New semi-hermetic twin-screw refrigeration compressor

Abstract

Provided is a semi-hermetic twin-screw refrigeration compressor, comprising a compressor shell, a screw rotor, a slide valve (13), an oil piston (11) and a permanent magnet synchronous electric motor (5). The permanent magnet synchronous electric motor (5) directly drives the screw rotor to rotate, and the capacity of the refrigeration compressor can be adjusted by regulating the rotational speed of the electric motor. A metal filter screen (1) is provided between an air inlet and the permanent magnet synchronous electric motor (5) and is used for filtering metal debris and protecting the electric motor. The slide valve (13) can adjust the internal volume ratio of the compressor to ensure that the highest coefficient of performance is obtained under variable working conditions, and can also adjust the capacity of the compressor, in coordination with the control over the rotational speed of the electric motor to maintain long-term operation of the compressor under an extremely low load without shutdown, achieving energy saving.

Description

A new type of semi-hermetic twin-screw refrigeration compressor Technical Field

[0001] The present invention relates to the technical field of compressors, in particular to a novel semi-enclosed twin-screw refrigeration compressor. Background Art

[0002] Existing screw refrigeration compressors all use a motor to drive the male rotor to rotate, and the male rotor drives the female rotor. The female and male rotors are engaged with each other, and the outer circle of the rotor cooperates with the housing. When the engaged rotor working pair rotates, the volume of the rotor tooth groove changes, thereby realizing the suction, compression and discharge of gas, thereby completing a continuous gas compression cycle.

[0003] Most screw refrigeration compressors are generally driven by asynchronous motors and are not suitable for variable frequency operation. Most semi-hermetic screw refrigeration compressors use sliding valves to adjust the capacity of the compressor. However, the sliding valve's energy regulation will cause the gas to be over-compressed at partial load, thereby reducing the COP value of the compressor. Since the opening of the sliding valve is fixed, this sliding valve can only achieve the best COP of the compressor when running at full load under specific working conditions, and it is powerless to cope with changes in working conditions. In order to adapt to changing working conditions, some manufacturers add a sliding valve to adjust its content volume ratio, which greatly increases the complexity of its structure and control, and also increases the cost a lot.

[0004] Most semi-hermetic screw compressors are only suitable for one type of refrigerant. This is due to design conditions and cost limitations. For example, ammonia and Freon have different requirements for motor and terminal materials, resulting in different dimensions and specifications. The sealing materials may also be different, which leads to different shell sizes. Of course, the bearing configuration may also be different. This is not conducive to standardized production and increases the production cost of the enterprise.

[0005] In order to solve the above problems, the present invention provides a novel semi-hermetic screw refrigeration compressor which is compatible with multiple refrigerants and has an adjustable content-to-volume ratio and variable frequency energy-saving functions.

[0006] Summary of the Invention

[0007] 1. Technical Problems to be Solved

[0008] The present invention addresses the above-mentioned defects of the prior art and proposes a new type of semi-hermetic screw refrigeration compressor, which solves the problems of high energy consumption of the existing semi-hermetic screw refrigeration compressor under partial load and changing operating conditions, and the single type of refrigerant applicable, while also solving the problem of high production costs. In addition, it also solves the problem of damage to the compressor caused by wet compression to the greatest extent.

[0009] 2. Technical Solution

[0010] In order to solve the above technical problems, the present invention provides a new type of refrigeration compressor, including a compressor housing, a compressor screw rotor, a slide valve and an oil piston arranged in the compressor housing, and a permanent magnet synchronous motor.

[0011] The permanent magnet synchronous motor is used to drive the compressor screw rotor to rotate; the displacement of the refrigeration compressor can be adjusted by controlling the speed of the permanent magnet synchronous motor; an air inlet is provided on the compressor housing near the end of the permanent magnet synchronous motor, and an exhaust port is provided on the compressor housing near the end of the compressor screw rotor; a metal filter is also provided between the air inlet and the permanent magnet motor, and the filter can be used to filter metal chips to protect the permanent magnet motor. A slide valve and an oil piston device that drives the slide valve are installed at the bottom of the screw rotor.

[0012] The compressor housing includes a body, an exhaust end seat, and an exhaust end cover;

[0013] The body is used to install the main parts of the motor and rotor and the slide valve, the exhaust end seat is used to install a part of the rotor shaft section; the exhaust end cover is used to install the oil piston device;

[0014] The body adopts double-wall structure;

[0015] The motor stator is mounted on the machine body;

[0016] The rotor of the motor is installed on the shaft end of the screw male rotor and is fixed with a baffle and screws.

[0017] The air inlet is arranged at the end of the machine body near the position where the motor is installed, and the filter is installed on the upper part of the machine body.

[0018] Among them, the metal filter is cylindrical and has an air intake check valve inside.

[0019] Among them, a fixing plate is provided at the bottom of the compressor body, and the fixing plate is used for fixing and installing the refrigeration compressor.

[0020] Among them, the compressor screw rotor includes a male rotor and a female rotor, and the permanent magnet synchronous motor is used to drive the male rotor to rotate.

[0021] Among them, the speed of the permanent magnet synchronous motor is controlled by a frequency converter. 3. Beneficial Effects

[0022] Compared with the existing technology, the refrigeration compressor of the present invention utilizes a permanent magnet synchronous variable frequency motor and a slide valve to solve the problem of high energy consumption of existing semi-hermetic screw refrigeration compressors under partial load and changing operating conditions. At the same time, one compressor is suitable for multiple refrigerants and multiple operating conditions, reducing production costs. In addition, without increasing costs, the compressor also provides a good solution to the problem of wet compression by relying on the control logic of the slide valve, greatly improving the reliability of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a cross-sectional view 1 of the present invention;

[0024] Figure 2 is a cross-sectional view 2 of the present invention;

[0025] FIG3 is a perspective view of a rotor component of the present invention;

[0026] FIG4 is a perspective view of the present invention;

[0027] FIG5 is a state diagram of the present invention.

[0028] In the figure: 1 is a metal filter; 2 is a screw male rotor; 3 is a screw female rotor; 4 is an air intake cover; 5 is a permanent magnet synchronous motor; 7 is a terminal; 8 is a machine body; 9 is an exhaust terminal seat; 10 is a displacement sensor; 11 is an oil piston; 13 is a slide valve. DETAILED DESCRIPTION

[0029] The present invention will be described below based on the embodiments with reference to the accompanying drawings in the embodiments of the present invention. However, it is worth noting that the present invention is not limited to these embodiments. In the detailed description of the present invention below, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present invention.

[0030] In addition, those skilled in the art should understand that the drawings are only provided to illustrate the purpose, features and advantages of the present invention, and are not actually drawn to scale.

[0031] At the same time, unless the context clearly requires otherwise, words such as "include", "comprising" and the like throughout the specification and claims should be interpreted as inclusive rather than exclusive or exhaustive; that is, as "including but not limited to".

[0032] As shown in Figures 1 and 2, the new refrigeration compressor of this embodiment includes a compressor body 8, and a compressor male rotor 2 and a female rotor 3 arranged in the compressor body 8, and a slide valve 13 installed under the screw rotor; the permanent magnet synchronous motor 5 is used to drive the compressor screw male rotor 2 to rotate; by controlling the speed of the permanent magnet synchronous motor 5, the exhaust volume of the refrigeration compressor can be adjusted; an air inlet is provided on the compressor body 1 near one end of the permanent magnet motor 5, and an exhaust port is provided at one end of the exhaust end seat 9 of the compressor; a metal filter 1 is also provided between the air inlet and the permanent magnet motor 5, and the metal filter 1 can be used to filter metal chips to protect the permanent magnet synchronous motor 5 and the screw male rotor 2 and the female rotor 3.

[0033] Most screw refrigeration compressors are driven by asynchronous fixed-frequency motors, and most semi-hermetic screw refrigeration compressors use sliding valves to adjust the exhaust volume of the compressor. However, the sliding valve adjustment energy will cause the gas to be over-compressed at partial load, thereby reducing the COP value of the compressor. Since the opening of the sliding valve is certain, this sliding valve can only achieve the best COP of the compressor when running at full load under specific working conditions, and it is powerless to cope with changes in working conditions. In order to adapt to changing working conditions, some manufacturers add a sliding valve to adjust its content volume ratio, which greatly increases the complexity of its structure, the complexity of control, and the cost.

[0034] Therefore, based on the above problems, the refrigeration compressor implemented in this example uses a sliding valve to adjust the content volume ratio of the compressor to ensure that the compressor can obtain the highest COP under variable operating conditions. In addition, this sliding valve can also adjust the capacity of the compressor within a certain range. Combined with the speed control of the permanent magnet synchronous motor, the compressor can be maintained to run for a long time without stopping at an extremely low load, thereby achieving energy saving. In addition, through the control of the sliding valve, when it is determined that the compressor is in a wet compression state, the sliding valve is moved toward the motor side to the position where its content ratio is minimum. In this way, the opening of the sliding valve is connected to the compressor exhaust in advance, and the pressure in the rotor cavity no longer continues to rise. Even if there is wet compression, the compressor can be protected from damage.

[0035] Moreover, because the volume ratio adjustment range of this embodiment is very wide and covers all working conditions, this embodiment has only one slide valve, which replaces the traditional slide valve method of adopting different openings according to different working conditions, is also conducive to standardized production and reduces costs.

[0036] Furthermore, the compressor body of this embodiment adopts a double-wall structure, the inner wall and the rotor together form a closed space, the upper part of the outer wall is filled with refrigerant gas, and the lower part of the outer wall is refrigeration oil and separated liquid refrigerant. Such a structure has a stronger pressure-bearing capacity. Because the inner and outer walls are filled with gas, the compressor has lower noise, and the gas on the outer wall can be used to cool the inner wall.

[0037] In this embodiment, the air intake port is above the rotor and the air exhaust port is below the rotor. Such an arrangement is more conducive to the separation of air and liquid.

[0038] As shown in FIG1 , the air inlet is arranged at the upper part of the machine body, with its central axis being perpendicular to the rotor axis. A metal filter screen 1 is installed therein, and an air intake check valve is provided therein.

[0039] A fixing plate is provided at the bottom of the machine body 8, and the fixing plate is used for fixing and installing the refrigeration compressor.

[0040] The screw rotor of the compressor includes a male rotor 2 and a female rotor 3. The permanent magnet synchronous motor 5 is used to drive the male rotor 1 to rotate. The speed of the permanent magnet synchronous motor 5 is controlled by a frequency converter.

[0041] In this embodiment, the different motor powers required for different refrigerants have been comprehensively considered during the design stage, and different motors have been customized to make them suitable for the same compressor housing. The length of the rotor extending out of the shaft and the installation space have been reserved for this purpose. Therefore, for different refrigerants, only the motor, terminal board and sealing material need to be replaced.

[0042] [Corrected 11.03.2024 according to Rule 26] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. [Corrected 11.03.2024 in accordance with Rule 26] A novel semi-hermetic twin-screw refrigeration compressor, characterized in that: and a compressor screw rotor, a slide valve and an oil piston, and a permanent magnet synchronous motor disposed in the compressor housing; The permanent magnet synchronous motor is directly connected to the screw male rotor and is used to drive the compressor screw male rotor to rotate; By controlling the speed of the permanent magnet synchronous motor, the exhaust volume of the refrigeration compressor can be adjusted; An air inlet is provided on the compressor housing near one end of the permanent magnet synchronous motor, and an exhaust port is provided on the compressor housing near one end of the compressor screw rotor; a metal filter is also provided between the air inlet and the permanent magnet synchronous motor, and the filter can be used to filter metal chips to protect the permanent magnet synchronous motor.

2. A novel semi-hermetic twin-screw refrigeration compressor according to claim 1, characterized in that: The novel refrigeration compressor further includes a slide valve and an oil piston device for driving the slide valve. The slide valve is installed below the screw rotor, and the oil piston is used to drive the movement of the slide valve. This slide valve can not only steplessly adjust the internal volume ratio of the compressor, but also steplessly adjust the exhaust volume of the compressor within a certain range. In addition, when it is determined that the compressor has wet compression, the slide valve can be controlled to move to the far left, that is, the position with the smallest internal volume ratio, thereby avoiding damage to the compressor caused by wet compression to the greatest extent.

3. [Corrected 11.03.2024 according to Rule 26] A novel semi-hermetic twin-screw refrigeration compressor according to claim 2, characterized in that: The adjustment range of the volume ratio of the compressor slide valve is very wide, covering the volume ratios corresponding to all working conditions of the compressor, so the same specification of slide valve is used for compressors of various working conditions.

4. [Corrected 11.03.2024 according to Rule 26] A novel semi-hermetic twin-screw refrigeration compressor according to claim 1, characterized in that: The compressor housing includes a body, an exhaust end seat, and an exhaust end cover; The stator of the permanent magnet synchronous motor is mounted on the body; The rotor of the permanent magnet synchronous motor is mounted on the shaft end of the screw male rotor and fixed with a baffle and screws.

5. [Corrected 11.03.2024 according to Rule 26] A novel semi-hermetic twin-screw refrigeration compressor according to claim 1, characterized in that: The air inlet is set at the upper part of the machine body, with its central axis perpendicular to the rotor axis. A metal filter is installed here, and an air suction check valve is installed inside. The refrigerant flows in the rotor from top to bottom.

6. A novel semi-hermetic twin-screw refrigeration compressor according to claim 1, characterized in that: A fixing plate is provided at the bottom of the compressor body, and the fixing plate is used for fixing and installing the refrigeration compressor.

7. A novel semi-hermetic twin-screw refrigeration compressor according to claim 1, characterized in that: The compressor screw rotor includes a male rotor and a female rotor, and the permanent magnet synchronous drive is used to drive the male rotor to rotate.

8. A novel semi-hermetic twin-screw refrigeration compressor according to claim 1, characterized in that: The speed of the permanent magnet synchronous motor is controlled by a frequency converter.

9. A novel semi-hermetic twin-screw refrigeration compressor according to claims 1-8, characterized in that Compatible with different refrigerants, including but not limited to R744, R717, R22, R507A, R404A, R134a, etc. For different refrigerants, only the motor, terminal board and sealing materials need to be replaced.

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