Multi-stage compressor and air conditioning system

Abstract

The invention belongs to the technical field of air conditioner compressors, and particularly relates to a multi-stage compressor and an air conditioner system. A low-pressure-stage compression mechanism and a high-pressure-stage compression mechanism are arranged in the multi-stage compressor; the low-pressure-stage compression mechanism adopts a scroll compression mechanism and comprises a low-pressure-stage pressure control mechanism which can control the compression ratio of the low-pressure-stage compression mechanism to the high-pressure-stage compression mechanism of the compressor; the high-pressure-stage compression mechanism is a rotor type compression mechanism and comprises a high-pressure-stage pressure control mechanism which can control exhaust of the high-pressure-stage compression mechanism to be communicated with exhaust of the low-pressure-stage compression mechanism. The multi-stage compressor has a first working state in which only the low-pressure-stage compression mechanism participates in 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 compression work; according to the technical scheme, the problem that the overall energy efficiency of the compressor needs to be improved due to undercompression of the first-stage compression mechanism in an existing multi-stage compressor technology in the prior art is solved.

Description

Technical Field

[0001] The invention discloses a multi-stage compressor and an air-conditioning system, and relates to the technical field of air-conditioning compressors, and in particular to a multi-stage compressor and an air-conditioning system using the multi-stage compressor. Background Art

[0002] In the past, various multi-stage compressors suitable for air conditioning systems have been disclosed. Japanese Patent Application Laid-Open No. 5-87074 and Japanese Patent No. 4875484 propose a two-stage compressor having 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 propose to use a gas injection economizer to achieve high efficiency and high capacity of two-stage compression.

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

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

[0006] It can be seen from the above patents that the published multi-stage compressor structure has a low-pressure stage of a rotor compressor structure, a high-pressure stage of a rotor compressor or a scroll compressor structure, and the low-pressure stage side compression structure has no exhaust control structure. The existing scroll compressor has a higher energy efficiency level than the rotor compressor. When only unipolar compression is running, the scroll compressor structure should be given priority considering the energy efficiency level. At the same time, when the compressor is operating under high-pressure ratio conditions and ultra-high-pressure ratio conditions, that is, low-temperature heating conditions and ultra-low-temperature heating conditions, the compressor operating efficiency is low. At this time, the compression capacity of the low-pressure stage compressor in the multi-stage compressor is low, and the compression ratio is improved less, while the high-pressure stage compressor is always in an under-compressed working state, so the overall energy efficiency level is low. Under the working conditions of the intermediate compression ratio, that is, the conventional refrigeration working conditions, there is also the situation of under-compression of the high-pressure stage compressor. Under the extremely low pressure ratio working conditions, that is, the low-temperature refrigeration working conditions, it is possible that the multi-stage compressors are all in an over-compressed state.

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

[0008] In view of the problems existing in the above-mentioned prior art, it is very necessary to study 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] According to 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 by 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: A multi-stage compressor, comprising a compressor; the compressor further comprises: an air intake pipe, an upper cover, a fixed scroll, a movable scroll, an upper support, a rotor, a cylinder block, a middle support, a bracket, a crankshaft, a motor, a lower support assembly, an oil pump, an oil pool and a lower cover; characterized in that: Furthermore, a low-pressure stage compression mechanism and a high-pressure stage compression mechanism are also provided in the compressor, constituting a multi-stage compressor; 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 ratio of the low-pressure stage compression mechanism and the high-pressure stage compression mechanism of the compressor; Furthermore, the high-pressure stage compression mechanism adopts a rotor-type compression mechanism, including a high-pressure stage pressure control mechanism, 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 the low-pressure stage compression mechanism and the high-pressure stage compression mechanism jointly participate in the compression work; Furthermore, the multi-stage compressor also includes an exhaust guide pipe; the exhaust guide pipe passes through the fixed scroll, upper support, cylinder body, middle support, and bracket to connect the upper cover with the motor side. After the low-pressure compression mechanism is exhausted, the exhausted refrigerant and refrigeration oil mist enter the motor and oil pool from the upper cover through the exhaust guide pipe. After passing through the motor, the refrigerant passes through the upper support, cylinder body, middle support, and bracket and is compressed with the shell to flow upward to the middle part of the upper support, 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 remains in the motor and the oil pool, thereby realizing motor cooling, oil and gas separation, and reducing the oil discharge of the compressor.

[0011] Further, the low-pressure stage compression mechanism includes: a fixed scroll, a movable scroll, an unloading assembly and a low-pressure stage pressure control mechanism; Furthermore, the fixed scroll and the movable scroll are relatively matched and assembled; Further, the fixed scroll is fixedly connected to the upper support in the compressor housing by bolts and interference fit; Further, the movable scroll is mounted on the top of the crankshaft; Furthermore, an air intake pipe is provided on the upper part of the fixed scroll, the bottom end of the air intake pipe is fixedly mounted on the upper part of the fixed scroll and communicates with the internal cavity thereof, and the top end of the air intake pipe passes through the upper cover and is placed outside the compressor; Furthermore, an unloading assembly is provided on the upper portion of the fixed scroll; Further, a low-pressure stage pressure control mechanism is provided at the mouth of the fixed scroll exhaust port of the fixed scroll; Furthermore, the low-pressure stage pressure control mechanism comprises: a slider B, 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 B 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 with the bottom of the slider B; Furthermore, a low-pressure stage pressure control pipeline connected to the outside of the compressor is arranged 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 rising and falling of the slider B is controlled to complete the opening and closing of the fixed vortex exhaust port, thereby realizing the compression ratio control of the low-pressure stage compression mechanism.

[0012] Further, the high-pressure stage compression mechanism includes: a rotor, a cylinder body, a middle support, a bracket and a high-pressure stage pressure control mechanism; Further, the rotor is mounted on the crankshaft; Further, the bracket, the middle support and the cylinder body are fixedly connected to the upper support by bolts; Furthermore, the middle support and the bracket form an exhaust cavity, which is discharged through the exhaust pipe; Furthermore, a high-pressure exhaust check valve is provided on the middle support, and the high-pressure exhaust check valve 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; Furthermore, a bracket communication port is provided at the bottom of the bracket, and a high-pressure level pressure control mechanism is installed at the mouth of the bracket communication port; Furthermore, the high-pressure stage pressure control mechanism comprises: a high-pressure stage valve plate and a slider A; the high-pressure stage valve plate is mounted on the mouth of the bracket communication port, and the slider A is mounted inside the high-pressure stage valve plate; Furthermore, a high-pressure stage pressure control pipeline connected to the outside of the compressor casing is provided on the high-pressure stage valve plate; the system controls the high-pressure control pressure in the high-pressure stage pressure control pipeline to control the floating and falling of the slider A, complete the closing and opening of the bracket connection port, and further control the closing and connection between the exhaust chamber formed by the middle support and the bracket and the inside of the casing, thereby realizing the control of whether the high-pressure stage compression mechanism participates in the compression work.

[0013] Furthermore, a low-pressure air supply pipe is provided in the low-pressure compression mechanism, the bottom end of the low-pressure air supply pipe is communicated with the low-pressure 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; Furthermore, a high-pressure air supply pipe is provided in the high-pressure compression mechanism, and the high-pressure air supply pipe enters from the outside of the compressor casing to the inside through the cylinder body and the rotor and is connected to the high-pressure compression chamber formed by the cylinder body.

[0014] Furthermore, a low-pressure stage valve plate exhaust port is provided on the side wall of the low-pressure stage valve plate; Furthermore, the exhaust port of the low-pressure valve plate and the 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, thereby preventing the compressor from inhaling liquid refrigerant and compressing it.

[0015] An air conditioning system using a multi-stage compressor, comprising a multi-stage compressor; characterized in that: the air conditioning system also 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; Furthermore, the expansion valve is a general term, including a plurality of individual expansion valves, namely: expansion valve A, expansion valve B, expansion valve C and expansion valve D; Furthermore, the solenoid valve is a general term, including a plurality of individual solenoid valves, namely: solenoid valve A, solenoid valve B, solenoid valve C, solenoid valve D, solenoid valve E, solenoid valve F and solenoid valve G; Furthermore, 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; Further, the auxiliary circuit of the economizer is connected to the high-pressure stage air supply pipe of the multi-stage compressor through the solenoid valve B; Furthermore, the auxiliary branch of the economizer is connected to the low-pressure gas supply pipe of the multi-stage compressor after being moderated by the gas output from the auxiliary exhaust circuit before the condenser and the solenoid valve F through the solenoid valve C and the expansion valve B; Further, the exhaust branch before 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; Furthermore, 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 the solenoid valve G and the expansion valve D.

[0016] Furthermore, the exhaust pipe of the multi-stage compressor is connected to the condenser through a four-way reversing valve.

[0017] The multi-stage compressor and air-conditioning system adopted by the present invention control the exhaust opening or closing of the low-pressure compression mechanism by the exhaust pressure in the system, thereby controlling the pressure ratio of the low-pressure compression mechanism, and then control the exhaust opening or closing of the high-pressure compression mechanism by the exhaust pressure in the system, thereby controlling whether the high-pressure compression mechanism is working, thereby achieving that the two compression mechanisms of the compressor can be in a more efficient working state under various pressure ratio conditions, thereby greatly improving the efficiency of the compressor and making the energy-saving effect of the air-conditioning system more obvious.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The multi-stage compressor provided by the present invention can realize the exhaust pressure control of the first stage compression and the control of 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, thereby realizing the energy efficiency improvement of all working conditions; 2. The multi-stage compressor provided by the present invention can greatly improve the working conditions of over-compression of the first-stage compressor or under-compression of the second-stage compressor, and achieve a wide operating range working capacity of 1.2 to 64 times the pressure ratio, which greatly improves the problem of small operating range of existing multi-stage compressors; 3. The multi-stage compressor provided by the present invention has a simple structure, low design cost, and a wide range of applications. Combined with the system control method provided by the present invention, it can be generally applied to current air-conditioning units.

[0019] 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 in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 It is a schematic diagram of the structure of a multi-stage compressor of the present invention; Figure 2 It is a schematic diagram of the structure of the low-pressure stage pressure control mechanism in the multi-stage compressor of the present invention; Figure 3 It is a schematic diagram of the structure of the high-pressure stage pressure control mechanism in the multi-stage compressor of the present invention; Figure 4 This is a schematic diagram of the refrigeration cycle of an air-conditioning system using a multi-stage compressor according to the present invention.

[0022] In the figure: 1, air intake pipe; 2, upper cover; 3, fixed scroll; 4, movable 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 pool; 16, lower cover; 17, unloading assembly; 18, high pressure stage pressure control mechanism; 19, high pressure stage pressure control pipeline; 20, low Pressure control mechanism; 21. Low-pressure pressure control pipeline; 22. Low-pressure air supply pipe; 23. High-pressure air supply pipe; 24. Exhaust pipe; 25. Slider A; 26. Bracket connecting port; 27. Low-pressure valve plate; 28. Slider B; 29. ​​Spring; 30. Fixed vortex exhaust port; 31. Low-pressure valve plate exhaust port; 32. High-pressure exhaust check valve; 33. High-pressure valve plate exhaust port; 34. High-pressure 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 DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0027] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0028] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0029] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0030] As shown in the figure, the present invention provides a multi-stage compressor, including a low-pressure stage compression mechanism and a high-pressure stage compression mechanism, the low-pressure stage compression mechanism adopts a vortex compression structure, and the high-pressure stage compression mechanism adopts a rotor compression mechanism. Considering that the vortex structure has a higher operating efficiency than the rotor structure, its efficient compression range is 3-6 times the compression ratio, while the efficient 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. Because the high-pressure stage compression mechanism of the present invention includes a high-pressure stage pressure control mechanism 18, it 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 the low-pressure stage compression mechanism and the high-pressure stage compression mechanism jointly participate in the compression work. 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 multi-stage compressor to adjust the overall capacity energy efficiency level of the compressor, thereby improving the overall energy efficiency level of the compressor.

[0031] like Figure 1-3 As shown, the multi-stage compressor includes a compressor; the compressor further includes: an air intake pipe 1, an upper cover 2, a fixed scroll 3, a movable 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 pool 15 and a lower cover 16; like Figure 1-3 As shown, a low-pressure stage compression mechanism and a high-pressure stage compression mechanism are also provided in the compressor, forming a multi-stage compressor 37; like Figure 2 As 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; like Figure 3 As shown, the high-pressure stage compression mechanism adopts a rotor-type compression mechanism, including a high-pressure stage pressure control mechanism 18, 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 the low-pressure stage compression mechanism and the high-pressure stage compression mechanism participate in the compression work together; like Figure 1As 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 body 8, the middle support 9, and the bracket 10, connecting the upper cover 2 with the motor 12 side. After the low-pressure stage compression mechanism is exhausted, the exhausted refrigerant and the refrigeration oil mist enter the motor 12 and the oil pool 15 from the upper cover 2 through the exhaust guide pipe. After passing through the motor 12, the refrigerant flows upward to the middle part of the upper support 5 through the channel surrounded by the upper support 5, the cylinder body 8, the middle support 9, and the bracket 10 after being pressed together, and is sucked into the compression chamber by the high-pressure stage compression mechanism for secondary compression. The refrigeration oil has a higher density than the medium-temperature refrigerant, and more of it remains in the motor 12 and the oil pool 15, thereby realizing motor cooling, oil and gas separation, and reducing the oil discharge amount of the compressor.

[0032] like Figure 2 As shown, the low-pressure stage compression mechanism includes a fixed scroll 3, a movable scroll 4, an unloading assembly 17, and a low-pressure stage pressure control mechanism 20; The low-pressure stage pressure control mechanism 20 is connected to the low-pressure stage pressure control pipeline 21. After the low-pressure stage pressure control mechanism 20 is opened, the first-stage exhaust generated by the fixed scroll 3 and the movable scroll 4 working and compressing 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 movable scroll 4 continue to operate as a 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 connected to the low-pressure stage pressure control pipeline 21, and a low-pressure stage valve plate exhaust port 31 is provided 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. The low-pressure control pressure exists 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 compression mechanism and the spring 29 is less than the low-pressure control pressure, the slider B28 falls and closes, the fixed scroll exhaust port 30 is closed, and the fixed scroll 3 and the movable scroll 4 continue to work as compressors; when the combined force formed by the exhaust pressure of the low-pressure compression mechanism and the spring 29 is greater than the low-pressure control pressure, the slider B28 floats and opens, the fixed scroll exhaust port 30 opens, and is connected to the low-pressure valve plate exhaust port 31, and the low-pressure compression mechanism exhausts air to the inside of the upper cover 2.

[0033] The controllable pressure ratio of the low-pressure stage compression mechanism makes it possible to adjust the compression amount of each stage of compression of the compressor, which can fully avoid the situation where the first stage compression is under-compressed and the second stage compression is still under-compressed. Although under ultra-large pressure ratio conditions, such as operating at a pressure ratio of 20 times (that is, the exhaust pressure is 20 times the suction pressure) or more, the multi-stage compressor structure disclosed in the present invention may still have a situation where both the first stage compressor and the second stage compression are under-compressed, but providing control over the exhaust pressure of the first stage compression can effectively improve the degree of under-compression of the second stage compression, thereby greatly improving the operating efficiency of the compressor.

[0034] like Figure 3 As shown, the high-pressure stage compression mechanism includes a rotor 7, a cylinder body 8, a middle support 9, a bracket 10, and a high-pressure stage pressure control mechanism 18; The high-pressure stage pressure control mechanism 18 is connected to the high-pressure stage pressure control pipeline 19. When the high-pressure stage pressure control mechanism 18 is closed, the second-stage exhaust generated by the working compression of the rotor 7 and the cylinder body 8 passes through the exhaust chamber formed by the middle support 9 and the bracket 10, and is exhausted through the exhaust pipe 24; when the high-pressure stage pressure control mechanism 18 is opened, the exhaust chamber formed by the middle support 9 and the bracket 10 is connected to the first-stage exhaust, and the high-pressure stage compression mechanism does not perform compression but directly exhausts the exhaust.

[0035] The high-pressure stage pressure control mechanism 18 is composed 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. The high-pressure stage valve plate 34 is provided with a high-pressure stage valve plate exhaust port 33. The high-pressure stage pressure control mechanism 18 is fixed below the bracket connection port 26.

[0036] 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, the bracket connection port 26 is closed, the rotor 7 and the cylinder body 8 continue to work as a compressor, and the gas enters the exhaust chamber 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 falls and opens, and the exhaust chamber formed by the middle support 9 and the bracket 10 is connected to the inside of the shell through the bracket connection port 26 and the high-pressure stage valve plate exhaust port 33, that is, connected to the first-stage exhaust, and the high-pressure stage compression mechanism does not perform compression but directly exhausts.

[0037] When the compressor operates at a low pressure ratio, for example, when the compression ratio is lower than 3, the high-pressure stage pressure control mechanism 18 prevents the high-pressure stage compression mechanism from performing compression, thereby greatly improving the low operating efficiency of the compressor caused by over-compression due to the second-stage compression. At the same time, an unloading assembly 17 is arranged on the fixed scroll 3 of the low-pressure stage compression mechanism, so that in the first working state in which only the low-pressure stage compressor participates in the compression work, exhaust is further advanced under the low pressure ratio condition, thereby further avoiding over-compression and improving operating efficiency.

[0038] like Figure 4 As shown, an air conditioning system using a multi-stage compressor includes a multi-stage compressor 37; characterized in that: the air conditioning system also 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; The expansion valve 35 is a general term, including a plurality of single expansion valves, namely: expansion valve A 35a, expansion valve B 35b, expansion valve C 35c and expansion valve D 35d; The solenoid valve 36 is a general term, including a plurality of individual 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; The main output of the economizer 40 is connected to the input end of the evaporator 41 through the solenoid valve A36a and the expansion valve A35a, and the output end of the evaporator 41 is connected to the input end of the four-way reversing valve 38, and the output end of the four-way reversing valve 38 is connected to the suction pipe 1 of the multi-stage compressor 37; The auxiliary circuit of the economizer 40 is connected to the high-pressure stage air supply pipe 23 of the multi-stage compressor 37 through the solenoid valve B36b; The auxiliary branch of the economizer 40 is connected to the low-pressure air supply pipe 22 of the multi-stage compressor 37 after being moderated by the gas output from the exhaust auxiliary road before the condenser 39 and the solenoid valve F36f through the solenoid valve C36c and the expansion valve B35b; the exhaust auxiliary road before the condenser 39 contains high-temperature steam, and the auxiliary branch of the economizer 40 contains 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 the gas-liquid mixed refrigerant, which can improve the air supply reliability of the compressor and further improve the air supply or gas-liquid mixed spray effect.

[0039] The exhaust branch before the condenser 39 is connected to the high-pressure stage pressure control pipeline 19 of the multi-stage compressor 37 through the capillary tube 43, the solenoid valve D36d, the liquid storage tank 42, the expansion valve C35c, and the solenoid valve E36e; 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.

[0040] The exhaust pipe 1 of the multi-stage compressor 37 is connected to the condenser 39 via a four-way reversing valve 38; Through the cooperation between 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 opening and closing pressure control functions, thereby improving the operating efficiency of the compressor and even the system.

[0041] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to 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: An air intake pipe (1), an upper cover (2), a fixed scroll (3), a movable 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 pool (15) and a lower cover (16); the characteristics are: The compressor is also provided with a low-pressure stage compression mechanism and a high-pressure stage compression mechanism, forming a multi-stage compressor (37); The low-pressure stage compression mechanism adopts a scroll compression mechanism, and includes 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; The high-pressure stage compression mechanism adopts a rotor-type 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; The multi-stage compressor further comprises an exhaust guide pipe (6); the exhaust guide pipe (6) passes through the fixed scroll (3), the upper support (5), the cylinder body (8), the middle support (9), and the bracket (10), and connects the upper cover (2) with the motor (12). After the low-pressure stage compression mechanism is exhausted, the exhausted refrigerant and refrigeration oil mist enter the motor (12) and the oil pool (15) from the upper cover (2) through the exhaust guide pipe. After the refrigerant passes through the motor (12), it flows upward to the middle part of the upper support (5) through the channel formed by the upper support (5), the cylinder body (8), the middle support (9), and the bracket (10) after being compressed with the shell, and is sucked into the compression chamber by the high-pressure stage compression mechanism for secondary compression. The refrigeration oil has a higher density than the medium-temperature refrigerant, and more of it remains in the motor (12) and the oil pool (15), thereby achieving motor cooling, oil and gas separation, and reducing the oil discharge amount of the compressor.

2. The multi-stage compressor according to claim 1, characterized in that: The low-pressure stage compression mechanism comprises: a fixed scroll (3), a movable scroll (4), an unloading assembly (17) and a low-pressure stage pressure control mechanism (20); The fixed scroll (3) and the movable scroll (4) are assembled in relative cooperation; The fixed scroll (3) is fixedly connected to the upper support (5) in the compressor housing by means of bolts and interference fit; The movable scroll (4) is mounted on the top of the crankshaft (11); An air intake pipe (1) is arranged on the upper part of the fixed scroll (3); the bottom end of the air intake pipe (1) is fixedly mounted on the upper part of the fixed scroll (3) and communicates with the internal cavity thereof; the top end of the air intake pipe (1) passes through the upper cover (2) and is arranged outside the compressor; An unloading assembly (17) is provided on the upper portion of the fixed scroll (3); A low-pressure level pressure control mechanism (20) is provided at the mouth of the fixed scroll exhaust port (30) of the fixed scroll (3); The low-pressure stage pressure control mechanism (20) comprises: a slider B (28), a low-pressure stage valve plate (27) and a spring (29); the low-pressure stage valve plate (27) is mounted at the mouth of the fixed scroll exhaust port (30), and the slider B (28) is arranged inside the low-pressure stage valve plate (27); the spring (29) is mounted in a spring groove at the edge of the fixed scroll exhaust port (30) of the fixed scroll (3), and is in contact with the bottom of the slider B (28); The low-pressure stage valve plate (27) is provided with a low-pressure stage pressure control pipeline (21) which is in communication with the outside of the compressor; by controlling the low-pressure control pressure in the low-pressure stage pressure control pipeline (21) through the system, the floating and falling of the slider B (28) are controlled to complete the opening and closing of the fixed scroll exhaust port (30), thereby realizing 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 (31) is provided on the side wall of the low-pressure valve plate (27); The low-pressure stage valve plate exhaust port (31) and the unloading assembly (17) are both oriented toward the suction pipe (1). 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, thereby preventing the compressor from sucking in 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 (7), a cylinder body (8), a middle support (9), a bracket (10) and a high-pressure stage pressure control mechanism (18); The rotor (7) is mounted on a crankshaft (11); The bracket (10), the middle support (9) and the cylinder body (8) are fixedly connected to the upper support (5) by bolts; The middle support (9) and the bracket (10) form an exhaust cavity, which is discharged through the exhaust pipe (24); A high-pressure exhaust check valve (32) is provided on the middle support (9), and the high-pressure exhaust check valve (32) connects a high-pressure compression chamber formed by the rotor (7) and the cylinder body (8) and a high-pressure exhaust chamber formed by the middle support (9) and the bracket (10); The bottom of the bracket (10) is provided with a bracket communication port (26), and the mouth of the bracket communication port (26) is equipped with a high-pressure level pressure control mechanism (18); The high-pressure stage pressure control mechanism (18) comprises: a high-pressure stage valve plate (34) and a slider A (25); the high-pressure stage valve plate (34) is mounted on the mouth of the bracket communication port (26), and the slider A (25) is mounted inside the high-pressure stage valve plate (34); The high-pressure stage valve plate (34) is provided with a high-pressure stage pressure control pipeline (19) which is in communication with the outside of the compressor housing. By controlling the high-pressure control pressure in the high-pressure stage pressure control pipeline (19) through the system, the floating and falling of the slider A (25) are controlled to complete the closing and opening of the bracket connection port (26), and the closing and connection between the exhaust chamber formed by the middle support (9) and the bracket (10) and the inside of the housing are further controlled, so as to realize the control of 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 (33) is provided on the side wall of the high-pressure stage valve plate (34).

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 (22), the bottom end of the low-pressure stage air supply pipe (22) is communicated with the low-pressure stage compression chamber composed of the fixed scroll (3) and the movable scroll (4) through the fixed scroll (3), and the top end of the low-pressure stage air supply pipe (22) is communicated with the outside of the upper cover (2); The high-pressure stage compression mechanism is provided with a high-pressure stage air supply pipe (23), which enters from the outside of the compressor housing to the inside through the cylinder body (8) and the rotor (7) and is connected to the high-pressure stage compression chamber formed by the cylinder body (8).

7. An air conditioning system, comprising a multi-stage compressor (37); characterized in that: The air conditioning system further comprises: 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); The expansion valve (35) is a general term, including a plurality of single expansion valves, namely: expansion valve A (35a), expansion valve B (35b), expansion valve C (35c) and expansion valve D (35d); The solenoid valve (36) is a general term, including a plurality of individual 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); The main output of the economizer (40) is connected to the input end of the evaporator (41) via 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 the output end of the four-way reversing valve (38) is connected to the suction pipe (1) of the multi-stage compressor (37); The auxiliary circuit of the economizer (40) is connected to the high-pressure air supply pipe (23) of the multi-stage compressor (37) via a solenoid valve B (36b); The auxiliary branch of the economizer (40) is connected to the low-pressure gas supply pipe (22) of the multi-stage compressor (37) after the gas output from the auxiliary exhaust path before the condenser (39) and the solenoid valve F (36f) is moderated through the solenoid valve C (36c) and the expansion valve B (35b); 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 a capillary tube (43), a solenoid valve D (36d), a liquid storage tank (42), an expansion valve C (35c), and a solenoid valve E (36e); 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 G (36g) and the expansion valve D (35d); The exhaust pipe (24) of the multi-stage compressor (37) is connected to the condenser (39) via a four-way reversing valve (38).

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