valve chamber 12e, which accommodates a valve body 12h that opens and closes a vent hole 12g that communicates the inside and outside of the pump casing 10, is arranged inside the high-frequency welded portion of the upper case 12. Therefore, the valve chamber 12e is surely kept airtight.

The groove 12b provided on the lower end surface of the upper case 12 and the ridge 13b provided on the upper end surface of the lower case 13 do not need to have a constant width in the vertical direction. As shown in FIG. 4 (a), the ridges 13b
However, the cross-section has a tapered trapezoidal shape in which the width dimension becomes smaller toward the upper side, and the concave groove 12b is also aligned with the tapered ridge 13b, and the dimension in the width direction becomes gradually smaller toward the upper side. It may be formed in a trapezoidal cross section. In this case, since the width of the root of the ridge 13b is larger than that of the tip, the root of the ridge 13b melts with the upper case 12 as shown in FIG. 4 (b). Even if they are not integrated in the state, there is no possibility of breaking the root part.

[0034]

As described above, in the pump casing of the submersible pump of the present invention, since the upper case and the lower case are integrally welded by the high frequency welding, the upper case and the lower case are formed around the entire circumference. The airtight state is ensured over the upper case and the lower case, and the upper case and the lower case are joined to each other with high strength. Therefore, there is no risk of water or air leaking from the joint between the upper case and the lower case, and there is no risk of the upper case and the lower case breaking.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an example of an embodiment of a submersible pump provided with a pump casing of the present invention.

2 (a) is a bottom view of an upper case in a pump casing, FIG. 2 (b) is a bottom view of a metal ring provided between an upper case and a lower case, and FIG. 2 (c) is a bottom view. It is a top view of a case.

FIG. 3A is an enlarged cross-sectional view showing a joint portion between an upper case and a lower case of a pump casing, and FIG.
FIG. 4 is a transverse cross-sectional view showing an exploded state of the upper case and the lower case before joining.

FIG. 4 (a) is an exploded cross-sectional view showing another example of the embodiment of the pump casing of the present invention before joining the upper case and the lower case, and FIG. It is a cross-sectional view of the joining part of an upper case and a lower case.

FIG. 5 is a partially cutaway side view showing an example of a conventional submersible pump.

[Explanation of symbols]

 10 pump casing 11 impeller 12 upper case 12a peripheral surface portion 12b concave groove 12e valve chamber 12g vent hole 12h valve body 13 lower case 13a peripheral surface portion 13b ridge 13c suction port 14 discharge chamber 16 metal ring 19 pump chamber 20 motor 22 rotor 23 Rotor shaft 24 stator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Riki Takebe 1-1 1-1 Shinmeiwa-cho, Takarazuka-shi, Hyogo Prefecture Shinmeiwa Industry Co., Ltd. Industrial Machinery Systems Division (72) Yoshiyuki Horie Shinmeiwa, Takarazuka-shi, Hyogo No. 1 No. 1 Shinmeiwa Industry Co., Ltd. Industrial Machinery Systems Division (72) Inventor Katsunori Noda 6 107 Takinocho Nishinomiya-shi, Hyogo Shinmeiwa Industry Co., Ltd.

Claims (3)

[Claims] 1. A pump casing for a submersible pump, wherein an upper case and a lower case are joined to each other to form a pump chamber in which an impeller rotationally driven by a motor is housed. , The upper case and the lower case are abutted against each other with a metal ring interposed therebetween over the entire circumference, and the metal ring is induction-heated by high frequency, whereby the upper case and the lower case are welded together. Pump casing for the pump. 2. A groove is provided over the entire circumference in either one of the upper case and the lower case, and the other is
A convex strip to be fitted in the concave groove is provided all around, and the metal ring is arranged in the concave groove so that the convex strip fits in the concave groove. The pump casing of the submersible pump according to claim 1, which is welded. 3. A vent hole communicating between the inside and the outside of the pump chamber, and a valve chamber accommodating a valve body that opens and closes the vent hole, in either one of the upper case and the lower case.
The pump casing of the submersible pump according to claim 1, wherein the pump casing is provided on the inner peripheral side of the metal ring.