CN204553260U - A kind of bidirection air intake multistage centrifugal compressor - Google Patents

Abstract

A two-way intake multi-stage centrifugal compressor, which mainly includes: main shaft, impeller, spacer, thrust disc, balance disc, diaphragm coupling, diffuser, reflux device, bend, inlet and outlet volute, Seals, bearing group parts, housings, etc., are characterized in that: (1) multiple cascaded impellers are used, and between two adjacent impellers, the blades of the latter impeller are set to deflect to a certain extent relative to the blades of the previous impeller. angle; (2) The impellers are divided into two groups, and the two sets of impellers are installed on the same main shaft in opposite directions. When the main shaft rotates, the airflow direction of the two sets of impellers is opposite; The combination of diffusers, the vaneless diffuser is in the front and the vane diffuser is in the rear; (4) the inlet channel with adjustable guide vane angle composed of inner ring, outer ring, side plate and guide vane is adopted; ( 5) The inlet and outlet volute chambers with reinforcing ribs on both sides of the partition are adopted; (6) The gas seal body assembled by split seal; (7) The oil seal group structure with a certain tapered slope on the inner wall of the sealing ring is adopted; (8) The air intake mode adopts the air intake structure of two air inlets; (9) the air outlet mode also adopts the air outlet structure of two air outlets.

Description

A Bidirectional Inlet Multistage Centrifugal Compressor

technical field

The utility model belongs to the technical field of centrifugal compressors, in particular to a centrifugal compressor for bidirectionally transporting multi-component special fluids in the technical field of chemical industry.

Background technique

In chemical enterprises, two or more fluids with different components often enter the reaction tank to undergo chemical reactions at a certain temperature and pressure. The temperature can be adjusted by the heat exchanger on the outer shell of the reaction tank, while the pressure must be provided by a compressor. However, these fluids need to have a certain pressure before entering the reaction tank, but they cannot be mixed in advance, so that multiple compressors are required to pressurize the fluids of each component respectively, which not only needs to increase the investment of equipment; It is also difficult to match the pressure of each component fluid.

At present, the centrifugal compressors used by most petrochemical enterprises can be divided into horizontally split compressors, cylindrical compressors (that is, vertically split), and axial flow compressors. These types of compressors deliver The gas enters the compressor from the inlet at one end, and is output from the outlet at the other end after being pressurized by the rotor, and then enters the user's process pipeline. Even if there are two-stage or three-stage compressors, the gas temperature If it is too high, the gas passes through the cooler to achieve cooling, and then returns to the compressor to increase the pressure.

In a centrifugal compressor, the main components are the working wheel (impeller) and the diffuser and reflux device matched with it. After the gas passes through the impeller, it will obtain a lot of kinetic energy. In order to effectively use this part of energy, after the impeller Equipped with diffuser. Diffusers are divided into vaneless diffusers and vane diffusers according to their structure, which play a great role in improving the performance of compressors.

How to effectively improve the efficiency of multi-stage centrifugal compressors, reduce manufacturing costs, and provide a high-efficiency compressor that can be stably driven within a wide operating range has become the goal pursued by scientists and technicians in this technical field.

Chinese patent CN1015489B discloses a "multi-stage centrifugal compressor", which is characterized in that: each impeller of the compressor and the diffuser connected to it form a first stage, and the compressor has at least four centrifugal rotors and at least four guides. Vane diffuser (i.e. vane diffuser). In the guide vane diffuser mentioned above, the ratio of the guide vane leading edge radius of the former diffuser to the rotor outlet radius is greater than the same ratio of the latter diffuser, and the latter diffuser is farther from the discharge side than the stated The previous diffuser is near. In addition to the stages described with vane-type diffusers, there is at least one stage of vaneless diffusers. Since the rotary desulfurization in the diffuser is generated when the backflow develops and forms a backflow zone that rotates in the diffuser, and the guide vane diffuser is installed inside the position where the backflow begins to appear in the vaneless diffuser. The leading edge of the vane has the function of preventing backflow. In this way, the initial backflow in the reflux device is suppressed, and the occurrence of rotary desulfurization is avoided, so that the compressor can achieve high efficiency and can operate in a wide range. work in the range.

Chinese patent ZL92111548.2 discloses a "centrifugal compressor", which is characterized in that: the blades of the vane diffuser are divided into two groups, and the first group of blades has an air inlet that is inclined in the downstream direction and deviates from the side plate and extends toward the core plate side, the second group of blades has an inlet edge perpendicular to the above-mentioned fluid direction, and the first group and the second group of blades are configured in a mixed manner; at the same time, a plurality of auxiliary blades are also provided, and the chord length of each auxiliary blade is larger than that of each The chord length of the blades is short, and the auxiliary blades are arranged in a radially inward position, one surface of which faces one blade; the auxiliary blades are also divided into two groups, the first group has a slope in the downstream direction and deviates from the above-mentioned side plate towards the above-mentioned core The inlet edge of the plate extension; the second group has the inlet edge perpendicular to the above-mentioned flow direction, and the two sets of blades are also configured in a mixed manner. The vicinity of the tongue of the scroll-shaped airflow passage of the above-mentioned blade and the auxiliary vane is sparse; and the part of the above-mentioned passage far away from the above-mentioned tongue is dense; and the vicinity of the tongue is an area that includes the above-mentioned tongue and corresponds to not more than the entire The general area of the circumference. This design places the inlet side closer to the impeller, which minimizes or prevents reverse flow, thereby preventing surge even in the low air velocity range. The non-uniform configuration of the blades together with the auxiliary blades to form a sparse zone and a dense zone also minimizes the occurrence of rotational stall.

Chinese invention patent application CN102434491A discloses a "centrifugal compressor". The guide vanes of the vane diffuser are composed of long and short guide vanes with the same trailing edge radius but different lengths. At least one short guide vane is arranged between them, and the rectification effect of the short guide vane is used to improve the performance of the compressor.

The focal points of the above-mentioned inventions all focus on the diffuser. However, the more important part of the centrifugal compressor is its impeller (impeller). In a sense, the blade and the diffuser are a pair of mutual cooperation. The main body of the contradiction, to improve the performance of the compressor, it is necessary to comprehensively consider their structure and interrelationship. In addition, using the same compressor to compress two fluids will increase the overall utilization of the compressor, and the efficiency of the compressor will be improved to a higher level. In summary, these are the focus of our research work.

Contents of the invention

The purpose of the utility model is to find a high-efficiency multi-stage centrifugal compressor with two-way air intake and stable driving within a wide working range. We start by studying the flow of gas in the impeller. When the number of blades is limited, due to the influence of the circulation motion in the blade channel, there is a circulation velocity (ie, axial vortex) at the exit of the impeller that is opposite to the peripheral velocity, making the gas flow The relative velocity of is deflected by an angle towards the reverse direction at the exit. If between two adjacent blades, the blades of the latter impeller are also offset by a corresponding angle relative to the blades of the previous impeller, the existence of the axial vortex can be significantly reduced. Correspondingly, the design of the diffuser has been improved. In order to ensure the uniform flow of air in the volute channel, we not only considered the design of the improved radial inlet guide vane regulator, but also studied the structure of the two-way inlet and outlet volute.

The utility model provides a two-way intake multistage centrifugal compressor, which mainly includes: a main shaft, an impeller, a spacer, a thrust disc, a balance disc, a diaphragm coupling, a diffuser, a reflux device, a bend, The inlet and outlet volute chambers, seals, bearing group components, shells, etc., are characterized in that:

(1) Using multiple cascaded impellers, between two adjacent impellers, the blades of the latter impeller are set to deflect at a certain angle relative to the blades of the previous impeller;

(2) The impellers are divided into two groups, and the two sets of impellers are installed on the same main shaft in opposite directions. When the main shaft rotates, the airflow direction of the two sets of impellers is opposite;

(3) The diffuser adopts a combination of a vaneless diffuser and a vane diffuser, the vaneless diffuser is in front and the vane diffuser is behind;

(4) Adopt the inlet channel with adjustable guide vane angle composed of inner ring, outer ring, side plate and guide vane;

(5) The inlet and outlet volute chambers with reinforcing ribs on both sides of the partition are adopted;

(6) The air seal body of the overall assembly of the split seal;

(7) The oil seal group structure with a certain tapered slope on the inner wall of the sealing ring is adopted;

(8) The air intake method adopts two symmetrical air intake structures;

(9) The air outlet method also adopts two symmetrically arranged air outlet inlet structures.

In the two-way intake multi-stage centrifugal compressor of the present utility model, between the two adjacent impellers, the blade of the latter impeller is set to deflect at a certain angle relative to the blade of the previous impeller; : 5 to 15 degrees; for forward curved blades: 5 to 15 degrees; for radial blades: 5 to 30 degrees.

In the bi-directional air intake multistage centrifugal compressor of the present utility model, the air inlet channel with adjustable guide vane angle is additionally provided with a guide positioning pin, a positioning pin for changing the guide vane angle, and a guide vane rotation center pin.

In the bidirectional air intake multistage centrifugal compressor of the present utility model, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition are spliced by upper and lower parts, and the two sides of the partition are respectively equipped with In the volute type volute chamber flow channel, stiffener plates are distributed between the two side plates; there is no annular stiffener on the mid-parting surface between the upper and lower parts of the partition.

The bidirectional air intake multistage centrifugal compressor of the present utility model, said split seal overall assembly, includes the upper and lower sealing body, the upper sealing body is designed with sealing teeth and sealing cavity, and the sealing ring passes through the sealing ring on the lower sealing body. The tight fit of the fine thread secures the upper and lower sealing bodies.

The bi-directional intake multi-stage centrifugal compressor of the utility model adopts the oil seal group structure with a certain tapered slope on the inner wall of the sealing ring. Shaped or concave-convex patterns, on which there is a Babbitt alloy layer.

In the bi-directional air intake multi-stage centrifugal compressor of the present utility model, the air intake mode adopts a two-way air intake intake structure, and the lower casing of the compressor has four air ports, that is, two as a group to complete a Compression of fluid; while the other group of gas ports can also complete the compression of one fluid at the same time, and the two fluids are respectively installed in two containers.

In the bidirectional air intake multi-stage centrifugal compressor of the utility model, the air outlet method adopts a two-way air outlet outlet structure, and the lower casing of the compressor has two air outlets, which are arranged on the middle shoulder of the lower casing of the compressor. parts.

The utility model is a combined invention and creation, which not only synthesizes a number of utility model patents of the company, but also adds the designer's innovative design of the impeller and diffuser, and adopts the design of the two-way air inlet and outlet structure, which is more It is suitable for the needs of medium and small petrochemical and chemical enterprises. It not only enables the multi-stage centrifugal compressor with two-way air inlet to be stably driven within a wide working range, but also enables the compressor to better adapt to various Different working environments and working media are well received by users and welcomed by the majority of users.

Description of drawings

Fig. 1 is the overall sectional view of the two-way intake multi-stage centrifugal compressor of the present invention; Fig. 2 is the front view of the inlet duct with adjustable guide vane angle; Schematic diagram of the structure of the two sides of the inlet and outlet volute of the reinforcement rib; Figure 5 is the front view of the air seal body assembled by the split seal; Figure 6 is the structural diagram of the oil seal group structure; Figure 7 is the two-way intake multi-stage centrifugal compressor schematic diagram of the appearance.

Detailed ways

The bidirectional intake multistage centrifugal compressor of the present invention will be further described and supplemented below in conjunction with the accompanying drawings.

As shown in Figure 1, the bidirectional intake multistage centrifugal compressor of the present invention includes a main shaft 1, an impeller 2, a spacer 3, a thrust disc 4, an air inlet 5, an inlet and outlet volute 6, and a diaphragm coupling 7 , curve 8, diffuser 9, reflux device 10, balance plate 11, gas seal body 12, oil seal group 13, there are at least two impellers, which are divided into two groups, and the two groups of impellers are reversely connected in series on the main shaft , between two adjacent blades 21, the blade of the latter impeller is set to deflect a certain angle relative to the blade of the previous impeller; for the backward curved blade: 5 ~ 15 degrees; for the forward curved blade: 5 ~ 15 degrees; 5 to 30 degrees for radial blades. The diffusers of the two-way intake multistage centrifugal compressor of the utility model are also divided into two groups, one group is a vaneless diffuser 91, and the other group is a vane diffuser 92, and the configuration of two groups of intervals, each The vaneless diffuser is followed by a vaned diffuser. The lower casing of the compressor has four air ports, which are respectively two air inlets, which are arranged at the outer end of the compressor; two air outlets, which are arranged at the middle part of the compressor.

As shown in Figure 2, the bi-directional intake multistage centrifugal compressor of the present utility model adopts the inlet channel with adjustable guide vane angle, which includes side plate 51, inner ring 52, outer ring 53, guide vane 54, guide vane positioning Pin 55, change guide vane angle positioning pin 56 and guide vane rotation center pin 57. The outer ring is fixed on the inner ring by the guide positioning pin, the positioning pin is inserted into the outer ring when the guide vane angle is changed, the guide vane rotation center pin is inserted into the inner ring and the side plate, the guide vane is slidingly connected with the guide vane angle positioning pin, and the outer ring Drive the positioning pin to change the angle of the guide vane, and the positioning pin to change the angle of the guide vane drives the guide vane to rotate around the center pin, so that the angle of the guide vane of the inlet can be adjusted.

As shown in Figure 3 and Figure 4, the utility model adopts the inlet and outlet volute chambers with reinforcement ribs on both sides of the outlet partition, that is, the structure of the middle partition into and out of the air chamber, which includes: the inlet and outlet volute 61 on the partition, the partition The inlet and outlet volute chamber 62 under the plate, the reinforcing rib plate 63, the ring rib 64 of the middle split surface, the flow channel 65, and the volute chamber outlet 66. First, the upper and lower inlet and outlet volutes are made of steel respectively, and then the steel is respectively pressed and processed into a stiffener plate and a ring rib in the middle split surface. The lower inlet and outlet volutes are welded together, and finally made into inlet and outlet volutes with reinforcing ribs on both sides of the outlet partition.

As shown in Figure 5, the gas seal body of the present invention is composed of the upper part 121 of the sealing body and the lower part 122 of the sealing body. The upper part of the sealing body is divided into sealing teeth 124 and the sealing cavity 126. The cooperation between the fixing ring 123 and the fine thread fastens the upper and lower parts of the sealing body.

As shown in Fig. 6, the oil seal group of the present invention includes a body 131 and a Babbitt alloy layer 132. The sealing surface of the body is zigzag or concave-convex pitted surface, which is located on the inner wall of the sealing ring and has a certain taper. During production, the oil seal group body is first provided with a zigzag or concave-convex sealing surface, then Babbitt alloy is poured on the sealing surface, and finally the inner and outer rings are assembled into one body to form the oil seal group.

Below we will further illustrate the parameters of the two-way intake multistage centrifugal compressor of the present invention through specific examples.

Embodiment 1 Two-way intake three-stage centrifugal compressor with backward curved blades

This embodiment is a three-stage centrifugal compressor, the impellers are divided into two groups, one group has one impeller; the other group has two impellers, and the two groups of impellers are installed on the main shaft in opposite directions. The impeller adopts an open impeller, and its blades adopt a backward curved structure, and the deflection between the front and rear impeller blades is 5 degrees; the vaneless diffuser is arranged on the low-pressure stage side, while the vane diffuser is arranged on the high-pressure stage side. The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute with ribs on both sides of the outlet partition, the inlet and outlet volute with ribs on both sides of the outlet partition, the structure of the gas seal and the oil seal group are all the same as before mentioned, no further explanation is required.

Embodiment 2 Two-way intake five-stage centrifugal compressor with backward curved blades

This embodiment is a five-stage centrifugal compressor, the impellers are divided into two groups, one group has two impellers; the other group has three impellers, and the two groups of impellers are reversely installed on the main shaft. The impeller adopts a semi-open impeller, and its blades adopt a backward curved structure, and the blades of the front and rear impellers are deflected by 15 degrees; the bladeless diffuser is configured on the low-pressure stage side, and each bladeless diffuser is equipped with a bladed diffuser . The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the structure of the gas seal body and the oil seal group are as before. , no further explanation is required.

Embodiment 3 Two-way intake four-stage centrifugal compressor with backward curved blades

This embodiment is a four-stage centrifugal compressor, the impellers are divided into two groups, each group has two impellers, and the two groups of impellers are reversely installed on the main shaft. The impeller adopts a closed impeller, and its blades adopt a backward curved structure, and the blades of the front and rear impellers are deflected by 10 degrees; the bladeless diffuser is configured on the low-pressure stage side, and each bladeless diffuser is equipped with a bladed diffuser. The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the structure of the gas seal body and the oil seal group are as before. , no further explanation is required.

Embodiment 4 Two-way intake three-stage centrifugal compressor with forward curved blades

This embodiment is a three-stage centrifugal compressor, the impellers are divided into two groups, one group has one impeller; the other group has two impellers, and the two groups of impellers are installed on the main shaft in opposite directions. The impeller adopts an open impeller, and its blades adopt a forward-curved structure, and the front and rear impeller blades are deflected by 5 degrees; the bladeless diffuser is arranged on the low-pressure stage side, and the vane diffuser is arranged on the high-pressure stage side. The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute with ribs on both sides of the outlet partition, the inlet and outlet volute with ribs on both sides of the outlet partition, the structure of the gas seal and the oil seal group are all the same as before mentioned, no further explanation is required.

Embodiment 5 Two-way intake five-stage centrifugal compressor with forward curved blades

This embodiment is a five-stage centrifugal compressor, the impellers are divided into two groups, one group has two impellers; the other group has three impellers, and the two groups of impellers are reversely installed on the main shaft. The impeller adopts a semi-open impeller, and its blades adopt a forward-curved structure, and the blades of the front and rear impellers are deflected by 15 degrees; the bladeless diffuser is configured on the low-pressure stage side, and each bladeless diffuser is equipped with a bladed diffuser . The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the structure of the gas seal body and the oil seal group are as before. , no further explanation is required.

Embodiment 6 Two-way intake four-stage centrifugal compressor with forward curved blades

This embodiment is a four-stage centrifugal compressor, the impellers are divided into two groups, each group has two impellers, and the two groups of impellers are reversely installed on the main shaft. The impeller adopts a closed impeller, and its blades adopt a forward-curved structure, and the blades of the front and rear impellers are deflected by 10 degrees; the bladeless diffuser is configured on the low-pressure stage side, and each bladeless diffuser is equipped with a bladed diffuser. The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the structure of the gas seal body and the oil seal group are as before. , no further explanation is required.

Embodiment 7 Two-way intake six-stage centrifugal compressor with radial blades

This embodiment is a six-stage centrifugal compressor, the impellers are divided into two groups, each group has three impellers, and the two groups of impellers are reversely installed on the main shaft. The impeller adopts an open impeller, and its blades adopt a radial structure, and the deflection between the front and rear impeller blades is 5 degrees; the vaneless diffuser is arranged on the low-pressure stage side, and the vane diffuser is arranged on the high-pressure stage side. The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute with ribs on both sides of the outlet partition, the inlet and outlet volute with ribs on both sides of the outlet partition, the structure of the gas seal and the oil seal group are all the same as before mentioned, no further explanation is required.

Embodiment 8 Two-way intake five-stage centrifugal compressor with radial blades

This embodiment is a five-stage centrifugal compressor. The impellers are divided into two groups, one with two impellers and the other with three impellers. The two groups of impellers are installed on the main shaft in opposite directions. The impeller adopts a semi-open impeller, and its blades adopt a radial structure, and the blades of the front and rear impellers are deflected by 15 degrees; the bladeless diffuser is configured on the low-pressure stage side, and each bladeless diffuser is equipped with a bladed diffuser . The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the structure of the gas seal body and the oil seal group are as before. , no further explanation is required.

Embodiment 9 Two-way intake four-stage centrifugal compressor with radial blades

This embodiment is a four-stage centrifugal compressor, the impellers are divided into two groups, each group has two impellers, and the two groups of impellers are reversely installed on the main shaft. The impeller adopts a closed impeller, and its blades adopt a radial structure, and the blades of the front and rear impellers are deflected by 10 degrees; the bladeless diffuser is configured on the low-pressure stage side, and each bladeless diffuser is equipped with a bladed diffuser. The rest of the inlet port with adjustable guide vane angle, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the inlet and outlet volute chambers with reinforcing ribs on both sides of the outlet partition, the structure of the gas seal body and the oil seal group are as before. stated without further explanation

Above-mentioned each embodiment is only the design scheme that proposes according to the different conditions of use of different users, these design schemes after signing corresponding non-disclosure agreement with the user, the special case that the prototype is provided to the user for trial and obtains comparatively satisfactory effect, therefore can also enumerate Come up with more examples.

The utility model focuses on the influence of the circulation on the outlet airflow velocity under the condition of limited blades with a bidirectional air intake structure, and on this basis, the combination of the diffuser, the inlet port, the inlet and outlet volute and the oil seal group The structure has been improved accordingly, and the design of the two-way inlet and outlet airflow channels has been adopted, finally forming this brand new design scheme. It is characterized in that it is suitable for various fluid media and airflows of different pressures, so it can be applied to various professions and projects, and is welcomed by various types of enterprises, and has achieved good social and economic benefits.

Claims (8)

1. a bidirection air intake multistage centrifugal compressor, it mainly includes: main shaft, impeller, spacer, thrust disc, Balance disc, diaphragm coupling, Diffuser, return channel, bend, import and export volute casing, sealing, bearing pack parts, housing etc., is characterized in that:

(1) adopt multiple tandem impeller, between adjacent two impellers, the blade of a rear impeller arranges the angle certain relative to the blade deflection of previous impeller;

(2) Diffuser adopt vaneless diffuser with the combination of vane diffuser, vaneless diffuser at front and vane diffuser rear;

(3) intake duct of the stator adjustable angle be made up of inner ring, outer shroud, side plate and stator is adopted;

(4) the import and export volute casing of dividing plate both sides band stiffening rib is adopted;

(5) air sealing of the overall assembling of split sealing;

(6) adopt seal ring inwall with the oil seal group structure on the inclined-plane of certain taper;

(7) intake method adopts two inlet charge structures;

(8) mode of giving vent to anger also adopts two air outlet air outlet structures.

2. by bidirection air intake multistage centrifugal compressor according to claim 1, it is characterized in that between said two impellers adjacent at impeller, the blade of a rear impeller arranges the angle certain relative to the blade deflection of previous impeller; For backward leaning vane be: 5 ~ 15 degree; For forward curved vane be: 5 ~ 15 degree; It is 5 ~ 30 degree for radial blade.

3. by bidirection air intake multistage centrifugal compressor according to claim 1, it is characterized in that the intake duct of said stator adjustable angle, be separately equipped with guide positioning pin, the locating stud changing stator angle and stator rotating center pin.

4. by bidirection air intake multistage centrifugal compressor according to claim 1, the import and export volute casing that it is characterized in that said employing outlet partition plate both sides band stiffening rib is spliced by upper and lower two-part, dividing plate biside plate face is respectively equipped with helical line type volute casing runner, between biside plate face, is distributed with reinforcement gusset; Split between dividing plate top and the bottom also do not have ring stiffener.

5. by bidirection air intake multistage centrifugal compressor according to claim 1, it is characterized in that the overall assembling of said split sealing, comprise upper-lower seal body, seal body is designed with for it sealing tooth and Seal cage, and with seal ring by with closely cooperating of the fine thread on lower seal upper-lower seal body being tightened up.

6. by bidirection air intake multistage centrifugal compressor according to claim 1, it is characterized in that the oil seal group structure of said seal ring inwall with the inclined-plane of certain taper, its sealing surface is be positioned at seal ring inwall and with the inclined-plane of tapering, there are flexuose or concavo-convex decorative pattern on the surface, it is provided with babbit layer.

7., by bidirection air intake multistage centrifugal compressor according to claim 1, it is characterized in that said intake method adopts bidirection air intake mouth air intake structure, the lower housing of its compressor is with four gas ports, and namely two is one group of compression completing a kind of fluid; And another group gas port also can complete a kind of compression of fluid simultaneously, two kinds of fluids are contained among two containers respectively.

8., by the bidirection air intake multistage centrifugal compressor described in claim 1 or 7, it is characterized in that said two air outlets are arranged on the outer end of compressor; And two air outlets are arranged on the intermediate portion of compressor.