CN112049793A

CN112049793A - High-efficiency low-vibration screw pump

Info

Publication number: CN112049793A
Application number: CN202011111852.XA
Authority: CN
Inventors: 胡奕; 黄文�; 常肖杨; 谢承健; 汪旭辉; 刘巍
Original assignee: Huangshan Industry Pump Making Co ltd
Current assignee: Huangshan Industry Pump Making Co ltd
Priority date: 2020-10-16
Filing date: 2020-10-16
Publication date: 2020-12-08

Abstract

The invention provides a high-efficiency low-vibration screw pump, which comprises: the main screw, the slave screw, the pump body, the rear end cover, the front end cover and the gland assembly; the rear end cover and the front end cover are respectively arranged at two axial end parts of the pump body, the main screw rod and the slave screw rod are arranged in the pump body, and the main screw rod and the slave screw rod are mutually meshed to form a high-pressure sealing cavity; the gland assembly is sleeved in the front end cover and forms a low-pressure sealing cavity with the front end cover and the main screw rod; the outer circle section of the main screw matched with the front end cover is provided with uniformly distributed annular sinking grooves, the central shaft of the main screw is provided with an axial long hole, a radial hole close to the shaft seal installation part is provided with a radial hole which penetrates through the axial long hole, and the radial hole is communicated with the low-pressure sealing cavity. The invention can solve the problems of unbalanced axial force, low volumetric efficiency, high vibration and easy damage of the main screw and the slave screw under the high-pressure working condition, and improves the service life and the reliability of the screw pump.

Description

High-efficiency low-vibration screw pump

Technical Field

The invention relates to the technical field of screw pumps, in particular to a high-efficiency low-vibration screw pump.

Background

The high-pressure screw pump is a rotary pump which transports or pressurizes a liquid by changing the volume and moving the engaging space formed by a pump body and a screw. The screw pump utilizes the screw meshing principle, depends on the mutual meshing of the rotating screws in the pump sleeve, seals the conveyed medium in the meshing cavity, continuously pushes the medium to the outlet along the axial direction of the screws at a constant speed, and when the screw pump works, the liquid enters the sealed space surrounded by the screw section and the pump shell after being sucked. When the main screw rotates, the sealed volume of the screw pump improves the pressure of the screw pump under the extrusion of the screw teeth, the screw pump drives the screw engaged with the screw pump to rotate together, the volume of the screw engaging space at one end of the suction cavity is gradually increased, and the pressure is reduced. The liquid enters the volume of the engagement space under the action of the pressure difference, and when the volume is increased to the maximum to form a sealed cavity, the liquid is in the sealed cavities to one end of the discharge cavity. At this time, the volume of the screw engagement space at one end of the discharge chamber is gradually reduced to discharge the liquid. Since the screw is rotated at a constant speed, the flow rate of the discharged liquid is also uniform. The existing high-pressure screw pump neglects the problems of large leakage quantity of medium on the joint surface of a high-pressure oil overflowing part caused under a high-pressure working condition in the structural design, unbalanced axial force, low volumetric efficiency and easy damage when a main screw and a slave screw work; the problem of high pump vibration is caused by large vibration of a rolling bearing caused by unbalance, misalignment and structural resonance of a main screw rod.

Disclosure of Invention

The invention provides a high-efficiency low-vibration screw pump, which solves the problems that a high-pressure screw pump overlooks the high-pressure working condition in the structural design, the leakage quantity of a medium on the joint surface of a high-pressure oil overflowing part is large, the axial force is unbalanced, the volumetric efficiency is not high, and the high-vibration screw pump is easy to damage when a main screw and a slave screw work, and the vibration of a rolling bearing is large due to the unbalance, the misalignment and the structural resonance of the main screw, so that the service life and the reliability of the screw pump are improved.

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

an efficient low vibration screw pump comprising: the main screw 11, the auxiliary screw 21, the pump body 3, the rear end cover 4, the front end cover 5 and the gland assembly 6;

the rear end cover 4 and the front end cover 5 are respectively arranged at two axial end parts of the pump body 3, the main screw 11 and the slave screw 21 are arranged in the pump body 3, and the main screw 11 and the slave screw 21 are meshed with each other to form a high-pressure sealing cavity;

the gland assembly 6 is sleeved in the front end cover 5 and forms a low-pressure sealing cavity 63 with the front end cover 5 and the main screw rod 11;

the excircle section of the main screw 11 matched with the front end cover 5 is provided with uniformly distributed annular sunk grooves 113, the central shaft of the main screw 11 is provided with an axial long hole 111, a radial hole 112 is arranged at the position close to the shaft seal installation position and penetrates through the axial long hole 111, and the radial hole 112 is communicated with the low-pressure sealing cavity 63;

in operation, the high-pressure oil in the high-pressure seal chamber is decompressed by the annular sink 113 of the main screw 11 and flows into the front end cover 5, further enters the low-pressure seal chamber 63 and flows back to the suction chamber 41 in the rear end cover 4 through the radial hole 112 and the axial long hole 111.

Preferably, an axial inner cavity 31 and a radial outlet cavity 32 are formed in the pump body 3, and one main screw 11 and two slave screws 21 are engaged and arranged in the axial inner cavity 31 to form a multi-stage high-pressure sealed cavity;

in operation, the high pressure seal chamber draws feed oil from the suction chamber 41 and delivers it to the radial outlet chamber 32, and out of the radial outlet chamber 32 into an outlet line.

Preferably, the method further comprises the following steps: a pressure ring 12; the main screw 11 is provided with the pressure ring 12, the material surface hardness of the pressure ring 12 is more than or equal to HRC42, the hardening depth is more than or equal to 2mm, and the roughness of the end face of the pressure ring 12 is controlled within Ra0.8.

Preferably, a main rod convex step 114 is arranged in the middle of the main screw rod 11.

Preferably, one end of the slave screw is provided with a slave rod convex step 211 and matched with the master rod convex step 114;

in operation, the residual axial force of the slave screw 21 is transmitted from the master screw 11 to the master screw 114 via the slave screw projection step 211.

Preferably, the end of the slave screw 21 is sleeved with a balance sleeve 22, and a plurality of annular grooves 213 are formed on the outer circumferential surface of the slave screw 21 matched with the balance sleeve 22.

Preferably, an oil return hole 221 and a U-shaped step groove 222 are formed in the end surface of the balance sleeve 22;

in operation, high-pressure oil is decompressed through the annular groove 213 and flows out through the U-shaped step groove 222 and the oil return hole 221.

Preferably, the front end cap includes: a lid body 51, a first O-ring 52, and a second O-ring 53;

the cover body 51 is provided with 2 oil holes 521 which axially penetrate through, and the oil holes 521 are communicated with the oil return hole 221 of the balance sleeve 22;

a first sealing groove is formed in the contact surface of the cover body 51 and the pump body 3, and the first O-ring 52 is arranged in the first sealing groove and used for preventing oil liquid leaking from the gap of the balance sleeve 22 from overflowing from the front section of the pump body 3;

the outer border of oilhole 521 is equipped with the second seal groove, second O type sealing washer 53 sets up in the second seal groove for prevent that high-pressure fluid from scurrying into oil gallery 22 department by balanced cover 22 and lid 51 fitting surface.

Preferably, the capping assembly 6 comprises: a gland 61 and an oil seal 62;

a plurality of radial step grooves 611 are symmetrically arranged on the end surface of the gland 61, which is in contact with the pump body 3;

in operation, the oil flowing out of the annular groove 113 flows into the gland 61 through the radial step groove 611, and is isolated by the oil seal 62, so as to prevent the oil from flowing out of the main screw 11 and the gland 61.

Preferably, after the balance sleeve 22 is installed in the pump body 3, the end face of the balance sleeve 22 should be 0-0.30 mm higher than the end face of the counter bore of the pump body 3;

the total fit clearance between the pressing ring 12 and the cover body 51 and the pressing cover 61 is between 0.05 mm and 0.15 mm.

The invention provides a high-efficiency low-vibration screw pump, which reduces the flow rate flowing into a low-pressure sealing cavity by additionally arranging annular decompression grooves on a main screw and a slave screw and additionally arranging sealing elements on the leakage point of a part joint surface where high-pressure oil passes, thereby reducing the pressure of the sealing cavity and solving the problem of abnormal wear of the screws caused by the actual and theoretical deviation of the residual axial force of the screws. The problems of unbalanced axial force, low volumetric efficiency, easy damage and the like of the main screw and the slave screw under a high-pressure working condition are solved; through getting rid of conventional antifriction bearing on the lead screw, utilize the protruding type step of mobile jib and the cooperation of gland to and the setting of lead screw clamping ring, the balanced optimization of cooperation screw rod axial force has solved the high problem of screw pump vibration, has promoted the life-span and the reliability of pump.

Drawings

In order to more clearly describe the specific embodiments of the present invention, the drawings to be used in the embodiments will be briefly described below.

Fig. 1 is a schematic cross-sectional view of an efficient low vibration screw pump according to the present invention.

Fig. 2 is a schematic cross-sectional view taken along the direction a of fig. 1 according to the present invention.

Fig. 3 is a schematic structural view of the main screw provided by the present invention.

Fig. 4 is a schematic structural diagram of the slave screw provided by the invention.

Fig. 5 is a schematic structural diagram of the balance sleeve provided by the invention.

Fig. 6 is a schematic structural view of the pump body provided by the present invention.

Fig. 7 is a schematic structural diagram of a front end cap provided by the present invention.

Figure 8 is a schematic structural view of a gland assembly provided by the present invention.

Detailed Description

In order to make the technical field of the invention better understand the scheme of the embodiment of the invention, the embodiment of the invention is further described in detail with reference to the drawings and the implementation mode.

The problems that the structure of the conventional high-pressure screw pump is not simple, compact and durable, and the leakage amount of a medium on the joint surface of a high-pressure oil overflowing part is large, so that the axial force is unbalanced, the volumetric efficiency is not high, and the screw pump is easy to damage when a main screw and a slave screw work are solved; the invention provides a high-efficiency low-vibration screw pump, which solves the problem of high pump vibration caused by large vibration of a rolling bearing due to unbalance, misalignment and structural resonance of a main screw. The problems of unbalanced axial force, low volumetric efficiency, easy damage and the like of the main screw and the slave screw under a high-pressure working condition are solved. Through getting rid of conventional antifriction bearing on the lead screw, utilize the protruding type step of mobile jib and the cooperation of gland to and the setting of lead screw clamping ring, the balanced optimization of cooperation screw rod axial force has solved the high problem of screw pump vibration, has promoted the life-span and the reliability of pump.

As shown in fig. 1 and 2, an efficient low vibration screw pump includes: the main screw 11, the auxiliary screw 21, the pump body 3, the rear end cover 4, the front end cover 5 and the gland assembly 6. The rear end cover 4 and the front end cover 5 are respectively arranged at two axial end portions of the pump body 3, the main screw 11 and the slave screw 21 are arranged in the pump body 3, and the main screw 11 and the slave screw 21 are meshed with each other to form a high-pressure sealing cavity. The gland assembly 6 is sleeved in the front end cover 5 and forms a low-pressure sealing cavity 63 with the front end cover 5 and the main screw rod 11. The outer circle section of the main screw 11 matched with the front end cover 5 is provided with uniformly distributed annular sunk grooves 113, the central shaft of the main screw 11 is provided with an axial long hole 111, a radial hole 112 close to the shaft seal installation part is provided to penetrate through the axial long hole 111, and the radial hole 112 is communicated with the low-pressure sealing cavity 63. In operation, the high-pressure oil in the high-pressure seal chamber is decompressed by the annular sink 113 of the main screw 11 and flows into the front end cover 5, further enters the low-pressure seal chamber 63 and flows back to the suction chamber 41 in the rear end cover 4 through the radial hole 112 and the axial long hole 111.

Specifically, the main screw 11 and the driven screw 21 in the pump body 3 are engaged with each other and adapted, a high-pressure seal cavity is formed in the pump body, the main screw 11 is driven by a driving device to suck oil into the inner cavity of the pump body from the suction cavity 41 in the rear end cover 4, and the pressure of the oil is gradually increased along with the rotation of the main screw 11 and is accumulated in the high-pressure seal cavity until the oil is pushed to the outlet cavity 32 of the pump body. The front end cover 5 is sleeved at one end of the main screw rod 11 and is tightly fixed with one end of the pump body, and the gland assembly 6 is arranged in the front end cover 5 so as to enable the front end cover 5 and the pump body 3 to be tightly pressed and seal the inner cavity of the pump body. Meanwhile, a sealing gasket 7 is arranged between the rear end cover 4 and the pump body 3 to seal the inner cavity of the pump body. During operation, the oil flows through two paths: the first main screw assembly 1 driven by the prime mover rotates to engage with the two slave screws 21 and cooperate with the axial inner cavity 31 of the pump body 3 to form a multi-stage sealed cavity, so that the conveying medium is sucked from the inlet cavity 41 of the rear end cover 4 and conveyed to the front section outlet cavity 32 of the pump body 3, and is output from the outlet 31 to an outlet pipeline for medium conveying. The second path is depressurized by the annular sunken groove 113 of the main screw 11 and flows into the front end cover assembly 5, and depressurized by the annular groove 213 of the screw assembly 2 and flows into the front end cover assembly 5 through the U-shaped step groove 222 and the oil return hole 221 on the right end face of the screw 21 to be collected in the low pressure sealing chamber 63, and finally flows back to the suction chamber 41 through the radial hole 112 and the axial long hole 111 of the main screw 11. Through tests, the screw pump improves the volumetric efficiency of the pump by controlling the oil quantity of high-pressure oil axially leaked to the low-pressure sealing cavity 63 through the main screw 11, so that the efficiency of the pump can be improved by 5% -8% compared with that of the conventional high-pressure screw pump; meanwhile, the abnormal abrasion of the screw rod caused by the actual deviation of the residual axial force of the screw rod and the theoretical deviation is solved by reducing the oil flow in the low-pressure sealing cavity 63 so as to reduce the dynamic pressure of the sealing cavity, the problems of unbalanced axial force and low volume efficiency of the main screw rod and the slave screw rod caused by large leakage amount of medium on the joint surface of a high-pressure oil overflowing part under a high-pressure working condition are solved, and the service life and the reliability of the screw pump are improved.

As shown in fig. 6, an axial inner cavity 31 and a radial outlet cavity 32 are formed in the pump body 3, and one main screw 11 and two slave screws 21 are engaged with each other and arranged in the axial inner cavity 31 to form the multi-stage high-pressure seal cavity. In operation, the high pressure seal chamber draws feed oil from the suction chamber 41 and delivers it to the radial outlet chamber 32, and out of the radial outlet chamber 32 into an outlet line.

In practical applications, a suction port is provided in the suction chamber 41 to suck oil, and the suction port may be arranged in parallel with the outlet of the radial outlet chamber.

As shown in fig. 3, the method further includes: a pressure ring 12; the main screw 11 is provided with the pressure ring 12, the material surface hardness of the pressure ring 12 is more than or equal to HRC42, the hardening depth is more than or equal to 2mm, and the roughness of the end face of the pressure ring 12 is controlled within Ra0.8.

Further, a main rod convex step 114 is arranged in the middle of the main screw rod 11.

As shown in fig. 4, a slave rod convex step 211 is provided at one end of the slave screw 21 and is engaged with the master rod convex step 114. In operation, the residual axial force of the slave screw 21 is transmitted from the master screw 11 to the master screw 114 via the slave screw projection step 211.

Further, a balance sleeve 22 is sleeved on the end portion of the slave screw 21, and a plurality of annular grooves 213 are formed in the outer circular surface of the slave screw 21 matched with the balance sleeve 22.

It should be noted that the axial limiting devices (the main rod convex step 114 and the slave rod convex step) of the main screw rod and the slave screw rod shorten the length of the screw rods, reduce the axial length of the high-pressure screw pump, and improve the space utilization rate of the screw pump.

In practical application, the conventional rolling bearing on the main screw is removed, the main rod convex step is matched with the front cover, the main screw compression ring is arranged, and the axial force balance of the screw is optimized, so that the vibration acceleration value (10-10kHz) of the screw pump under high pressure is reduced by 2-5 dB. The problem of screw pump vibration height is solved, the life-span and the reliability of pump have been promoted.

As shown in fig. 5, an oil return hole 221 and a U-shaped step groove 222 are formed in an end surface of the balance sleeve 22. In operation, high-pressure oil is decompressed through the annular groove 213 and flows out through the U-shaped step groove 222 and the oil return hole 221.

In practical application, as shown in fig. 4 and 5, a straight-line-shaped sink groove 212 penetrating through an end surface is formed in the end surface of the right end of the slave screw rod 21, and the straight-line-shaped sink groove 212 is communicated with the U-shaped step groove 222 and the oil return hole 221. In operation, high-pressure oil is decompressed through the annular groove 213 and flows out through the U-shaped step groove 222 and the oil return hole 221, and enters the low-pressure seal cavity 63. And the oil in the low-pressure seal chamber 63 flows back to the suction chamber 41 in the rear end cover 4 through the radial hole 112 and the axial long hole 111 of the main screw 11.

As shown in fig. 7, the front end cap includes: a cover 51, a first O-ring seal 52 and a second O-ring seal 53. The cover body 51 is provided with 2 oil holes 521 which axially penetrate through, and the oil holes 521 are communicated with the oil return hole 221 of the balance sleeve 22. The lid 51 with the contact surface of the pump body 3 is equipped with first seal groove, first O type sealing washer 52 sets up in the first seal groove for prevent by the oil liquid that oozes out in the balance sleeve 22 gap is excessive from the pump body anterior segment. The outer border of oilhole 521 is equipped with the second seal groove, second O type sealing washer 53 sets up in the second seal groove for prevent that high-pressure fluid from scurrying into oil gallery 22 department by balanced cover 22 and lid 51 fitting surface.

As shown in fig. 8, the capping assembly 6 includes: a gland 61 and an oil seal 62. The end face of the gland 61 contacting with the pump body is symmetrically provided with a plurality of radial step grooves 611. In operation, the oil flowing out of the annular groove 113 flows into the gland 61 through the radial step groove 611, and is isolated by the oil seal 62, so as to prevent the oil from flowing out of the main screw 11 and the gland 61. In practical application, 2-4 radial step grooves can be arranged.

Further, after the balance sleeve 22 is installed in the pump body, the end face of the balance sleeve 22 should be 0-0.30 mm higher than the end face of the counter bore of the pump body 3.

Therefore, the invention provides the high-efficiency low-vibration screw pump, the annular decompression grooves are additionally arranged on the main screw rod and the auxiliary screw rod, and the sealing elements are additionally arranged on the leakage points of the joint surface of high-pressure oil, so that the flow rate of the high-pressure oil flowing into the low-pressure sealing cavity is reduced, the pressure of the sealing cavity is reduced, and the abnormal abrasion of the screw rod caused by the actual and theoretical deviation of the residual axial force of the screw rod is solved. The problems of unbalanced axial force, low volumetric efficiency, easy damage and the like of the main screw and the slave screw under a high-pressure working condition are solved; through getting rid of conventional antifriction bearing on the main screw, utilize the protruding type step of mobile jib and the cooperation of protecgulum to and the setting of main screw clamping ring, the balanced optimization of cooperation screw rod axial force has solved the high problem of screw pump vibration, has promoted the life-span and the reliability of pump.

The construction, features and functions of the present invention have been described in detail with reference to the embodiments shown in the drawings, but the present invention is not limited to the embodiments shown in the drawings, and all equivalent embodiments modified or modified by the spirit and scope of the present invention should be protected without departing from the spirit of the present invention.

Claims

1. A high-efficiency low-vibration screw pump, comprising: the pump comprises a main screw (11), a slave screw (21), a pump body (3), a rear end cover (4), a front end cover (5) and a gland assembly (6);

the rear end cover (4) and the front end cover (5) are respectively arranged at two axial end parts of the pump body (3), the main screw (11) and the slave screw (21) are arranged in the pump body (3), and the main screw (11) and the slave screw (21) are meshed with each other to form a high-pressure sealing cavity;

the gland assembly (6) is sleeved in the front end cover (5) and forms a low-pressure sealing cavity (63) with the front end cover (5) and the main screw rod (11);

the outer circle section of the main screw (11) matched with the front end cover (5) is provided with uniformly distributed annular sinking grooves (113), the central shaft of the main screw (11) is provided with an axial long hole (111), a radial hole (112) close to the shaft seal installation position penetrates through the axial long hole (111), and the radial hole (112) is communicated with the low-pressure sealing cavity (63);

during operation, high-pressure oil in the high-pressure sealing cavity is decompressed through an annular sinking groove (113) of the main screw (11) and flows into the front end cover (5), then enters the low-pressure sealing cavity (63) and flows back to a suction cavity (41) in the rear end cover (4) through the radial hole (112) and the axial long hole (111).

2. An efficient low-vibration screw pump according to claim 1, wherein an axial inner cavity (31) and a radial outlet cavity (32) are provided in said pump body (3), one said main screw (11) and two said slave screws (21) are disposed in said axial inner cavity (31) in mesh to form said high-pressure sealed cavity in multiple stages;

in operation, the high-pressure seal chamber draws feed oil from the intake chamber (41) and feeds it to the radial outlet chamber (32) and out of the radial outlet chamber (32) into an outlet line.

3. The high efficiency, low vibration screw pump of claim 1, further comprising: a pressure ring (12);

the main screw (11) is provided with the pressing ring (12), the material surface hardness of the pressing ring (12) is more than or equal to HRC42, the hardening depth is more than or equal to 2mm, and the roughness of the end face of the pressing ring (12) is controlled within Ra0.8.

4. A high efficiency low vibration screw pump according to claim 3, wherein a main rod convex step (114) is provided at the middle of said main screw (11).

5. A high efficiency low vibration screw pump according to claim 4, wherein one end of said slave screw (21) is provided with a slave bar convex step (211) and is engaged with said master bar convex step (114);

in operation, the residual axial force of the slave screw (21) is transmitted from the master-rod convex step (114) to the master screw (11) through the slave-rod convex step (211).

6. A high efficiency low vibration screw pump according to claim 5, wherein the end of the slave screw (21) is sleeved with a balance sleeve (22), and a plurality of annular grooves (213) are provided on the outer circumferential surface of the slave screw (21) which is fitted with the balance sleeve (22).

7. The high-efficiency low-vibration screw pump according to claim 6, wherein an oil return hole (221) and a U-shaped step groove (222) are provided on an end surface of the balance sleeve (22);

during operation, high-pressure oil is decompressed through the annular groove (213) and then flows out through the U-shaped step groove (222) and the oil return hole (221).

8. The high efficiency, low vibration screw pump of claim 7, wherein said front end cap comprises: a cover body (51), a first O-shaped sealing ring (52) and a second O-shaped sealing ring (53);

the cover body (51) is provided with 2 oil holes (521) which penetrate through in the axial direction, and the oil holes (521) are communicated with an oil return hole (221) of the balance sleeve (22);

a first sealing groove is formed in the contact surface of the cover body (51) and the pump body (3), and the first O-shaped sealing ring (52) is arranged in the first sealing groove and used for preventing oil liquid seeped from the gap of the balance sleeve (22) from overflowing from the front section of the pump body (3);

oilhole (521) outside is along being equipped with the second seal groove, second O type sealing washer (53) set up in the second seal groove for prevent high-pressure fluid by oil gallery (22) department is scurried into with lid (51) fitting surface to balanced cover (22).

9. High efficiency low vibration screw pump according to claim 8, wherein said gland assembly (6) comprises: a gland (61) and an oil seal (62);

the end face of the gland (61) in contact with the pump body (3) is symmetrically provided with a plurality of radial step grooves (611);

in operation, the oil flowing out of the annular sink groove (113) flows into the gland (61) through the radial step groove (611), and is isolated by the oil seal (62) so as to avoid the oil flowing out of the main screw (11) and the gland (61).

10. The efficient low-vibration screw pump according to claim 9, wherein after the balance sleeve (22) is installed in the pump body (3), the end face of the balance sleeve (22) is 0-0.30 mm higher than the end face of a counter bore of the pump body (3);

the total fit clearance between the pressing ring (12) and the cover body (51) and the pressing cover (61) is 0.05-0.15 mm.