CN112392773A

CN112392773A - Low-noise shielding pump with axial force balance tube structure

Info

Publication number: CN112392773A
Application number: CN202011112280.7A
Authority: CN
Inventors: 徐亮
Original assignee: Individual
Current assignee: Suzhou Qigujia Technology Co ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2021-02-23
Anticipated expiration: 2039-12-13
Also published as: CN110925244A; CN110925244B; CN112392773B; CN112392774B; CN112392774A

Abstract

The invention discloses a low-noise shielding pump with an axial force balance pipe structure, which comprises a rotor component, a circulating pipe, a balance pipe and a partition plate, wherein the rotor component sequentially penetrates through a pump body, a pump cover and a motor casing and is rotatably supported through a bearing, the pump body, the pump cover and the motor casing are fixed through fasteners, and the tail wall surface of the motor casing and the side wall of the outlet end of the pump body are provided with through holes and connected through the circulating pipe. The rotor component comprises a main shaft, an impeller and a balance assembly, the main shaft is supported and installed on a central axis of the pump body, the pump cover and the motor shell through a bearing, the impeller is installed on the main shaft and located in the pump body, the balance assembly is installed on the main shaft and located in the motor shell, a static partition plate is installed in the motor shell, the partition plate and the balance assembly are overlapped in the axial direction of the main shaft and divide the interior of the motor shell into two regions, one region is connected to the outlet end of the pump body through a circulating pipe, and the other region is connected to the inlet end of the pump body through.

Description

Low-noise shielding pump with axial force balance tube structure

Technical Field

The invention relates to the field of canned motor pumps, in particular to a low-noise canned motor pump with an axial force balance tube structure.

Background

The shield pump is one of centrifugal pumps and is often used for conveying high-risk toxic and harmful media, because the media need a conveying device to be completely leak-free, and the conventional centrifugal pump needs to be connected with a main shaft through a coupling and other parts due to the external arrangement of a motor, a dynamic seal must exist, and even the dynamic seal is a high-level mechanical seal, the complete leak-free cannot be realized. The motor of the canned motor pump is internally arranged, so that no dynamic seal exists, and the rest static seals can realize zero leakage under the condition of not being under the ultrahigh voltage, thereby realizing no leakage of the canned motor pump.

The canned motor pump needs to guide liquid into the motor, and the bearings are usually graphite sliding bearings, and due to the axial force of the rotating parts, the abrasion of the sliding bearings is the most common fault.

Among the prior art, axial force is usually balanced through seting up the balancing hole on the impeller, and seting up of balancing hole leads to the leakage in high-low pressure district great, influences pump efficiency, and balanced imperfect moreover, when rotating member received axial disturbance, also do not have corresponding structure to balance and reset, leans on bearing department to carry out hard resistance completely, further reduces slide bearing's life-span.

Disclosure of Invention

The invention aims to provide a low-noise shielding pump with an axial force balance pipe structure so as to solve the problems in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides a low noise canned motor pump with axial force balanced tube structure, includes the rotor part, the pump body, the pump cover, motor casing, bearing, the rotor part passes the pump body in proper order, the pump cover, the motor casing carries out the rotation support through the bearing, and the pump body, the pump cover, the motor casing is fixed through the fastener each other, canned motor pump still includes the circulating pipe, offers the through-hole on motor casing afterbody wall and the pump body exit end lateral wall and uses the circulating pipe to connect.

The rotor part comprises an impeller, the impeller rotates in the pump body to do work, the working principle is the same as that of a common centrifugal pump, the shield pump is compared with the common centrifugal pump, the outlet end of the impeller is communicated with the inside of a motor, a pump cover and a motor shell are sequentially connected and mutually fastened to form a main static part of the shield pump to form a complete whole, a bearing supports the rotor part, part of high-pressure liquid at the outlet of the pump body flows back into the motor shell through arranging a circulating pipe, the high-pressure liquid flows back to the back of the impeller and then flows to the outlet of the pump body together with the liquid at the outlet of the impeller, the circulating flow is related to the outlet pressure of the pump body, the back pressure of the impeller and the flow resistance on a circulating passage, but the flow always exists, the circularly flowing medium can fully take away the heat generated by the working of a stator and a rotor in the motor shell, therefore, the conveying temperature needs to be strictly controlled, compared with the traditional heat dissipation measures that a heat dissipation fin is arranged on the outer surface of a motor shell and the like, the medium flowing through the circulating pipe can fully cool the motor, and the medium flowing from the back of the impeller is prevented from accumulating in the motor to form a flowing dead zone, so that potential safety hazards are caused by heat accumulation.

Further, the canned motor pump still includes the balance pipe, the partition dish, the rotor part includes the main shaft, impeller and balanced subassembly, the main shaft passes through the bearing support to be installed at the pump body, the pump cover, on the axis of motor casing, the impeller is installed on the main shaft and is located the pump body, balanced subassembly is installed on the main shaft and is located the motor casing, install static partition dish in the motor casing, partition dish and balanced subassembly coincide and divide into two regions with the motor casing in the main shaft axial, one of them region is connected to pump body exit end through the circulating pipe, another region is connected to pump body entrance point through the balance pipe.

The invention discloses a shield pump, which is characterized in that the bearing abrasion of a shield pump is a ubiquitous problem, the axial force on a rotor part is a main factor causing abrasion, a balance assembly is arranged, and the axial force balance of the rotor part is realized by matching a balance pipe and a partition disc, and the specific principle is as follows: balance assembly one side is for connecting the impeller back, the high-pressure region of pump body exit end, one side is the low-pressure region of connecting the canned motor pump entrance point, the high-pressure region is the impeller with the pressure differential dorsad that the low-pressure region produced on balance assembly, and its axial force of pressure differential because the backplate is around at the impeller department points to the impeller, these two kinds of power offset each other, accomplish the balanced process of axial force, the bay dish is the static piece of installing in the motor casing, corresponding with balance assembly, because a static is moved, there is corresponding clearance to prevent wearing and tearing to take place, because balance assembly is the axial force that the differential pressure of backplate produced around will balancing impeller department, from canned motor pump import drainage can make things convenient for balance assembly's size to calculate, the main relation is: the pressure differential effective area of the balance assembly is approximately equal to the impeller inlet area minus the impeller hub area. The high pressure area and the low pressure area reach the pressure drop of the balancing component from the drainage position of the high pressure area and the low pressure area respectively, and the pressure drop acting area of the balancing component needs to be slightly adjusted correspondingly.

Further, the balance assembly comprises a gap adjusting block and a gap adjusting disc, the gap adjusting block and the gap adjusting disc are respectively sleeved on the main shaft and are axially abutted, the gap adjusting block is closer to the impeller than the gap adjusting disc, the gap adjusting block and the partition disc are provided with conical opposite inclined surfaces, the large-diameter end of the conical inclined surface faces the impeller, and a gap is reserved between the gap adjusting block and the partition disc; the clearance adjusting disc and the partition disc have a radial clearance along the axis of the main shaft.

The clearance adjusting block and the partition plate face to each other to reserve a clearance, the clearance adjusting plate and the partition plate face to each other to reserve a clearance, a third pressure area (middle area) is reserved between the two clearances, a middle area is arranged to achieve the micro self-adaptive adjustment of axial force, and when the rotor component is subjected to the axial force and axially moves for a certain distance, the rotor component is away from the pump body and moves as an example: the inclined plane clearance between the clearance adjusting block and the partition disc is reduced, the vertical plane clearance between the clearance adjusting disc and the partition disc is increased, so that the pressure intensity of the middle area is increased, the pressure of the middle area on the clearance adjusting disc is reduced, the driving force for the clearance adjusting disc to move rightwards is reduced, when the inclined plane clearance between the clearance adjusting block and the partition disc is reduced to be very small, the pressure intensity of the middle area is approximately equal to the pressure intensity of the low-pressure area, the balance assembly does not provide rightwards balance force any more, and the rotor component has leftwards axial force due to the differential pressure of the front back plate and the rear back plate at the impeller, so that the rotor component is; when the rotor components are disturbed to play to the left: the clearance between the clearance adjusting disc and the partition disc is reduced, the clearance between the clearance adjusting block and the partition disc is increased, so that the pressure intensity of the middle area is increased, the increased pressure intensity of the middle area provides larger right pressure for the clearance adjusting disc, and the leftward movement trend is resisted until the rotor component eliminates disturbance and resets.

Furthermore, the surface of the gap part of the gap adjusting disc, which is adjacent to the partition disc, is a pressure relief surface, a liquid blowing groove is arranged on the pressure relief surface, and the liquid blowing direction of the liquid blowing groove is that the liquid is blown from the two sides of the pressure relief surface to the middle part of the pressure relief surface. The impeller is subjected to axial force generated by pressure difference to the left, so if the balance assembly loses the balance function due to unreasonable gap arrangement or other factors, the rotor assembly has a leftward movement trend, and in order to prevent the pressure relief surface from colliding with the partition plate, the pressure relief surface is provided with a liquid blowing groove.

Furthermore, the liquid blowing groove is arc-shaped, one end of the liquid blowing groove is connected with the outer edge of the pressure release surface, the other end of the liquid blowing groove is connected with the middle part of the pressure release surface, the end part of the liquid blowing groove at the edge of the pressure release surface is tangential, and the end part of the liquid blowing groove at the middle part of the pressure release surface is radial. The liquid blowing groove pressurizes and fills liquid in a gap between the gap adjusting disc and the partition disc, so if the liquid in the middle area is pressurized and filled into the gap, the flow of the middle area to the low-pressure area is increased, the low-pressure area is communicated with the inlet of the shield pump, the whole flow loss of the shield pump is increased when the leakage flow at the balance component is large, and the efficiency of the whole machine is reduced; the liquid blowing groove is used for blowing liquid at the outer edge into the gap, namely, liquid in a low-pressure area is pressurized and filled in the gap, and the liquid in the gap is close to the liquid pressure in a middle area, so that the leakage is small, the flow loss at the position of the balance assembly is small, and the overall efficiency is not influenced.

Furthermore, the canned motor pump still includes extension section and inducer, and the extension section passes through the fastener and installs in the pump body import, and the inducer passes through the fastener and installs on the main shaft and close to the impeller entrance point.

The medium conveyed by the shield pump is often flammable, explosive and high-risk liquid as described above, and a no-dynamic-seal shield pump structure is required to be generated only when zero leakage occurs, and some media are easy to vaporize, so that the cavitation performance of the shield pump should be reliably ensured, and after the inducer is added, the cavitation performance is greatly improved, and the medium is prevented from vaporizing at the inlet of the impeller and causing potential safety hazards and harm. The extension section accommodates the inducer.

Further, the rotor part also comprises a mouth ring, the mouth ring is arranged on the outer surface of the impeller inlet, and the outer surface of the mouth ring is provided with threads.

The invention uses a dynamic mouth ring structure, a gap which is slightly smaller than the conventional gap is reserved between the mouth ring and the pump body, corresponding threads are arranged on the mouth ring for blowing, the blowing direction is towards the pump cavity of the pump body, and the specific thread direction is as follows: when the impeller rotates clockwise from the inlet end, the rotation direction of the threads is left-handed, the threads rotate along with the impeller, surrounding liquid is pushed in the thread tooth grooves to flow towards the pump cavity, leakage from the pump cavity to the inlet of the pump body is resisted, flow loss of the canned motor pump is reduced, and overall efficiency is improved.

Further, the thread is a fine-pitch rectangular thread. The fine thread has a shorter pitch, the rectangular tooth socket is larger, and the liquid pushing performance is better.

Furthermore, the rotor part also comprises a bearing sleeve, the bearing is a sliding bearing, the bearing sleeve is sleeved on the main shaft and is in transmission connection with the main shaft, and the outer surface of the bearing sleeve is abutted against the bearing. Because of the particularity of the flow field in the canned motor pump, the supporting bearing of the rotor part is usually a sliding bearing made of graphite to prevent the main shaft from being abraded, the sliding bearing made of metal is used, the bearing sleeve is used for supporting surface contact, the bearing sleeve is made of softer materials such as graphite, and after abrasion occurs, the bearing sleeve is more convenient to replace, and the cost is reduced.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, the interior of the motor shell is communicated with the outlet of the pump body, so that media flowing into the motor form circulation, a flow dead zone is eliminated, and heat accumulation in the motor is prevented; the low pressure at the inlet of the impeller is guided into the motor shell and is separated from the partition disc into two areas through the balancing assembly, the two areas respectively generate axial force deviating from the inlet of the impeller on the balancing assembly to balance the axial force applied to the impeller and facing the inlet of the impeller, when the rotor component axially moves, the related clearance between the balancing assembly and the partition disc is adaptively changed to generate resetting force, and the axial movement of the rotor component is prevented from being kept for a long time; when a liquid blowing groove on the pressure relief surface runs, surrounding liquid is blown into a gap between the gap adjusting disc and the partition disc, so that the gap adjusting disc and the partition disc are prevented from being impacted; the moving port ring with the threads reduces flow loss at the impeller and improves the efficiency of the whole machine.

Drawings

In order that the present invention may be more readily and clearly understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings.

FIG. 1 is a schematic view of the final assembly of the present invention;

FIG. 2 is a partial view A of FIG. 1;

FIG. 3 is view C-C of FIG. 2;

fig. 4 is a partial view B of fig. 1.

In the figure: 1-rotor part, 11-spindle, 12-impeller, 13-bearing sleeve, 14-port ring, 141-thread, 15-balance assembly, 151-clearance adjusting block, 152-clearance adjusting disc, 1521-pressure relief surface, 1522-liquid blowing groove, 16-inducer, 2-pump body, 3-pump cover, 4-motor shell, 5-rear cover, 6-lengthening section, 71-circulating pipe, 72-balance pipe, 8-partition disc and 9-sliding bearing.

Detailed Description

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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.

As shown in fig. 1, a low noise canned motor pump with an axial force balance tube structure, including rotor part 1, the pump body 2, the pump cover 3, the motor casing 4, bearing 9, rotor part 1 passes the pump body 2 in proper order, pump cover 3, motor casing 4 and carries out the rotation support through bearing 9, the pump body 2, pump cover 3, motor casing 4 are fixed through the fastener each other, canned motor pump still includes circulating pipe 71, set up the through-hole on motor casing 4 afterbody wall and the pump body 2 exit end lateral wall and use circulating pipe 71 to connect together.

The rotor component 1 comprises an impeller 12, the impeller 12 rotates in the pump body 2 to do work, the working principle is the same as that of a common centrifugal pump, compared with the common centrifugal pump, the shield pump is characterized in that the outlet end of the impeller 12 is communicated with the inside of a motor, a pump cover 3 and a motor shell 4 are sequentially connected and mutually fastened to form a main static component of the shield pump to form a complete whole, a bearing 9 supports the rotor component 1, part of high-pressure liquid at the outlet of the pump body 2 flows back into the motor shell 4 through arranging a circulating pipe 71, the high-pressure liquid flows back to the back of the impeller 12 and then flows to the outlet of the pump body 2 together with the liquid at the outlet of the impeller 12, the circulating flow is related to the outlet pressure of the pump body 2, the back pressure of the impeller 12 and the flow resistance on a circulating path, but the flow always exists, and the heat generated by the working of a, compared with the traditional heat dissipation measures that a cooling fin is arranged on the outer surface of the motor shell 4 and the like, the medium flowing through the circulating pipe 71 can fully cool the motor, and the medium flowing from the back of the impeller 12 is prevented from accumulating in the motor to form a flowing dead zone, so that the heat accumulation causes potential safety hazards.

As shown in fig. 1 and 2, the canned motor pump further includes a balance pipe 72 and a partition disk 8, the rotor component 1 includes a main shaft 11, an impeller 12 and a balance assembly 15, the main shaft 11 is supported and mounted on a central axis of the pump body 2, the pump cover 3 and the motor housing 4 through a bearing 9, the impeller 12 is mounted on the main shaft 11 and is located in the pump body 2, the balance assembly 15 is mounted on the main shaft 11 and is located in the motor housing 4, the stationary partition disk 8 is mounted in the motor housing 4, the partition disk 8 and the balance assembly 15 are overlapped in an axial direction of the main shaft 11 and divide the interior of the motor housing 4 into two regions, one region is connected to an outlet end of the pump body 2 through a circulation pipe 71, and the other region is connected to an inlet end.

The invention provides a balance assembly 15, which is matched with a balance pipe 72 and a partition disc 8 to realize the axial force balance of the rotor part 1, and the specific principle is as follows: the balancing assembly 15 has one side of a high pressure area P1 connected with the back of the impeller 12 and the outlet end of the pump body 2, and one side of a low pressure area P3 connected with the inlet end of the canned motor pump, the high pressure area P1 and the low pressure area P3 generate a pressure difference on the balancing assembly 15 to back to the impeller 12, and the impeller 12 is directed to the impeller 12 by the axial force thereof due to the pressure difference between the front and rear back plates, the two forces are mutually offset to complete the balancing process of the axial force, the partition plate 8 is a static part installed in the motor housing 4 and corresponds to the balancing assembly 15, and because of static and dynamic, a corresponding gap exists to prevent abrasion, because the balancing assembly 15 is to balance the axial force generated by the differential pressure between the front and rear back plates at the impeller 12, the size calculation of the balancing assembly 15 can be facilitated by draining from the inlet: the pressure differential effective area of the balancing assembly 15 is approximately equal to the impeller inlet area minus the impeller 12 hub area. The pressure drop from the flow-off point of high pressure zone P1 and low pressure zone P3 to balancing assembly 15 requires a corresponding slight adjustment of the pressure differential acting area of balancing assembly 15.

As shown in fig. 2, the balance assembly 15 includes a gap adjusting block 151 and a gap adjusting disc 152, the gap adjusting block 151 and the gap adjusting disc 152 are respectively sleeved on the main shaft 11 and axially abutted, the gap adjusting block 151 is closer to the impeller 12 than the gap adjusting disc 152, the gap adjusting block 151 and the partition disc 8 have conical opposite inclined surfaces, a large-diameter end of the conical inclined surface faces the impeller 12, and a gap exists between the gap adjusting block 151 and the partition disc 8; the gap adjusting disk 152 has a gap with the partition disk 8 in the radial direction of the axis of the main shaft 11.

The gap adjusting block 151 and the partition disc 8 face each other to reserve a gap, the gap adjusting disc 152 and the partition disc 8 face each other to reserve a gap, a third pressure area P2 (middle area) is reserved between the two gaps, pressure distribution is sequentially from high to low, P1> P2> P3, a middle area P2 is arranged to achieve tiny adaptive adjustment of axial force, when the rotor component 1 is subjected to the axial force and axially moves for a certain distance, taking the rightward movement in fig. 2 as an example: the bevel clearance between the gap adjusting block 151 and the partition plate 8 is reduced, the vertical surface clearance between the gap adjusting plate 152 and the partition plate 8 is increased, so that the pressure of P2 is close to P3 and far away from P1, the pressure of the middle area P2 on the gap adjusting plate 152 is reduced, so that the driving force of the rightward movement of the gap adjusting plate 152 is reduced, when the bevel clearance between the gap adjusting block 151 and the partition plate 8 is reduced to be very small, the pressure of the middle area P2 is approximately equal to the pressure of P3, so that the balance assembly 15 does not provide rightward balance force any more, and the front and rear back plate differential pressure at the impeller 12 enables the rotor component 1 to have leftward axial force, so that the rotor component 1 is reset; when the rotor part 1 is disturbed to play to the left: the clearance between the timing disc 152 and the divider disc 8 decreases and the clearance between the timing block 151 and the divider disc 8 increases so that the P2 region is in greater communication with P1 and the pressure increases, the increased pressure in the P2 region providing greater rightward pressure to the timing disc 152, resisting the tendency to move leftward until the rotor member 1 is upset and reset.

As shown in fig. 2 and 3, a pressure relief surface 1521 is formed on a surface of the gap adjusting disc 152 adjacent to the partition disc 8, a liquid blowing groove 1522 is formed in the pressure relief surface 1521, and the liquid blowing direction of the liquid blowing groove 1522 is from two radial sides of the pressure relief surface 1521 to the middle of the pressure relief surface 1521. The axial force generated by the impeller 12 due to the pressure difference is leftward, so if the balance assembly 15 loses the balance function due to unreasonable gap arrangement or other factors, the rotor assembly 1 has a leftward play tendency, in order to prevent the pressure relief surface 1521 from hitting the partition plate 8, the pressure relief surface 1521 is provided with a liquid blowing groove 1522, when the gap adjusting plate 152 is very close to the partition plate 8, the liquid blowing groove 1522 blows the liquid in the connecting area of one end thereof to the gap to prevent the gap from being further closed, thereby preventing the gap adjusting plate 152 from hitting the partition plate 8.

As shown in fig. 3, the liquid drum groove 1522 is arc-shaped, one end of the liquid drum groove 1522 is connected with the outer edge of the pressure relief surface 1521, the other end is connected with the middle part of the pressure relief surface 1521, the end of the liquid drum groove 1522 at the outer edge of the pressure relief surface 1521 is tangential, and the end of the liquid drum groove 1522 at the middle part of the pressure relief surface 1521 is radial. The liquid blowing groove 1522 pressurizes and fills the liquid in the gap between the gap adjusting disc 152 and the partition disc 8, so if the liquid in the P2 area is pressurized and filled into the gap, the flow rate of the P2 to the P3 area is increased, and the P3 area leads to the inlet of the shield pump, so that the leakage flow rate at the balance assembly 15 is large, the flow loss of the whole shield pump is increased, and the overall efficiency of the whole shield pump is reduced; the liquid blowing groove 1522 is used for blowing liquid at the outer edge into the gap, namely, liquid in the P3 area is pressurized to fill the gap, the pressure of the liquid in the gap is close to that of the liquid in the P2 area, so that leakage is small, flow loss at the balance component 15 is small, and the overall efficiency is not affected.

As shown in fig. 1, the canned motor pump further includes an elongated section 6 and an inducer 16, the elongated section 6 is mounted to the inlet of the pump body 2 by fasteners, and the inducer 16 is mounted to the main shaft 11 by fasteners and is close to the inlet end of the impeller 12.

The medium conveyed by the shield pump is often flammable, explosive and high-risk liquid as described above, and a no-dynamic-seal shield pump structure is required to be generated only when zero leakage occurs, and some of the mediums are easy to vaporize, so that the cavitation performance of the shield pump should be reliably ensured, and after the inducer 16 is added, the cavitation performance is greatly improved, and the medium is prevented from vaporizing at the inlet of the impeller 12 and causing potential safety hazards and harm. The elongated section 6 houses an inducer 16.

As shown in fig. 1 and 4, the rotor component 1 further comprises a mouth ring 14, the mouth ring 14 is mounted on the outer surface of the inlet of the impeller 12, and the outer surface of the mouth ring 14 is provided with threads 141.

The mouth ring 14 is an anti-abrasion part commonly used at the impeller inlet of a centrifugal pump, and is divided into a movable mouth ring fixed on the impeller 12 and a static mouth ring fixed with a pump body according to different arrangement positions, the invention uses the movable mouth ring structure, a gap which is 20-30% smaller than the conventional gap is reserved between the mouth ring 14 and the pump body 2, corresponding threads are arranged on the mouth ring 14 for blowing, the blowing direction is towards the pump cavity of the pump body 2, and the specific thread direction is as follows: when the impeller 12 rotates clockwise from the inlet end, the rotation direction of the screw thread 141 is left-handed, the screw thread 141 rotates along with the impeller 12, surrounding liquid is pushed in the screw thread tooth socket to flow towards the pump cavity, leakage from the pump cavity to the inlet of the pump body is resisted, flow loss of the canned motor pump is reduced, and overall efficiency is improved.

The thread 141 is a fine rectangular thread. The fine thread has a shorter pitch, the rectangular tooth socket is larger, and the liquid pushing performance is better.

As shown in fig. 1, the rotor component 1 further includes a bearing sleeve 13, the bearing 9 is a sliding bearing, the bearing sleeve 13 is sleeved on the main shaft 11 and is in transmission connection with the main shaft 11, and the outer surface of the bearing sleeve 13 abuts against the bearing 9. Because of the particularity of the flow field in the canned motor pump, the supporting bearing of the rotor part 1 is usually a sliding bearing made of graphite to prevent the main shaft from being abraded, the sliding bearing made of metal is used, the bearing sleeve 13 is used for supporting surface contact, the bearing sleeve 13 is made of softer materials such as graphite, and after abrasion occurs, the bearing sleeve 13 is more convenient to replace, and the cost is reduced.

The operation process of the invention is as follows: the shield pump sucks a medium from an inlet, the medium enters the impeller 12 and leaves the shield pump from an outlet of the pump body 2, pressure liquid at a back plate of the impeller 12 flows into the motor for cooling, and a flow circulation is formed through a circulation pipe 71 arranged on the side surface of the motor shell 4, so that a flow dead zone is prevented; the axial force of the rotor component 1 is mainly divided into two parts, one part is the axial force towards the inlet of the impeller 12 caused by the area difference of the front cover plate and the rear cover plate at the impeller, the other part is the axial force which is generated on the balancing component 15 by the area separated by the partition plate 8 and the balancing component 15 in the motor shell 4 and deviates from the impeller 12, the two parts are offset, if the rotor component 1 is disturbed and generates axial movement, the balancing component 15 can change the force application size of the two side areas on the balancing component 15 according to the difference of the movement direction, and therefore dynamic balance of the axial force is achieved.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The utility model provides a low noise canned motor pump with axial force balanced tube structure, includes rotor part (1), the pump body (2), pump cover (3), motor casing (4), bearing (9), rotor part (1) passes the pump body (2), pump cover (3), motor casing (4) in proper order and carries out the rotation support through bearing (9), the pump body (2), pump cover (3), motor casing (4) are fixed through the fastener each other, its characterized in that: the canned motor pump further comprises a circulating pipe (71), and through holes are formed in the wall surface of the tail part of the motor shell (4) and the side wall of the outlet end of the pump body (2) and are connected through the circulating pipe (71);

the canned pump further comprising a balance tube (72), a partition disc (8), the rotor component (1) comprising a main shaft (11), an impeller (12) and a balance assembly (15), the main shaft (11) is supported and arranged on the central axis of the pump body (2), the pump cover (3) and the motor shell (4) through a bearing (9), the impeller (12) is arranged on the main shaft (11) and is positioned in the pump body (2), the balance component (15) is arranged on the main shaft (11) and is positioned in the motor shell (4), a static partition plate (8) is arranged in the motor shell (4), the partition plate (8) and the balance component (15) are overlapped in the axial direction of the main shaft (11) and divide the interior of the motor shell (4) into two areas, one of the zones is connected to the outlet end of the pump body (2) by a recirculation pipe (71), the other zone is connected to the inlet end of the pump body (2) by a balancing pipe (72);

the balance assembly (15) comprises a gap adjusting block (151) and a gap adjusting disc (152), the gap adjusting block (151) and the gap adjusting disc (152) are respectively sleeved on the main shaft (11) and are axially abutted, the gap adjusting block (151) is closer to the impeller (12) than the gap adjusting disc (152), the gap adjusting block (151) and the partition disc (8) are provided with conical opposite inclined planes, the large-diameter end of the conical inclined plane faces the impeller (12), and a gap is reserved between the gap adjusting block (151) and the opposite inclined planes of the partition disc (8); the clearance adjusting disc (152) and the partition disc (8) have a clearance along the radial direction of the axis of the main shaft (11);

the surface of the gap position, adjacent to the partition disc (8), on the gap adjusting disc (152) is a pressure relief surface (1521), a liquid blowing groove (1522) is arranged on the pressure relief surface (1521), and the liquid blowing direction of the liquid blowing groove (1522) is that the liquid is blown from the two radial sides of the pressure relief surface (1521) to the middle part of the pressure relief surface (1521);

the rotor component (1) further comprises a mouth ring (14), the mouth ring (14) is installed on the outer surface of the inlet of the impeller (12), and the outer surface of the mouth ring (14) is provided with threads (141).

2. The canned motor pump with an axial force balance tube structure of claim 1, wherein: the drum liquid groove (1522) are arc-shaped, one end of the drum liquid groove (1522) is connected with the outer edge of the pressure relief surface (1521), the other end of the drum liquid groove is connected with the middle part of the pressure relief surface (1521), the end part of the drum liquid groove (1522) located at the outer edge of the pressure relief surface (1521) is tangential, and the end part of the drum liquid groove (1522) located at the middle part of the pressure relief surface (1521) is radial.

3. The canned motor pump with an axial force balance tube structure of claim 1, wherein: the thread (141) is a fine-pitch rectangular thread.