CN113357159B

CN113357159B - Self-suction type composite shield pump based on direct-current permanent magnet motor

Info

Publication number: CN113357159B
Application number: CN202110756107.9A
Authority: CN
Inventors: 陈荣国
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-07-05
Filing date: 2021-07-05
Publication date: 2022-05-31
Anticipated expiration: 2041-07-05
Also published as: CN113357159A

Abstract

The invention discloses a self-suction type composite shield pump based on a direct-current permanent magnet motor. The inlet of a pump is connected with the inlet of an ejector, the diffusion section of the ejector is connected with the inlet of a centrifugal end, the outlet of the centrifugal end is communicated with the inlet of a buffer pressurizing cavity, the outlet of the buffer pressurizing cavity is communicated with a gas-liquid separation chamber, and the gas-liquid separation chamber is communicated with the outlet of the pump; the buffer pressurizing cavity is used for rapidly decelerating and pressurizing the high-speed pressurized fluid at the outlet of the centrifugal end; in the exhaust self-priming stage, the flow velocity of gas-liquid mixed fluid is reduced, and meanwhile, the bubble breakage is reduced; in the non-exhaust stage, the flow resistance is reduced, the pressure loss is reduced, and simultaneously the buffer pressurization of the fluid at the outlet of the centrifugal end is realized. The invention adopts the direct current permanent magnet motor to combine the ejector and the shield pump, so that the shield pump has the characteristics of strong self-absorption and good hydraulic property, the spatial position and the internal structure of the buffer pressurizing cavity are skillfully arranged, and the technical problem of difficult gas-liquid separation caused by serious bubble breakage in the composite shield pump at high rotating speed is effectively solved.

Description

Self-suction type composite shield pump based on direct-current permanent magnet motor

Technical Field

The invention belongs to the field of fluid machinery, and particularly relates to a self-suction type composite shield pump based on a direct-current permanent magnet motor.

Background

In various pump products, the shielding pump is widely applied and popularized in the aspects of chemical engineering, energy, hydraulic engineering and structural engineering by virtue of the special characteristics of a sealing structure, no leakage risk, high reliability and the like, and particularly plays a key technical support role in the aspect of transporting fluid media such as precious, flammable and explosive, radioactive, corrosive and the like. The canned motor pump has unique structure, can seal the motor and the pump body part in a certain canned motor pump chamber, and pumping medium fills the pump chamber inner wall, and the overall structure does not have movable sealing member, and the operation is very safe. Meanwhile, the circulating medium can effectively solve the problem of motor temperature rise, a motor cooling fan is not needed, the noise of a shield pump is reduced, and the circulating medium has a high application value in the scenes with mute requirements of household appliances, hospital detection instruments and the like.

The canned motor pump is a non-dynamic canned motor pump, the pump and the driving motor are sealed in a canned motor pump cavity filled with pumped medium, the canned motor pump body only has static seal, and a motor wire group is used for providing a rotating magnetic field and driving a rotor. Although many of the canned motor pumps have many advantages, most canned motor pumps do not have a self-priming function, and in order to achieve self-priming, the technical scheme that the existing ejector structure of the injection pump is directly adopted and a conventional asynchronous motor is adopted to drive a centrifugal impeller is adopted, but the multi-primary ejector structure causes the problems of reduced energy conversion rate, increased temperature of the asynchronous motor and the like, and the efficiency of the canned motor pump is seriously reduced. The fluid after the injection acceleration is further accelerated due to the strong centrifugation of the centrifugal impeller, so that the gas-liquid separation is easy to lose efficacy, and the self-priming function of the canned motor pump cannot be realized; in order to compensate for the performance reduction of the composite canned motor pump caused by efficiency loss, a larger-power motor and a larger-diameter impeller are generally required to be replaced, and the composite canned motor pump is difficult to effectively popularize in engineering.

Disclosure of Invention

Aiming at the problems that the existing canned motor pump does not have self-suction or has weak suction and low energy efficiency, the invention aims to provide a self-suction composite canned motor pump based on a direct-current permanent magnet motor, which has comprehensive working performance such as self-suction capacity, flow, lift, suction lift and the like, extremely high safety and compact structure.

In order to achieve the purpose, the invention adopts the technical scheme that:

the invention comprises a pump inlet, an ejector, a centrifugal end, a buffer pressurizing cavity, a gas-liquid separation chamber and a pump outlet, wherein the pump inlet is connected with the inlet of the ejector;

the centrifugal end comprises a direct current permanent magnet motor, a centrifugal impeller and a centrifugal water pressurizing chamber, the centrifugal impeller is positioned in the centrifugal water pressurizing chamber and is connected with a rotor of the direct current permanent magnet motor, and the rotor of the direct current permanent magnet motor is isolated from a stator through a shielding sleeve; the maximum rotating speed of the direct current permanent magnet motor at least reaches 3600 revolutions per minute;

the buffer pressurizing cavity is used for rapidly decelerating and pressurizing the high-speed pressurized fluid at the outlet of the centrifugal end; in the exhaust self-priming stage, the flow velocity of gas-liquid mixed fluid is reduced, and meanwhile, the bubble breakage is reduced; in the non-exhaust stage, the flow pressure loss is reduced, and simultaneously the buffering pressurization of the fluid at the outlet of the centrifugal end is realized.

Further, the outlets of the buffer pressurizing cavities are distributed along the circumferential direction or the radial direction in a plane, or the pores are arranged in space.

Furthermore, the buffer pressurizing cavity is a porous laminate series structure, a porous space structure, a porous medium filling structure, a single circuitous flow passage combined structure or a structure combined by a plurality of circuitous flow passages

Furthermore, a fixed or rotary guide vane is additionally arranged in the buffering pressurization cavity of the multi-pore laminate series structure, or an inlet and an outlet of the buffering pressurization cavity are set as rotatable guide vanes.

Further, the buffer pressurizing cavity and the centrifugal impeller are distributed up and down or concentrically. When the centrifugal end is distributed up and down, the outlet of the centrifugal end is communicated with the buffer pressurizing cavity through the flow guide cavity.

Furthermore, a check valve is arranged at the inlet of the nozzle of the ejector, when the self-priming stage of the composite shield pump is finished, the check valve is closed under the driving of the internal and external pressure difference of the ejector, liquid in the gas-liquid separation chamber cannot enter the ejector through the nozzle, and the internal circulation flow of the pump is stopped.

Furthermore, at least one buffer pressurizing cavity, at least one centrifugal end and at least one centrifugal end outlet are formed.

The invention also provides a combined self-suction type composite shield pump which comprises the self-suction type composite shield pump and at least one centrifugal pump, wherein inlets of the self-suction type composite shield pump and the centrifugal pump are connected in parallel, and outlets of the self-suction type composite shield pump and the centrifugal pump are connected in parallel.

By adopting the technical scheme, the invention has the beneficial effects that:

1. compare the big impeller of traditional asynchronous machine cooperation and the drawback that the ejector can only solve the compound pump from inhaling the performance and can't solve efficiency, direct current permanent-magnet machine makes things convenient for compound canned motor pump intelligent control and performance monitoring, high rotational speed centrifugation leaflet wheel utilizes the form of high rotational speed cooperation direct current permanent-magnet machine, and complete machine power is little when reaching the performance equivalent with traditional compound canned motor pump performance, and operating efficiency is high, improves the water pump efficiency and compromises performance and security simultaneously, and easily realizes miniaturation, has high market value.

2. The direct-current permanent magnet motor is combined with the characteristics of the ejector and the shielding pump, so that the shielding pump has the functions of strong self-absorption, good hydraulic characteristic, energy conservation and cavitation resistance, the spatial position and the internal structure of the buffer pressurizing cavity are ingeniously arranged, and the technical problem that the gas-liquid separation is difficult due to the fact that bubbles in the composite shielding pump are broken seriously at a high rotating speed is effectively solved.

3. The buffer pressurizing cavity has various structural forms, convenient material taking and low cost ratio, but can greatly improve the gas-liquid separation capacity in the pump and realize the strong self-absorption performance of the canned motor pump.

4. Fixed or rotary type stator can be add to the buffering pressure boost intracavity, perhaps changes buffering pressure boost chamber structure, imports and exports the buffering chamber and sets up to the rotary type stator, further strengthens buffering pressure boost effect.

5. The centrifugal end is independently provided with a centrifugal impeller, a centrifugal pumping chamber and a direct-current permanent magnet motor, and according to different application requirements, one or more pumps are connected in parallel at the inlet end of the pump, so that the self-priming composite shield pump with higher performance can be combined as required.

6. A check valve or an elastic separation blade can be arranged at the inlet position of the nozzle of the ejector, when the self-priming working stage is carried out, the check valve or the elastic separation blade is in an open state, and liquid in the gas-liquid separation chamber flows into the diffusion section of the ejector through the nozzle of the ejector, so that the gas-liquid mixing process is finished; during the working phase, check valve or elasticity separation blade are closed, and liquid in the gas-liquid separation chamber can't get into the sprayer through the nozzle position again, can further promote the working phase efficiency.

7. The composite shield pump can balance the pump performance and the specific requirements of gas-liquid separation according to actual needs, and the number of the buffer pressurizing cavities is not limited to one.

8. The self-priming centrifugal pump structure keeps the characteristics of a shield pump mechanism without dynamic seal, is suitable for pumping corrosive, toxic, harmful and flammable media, and has extremely high safety by adopting a low-voltage direct-current permanent magnet motor.

9. The self-priming composite canned motor pump comprises an ejector, a centrifugal impeller, a centrifugal pumping chamber, a buffer pressurizing cavity, a gas-liquid separation chamber and the like, has compact structure, small volume and high integration level, skillfully combines the advantages of canned motor pumps and jet pumps, and can cover the requirements of various civil pumps and industrial pumps at present.

Drawings

FIG. 1 is a schematic longitudinal sectional view of a composite canned motor pump configuration;

FIG. 2 is a sectional view of a part of the structure of the composite canned motor pump;

FIG. 3 is a schematic overall view of a compound canned motor pump;

FIG. 4a is a schematic flow direction cross-sectional view of a flow guide cavity;

fig. 4b is a schematic partial cross-sectional view of a flow guide cavity;

FIG. 5 is a schematic sectional view of a primary buffer chamber of a buffer pressurizing chamber with a multi-pore laminate series structure;

FIG. 6 is a schematic sectional view of a secondary buffer chamber of a buffer pressurizing chamber with a multi-pore laminate series structure;

FIG. 7a is a schematic diagram of a configuration in which the buffer plenum fill media is spherical particles;

FIG. 7b is a schematic view of a filling structure of a buffer pressurizing cavity with a wire-mesh multi-gap laminate;

FIG. 7c is a schematic view of a buffer plenum employing an irregular particle multi-void fill configuration;

FIG. 8 is a schematic longitudinal sectional view of a compound pump injector;

FIG. 9a is a schematic diagram of a centrifuge tip configuration;

FIG. 9b is a schematic structural diagram of a DC permanent magnet motor;

FIG. 10 is a flow diagram of a self-priming stage of a compound canned motor pump;

FIG. 11 is a schematic flow diagram of a composite canned motor pump at an operating stage;

FIG. 12 is a schematic diagram of an injector nozzle inlet check valve open configuration;

FIG. 13 is a schematic view of the injector nozzle inlet check valve closed configuration;

FIG. 14 is a schematic view of the structure of the injector nozzle inlet in an open state of a check elastic baffle;

FIG. 15 is a schematic view of the injector nozzle inlet check spring flap in a closed state;

FIG. 16 is a schematic view of the concentric arrangement of the buffer plenum and the centrifugal end;

FIG. 17 is a schematic view of the internal flow of the buffer plenum and the centrifugal end concentrically arranged;

fig. 18 is a schematic diagram of a parallel structure of a compound canned motor pump and a centrifugal pump.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the following will make clear and complete description of the technical solution of the present invention with reference to the drawings in the present application, and it is obvious that the description is only a part of the embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention without making creative efforts, shall fall within the protection scope of the invention.

The composite shield pump comprises a pump inlet, an ejector, a centrifugal end, a buffer pressurizing cavity, a gas-liquid separation chamber and a pump outlet; the ejector consists of an ejector inlet, a guide pipe, a nozzle, a throat pipe and a diffusion section, wherein the nozzle inlet of the ejector can be additionally provided with a check valve or an elastic baffle plate; the centrifugal end comprises a centrifugal impeller, a centrifugal guide vane, a centrifugal pumping chamber and a direct current permanent magnet motor, and the maximum rotating speed of the direct current permanent magnet motor at least reaches 3600 revolutions per minute; the inlet of the pump is connected with the inlet of the ejector positioned in the gas-liquid separation chamber, the diffusion section of the ejector is connected with the inlet of the centrifugal end, the outlet of the centrifugal end is communicated with the inlet of the buffer pressurizing cavity, the outlet of the buffer pressurizing cavity is communicated with the gas-liquid separation chamber, and the gas-liquid separation chamber is communicated with the outlet of the pump; the centrifugal impeller is connected with the motor rotor, the motor rotor is isolated from the stator through the shielding sleeve, and the whole pump is free of dynamic seal.

The buffer pressurizing cavity is a flow channel for rapidly decelerating and pressurizing the high-speed pressure fluid at the outlet of the centrifugal end, so that the flow speed of the gas-liquid mixed fluid is effectively reduced and the bubble breakage is reduced at the exhaust self-suction stage, and the buffer pressurizing of the fluid at the outlet of the centrifugal end is realized at the non-exhaust stage while the flow resistance is effectively reduced and the pressure loss is reduced.

The buffer pressurizing cavity is relatively independent from the gas-liquid separation chamber, and only the outlet of the buffer pressurizing cavity is connected with the gas-liquid separation chamber.

The outlets of the buffer pressurizing cavity can be distributed in a plurality of ways such as arrangement of pores along the circumferential direction, the radial direction or a certain space region, and the number of the outlets is not less than one.

The buffer pressurizing cavity can be a flow channel which can simultaneously reduce bubble breakage and efficiently buffer pressurizing, such as a porous single-layer plate, a porous plate series structure, an irregular porous plane, a porous space structure, a porous medium filling structure, a single or a structure formed by combining a plurality of circuitous flow channels and the like.

Fixed or rotary guide vanes can be additionally arranged in the buffering pressurization cavity of the multi-pore laminate series structure, or the inlet and the outlet of the buffering pressurization cavity are set as rotatable guide vanes.

The buffer pressurizing cavity and the centrifugal impeller are distributed up and down or concentrically. When the centrifugal end is distributed up and down, the outlet of the centrifugal end is communicated with the buffer pressurizing cavity through the flow guide cavity.

The direct current permanent magnet motor mainly comprises a shielding sleeve, a stator, a rotor and a motor shaft, wherein the shielding sleeve isolates the motor rotor from the stator in a static sealing mode, and the rotor and an impeller directly run in a working medium.

A check valve or an elastic retaining sheet can be arranged at the inlet of the nozzle of the ejector, when the self-priming stage of the composite shield pump is finished, the check valve is closed under the driving of the internal and external differential pressure of the ejector, liquid in the gas-liquid separation chamber can not enter the ejector through the nozzle, the internal circulation flow of the pump is stopped, and the efficiency is improved.

At least one buffer pressurizing cavity, at least one centrifugal end and at least one centrifugal end outlet.

The ejector inlets can be simultaneously communicated with one or more pump inlets to form a parallel pump set, exhaust is not influenced in a self-suction exhaust stage, the performance of the pump is improved in a non-self-suction normal working stage, and different application requirements are met.

The working process of the invention is as follows:

when the self-priming composite canned motor pump is in a self-priming exhaust stage, the pump and the direct-current permanent magnet motor are sealed in a composite canned motor pump cavity filled with pumped media, and pre-filled fluid is stored in the ejector, the centrifugal end, the buffer pressurizing cavity and the gas-liquid separation chamber. Compared with the traditional asynchronous motor, the direct-current permanent magnet motor with higher safety and efficiency is adopted, and the direct-current permanent magnet motor drives fluid to obtain higher-speed working fluid, so that the gas-liquid separation of the composite shield pump in the self-suction stage is more difficult under the condition that a centrifugal impeller and a pump cavity are reduced, the high-speed impeller is easily subjected to gas binding, and the self-suction function of the composite shield pump is difficult to realize. Specifically, on one hand, the bubbles are easy to collide with the wall surface or an impeller and break under the high-speed flowing state, and then cannot freely float up and leave the water body in the pump; on the other hand, the impeller rotating at a high speed forms a very strong circumferential shear, bubbles are more easily broken in the impeller, and are clamped by the rapid reduction of the size of the bubbles and the high-speed flow in the pump, so that the bubbles float upwards and leave the water body more difficultly, the gas-liquid separation is almost ineffective, and the composite shield pump cannot successfully finish self-suction. Therefore, in order to avoid the problem of gas-liquid separation caused by the high rotating speed of the direct current permanent magnet motor, the fluid mixed by the ejector is guided out by the centrifugal water pressurizing chamber and enters the buffer pressurizing cavity for buffer pressurizing after being driven by the centrifugal impeller at a high speed, so that bubbles in the pump in the self-priming stage can float freely for a longer time to complete gas-liquid separation.

The buffer pressurizing cavity with the multi-pore double-layer plate series structure is provided with a certain arrangement of buffer fins, high-speed fluid is guided by the buffer fins of the primary buffer cavity, the speed of the high-speed fluid is rapidly reduced, the high-speed fluid is discharged from an outlet of the primary buffer cavity, the high-speed fluid flows into the secondary buffer cavity, the fluid medium is further decelerated, and the fluid medium is discharged from an outlet of the secondary buffer cavity. Then enters a gas-liquid separation chamber or enters a next-stage buffer pressurizing cavity. The invention effectively converts the kinetic energy of the fluid obtained by driving the high-speed centrifugal impeller into potential energy in a multi-stage buffering mode, completes the speed reduction and pressurization of the working medium, reduces the hydraulic loss and simultaneously meets the requirements of gas-liquid separation.

The fluid flowing out of the outlet of the buffer pressurizing cavity directly enters the gas-liquid separation chamber, the speed of a fluid medium in the gas-liquid separation chamber is obviously reduced due to the functions of flow guiding and the buffer pressurizing cavity, the working fluid is fully retained in the gas-liquid separation chamber, and the gas-liquid separation of the compound pump is realized. If a buffer pressurizing cavity is not arranged, high-speed fluid after the centrifugal impeller is driven by the direct-current permanent magnet motor cannot be sufficiently decelerated, so that gas-liquid separation cannot be completed, the air-bound phenomenon of the impeller is dominant, and self-priming failure can be directly caused.

Meanwhile, in order to keep the compact structure and the better buffering effect of the composite canned motor pump, the secondary buffer cavity and the primary buffer cavity of the buffering pressurization cavity can be kept concentric, and the outlets of the secondary buffer cavity are distributed (uniformly or non-uniformly) along the circumferential direction, the radial direction or in a certain area of the cover plate of the secondary buffer cavity. In addition, the buffer pressurizing cavity and the centrifugal end can be concentrically distributed, and the compactness of the whole structure can be effectively improved.

When the self-priming composite shield pump is in an actual working stage, fluid to be pumped in a pump inlet pipeline is sucked into the ejector along the composite pump inlet, and high-speed working fluid ejected from the nozzle enters a centrifugal end after accelerated mixing through the ejector throat pipe and decelerated pressurization through the diffusion section; then, the part of the fluid is accelerated and pressurized by the centrifugal impeller to obtain higher speed and pressure, and then is discharged from the centrifugal pressurizing water chamber, enters the buffer pressurizing cavity for speed reduction and pressurization, and is discharged from an outlet of the buffer pressurizing cavity, so that the speed reduction and pressurization of the working medium are realized.

The fluid flowing out of the buffer pressurizing cavity enters the gas-liquid separation chamber, and a part of the fluid is discharged through the outlet of the composite pump to finish pumping the fluid; and the other part of the pressurized fluid which is not discharged outside the pump continuously and circularly flows in the gas-liquid separation chamber to provide working fluid for the nozzle of the ejector, and the strong negative pressure formed near the outlet of the nozzle continuously sucks the fluid to be pumped at the inlet of the pump, so that the process is repeated, and the normal pumping of the fluid to be pumped by the composite shielding pump is realized. In the process, the buffer pressurizing cavity can effectively reduce the flow resistance and reduce the pressure loss, and simultaneously realize the buffer pressurizing of the fluid at the outlet of the centrifugal end (if the fluid with too high speed passes through the buffer pressurizing cavity, the kinetic energy is converted into pressure potential energy, if the buffer pressurizing cavity is not arranged, the energy dissipation can be caused by strong impact, and the flow resistance can be reduced by reducing the speed, namely, the energy dissipation is reduced).

As an improvement, a check valve or an elastic baffle can be arranged at the inlet position of a nozzle of the ejector, when a self-priming working stage begins, only pre-filled fluid circulates in a pump, continuous supplement of fluid to be pumped is avoided, the pressure difference between two sides (the inside of the ejector and the gas-liquid separation chamber) of the check valve or the elastic baffle is small, the check valve or the elastic baffle is in an open state under the action of spring elasticity, the elasticity of the elastic baffle or electromagnetic force, and liquid in the gas-liquid separation chamber flows into a throat of the ejector through the nozzle of the ejector, so that a gas-liquid mixing process is completed; along with the deepening of the self-priming stage, the pre-filled fluid in the pump continuously acts in the processes of accelerating and pressurizing through the ejector, driving to do work through the centrifugal impeller, decelerating and pressurizing through the buffer structure and the like, the pressure difference between two sides of the structure such as the check valve or the elastic retaining sheet is continuously increased until the self-priming stage is finished, and the check valve overcomes the action of the elastic force or the electromagnetic force of the spring under the action of larger pressure difference and enters a closed state. At this time, the liquid in the gas-liquid separation chamber cannot enter the ejector through the nozzle position any more, and the internal circulation of the fluid in the pump is stopped. In the self-priming stage, the high-speed fluid flowing in from the nozzle and the strong negative pressure caused by the diffusion section form an effective entrainment effect on the gas in the guide pipe, and the fluid is decelerated and pressurized under the action of the buffer structure to complete the gas-liquid separation and realize the self-priming function of the composite shield pump; during the working stage, the liquid in the gas-liquid separation chamber does not flow back to the position of the nozzle any more, and the liquid which completes the work is directly discharged through the outlet of the composite shielding pump. The self-priming function is realized by starting or stopping the working fluid at the inlet of the nozzle, and the internal circulation of the actual working stage is stopped, so that the hydraulic efficiency of the pump is improved powerfully.

The invention adopts the direct current permanent magnet high-speed motor, the small-size direct current motor is adopted to drive the smaller centrifugal impeller due to high rotating speed, the whole size of the pump body is small, the efficiency problem of the conventional asynchronous motor is greatly improved by the direct current permanent magnet motor, the rotating speed of the direct current motor is improved (the highest rotating speed is more than 3600rpm and even can reach 10000 rpm), and the design of the ejector, the diversion and the buffer structure is matched, so that the self-priming function of the composite canned motor pump is realized, and meanwhile, the higher hydraulic efficiency is obtained. Meanwhile, compared with the traditional asynchronous motor, the direct current permanent magnet motor has extremely high safety, when the direct current safe voltage of 36V or below is adopted, even if the direct current safe voltage leaks electricity, the direct current safe motor has no life threat to human bodies, and the composite shield pump has small integral size, compact structure and wide market application prospect.

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

as shown in fig. 1, 2 and 3, the present embodiment specifically includes a pump inlet 1, an ejector, a centrifugal end, a diversion cavity 10, a buffer pressurizing cavity 11, a gas-liquid separation chamber 12, a composite shield pump casing 14 and a pump outlet 13, the ejector is composed of an ejector inlet 2, a conduit 3, a nozzle 4, a throat 5 and a diffuser section 6 (as shown in fig. 8), the centrifugal end specifically includes a centrifugal impeller 7, a centrifugal guide vane 8, a centrifugal pressurizing water chamber 15 and a direct current permanent magnet motor 9 (as shown in fig. 9a and 9 b), wherein a motor rotor 93 is isolated from a stator 92 by a shield sleeve 91, the motor rotor 93 is fixedly connected with the centrifugal impeller 7 by a motor shaft 94, the direct current permanent magnet motor is provided with a motor casing 95, and the pump body is sealed without moving. The inlet of the pump is connected with the inlet of the ejector, the diffusion section of the ejector is connected with the inlet of the centrifugal end, the outlet of the centrifugal end is communicated with the inlet of the buffer pressurizing cavity, the outlet of the buffer pressurizing cavity is communicated with the gas-liquid separation chamber, and the gas-liquid separation chamber is communicated with the outlet of the pump. The buffer pressurizing cavity and the centrifugal impeller are distributed up and down or concentrically (figure 16). When the centrifugal pump is distributed up and down, the outlet of the centrifugal end is connected with the buffer pressurizing cavity through the flow guide cavity.

As shown in fig. 4a and 4b, the diversion cavity 10 includes a diversion cavity bottom plate 101, a diversion cavity 102, and a diversion cavity enclosure plate 103; as shown in FIG. 5, the buffer pressurizing cavity of the multi-pore laminate series structure comprises a primary buffer cavity and a secondary buffer cavity, and the primary buffer cavity and the secondary buffer cavity are concentric. The primary buffer cavity comprises primary buffer cavity inlets 11-100, buffer fins 11-101, primary buffer bottom plates 11-102, primary buffer cavity outlets 11-103, primary buffer cavity outlet cover plates 11-104 and primary buffer cavities 11-105; the secondary buffer chamber 11-2 includes a secondary buffer chamber 11-201, a secondary buffer chamber cover plate 11-202 and a secondary buffer chamber outlet 11-203 (shown in fig. 6).

As shown in fig. 7 a-7 c, the buffer pressurizing cavity can have a plurality of pore medium filling structure forms for effectively reducing the flow rate of the fluid and achieving the effect of fluid pressurization, wherein fig. 7a shows that the filling medium is spherical particles, fig. 7b shows a silk-screen multi-gap laminate filling structure, and fig. 7c shows an irregular particle multi-gap filling structure.

When the self-priming composite shield pump is in a self-priming exhaust stage, the pump and the direct-current permanent magnet motor are sealed in a composite shield pump cavity filled with pumped media, and pre-filled fluid is stored in the ejector, the centrifugal end, the flow guide cavity, the buffer pressurization cavity and the gas-liquid separation chamber. The embodiment adopts the direct current permanent magnet motor with higher safety and efficiency, and compared with the traditional asynchronous motor, although the direct current permanent magnet motor drives the fluid to obtain the working fluid with higher speed, the gas-liquid separation of the composite canned motor pump is more difficult, the high-speed impeller is easily attached, and the self-absorption function of the composite canned motor pump cannot be realized.

Therefore, as shown in fig. 10, in order to avoid the problem of gas-liquid separation caused by the high rotation speed of the dc permanent magnet motor, after the fluid mixed by the ejector is driven at a high speed by the centrifugal impeller, the fluid is firstly guided out by the centrifugal pumping chamber, guided by the guide cavity, and then enters the buffer pressurizing cavity for buffer pressurizing, so that the bubbles in the pump at the self-priming stage can obtain longer free floating time to complete gas-liquid separation. The buffer pressurizing cavity with the multi-pore double-layer plate series structure is provided with a certain arrangement of buffer fins, high-speed fluid is guided by the buffer fins of the primary buffer cavity, the speed of the high-speed fluid is rapidly reduced, the high-speed fluid is discharged from an outlet of the primary buffer cavity, the high-speed fluid flows into the secondary buffer cavity, the fluid medium is further decelerated, and the fluid medium is discharged from an outlet of the secondary buffer cavity. Then enters a gas-liquid separation chamber or enters a next-stage buffer pressurizing cavity. Therefore, the kinetic energy obtained by driving the fluid from the high-speed centrifugal impeller can be effectively converted into potential energy in a multi-stage buffering mode, the speed reduction and pressurization of the working medium are completed, the hydraulic loss is reduced, and meanwhile, the gas-liquid separation requirement is met.

The fluid flowing out of the outlet of the buffer pressurizing cavity directly enters the gas-liquid separation chamber, the speed of a fluid medium in the gas-liquid separation chamber is obviously reduced due to the functions of flow guiding and the buffer pressurizing cavity, the working fluid is fully retained in the gas-liquid separation chamber, and the gas-liquid separation of the compound pump is realized. If no buffer cavity is arranged, the high-speed fluid after the centrifugal impeller is driven by the direct-current permanent magnet motor cannot be sufficiently decelerated, so that gas-liquid separation cannot be completed, the air-bound phenomenon of the impeller is dominant, and self-priming failure can be directly caused. Meanwhile, for example, in order to keep the compact structure and the better buffering effect of the composite canned motor pump, the secondary buffer cavity and the primary buffer cavity of the buffering pressurization cavity can be kept concentric, and the outlets of the secondary buffer cavity are distributed (uniformly or non-uniformly) along the circumferential direction, the radial direction or a certain area of the cover plate of the secondary buffer cavity. In addition, the buffer pressurizing cavities and the centrifugal end can be concentrically distributed (shown in figure 16), and the compactness of the whole structure can be effectively improved.

When the self-priming composite shield pump is in an actual working stage, as shown in the flow schematic diagrams of the working stage of the composite shield pump in fig. 11 and 17, fluid to be pumped in a pump inlet pipeline is sucked into the ejector along the inlet of the composite pump, and high-speed working fluid ejected from a nozzle enters a centrifugal end after accelerated mixing through the throat of the ejector and decelerated pressurization through a diffusion section; then, the part of the fluid obtains higher speed and pressure after accelerated pressurization of the centrifugal impeller, is discharged from the centrifugal water pressurizing chamber, enters the buffer pressurizing cavity for decelerated pressurization, and is discharged from an outlet of the buffer pressurizing cavity, so that deceleration and pressurization of the working medium are realized. The fluid flowing out of the buffer pressurizing cavity outlet enters the gas-liquid separation chamber, one part of the fluid is discharged through the outlet of the composite pump, the other part of the fluid which is not discharged out of the pump body continuously and circularly flows in the gas-liquid separation chamber to provide working fluid for the ejector nozzle, and the strong negative pressure formed near the nozzle outlet continuously sucks the fluid to be pumped at the pump inlet, so that the process is repeated, and the normal pumping of the fluid to be pumped by the composite shielding pump is realized. In the process, the buffer pressurizing cavity can effectively reduce flow resistance and reduce pressure loss, and simultaneously realize buffer pressurizing of the fluid at the outlet of the centrifugal end.

As shown in fig. 12 and 14, a check valve 16 or an elastic baffle 17 may be disposed at the inlet of the injector nozzle, when the self-priming operation phase begins, only the pre-filled fluid circulates in the pump, there is no continuous supplement of the fluid to be pumped, the pressure difference between two sides (inside the injector and the gas-liquid separation chamber) of the check valve or the elastic baffle is small, the check valve or the elastic baffle is in an open state under the action of the spring force, the elastic force of the elastic baffle or the electromagnetic force, and the liquid inside the gas-liquid separation chamber flows into the throat of the injector through the injector nozzle, where the gas-liquid mixing process is completed. Along with the deepening of the self-priming stage, the pre-filled fluid in the pump continuously acts in the processes of accelerating and pressurizing through the ejector, driving to do work through the centrifugal impeller, decelerating and pressurizing through the buffer structure and the like, the pressure difference between two sides of the check valve or the elastic retaining sheet structure is continuously increased until the self-priming stage is finished, and the check valve or the elastic retaining sheet structure overcomes the action of the elastic force or the electromagnetic force of the spring under the action of larger pressure difference and enters a closed state. As shown in fig. 13 and 15, the check valve or the elastic flap is in the closed state, and at this time, the liquid in the gas-liquid separation chamber cannot enter the injector through the nozzle position any more, and the internal circulation of the fluid in the pump stops. In the self-priming stage, the high-speed fluid flowing in from the nozzle and the strong negative pressure caused by the diffusion section form an effective entrainment effect on the gas in the guide pipe, and the fluid is decelerated and pressurized under the action of the buffer structure to complete the gas-liquid separation and realize the self-priming function of the composite shield pump; during the working stage, the liquid in the gas-liquid separation chamber does not flow back to the position of the nozzle any more, and the liquid which completes the work is directly discharged through the outlet of the composite shielding pump. The self-priming function is realized by opening or closing the working fluid at the inlet of the nozzle, and the internal circulation of the actual working stage is stopped, so that the hydraulic efficiency of the pump is improved powerfully.

As shown in fig. 18, the self-priming compound canned motor pump of the present invention can also form a pump stack 20 in a parallel configuration with a single centrifugal pump. The self-suction composite shield pump 203 and the centrifugal pump 206 share a pump set inlet 201 and a pump set outlet 202, namely the pump set inlet 201 is respectively communicated with a self-suction composite shield pump inlet 204 and a centrifugal pump inlet 207; the self-suction composite shield pump outlet 205 and the centrifugal pump outlet 208 are respectively communicated with the pump group outlet 202. The pump set does not influence the exhaust in the self-suction exhaust stage, improves the performance of the pump in the non-self-suction normal working stage and meets different application requirements.

In conclusion, the invention keeps the characteristics of compact integral structure and high integral degree of the canned motor pump, and simultaneously realizes gas-liquid separation and self-absorption of the canned motor pump under the high-rotating-speed working condition and improves the hydraulic characteristic of the canned motor pump by driving the centrifugal impeller by the direct-current permanent magnet motor and matching the buffer pressurizing cavity and the ejector on the premise of not increasing the running noise of the canned motor pump, the maximum absorption distance can reach more than 9m, and the technical problem of gas-liquid separation in a high-rotating-speed small pump cavity is solved.

While the invention has been described in connection with specific embodiments thereof, it will be understood that these should not be construed as limiting the scope of the invention, which is defined in the following claims, and any variations which fall within the scope of the claims are intended to be embraced thereby.

Claims

1. Self-priming composite shield pump based on direct current permanent magnet motor, including pump inlet, sprayer, centrifugation end, buffering pressure boost chamber, gas-liquid separation room and pump export, its characterized in that: the inlet of the pump is connected with the inlet of the ejector, the diffusion section of the ejector is connected with the inlet of the centrifugal end, the outlet of the centrifugal end is communicated with the inlet of the buffer pressurizing cavity, the outlet of the buffer pressurizing cavity is communicated with the gas-liquid separation chamber, and the gas-liquid separation chamber is communicated with the outlet of the pump;

the buffer pressurizing cavity is used for rapidly decelerating and pressurizing the high-speed pressurized fluid at the outlet of the centrifugal end; in the exhaust self-priming stage, the flow velocity of gas-liquid mixed fluid is reduced, and meanwhile, the bubble breakage is reduced; in the non-exhaust stage, the flow pressure loss is reduced, and simultaneously the buffering pressurization of the fluid at the outlet of the centrifugal end is realized;

the ejector is communicated with the gas-liquid separation chamber through a nozzle.

2. The self-priming composite shield pump based on the direct-current permanent magnet motor is characterized in that: the outlets of the buffer pressurizing cavities are distributed along the circumferential direction or the radial direction in a plane, or pores are arranged in space.

3. The self-priming composite shield pump based on the direct-current permanent magnet motor as claimed in claim 1 or 2, wherein: the buffer pressurizing cavity is a structure formed by connecting porous laminated plates in series, a porous space structure, a porous medium filling structure, a single roundabout flow channel combination structure or a structure formed by combining a plurality of roundabout flow channels.

4. The self-priming composite shield pump based on the direct-current permanent magnet motor is characterized in that: the multi-hole laminate series structure is characterized in that a fixed guide vane or a rotary guide vane is additionally arranged in the buffering pressurization cavity, or an inlet and an outlet of the buffering pressurization cavity are arranged into a rotatable guide vane.

5. The self-priming composite shield pump based on the direct-current permanent magnet motor is characterized in that: the buffer pressurizing cavity and the centrifugal impeller are distributed up and down or concentrically; when the centrifugal pump is vertically distributed, the outlet of the centrifugal end is communicated with the buffer pressurizing cavity through the flow guide cavity.

6. The self-priming composite shield pump based on the direct-current permanent magnet motor is characterized in that: and after the self-priming stage of the composite shield pump is finished, the check valve is closed under the driving of the internal and external differential pressure of the ejector, liquid in the gas-liquid separation chamber cannot enter the ejector through the nozzle, and the internal circulation flow of the pump is stopped.

7. The self-priming composite shield pump based on the direct-current permanent magnet motor is characterized in that: at least one buffer pressurizing cavity, at least one centrifugal end and at least one centrifugal end outlet.

8. A combined self priming compound canned motor pump comprising at least one self priming compound canned motor pump as claimed in any one of claims 1 to 7 and at least one centrifugal pump, characterised in that: the inlet of the self-suction type composite shield pump is connected with the inlet of the centrifugal pump in parallel, and the outlet of the self-suction type composite shield pump is connected with the outlet of the centrifugal pump in parallel.