CN220979932U - Pump cavity of split pump - Google Patents

Abstract

The utility model discloses a pump cavity of a split pump, which is formed by enclosing a pump body and a pump cover to form a cavity structure, wherein a driving side mechanical seal chamber, a first-stage suction chamber, an inducer chamber, a plurality of positive impeller chambers, an impeller pressure release chamber, a plurality of counter impeller chambers, a secondary suction chamber and a high-pressure side mechanical seal chamber are sequentially arranged along a driving end to a high-pressure end; the inlet of the pump cavity, the first-stage suction chamber, the inducer chamber and the plurality of positive impeller chambers are sequentially communicated; the final stage positive impeller chamber is communicated with the secondary suction chamber through a transition channel; the secondary suction chamber, the plurality of impeller reversing chambers are sequentially communicated with the outlet of the pump cavity; the impeller pressure release chamber is communicated with the penultimate positive impeller chamber through a pressure release pipeline. The utility model can eliminate the axial force generated by the impeller in the running process and the radial force generated by the high-low pressure liquid in the impeller cavity to the impeller in the running process, thereby eliminating the axial stress vibration and the radial stress vibration of the rotor assembly, ensuring the stable and reliable running of the pump and prolonging the running and service life of the pump.

Description

Pump cavity of split pump

Technical Field

The utility model belongs to the technical field of pumps, and particularly relates to a pump cavity of a split pump.

Background

The split pump is a special centrifugal pump with more impeller stages and extremely high pump lift, the flow rate of the pump reaches 5000m3/h or more, the pump lift reaches 4000m or more, the rotating speed of the pump reaches 3000 r/min-10000 r/min, and the matched power of the pump reaches 20000Kw or more; the method is applied to special heavy station industries such as a large station sea water desalination project, a large station coal exploitation project, a large station oilfield water injection project, a large station petroleum long-distance conveying project, a high-pressure pipeline conveying process of a refinery, a high-pressure water supply project of a power plant boiler, an LNG low-temperature high-pressure liquid conveying project, a high-pressure dephosphorization system of a steel plant and the like, and cannot be replaced by a general split centrifugal pump and a multistage centrifugal pump, so that the stability, the reliability and the safety of the use and the operation of the multistage split pump are very important; because of the special application field of the pump, the design development, production and manufacture, use and maintenance, and part exchange capability of the multistage split pump are also very important, namely the long full life cycle of the pump is very important.

In the spiral volute type pumping chamber, when the flow mutual coordination condition of the pumping chamber and the impeller is destroyed, namely, the working condition flow of the pump is smaller or larger than the design rated flow due to certain reasons (such as pressure change of working condition of a pipe network system, change of required flow of the tail end of a device system, change of frequency of a power grid system, change of lift of a pump inlet pipeline system, stalling or overspeed of a pump driving machine system and the like), the sharp contradiction between the operating condition flow and the design rated flow occurs, the condition that the pressure in the spiral volute type pumping chamber is symmetrically distributed along the axis of the impeller is destroyed, the high-pressure and low-pressure liquid pressure in the spiral volute type pumping chamber acts on the blades and the excircle of the impeller, so that radial force is generated, the radial force is transmitted to the pump shaft through the impeller, the pump shaft is subjected to alternating stress, and directional disturbance is generated, the radial force is transmitted to the bearing box, the pump body and the pump cover through the pump shaft, so that the rotor vibration of the pump is large, the bearing vibration is large, the pump body is damaged, the parts such as to damage the pump shaft, the mechanical seal, the impeller and the whole service life of the pump is shortened. In the prior art, the impeller pumping chamber of the split pump is of a single-channel spiral volute pumping chamber or double-channel spiral volute pumping chamber structure, the radial force of a pump rotor cannot be eliminated by the single-channel spiral volute pumping chamber, most of the radial force cannot be eliminated by the double-channel spiral volute pumping chamber, the radial force generated by the split pump is large because of the large number of impeller stages, the number of the inter-stage pumping chambers and the number of inter-stage suction chambers of the impeller are large because of the large number of impeller stages, and the pump body and the pump cover have errors when in casting so that the size of the channels of the pumping chamber and the suction chamber deviate from the design shape value, the radial force acted on the pump shaft is alternated for a plurality of times, the pump shaft bears a plurality of bending stresses and a plurality of alternating shearing stresses, the pump shaft is subjected to irregular disturbance and deformation, the rotating assembly and the non-rotating assembly of the pump are rubbed by the forces and the deformation to damage and cause vibration of the pump, the friction vibration can cause the pump to generate larger noise during operation and seriously affect the working environment, meanwhile, the pump set is subjected to serious vibration and shake, each bolt or connection of the pump and the pump set is loosened to cause leakage of conveying media or serious damage of the pump set to cause serious accidents, multiple friction stresses are generated due to friction between rotating parts and non-rotating parts of the pump, and the forces are superposed with radial forces of a pump rotor on the pump shaft again to enable the pump shaft to bear larger repeated bending stresses and multiple alternating shearing stresses, so that the pump shaft is damaged.

The radial area of the front cover plate of the impeller is smaller than that of the rear cover plate of the impeller due to the suction inlet of the impeller, the radial area is just the radial area of the suction inlet of the impeller, and the pressure of the suction inlet of the impeller is smaller than that of the rear cover plate of the impeller when the pump operates, so that the pump generates axial force when in operation; the split pump adopts a plurality of impellers connected in series to enable the impeller lifts to be overlapped to realize high lifts. In the prior art, due to the fact that the pump uses working condition parameters, the problem of asymmetric distribution exists in the mounting arrangement of the impeller of the pump on the pump shaft, so that axial force is generated by the impeller in the operation process of the pump, meanwhile, due to the special structural form of the split pump, the impeller cavities of the final-stage positive impeller and the final-stage secondary counter impeller form huge pressure difference, the two impeller cavities are directly communicated through a hub fit clearance, and because the hub fit clearance is incomplete in blocking and depressurizing the pressure difference liquid, the final-stage positive impeller and the final-stage counter impeller generate huge axial force, sometimes the axial force can reach tens of tons or more, the axial force acts on the final-stage positive impeller, the pump rotor generates axial movement, at the moment, a sliding thrust disc mechanism is required to bear the axial force, the pump shaft bears huge axial tensile stress, and the sliding thrust disc bears heavy-load high-speed rotation friction for a long time, and the sliding thrust disc mechanism is easy to generate heat, wear and damage, the complicated cost is high, the overhaul and maintenance process is complicated, when the working condition pressure of the pump fluctuates and changes due to certain reasons (the working condition pressure of a pipe network system, the required flow rate of a device system tail end, the frequency of a power grid system, the lift of a pump inlet pipeline system device, the stall or overspeed of a pump driving machine system and the like), the axial force also fluctuates and changes, so that the rotor of the pump moves left and right dynamically to cause friction of the sliding thrust disc, the rotor generates disc-shaped jolt vibration to cause serious increase of the vibration of the pump, the pump shaft bears axial tensile stress and compressive stress, the bearing, the shaft sleeve and the like of the pump are damaged by friction, the sliding thrust disc generates axial sintering and seizing to cause the shaft breakage accident of the main shaft when the friction is serious, the left and right movement of the pump rotor can cause the sealing compression ratio of the mechanical seal to change, leakage occurs when the compression ratio is small, and the seal is burned and damaged due to serious friction when the compression ratio is large.

In the prior art, an inter-stage impeller pumping chamber, an inter-stage impeller suction chamber and a final stage secondary positive impeller pumping chamber of the multistage split pump are of single-channel spiral volute type or double-channel spiral volute type structures, no volute guide vanes are arranged in the pumping chamber and the suction chamber, when the impeller rotates at a high speed in the pumping chamber and the suction chamber to convert mechanical energy into pressure energy to perform water force action, pressure fluctuation and pressure vortex can occur in the pressure in the volute type flow passage due to unbalanced cross section area and shape of the spiral volute type flow passage and no volute guide vanes, the pressure fluctuation and the pressure vortex can eliminate and balance the pressure fluctuation and the pressure vortex due to the lack of the volute guide vanes, the fluctuation excitation and the vortex excitation can be caused by the pressure fluctuation and the pressure vortex excitation, the vibration is transmitted to a feed pump through a main shaft, operation noise of the pump is increased and the vibration is increased, meanwhile, the pressure fluctuation and the pressure vortex excitation can cause high-low pressure difference to occur in the pumping chamber and the suction chamber, the inter-stage cavitation can occur in each impeller, the inter-stage cavitation can generate bubbles to block the flow passage and the impeller flow passage of the pump, the impeller cannot be sufficiently converted into effective energy, the radial vibration energy is further, the radial vibration of the pump is further, the radial vibration is generated, and the radial vibration noise of the pump is further generated, and the radial vibration noise is further generated.

In summary, during operation of the pump, axial force and radial force are continuously and alternately superposed on the pump shaft, so that the pump shaft is subjected to great axial tensile stress, compressive stress, bending stress and multiple alternating stress combined by alternating shearing stress, axial and radial friction is generated between a rotating part and a non-rotating part of the pump, damage to a shaft sleeve, a mechanical seal, a bearing, an impeller, a bearing box and the pump shaft is caused, operation noise and vibration of the pump are increased, various messy vibration frequency spectrums are generated, the vibration cannot be eliminated or adjusted to achieve frequency spectrum balance, vibration is eliminated, and the bolts or connections of the pump and the pump set are loosened and the mechanical seal is seriously damaged, so that leakage of conveying media or serious damage to the pump set is caused, and serious accident potential risks are aggravated; the axial force and the radial force are continuously and alternately overlapped on the pump shaft to increase the damage speed of the pump shaft, and multiple alternate fatigue fracture of the pump shaft can occur when the pump shaft is serious, so that the pump set stops running to cause serious accidents and irrecoverable huge loss, the running stability, the reliability and the safety of the pump are seriously reduced, the running and the service life of the pump are shortened, and the running, overhauling and maintenance cost of the pump set is increased.

Disclosure of utility model

The utility model aims to overcome the defects of the prior art, and provides a pump cavity of a split pump, which can eliminate the axial force generated by an impeller in the operation process and the radial force generated by high-low pressure liquid in the impeller cavity to the impeller in the operation process, so that the axial stress vibration and the radial stress vibration of a rotor assembly are eliminated, the operation stability and the reliability of the pump are ensured, and the operation and the service life of the pump are prolonged.

In order to solve the technical problems, the utility model adopts the following technical scheme:

The pump cavity of the split pump is enclosed by a pump body and a pump cover to form a cavity structure, and a driving side mechanical seal chamber, a first-stage suction chamber, an inducer chamber, a positive impeller chamber, an impeller pressure relief chamber, a counter impeller chamber, a secondary suction chamber and a high-pressure side mechanical seal chamber are sequentially arranged from a driving end to a high-pressure end of the pump cavity; the inlet of the pump cavity, the first-stage suction chamber and the inducer chamber are sequentially communicated; the positive impeller chamber comprises a first-stage positive impeller chamber, a plurality of secondary positive impeller chambers and a final-stage positive impeller chamber which are sequentially communicated; the first-stage positive impeller chamber is communicated with the inducer chamber, a positive impeller pumping chamber, a positive impeller annular chamber and a positive impeller suction chamber which are sequentially communicated are formed between two adjacent positive impeller chambers, the positive impeller annular chamber is arranged on the radial outer side of the positive impeller pumping chamber in a surrounding mode and the radial outer side of the positive impeller suction chamber in a surrounding mode, the positive impeller pumping chamber and the positive impeller suction chamber are separated by a positive impeller mouth ring mounting position, and the positive impeller pumping chamber is arranged on the periphery of the last positive impeller chamber in a surrounding mode and is communicated with the positive impeller chamber; the positive impeller suction chamber is arranged on one axial side of the next positive impeller chamber and is communicated with the positive impeller chamber; the radial outer side of the final-stage positive impeller chamber is provided with a positive impeller water-pressing volute chamber, the upper end of the positive impeller water-pressing volute chamber is communicated with the upper end of the secondary suction chamber through a pump cover transition channel, the lower end of the positive impeller water-pressing volute chamber is communicated with the lower end of the secondary suction chamber through a pump body transition channel, and the pump cover transition channel and the pump body transition channel are symmetrically arranged up and down by taking a pump shaft as a center; the back impeller chamber comprises a first-stage back impeller chamber, a plurality of secondary back impeller chambers and a final-stage back impeller chamber which are sequentially communicated; the first-stage counter-impeller chamber is communicated with the secondary suction chamber, a counter-impeller pumping chamber, a counter-impeller annular chamber and a counter-impeller suction chamber which are sequentially communicated are formed between two adjacent counter-impeller chambers, the counter-impeller annular chamber is arranged on the radial outer side of the counter-impeller pumping chamber in a surrounding mode and the radial outer side of the counter-impeller suction chamber in a surrounding mode, the counter-impeller pumping chamber and the counter-impeller suction chamber are separated by a counter-impeller opening ring installation position, and the counter-impeller pumping chamber is arranged on the periphery of the last counter-impeller chamber in a surrounding mode and is communicated with the counter-impeller chamber; the counter-impeller suction chamber is arranged at one axial side of the next counter-impeller chamber and is communicated with the counter-impeller chamber; the radial outer side of the final stage counter impeller chamber is provided with a counter impeller water-pressing volute chamber which is communicated with an outlet of the pump cavity; the impeller pressure release chamber is communicated with the positive impeller annular chamber corresponding to the last secondary positive impeller chamber through a pressure release pipeline.

As a preferable scheme of the utility model, the number of the positive impeller chamber, the positive impeller pumping chamber, the positive impeller annular chamber and the positive impeller suction chamber is the same as that of the counter impeller chamber, the counter impeller pumping chamber, the counter impeller annular chamber and the counter impeller suction chamber, and the positive impeller pumping chamber, the positive impeller annular chamber and the positive impeller suction chamber are symmetrically arranged left and right by taking the impeller pressure release chamber as the center; the radial cross-sectional shape of the positive impeller chamber, the radial cross-sectional shape of the positive impeller pumping chamber, the radial cross-sectional shape of the positive impeller annular chamber, the radial cross-sectional shape of the positive impeller suction chamber, the radial cross-sectional shape of the counter impeller pumping chamber, the radial cross-sectional shape of the counter impeller annular chamber and the radial cross-sectional shape of the counter impeller suction chamber are all circular.

As a preferable scheme of the utility model, a first-stage suction diversion cone through which the rotor assembly can pass is formed in the first-stage suction chamber; the outer wall surface of the first-stage suction guide cone and the inner wall surface of the first-stage suction chamber are in smooth transition, and the outer diameter of the first-stage suction guide cone is gradually reduced from the first-stage suction chamber to the inducer chamber.

As a preferable scheme of the utility model, an inducer suction chamber is formed at the junction of the first-stage suction chamber and the inducer chamber, and the cone end of the first-stage suction guide cone extends into the inducer suction chamber.

As a preferable mode of the utility model, a secondary suction guide cone through which the rotor assembly can pass is formed in the secondary suction chamber; the outer wall surface of the secondary suction guide cone and the inner wall surface of the secondary suction chamber are in smooth transition, and the outer diameter of the secondary suction guide cone gradually decreases from the secondary suction chamber to the primary counter-impeller chamber.

As a preferable scheme of the utility model, the radial outer periphery of the driving side mechanical seal chamber is provided with a driving side mechanical seal control chamber which is adjacent to and not communicated with the driving side mechanical seal chamber; the radial outer periphery of the high-pressure side mechanical seal chamber is provided with a high-pressure side mechanical seal control chamber which is adjacent to the high-pressure side mechanical seal chamber and is not communicated with the high-pressure side mechanical seal chamber.

As a preferable scheme of the utility model, the driving side machine sealing chamber and the high-pressure side machine sealing chamber are respectively provided with a medium heat exchange inlet and a medium heat exchange outlet which are connected with a medium heat exchange system, and the driving side machine sealing temperature control chamber and the high-pressure side machine sealing temperature control chamber are respectively provided with a medium temperature control inlet and a medium temperature control outlet which are connected with a medium temperature control system.

As a preferable scheme of the utility model, a plurality of circumferentially uniformly distributed pumping chamber guide vanes are formed in the positive impeller pumping chamber and the counter impeller pumping chamber.

As a preferable scheme of the utility model, a plurality of suction chamber guide vanes which are uniformly distributed circumferentially are formed in the positive impeller suction chamber and the counter impeller suction chamber.

As the preferable scheme of the utility model, a plurality of circumferentially uniformly distributed water pressing volute guide vanes are formed in the positive impeller water pressing volute and the counter impeller water pressing volute.

Compared with the prior art, the pump cavity for the split pump has the beneficial effects that:

(1) According to the utility model, through the positive impeller chambers and the counter impeller chambers, the positive impellers and the counter impellers form a back-to-back double-suction symmetrical structure, so that axial forces generated by the impellers in the running process of a rotor assembly of the pump are mutually offset;

(2) According to the utility model, the impeller pressure release chamber is arranged between the final-stage positive impeller chamber and the final-stage negative impeller chamber, and is communicated with the final-stage secondary positive impeller chamber through the pressure release pipeline, when high-pressure liquid in the final-stage negative impeller chamber enters the impeller pressure release chamber through the impeller hub fit clearance, the high-pressure liquid in the final-stage negative impeller chamber flows into the positive impeller annular chamber corresponding to the final-stage secondary positive impeller chamber through the pressure release pipeline to be decompressed and flows into the secondary positive impeller chamber, and is pressurized again through the secondary positive impeller, and at the moment, after the high-pressure liquid in the impeller pressure release chamber passes through the pressure release, the liquid pressure in the impeller pressure release chamber and the liquid pressure in the final-stage positive impeller chamber reach complete balance, so that a rear cover plate of the final-stage positive impeller is free from the action of the liquid pressure and does not generate axial force, and therefore, the axial force is eliminated in the operation process of the rotor assembly, meanwhile, the generation of medium vortex is prevented, the hydraulic efficiency is improved, and cavitation is prevented;

(3) According to the utility model, through the pump cover transition channel and the pump body transition channel which are arranged vertically symmetrically, and the positive impeller pumping chamber, the positive impeller annular chamber, the positive impeller suction chamber, the counter impeller pumping chamber, the counter impeller annular chamber and the counter impeller suction chamber which are circular in radial section are arranged between the impeller stages, radial hydraulic impact of the pump cavity is mutually counteracted, so that radial balance is achieved.

In summary, the pump cavity of the split pump can eliminate the axial force generated by the impeller in the operation process, so that the bearing does not bear the axial force of the pump and the pump shaft does not bear the axial tensile stress and the compressive stress, thereby eliminating the axial stress vibration of the rotor assembly, ensuring the stable and reliable operation of the pump and prolonging the operation and service life of the pump; the radial force generated by the high-low pressure liquid in the impeller cavity to the impeller in the operation process can be eliminated, so that the pump shaft is not subjected to bending stress and alternating shearing stress, radial stress vibration of the rotor assembly is eliminated, stable and reliable operation of the pump is ensured, and the operation and service life of the pump are prolonged.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present utility model, the drawings of the embodiments will be briefly described below.

FIG. 1 is a schematic diagram of a pump cavity of a split pump according to an embodiment of the present utility model;

FIG. 2 is a cross-sectional view taken in the direction A-A of the structure shown in FIG. 1;

fig. 3 is a cross-sectional view in the direction B-B of the structure shown in fig. 1.

The marks in the figure:

A pump body 1; a pump cover 2; a driving side machine sealing chamber 3; a first stage suction chamber 4; an inducer chamber 5; a positive impeller chamber 6; a first stage positive impeller chamber 61; a secondary positive impeller chamber 62; a final stage positive impeller chamber 63; an impeller pressure relief chamber 7 and a counter impeller chamber 8; a primary counter-impeller chamber 81 and a secondary counter-impeller chamber 82; a final stage counter-impeller chamber 83; a secondary suction chamber 9; a high pressure side envelope 10; an inlet 11 of the pump chamber; a positive impeller pumping chamber 12; a positive impeller annular chamber 13; a positive impeller suction chamber 14; a positive impeller collar mounting location 15; a positive impeller water-pressing volute 16; a pump cap transition passage 17; a pump body transition passage 18; a counter-impeller pumping chamber 19; a counter-impeller annular chamber 20; a counter-impeller suction chamber 21; counter impeller collar mount 22; the counter-impeller water-pressing volute 23; an outlet 24 of the pump chamber; a pressure relief conduit 25; a first stage suction cone 26; inducer suction chamber 27; a secondary suction flow cone 28; a drive side machine seal control chamber 29; a high-pressure side mechanical seal control chamber 30; a pumping chamber guide vane 31; suction chamber vanes 32.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

In the description of the present utility model, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present utility model and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, a number means one or more, a number means two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and above, below, within, etc. are understood to include the present number. If described as first, is used solely for the purpose of distinguishing between technical features and does not necessarily require a relative importance or implication or to implicitly indicate the number of technical features indicated or to implicitly indicate the precedence of the technical features indicated.

In the description of the present utility model, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present utility model can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.

Referring to fig. 1 to 3, a pump cavity of a split pump according to an embodiment of the utility model will be described.

As shown in fig. 1 to 3, in a preferred embodiment of the present utility model, a pump cavity of a split pump is enclosed by a pump body 1 and a pump cover 2 to form a cavity structure, and the pump cavity is sequentially provided with a driving side mechanical seal chamber 3, a first stage suction chamber 4, an inducer chamber 5, a positive impeller chamber 6, an impeller pressure release chamber 7, a counter impeller chamber 8, a secondary suction chamber 9 and a high pressure side mechanical seal chamber 10 along a driving end to a high pressure end; the inlet 11 of the pump cavity, the first-stage suction chamber 4 and the inducer chamber 5 are sequentially communicated; the positive impeller chamber 6 comprises a first-stage positive impeller chamber 61, a plurality of secondary positive impeller chambers 62 and a final-stage positive impeller chamber 63 which are sequentially communicated; the first-stage positive impeller chamber 61 is communicated with the inducer chamber 5, a positive impeller pumping chamber 12, a positive impeller annular chamber 13 and a positive impeller suction chamber 14 which are sequentially communicated are formed between two adjacent positive impeller chambers 6, the positive impeller annular chamber 13 is surrounded on the radial outer side of the positive impeller pumping chamber 12 and the radial outer side of the positive impeller suction chamber 14, the positive impeller pumping chamber 12 and the positive impeller suction chamber 14 are separated by a positive impeller ring mounting position 15, and the positive impeller pumping chamber 12 is surrounded on the periphery of the last positive impeller chamber 6 and is communicated with the positive impeller chamber 6; the positive impeller suction chamber 14 is arranged at one axial side of the next positive impeller chamber 6 and is communicated with the positive impeller chamber 6; the radial outer side of the final stage positive impeller chamber 63 is surrounded by a positive impeller water-pressing volute chamber 16, the upper end of the positive impeller water-pressing volute chamber 16 is communicated with the upper end of the secondary suction chamber 9 through a pump cover transition channel 17, the lower end of the positive impeller water-pressing volute chamber 16 is communicated with the lower end of the secondary suction chamber 9 through a pump body transition channel 18, and the pump cover transition channel 17 and the pump body transition channel 18 are symmetrically arranged up and down by taking a pump shaft as a center; the counter-impeller chamber 8 comprises a first-stage counter-impeller chamber 81, a plurality of secondary counter-impeller chambers 82 and a final-stage counter-impeller chamber 83 which are sequentially communicated; the primary counter-impeller chamber 81 is communicated with the secondary suction chamber 9, a counter-impeller pumping chamber 19, a counter-impeller annular chamber 20 and a counter-impeller suction chamber 21 which are sequentially communicated are formed between two adjacent counter-impeller chambers 8, the counter-impeller annular chamber 20 is enclosed on the radial outer side of the counter-impeller pumping chamber 19 and the radial outer side of the counter-impeller suction chamber 21, the counter-impeller pumping chamber 19 and the counter-impeller suction chamber 21 are separated by a counter-impeller ring mounting position 22, and the counter-impeller pumping chamber 19 is enclosed on the periphery of the last counter-impeller chamber 8 and is communicated with the counter-impeller chamber 8; the counter-impeller suction chamber 21 is arranged at one axial side of the next counter-impeller chamber 8 and is communicated with the counter-impeller chamber 8; the radial outer side of the final stage counter-impeller chamber 83 is provided with a counter-impeller water-pressing volute 23, and the counter-impeller water-pressing volute 23 is communicated with an outlet 24 of the pump cavity; the impeller pressure relief chamber 7 communicates with the positive impeller annular chamber 13 corresponding to the last secondary positive impeller chamber 62 via a pressure relief conduit 25.

In this embodiment, the number of the positive impeller chambers 6, the positive impeller pumping chamber 12, the positive impeller annular chamber 13 and the positive impeller suction chamber 14 is the same as the number of the counter impeller chambers, the counter impeller pumping chamber 19, the counter impeller annular chamber 20 and the counter impeller suction chamber 21, and the positive impeller pumping chambers are symmetrically arranged around the impeller pressure release chamber 7; the radial cross-section of the positive impeller chamber 6, the radial cross-section of the positive impeller pumping chamber 12, the radial cross-section of the positive impeller annular chamber 13, the radial cross-section of the positive impeller suction chamber 14, the radial cross-section of the counter impeller chamber 8, the radial cross-section of the counter impeller pumping chamber 19, the radial cross-section of the counter impeller annular chamber 20 and the radial cross-section of the counter impeller suction chamber 21 are all circular, compared with a spiral volute type runner, the structure is simple, the volume space is small, the axial dimension of a pump cavity is favorably shortened, the design of the runner can be completed by using a modularized form of axial superposition extension, the number of impeller stages is favorably increased or reduced, and the die structure is simple and the cost is low. In addition, the pump cover transition channel 17 is formed in the pump cover 2, and the pump body transition channel 18 is formed in the pump body 1, so that the structure is compact and the strength is high.

The pump cavity of the split pump according to the embodiment of the utility model has the technical key points that:

First, the pump cavity of the split pump in the embodiment of the utility model enables the positive impellers and the counter impellers to form a back-to-back double-suction symmetrical structure through the positive impeller chambers 6 and the counter impeller chambers 8, so that axial forces generated by the impellers in the running process of the rotor assembly of the pump are mutually offset.

Secondly, in the pump cavity of the split pump according to the embodiment of the present utility model, the impeller pressure release chamber 7 is disposed between the final stage positive impeller chamber 63 and the final stage negative impeller chamber 83, when the high-pressure liquid in the final stage negative impeller chamber 83 enters the impeller pressure release chamber 7 through the impeller hub fit gap, the high-pressure liquid in the final stage negative impeller chamber 83 flows into the positive impeller annular chamber 13 corresponding to the final secondary positive impeller chamber 62 through the pressure release pipeline 25 to release pressure, flows into the secondary positive impeller chamber 62, and is pressurized again by the secondary positive impeller, at this time, after the high-pressure liquid in the impeller pressure release chamber 7 is released, the liquid pressure in the impeller pressure release chamber 7 and the liquid pressure in the final stage positive impeller chamber 63 are completely balanced, so that the back cover plate of the final stage positive impeller is not affected by the liquid pressure and does not generate axial force, thereby eliminating the axial force in the operation process of the rotor assembly, simultaneously preventing the generation of medium vortex, improving the hydraulic efficiency, and preventing cavitation.

Third, through the pump cover transition channel 17 and the pump body transition channel 18 which are arranged symmetrically up and down, and a round positive impeller pumping chamber 12, a positive impeller annular chamber 13, a positive impeller suction chamber 14, a counter impeller pumping chamber 19, a counter impeller annular chamber 20 and a counter impeller suction chamber 21 are arranged between impeller stages, radial hydraulic impact of the pump cavity is mutually offset, so that radial balance is achieved.

In summary, the pump cavity of the split pump can eliminate the axial force generated by the impeller in the operation process, so that the bearing does not bear the axial force of the pump and the pump shaft does not bear the axial tensile stress and the compressive stress, thereby eliminating the axial stress vibration of the rotor assembly, ensuring the stable and reliable operation of the pump and prolonging the operation and service life of the pump; the radial force generated by the high-low pressure liquid in the impeller cavity to the impeller in the operation process can be eliminated, so that the pump shaft is not subjected to bending stress and alternating shearing stress, radial stress vibration of the rotor assembly is eliminated, stable and reliable operation of the pump is ensured, and the operation and service life of the pump are prolonged.

Illustratively, the first stage suction plenum 4 has a first stage suction cone 26 formed therein through which the rotor assembly passes; the outer wall surface of the first-stage suction guide cone 26 and the inner wall surface of the first-stage suction chamber 4 are in smooth transition, and the outer diameter of the first-stage suction guide cone 26 gradually decreases from the first-stage suction chamber 4 to the inducer chamber 5. Further, an inducer suction chamber 27 is formed at the junction of the primary suction chamber 4 and the inducer chamber 5, and the tapered end of the primary suction guide cone 26 extends into the inducer suction chamber 27. By the design, the pressurized medium in the first-stage suction chamber 4 can not radially impact the pump shaft and the inducer, the medium in the first-stage suction chamber 4 is radially and smoothly converted into axial diversion and flows into the inducer suction chamber 27, medium vortex is prevented from being generated, hydraulic efficiency is improved, and cavitation and radial force generation and vibration of a rotor assembly are prevented.

It should be noted that, a spiral flow blocking channel is formed between the first-stage suction flow guiding cone 26 and the rotor assembly (e.g. pump shaft). The flow blocking channel plays a role in blocking flow, can effectively prevent pressurized liquid in the first-stage suction chamber 4 from entering the driving-side mechanical seal chamber 3 to impact the mechanical seal in the driving-side mechanical seal chamber, and effectively isolate impurities in media in the first-stage suction chamber 4 from entering the driving-side mechanical seal chamber 3 to prevent damage to the mechanical seal, so that the sealing performance of the driving side of the pump main body is ensured, and the pump conveying media are effectively prevented from leaking along the pump shaft.

Illustratively, a secondary suction cone 28 is formed in the secondary suction chamber 9 for the rotor assembly to pass through; the outer wall surface of the secondary suction guide cone 28 smoothly transitions with the inner wall surface of the secondary suction chamber 9, and the outer diameter of the secondary suction guide cone 28 gradually decreases from the secondary suction chamber 9 to the primary counter-impeller chamber 81. By the design, the pressurized medium in the secondary suction chamber 9 can not radially impact the pump shaft, the medium in the secondary suction chamber 9 is radially and smoothly converted into axial flow to be guided into the suction inlet of the primary counter-impeller chamber 81, the generation of medium vortex is prevented, the hydraulic efficiency is improved, and cavitation generation, the generation of radial force of the rotor assembly and vibration are prevented.

Illustratively, a driving side machine seal control chamber 29 which is adjacent to and not communicated with the driving side machine seal chamber 3 is arranged on the radial outer periphery of the driving side machine seal chamber; the driving side mechanical seal temperature control chamber 29 is provided with a medium temperature control inlet and a medium temperature control outlet which are connected with a medium temperature control system. In some embodiments, the medium temperature control system can inject cold medium and hot medium into the driving side mechanical seal temperature control chamber 29, when the medium temperature in the driving side mechanical seal chamber 3 is too high, the cold medium can be injected into the driving side mechanical seal temperature control chamber 29 through the medium temperature control inlet to exchange heat with the medium in the driving side mechanical seal chamber 3, so that the medium temperature in the driving side mechanical seal chamber 3 is reduced; when the medium temperature in the driving side machine sealing chamber 3 is too low, especially before initial starting, a heat medium can be injected into the driving side machine sealing temperature control chamber 29 through the medium temperature control inlet to exchange heat with the medium in the driving side machine sealing chamber 3, so that the medium temperature in the driving side machine sealing chamber 3 is increased; after heat exchange, the medium in the driving side mechanical seal temperature control chamber 29 flows back to the medium temperature control system through the medium temperature control outlet, so that medium circulation is formed. Thus, the drive side seal control chamber 29 can cool down and warm up the drive side seal chamber 3.

Illustratively, the driving side mechanical seal chamber 3 is provided with a medium heat exchange inlet and a medium heat exchange outlet which are connected with a medium heat exchange system (comprising a heat exchanger and related pipelines). In some embodiments, a mechanical seal sleeved on a pump shaft is arranged in the driving side mechanical seal chamber 3, and the mechanical seal is driven to rotate by the pump shaft, so that a medium in the driving side mechanical seal chamber 3 is pressurized and conveyed into a heat exchanger for heat exchange through a medium heat exchange outlet and a pipeline, the medium after heat exchange flows back to the driving side mechanical seal chamber 3 from a medium heat exchange inlet, and the mechanical seal in the driving side mechanical seal chamber is independently washed, cooled and preheated.

Illustratively, a high-pressure side mechanical seal control chamber 30 which is adjacent to and not communicated with the radial outer periphery of the high-pressure side mechanical seal chamber 10 is arranged; the high-pressure side mechanical seal temperature control chamber 30 is provided with a medium temperature control inlet and a medium temperature control outlet which are connected with a medium temperature control system. In some embodiments, the medium temperature control system can inject cold and hot medium into the high-pressure side mechanical seal control chamber 30, when the medium temperature in the high-pressure side mechanical seal chamber 10 is too high, cold medium can be injected into the high-pressure side mechanical seal control chamber 30 through the medium temperature control inlet to exchange heat with the medium in the high-pressure side mechanical seal chamber 10, so that the medium temperature in the high-pressure side mechanical seal chamber 10 is reduced; when the medium temperature in the high-pressure side mechanical seal chamber 10 is too low, especially before initial start-up, a heat medium can be injected into the high-pressure side mechanical seal temperature control chamber 30 through the medium temperature control inlet to exchange heat with the medium in the high-pressure side mechanical seal chamber 10, so that the medium temperature in the high-pressure side mechanical seal chamber 10 is increased; after heat exchange, the medium in the high-pressure side mechanical seal temperature control chamber 30 flows back to the medium temperature control system through the medium temperature control outlet, so that medium circulation is formed. Thus, the high-pressure side seal control chamber 30 can cool down and preheat the high-pressure side seal chamber 10.

Illustratively, the high-pressure side mechanical seal chamber 10 is provided with a medium heat exchange inlet and a medium heat exchange outlet connected with a medium heat exchange system (comprising a heat exchanger, a filter and a pipeline). In some embodiments, a mechanical seal fixedly sleeved on the pump shaft is disposed in the high-pressure side mechanical seal chamber 10, and the mechanical seal is driven to rotate by the pump shaft, so that a medium in the high-pressure side mechanical seal chamber 10 is pressurized and conveyed into the heat exchanger for heat exchange through a medium heat exchange outlet and a pipeline, and the medium after heat exchange flows back to the high-pressure side mechanical seal chamber 10 from a medium heat exchange inlet, and independently washes, cools and warms up the mechanical seal in the high-pressure side mechanical seal chamber.

Illustratively, a plurality of pumping chamber guide vanes 31 which are uniformly distributed circumferentially are formed in the positive impeller pumping chamber 12 and the counter impeller pumping chamber 19; a plurality of suction chamber guide vanes 32 which are uniformly distributed circumferentially are formed in the positive impeller suction chamber 14 and the negative impeller suction chamber 21; a plurality of circumferentially and uniformly distributed water-pressing volute guide vanes are formed in the positive impeller water-pressing volute 16 and the counter impeller water-pressing volute 23. Therefore, the suction chamber guide vane 32, the pumping chamber guide vane 31 and the pumping volute guide vane can further uniformly distribute the respective corresponding suction chamber, pumping chamber and pumping volute, so that the pressure balance degree of the circumference of the impeller is improved, the blades and the outer circle of each impeller can not generate radial force and are transmitted to the rotor assembly, and the radial force of the pump in the running process is further eliminated.

The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present utility model, and these modifications and substitutions should also be considered as being within the scope of the present utility model.

Claims (10)

1. The pump cavity of the split pump is enclosed by a pump body and a pump cover to form a cavity structure, and is characterized in that a driving side mechanical seal chamber, a first-stage suction chamber, an inducer chamber, a positive impeller chamber, an impeller pressure release chamber, a counter impeller chamber, a secondary suction chamber and a high-pressure side mechanical seal chamber are sequentially arranged from a driving end to a high-pressure end of the pump cavity; the inlet of the pump cavity, the first-stage suction chamber and the inducer chamber are sequentially communicated; the positive impeller chamber comprises a first-stage positive impeller chamber, a plurality of secondary positive impeller chambers and a final-stage positive impeller chamber which are sequentially communicated; the first-stage positive impeller chamber is communicated with the inducer chamber, a positive impeller pumping chamber, a positive impeller annular chamber and a positive impeller suction chamber which are sequentially communicated are formed between two adjacent positive impeller chambers, the positive impeller annular chamber is arranged on the radial outer side of the positive impeller pumping chamber in a surrounding mode and the radial outer side of the positive impeller suction chamber in a surrounding mode, the positive impeller pumping chamber and the positive impeller suction chamber are separated by a positive impeller mouth ring mounting position, and the positive impeller pumping chamber is arranged on the periphery of the last positive impeller chamber in a surrounding mode and is communicated with the positive impeller chamber; the positive impeller suction chamber is arranged on one axial side of the next positive impeller chamber and is communicated with the positive impeller chamber; the radial outer side of the final-stage positive impeller chamber is provided with a positive impeller water-pressing volute chamber, the upper end of the positive impeller water-pressing volute chamber is communicated with the upper end of the secondary suction chamber through a pump cover transition channel, the lower end of the positive impeller water-pressing volute chamber is communicated with the lower end of the secondary suction chamber through a pump body transition channel, and the pump cover transition channel and the pump body transition channel are symmetrically arranged up and down by taking a pump shaft as a center; the back impeller chamber comprises a first-stage back impeller chamber, a plurality of secondary back impeller chambers and a final-stage back impeller chamber which are sequentially communicated; the first-stage counter-impeller chamber is communicated with the secondary suction chamber, a counter-impeller pumping chamber, a counter-impeller annular chamber and a counter-impeller suction chamber which are sequentially communicated are formed between two adjacent counter-impeller chambers, the counter-impeller annular chamber is arranged on the radial outer side of the counter-impeller pumping chamber in a surrounding mode and the radial outer side of the counter-impeller suction chamber in a surrounding mode, the counter-impeller pumping chamber and the counter-impeller suction chamber are separated by a counter-impeller opening ring installation position, and the counter-impeller pumping chamber is arranged on the periphery of the last counter-impeller chamber in a surrounding mode and is communicated with the counter-impeller chamber; the counter-impeller suction chamber is arranged at one axial side of the next counter-impeller chamber and is communicated with the counter-impeller chamber; the radial outer side of the final stage counter impeller chamber is provided with a counter impeller water-pressing volute chamber which is communicated with an outlet of the pump cavity; the impeller pressure release chamber is communicated with the positive impeller annular chamber corresponding to the last secondary positive impeller chamber through a pressure release pipeline.

2. The pump cavity of the split pump according to claim 1, wherein the number of the positive impeller chamber, the positive impeller pumping chamber, the positive impeller annular chamber and the positive impeller suction chamber is the same as the number of the counter impeller chamber, the counter impeller pumping chamber, the counter impeller annular chamber and the counter impeller suction chamber and is symmetrically arranged left and right centering on the impeller pressure release chamber; the radial cross-sectional shape of the positive impeller chamber, the radial cross-sectional shape of the positive impeller pumping chamber, the radial cross-sectional shape of the positive impeller annular chamber, the radial cross-sectional shape of the positive impeller suction chamber, the radial cross-sectional shape of the counter impeller pumping chamber, the radial cross-sectional shape of the counter impeller annular chamber and the radial cross-sectional shape of the counter impeller suction chamber are all circular.

3. The pump chamber of claim 1, wherein the primary suction chamber defines a primary suction flow cone through which the rotor assembly passes; the outer wall surface of the first-stage suction guide cone and the inner wall surface of the first-stage suction chamber are in smooth transition, and the outer diameter of the first-stage suction guide cone is gradually reduced from the first-stage suction chamber to the inducer chamber.

4. A pump cavity of a split pump according to claim 3, wherein an inducer suction chamber is formed at the junction of the primary suction chamber and the inducer chamber, and the tapered end of the primary suction guide cone extends into the inducer suction chamber.

5. The pump chamber of the split pump of claim 1, wherein a secondary suction flow cone is formed in the secondary suction chamber for the rotor assembly to pass through; the outer wall surface of the secondary suction guide cone and the inner wall surface of the secondary suction chamber are in smooth transition, and the outer diameter of the secondary suction guide cone gradually decreases from the secondary suction chamber to the primary counter-impeller chamber.

6. The pump cavity of the split pump according to claim 1, wherein a drive side mechanical seal control room which is adjacent to and not communicated with the drive side mechanical seal room is arranged on the radial outer periphery of the drive side mechanical seal room; the radial outer periphery of the high-pressure side mechanical seal chamber is provided with a high-pressure side mechanical seal control chamber which is adjacent to the high-pressure side mechanical seal chamber and is not communicated with the high-pressure side mechanical seal chamber.

7. The pump cavity of the split pump according to claim 6, wherein the driving side machine sealing chamber and the high pressure side machine sealing chamber are respectively provided with a medium heat exchange inlet and a medium heat exchange outlet which are connected with a medium heat exchange system, and the driving side machine sealing temperature control chamber and the high pressure side machine sealing temperature control chamber are respectively provided with a medium temperature control inlet and a medium temperature control outlet which are connected with the medium temperature control system.

8. The pump cavity of the split pump according to claim 1, wherein a plurality of pumping chamber guide vanes which are uniformly distributed circumferentially are formed in the positive impeller pumping chamber and the counter impeller pumping chamber.

9. The pump cavity of the split pump according to claim 1, wherein a plurality of suction chamber guide vanes which are uniformly distributed circumferentially are formed in each of the positive impeller suction chamber and the negative impeller suction chamber.

10. The pump cavity of the split pump according to claim 1, wherein a plurality of circumferentially uniformly distributed pumping chamber guide vanes are formed in each of the positive impeller pumping chamber and the counter impeller pumping chamber.