CN110206734B

CN110206734B - Centrifugal pump shaft and conveying equipment

Info

Publication number: CN110206734B
Application number: CN201810167283.7A
Authority: CN
Inventors: 庞义华; 钟秋宏; 马英群; 张国明; 赵兴国; 何奋彪; 樊亚军; 何生民; 张怀洲; 王荣; 张国辉; 哈兴凯
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2018-02-28
Filing date: 2018-02-28
Publication date: 2021-04-30
Anticipated expiration: 2038-02-28
Also published as: CN110206734A

Abstract

The invention provides a centrifugal pump and a conveying device, comprising: the balance mechanism comprises a main shaft, an impeller, a balance sleeve and a balance column; the balance sleeve is arranged at the rear end of the pump, the balance column is arranged in the balance sleeve in a penetrating mode, and a preset gap is formed between the inner wall of the balance sleeve and the outer wall of the balance column; the balance column is provided with a shaft hole which is sleeved outside the rear end of the main shaft away from the front end of the pump; the balance column is connected with the main shaft through a stopping device, the stopping device is used for preventing the balance column from moving along the direction parallel to the axis of the main shaft, and the stopping device is also used for preventing the balance column from rotating relative to the main shaft; the balance column is provided with a back-flushing hole, the first end of the back-flushing hole is communicated with the gap, and the second end of the back-flushing hole is communicated with an outlet of the pump. When the main shaft rotates, the balance column can be driven to rotate together, the liquid medium in the back flushing hole can be sprayed out from the first end of the back flushing hole under the action of centrifugal force, and then particles between the balance column and the balance sleeve are flushed away, so that the particles are prevented from blocking the preset gap.

Description

Centrifugal pump shaft and conveying equipment

Technical Field

The invention relates to the technical field of centrifugal pump manufacturing, in particular to a centrifugal pump and conveying equipment.

Background

In petrochemical engineering devices, a multistage centrifugal pump is commonly used for improving the conveying pressure and conveying distance of process media, and generally comprises a main shaft, an impeller and a pump body, wherein the impeller is arranged on the main shaft and is in transmission connection with the main shaft; when the main shaft rotates, the impeller is driven to rotate, the liquid medium on the impeller flows to the edge of the impeller under the action of centrifugal force and then enters the flow channel of the pump body, the pressure of the liquid medium in the flow channel is increased and flows to the outlet of the pump, and the pressure of the outlet of the pump is higher than the pressure of the inlet of the pump. Under the action of the pressure, the impeller receives an axial force towards the front end of the pump, and the axial force increases the pressure between the main shaft and the pump body, so that how to reduce the pressure between the main shaft and the pump body becomes a hot point of research.

In the prior art, a balance sleeve is often arranged at the rear end of the pump and connected with the pump body, a balance column is arranged in the balance sleeve in a penetrating manner, a preset gap is formed between the balance sleeve and the balance column, a shaft hole is formed in the balance column, and the rear end of a main shaft penetrates into the shaft hole and is fixed with the balance column. When the pump during operation, the liquid medium of export can enter into the rear end that the balancing column deviates from the pump mouth through predetermineeing the clearance to the pressure of liquid medium can reduce at flow in-process, make the pressure of balancing column front end be higher than the pressure of balancing column rear end, and then liquid medium can give the balancing column hydraulic pressure force that deviates from the pump front end, and hydraulic pressure force can offset most axial force, and then reduces the effort between the main shaft and the pump body, realizes the balance to axial force.

However, in the prior art, because the liquid medium contains polymer, crystal, coke, oxide, sulfide and other difficult-to-dissolve particles, when the centrifugal pump works, the particles enter the preset gap between the balance sleeve and the balance column, and easily block the preset gap, thereby preventing the liquid medium from flowing in the preset gap, and causing axial force balance failure.

Disclosure of Invention

In view of this, the present invention provides a centrifugal pump and a conveying apparatus, so as to solve the problem that a preset gap is easily blocked due to the entry of polymer, crystals, coked substances, oxides, sulfides and other particulate matters in a liquid medium into the preset gap between a balance sleeve and a balance column, and further prevent the liquid medium from flowing in the preset gap, which results in axial force balance failure.

The present invention provides a centrifugal pump comprising: the balance mechanism comprises a main shaft, an impeller, a balance sleeve and a balance column; the main shaft extends from the front end to the rear end of the pump, and the impeller is arranged on the main shaft; the balance sleeve is arranged at the rear end of the pump, the balance column penetrates through the balance sleeve, and a preset gap is formed between the inner wall of the balance sleeve and the outer wall of the balance column; the balance column is provided with a shaft hole, and the rear end of the main shaft extends into the shaft hole; the balance column is connected with the main shaft through a stopping device, the stopping device is used for preventing the balance column from moving along the direction parallel to the axis of the main shaft, and the stopping device is also used for preventing the balance column from rotating relative to the main shaft; and a back flushing hole is formed in the balance column, the first end of the back flushing hole is communicated with the gap, and the second end of the back flushing hole is communicated with an outlet of the pump.

In the centrifugal pump as described above, preferably, the cross-sectional area of the first end of the back-flushing hole is larger than the cross-sectional area of the second end of the back-flushing hole.

In the centrifugal pump as described above, preferably, the shaft hole includes a first section near a front end of the pump and a second section far from the front end of the pump, and a diameter of the first section is larger than a diameter of the second section, the stopper means is provided at the second section, and a second end of the back-flushing hole is located on an inner surface of the first section.

In the centrifugal pump as described above, preferably, the axis of the back-flushing hole forms a predetermined included angle with the end surface of the balancing column.

In the centrifugal pump described above, preferably, a sealing groove is formed in the side wall of the second section, and a sealing ring is installed in the sealing groove.

In the centrifugal pump described above, preferably, the sealing groove is provided in plurality, and the plurality of sealing grooves are provided at intervals along an axis of the balance column.

In the centrifugal pump as described above, preferably, the balance sleeve is provided with a turbulence groove.

In the centrifugal pump as described above, preferably, the turbulence groove is provided at an end of the balance sleeve near a front end of the pump.

In the centrifugal pump as described above, preferably, the plurality of the turbulence grooves are provided at intervals in the circumferential direction of the balance sleeve.

The invention also provides a conveying device, preferably comprising a conveying pipeline and a centrifugal pump as described above, wherein an inlet of the centrifugal pump is used for communicating with the inlet tank, and an outlet of the centrifugal pump is communicated with the conveying pipeline.

According to the centrifugal pump and the conveying equipment provided by the invention, the balance sleeve is arranged at the rear end of the pump, the balance column is arranged in the balance sleeve in a penetrating manner, and a preset gap is formed between the inner wall of the balance sleeve and the outer wall of the balance column; the shaft hole is sleeved outside the rear end of the main shaft, the balance column is connected with the main shaft through the stopping device, the stopping device can prevent the balance column from moving along the direction parallel to the axis of the main shaft, and the stopping device can also prevent the balance column from rotating relative to the main shaft; a back-flushing hole is formed in the side wall, facing the front end of the pump, of the balance column, the first end of the back-flushing hole is communicated with the gap, and the second end of the back-flushing hole is used for being communicated with an outlet of the pump; when the main shaft rotates, the balance column can be driven to rotate together, and the liquid medium in the backwashing holes can be under the action of centrifugal force while the balance column rotates; the particles are sprayed out from the first end of the back flushing hole, and then the particles between the balance column and the balance sleeve are flushed away, so that the particles are prevented from blocking the preset gap.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic view of an installation between a balance sleeve and a balance column in a centrifugal pump provided by an embodiment of the invention;

FIG. 2 is a schematic structural diagram of a balancing column in the centrifugal pump provided by the embodiment of the invention;

FIG. 3 is a schematic structural view of the balance sleeve of FIG. 1;

FIG. 4 is a right side view of the balance sleeve of FIG. 3;

FIG. 5 is a schematic view of the location of the center of mass of the balancing post and the geometric center of the balancing post of FIG. 1;

FIG. 6 is a schematic diagram illustrating the forces applied to the balancing column during rotation in a centrifugal pump according to an embodiment of the present invention;

fig. 7 is a schematic diagram of the position between the balancing pole and the balancing sleeve in fig. 1 when the balancing pole rotates.

Description of reference numerals:

10. a balance sleeve;

20. a balancing column;

30. back flushing the hole;

101. a pressure balance tank;

102. a turbulence groove;

201. a first stage;

202. a second stage;

203. a first stopper key groove;

204. a sealing groove;

o, the geometric center of the equilibrium column;

w, the center of mass of the balancing column;

f. mass eccentricity force;

beta, a preset included angle;

F. hydraulic eccentric force.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the present invention, unless otherwise specifically stated, the terms "mounted," "connected," "fixed," and the like are to be understood broadly, and for example, may be a fixed connection, a detachable connection, and a mechanical connection; they may be directly connected or indirectly connected through an intermediate medium, or they may be connected internally or in any other manner known to those skilled in the art, unless otherwise specifically limited. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

During transport of the liquid medium, it is often necessary to transport the liquid medium from the inlet tank into a processing plant for processing the liquid medium. At this time, a conveying pipeline needs to be arranged between the inlet tank and the processing factory, and because the distance between the inlet tank and the processing equipment is often large, the liquid medium needs to have a large pressure so as to ensure that the liquid medium flows in the conveying pipeline quickly. In the prior art, a centrifugal pump is usually arranged on a conveying pipeline, and the pressure of a liquid medium in the conveying pipeline is improved through the centrifugal pump.

Wherein, the centrifugal pump includes: the pump comprises a pump body, a main shaft and an impeller, wherein the main shaft and the impeller are coaxially arranged, and the main shaft and the impeller are fixedly connected through bolts or other devices, so that the impeller can rotate together with the main shaft, and meanwhile, the impeller cannot move along the axial direction of the main shaft; the pump body is internally provided with a cavity formed by extending the front end to the rear end, the main shaft and the impeller are arranged in the cavity in a penetrating way, the cavity is communicated with an inlet and an outlet on the pump body, the inlet and the outlet are respectively positioned on the side walls of the front end and the rear end of the pump body, and the cavity is provided with a flow channel communicated with the outlet; when the main shaft drives the impeller to rotate, the liquid medium enters from the inlet and contacts with the impeller, and then enters the flow channel under the action of centrifugal force, flows to the outlet and flows out from the outlet. Wherein the front end of main shaft is worn out by the front end of the pump body, and the front end of main shaft passes through the shaft coupling and is connected with drive arrangement, and drive arrangement generally is the device that can output and have certain moment of torsion and rotational speed, for example: an electric motor or an internal combustion engine, etc.

When the main shaft drives the impeller to rotate, the pressure of the liquid medium on one side of the impeller facing the outlet is higher than the pressure of the liquid medium on one side of the impeller facing the inlet, so that the pressure of the outlet of the pump is higher than the pressure of the inlet, the liquid medium in the cavity can provide the impeller with the pressure facing the inlet, the main shaft has the axial force which is parallel to the axis and faces the front end of the main shaft, and the pressure between the main shaft and the pump body is increased.

In order to reduce the pressure between the main shaft and the pump body, a balance sleeve is arranged at the rear end of the pump body and is connected with the pump body; a balance column penetrates through the balance sleeve, a shaft hole is formed in the middle of the balance column, and the rear end of the main shaft is inserted into the shaft hole; a preset gap is formed between the balance sleeve and the balance column, so that the liquid medium positioned at the outlet can enter the rear end of the balance column departing from the outlet through the gap, and the pressure is gradually reduced under the resistance action of the preset gap in the flowing process of the liquid medium; the pressure of the front end and the rear end of the balance column is unequal, namely the pressure of the front end is higher than that of the rear end, and under the action of pressure difference, the balance column is subjected to hydraulic pressure towards the rear end of the main shaft, and the hydraulic pressure is opposite to the axial force in direction, so that most of the axial force can be balanced by the hydraulic pressure, and the acting force between the main shaft and the pump body is further reduced.

However, because polymer, crystal, coke, oxide, sulfide and other insoluble particles exist in the liquid medium, when the centrifugal pump works, the particles enter the gap between the balance sleeve and the balance column along with the liquid medium to further block the gap, the particles entering the gap gradually increase along with the lengthening of the working time, the pressure difference at two ends of the balance column gradually increases, the generated hydraulic pressure gradually increases to cause the transitional balance of the axial force, and when the hydraulic pressure is greater than the axial force, the main shaft presses the thrust bearing arranged at the rear part of the main shaft backwards to increase the temperature of the thrust bearing until the thrust bearing is burnt. Rendering the axial force balance ineffective.

When the preset gap is gradually blocked and becomes small, the device needs to be stopped regularly, and the balance column and the balance sleeve are replaced or cleaned; on one hand, the long-period stable operation and the economic benefit of the production device are influenced, and on the other hand, the large-scale high-power key equipment is frequently stopped and switched, so that the problems of irreversible damage and operation safety are easily caused.

FIG. 1 is a schematic view of an installation between a balance sleeve and a balance column in a centrifugal pump provided by an embodiment of the invention; FIG. 2 is a schematic structural diagram of a balancing column in the centrifugal pump provided by the embodiment of the invention; FIG. 3 is a schematic structural view of the balance sleeve of FIG. 1; FIG. 4 is a right side view of the balance sleeve of FIG. 3; FIG. 5 is a schematic view of the location of the center of mass of the balancing post and the geometric center of the balancing post of FIG. 1; FIG. 6 is a schematic diagram illustrating the forces applied to the balancing column during rotation in a centrifugal pump according to an embodiment of the present invention; fig. 7 is a schematic view of the position between the balance post and the balance sleeve in fig. 1 when the balance post rotates, please refer to fig. 1-7. The present embodiment provides a centrifugal pump, including: a main shaft, an impeller, a balance sleeve 10 and a balance post 20; the main shaft extends from the front end to the rear end of the pump, and the impeller is arranged on the main shaft; the balance sleeve 10 is arranged at the rear end of the pump, the balance column 20 penetrates through the balance sleeve 10, and a preset gap is formed between the inner wall of the balance sleeve 10 and the outer wall of the balance column 20; the balance post 20 is provided with a shaft hole, and the rear end of the main shaft extends into the shaft hole; the balance post 20 is connected with the main shaft through a stopping device, the stopping device is used for preventing the balance post 20 from moving along the direction parallel to the axis of the main shaft, and the stopping device is also used for preventing the balance post 20 from rotating relative to the main shaft; the balance column 20 is provided with a back flushing hole 30, a first end of the back flushing hole 30 is communicated with the gap, and a second end of the back flushing hole 30 is communicated with an outlet of the pump.

The centrifugal pump comprises a pump body, wherein the pump body is cylindrical or prismatic, a cavity with a circular section is formed in the pump body, an inlet and an outlet of the pump are respectively arranged on the side walls of the front end and the rear end of the pump body, and the inlet and the outlet of the pump are communicated with the cavity; in addition, a flow channel is arranged on the side wall of the cavity and communicated with the outlet, so that when the liquid medium on the rotor flies away from the impeller under the centrifugal effect, the liquid medium can enter the flow channel and then flow to the outlet, and the liquid medium is conveyed.

The front end of the main shaft penetrates out of the front end of the pump body and is connected with the main shaft of the motor through a coupling, and the front end of the main shaft can be connected with the pump body through a cylindrical roller bearing; preferably, a bearing hole is formed in the front end of the pump body, a cylindrical roller bearing is sleeved at the front end of the main shaft, and the outer side of the cylindrical roller bearing is connected with the side wall of the bearing hole; in order to prevent the liquid medium in the pump body from overflowing from the bearing hole, an oil seal needs to be arranged at one end, facing the rear end of the main shaft, of the bearing hole in a penetrating mode, so that the bearing hole is sealed. In addition, the rear end of the main shaft is connected with the pump body through two tapered roller thrust bearings which are arranged back to back, so that the axial force and the radial force can be borne to a certain degree, and the axial positioning effect on the main shaft of the pump is achieved.

Specifically, the shape of the impeller is not limited in this embodiment, and it is only necessary to ensure that when the impeller rotates, the liquid medium on the impeller can enter the flow channel in the cavity under the action of the centrifugal force, and then enter the outlet of the pump through the flow channel. Preferably, the impeller may be provided in plurality, and the plurality of impellers are arranged at intervals in the axial direction of the main shaft to increase the outlet pressure of the pump. In addition, the embodiment does not limit the connection mode between the impeller and the main shaft, as long as it is ensured that the main shaft can drive the impeller to rotate when the main shaft rotates, and the impeller cannot move along the axial direction of the main shaft due to the axial force; for example: the impeller can be connected with the main shaft in a key connection mode, and in addition, positioning sleeves can be arranged at two ends of the impeller so as to prevent the impeller from moving along the axial direction; a first shaft shoulder is arranged on the main shaft, the front end of the first positioning sleeve abuts against the first shaft shoulder, the rear end of the first positioning sleeve abuts against the front end of the impeller, the rear end of the impeller abuts against the front end of the second positioning sleeve, and the rear end of the second positioning sleeve abuts against the front end of the balance column 20, so that the impeller is axially positioned; through set up first keyway on the main shaft and set up on the impeller with first keyway complex second keyway, the parallel key wears to establish respectively in first keyway and second keyway, realizes that the transmission of impeller and main shaft is connected.

Specifically, the rear end of the pump body is closed by the balance sleeve 10, the balance post 20 and the seal penetrating the main shaft. In this embodiment, the connection mode between the balance sleeve 10 and the pump body is not limited, as long as the balance sleeve 10 can be prevented from rotating, and the liquid medium in the cavity can be prevented from overflowing from between the balance sleeve 10 and the pump body; for example: the outer wall of the balance sleeve 10 is provided with external threads, the inner wall of the rear end of the cavity is provided with internal threads, and the internal threads and the external threads are matched to realize the connection between the balance sleeve 10 and the pump body; or, a connecting flange is formed on the outer side of the front end of the balance sleeve 10, a mounting hole is formed on the connecting flange, a mounting threaded hole is correspondingly formed on the rear end face of the pump body, and a mounting bolt penetrates through the mounting hole and then is screwed into the mounting threaded hole, so that the balance sleeve 10 is connected with the pump body; in order to enhance the sealing performance between the pump body and the balance sleeve 10, a sealing gasket may be disposed between the balance sleeve 10 and the rear end face of the pump body, and the sealing gasket may be a rubber gasket. Of course, a connecting flange may be formed on the rear end side wall of the balance sleeve 10, the balance sleeve 10 before the connecting flange is inserted into the cavity, and at this time, in order to enhance the sealing performance between the pump body and the balance sleeve 10, a sealing ring may be provided on the side wall of the balance sleeve 10, and the sealing ring may be a rubber ring.

Specifically, in this embodiment, the preset gap between the balance sleeve 10 and the balance column 20 is not limited, as long as it is ensured that in the process of flowing the liquid medium from the front end to the rear end of the gap, the pressure of the liquid medium is gradually reduced under the action of resistance, so that the pressure of the liquid medium at the front end of the balance column 20 is greater than the pressure of the liquid medium at the rear end, and further the balance column 20 is subjected to a hydraulic pressure toward the rear end of the main shaft, so as to counteract the axial force of the liquid medium in most of the cavities to the impeller toward the front end of the main shaft; the size of the preset gap can be reasonably set by a person skilled in the art according to the liquid to be conveyed or the structure of the pump; for example: the preset gap may be 0.14 mm or 0.28 mm, etc.

Preferably, a pressure balance groove 101 is formed in the inner wall of the balance sleeve 10, the pressure balance groove 101 may be an annular groove, and a liquid medium may be stored in the pressure balance groove 101 so as to balance the pressure of the liquid medium in the preset gap.

Preferably, the balance sleeve 10 and the balance post 20 are made of different materials, so as to further avoid the adhesion between the balance sleeve 10 and the balance post 20 when the balance sleeve 10 is overheated, in this embodiment, the balance sleeve 10 is preferably made of 2Cr13, the balance post 20 is preferably made of 3Cr13, and both the balance sleeve 10 and the balance post 20 are subjected to thermal refining after forging, so that the balance sleeve 10 and the balance post 20 have better comprehensive mechanical properties.

Specifically, the stopping device is not limited in this embodiment, as long as it is ensured that the main shaft can drive the balance post 20 to rotate while rotating, and the balance post 20 is prevented from moving along the axial direction of the main shaft; for example: the stopping device can comprise a stopping stud, a stopping hole with an axis perpendicular to the axis of the balance column 20 is formed in the balance column 20, a stopping threaded hole is formed in the main shaft, and the stopping stud penetrates through the stopping hole and is screwed into the stopping threaded hole to realize connection between the balance column 20 and the main shaft. In addition, the stopping device can comprise a stopping sheet and a stopping key, a first stopping key groove 203 extends from the front end to the rear end on the side wall of the shaft hole, the first stopping key groove 203 does not penetrate through the shaft hole, a second stopping key groove is formed in the spindle, and the stopping key is arranged in the first stopping key groove 203 and the second stopping key groove so as to realize transmission connection between the balance column 20 and the spindle and prevent the balance column 20 from moving to the front end of the spindle; the stop piece is arranged at the rear end of the balance column 20, is annular, is provided with a stop groove on the main shaft, and is clamped in the stop groove so as to prevent the balance column 20 from moving towards the rear end of the main shaft.

Specifically, the sectional shape of the backwash holes 30 is not limited in this embodiment, and examples thereof include: the cross section of the back-flushing hole 30 may be in a regular shape such as a circle, an ellipse, a triangle, a rectangle, or other irregular shapes. In addition, the position of the second end of the back flushing hole 30 is not limited in this embodiment as long as the second end of the back flushing hole 30 is communicated with the outlet of the pump, for example: the second end of the backwash hole 30 is disposed at the front end of the equalization column 20, with the second end of the backwash hole 30 directly communicating with the outlet of the pump.

The working process of the centrifugal pump provided by the embodiment is as follows: the motor drives the main shaft to rotate, the main shaft drives the impeller to rotate, the liquid medium enters from the inlet, and after contacting with the impeller, the liquid medium enters the flow channel under the action of centrifugal force, then flows to the outlet and flows out from the outlet; meanwhile, the pressure of the liquid medium on the side of the impeller facing the outlet is higher than that on the side facing the inlet, so that the pressure of the outlet of the pump is higher than that of the inlet of the pump; at the moment, the liquid medium in the cavity can provide pressure towards the inlet for the impeller, and the impeller transmits the pressure to the main shaft, so that the main shaft has axial force which is parallel to the axis and faces the front end of the main shaft; meanwhile, the liquid medium at the outlet can enter the rear end of the balance column 20 through the preset gap between the balance sleeve 10 and the balance column 20, and the pressure is gradually reduced under the resistance of the preset gap in the flowing process of the liquid medium; the pressures at the front end and the rear end of the balance post 20 are unequal, namely the pressure at the front end is higher than that at the rear end; under the action of the pressure difference, the balance column 20 receives a hydraulic pressure towards the rear end of the main shaft, the direction of the hydraulic pressure is opposite to that of the axial force, and the hydraulic pressure acts on the main shaft, so that the hydraulic pressure can balance most of the axial force, and further the acting force between the main shaft and the pump body is reduced; when the main shaft rotates, the balance column 20 rotates together with the main shaft, so that the liquid medium in the back flushing hole 30 is sprayed out from the first end of the back flushing hole 30 under the action of centrifugal force, and the first end of the back flushing hole 30 is arranged close to the front end of the balance column 20, so that the liquid medium in the gap right opposite to the back flushing hole 30 flows to the front end of the balance column 20, and further, the particulate matters at the inlet of the gap are driven to flow out; as the main shaft continues to rotate, the backwash holes 30 continuously flush the gap near the forward end of the balance post 20 to flush particulate matter between the balance post 20 and the balance sleeve 10.

In addition, because the back washing holes 30 are formed in the balance column 20, the mass distribution of the balance column 20 is uneven, and the mass center W of the balance column is not coincident with the geometric center O of the balance column; in the process that the main shaft drives the balance post 20 to rotate, the main shaft is subjected to mass eccentric force f vertical to the axis due to uneven mass distribution of the balance post 20; along with the increase of the rotating speed of the main shaft, the mass eccentricity f force is gradually increased, the main shaft can generate elastic deformation, and then the gap between one side of the balance post 20 and the balance sleeve 10 is reduced, and the gap between the other side of the balance post is increased; on the other hand, when the balance column 20 rotates, the back washing hole 30 is equivalent to a micro booster pump, the reaction force of the liquid in the back washing hole 30 can generate a hydraulic eccentric force F on the balance column 20, and under the combined action of the mass eccentric force F and the hydraulic eccentric force F, one side of the balance column 20 is in contact with the inner wall of the balance sleeve 10 in the operation process, so that crystals, polymers and particles attached to the inner wall of the balance sleeve can be scraped off.

In the centrifugal pump provided by the embodiment, the balance sleeve 10 is arranged at the rear end of the pump, the balance column 20 is arranged in the balance sleeve 10 in a penetrating manner, and a preset gap is formed between the inner wall of the balance sleeve 10 and the outer wall of the balance column 20; the shaft hole is sleeved outside the rear end of the main shaft, the balance column 20 is connected with the main shaft through a stopping device, the stopping device can prevent the balance column 20 from moving along the direction parallel to the axis of the main shaft, and the stopping device can also prevent the balance column 20 from rotating relative to the main shaft; a back flushing hole 30 is formed in the side wall of the balance column 20 facing the front end of the pump, a first end of the back flushing hole 30 is communicated with the gap, and a second end of the back flushing hole 30 is used for being communicated with an outlet of the pump; when the main shaft rotates, the balance column 20 can be driven to rotate together, and when the balance column 20 rotates, the liquid medium in the back washing hole 30 is sprayed out from the first end of the back washing hole 30 under the action of centrifugal force, so that the particles between the balance column 20 and the balance sleeve 10 are washed away, and the particles are prevented from blocking the preset gap.

With continued reference to fig. 2. Specifically, the cross-sectional area of the first end of the backwash holes 30 is larger than the cross-sectional area of the second end of the backwash holes 30. So as to increase the cleaning area between the liquid medium sprayed from the first ends of the back washing holes 30 and the inner wall of the balance sleeve 10, and further enhance the washing effect on the preset gap. In addition, due to the small cross-sectional area of the second end of the back flushing hole 30, the liquid medium flowing into the back flushing hole 30 can be filtered, so that the particles are prevented from entering the back flushing hole 30.

With continued reference to fig. 2. Specifically, the shaft hole includes a first section 201 and a second section 202, the first section 201 is disposed toward the front end of the pump, the diameter of the first section 201 is larger than that of the second section 202, the second section 202 is connected with the main shaft through a stop device, and the second end of the backwashing hole 30 is located on the side wall of the first section 201. The phenomenon that the flowing direction of the liquid medium in the back washing hole 30 is changed and the flowing resistance of the liquid medium in the back washing hole 30 is large due to the fact that the second end of the back washing hole 30 is located at the front end of the balance column is avoided. Preferably, the first ends of the backwash holes 30 and the second ends of the backwash holes 30 may be arranged in the radial direction of the first section 201 of the balance column 20.

With continued reference to fig. 2. Specifically, a preset included angle β is formed between the axis of the backwash hole 30 and the end surface of the balance column 20. The length of the backwash holes 30 can be increased to increase the volume of liquid medium contained within the backwash holes 30.

Preferably, the preset included angle β is not limited in this embodiment, and a person skilled in the art can reasonably set the size of the preset included angle β according to an actual use condition; for example: the preset included angle β may be 45 °, 60 °, 75 °, etc. Further preferably, the axes of the back washing holes 30 and the axes of the shaft holes are respectively located in two planes, an included angle between the axes of the back washing holes 30 and the axes of the shaft holes is α, and α may be 45 °, 60 °, 75 °, and the like; to further increase the flushing effect of the backwash holes 30.

In other embodiments, the back flushing holes 30 may be multiple, and the back flushing holes 30 are spaced so that each back flushing hole 30 can spray liquid medium to the inner wall of the balancing sleeve 10 when the main shaft rotates, thereby enhancing the flushing effect on the gap between the balancing column 20 and the balancing sleeve 10. At this time, it is necessary to ensure that the back flushing holes 30 are unevenly arranged along the axial direction of the balancing column 20, so that the mass center W of the balancing column does not coincide with the geometric center O of the balancing column, and further, under the action of the mass eccentricity F and the hydraulic eccentric force F when the main shaft rotates, the main shaft elastically deforms, so that the balancing column 20 contacts with the side wall of the balancing sleeve 10, and the particles attached to the balancing sleeve 10 are scraped off.

With continued reference to fig. 2. Specifically, a sealing groove 204 is formed in a sidewall of the second section 202, and a sealing ring is installed in the sealing groove 204. So as to enhance the sealing performance between the side wall of the second section 202 and the main shaft and avoid the liquid medium in the cavity from overflowing through the gap between the main shaft and the side wall of the second section 202.

Preferably, the sealing ring is not limited in this embodiment, and the sealing ring may be a rubber ring. The outer side face of the rubber ring is connected with the sealing groove 204, and the inner wall of the rubber ring is connected with the spindle.

With continued reference to fig. 2. Specifically, the sealing groove 204 is plural, and the plural sealing grooves 204 are arranged at intervals along the axis of the balance post 20. To further enhance the seal between the main shaft and the second section 202.

With continued reference to fig. 4. Specifically, the balance sleeve 10 is provided with a turbulence groove 102. The turbulence grooves 102 can form turbulence at the inlet of the preset gap between the balance sleeve 10 and the balance post 20, thereby clearing the blockage of larger particles.

In order to cause the liquid medium to flow through the predetermined gap, the pressure drop is large, and thus a large hydraulic pressure is generated. The preset gap is generally set to be small, so that when the balance column 20 and the main shaft rotate together at a high speed, more heat is generated by friction between the balance column 20 and a liquid medium in the gap, the balance sleeve 10 is easily heated, and when the temperature of the balance sleeve 10 is too high, the balance sleeve 10 and the balance column 20 are bonded; the axial force balance fails.

Preferably, the present embodiment does not limit the position of the turbulent flow groove 102, such as: the turbulence grooves 102 may be arranged on the side of the balancing sleeve 10 facing the motor end, so that the turbulence grooves 102 are in contact with the liquid medium in the cavity, thereby enhancing the cleaning effect.

Preferably, the turbulence groove 102 is provided at an end of the balance sleeve 10 near the front end of the pump. Namely, the turbulence groove 102 is arranged at the front end of the balance sleeve 10, so as not to influence the sealing performance of the balance sleeve 10 or the liquid medium flow in the cavity by the turbulence groove 102.

With continued reference to fig. 2. Further preferably, the turbulence grooves 102 are plural, and the plurality of turbulence grooves 102 are arranged at intervals along the circumference of the balancing sleeve 10. To further enhance the heat dissipation effect of the balance sleeve 10. Specifically, heat dissipation flanges may be formed on the side walls of the rear end of the balance sleeve 10, and the turbulence grooves 102 are all formed on the heat dissipation flanges, so as to prevent the strength of the balance sleeve 10 from being affected by the turbulence grooves 102.

There is also provided in other embodiments a delivery apparatus comprising: comprising a delivery conduit and a centrifugal pump as described above, the inlet of the centrifugal pump being adapted to communicate with the inlet tank and the outlet of the centrifugal pump communicating with the delivery conduit. And conveying the liquid medium in the inlet tank to a processing factory through a conveying pipeline, and further processing the liquid medium.

Wherein, the centrifugal pump includes: a main shaft, an impeller, a balance sleeve 10 and a balance post 20; the main shaft extends from the front end to the rear end of the pump, and the impeller is arranged on the main shaft; the balance sleeve 10 is arranged at the rear end of the pump, the balance column 20 penetrates through the balance sleeve 10, and a preset gap is formed between the inner wall of the balance sleeve 10 and the outer wall of the balance column 20; the balance post 20 is provided with a shaft hole, and the rear end of the main shaft extends into the shaft hole; the balance post 20 is connected with the main shaft through a stopping device, the stopping device is used for preventing the balance post 20 from moving along the direction parallel to the axis of the main shaft, and the stopping device is also used for preventing the balance post 20 from rotating relative to the main shaft; the balance column 20 is provided with a back flushing hole 30, a first end of the back flushing hole 30 is communicated with the gap, and a second end of the back flushing hole 30 is communicated with an outlet of the pump.

Specifically, the shape of the impeller is not limited in this embodiment, and it is only necessary to ensure that when the impeller rotates, the liquid medium on the impeller can enter the flow channel in the cavity under the action of the centrifugal force, and then enter the outlet of the pump through the flow channel. Preferably, the impeller may be provided in plurality, and the plurality of impellers are arranged at intervals in the axial direction of the main shaft to increase the outlet pressure of the pump. In addition, the embodiment does not limit the connection mode between the impeller and the main shaft, as long as it is ensured that the main shaft can drive the impeller to rotate when the main shaft rotates, and the impeller cannot move along the axial direction of the main shaft due to the axial force; for example: the impeller can be connected with the main shaft in a key connection mode, and in addition, positioning sleeves can be arranged at two ends of the impeller so as to prevent the impeller from moving along the axial direction; a first shaft shoulder is arranged on the main shaft, the front end of the first positioning sleeve abuts against the first shaft shoulder, the rear end of the first positioning sleeve abuts against the front end of the impeller, the rear end of the impeller abuts against the front end of the second positioning sleeve, and the rear end of the second positioning sleeve abuts against the front end of the balance column 20, so that the impeller is axially positioned; through set up first keyway on the main shaft and set up on the impeller with first keyway complex second keyway, the parallel key pierces through respectively in first keyway and second keyway, realizes that the transmission of impeller and main shaft is connected.

Specifically, the rear end of the pump body is closed by a closing portion constituted by the balance sleeve 10, the balance post 20, and the main shaft. In this embodiment, the connection manner between the balance sleeve 10 and the pump body is not limited, as long as the balance sleeve 10 can be prevented from rotating, and the liquid medium in the cavity can be prevented from overflowing from between the balance sleeve 10 and the pump body; for example: the outer wall of the balance sleeve 10 is provided with external threads, the inner wall of the rear end of the cavity is provided with internal threads, and the internal threads and the external threads are matched to realize the connection between the balance sleeve 10 and the pump body; or, a connecting flange is formed on the outer side of the front end of the balance sleeve 10, a mounting hole is formed on the connecting flange, a mounting threaded hole is correspondingly formed on the rear end face of the pump body, and a mounting bolt penetrates through the mounting hole and then is screwed into the mounting threaded hole, so that the balance sleeve 10 is connected with the pump body; in order to enhance the sealing performance between the pump body and the balance sleeve 10, a sealing gasket may be disposed between the balance sleeve 10 and the rear end face of the pump body, and the sealing gasket may be a rubber gasket. Of course, a connecting flange may be formed on the rear end side wall of the balance sleeve 10, the balance sleeve 10 before the connecting flange is inserted into the cavity, and at this time, in order to enhance the sealing performance between the pump body and the balance sleeve 10, a sealing ring may be provided on the side wall of the balance sleeve 10, and the sealing ring may be a rubber ring.

Preferably, a pressure balance groove 101 is formed in the inner wall of the balance sleeve 10, the pressure balance groove 101 may be an annular groove, and the pressure balance groove 101 may store a liquid medium therein so as to balance the pressure of the liquid medium in the preset gap.

The working process of the centrifugal pump provided by the embodiment is as follows: the motor drives the main shaft to rotate, the main shaft drives the impeller to rotate, the liquid medium enters from the inlet, and after contacting with the impeller, the liquid medium enters the flow channel under the action of centrifugal force, then flows to the outlet and flows out from the outlet; meanwhile, the pressure of the liquid medium on the side of the impeller facing the outlet is higher than that on the side facing the inlet, so that the pressure of the outlet of the pump is higher than that of the inlet of the pump; at the moment, the liquid medium in the cavity can provide pressure towards the inlet for the impeller, and the impeller transmits the pressure to the main shaft, so that the main shaft has axial force which is parallel to the axis and faces the front end of the main shaft; meanwhile, the liquid medium at the outlet can enter the rear end of the balance column 20 through the preset gap between the balance sleeve 10 and the balance column 20, and the pressure is gradually reduced under the resistance of the preset gap in the flowing process of the liquid medium; the pressures at the front end and the rear end of the balance post 20 are unequal, namely the pressure at the front end is higher than that at the rear end; under the action of the pressure difference, the balance column 20 receives a hydraulic force towards the rear end of the main shaft, the direction of the hydraulic force is opposite to that of the axial force, and the hydraulic force acts on the main shaft, so that the hydraulic force can balance most of the axial force, and further the acting force between the main shaft and the pump body is reduced; when the main shaft rotates, the balance column 20 rotates together with the main shaft, so that the liquid medium in the back flushing hole 30 is sprayed out from the first end of the back flushing hole 30 under the action of centrifugal force, and the first end of the back flushing hole 30 is arranged close to the front end of the balance column 20, so that the liquid medium in the gap right opposite to the back flushing hole 30 flows to the front end of the balance column 20, and further, the particulate matters in the gap are driven to flow out; as the main shaft continues to rotate, the backwash holes 30 continuously flush the gap near the forward end of the balance post 20 to flush particulate matter between the balance post 20 and the balance sleeve 10.

In addition, because the back washing holes 30 are formed in the balance column 20, the mass distribution of the balance column 20 is uneven, and the mass center W of the balance column is not coincident with the geometric center O of the balance column; in the process that the main shaft drives the balance post 20 to rotate, the main shaft is subjected to mass eccentric force f vertical to the axis under the action of mass eccentricity; along with the increase of the rotating speed of the main shaft, the mass eccentricity f force is gradually increased, the main shaft can generate elastic deformation, and then the gap between one side of the balance post 20 and the balance sleeve 10 is reduced, and the gap between the other side of the balance post is increased; on the other hand, when the balance column 20 rotates, the back washing hole 30 is equivalent to a micro booster pump, the reaction force of the liquid in the back washing hole 30 can generate a hydraulic eccentric force F on the balance column 20, and under the combined action of the mass eccentric force F and the hydraulic eccentric force F, one side of the balance column 20 is in contact with the inner wall of the balance sleeve 10 in the operation process, so that crystals, polymers and particles attached to the inner wall of the balance sleeve can be scraped off.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A centrifugal pump, comprising: the balance mechanism comprises a main shaft, an impeller, a balance sleeve and a balance column; the main shaft extends from the front end to the rear end of the pump, and the impeller is arranged on the main shaft; the balance sleeve is arranged at the rear end of the pump, the balance column penetrates through the balance sleeve, and a preset gap is formed between the inner wall of the balance sleeve and the outer wall of the balance column; the balance column is provided with a shaft hole, and the rear end of the main shaft extends into the shaft hole; the balance column is connected with the main shaft through a stopping device, the stopping device is used for preventing the balance column from moving along the direction parallel to the axis of the main shaft, and the stopping device is also used for preventing the balance column from rotating relative to the main shaft; the balance column is provided with a back flushing hole, a first end of the back flushing hole is communicated with the gap, a second end of the back flushing hole is communicated with an outlet of the pump, and the back flushing hole is used for enabling the mass center and the geometric center of the balance column not to coincide.

2. The centrifugal pump of claim 1, wherein a cross-sectional area of said back flushing port first end is greater than a cross-sectional area of said back flushing port second end.

3. The centrifugal pump of claim 1 wherein said shaft bore includes a first section proximate the forward end of the pump and a second section distal from the forward end of the pump, and wherein said first section has a diameter greater than a diameter of said second section, and wherein said stop means is disposed in said second section, and wherein said second end of said backwash bore is located on an inner surface of said first section.

4. The centrifugal pump of claim 3 wherein the axis of said backwash holes is at a predetermined angle to the end face of said balancing post.

5. The centrifugal pump of claim 3, wherein a seal groove is formed in a sidewall of the second section, and a seal ring is installed in the seal groove.

6. The centrifugal pump of claim 5, wherein said seal groove is plural and is spaced along an axis of said balancing post.

7. The centrifugal pump according to any one of claims 1 to 6, wherein the balance sleeve is provided with a turbulence groove.

8. The centrifugal pump of claim 7 wherein said turbulence grooves are disposed at an end of said balance sleeve adjacent the forward end of the pump.

9. The centrifugal pump of claim 8 wherein said plurality of turbulators are spaced circumferentially of said balance sleeve.

10. A delivery apparatus comprising a delivery conduit and a centrifugal pump as claimed in any one of claims 1 to 8, the inlet of the centrifugal pump being adapted to communicate with an inlet tank and the outlet of the centrifugal pump communicating with the delivery conduit.