KR101797096B1 - Centrifugal pump with reduced leakage loss between casing and impeller - Google Patents

Abstract

The present invention relates to a centrifugal pump with reduced leakage loss between a casing and an impeller. The centrifugal pump which includes a casing (100) and an impeller (200) rotated in the casing (100), comprises: a casing wear ring (230) which has one ring-shaped concave portion (R) formed to be inclined downwards right with a short upper inner surface and a long lower inner surface; an impeller wear ring (240) which is provided with one horizontal ring-shaped protrusion (241) having an upper surface thereof coming in surface contact with the ring-shaped concave portion (R) of the casing wear ring (230) and coupled to protrude in the ring-shaped concave portion (R), and in which a horizontal ring-shaped concave portion (r) formed at the lower portion of the horizontal ring-shaped protrusion (241) comes in surface contact with the end portion of the lower inner surface of the ring-shaped concave portion (R) of the casing wear ring (230); and one U-shaped cross sectional fine ring-shaped chamber (C) which is formed by coupling between the ring-shaped concave portion (R) of the casing wear ring (230) and the horizontal ring-shaped protrusion (241) of the impeller wear ring (240).

Description

[0001] The present invention relates to a centrifugal pump having reduced leakage loss between a casing and an impeller,

The present invention relates to a centrifugal pump in which a leakage loss due to a pressure difference between a high-pressure portion and a low-pressure portion inside a casing is reduced by an annular chamber formed by an annular concave portion of a casing wear ring and an annular projection of an impeller wear ring formed in a casing and an impeller of a centrifugal pump .

1 to 3, and a casing cover 140 is installed on one side of a casing 10 having an inlet end 12 and an outlet end 14 formed therein. The casing cover 140 has a large diameter inlet The impeller 20 maintains the airtightness of the space portion provided with the impeller 20 having the step 12 and the outlet end 14 having a small diameter and the impeller 20 is assembled close to the inside of the casing 10 and the casing cover 140 do. The impeller 20 is coupled with the impeller wear ring 40 so that the casing 10 and the impeller 20 are brought into close contact with each other with the minute clearance t therebetween. The impeller wear ring 40 is generally made of stainless steel or bronze for preventing rusting and durability.

In the conventional centrifugal pump constructed as above, when the power is applied to the motor, the impeller 20 rotates, the air in the casing 10 is discharged by the rotation of the impeller 20, the air pressure is lowered, So that the inlet end 12 and the outlet end 14 of the impeller 20 have a pressure difference and suck fluid through the inlet end 12 of the casing 10. [ At this time, the fluid sucked into the casing 10 is compressed in the casing 10 and discharged at a higher pressure. As the pressure of the fluid in the casing 10 becomes higher, A high pressure acts on the input end 12 side to cause the fluid in the casing 10 to leak through the micro gap t between the casing 10 and the impeller wear ring 40. Depending on the use period of the centrifugal pump Wear is generated in the casing 10 and the impeller wear ring 40, and leakage increases when the gap is wide (t ') (see FIGS. 3A and 3B).

 If the micro clearance t is excessively reduced, the casing 10 and the impeller wear ring 40 may be restrained from each other and may be rendered inoperable. During the long term operation stop, the surface of the special material of the impeller wear ring 40 may rust When the power switch is operated without knowing such a state, the motor is restrained and burned, and therefore, the motor 10 needs to be replaced and the entire casing 10 and the impeller wear ring 40 must be exchanged.

In order to prevent such a problem, when the gap t between the casing 10 and the impeller wear ring 40 is increased, problems such as motor burnout can be solved, but the performance of the centrifugal pump is deteriorated.

In order to overcome such problems of the prior art, Korean Patent Laid-Open Publication No. 1998-017629 entitled " Wear Ring Structure of Centrifugal Pump "has been proposed.

The present invention is characterized in that in the centrifugal pump including the casing 10 in which the impeller 20 is incorporated, a gas tight material 40, which is an elastic rubber having an elastic force, is applied between the impeller 20 and the casing 10 and the casing cover 140 And is disposed between the seating portion formed on the casing 10 and the casing cover 140 and the flat surface portion formed on the left and right ends of the impeller 20. [

Since the airtightness of the resilient elastic rubber material is provided in the above conventional technique, the leakage loss can be minimized by forming a sealing structure, thereby improving the efficiency of the centrifugal pump and improving the operational reliability of the centrifugal pump .

However, since an airtight material of a separate elastic rubber material is required to be provided, the number of parts is increased, which is cumbersome to manufacture and is made of an elastic rubber material. Therefore, durability is low and is easily broken. As a result, leakage can not be prevented even after a short- The pumping efficiency is lowered.

In addition, there is a problem that performance improvement can not be fundamentally achieved unless the gas tight material is replaced.

Korean Patent Publication No. 10-1998-017629 (published Jun. 5, 1998)

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a centrifugal pump in which a contact portion between a casing wear of a centrifugal pump and an impeller wear ring is constituted by a micro-layered chamber type structure and a leakage loss between the casing and the impeller is reduced It has its purpose.

According to an aspect of the present invention, there is provided a centrifugal pump including a casing and an impeller rotating inside the casing, the centrifugal pump comprising: an annular concave portion having an upper inner surface and a lower inner surface, A casing wear ring mounted on the inner surface of the casing; And an upper annular projection which is in close contact with an end of the upper inner surface of the annular recess of the casing wear ring in a face-to-face contact and which is protrudingly engaged in the annular recess, wherein the horizontal annular recess An impeller ware ring in which the lower surface of the portion is in surface contact with the end of the lower inner surface of the annular recess of the casing wear ring; A micro annular chamber having a U-shaped cross section formed by engagement of an annular recess of the casing wear ring and a horizontal annular protrusion of the impeller wear ring; And a centrifugal pump having a reduced leakage loss between the casing and the impeller.

According to one aspect of the present invention, the casing wear ring is provided with a plurality of annular recesses formed in layers, and the impeller wear ring has a number of horizontally-shaped annular protrusions formed corresponding to the annular recesses of the casing wear ring , And a number of micro annular chambers equal to the annular recesses of the casing wear ring.

According to another aspect of the present invention, there is further provided an annular concave portion or an annular concave portion at the lower end of the one or more annular concave portions of the casing wear ring, and an additional annular concave portion formed at the lower portion thereof in an inclined layer, A further annular recess of the casing wear ring is closed by the extension of the lower annular recess of the additional annular recess or the further annular recess of the lower portion of the impeller wear ring to form a further tetrahedral annular chamber .

According to another aspect of the present invention, an extension of the lower surface of the horizontal annular recess of the impeller wear ring in the tetragonal additional annular chamber may have a step downwardly or upwardly in the middle.

According to a further aspect of the present invention, the casing wear ring further comprises a further annular recess formed in the lower portion with an annular recess at the lower end thereof, wherein a further annular recess of the casing wear ring And can be closed by the extension of the lower surface of the lower horizontal annular recess to form a tetrahedral additional micro annular chamber.

According to another aspect of the present invention, an extension of the lower surface of the horizontal annular recess of the impeller wear ring in the rectangular additional annular chamber may have a downwardly or upwardly stepped portion in the middle.

According to another aspect of the present invention, an inner end face of the annular concave portion of the casing wear ring and the horizontal annular concave portion of the impeller wear ring may be triangular, polygonal or circular, or may be formed at right angles, acute angles, or obtuse angles to the flat sides have.

According to the present invention, a vortex of the leakage fluid is formed in one fine chamber or a plurality of layered fine chambers between the casing and the impeller of the centrifugal pump formed by the annular recesses of the casing wear ring and the annular protrusions of the impeller wear ring, The leakage loss is reduced and the pumping efficiency of the centrifugal pump is improved.

1 is a cross-sectional view of a centrifugal pump according to a conventional technique.
Fig. 2 is an enlarged cross-sectional view of a part of the centrifugal pump of Fig. 1;
FIG. 3A is a cross-sectional view illustrating a horizontal flow path formed between the impeller wear ring and the casing in the centrifugal pump of FIG. 1. FIG.
FIG. 3B is a cross-sectional view illustrating a state in which a width of a horizontal flow path is increased due to abrasion on a contact surface between the impeller wear ring and the casing in the centrifugal pump of FIG. 1;
4 is a cross-sectional view of a centrifugal pump according to an embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a substantial part of the centrifugal pump of FIG. 4;
Figs. 6A and 6B are cross-sectional views showing a micro-annular chamber formed between a casing wear ring and an impeller wear ring in the centrifugal pump of Fig. 4, and a leakage flow passage between the casing wear ring and the impeller wear ring.
FIGS. 7A and 7B are cross-sectional views for explaining the structure of the casing wearer and the impeller wear ring in the centrifugal pump of FIG. 4, and the vortices of the micro-annular chamber between the casing wear and the impeller wear ring.
8A and 8B are explanatory diagrams showing embodiments of a casing wear ring and an impeller wear ring in the centrifugal pump of FIG.
Fig. 8 is an exploded view showing the casing wear ring of the centrifugal pump of Fig. 4, the impeller wear ring, and the coupling structure of the impeller.
Fig. 9 is a partially cutaway perspective view showing the casing wear ring of the centrifugal pump of Fig. 4, the impeller wear ring, and the structure of the impeller.

Hereinafter, a centrifugal pump of a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals, thereby avoiding the complicated explanation.

As shown in Figs. 4 to 6, the centrifugal pump in which the leakage loss between the casing and the impeller is reduced according to one embodiment of the present invention includes a casing 100, In the centrifugal pump including the impeller 200,

A casing wear ring 230 mounted on the inner surface of the casing 100 and having five annular recesses (R, R ') formed in a layer shape with an upper inner surface short and a lower inner surface long and inclined downward to the right;

The upper surface and the lower surface of the horizontal annular recess r are in surface contact with the upper and lower ends of the four annular recesses R of the casing wear ring 230 Four horizontal annular protrusions 241 protruding into the four annular recesses R and a lower horizontal surface formed to be in surface contact with the lower ends of the annular recesses R ' An impeller wear ring (240) having an extension (ext) of the lower surface of the annular recess (r); And

The four annular recesses R of the casing wear ring 230 and the annular recesses R of the lower end and the four horizontal annular protrusions 241 of the impeller wear ring 240 and the horizontal annular recess r of the lower end of the casing wear ring 230, (C) and four additional annular fine chambers (C ') formed in layers by the engagement of extensions (ext) having a step on the lower surface of the lower surface of the annular chamber (C).

The unexplained reference character X not included in the above description is an open recess formed in the process of forming the annular recess R of the casing wear ring 230 and is not related to the technical structure of the present invention.

The casing wear ring 230 and the impeller wear ring 240 installed between the casing 100 and the impeller 200 of the centrifugal pump of the embodiment of the present invention are formed in the casing 100 and the impeller 200, Are mounted on the face portions 136 and 236 and fixed with bolts and nuts as in the prior art, but may be fixed by other methods such as press fitting.

The annular recesses R and R 'of the casing wear ring 230 and the horizontal annular protrusions 241 of the impeller wear ring 240 have a constant pitch distance pt' 'and a height h' ''), And five micro-annular chambers C and C 'are formed to be slanted and layered by being opposed to each other, and a micro clearance t1 is formed at a portion abutted against each other by surface contact.

Due to such a structure, the micro annular chambers C and C 'of the centrifugal pump are moved from the low pressure region P1 on the inlet end 21 side of the casing 100 to the outlet end The angle of inclination is not limited to 20 degrees, and it is experimentally determined that the angle of the inclined angle is 20 deg. To 10 deg. To 50 deg. Of the total design.

In the process of pumping the fluid, a flow path is formed in the minute gap t1 between the casing wear ring 230 and the impeller wear ring 240 by the pressure of the fluid to be pumped, so that the fluid flows and leakage occurs. The fluid flowing into the first fine chamber C is reduced in pressure as the flow volume increases and the flowing fluid collides against the wall of the first fine chamber C to form a vortex, The action also occurs in the second to fifth microchambers C and C 'following the first microchamber C and the pressure of the leakage fluid is greatly reduced when passing through the fifth microchamber C' The amount of fluid becomes extremely small.

In the description of the above embodiment, the four annular recesses R of the casing wear ring 230 and the additional annular recess R 'of the lower end and the four horizontal annular protrusions 241 of the impeller wear ring 240 and the lower annular recess R' A micro annular chamber C and one additional micro annular chamber C 'formed in layers by the engagement of the extensions ext having a step on the lower surface of the horizontal annular recess r; The present invention is not limited to this but the present invention is not limited thereto and one annular recess R of the casing wear ring 230 and one horizontal annular protrusion 241 of the impeller wear ring 240 The object of the present invention can also be achieved by the micro annular chamber C having a U-shaped cross section.

In addition, the lower end of the horizontal annular concave portion r of the impeller wear ring 240 in the rectangular additional annular chamber C 'may be formed in the middle of the extension portion ext of the lower surface, May not be provided.

Further, the inner end face of the annular concave portion R of the casing wear ring 230 and the horizontal annular concave portion r of the impeller wear ring 240 may be triangular, polygonal or circular, or may be formed at right angles, acute angles, or obtuse angles to the flat sides .

The main parts of another embodiment of the present invention are shown in Figs. 8A and 8B. 8A is a structure in which the space X of the casing wear ring 230 is omitted in the embodiment of the present invention shown in FIG. 7B.

The embodiment shown in FIG. 8B is a structure in which the additional micro-annular chamber C 'is replaced with a micro-annular chamber having a C-shaped cross section at the upper end thereof in the embodiment of the present invention shown in FIG. 7B.

 It goes without saying that other modifications of the annular projection of the wear ring can be used depending on the performance, specification and size of the centrifugal pump.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It is possible. Accordingly, the spirit of the present invention should be understood only by the appended claims, and all equivalent or equivalent variations thereof are included in the scope of the present invention.

100: casing
140: Casing cover
200: Impeller
230: casing wear ring
240: Impeller Wearing
241: Horizontal annular projection
C: Micro-annular chamber
C ': additional micro-annular chamber
R: annular concave
R ': additional annular recess
r: Horizontal annular recess
r ': additional horizontal annular recess

Claims (7)

A centrifugal pump comprising a casing (100) and an impeller (200) rotating inside the casing (100)
A casing wear ring (230) mounted on the inner surface of the casing (100) and having an annular recess (R) whose upper inner surface is short and the lower inner surface is inclined downward to the right;
Wherein the upper surface has one horizontal annular protrusion (241) which is in close contact with the end of the upper inner surface of the annular recess (R) of the casing wear ring (230) and protrudes into the annular recess (R) An impeller ware ring 240 in which the lower surface of the horizontal annular recess r formed in the lower portion of the projection 241 is in close contact with the end of the lower inner surface of the annular recess R of the casing wear ring 230;
A micro annular chamber C formed by combining an annular recess of the casing wear ring 230 and a horizontal annular protrusion of the impeller wear ring 240; Wherein the leakage loss between the casing and the impeller is reduced. The method according to claim 1,
The casing wear ring 230 further comprises one additional annular recess R 'formed in the lower portion thereof with the annular recess R,
A further annular recess R 'of the casing wear ring 230 is closed by an extension of the lower surface of the horizontal annular recess r of the impeller wear ring 240 to form a quadrangular additional annular chamber C' Wherein the leakage loss between the casing and the impeller is reduced. 3. The method of claim 2,
Characterized in that an extension of the lower surface of the horizontal annular recess (r) of the impeller wear ring (240) in the tetragonal additional annular chamber (C ') has an intermediate downward or upward step. Centrifugal pump with reduced leakage loss between impellers. The method according to claim 1,
The casing wear ring 230 has two or more annular recesses R formed in layers,
The impeller wear ring 240 is provided with a number of layered horizontal annular protrusions 241 corresponding to the annular recess R of the casing wear ring 230,
(C) of the same number as the annular concave portion (R) of the casing wear ring (230). 5. The method of claim 4,
The casing wear ring 230 further comprises one additional annular recess R 'formed in the lower portion thereof with the annular recess R at the lower end thereof,
The additional annular recess R 'of the casing wear ring 230 is closed by the extension of the lower surface of the horizontal annular recess r at the lower end of the impeller wear ring 240 to form a rectangular additional annular chamber C ') is formed between the casing and the impeller, wherein the leakage loss between the casing and the impeller is reduced. 6. The method of claim 5,
Characterized in that an extension of the lower surface of the horizontal annular recess (r) of the impeller wear ring (240) in the tetragonal additional annular chamber (C ') has an intermediate downward or upward step. Centrifugal pump with reduced leakage loss between impellers. 7. The method according to any one of claims 1 to 6,
The annular concave portion R of the casing wear ring 230 and the inner annular concave portion r of the impeller wear ring 240 are formed into a triangular shape, a polygonal shape or a circular shape, or formed at right angle, acute angle or obtuse angle Wherein the leakage loss between the casing and the impeller is reduced.

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