WO2024051099A1

WO2024051099A1 - Suspension centrifugal compressor and air conditioner system

Info

Publication number: WO2024051099A1
Application number: PCT/CN2023/077577
Authority: WO
Inventors: 宋斌; 吴刚
Original assignee: 深圳市英维克科技股份有限公司
Priority date: 2022-09-07
Filing date: 2023-02-22
Publication date: 2024-03-14
Also published as: CN115596686A

Abstract

A suspension centrifugal compressor, comprising a main shaft (1), an impeller device (2) fixedly mounted on the main shaft (1), and a radial gas bearing (5) and an axial gas bearing (6) which are sleeved on the main shaft (1), wherein the main shaft (1) extends up and down; and when the impeller device (2) rotates, an axial thrust acting on the main shaft (1) is upward. Because the main shaft (1) extends up and down, the axial upward thrust can achieve the effect of overcoming the gravity of the main shaft (1), so that less gravity of the main shaft (1) is borne by the axial bearing, thereby effectively reducing the working pressure of the axial bearing, such as the axial gas bearing (6). In an operating state, the working pressure of the axial gas bearing (6) can be effectively reduced, so that an air supply amount can be reduced, so as to achieve the effect of reducing energy consumption, and the efficiency of the whole machine is increased; in addition, the radial bearing does not need to bear gravity, so the working pressure can also be reduced, and vibration is minimized. Further disclosed is an air conditioner system comprising the suspension centrifugal compressor.

Description

Suspended centrifugal compressor and air conditioning system

This application claims priority to the Chinese patent application filed with the China Patent Office on September 7, 2022, with the application number 202211099064.2 and the invention name "Suspension Centrifugal Compressor and Air Conditioning System", the entire content of which is incorporated into this application by reference. .

Technical field

The present invention relates to the technical field of compressors, and more specifically, to a suspended centrifugal compressor and an air conditioning system including the above-mentioned suspended centrifugal compressor.

Background technique

Current air suspension centrifugal compressors are generally placed horizontally, and the gas bearing is sleeved on the main shaft. During operation, the radial force on the main shaft needs to overcome the weight of the gas bearing itself, and the source of this force is for the gas static pressure bearing. It may be the introduction of external air supply or internal compressor exhaust, which is a compressed air wedge for gas dynamic pressure bearings; the axial force may be offset by the introduction of the support of the gas bearing, but the radial force is affected by the spindle's own gravity. It cannot be offset; when the gas supply volume is insufficient, it will cause the problem of insufficient reliability. When the gas supply volume is sufficient, the loss increases and the overall machine efficiency is reduced.

To sum up, how to effectively solve the problem of excessive bearing pressure on the spindle is an urgent problem that those skilled in the art currently need to solve.

Contents of the invention

In view of this, the present invention provides a suspended centrifugal compressor, which can effectively solve the problem of excessive bearing pressure on the main shaft. The present invention provides an air conditioning system including the above-mentioned suspended centrifugal compressor.

The present invention provides the following technical solutions:

A suspended centrifugal compressor includes a main shaft, an impeller device fixedly installed on the main shaft, and a radial gas bearing and an axial gas bearing sleeved on the main shaft. The main shaft extends up and down, and the impeller device rotates. When the axial thrust acting on the spindle is upward.

When using the above-mentioned suspended centrifugal compressor, when the impeller device starts to rotate to compress the air When using air or other gases, the impeller of the impeller device will form an axial upward thrust due to the air pressure, and because the main shaft extends up and down, the axial upward thrust can overcome the gravity of the main shaft, so that the gravity of the main shaft Less axial bearing burden effectively reduces the working pressure of the axial bearing. For example, when the axial gas bearing is in operation, the working pressure of the axial gas bearing can be effectively reduced, thereby reducing the air supply. The amount can reduce energy consumption and improve the efficiency of the whole machine. At the same time, the radial bearing no longer needs to bear gravity, so it can also reduce the working pressure and minimize vibration. To sum up, the suspended centrifugal compressor can effectively solve the problem of excessive bearing pressure on the main shaft.

Preferably, the impeller device has a plurality of impellers, and when each impeller of the impeller device rotates, the total axial thrust acting on the main shaft is upward.

Preferably, when each impeller of the impeller device rotates, the axial thrust acting on the main shaft is all upward.

Preferably, each impeller of the impeller device has an axial air inlet and a radial air outlet.

Preferably, the impellers located at both ends of the main shaft are arranged oppositely or away from each other.

Preferably, each impeller of the impeller device is axially drawn downward.

Preferably, each impeller of the impeller device is disposed at one end of the main shaft or at both ends of the main shaft respectively.

Preferably, the main shaft is arranged vertically.

In order to achieve the above second object, the present invention also provides an air conditioning system. The air conditioning system includes any of the above suspended centrifugal compressors, including an evaporator and a condenser. The suspended centrifugal compressor is connected to the evaporator. between the condenser. Since the above-mentioned suspended centrifugal compressor has the above-mentioned technical effects, the air-conditioning system equipped with the suspended centrifugal compressor should also have corresponding technical effects.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only are some embodiments of the present invention. For those of ordinary skill in the art Generally speaking, other drawings can also be obtained based on these drawings without exerting creative work.

Figure 1 is a schematic structural diagram of a suspended centrifugal compressor provided by an embodiment of the present invention;

Figure 2 is a schematic structural diagram of the impellers arranged in opposite directions according to the embodiment of the present invention;

Figure 3 is a schematic structural diagram of impellers arranged relative to each other according to an embodiment of the present invention;

Figure 4 is a schematic structural diagram of impellers arranged in the same direction according to an embodiment of the present invention;

Figure 5 is a schematic structural diagram of the impeller provided on the same side according to the embodiment of the present invention.

The following are marked in the attached drawing:
Main shaft 1, impeller device 2, volute 3, stator 4, radial gas bearing 5, axial gas bearing 6,
Impeller 21.

Detailed ways

The embodiment of the present invention discloses a suspended centrifugal compressor to effectively solve the problem of excessive bearing pressure on the main shaft.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Please refer to Figures 1-5. Figure 1 is a schematic structural diagram of a suspended centrifugal compressor provided by an embodiment of the present invention; Figure 2 is a schematic structural diagram of an impeller phase deviation arrangement provided by an embodiment of the present invention; Figure 3 is a schematic structural diagram of a suspended centrifugal compressor provided by an embodiment of the present invention. A schematic structural diagram of impellers arranged oppositely; Figure 4 is a schematic structural diagram of impellers arranged in the same direction according to an embodiment of the present invention; Figure 5 is a schematic structural diagram of impellers arranged on the same side according to an embodiment of the present invention.

In some embodiments, as shown in Figure 1, a suspension centrifugal compressor is provided, including at least one, more, or even all of the following structures: main shaft 1, impeller device 2, radial gas bearing 5 and Of course, the axial gas bearing 6 may also include some other structures, such as a stator 4, a volute 3, etc. For example, the compressor can include a motor part, a pneumatic part, and a mechanical part. The motor part may include, for example, a stator 4, a coil, and a rotor. The pneumatic part may include an impeller 21, a volute 3, Main shaft 1 and bearings. Main shaft 1 is a moving part connecting the impeller 21 and the motor rotor; the bearing includes a radial support part and an axial support part, that is, the above-mentioned radial gas bearing 5 and axial gas bearing 6. For main shaft 1 and its The associated impeller 21 and the rotor are supported; the volute 3 is a pressure chamber structure with an inlet and an outlet, which can collect the gas generated in the impeller 21 and make it flow to the exhaust port. The mechanical part is related connection and sealing structures. It should be noted that the compressor can be a combination of some of the above structures, or even a combination of all structures. Specifically, it can be set as needed.

The impeller device 2 is fixedly installed on the main shaft 1, and the impeller device 2 may include one or more impellers 21, so that when the main shaft 1 rotates, it can drive the impellers 21 thereon to rotate. The rotation of the main shaft 1 can generally be driven by the coil in the stator 4, or can also be driven by other structures. The impeller 21 can be integrally formed with the main shaft 1, or can be detachably fixedly connected. For example, the impeller 21 is sleeved on the main shaft 1, and is keyed to each other, and is locked by a nut in the upper direction of the shaft, that is, the impeller is axially oriented in one direction. One side can be against the shoulder of the main shaft 1, and the other end can be against the nut threaded on the main shaft. After the nut is removed, the impeller 21 can be detached from the main shaft 1. Of course, the connection relationship between the impeller 21 and the main shaft 1 can also refer to the existing technology.

The main shaft 1 is provided with a radial gas bearing 5 and an axial gas bearing 6 for radial support through the radial gas bearing 5 and axial support through the axial gas bearing 6 therein. Among them, the radial gas bearing 5 and the axial gas bearing 6 can respectively choose dynamic pressure gas bearings and static pressure gas bearings according to needs. Of course, in some other embodiments, the spindle 1 may also be provided with ball bearings, so as to serve as radial bearings and axial bearings respectively.

The spindle 1 is extended up and down, usually vertically. Of course, it can also be tilted, such as tilted upward. Specifically, it can be set as needed. And when the impeller device 2 rotates, the axial thrust acting on the main shaft 1 is upward, so as to overcome the gravity of the main shaft 1 . It should be noted that when the main shaft 1 is arranged vertically, then the axial thrust acting on the main shaft 1 when the impeller device 2 rotates is upward, and it is vertically upward; and if the main shaft 1 is arranged tilted, then the axial thrust is tilted upward, If it is tilted upward, because there is a vertical upward component in the vertical direction, it can also overcome part of the gravity of the spindle 1. In order to better overcome the gravity of the spindle 1, it is preferred that the spindle 1 is arranged vertically.

It should be noted that when the impeller device 2 rotates, the impeller 21 will receive an axial thrust, and this radial thrust will be transmitted to the main shaft 1. Therefore, the setting state of the impeller 21 can be adjusted to effectively The thrust direction of the impeller 21 acting on the main shaft 1 is controlled effectively, that is, the thrust force exerted on the main shaft 1 is controlled upward in the axial direction. It should be noted that if the force exerted by the whole machine on the bottom surface does not change, the wind pressure acting on the impeller 21 can push the shell or the base part of the whole machine in the opposite direction to maintain the force balance.

It should also be noted that the axial thrust formed by the impeller 21 mainly has the following two reasons but is not limited to the following two reasons:

One of the reasons is: due to internal gas leakage, a pressure difference occurs on both sides of the impeller 21 wheel cover and wheel back; and the pressure is F=P*S; P represents the gas pressure, and S represents the action area along the axis or Axial projected area; the pressure on the wheel cover side is the internal leakage generated between exhaust and suction, that is, the pressure difference between the outlet and inlet of impeller 21; that is, as shown in Figure 2, △F = Fa wheel back - Wheel cover; Wheel cover = Pa*Sa, where "*" represents the product, and "=" represents the equal sign; Pa is the pressure between the outlet of the impeller 21 and the inlet of the impeller 21; Sa is the pressure of the wheel cover in the axial direction Component; Wheel back = Pc*Sc; Pc is the pressure between the outlet of impeller 21 and the inner cavity of the motor; Sc is the cross-sectional area of the wheel back perpendicular to the main axis 1; the size of the wheel back and the wheel cover are affected by the pressure and cross-section The size is related to the leakage caused by the matching gap, the operating speed or pressure ratio and the designed cross-sectional size, etc., and depends on the specific situation. Therefore, the corresponding wheel back or wheel cover can be adjusted according to the up and down position relationship between the wheel cover and wheel back, so that the combined force is axially upward.

Another reason: according to the concept of gas dynamics, for example, the air inlet direction and/or the air outlet square of the impeller 21 is axial. If the air inlet direction is axial, it can be axially upward or axially downward, and the air intake is axially upward, the impeller 21 can form a downward axial thrust, and the axial air intake is downward, the impeller 21 Can form upward axial thrust. If the air outlet direction is axial, it can be axially upward or axially downward. If the air outlet is axially upward, the impeller 21 can form a downward axial thrust. If the air outlet is axially downward, the impeller 21 can form a downward axial thrust. Downward axial thrust. In order to better achieve the above effect, for example, the impeller 21 can be made to intake air axially downward and exhaust air axially downward, and refer to the helicopter propeller design principle to achieve the above effect, thereby better overcoming the above problems. . Of course, as shown in Figures 1-5, each impeller 21 of the impeller device 2 can be used for axial air inlet and radial air outlet.

The above two reasons can be adjusted accordingly by the internal structure to change the axial thrust direction to the upward direction. It should be noted that one or more parameters or structures can be selected for improvement, so that after integration, the impeller device The axial thrust of the impeller 21 of 2 on the main shaft 1 is upward. In fact In the design, the axial force direction of the current impeller 21 can be changed. If the axial direction is downward, the axial force direction can be changed based on the above reasons, such as changing the air inlet and outlet direction, changing the size of the wheel cover and wheel back. , and can even further change the axial force.

In some embodiments, when using the above-mentioned suspended centrifugal compressor, when the impeller device 2 starts to rotate to compress air, the impeller 21 of the impeller device 2 will form an axial upward thrust due to the air pressure, and because The main shaft 1 extends up and down, so the axial upward thrust can overcome the gravity of the main shaft 1, so that the axial bearings bear less of the gravity of the main shaft 1, effectively reducing the working pressure of the axial bearings, such as The gas bearing 6, when in operation, can effectively reduce the working pressure of the axial gas bearing 6, thereby reducing the air supply volume, thereby reducing energy consumption and improving the overall machine efficiency. At the same time, the radial bearing There is no need to bear gravity, so the working pressure can also be reduced and vibration can be minimized. To sum up, the suspended centrifugal compressor can effectively solve the problem of excessive bearing pressure on the main shaft 1.

In some embodiments, as shown in Figures 1-5, the impeller device 2 can have multiple impellers 21. In this case, only the axial direction acting on the main shaft 1 when each impeller 21 of the impeller device 2 rotates is required. The total thrust is upward, and preferably the sum of the total axial thrust acting on the main shaft 1 when each impeller 21 of the impeller device 2 rotates is close to the gravity of the main shaft 1 . That is, the vertical component forces of each impeller 21 acting on the main shaft 1 are respectively: F1, F2..., Fn, and at least part of the direction is upward. Then F1+...+Fn+G=0, where G is the gravity and the direction is downward, n is the number of impellers 21 on the same main shaft 1, n≥1. That is, the axial thrust acting on the main shaft 1 when a part of the impeller 21 of the impeller device 2 rotates can be made downward, and the axial thrust acting on the main shaft 1 when the other part of the impeller 21 of the impeller device 2 rotates can be made is upward, but the sum of the two forms an upward thrust, and the magnitude is preferably close to its gravity.

It should be noted:

For a one-stage compression system: there can be only one impeller 21. When the impeller 21 back pressure is greater than the wheel cover pressure, the force direction is from the wheel back to the wheel cover. At this time, the pressure difference is △F1; or, when the impeller 21 When the wheel back pressure is less than the wheel cover pressure, the force direction is from the wheel cover to the wheel back; at this time, the pressure difference is -△F1; it is always required that the force direction of the pressure difference (△F1 or -△F1) should be in the direction of gravity G On the contrary; to offset part of the influence of gravity.

For a multi-stage compression system, that is, with more than two impellers 21, the impellers 21 can be opposed (that is, the two impellers 21 are installed in opposite directions) or in the same direction; or a mixed method of partly in the same direction and partly in opposite directions; at least one impeller 21 The direction of the axial pressure is opposite to the direction of gravity, so that the direction of the resultant force is opposite to the direction of gravity; it can also be that one or more impellers 21 are opposite to the direction of gravity, and the remaining impellers 21 are in the same direction as the gravity. The purpose is to minimize the axial component of the resultant force of the impeller 21 pressure and the main shaft 1 gravity. When there are multi-stage impellers 21, in at least one set of two-stage impellers 21, the higher-stage impeller 21 and the lower-stage impeller 21 can be made smaller in geometric size. Prioritize the design within the range of 50% ± 20% of the load condition, and consider the effect of minimizing or canceling each other out between the thrust and gravity of the impeller 21; in order to minimize the axial support force under common operating conditions and reduce the loss under common operating conditions. .

Among them, the impeller 21 of the higher stage and the impeller 21 of the lower stage are smaller in geometric size. Specifically, it can be calculated according to: Q _m =Q _v *ρ; where Q _m is the mass flow rate (the compression process remains unchanged), and Q _v is the volume flow rate, ρ is the gas density; Q _v =V*S; V is the gas linear velocity, S is the flow cross-sectional area (or outlet cross-section); V=W*R; W=2πf; W is the gas angular velocity, R is the impeller radius; f is the rotation frequency.

The above expression can also be organized into one expression; that is, Q _m =2πf*R*S*ρ;

Under the condition that the mass flow Q _m in the system is basically unchanged, after the lower-level impeller is compressed, the volume of the compressed gas decreases and the density increases; corresponding to the coaxial and same rotation speed, then f does not change, that is, W does not change, V decreases or S decreases, and the decrease of V means that the radius of the impeller decreases; usually the R and outlet cross-section S of the impeller with a higher level are reduced and adjusted at the same time; otherwise, when the same size is compressed with a higher level, it is easy to bring about large diameter and Under large cross-sections, the internal fluid is prone to eddy current losses and other losses, resulting in reduced efficiency and increased costs.

In some embodiments, when each impeller 21 of the impeller device 2 rotates, the axial thrust acting on the main shaft 1 is all upward, which effectively expands the total thrust to better ensure that the total thrust is close to the main shaft 1 The magnitude of gravity.

In some embodiments, as shown in Figures 1-3, each impeller 21 of the impeller device 2 is a shaft. To the inlet and radial outlet. At this time, the impellers 21 at both ends of the main shaft 1 can be arranged oppositely or away from each other, that is, the impellers 21 at both ends of the main shaft 1 have opposite axial air inlet directions. in

The relative arrangement is, as shown in Figure 3, the air inlet direction of the lower end impeller 21 is axially downward, and the air inlet direction of the upper end impeller 21 is axially upward; and the opposite arrangement is, as shown in Figure 1-2, the air inlet direction of the lower end impeller 21 The axial direction is upward, while the air inlet direction of the impeller 21 at the lower end is axially downward.

In some embodiments, as shown in FIGS. 4-5 , each impeller 21 of the impeller device 2 can be configured to inlet air axially downward. Each impeller 21 of the impeller device 2 is disposed at one end of the main shaft 1 or at both ends of the main shaft 1 respectively. As shown in Figure 4, each impeller 21 of the impeller device 2 is respectively disposed at both ends of the main shaft 1. As shown in Figure 5, each impeller 21 of the impeller device 2 is disposed at one end of the main shaft 1. .

In some embodiments, preferably wherein the spindle 1 is arranged vertically. The radial force is set along the horizontal direction; the source of the radial force can be an external air supply or an internal self-formed air wedge.

Based on the suspended centrifugal compressor provided in the above embodiments, the present invention also provides an air conditioning system. The air conditioning system includes any one of the suspended centrifugal compressors in the above embodiments, and further includes an evaporator and a condenser. The suspended centrifugal compressor The machine is connected between the evaporator and the condenser. Since the air conditioning system adopts the suspended centrifugal compressor in the above embodiment, please refer to the above embodiment for the beneficial effects of the air conditioning system.

Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on its differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other.

The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be practiced in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

A suspended centrifugal compressor includes a main shaft, an impeller device fixedly installed on the main shaft, and a radial gas bearing and an axial gas bearing sleeved on the main shaft. It is characterized in that the main shaft extends up and down, so When the impeller device rotates, the axial thrust acting on the main shaft is upward.
The suspension centrifugal compressor according to claim 1, wherein the impeller device has a plurality of impellers, and when each impeller of the impeller device rotates, the total axial thrust acting on the main shaft is upward.
The suspension centrifugal compressor according to claim 2, characterized in that when each impeller of the impeller device rotates, the axial thrust acting on the main shaft is all upward.
The suspension centrifugal compressor according to claim 3, characterized in that each impeller of the impeller device has an axial air inlet and a radial air outlet.
The suspension centrifugal compressor according to claim 4, characterized in that the impellers located at both ends of the main shaft are arranged oppositely or away from each other.
The suspension centrifugal compressor according to claim 4, characterized in that each impeller of the impeller device is axially drawn downward.
The suspension centrifugal compressor according to claim 6, wherein each impeller of the impeller device is disposed at one end of the main shaft or at both ends of the main shaft.
The suspension centrifugal compressor according to any one of claims 1 to 7, characterized in that the main shaft is arranged vertically.
An air conditioning system, including an evaporator and a condenser, characterized in that it also includes a suspended centrifugal compressor according to any one of claims 1 to 8, said suspended centrifugal compressor being connected between said evaporator and said between condensers.