Multi-stage compressor and air-conditioning system

Abstract

The present invention belongs to the technical field of air-conditioning compressors, and particularly relates to a multi-stage compressor and an air-conditioning system. In the multi-stage compressor of the present invention, a low-pressure stage compression mechanism and a high-pressure stage compression mechanism are provided; the low-pressure stage compression mechanism adopts a scroll compression mechanism, including a low-pressure stage pressure control mechanism, which can control the compression ratio of the low-pressure stage compression mechanism and the high-pressure stage compression mechanism of the compressor; the high-pressure stage compression mechanism adopts a rotor compression mechanism, including a high-pressure stage pressure control mechanism, which can control the exhaust of the high-pressure stage compression mechanism to be communicated with the exhaust of the low-pressure stage compression mechanism, so that the multi-stage compressor has a first working state in which only the low-pressure stage compression mechanism participates in the compression work and a second working state in which the low-pressure stage compression mechanism and the high-pressure stage compression mechanism jointly participate in the compression work; the technical solution of the present invention solves the problem that the overall energy efficiency of the compressor needs to be improved due to under-compression of the first-stage compression mechanism in the existing multi-stage compressor technology in the prior art.

Description

Technical Field

[0001] The multi-stage compressor and air-conditioning system of the present invention relate to the technical field of air-conditioning compressors, and particularly to a multi-stage compressor and an air-conditioning system using the multi-stage compressor. Background Art

[0002] Previously, a variety of multi-stage compressors applicable to air-conditioning systems have been disclosed. Japanese Patent Application Laid-Open No. 5-87074 and Japanese Patent No. 4875484 proposed a two-stage compressor of a low-pressure-stage rotary compressor and a high-pressure-stage scroll compressor.

[0003] Japanese Patent Application Laid-Open No. 2000-54975 and Japanese Patent Application Laid-Open No. 2006-152839 both proposed to use an economizer with gas injection to achieve high efficiency and high capacity of two-stage compression.

[0004] Patent CN104074763A discloses a bipolar enthalpy-increasing rotary compressor, which applies a variable capacity control technology to the two-stage enthalpy-increasing rotary compressor.

[0005] Patent CN105402124A discloses a multi-stage compressor. The low-pressure stage is a two-rotor compressor structure, the high-pressure stage is a scroll compressor structure, and the high-pressure side has a capacity control mechanism.

[0006] From the above patents, it can be seen that for the disclosed multi-stage compressor structures, the low-pressure stage is a rotary compressor structure, the high-pressure stage is a rotary compressor or a scroll compressor structure, and there is no exhaust control structure on the low-pressure stage compression structure. Compared with rotary compressors, existing scroll compressors have a higher energy efficiency level. When only operating in single-stage compression, considering the energy efficiency level, the scroll compressor structure should be given priority. At the same time, when the compressor operates under high-pressure ratio conditions and ultra-high-pressure ratio conditions, that is, under low-temperature heating conditions and ultra-low-temperature heating conditions, the operating efficiency of the compressor is low. At this time, the compression capacity of the low-pressure stage compressor in the multi-stage compressor is relatively low, the compression ratio increase is small, and the high-pressure stage compressor has been in an under-compressed working state, so the overall energy efficiency level is low. In the case of intermediate compression ratio conditions, that is, under normal refrigeration conditions, there is also a situation where the high-pressure stage compressor is under-compressed. In the case of extremely low-pressure ratio conditions, that is, under low-temperature refrigeration conditions, there may be a situation where all stages of the multi-stage compressor are over-compressed.

[0007] Therefore, controlling the compression ratios of the various stages of the multi-stage compression structure in a multi-stage compressor can greatly improve the operating efficiency of the compressor and the energy-saving situation of the air-conditioning system.

[0008] In view of the problems existing in the above-mentioned prior art, it is very necessary to research and design a new type of multi-stage compressor and air-conditioning system to overcome the problems existing in the prior art. Summary of the Invention

[0009] In view of the technical problem that the overall energy efficiency of the compressor needs to be improved due to under-compression of the first-stage compression mechanism in the existing multi-stage compressor technology proposed according to the above-mentioned prior art, a multi-stage compressor and an air-conditioning system are provided.

[0010] The technical means adopted by the present invention are as follows:

[0011] A multi-stage compressor includes a compressor; the compressor further includes: an intake pipe, an upper cover, a fixed scroll, a moving scroll, an upper support, a rotor, a cylinder block, a middle support, a bracket, a crankshaft, an electric motor, a lower support assembly, an oil pump, an oil sump, and a lower cover; characterized in that:

[0012] Furthermore, a low-pressure stage compression mechanism and a high-pressure stage compression mechanism are also provided inside the compressor to form a multi-stage compressor;

[0013] Furthermore, the low-pressure stage compression mechanism adopts a scroll compression mechanism, including a low-pressure stage pressure control mechanism, which can control the compression ratios of the low-pressure stage compression mechanism and the high-pressure stage compression mechanism of the compressor;

[0014] Furthermore, the high-pressure stage compression mechanism adopts a rotor compression mechanism, including a high-pressure stage pressure control mechanism, which can control the exhaust of the high-pressure stage compression mechanism to be communicated with the exhaust of the low-pressure stage compression mechanism, so that the multi-stage compressor has a first working state in which only the low-pressure stage compression mechanism participates in the compression work and a second working state in which both the low-pressure stage compression mechanism and the high-pressure stage compression mechanism participate in the compression work;

[0015] Furthermore, the multi-stage compressor further includes an exhaust guide pipe; the exhaust guide pipe passes through the fixed scroll, the upper support, the cylinder block, the middle support, and the bracket to connect the upper cover with the motor side. After the low-pressure stage compression mechanism exhausts, the discharged refrigerant and refrigerant oil mist enter the motor and the oil sump from the upper cover through the exhaust guide pipe. The refrigerant passes through the motor and then flows upward through the channel surrounded by the upper support, the cylinder block, the middle support, and the bracket being pressed against the housing to the middle of the upper support, and is sucked into the compression chamber by the high-pressure stage compression mechanism for secondary compression work; the refrigerant oil is denser than the medium-temperature refrigerant and more remains in the motor and the oil sump, realizing motor cooling, oil-gas separation, and reducing the oil discharge amount of the compressor.

[0016] Furthermore, the low-pressure stage compression mechanism includes: a fixed scroll, a moving scroll, an unloading assembly, and a low-pressure stage pressure control mechanism;

[0017] Furthermore, the fixed scroll and the moving scroll are relatively assembled and fitted;

[0018] Furthermore, the fixed scroll is fixedly connected to the upper support inside the compressor housing by bolts and interference fitting;

[0019] Furthermore, the moving scroll is assembled on the top of the crankshaft;

[0020] Further, an intake pipe is provided at the upper part of the fixed scroll. The bottom end of the intake pipe is fixedly installed at the upper part of the fixed scroll and communicates with its internal cavity. The top end passes through the upper cover and is placed outside the compressor.

[0021] Further, an unloading assembly is provided at the upper part of the fixed scroll.

[0022] Further, a low-pressure stage pressure control mechanism is provided at the mouth of the fixed scroll exhaust port of the fixed scroll.

[0023] Further, the low-pressure stage pressure control mechanism includes: slider B, low-pressure stage valve plate and spring; the low-pressure stage valve plate is installed at the mouth of the fixed scroll exhaust port, and slider B is arranged inside it; the spring is installed in the spring groove at the edge of the fixed scroll exhaust port of the fixed scroll and contacts the bottom of slider B.

[0024] Further, a low-pressure stage pressure control pipeline communicating with the outside of the compressor is provided on the low-pressure stage valve plate; by controlling the low-pressure control pressure in the low-pressure stage pressure control pipeline through the system, the floating and falling of slider B are controlled to complete the opening and closing of the fixed scroll exhaust port, and the compression ratio control of the low-pressure stage compression mechanism can be realized.

[0025] Further, the high-pressure stage compression mechanism includes: rotor, cylinder block, middle support, bracket and high-pressure stage pressure control mechanism.

[0026] Further, the rotor is installed on the crankshaft.

[0027] Further, the bracket, middle support and cylinder block are fixedly connected to the upper support by bolts.

[0028] Further, an exhaust cavity is formed between the middle support and the bracket and is discharged through the exhaust pipe.

[0029] Further, a high-pressure stage exhaust check valve is provided on the middle support, and the high-pressure stage exhaust check valve connects the high-pressure stage compression chamber formed by the rotor and the cylinder block and the high-pressure stage exhaust cavity formed by the middle support and the bracket.

[0030] Further, a bracket communication port is provided at the bottom of the bracket, and a high-pressure stage pressure control mechanism is assembled at the mouth of the bracket communication port.

[0031] Further, the high-pressure stage pressure control mechanism includes: high-pressure stage valve plate, slider A; the high-pressure stage valve plate is installed at the mouth of the bracket communication port, and slider A is assembled inside it.

[0032] Furthermore, a high-pressure stage pressure control pipeline communicating with the outside of the compressor housing is provided on the high-pressure stage valve plate; by controlling the high-pressure control pressure in the high-pressure stage pressure control pipeline through the system, the floating and falling of slider A are controlled to complete the closing and opening of the bracket connection port, and further control the closing and connection of the exhaust cavity formed by the middle support and the bracket with the inside of the housing, so as to control whether the high-pressure stage compression mechanism participates in the compression work.

[0033] Furthermore, a low-pressure stage gas supply pipe is provided in the low-pressure stage compression mechanism. The bottom end of the low-pressure stage gas supply pipe communicates with the low-pressure stage compression chamber formed by the fixed scroll and the moving scroll through the fixed scroll, and the top end communicates with the outside of the upper cover.

[0034] Furthermore, a high-pressure stage gas supply pipe is provided in the high-pressure stage compression mechanism. The high-pressure stage gas supply pipe enters from the outside of the compressor housing into the inside and is connected to the high-pressure stage compression chamber formed by the cylinder block and the rotor in the cylinder block.

[0035] Furthermore, a low-pressure stage valve plate exhaust port is provided on the side wall of the low-pressure stage valve plate.

[0036] Furthermore, both the low-pressure stage valve plate exhaust port and the unloading component face the suction pipe. The exhaust temperature of the low-pressure stage compression mechanism and the exhaust temperature of the intermediate unloading are higher than the suction temperature, so that the refrigerant in the suction pipe is heated, avoiding the compressor from sucking liquid refrigerant and compressing it.

[0037] An air-conditioning system using a multi-stage compressor includes a multi-stage compressor; characterized in that: the air-conditioning system further includes: an expansion valve, a solenoid valve, a four-way reversing valve, a condenser, an economizer, an evaporator, a liquid storage tank and a capillary tube.

[0038] Furthermore, the expansion valve is a general term, including multiple single expansion valves which are: expansion valve A, expansion valve B, expansion valve C and expansion valve D.

[0039] Furthermore, the solenoid valve is a general term, including multiple single solenoid valves which are: solenoid valve A, solenoid valve B, solenoid valve C, solenoid valve D, solenoid valve E, solenoid valve F and solenoid valve G.

[0040] Furthermore, the main path output of the economizer is connected to the input end of the evaporator through solenoid valve A and expansion valve A. The output end of the evaporator is connected to the input end of the four-way reversing valve, and is connected to the suction pipe of the multi-stage compressor by the output end of the four-way reversing valve.

[0041] Furthermore, the auxiliary path of the economizer is connected to the high-pressure stage gas supply pipe of the multi-stage compressor through solenoid valve B.

[0042] Further, the economizer bypass branch is connected to the low-pressure stage supplementary air pipe of the multi-stage compressor after being relieved by the gas output from the solenoid valve C and the expansion valve B and the front exhaust bypass of the condenser;

[0043] Further, the front exhaust branch of the condenser is connected to the high-pressure stage pressure control pipeline of the multi-stage compressor through a capillary tube, a solenoid valve D, a liquid storage tank, an expansion valve C, and a solenoid valve E;

[0044] Further, the rear-end branch of the condenser is connected to the low-pressure stage pressure control pipeline of the multi-stage compressor and the input end of the economizer through a solenoid valve G and an expansion valve D.

[0045] Further, the exhaust pipe of the multi-stage compressor is connected to the condenser through a four-way reversing valve.

[0046] The multi-stage compressor and the air-conditioning system adopted by the present invention control the opening or closing of the exhaust of the low-pressure stage compression mechanism through the exhaust pressure in the system, thereby controlling the compression ratio of the low-pressure stage compression mechanism. Then, the opening or closing of the exhaust of the high-pressure stage compression mechanism is controlled through the exhaust pressure in the system, thereby controlling whether the high-pressure stage compression mechanism works. Thus, both compression mechanisms of the compressor can be in a more efficient working state under various compression ratio conditions, and further, the efficiency of the compressor is greatly improved, and the energy-saving effect of the air-conditioning system is more obvious.

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] 1. The multi-stage compressor provided by the present invention can control the exhaust pressure of the first-stage compression and whether the second stage participates in the compression work through the low-pressure stage pressure control mechanism and the high-pressure stage pressure control mechanism, realizing the improvement of energy efficiency under all working conditions;

[0049] 2. The multi-stage compressor provided by the present invention can greatly improve the working conditions of over-compression of the first-stage compression or under-compression of the second-stage compressor, realizing the working ability with a wide operating range of compression ratio from 1.2 to 64 times, and greatly improving the problem of the small operating range of the existing multi-stage compressor;

[0050] 3. The multi-stage compressor provided by the present invention has a simple structure, low design cost, and wide application range. Combined with the system control method provided by the present invention, it can be generally applied to the current air-conditioning units.

[0051] In summary, the technical solution of the present invention solves the problem that the overall energy efficiency of the compressor needs to be improved due to under-compression of the first-stage compression mechanism in the existing multi-stage compressor technology. Description of the Drawings

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0053] Figure 1 Schematic diagram of the multi-stage compressor structure of the present invention;

[0054] Figure 2 Schematic diagram of the low-pressure stage pressure control mechanism in the multi-stage compressor of the present invention;

[0055] Figure 3 Schematic diagram of the high-pressure stage pressure control mechanism in the multi-stage compressor of the present invention;

[0056] Figure 4 Schematic diagram of the refrigeration cycle of the air-conditioning system using the multi-stage compressor of the present invention.

[0057] In the figure: 1, suction pipe; 2, upper cover; 3, fixed scroll; 4, moving scroll; 5, upper support; 6, exhaust guide pipe; 7, rotor; 8, cylinder block; 9, middle support; 10, bracket; 11, crankshaft; 12, motor; 13, lower support assembly; 14, oil pump; 15, oil sump; 16, lower cover; 17, unloading assembly; 18, high-pressure stage pressure control mechanism; 19, high-pressure stage pressure control pipeline; 20, low-pressure stage pressure control mechanism; 21, low-pressure stage pressure control pipeline; 22, low-pressure stage gas supply pipe; 23, high-pressure stage gas supply pipe; 24, exhaust pipe; 25, slider A; 26, bracket communication port; 27, low-pressure stage valve plate; 28, slider B; 29, spring; 30, fixed scroll exhaust port; 31, low-pressure stage valve plate exhaust port; 32, high-pressure stage exhaust check valve; 33, high-pressure stage valve plate exhaust port; 34, high-pressure stage valve plate; 35a, expansion valve A; 35b, expansion valve B; 35c, expansion valve C; 35d, expansion valve D; 36a, solenoid valve A; 36b, solenoid valve B; 36c, solenoid valve C; 36d, solenoid valve D; 36e, solenoid valve E; 36f, solenoid valve F; 36g, solenoid valve G; 37, multi-stage compressor; 38, four-way reversing valve; 39, condenser; 40, economizer; 41, evaporator; 42, liquid storage tank; 43, capillary tube. Detailed implementation manners

[0058] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The following will describe the present invention in detail with reference to the drawings and in combination with the embodiments.

[0059] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, 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. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0060] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0061] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods and devices should be regarded as part of the authorized specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0062] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present invention. The orientation words "inside, outside" refer to inside and outside the contour of each component itself.

[0063] For ease of description, spatial relative terms, such as "above", "over", "on the upper surface", "upper", etc., may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "beneath" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding interpretations of the spatial relative descriptions used herein will be made accordingly.

[0064] In addition, it should be noted that the use of terms such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. Without further statement, the above terms have no special meaning, and thus should not be construed as limiting the protection scope of the present invention.

[0065] As shown in the figure, the present invention provides a multistage compressor, including a low-pressure stage compression mechanism and a high-pressure stage compression mechanism. The low-pressure stage compression mechanism adopts a scroll compression structure, and the high-pressure stage compression mechanism adopts a rotor compression mechanism. Considering that the scroll structure has a higher operating efficiency than the rotor structure, its high-efficiency compression range is 3 - 6 times the compression ratio, while the high-efficiency compression range of the rotor structure is 1.2 - 1.6 times the compression ratio, and the rotor structure has a more obvious operating advantage when operating under ultra-high pressure ratio conditions. Also, since the high-pressure stage compression mechanism of the present invention includes a high-pressure stage pressure control mechanism 18, it can control the exhaust of the high-pressure stage compression mechanism to be communicated with the exhaust of the low-pressure stage compression mechanism, so that the multistage compressor has a first working state in which only the low-pressure stage compression mechanism participates in the compression work and a second working state in which both the low-pressure stage compression mechanism and the high-pressure stage compression mechanism participate in the compression work. When in the second working state, the low-pressure stage pressure control mechanism can effectively control the compression pressure ratio of each compression unit of the multistage compressor, thereby adjusting the overall energy efficiency level of the compressor and realizing the improvement of the overall energy efficiency level of the compressor.

[0066] As Figures 1-3 shown, the multistage compressor includes a compressor; the compressor further includes: an intake pipe 1, an upper cover 2, a fixed scroll 3, a moving scroll 4, an upper support 5, a rotor 7, a cylinder block 8, a middle support 9, a bracket 10, a crankshaft 11, a motor 12, a lower support assembly 13, an oil pump 14, an oil sump 15, and a lower cover 16;

[0067] As Figures 1-3As shown, a low-pressure stage compression mechanism and a high-pressure stage compression mechanism are also provided inside the compressor, constituting a multi-stage compressor 37;

[0068] As Figure 2 shown, the low-pressure stage compression mechanism adopts a scroll compression mechanism, including a low-pressure stage pressure control mechanism 20, which can control the compression ratio of the low-pressure stage compression mechanism and the high-pressure stage compression mechanism of the compressor;

[0069] As Figure 3 shown, the high-pressure stage compression mechanism adopts a rotor compression mechanism, including a high-pressure stage pressure control mechanism 18, which can control the communication between the exhaust of the high-pressure stage compression mechanism and the exhaust of the low-pressure stage compression mechanism, so that the multi-stage compressor has a first working state in which only the low-pressure stage compression mechanism participates in the compression work and a second working state in which both the low-pressure stage compression mechanism and the high-pressure stage compression mechanism participate in the compression work;

[0070] As Figure 1 shown, the multi-stage compressor also includes an exhaust guide pipe 6; the exhaust guide pipe 6 passes through the fixed scroll 3, the upper support 5, the cylinder block 8, the middle support 9, and the bracket 10 to connect the upper cover 2 with the motor 12 side. After the low-pressure stage compression mechanism exhausts, the discharged refrigerant and refrigerant oil mist enter the motor 12 and the oil sump 15 through the exhaust guide pipe from the upper cover 2. After passing through the motor 12, the refrigerant flows upward through the channel formed by being pressed by the upper support 5, the cylinder block 8, the middle support 9, and the bracket 10 and the housing to the middle of the upper support 5, and is sucked into the compression chamber by the high-pressure stage compression mechanism for secondary compression work; the refrigerant oil is denser than the medium-temperature refrigerant and stays more in the motor 12 and the oil sump 15, realizing motor cooling, oil-gas separation, and reducing the oil discharge amount of the compressor.

[0071] As Figure 2 shown, the low-pressure stage compression mechanism includes a fixed scroll 3, a moving scroll 4, an unloading assembly 17, and a low-pressure stage pressure control mechanism 20;

[0072] The described low-pressure stage pressure control mechanism 20 is communicated with the low-pressure stage pressure control pipeline 21. After the low-pressure stage pressure control mechanism 20 is opened, the first-stage exhaust gas generated by the compression of the fixed scroll 3 and the moving scroll 4 enters the upper cover 2 through the fixed scroll exhaust port 30 and the low-pressure stage valve plate exhaust port 31. After the low-pressure stage pressure control mechanism 20 is closed, the fixed scroll 3 and the moving scroll 4 continue to operate the compressor until the low-pressure stage pressure control mechanism 20 is opened for exhaust. The low-pressure stage pressure control mechanism 20 is composed of a slider B28, a low-pressure stage valve plate 27, and a spring 29. The low-pressure stage valve plate 27 is communicated with the low-pressure stage pressure control pipeline 21, and a low-pressure stage valve plate exhaust port 31 is arranged in the low-pressure stage valve plate 27. The low-pressure stage pressure control mechanism 20 is fixed above the fixed scroll exhaust port 30. There is a low-pressure control pressure in the low-pressure stage pressure control pipeline 21 through system control. When the combined force formed by the exhaust pressure of the low-pressure stage compression mechanism and the spring 29 is less than the low-pressure control pressure, the slider B28 drops and closes, the fixed scroll exhaust port 30 closes, and the fixed scroll 3 and the moving scroll 4 continue to operate the compressor. When the combined force formed by the exhaust pressure of the low-pressure stage compression mechanism and the spring 29 is greater than the low-pressure control pressure, the slider B28 floats up and opens, the fixed scroll exhaust port 30 opens and is communicated with the low-pressure stage valve plate exhaust port 31, and the low-pressure stage compression mechanism exhausts into the upper cover 2.

[0073] The controllable pressure ratio of the low-pressure stage compression mechanism enables the compression amount of each stage of compression of the compressor to be adjusted, which can fully avoid the situation of under-compression in the first-stage compression and still under-compression in the second-stage compression. Although in the working conditions of an ultra-large pressure ratio, such as when operating at a pressure ratio of 20 times (i.e., the exhaust pressure is 20 times the suction pressure) or more, the multi-stage compressor structure disclosed in the present invention may still have the situation of under-compression in both the first-stage compressor and the second-stage compression, but providing control over the exhaust pressure of the first-stage compression can effectively improve the degree of under-compression in the second-stage compression, thereby greatly improving the operating efficiency of the compressor.

[0074] As Figure 3 shown, the described high-pressure stage compression mechanism includes a rotor 7, a cylinder block 8, a middle support 9, a bracket 10, and a high-pressure stage pressure control mechanism 18;

[0075] The high-pressure stage pressure control mechanism 18 is communicated with the high-pressure stage pressure control pipeline 19. When the high-pressure stage pressure control mechanism 18 is closed, the second-stage exhaust gas generated by the compression of the rotor 7 and the cylinder block 8 is exhausted through the exhaust cavity formed by the middle support 9 and the bracket 10 via the exhaust pipe 24. When the high-pressure stage pressure control mechanism 18 is opened, the exhaust cavity formed by the middle support 9 and the bracket 10 is communicated with the first-stage exhaust gas, and the high-pressure stage compression mechanism does not perform compression but directly exhausts.

[0076] The high-pressure stage pressure control mechanism 18 consists of a high-pressure stage valve plate 34 and a slider A25. The high-pressure stage valve plate 34 is connected to the high-pressure stage pressure control pipeline 19, and a high-pressure stage valve plate exhaust port 33 is provided in the high-pressure stage valve plate 34. The high-pressure stage pressure control mechanism 18 is fixed below the bracket connection port 26.

[0077] Through system control, there is a high-pressure control pressure in the high-pressure stage pressure control pipeline 19. When the exhaust pressure of the high-pressure stage compression mechanism is less than the high-pressure control pressure, the slider A25 floats up and closes, and the bracket connection port 26 closes. The rotor 7 and the cylinder block 8 continue to perform the compressor work. The gas enters the exhaust cavity formed by the middle support 9 and the bracket 10 through the high-pressure stage exhaust check valve 32 and is discharged through the exhaust pipe. When the high-pressure control pressure is less than the exhaust pressure of the high-pressure stage compression mechanism, the slider A25 drops and opens. The exhaust cavity formed by the middle support 9 and the bracket 10 is communicated with the inside of the housing through the bracket connection port 26 and the high-pressure stage valve plate exhaust port 33, that is, communicated with the first-stage exhaust. The high-pressure stage compression mechanism does not perform compression but directly exhausts.

[0078] When the compressor operates under low pressure ratio conditions, for example, when the compression ratio is less than 3, the high-pressure stage compression mechanism does not perform compression through the high-pressure stage pressure control mechanism 18, which greatly improves the low operating efficiency of the compressor caused by over-compression due to the second-stage compression. At the same time, an unloading component 17 is arranged on the fixed scroll 3 of the low-pressure stage compression mechanism, so that in the first working state where only the low-pressure stage compressor participates in the compression work, the exhaust is advanced further under low pressure ratio conditions, further avoiding over-compression and improving the operating efficiency.

[0079] As Figure 4 shown, an air-conditioning system using a multi-stage compressor includes a multi-stage compressor 37; characterized in that: the air-conditioning system further includes: an expansion valve 35, a solenoid valve 36, a four-way reversing valve 38, a condenser 39, an economizer 40, an evaporator 41, a liquid storage tank 42, and a capillary tube 43;

[0080] The expansion valve 35 is a general term, including multiple single expansion valves, namely: expansion valve A 35a, expansion valve B 35b, expansion valve C 35c, and expansion valve D 35d;

[0081] The solenoid valve 36 is a general term, including multiple single solenoid valves, namely: solenoid valve A 36a, solenoid valve B 36b, solenoid valve C 36c, solenoid valve D 36d, solenoid valve E 36e, solenoid valve F 36f, and solenoid valve G 36g;

[0082] The main path output of the economizer 40 is connected to the input end of the evaporator 41 through the solenoid valve A 36a and the expansion valve A 35a. The output end of the evaporator 41 is connected to the input end of the four-way reversing valve 38, and is connected to the suction pipe 1 of the multi-stage compressor 37 by the output end of the four-way reversing valve 38;

[0083] The auxiliary circuit of the economizer 40 is connected to the high-pressure stage gas supply pipe 23 of the multi-stage compressor 37 through the solenoid valve B36b;

[0084] The branch of the auxiliary circuit of the economizer 40 is connected to the front exhaust auxiliary circuit of the condenser 39 through the solenoid valve C36c and the expansion valve B35b, and after the gas output from the solenoid valve F36f is relieved, it is connected to the low-pressure stage gas supply pipe 22 of the multi-stage compressor 37; the front exhaust auxiliary circuit of the condenser 39 is high-temperature steam, and the branch of the auxiliary circuit of the economizer 40 is high-pressure liquid refrigerant or gas-liquid mixed refrigerant through the solenoid valve 36c and the expansion valve 35b; the high-temperature steam is mixed with the liquid refrigerant or gas-liquid mixed refrigerant, which can improve the air supply reliability of the compressor and further improve the air supply or gas-liquid mixed injection effect.

[0085] The front exhaust branch of the condenser 39 is connected to the high-pressure stage pressure control pipeline 19 of the multi-stage compressor 37 through the capillary 43, the solenoid valve D36d, the liquid storage tank 42, the expansion valve C35c, and the solenoid valve E36e;

[0086] The rear-end branch of the condenser 39 is connected to the low-pressure stage pressure control pipeline 21 of the multi-stage compressor 37 and the input end of the economizer 40 through the solenoid valve G36g and the expansion valve D35d.

[0087] The exhaust pipe 1 of the multi-stage compressor 37 is connected to the condenser 39 through the four-way reversing valve 38;

[0088] Through the mutual cooperation of the solenoid valve 36 and the expansion valve 35, the low-pressure stage pressure control mechanism 20 and the high-pressure stage pressure control mechanism 18 can realize the pressure control functions of opening and closing, thereby improving the operation efficiency of the compressor and even the system.

[0089] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-stage compressor, comprising a compressor; the compressor further comprising: Intake pipe, upper cover, fixed scroll, movable scroll, upper support, rotor, cylinder block, middle support, bracket, crankshaft, motor, lower support assembly, oil pump, oil pool and lower cover; characterized in that: The compressor is also provided with a low-pressure stage compression mechanism and a high-pressure stage compression mechanism, forming a multi-stage compressor; The low-pressure stage compression mechanism adopts a scroll compression mechanism, including a low-pressure stage pressure control mechanism, which can control the compression ratio of the low-pressure stage compression mechanism and the high-pressure stage compression mechanism of the compressor; The high-pressure stage compression mechanism adopts a rotor-type compression mechanism, including a high-pressure stage pressure control mechanism, which can control the high-pressure stage compression mechanism exhaust and the low-pressure stage compression mechanism exhaust to be connected, so that the multi-stage compressor has a first working state in which only the low-pressure stage compression mechanism participates in the compression work and a second working state in which both the low-pressure stage compression mechanism and the high-pressure stage compression mechanism participate in the compression work; The multi-stage compressor also includes an exhaust guide pipe; the exhaust guide pipe passes through the fixed scroll, the upper support, the cylinder body, the middle support, and the bracket to connect the upper cover with the motor side. After the low-pressure compression mechanism is exhausted, the exhausted refrigerant and the refrigeration oil mist enter the motor and the oil pool from the upper cover through the exhaust guide pipe. After passing through the motor, the refrigerant flows upward to the middle part of the upper support through the channel surrounded by the upper support, the cylinder body, the middle support, and the bracket after being pressed together with the shell, and is sucked into the compression chamber by the high-pressure compression mechanism for secondary compression. The refrigeration oil has a higher density than the medium-temperature refrigerant, and more of it is retained in the motor and the oil pool, so as to achieve motor cooling, oil and gas separation, and reduce the oil discharge of the compressor; The bottom of the bracket is provided with a bracket communication port, and the mouth of the bracket communication port is equipped with a high-pressure level pressure control mechanism; The high-pressure stage pressure control mechanism comprises: a high-pressure stage valve plate; The high-pressure stage valve plate is provided with a high-pressure stage pressure control pipeline connected to the outside of the compressor housing, and the high-pressure stage valve plate is provided with a high-pressure stage valve plate exhaust port, and there is a high-pressure control pressure in the high-pressure stage pressure control pipeline; when the exhaust pressure of the high-pressure stage compression mechanism is less than the high-pressure control pressure, the bracket connection port is closed, the rotor and the cylinder body continue to work as a compressor, and the gas enters the exhaust chamber formed by the middle support and the bracket through the high-pressure stage exhaust one-way valve and is discharged through the exhaust pipe; when the high-pressure control pressure is less than the exhaust pressure of the high-pressure stage compression mechanism, the exhaust chamber formed by the middle support and the bracket is connected to the inside of the housing through the bracket connection port and the high-pressure stage valve plate exhaust port, and the high-pressure stage compression mechanism does not perform compression but directly exhausts.

2. The multi-stage compressor according to claim 1, characterized in that: The low-pressure stage compression mechanism includes: a fixed scroll, a movable scroll, an unloading assembly and a low-pressure stage pressure control mechanism; The fixed scroll and the movable scroll are relatively matched and assembled; The fixed scroll is fixedly connected to an upper support which is interference-fitted in the compressor housing by bolts; The movable scroll is mounted on the top of the crankshaft; The upper part of the fixed scroll is provided with an air intake pipe, the bottom end of which is fixedly mounted on the upper part of the fixed scroll and is the same as its internal cavity, and the top end of which passes through the upper cover and is placed outside the compressor; The upper part of the fixed vortex is provided with an unloading assembly The fixed scroll exhaust port of the fixed scroll is provided with a low-pressure stage pressure control mechanism; The low-pressure stage pressure control mechanism comprises: a slider, a low-pressure stage valve plate and a spring; the low-pressure stage valve plate is installed at the mouth of the fixed vortex exhaust port, and a slider is arranged inside the low-pressure stage valve plate; the spring is installed in a spring groove at the edge of the fixed vortex exhaust port of the fixed vortex, and contacts the bottom of the slider; The low-pressure stage valve plate is provided with a low-pressure stage pressure control pipeline which is connected to the outside of the compressor; the system controls the low-pressure control pressure in the low-pressure stage pressure control pipeline to control the rising and falling of the slider, complete the opening and closing of the fixed scroll exhaust port, and realize the compression ratio control of the low-pressure stage compression mechanism.

3. The multi-stage compressor according to claim 2, characterized in that: A low-pressure valve plate exhaust port is provided on the side wall of the low-pressure valve plate; The low-pressure valve plate exhaust port and unloading assembly are both facing the suction pipe. The exhaust temperature of the low-pressure compression mechanism and the exhaust temperature of the intermediate unloading are higher than the suction temperature, so that the refrigerant in the suction pipe is heated, preventing the compressor from inhaling liquid refrigerant and compressing it.

4. The multi-stage compressor according to claim 1, characterized in that: The high-pressure stage compression mechanism comprises: a rotor, a cylinder body, a middle support, a bracket and a high-pressure stage pressure control mechanism; The rotor is mounted on the crankshaft; The bracket, the middle support and the cylinder body are fixedly connected to the upper support by bolts; The middle support and the bracket form an exhaust cavity, which is discharged through the exhaust pipe; The middle support is provided with a high-pressure exhaust check valve, which connects the high-pressure compression chamber formed by the rotor and the cylinder body and the high-pressure exhaust chamber formed by the middle support and the bracket; The high-pressure stage pressure control mechanism further comprises: a slider; the slider is assembled inside the high-pressure stage valve plate, and the high-pressure stage valve plate is assembled at the mouth of the bracket communication port; By controlling the high-pressure control pressure in the high-pressure stage pressure control pipeline through the system, the rising and falling of the slider is controlled, the closing and opening of the bracket connection port are completed, and the closing and connection of the exhaust chamber formed by the middle support and the bracket and the inside of the shell are further controlled, so as to control whether the high-pressure stage compression mechanism participates in the compression work.

5. The multi-stage compressor according to claim 4, characterized in that: A high-pressure stage valve plate exhaust port is arranged on the side wall of the high-pressure stage valve plate.

6. The multi-stage compressor according to claim 1, characterized in that: The low-pressure stage compression mechanism is provided with a low-pressure stage air supply pipe, the bottom end of the low-pressure stage air supply pipe is communicated with the low-pressure stage compression chamber composed of the fixed vortex and the movable vortex through the fixed vortex, and the top end is communicated with the outside of the upper cover; The high-pressure stage compression mechanism is provided with a high-pressure stage air supply pipe, which enters from the outside of the compressor housing to the inside through the cylinder body and the rotor and is connected to the high-pressure stage compression chamber formed by the cylinder body.

7. An air conditioning system, comprising the multi-stage compressor according to any one of claims 1 to 6; characterized in that: The air conditioning system further comprises: an expansion valve, a solenoid valve, a four-way reversing valve, a condenser, an economizer, an evaporator, a liquid storage tank and a capillary tube; The expansion valve is a general term, including multiple single expansion valves: expansion valve A, expansion valve B, expansion valve C and expansion valve D; The solenoid valve is a general term, including multiple single solenoid valves: solenoid valve A, solenoid valve B, solenoid valve C, solenoid valve D, solenoid valve E, solenoid valve F and solenoid valve G; The main output of the economizer is connected to the input end of the evaporator through the solenoid valve A and the expansion valve A, the output end of the evaporator is connected to the input end of the four-way reversing valve, and the output end of the four-way reversing valve is connected to the suction pipe of the multi-stage compressor; The auxiliary circuit of the economizer is connected to the high-pressure air supply pipe of the multi-stage compressor through the solenoid valve B; The auxiliary branch of the economizer is connected to the low-pressure gas supply pipe of the multi-stage compressor after the gas output from the auxiliary exhaust path before the condenser and the solenoid valve F is moderated through the solenoid valve C and the expansion valve B; The condenser front exhaust branch is connected to the high-pressure stage pressure control pipeline of the multi-stage compressor through a capillary tube, a solenoid valve D, a liquid storage tank, an expansion valve C, and a solenoid valve E; The rear end branch of the condenser is connected to the low pressure machine pressure control pipeline of the multi-stage compressor and the input end of the economizer through the solenoid valve G and the expansion valve D; The exhaust pipe of the multi-stage compressor is connected to the condenser through a four-way reversing valve.

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