CN109667759B - Double-stage liquid ring vacuum pump and assembly method thereof - Google Patents
Double-stage liquid ring vacuum pump and assembly method thereof Download PDFInfo
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- CN109667759B CN109667759B CN201811601347.6A CN201811601347A CN109667759B CN 109667759 B CN109667759 B CN 109667759B CN 201811601347 A CN201811601347 A CN 201811601347A CN 109667759 B CN109667759 B CN 109667759B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C19/00—Rotary-piston pumps with fluid ring or the like, specially adapted for elastic fluids
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
- F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
- F04C29/06—Silencing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2240/00—Components
- F04C2240/80—Other components
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- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
The invention belongs to the field of liquid ring pumps, and particularly relates to a two-stage liquid ring vacuum pump and an assembly method thereof. The two-stage liquid ring vacuum pump is reasonable in structural design, and is provided with the two-stage compression cavities, the gas channel is not arranged on the middle wall, and the two-stage compression cavities are directly communicated through the external communicating pipe, so that in the assembling process, only the numerical values of the gaps L1 and L4 are required to be controlled, the gaps L2 and L3 are naturally formed by machining dimensions, the control is not required, the assembling gap is easy to ensure, the assembling process can be simplified, the assembling efficiency is improved, the using performance and the safety stability are improved on the premise that the extraction quantity and the vacuum degree are not influenced, and meanwhile, compared with the traditional two-stage pump, the production noise is greatly reduced, and the noise pollution is reduced. By the assembly method of the two-stage liquid ring vacuum pump, the two gaps L1 and L4 can be completely controlled, the assembly precision of the whole pump body is ensured, the assembly process is further simplified, and the assembly efficiency is improved.
Description
Technical Field
The invention relates to a two-stage liquid ring vacuum pump and an assembly method thereof, and belongs to the field of liquid ring pumps.
Background
With the continued development of the basic industry, vacuum equipment is required to have higher stability, particularly higher performance, efficiency and operational reliability during the high vacuum phase.
The traditional liquid ring pump is subjected to the temperature of working fluid in actual work, particularly loses the air pumping capacity in a high vacuum stage, and is easy to cause cavitation of an air cavity and damage parts because of high compression ratio.
Therefore, in order to solve the problem, the technical staff developed a two-stage compression vacuum pump (referred to as a two-stage pump for short), which is provided with two-stage compression chambers, wherein impellers and suction and exhaust discs (the structure is shown in fig. 7) are arranged in the two-stage compression chambers, the two-stage compression chambers are communicated through the intermediate wall 11' and the gas channel on the intermediate wall disc 18, and the suction process is divided into two stages, namely, two-stage compression is performed, so that stable suction speed can be realized, and cavitation effect is reduced. At present, the two-stage pump has gradually replaced the traditional liquid ring pump due to the advantages, and the application is wider.
However, in order to achieve the compression ratio, the conventional two-stage pump adopts an open impeller, and the front and rear gaps of the two impellers must be strictly controlled, specifically, the front and rear 2 gaps of the primary impeller 7' (i.e., the assembly gap L1 between the primary impeller 7' and the primary suction and exhaust disc 4', and the assembly gap L2 between the primary impeller 7' and the intermediate wall disc 18) and the front and rear 2 gaps of the secondary impeller 13' (i.e., the assembly gap L3 between the secondary impeller 13' and the intermediate wall 11', and the assembly gap L4 between the secondary impeller 13' and the secondary suction and exhaust disc 16 ') need to be controlled, so that 4 gap spaces in total need to be controlled, and l1=l2=l3=l4 need to be satisfied in the assembly process, so that high requirements are required for the machining precision and the assembly precision. At present, the sizes of the gaps are consistent, but in the actual assembly process, the assembly gaps are changed due to factors such as accumulated tolerance, assembly deformation and the like, so that adjustment is needed for 2 times or more, the assembly time length and efficiency are low, in the use process, the gaps are influenced by uncontrollable factors such as use deformation, use abrasion and the like, the consistency of 4 gaps is difficult to ensure, gaps with different sizes still appear in the later use process, the gaps are large, the air quantity and the vacuum degree are easy to reduce, the impeller damage problems such as abrasion, clamping and the like are easy to cause due to small gaps, the maintenance frequency is high, and in general, the gaps between any impeller and one side of the impeller are enlarged (or reduced) and the gaps between the impeller and the other side of the impeller are correspondingly reduced (or enlarged), so that the adverse effects are two-way. Therefore, how to reduce the assembly time and improve the assembly efficiency on the premise of ensuring that the extraction amount and the vacuum degree are not affected is a problem to be solved urgently at present.
Disclosure of Invention
The invention aims to solve the technical problems that: the two-stage liquid ring vacuum pump overcomes the defects in the prior art, and can reduce the assembly time, improve the assembly efficiency, and improve the service performance and the safety and stability; meanwhile, an assembling method of the two-stage liquid ring vacuum pump is provided.
The invention relates to a double-stage liquid ring vacuum pump, which comprises two stages of pump bodies assembled on the same main shaft, wherein the two stages of pump bodies share an intermediate wall, the first stage pump body consists of a first stage pump shell, a front pump cover and an intermediate wall, the second stage pump body consists of a second stage pump shell, a rear pump cover and the intermediate wall, the intermediate wall is fixedly connected with the first stage pump shell and the second stage pump shell at two sides of the intermediate wall, a limiting shaft sleeve is arranged on the main shaft, the intermediate wall is in clearance fit with the limiting shaft sleeve, a first stage impeller and a first stage suction and exhaust disc are arranged in the first stage pump body, a second stage impeller and a second stage suction and exhaust disc are arranged in the second stage pump body, the two impellers are arranged on the main shaft and are tightly attached to the limiting shaft sleeve, the two impellers and the limiting shaft sleeve rotate synchronously, the first stage suction and exhaust disc is fixedly connected with the first stage pump shell or the front pump cover, and the second stage suction and exhaust disc is fixedly connected with the second stage pump shell or the rear pump cover; the intermediate wall cuts off the pump cavity of the two-stage pump body; the two impellers are semi-closed impellers, the closed ends of the two impellers are close to the middle wall, a gap L1 is reserved between the end part of the open side of the first-stage impeller and the first-stage suction and exhaust disc, and a gap L4 is reserved between the end part of the open side of the second-stage impeller and the second-stage suction and exhaust disc; the primary air suction and exhaust disc, the primary impeller and the primary pump shell surround to form a primary compression cavity, the secondary air suction and exhaust disc, the secondary impeller and the secondary pump shell surround to form a secondary compression cavity, and the volume of the primary compression cavity is not smaller than that of the secondary compression cavity. The front pump cover is provided with a pump air inlet and a middle air outlet, a front partition plate is arranged in the front pump cover, a cavity surrounded by the front pump cover and the first-stage air suction and exhaust disc is divided into a first-stage air suction cavity and a first-stage air exhaust cavity which are mutually independent by the front partition plate, the first-stage air suction and exhaust disc is provided with a first-stage air inlet and a first-stage air outlet, the area of the first-stage air inlet is larger than that of the first-stage air outlet, the first-stage air inlet is communicated with the pump air inlet through the first-stage air suction cavity, and the first-stage air outlet is communicated with the middle air outlet through the first-stage air exhaust cavity. The rear pump cover is provided with a middle air inlet and a pump air outlet, and the middle air inlet is communicated with the middle air outlet on the front pump cover in the primary pump body through a communication pipe; the rear pump cover is provided with a rear baffle, a cavity surrounded by the rear pump cover and the secondary air suction and exhaust disc is divided into a secondary air suction cavity and a secondary air exhaust cavity which are mutually independent by the rear baffle, the secondary air suction and exhaust disc is provided with a secondary air inlet and a secondary air exhaust port, the area of the secondary air inlet is larger than that of the secondary air exhaust port, the secondary air inlet is communicated with the middle air inlet through the secondary air suction cavity, and the secondary air exhaust port is communicated with the pump air exhaust port through the secondary air exhaust cavity.
The specific working process of the two-stage liquid ring vacuum pump is as follows:
the gas enters the first-stage pump body through the pump air inlet, enters the first-stage compression cavity through the first-stage air suction cavity of the front pump cover and the first-stage air inlet on the first-stage air suction and exhaust disc, completes first-stage compression under the combined action of the first-stage impeller and the first-stage air exhaust port on the first-stage air suction and exhaust disc, enters the communicating pipe through the first-stage air exhaust cavity of the front pump cover and the middle air exhaust port, then enters the second-stage pump body through the communicating pipe and the middle air inlet, then enters the second-stage compression cavity through the second-stage air suction cavity of the rear pump cover and the second-stage air inlet on the second-stage air suction and exhaust disc, completes second-stage compression under the combined action of the second-stage impeller and the second-stage air exhaust port on the second-stage air suction and exhaust disc, and finally the compressed gas is discharged through the second-stage air exhaust cavity of the rear pump cover and the pump air exhaust port.
Compared with the traditional double-stage pump adopting an open impeller, the two-stage compression cavity is not communicated through the traditional middle wall and the gas channel on the middle wall disc, but is directly communicated through the external communicating pipe, so that the assembly gap L2 between the first-stage impeller and the middle wall and the assembly gap L3 between the second-stage impeller and the middle wall are not key factors influencing the pumping speed and the vacuum degree of the double-stage liquid ring vacuum pump, in the assembly process, only the numerical values of the gap L1 and the gap L4 are required to be controlled, the gaps L2 and the gaps L3 are naturally formed by processing sizes, and the control is not required (only the existence of the gaps between the two-stage impeller and the middle wall is required to be ensured), so that the assembly gaps L2 and the gaps L3 are easily ensured by adopting the limiting sleeve, and the assembly process can be simplified on the premise of ensuring that the assembly quantity and the vacuum degree are not influenced, and the assembly efficiency is improved, and the numerical values of the gaps L2 and L3 can be greatly (generally controlled to be 1-5 mm), so that the mechanical wear between the two-stage impellers can be completely avoided, and the mechanical wear is even reduced, and the mechanical wear is not caused.
Besides, as the traditional double-stage pump cannot strictly control L1=L2=L3=L4 in the use and maintenance process and controls each gap within 0.1-0.3mm, the impeller end face and the suction and exhaust disc are easy to grind, and larger noise can be generated in the use process, the double-stage liquid ring vacuum pump only needs to control the gaps at the two ends (namely L1 and L4) in the maintenance process, the operation is simple, the double-stage liquid ring vacuum pump can be assembled by a user by itself, and the phenomenon that the impeller end face and the corresponding side suction and exhaust disc are ground can not occur after the two gaps L1 and L4 are controlled, so that the production noise can be greatly reduced and the noise pollution is reduced.
In the invention, the shapes of the first-stage air inlet and the first-stage air outlet on the first-stage air suction and exhaust disc, and the second-stage air inlet and the second-stage air outlet on the second-stage air suction and exhaust disc can be designed into crescent shapes. Compared with the traditional air suction and exhaust ports with other shapes, the crescent air suction port has the advantages that the air suction area is gradually increased (consistent with the shape of the internal liquid ring) in the air suction process, the air suction is more stable, the air exhaust area of the crescent air exhaust port is gradually reduced (consistent with the shape of the internal liquid ring) in the air exhaust process, and the air exhaust is also more stable and smooth.
The values of the gap L1 and the gap L4 can be designed to be 0.1mm-0.3mm, and each impeller is ensured not to be contacted with the front side disc and the rear side disc through the values, and simultaneously, the free path of gas molecules in the working pressure range of the liquid ring pump is adapted, and the backflow is low. Preferably, the gap L1 has the same value as the gap L4, and is designed as a symmetrical gap so as to minimize the total backflow.
Preferably, the main shaft is provided with an ascending step, a limiting convex ring, a first descending step and a second descending step in sequence from front to back (namely from the front pump cover to the back pump cover); the front pump cover is assembled at the ascending step position through a bearing; the inner periphery of the disk surface of the primary air suction and exhaust disk, which is opposite to the primary impeller, is provided with a circular groove I with the depth of h1, the inner periphery of the end surface of the primary impeller, which is opposite to the primary air suction and exhaust disk, is provided with a circular groove II with the depth of h2, the primary impeller is assembled on the limiting convex ring from one side through the circular groove II, the primary air suction and exhaust disk is assembled on the limiting convex ring from the other side through the circular groove I, and the thickness h=h1+h2+L1 of the limiting convex ring; the inner periphery of the disc surface of the secondary suction and exhaust disc, which is opposite to the secondary impeller, is provided with a circular groove III, and the secondary suction and exhaust disc is assembled at the first descending step position through the circular groove III; the rear pump cover is assembled at the position of the second descending step through a bearing; the front pump cover is fixedly connected with the rear pump cover through a connecting rod. Through the setting of each step and spacing bulge loop on the main shaft, can guarantee the size of clearance L1, clearance L4 in the assembly process to ensure assembly accuracy, further guarantee the extraction quantity, the vacuum degree of whole pump and the safety and stability in the use, fix front pump cover and back pump cover as an organic whole through the connecting rod after the assembly is accomplished, in order to accomplish the connection assembly of whole pump body. Further preferably, the two ends of the connecting rod are provided with threaded sections, the corresponding connecting rod is provided with connecting through holes corresponding to the front pump cover and the rear pump cover, the two threaded sections respectively penetrate through the connecting through holes of the front pump cover and the rear pump cover and are provided with locking nuts, and the front pump cover and the rear pump cover are fixedly connected through the connecting rod and the two locking nuts.
Preferably, an annular groove I for positioning and assembling a first-stage air suction and exhaust disc is formed in the inner periphery of the joint of the first-stage pump shell and the front pump cover, and the first-stage air suction and exhaust disc is arranged in the annular groove I to realize fixed assembly; an annular groove II for positioning and assembling a secondary air suction and exhaust disc is formed in the inner periphery of the joint of the secondary pump shell and the rear pump cover, and the secondary air suction and exhaust disc is arranged in the two annular grooves II to realize fixed assembly; the intermediate wall is assembled with the primary pump shell and the secondary pump shell at the two sides by adopting the spigot.
The invention also provides an assembly method of the two-stage liquid ring vacuum pump, which comprises the following assembly steps:
(1) sequentially assembling the first-stage suction and exhaust disc and the front pump cover on the main shaft from the front end, and assembling the front end of the front pump cover with the main shaft through a front bearing;
(2) assembling the first-stage impeller and the first-stage pump shell on the main shaft from the rear end, and positioning the first-stage suction and exhaust disc through the first annular groove;
(3) assembling the limit shaft sleeve on the main shaft from the rear end, simultaneously assembling the intermediate wall and the primary pump shell into a whole, and enabling the intermediate wall to be in clearance fit with the limit shaft sleeve;
(4) assembling the secondary impeller and the secondary pump shell on the main shaft from the rear end, and assembling the secondary pump shell and the intermediate wall into a whole;
(5) the secondary air suction and exhaust disc and the rear pump cover are sequentially assembled on the main shaft from the rear end, and the rear end of the rear pump cover is assembled with the main shaft through a rear bearing;
(6) the front pump cover and the rear pump cover are connected and assembled into a whole through a connecting rod;
(7) the middle air inlet on the rear pump cover and the middle air outlet on the front pump cover are connected into a whole through the communication pipe.
By the assembly method of the two-stage liquid ring vacuum pump, the two gaps L1 and L4 can be completely controlled, the assembly precision of the whole pump body is ensured, the assembly process is further simplified, and the assembly efficiency is improved.
In order to facilitate production and manufacture, the two-stage liquid ring vacuum pump can also adopt an integrated molding of the primary pump shell, the intermediate wall and the secondary pump shell, and the assembly process steps are changed adaptively along with the structural change, so that the two-stage liquid ring vacuum pump is not described in detail.
Compared with the prior art, the invention has the following beneficial effects:
the double-stage liquid ring vacuum pump is reasonable in structural design, and can simplify the assembly process, improve the assembly efficiency, improve the use performance and the safety stability on the premise of ensuring that the extraction quantity and the vacuum degree are not influenced by changing the structural form of the whole pump body, and meanwhile, compared with the traditional double-stage pump, the double-stage liquid ring vacuum pump can greatly reduce the production noise and reduce the noise pollution; by the assembly method of the two-stage liquid ring vacuum pump, the two gaps L1 and L4 can be completely controlled, the assembly precision of the whole pump body is ensured, the assembly process is further simplified, and the assembly efficiency is improved.
Drawings
FIG. 1 is a cross-sectional view of the present invention;
FIG. 2 is a left side view of the primary suction and exhaust disk of FIG. 1;
FIG. 3 is a left side view of the front pump cover of FIG. 1;
FIG. 4 is a right side view of the secondary intake and exhaust disk of FIG. 1;
FIG. 5 is a right side view of the rear pump cap of FIG. 1;
FIG. 6 is a perspective view of the present invention;
fig. 7 is a schematic diagram of a conventional dual stage pump.
In the figure: 1. a main shaft; 2. a front bearing; 3. a front pump cover; 4. a first-stage suction and exhaust disc; 5. a lock nut; 6. a communicating pipe; 7. a primary impeller; 8. a first-stage pump shell; 9. a first stage compression chamber; 10. a limiting shaft sleeve; 11. an intermediate wall; 12. a connecting rod; 13. a secondary impeller; 14. a secondary compression chamber; 15. a secondary pump housing; 16. a second-stage suction and exhaust disc; 17. a rear pump cover;
1.1, ascending steps; 1.2, limiting convex rings; 1.3, a second descending step; 1.4, a first descending step;
3.1, middle exhaust port; 3.2, a pump air inlet; 3.3, front baffle; 3.4, a first-level air suction cavity; 3.5, a primary exhaust cavity;
4.1, a first-stage air inlet; 4.2, a first-stage exhaust port;
16.1, a secondary air inlet; 16.2, a secondary exhaust port;
17.1, pump exhaust port; 17.2, an intermediate air inlet; 17.3, a rear partition; 17.4, a secondary air suction cavity; 17.5, a secondary exhaust cavity;
4', a first-stage suction and exhaust disc; 7', a primary impeller; 11', an intermediate wall; 13', a secondary impeller; 16', a secondary suction and exhaust disc; 18. an intermediate wall disc.
Detailed Description
Embodiments of the invention are further described below with reference to the accompanying drawings:
as shown in fig. 1 to 6, the two-stage liquid ring vacuum pump according to the present invention comprises a primary pump body and a secondary pump body which are assembled on the same main shaft 1. Wherein:
the primary pump body is composed of a primary pump shell 8, a front pump cover 3 and an intermediate wall 11, the secondary pump body is composed of a secondary pump shell 15, a rear pump cover 17 and the intermediate wall 11, namely, the two-stage pump body shares the intermediate wall 11, the intermediate wall 11 is fixedly assembled with the primary pump shell 8 and the secondary pump shell 15 at two sides of the intermediate wall 11 by adopting a spigot, a limiting shaft sleeve 10 is arranged on the main shaft 1, and the intermediate wall 11 is in clearance fit with the limiting shaft sleeve 10. The intermediate wall 11 blocks the pump chambers of the two-stage pump body because there is no gas passage in the intermediate wall 11.
The primary pump body is internally provided with a primary impeller 7 and a primary air suction and exhaust disc 4, the primary impeller 7 is arranged on the main shaft 1 and is tightly attached to a limiting shaft sleeve 10, the inner periphery of the joint of the primary pump shell 8 and the front pump cover 3 is provided with a first annular groove for positioning and assembling the primary air suction and exhaust disc, the primary air suction and exhaust disc 4 is assembled in the first annular groove to realize fixed assembly so as to ensure fixed positions, meanwhile, the primary air suction and exhaust disc 4 is eccentrically assembled on the main shaft 1, the primary air suction and exhaust disc 4 is provided with a primary air inlet 4.1 and a primary air outlet 4.2, the area of the primary air inlet 4.1 is larger than that of the primary air outlet 4.2, the primary impeller 7 adopts a semi-closed impeller, the closed end of the primary impeller is close to the middle wall 11, and a gap L1 (the value of the gap L1 is 0.1-0.3 mm) exists between the end of the open side of the primary impeller and the primary air suction and exhaust disc 4; the primary suction and exhaust disc 4, the primary impeller 7 and the primary pump shell 8 surround to form a primary compression cavity 9; the front pump cover 3 is provided with a pump air inlet 3.2 and a middle air outlet 3.1, the front pump cover 3 is internally provided with a front baffle plate 3.3, a cavity surrounded by the front pump cover 3 and the first-stage air suction and exhaust disc 4 is divided into a first-stage air suction cavity 3.4 and a first-stage air exhaust cavity 3.5 which are mutually independent by the front baffle plate 3.3, the first-stage air inlet 4.1 is communicated with the pump air inlet 3.2 through the first-stage air suction cavity 3.4, and the first-stage air outlet 4.2 is communicated with the middle air outlet 3.1 through the first-stage air exhaust cavity 3.5;
the secondary pump body is internally provided with a secondary impeller 13 and a secondary air suction and exhaust disc 16, the secondary impeller 13 is arranged on the main shaft 1 and is tightly attached to the limiting shaft sleeve 10, the inner periphery of the joint of the secondary pump shell 15 and the rear pump cover 17 is also provided with a second annular groove for positioning and assembling the secondary air suction and exhaust disc, the secondary air suction and exhaust disc 16 is assembled in the second annular groove to ensure the fixed position, meanwhile, the secondary air suction and exhaust disc 16 is eccentrically assembled on the main shaft 1, the secondary air suction and exhaust disc 16 is provided with a secondary air inlet 16.1 and a secondary air outlet 16.2, the area of the secondary air inlet 16.1 is larger than that of the secondary air outlet 16.2, the secondary impeller 13 is also a semi-closed impeller, the closed end of the secondary impeller is also close to the main shaft sleeve 11, and a gap L4 exists between the end of the open side of the secondary air suction and exhaust disc 16; the secondary suction and exhaust disc 16, the secondary impeller 13 and the secondary pump shell 15 surround to form a secondary compression cavity 14, and the volume of the secondary compression cavity 14 is smaller than that of the primary compression cavity 9; the rear pump cover 17 is provided with an intermediate air inlet 17.2 and a pump air outlet 17.1, the rear pump cover 17 is internally provided with a rear partition plate 17.3, a cavity surrounded by the rear pump cover 17 and the secondary air suction and exhaust disc 16 is divided into a secondary air suction cavity 17.4 and a secondary air exhaust cavity 17.5 which are mutually independent by the rear partition plate 17.3, the secondary air inlet 16.1 is communicated with the intermediate air inlet 17.2 through the secondary air suction cavity 17.4, and the secondary air outlet 16.2 is communicated with the pump air outlet 17.1 through the secondary air exhaust cavity 17.5;
the primary impeller 7, the secondary impeller 13 and the limiting shaft sleeve 10 all synchronously rotate with the main shaft 1, and in the embodiment, the two-stage impellers are separated through the limiting shaft sleeve 10, so that gaps are reserved between the two-stage impellers and the intermediate wall 11;
the middle air inlet 17.2 on the middle and rear pump covers 17 of the secondary pump body is communicated with the middle air outlet 3.1 on the front pump cover 3 of the primary pump body through a communication pipe 6;
for convenience of description, the end of the front pump cover 3 is defined as the front end of the main shaft 1, the end of the rear pump cover 17 is defined as the rear end of the main shaft 1, and the main shaft 1 is sequentially provided with an ascending step 1.1, a limiting convex ring 1.2, a first descending step 1.4 and a second descending step 1.3 from front to back (i.e. from the front pump cover 3 to the rear pump cover 17); the front pump cover 3 is assembled at the position of the ascending step 1.1 through a bearing; the first-stage suction and exhaust disc 4 is provided with a circular ring groove I with the depth of h1 in the disc surface opposite to the first-stage impeller 7, the first-stage impeller 7 is provided with a circular ring groove II with the depth of h2 in the end surface opposite to the first-stage suction and exhaust disc 4, the first-stage impeller 7 is assembled on the limiting convex ring 1.2 from one side through the circular ring groove II, the first-stage suction and exhaust disc 4 is assembled on the limiting convex ring 1.2 from the other side through the circular ring groove I, and the thickness h=h1+h2+L1 of the limiting convex ring 1.2; the inner periphery of the disk surface of the secondary suction and exhaust disk 16, which is opposite to the secondary impeller 13, is provided with a circular groove III, and the secondary suction and exhaust disk 16 is assembled at the 1.4 position of the first descending step through the circular groove III; the rear pump cover 17 is assembled at the position of the second descending step 1.3 through a bearing; the two ends of the connecting rod 12 are provided with threaded sections, connecting through holes are correspondingly formed in the front pump cover 3 and the rear pump cover 17 corresponding to the connecting rod 12, the two threaded sections respectively penetrate through the connecting through holes of the front pump cover 3 and the rear pump cover 17 and are provided with locking nuts 5, and the front pump cover 3 and the rear pump cover 17 are fixedly connected through the connecting rod 12 and the two locking nuts 5.
During assembly, it is ensured that the value of the gap L4 is the same as the value of the gap L1.
In the embodiment, the shapes of the air inlet and outlet ports on the two-stage air suction and exhaust discs are crescent; the outer diameters of the two-stage impellers are the same, and the axial length of the first-stage impeller 7 is larger than that of the second-stage impeller 13.
The specific working process of the two-stage liquid ring vacuum pump in this embodiment is as follows:
the gas enters the first-stage pump body through the pump air inlet 3.2, enters the first-stage compression cavity 9 through the first-stage air suction cavity 3.4 of the front pump cover 3 and the first-stage air inlet 4.1 on the first-stage air suction and exhaust disc 4, completes the first-stage compression under the combined action of the first-stage impeller 7 and the first-stage air exhaust port 4.2 on the first-stage air suction and exhaust disc 4, enters the communication pipe 6 through the first-stage air exhaust cavity 3.5 of the front pump cover 3 and the middle air exhaust port 3.1, then enters the second-stage pump body through the communication pipe 6 and the middle air inlet 17.2, then enters the second-stage compression cavity 14 through the second-stage air suction cavity 17.4 of the rear pump cover 17 and the second-stage air inlet 16.1 on the second-stage air suction and exhaust disc 16, completes the second-stage compression under the combined action of the second-stage impeller 13 and the second-stage air exhaust port 16.2 on the second-stage air suction and exhaust disc 16, and finally the compressed gas is discharged through the second-stage air exhaust cavity 17.5 of the rear pump cover 17 and the pump air exhaust port 17.1.
Compared with the conventional two-stage pump adopting an open impeller, the two-stage compression cavity is not communicated through the conventional intermediate wall and the gas channel on the intermediate wall disc, but is directly communicated through the external communication pipe 6, so that the assembly gap L2 between the first-stage impeller 7 and the intermediate wall 11 and the assembly gap L3 between the second-stage impeller 13 and the intermediate wall 11 are not key factors influencing the pumping speed and the vacuum degree of the two-stage liquid ring vacuum pump, in the assembly process, only the numerical values of the gap L1 and the gap L4 are required to be controlled, the gaps L2 and L3 are naturally formed by the machining size without control, the assembly gap is easy to ensure, the assembly process can be simplified on the premise of ensuring that the pumping quantity and the vacuum degree are not influenced, the assembly efficiency is improved, and the use performance and the safety and the stability are improved. Meanwhile, in the maintenance process of the two-stage liquid ring vacuum pump, only the gaps (namely L1 and L4) at the two ends are required to be controlled, the operation is simple, the two-stage liquid ring vacuum pump can be assembled by a user, and the phenomenon that the end face of an impeller and a corresponding side suction and exhaust disc are ground can not occur after the two gaps L1 and L4 are controlled well, so that the two-stage liquid ring vacuum pump has the advantage of low noise compared with the traditional two-stage pump.
The assembly method of the two-stage liquid ring vacuum pump specifically comprises the following steps:
(1) the primary suction and exhaust disc 4 and the front pump cover 3 are sequentially assembled on the main shaft 1 from the front end, and the front end of the front pump cover 3 is assembled with the main shaft 1 through the front bearing 2;
(2) the primary impeller 7 and the primary pump shell 8 are assembled on the main shaft 1 from the rear end, and the primary suction and exhaust disc 4 is positioned through the first annular groove;
(3) assembling the limit shaft sleeve 10 on the main shaft 1 from the rear end, simultaneously assembling the intermediate wall 11 and the primary pump shell 8 into a whole through a spigot, and enabling the intermediate wall 11 to be in clearance fit with the limit shaft sleeve 10;
(4) assembling the secondary impeller 13 and the secondary pump casing 15 on the main shaft 1 from the rear end, and assembling the secondary pump casing 15 and the intermediate wall 11 into a whole through a spigot;
(5) the secondary suction and exhaust disc 16 and the rear pump cover 17 are sequentially assembled on the main shaft 1 from the rear end, and the rear end of the rear pump cover 17 is assembled with the main shaft 1 through a rear bearing;
(6) the front pump cover 3 and the rear pump cover 17 are connected and assembled into a whole through the connecting rod 12;
(7) the middle air inlet 17.2 on the rear pump cover 17 and the middle air outlet 3.1 on the front pump cover 3 are connected into a whole through a communication pipe 6.
By the assembly method of the two-stage liquid ring vacuum pump, the two gaps L1 and L4 can be completely controlled, so that the assembly precision of the whole pump body is ensured, the assembly process is further simplified, and the assembly efficiency is improved.
With the extraction amount of 3m 3 A two-stage liquid ring vacuum pump per min is taken as an example,
1) The processing precision control is reduced (parameters) after the design is changed, the working time is reduced by 30%, and the rejection rate is reduced by 60%;
2) The assembly process only needs to adjust the gap L1 and the gap L4, and the assembly working time is reduced by 20%;
3) In the testing process, the impeller is not damaged due to contact and scraping of the impeller and the air suction and exhaust disc, the gap does not need to be adjusted for 2 times, main parameters such as the forefront performance pumping quantity, the vacuum degree, the consumed power and the like of the vacuum pump are not changed, and the reliability is increased.
After the two-stage liquid ring vacuum pump in the embodiment is supplied to a plurality of pharmaceutical and refining enterprises for use, the embodiment is simpler to use and maintain through the use feedback in the concentration process, and accessories are easy to repair and manufacture; in terms of performance, noise reduction, vacuum, gas flow, and power consumption are unchanged.
Claims (7)
1. The utility model provides a doublestage liquid ring vacuum pump, including assembling the two-stage pump body on same main shaft (1), two-stage pump body sharing interwall (11), the one-stage pump body comprises one-level pump housing (8), preceding pump cover (3), interwall (11), the secondary pump body comprises secondary pump shell (15), back pump cover (17), interwall (11), one-level pump housing (8) of interwall (11) and its both sides, secondary pump shell (15) fixed connection, spacing axle sleeve (10) are installed on main shaft (1), interwall (11) and spacing axle sleeve (10) clearance fit, be equipped with one-level impeller (7) and one-level suction and exhaust disc (4) in the one-level pump body, be equipped with secondary impeller (13) and secondary suction and exhaust disc (16) in the secondary pump body, two impellers are all installed on main shaft (1) and are pasted tight spacing axle sleeve (10) installation, two impellers and spacing axle sleeve (10) all rotate with main shaft (1) in step, one-level suction and exhaust disc (4) and pump housing (8) or preceding pump cover (3) fixed connection, secondary suction and exhaust disc (16) and secondary pump housing (15) or back fixed connection, characterized in that: the intermediate wall (11) cuts off the pump cavities of the two-stage pump body; the two impellers are semi-closed impellers, the closed ends of the two impellers are close to the intermediate wall (11), a gap L1 is reserved between the end part of the open side of the primary impeller (7) and the primary air suction and exhaust disc (4), and a gap L4 is reserved between the end part of the open side of the secondary impeller (13) and the secondary air suction and exhaust disc (16); the primary air suction and exhaust disc (4), the primary impeller (7) and the primary pump shell (8) surround to form a primary compression cavity (9), the secondary air suction and exhaust disc (16), the secondary impeller (13) and the secondary pump shell (15) surround to form a secondary compression cavity (14), and the volume of the primary compression cavity (9) is not smaller than that of the secondary compression cavity (14);
the front pump cover (3) is provided with a pump air inlet (3.2) and a middle air outlet (3.1), the front pump cover (3) is internally provided with a front partition plate (3.3), a cavity surrounded by the front pump cover (3) and the first-stage air suction and exhaust disc (4) is divided into a first-stage air suction cavity (3.4) and a first-stage air exhaust cavity (3.5) which are mutually independent by the front partition plate (3.3), the first-stage air suction and exhaust disc (4) is provided with a first-stage air inlet (4.1) and a first-stage air exhaust port (4.2), the area of the first-stage air inlet (4.1) is larger than that of the first-stage air exhaust port (4.2), the first-stage air inlet (4.1) is communicated with the pump air inlet (3.2) through the first-stage air suction cavity (3.4), and the first-stage air exhaust port (4.2) is communicated with the middle air exhaust port (3.1) through the first-stage air exhaust cavity (3.5).
The rear pump cover (17) is provided with an intermediate air inlet (17.2) and a pump air outlet (17.1), and the intermediate air inlet (17.2) is communicated with the intermediate air outlet (3.1) on the front pump cover (3) in the primary pump body through a communication pipe (6); the rear pump cover (17) is internally provided with a rear partition plate (17.3), a cavity surrounded by the rear pump cover (17) and the secondary air suction and exhaust disc (16) is divided into a secondary air suction cavity (17.4) and a secondary air exhaust cavity (17.5) which are mutually independent by the rear partition plate (17.3), the secondary air suction and exhaust disc (16) is provided with a secondary air inlet (16.1) and a secondary air exhaust port (16.2), the area of the secondary air inlet (16.1) is larger than that of the secondary air exhaust port (16.2), the secondary air inlet (16.1) is communicated with the middle air inlet (17.2) through the secondary air suction cavity (17.4), and the secondary air exhaust port (16.2) is communicated with the pump air exhaust port (17.1) through the secondary air exhaust cavity (17.5);
the shapes of the primary air inlet (4.1) and the primary air outlet (4.2) on the primary air suction and exhaust disc (4) are crescent;
the shapes of the secondary air inlet (16.1) and the secondary air outlet (16.2) on the secondary air suction and exhaust disc (16) are crescent;
the main shaft (1) is sequentially provided with an ascending step (1.1), a limiting convex ring (1.2), a first descending step (1.4) and a second descending step (1.3) from front to back; the front pump cover (3) is assembled at the position of the ascending step (1.1) through a bearing; the first-stage air suction and exhaust disc (4) is provided with a first circular groove with the depth of h1 in the inner periphery of the disc surface opposite to the first-stage impeller (7), the first-stage impeller (7) is provided with a second circular groove with the depth of h2 in the inner periphery of the end surface opposite to the first-stage air suction and exhaust disc (4), the first-stage impeller (7) is assembled on the limiting convex ring (1.2) from one side through the second circular groove, the first-stage air suction and exhaust disc (4) is assembled on the limiting convex ring (1.2) from the other side through the first circular groove, and the thickness h=h1+h2+L1 of the limiting convex ring (1.2); the inner periphery of the disc surface, opposite to the secondary impeller (13), of the secondary air suction and exhaust disc (16) is provided with a circular groove III, and the secondary air suction and exhaust disc (16) is assembled at the position of the first descending step (1.4) through the circular groove III; the rear pump cover (17) is assembled at the position of the second descending step (1.3) through a bearing; the front pump cover (3) and the rear pump cover (17) are fixedly connected through a connecting rod (12).
2. The dual-stage liquid ring vacuum pump of claim 1, wherein: the value of the gap L1 is 0.1mm to 0.3mm.
3. The dual-stage liquid ring vacuum pump of claim 1, wherein: the value of the gap L4 is 0.1mm-0.3mm.
4. A dual-stage liquid ring vacuum pump as defined in any one of claims 1-3 wherein: the value of the gap L1 is the same as the value of the gap L4.
5. The dual-stage liquid ring vacuum pump of claim 1, wherein: the two ends of the connecting rod (12) are provided with threaded sections, connecting through holes are correspondingly formed in the front pump cover (3) and the rear pump cover (17) corresponding to the connecting rod (12), and the two threaded sections respectively penetrate through the connecting through holes of the front pump cover (3) and the rear pump cover (17) and are provided with locking nuts (5).
6. The dual-stage liquid ring vacuum pump of claim 1, wherein: an annular groove I for positioning and assembling a primary air suction and exhaust disc is formed in the inner periphery of the joint of the primary pump shell (8) and the front pump cover (3), and the primary air suction and exhaust disc (4) is arranged in the two annular grooves I to realize fixed assembly; an annular groove II for positioning and assembling a secondary air suction and exhaust disc is formed in the inner periphery of the joint of the secondary pump shell (15) and the rear pump cover (17), and the secondary air suction and exhaust disc (16) is arranged in the two annular grooves II to realize fixed assembly; the intermediate wall (11) and the primary pump shell (8) and the secondary pump shell (15) at the two sides of the intermediate wall are assembled by adopting a spigot.
7. A method of assembling a dual-stage liquid ring vacuum pump as defined in claim 6, wherein: the method specifically comprises the following assembly steps:
(1) the first-stage suction and exhaust disc (4) and the front pump cover (3) are sequentially assembled on the main shaft (1) from the front end, and the front end of the front pump cover (3) is assembled with the main shaft (1) through the front bearing (2);
(2) the primary impeller (7) and the primary pump shell (8) are assembled on the main shaft (1) from the rear end, and the primary suction and exhaust disc (4) is positioned through the first annular groove;
(3) assembling a limit shaft sleeve (10) on the main shaft (1) from the rear end, simultaneously assembling the intermediate wall (11) and the primary pump shell (8) into a whole, and enabling the intermediate wall (11) to be in clearance fit with the limit shaft sleeve (10);
(4) assembling the secondary impeller (13) and the secondary pump shell (15) on the main shaft (1) from the rear end, and assembling the secondary pump shell (15) and the intermediate wall (11) into a whole;
(5) the secondary air suction and exhaust disc (16) and the rear pump cover (17) are sequentially assembled on the main shaft (1) from the rear end, and the rear end of the rear pump cover (17) is assembled with the main shaft (1) through a rear bearing;
(6) the front pump cover (3) and the rear pump cover (17) are connected and assembled into a whole through the connecting rod (12);
(7) the middle air inlet (17.2) on the rear pump cover (17) and the middle air outlet (3.1) on the front pump cover (3) are connected into a whole through the communication pipe (6).
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| CN201811601347.6A CN109667759B (en) | 2018-12-26 | 2018-12-26 | Double-stage liquid ring vacuum pump and assembly method thereof |
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| CN109667759A (en) | 2019-04-23 |
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Inventor after: Huang Zhiting Inventor after: Xu Fajian Inventor before: He Hongxia Inventor before: Xu Fajian Inventor before: Gong Zelong Inventor before: Huang Zhiting |
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Effective date of registration: 20230413 Address after: 255200 no.296, xiwaihuan Road, Boshan District, Zibo City, Shandong Province Applicant after: Zibo Vacuum Equipment Plant Co.,Ltd. Address before: Boshan District of Shandong city in Zibo province 255200 Shuangshan Street No. 160 Applicant before: Huang Zhiting |
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