AU2018281248B2

AU2018281248B2 - Centrifugal slurry pump and impeller

Info

Publication number: AU2018281248B2
Application number: AU2018281248A
Authority: AU
Inventors: Jae Woong Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-06-08
Filing date: 2018-06-07
Publication date: 2021-08-12
Anticipated expiration: 2038-06-07
Also published as: AU2018281248A1; WO2018226035A1; KR101826819B1

Abstract

The present invention relates to a centrifugal slurry pump for pumping a fluid in the form of a slurry, and an impeller. The centrifugal slurry pump comprises: a case having a receiving space formed therein, a case inlet formed at one side thereof, and a case outlet formed at the other side thereof; and an impeller, installed in the receiving space of the case so as to be rotated by means of a motor, having a central inlet formed on one side thereof so as to suck the slurry through the case inlet, and having at least one vane formed thereinside so as to forcibly discharge the slurry in the direction of the case outlet by centrifugal force, wherein an impeller-side annular sealing surface adjacent to the central inlet of the impeller may be formed to be inclined at a first angle that is an obtuse angle, with respect to the axis of rotation, opposite to the flow direction of the fluid, and a case-side annular sealing surface adjacent to the case inlet of the case may be formed at least partially in parallel with the impeller-side annular sealing surface.

Description

CENTRIFUGAL SLURRY PUMP AND IMPELLER TECHNICAL FIELD

[0001] The present disclosure relates to a centrifugal slurry pump and an impeller, and

more particularly, to a centrifugal slurry pump for pumping a fluid in the form of a slurry and

an impeller.

BACKGROUND

[0002] In general, a centrifugal pump is a device for rotating a fluid by using an impeller

installed in a case and pumping the fluid using a centrifugal force. The impeller includes a

plurality of wings having a radial vortex shape to transfer a material having a relatively low

density such as water. However, when a fluid having an extremely high density such as oil,

wastewater slurry, suspension, concentrate, or a mixture thereof is transferred, a low pressure

area is generated between the case that is a fixed body and the impeller that is a rotation body,

this low pressure area inevitably causes moisture contained in a slurry to evaporate, thereby

generating bubbles or pores, and when a large amount of bubbles or pores is generated, the

impeller runs idle to remarkably reduce a transfer efficiency and furthermore generate an

explosion phenomenon, in which the bubbles or the pores are exploded in the centrifugal pump

while boundary surfaces between the bubbles or the pores are collapsed. Thus, the inside of

the centrifugal pump may be seriously damaged, wear between components may be caused, or

durability of all sorts of components such as the case and the impeller may be deteriorated.

[0003] As illustrated in FIG. 7, a typical centrifugal slurry pump disclosed in Korean

Registered Patent No. 10-0225027 is formed such that a case-side annular sealing surface Fl

is formed in a case, and an impeller-side annular sealing surface F2 is formed in an impeller.

Each of the case-side annular sealing surface F1 and the impeller-side annular sealing surface

F2 is inclined at a second angle Q, which is an acute angle less than 900, with respect to a

rotation axis line opposite to a fluid flow.

[0004] The typical centrifugal slurry pump is invented to hide the impeller-side annular

sealing surface F2 from the fluid flow because of a main fluid flow VI and V2 to minimize

mechanical friction of the impeller by using the sealing surfaces F1 and F2 inclined in a

direction in which the fluid flow between the case-side annular sealing surface F1 and the

impeller-side annular sealing surface F2 is combined with the main fluid flow VI and V2 as

expressed by a dotted arrow line.

[0005] However, although the typical centrifugal slurry pump may reduce the mechanical

friction of the impeller, the fluid flow V2 at a rotating impeller side has a velocity greaterthan

that of the fluid flow VI at a fixed case side as illustrated in FIG. 7, the flow between the case

side annular sealing surface F1 and the impeller-side annular sealing surface F2 accelerates the

fluid flow V2 at the impeller side to generate a low pressure area at a portion A as expressed

by a dotted arrow line, and as the generated low pressure area generates bubbles or pores, an

explosion phenomenon, in which the bubbles or the pores are exploded in the centrifugal slurry

pump while boundary surfaces between the bubbles or the pores are collapsed according to the

atmospheric pressure, is seriously generated. Thus, the inside of the centrifugal pump may

be seriously damaged, wear between components may be caused, or durability of all sorts of

components such as the case and the impeller may be deteriorated.

[0006] In addition, since the impeller and the case are deteriorated in durability, the

impeller may be frequently replaced, the case may include the more number of components

because an outer case made of a metal material and a replaceable inner case made of a rubber material, which is installed inside the outer case, are separately installed, manufacturing costs increase due to the complex structure, and operation costs and management costs increase due to the component replacement.

[0006A] Any discussion of documents, acts, materials, devices, articles or the like which

has been included in the present specification is not to be taken as an admission that any or all

of these matters form part of the prior art base or were common general knowledge in the

field relevant to the present disclosure as it existed before the priority date of each of the

appended claims.

[0006B] Throughout this specification the word "comprise", or variations such as

"comprises" or "comprising", will be understood to imply the inclusion of a stated element,

integer or step, or group of elements, integers or steps, but not the exclusion of any other

element, integer or step, or group of elements, integers or steps.

SUMMARY

[0006C] It is desired to address one or more shortcomings associated with prior

centrifugal slurry pumps and impellers, or to at least provide a useful alternative thereto.

[0007] Thus, some embodiments of the present disclosure may relate to providing a

centrifugal slurry pump and an impeller, which are capable of: preventing the generation of

bubbles or pores by forming the case-side annular sealing surface and the impeller-side

annular sealing surface at a first angle that is an obtuse angle greater than 90 with respect to

the rotation axis line opposite to the fluid flow to prevent the generation of the low pressure

area; preventing the centrifugal slurry pump from being damaged, worn, or deteriorated in

durability due to the explosion phenomenon of the bubble or pores; maximizing a pumping

efficiency with an optimized condition according to the kind of a slurry, a specification, and

an operation environment by precisely controlling the fluid flow between the case-side annular

sealing surface and impeller- side annular sealing surface using a stepped portion; and saving the manufacturing costs, the operations costs, and management costs of a product by using a single case. However, this technical feature is merely an example, and thus the scope of the present disclosure is not limited thereto.

[0007A] Some embodiments relate to a centrifugal slurry pump comprising:

a case having a receiving space formed therein and comprising a case inlet formed at

one side thereof and a case outlet formed at the other side thereof; and

an impeller installed in the receiving space of the case so as to be rotated by means of a

motor and comprising a central inlet formed at one side thereof so as to suck a slurry through

the case inlet and at least one vane formed therein so as to forcibly discharge the slurry in a

direction of the case outlet by using a centrifugal force,

wherein an impeller-side annular sealing surface adjacent to the central inlet of the

impeller is inclined at a first angle that is an obtuse angle with respect to a rotation axis line

opposite to a flow direction of a fluid, and a case-side annular sealing surface adjacent to the

case inlet of the case is at least partially in parallel with the impeller-side annular sealing

surface, and

wherein the case inlet has a diameter (D1) smaller than a diameter (D2) of the central

inlet to generate a stepped portion (T) between the case inlet and the central inlet.

[0008] Embodiments of the present disclosure provide a centrifugal slurry pump including:

a case having a receiving space formed therein and including a case inlet formed at one side

thereof and a case outlet formed at the other side thereof; and an impeller installed in the

receiving space of the case so as to be rotated by means of a motor and including a central inlet

formed at one side thereof so as to suck a slurry through the case inlet and at least one vane

formed therein so as to forcibly discharge the slurry in a direction of the case outlet by using a

centrifugal force. Here, an impeller-side annular sealing surface adjacent to the central inlet

of the impeller is inclined at a first angle that is an obtuse angle with respect to a rotation axis

line opposite to a flow direction of a fluid, and a case-side annular sealing surface adjacent to the case inlet of the case is at least partially in parallel with the impeller-side annular sealing surface.

[0009] According to some embodiments of the present disclosure, the first angle may

range from 1000 to 135°.

[0010] According to some embodiments of the present disclosure, a flat portion of the

impeller-side annular sealing surface may have a width W that is 5% to 25% of a diameter

D2 of the central inlet.

[0011] According to some embodiments of the present disclosure, the impeller may

include a vane having a radial vortex shape in a circumferential direction from the central inlet

at the inside thereof, the vane may form a passage cross-section having a circular or oval

shape, through which the fluid passes, and the passage cross-section may have an area that

gradually increases in a circumferential direction from a center thereof.

[0012] According to some embodiments of the present disclosure, the case maybe a metal

integrated case having an outer surface contacting the air and an inner surface corresponding

to the impeller.

[0013] According to some embodiments of the present disclosure, the centrifugal slurry

pump may further include an impeller forward and backward movement device configured to

move the impeller forward and backward so as to adjust a gap S between the impeller-side

annular sealing surface of the impeller and the case-side annular sealing surface of the case.

[0014] According to some embodiments of the present disclosure, the case inlet may have an

inner diameter D1 that is smaller than an inner diameter D2 of the central inlet to generate a

stepped portion T between the case inlet and the central inlet.

[0015] In some embodiments of the present disclosure, an impeller includes: a central inlet

formed at one side thereof; and at least one vane formed therein so as to forcibly discharge a

slurry in a direction of a case outlet by using a centrifugal force. Here, an impeller-side

annular sealing surface adjacent to the central inlet protrudes while being inclined at a first

angle that is an obtuse angle with respect to a rotation axis line opposite to a flow direction of a fluid.

[0016] According to some embodiments of the present disclosure, the vane may have a

radial vortex shape in a circumferential direction from the central inlet at the inside thereof, a

passage cross-section, through which the fluid passes, may have a circular or oval shape, and

the passage cross-section may have an area that gradually increases in a circumferential

direction from a center thereof.

[0017] As described above, according to some embodiments of the present disclosure, the

generation of bubbles or pores may be prevented by preventing the generation of the low

pressure area, through this, the centrifugal slurry pump may be prevented from being damaged,

wom, or deteriorated in durability caused by the explosion phenomenon of the bubbles or

pores, the pumping efficiency may be maximized with the optimized condition according to

the kind of the slurry, the specification of the pump, and the operation environment by

precisely controlling the fluid flow between the case-side annular sealing surface and

impeller-side annular sealing surface using the stepped portion, and the manufacturing costs,

the operations costs, and management costs of the product may be saved by using the single

case. Also, the scope of the present disclosure is not limited to the above-described effects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a front perspective view illustrating a centrifugal slurry pump according

to some embodiments of the present disclosure.

[0019] FIG. 2 is a rear perspective view illustrating the centrifugal slurry pump of FIG. 1.

[0020] FIG. 3 is an exploded perspective view illustrating components of the centrifugal

slurry pump of FIG. 1.

[0021] FIG. 4 is a cross-sectional view illustrating a portion of the centrifugal slurry pump

of FIG. 1.

[0022] FIG. 5 is an enlarged cross-sectional view illustrating a portion B of the centrifugal slurry pump of FIG. 4.

[0023] FIG. 6 is an enlarged cross-sectional view illustrating the centrifugal slurry pump

according to other embodiments of the present disclosure.

[0024] FIG. 7 is an enlarged cross-sectional view illustrating a typical centrifugal slurry

pump.

[0025] FIG. 8 is a front perspective view illustrating an impeller according to some

embodiments of the present disclosure.

[0026] FIG. 9 is a rear perspective view illustrating the impeller of FIG. 8.

[0027] FIG. 10 is a front cross-sectional view illustrating the impeller of FIG. 8.

[0028] FIG. 11 is a side cross-sectional view illustrating the impeller of FIG. 8.

DETAILED DESCRIPTION

[0029] Hereinafter, specific embodiments will be described in detail with reference to the

accompanying drawings.

[0030] The present disclosure may, however, be embodied in many different forms and

should not be construed as being limited to the embodiments set forth herein; rather, these

embodiments are provided so that those skilled in the art thoroughly understand the present

disclosure. Rather, these embodiments are provided so that this disclosure will be thorough

and complete, and will fully convey the scope of the present disclosure to those skilled in the

art. Also, in the figures, a thickness or dimension of each of layers is exaggerated for clarity

of illustration.

[0031] It will be understood that it is referred to as being "on," connected to", "stacked", or "coupled to" another element, it may be directly on, connected, stacked, or coupled to the

other element or intervening elements may be present. In contrast, when an element is

referred to as being "directly on," "directly connected to" or "directly coupled to" another

element or layer, there are no intervening elements or layers present. Like reference numerals

refer to like elements throughout. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[0032] As used herein, terms such as "first," "second," etc. are used to describe various

members, components, regions, layers, and/or portions. However, it is obvious that the

members, components, regions, layers, and/or portions should not be defined by these terms.

The terms do not mean a particular order, up and down, or superiority, and are used only for

distinguishing one member, component, region, layer, or portion from another member,

component, region, layer, or portion. Thus, a first member, component, region, layer, or

portion which will be described may also refer to a second member, component, region, layer,

or portion, without departing from the teaching of the present disclosure.

[0033] Spatially relative terms, such as "above" or "upper" and "below" or "lower" and

the like, may be used herein for ease of description to describe one element or feature's

relationship to another element(s) or feature(s) as illustrated in the figures. It will be

understood that the spatially relative terms are intended to encompass different orientations of

the device in use or operation in addition to the orientation depicted in the figures. For

example, if the device in the figures is turned over, elements described as "below" other

elements or features would then be oriented "above" the other elements or features. Thus, the

exemplary term "above" may encompass both an orientation of above and below. The device

may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative

descriptors used herein interpreted accordingly.

[0034] The terms used herein are for illustrative purposes of the present disclosure only and should not be construed to limit the meaning or the scope of the present disclosure. As used in this specification, a singular form may, unless definitely indicating a particular case in terms of the context, include a plural form. The meaning of 'comprises' and/or 'comprising' specifies a property, a region, a fixed number, a step, a process, an element and/or a component but does not exclude other properties, regions, fixed numbers, steps, processes, elements and/or components.

[0035] Additionally, the embodiment in the detailed description will be described with

sectional views as ideal exemplary views of the inventive concept. In the drawings, for

example, according to the manufacturing technology and/or tolerance, the modification of the

illustrated shape may be expected. Thus, the exemplary embodiments of the present

disclosure must not be interpreted to be limited by a particular shape that is illustrated in the

drawings and must include a change in the shape occurring, for example, during manufacturing.

[0036] FIG. 1 is a front perspective view illustrating a centrifugal slurry pump 100

according to some embodiments of the present disclosure, FIG. 2 is a rear perspective view

illustrating the centrifugal slurry pump 100 of FIG. 1, FIG. 3 is an exploded perspective view

illustrating components of the centrifugal slurry pump 100 of FIG. 1, FIG. 4 is a cross-sectional

view illustrating a portion of the centrifugal slurry pump 100 of FIG. 1, and FIG. 5 is an

enlarged cross-sectional view illustrating a portion B of the centrifugal slurry pump 100 of FIG.

4.

[0037] As illustrated in FIGS. 1 to 5, the centrifugal slurry pump 100 according to some

embodiments of the present disclosure may include a frame 10, a case 20, and an impeller 30.

[0038] For example, as illustrated in FIGS. I to 5, the frame 10 maybe a structure installed

on the ground to support a load of the case 20 and the impeller and having a sufficient strength

and durability so as to sustain a mechanical stress during operation. For example, the frame

10 maybe an assembly structure made of a metallic material or the like, which is formed by assembling all sorts of horizontal members, vertical members, and various shaped block members through a coupling hole.

[0039] However, the embodiment is not limited to the shape of the frame in the drawing.

For example, the frame 10 may include all sorts of frame structures capable of supporting the

case 20 and the impeller 30.

[0040] Also, for example, as illustrated in FIGS. 1 to 5, the case 20 may be a container

structure that is fixed to one side of the frame 10, has a receiving space formed therein to

receive the impeller 30, and includes a case inlet 20a formed at one side thereof and a case

outlet 20b formed at the other side thereof.

[0041] More particularly, for example, the case 20 may be a metal integrated case having

an outer surface contacting the air and an inner surface corresponding to the impeller 30.

[0042] The above-described case 20 may reduce a wear rate of a component by reducing

typical bubbles or pores from being generated due to an angle of an annular sealing surface,

which will be described later, and, through this, remarkably save management costs or

operation costs of a pump because components are unnecessary to be replaced and thus a

replaceable inner case is unnecessary.

[0043] Also, for example, as illustrated in FIGS. 1 to 5, the impeller 30 is installed in the

receiving space of the case 20 so as to be rotated by means of a motor M installed to the frame

10. The impeller 30 may be a kind of rotary wing structure including a central inlet 30a

formed at one side thereof so as to suck a slurry through the case inlet 20a and at least one vane

30b formed therein so as to forcibly discharge the slurry in a direction of the case outlet 20b by

using a centrifugal force.

[0044] Here, as illustrated in FIGS. 4 and 5, in the impeller 30, an impeller-side annular

sealing surface F2 adjacent to the central inlet 30a of the impeller 30 may be formed, and a

case-side annular sealing surface F1 adjacent to the case inlet 20a may be formed to face the impeller-side annular sealing surface F2.

[0045] The impeller-side annular sealing surface F2 may be inclined at a first angle K that

is an obtuse angle with respect to a rotation axis line L opposite to a flow direction of a fluid,

and the case-side annular sealing surface F1 may be formed at least partially in parallel with

the impeller-side annular sealing surface F2 and inclined at an angle that is almost equal to the

first angle K.

[0046] Here, the first angle K may be an obtuse angle greater than 90. As a result of

repeated simulations and experiments, the first angle K, at which bubbles or pores due to a low

pressure area are minimally generated, may be 1000 to 135°.

[0047] That is, since component manufacturing or assembling is inconvenient when the

first angle K is too large, and an effect of bubble or pore generation is reduced when the first

angle K is too small, an appropriate value may be selected and applied.

[0048] Thus, as illustrated in FIG. 5, the first angle K is a feature of being inclined in a

direction branched and escaped between the case-side annular sealing surface F1 and impeller

side annular sealing surface F2 as a main flow of a fluid is expressed by a dotted arrow line.

When a gap S between the impeller-side annular sealing surface F2 of the impeller 30 and the

case-side annular sealing surface F1 of the case 20 is minimized, the low pressure area may be

minimally formed on the basis of theoretical and experimental results.

[0049] Here, by using an impeller forward and backward movement device 40, the gap S

between the impeller-side annular sealing surface F2 of the impeller 30 and the case-side

annular sealing surface Fl of the case 20 may be minimized, generation of bubbles and pores

may be prevented by preventing generation of the low pressure area, and the centrifugal slurry

pump may be prevented from being damaged, worn, and deteriorated in durability due to a

explosion phenomenon of the bubbles or pores.

[0050] Also, when the gap S between the impeller-side annular sealing surface F2 of the impeller 30 and the case-side annular sealing surface Fl of the case 20 is minimized, sealing between the case 20 and the impeller 30 may be improved to enhance an efficiency of a pump.

In this case, a flat portion of the impeller-side annular sealing surface F2 may have a width W

that is 5% to 25% of an inner diameter D2 of the central inlet 30a for sufficient sealing on the

basis of the repeated experiments and simulations.

[0051] However, the embodiment is not limited to the above-described values. For

example, the sealing surface may have extremely various ratios of width to diameter according

to the kind of the slurry, a specification of the pump, an operation environment or condition,

etc.

[0052] Also, for example, as illustrated in FIGS. 1 to 4, the impeller forward and backward

movement device 40 may move the impeller forward and backward so as to adjust the gap S

annular sealing surface Fl of the case 20. Thus, the impeller forward and backward

movement device 40 may include extremely various types of devices capable of moving the

impeller 30.

[0053] For example, as illustrated in FIGS. 1 and 2, after the frame 10 is installed, a

forward and backward movement adjusting screw capable of pressing the impeller 30 or the

like may be installed. However, the embodiment is not limited to the drawing. For example,

a screw rod or a guide rod that is automatically adjusted in forward and backward movement

positions by a motor.

[0054] Besides, various shapes of position adjusting screws capable of constantly

maintaining a rotation path of the impeller 30 may be additionally installed to prevent the

impeller 30 from being vibrated during rotation of the impeller 30.

[0055] FIG. 6 is an enlarged cross-sectional view illustrating the centrifugal slurry pump

100 according to other embodiments of the present disclosure.

[0056] As illustrated in FIG. 6, the centrifugal slurry pump 100 according to other

embodiments of the present disclosure is formed such that the case inlet 20a has an inner

diameter D1 smaller than the inner diameter D2 of the central inlet 30a to generate a stepped

portion T between the case inlet 20a and the central inlet 30a.

[0057] Thus, as a main flow of the fluid is expressed by a dotted arrow line by the stepped

portion T, a branched amount, which is branched between the impeller-side annular sealing

surface F2 of the impeller 30 and the case-side annular sealing surface Fl of the case 20, may

be minimized.

[0058] That is, when the stepped portion T is not provided, there is a high possibility that

the main flow is branched between the impeller-side annular sealing surface F2 of the impeller

30 and the case-side annular sealing surface Fl of the case 20. However, when the stepped

portion T is provided, an entrance between the impeller-side annular sealing surface F2 and the

case-side annular sealing surface F1 is hidden by the case-side annular sealing surface F1,

which relatively protrudes, to minimize the main flow from being introduced between the

impeller-side annular sealing surface F2 and the case-side annular sealing surface F1.

[0059] However, since a low pressure area may be generated when the stepped portion T

is too large, an optimum design may be required for the stepped portion T according to the kind

of the slurry, the specification of the pump, the operation environment, etc.

[0060] That is, as the flow of the fluid between the impeller-side annular sealing surface

F2 and the case-side annular sealing surface F1 is precisely controlled by using the stepped

portion T, a pumping efficiency may be maximized with an optimized condition according to

the kind of the slurry, the specification of the pump, and the operation environment.

[0061] FIG. 8 is a front perspective view illustrating the impeller 30 according to some

embodiments of the present disclosure, FIG. 9 is a rear perspective view illustrating the

impeller of FIG. 8, FIG. 10 is a front cross-sectional view illustrating the impeller of FIG. 8,

and FIG. 11 is a side cross-sectional view illustrating the impeller of FIG. 8.

[0062] For example, as illustrated in FIGS. 3 to 11, the impeller 30 may include the vane

30b having a radial vortex shape in a circumferential direction from the central inlet 30a at the

inside thereof, the vane 30b may form a passage cross-section Al and A2 having a circular or

oval shape, through which the fluid passes, and the passage cross-section Al and A2 may have

an area that gradually increases in a circumferential direction from a center thereof.

[0063] Thus, since the passage cross-section Al and A2, through which the fluid passes,

has a circular or oval shape, an angled corner at the inside, which causes energy loss, may be

minimized to maximize the efficiency of the impeller 30.

[0064] The present disclosure includes the above-described centrifugal slurry pump 100

and the impeller 30 applied thereto. As illustrated in FIGS. 3 to 11, the impeller according to

some embodiments of the present disclosure includes the central inlet 30a formed at one side

thereof, at least one vane 30b formed therein so as to forcibly discharge the slurry in a direction

of the case outlet 20b by using a centrifugal force, and the impeller-side annular sealing surface

F2 protruding while being inclined at the first angle K that is an obtuse angle with respect to

the rotation axis line L opposite to the flow direction of the fluid.

[0065] Here, the vane 30b may have the radial vortex shape in the circumferential direction

from the inner central inlet 30a, the passage cross-section Al and A2, through which the fluid

passes, may have a circular or oval shape, and the passage cross-section Al and A2 may have

an area that gradually increases in the circumferential direction from the center thereof.

[0066] Thus, according to the centrifugal slurry pump 100 and the impeller 30 of the

present disclosure, the generation of bubbles or pores may be prevented by preventing the

generation of the low pressure area, through this, the centrifugal slurry pump may be prevented

from being damaged, worn, or deteriorated in durability due to the explosion phenomenon of

the bubbles or pores, the pumping efficiency may be maximized with an optimized condition according to the kind of the slurry, the specification of the pump, and the operation environment by precisely controlling the fluid flow between the case-side annular sealing surface and impeller-side annular sealing surface using the stepped portion, and the manufacturing costs, the operations costs, and management costs of the product may be saved by using the single case.

[0067] Although the exemplary embodiments of the present disclosure have been described,

it is understood that the present disclosure should not be limited to these exemplary

embodiments but various changes and modifications can be made by one ordinary skilled in

the art within the spirit and scope of the present disclosure as hereinafter claimed. Hence, the

real protective scope of the present disclosure shall be determined by the technical scope of

the accompanying claims.

[0068] As described above, according to some embodiments of the present disclosure, the

wom, or deteriorated in durability due to the explosion phenomenon of the bubbles or pores,

the pumping efficiency may be maximized with an optimized condition according to the kind

of the slurry, the specification of the pump, and the operation environment by precisely

controlling the fluid flow between the case-side annular sealing surface and impeller-side

annular sealing surface using the stepped portion, and the manufacturing costs, the operations

costs, and management costs of the product may be saved by using the single case.

Claims

1. A centrifugal slurry pump comprising:

one side thereof and a case outlet formed at the other side thereof; and

an impeller installed in the receiving space of the case so as to be rotated by means of

a motor and comprising a central inlet formed at one side thereof so as to suck a slurry through

direction of the case outlet by using a centrifugal force,

case inlet of the case is at least partially in parallel with the impeller-side annular sealing surface,

and

2. The centrifugal slurry pump of claim 1, wherein the first angle ranges from

1000 to 135°.

3. The centrifugal slurry pump of claim 1 or claim 2, wherein a flat portion of

the impeller- side annular sealing surface has a width (W) that is 5% to 25% of a diameter (D2)

of the central inlet.

4. The centrifugal slurry pump of any one of claims 1 to 3, wherein the impeller

comprises a vane having a radial vortex shape in a circumferential direction from the central

inlet at the inside thereof, the vane forms a passage cross-section having a circular or oval

shape, through which the fluid passes, and the passage cross-section has an area that

gradually increases in a circumferential direction from a center thereof.

5. The centrifugal slurry pump of any one of claims 1 to 4, wherein the case is a

metal integrated case having an outer surface contacting the air and an inner surface

corresponding to the impeller.

6. The centrifugal slurry pump of any one of claims 1 to 5, further comprising

an impeller forward and backward movement device configured to move the impeller forward

and backward so as to adjust a gap (S) between the impeller-side annular sealing surface of

the impeller and the case-side annular sealing surface of the case.