The status quo and development trend of compressor technology

Compressor is a machine used to increase gas pressure and convey gas, which is a working machine that converts the power energy of the prime mover into gas pressure energy. It is called "general machinery" because of its wide variety and wide application. At present, in addition to piston compressors, other compressor models, such as centrifugal, twin-screw, rolling rotor and scroll, have been effectively developed and utilized, providing more possibilities for users to choose models.

1. Current status and development trend of compressor technology:

1. Turbo compressor

In the petrochemical industry, the current domestic centrifugal compressors cannot meet domestic demand in terms of high technology and special products. In addition, there is still a gap with foreign countries in terms of technical level, quality and completeness. With the continuous expansion of my country's petrochemical production scale, centrifugal compressors will face large-scale new problems. There is no mature experience in designing and manufacturing these large-scale gas compressors in China. Centrifugal compressors need to be developed to large capacity to meet the requirements of my country's expansion of petrochemical production scale. At the same time, with the development of new technologies, the emergence of new gas seals, magnetic bearings and non-lubricated couplings, the development trends of turbo compressors mainly include: continuous development of high-pressure and small-flow products; further research on three-dimensional flow theory and its application It is based on the design of impeller, vane diffuser and other components to realize the unit. Low noise, noise protection is adopted to improve the operating environment.

In the field of refrigeration and air conditioning, turbo compressors still have advantages in a large refrigeration capacity range. The centrifugal compressor has few and simple moving parts and low manufacturing precision, so the manufacturing cost is relatively low and the reliability is high. Due to the influence of screw compressors and absorption chillers, the development of centrifugal refrigeration compressors is relatively slow. Under current technical conditions, centrifugal refrigeration compressors are mainly used for air conditioning in large buildings, and their demand is small. In recent years, due to the launch of large-scale infrastructure projects, centrifugal refrigeration compressors have become the focus of attention.

2. Reciprocating compressor

In the petrochemical field, reciprocating compressors are mainly developing in the direction of large capacity, high pressure, low noise, high efficiency and high reliability. Continuously develop new air valves that operate under variable operating conditions to increase the service life of air valves; in product design, thermodynamics and kinetic theories are applied to predict the performance of the compressor under actual operating conditions through comprehensive simulation. Strengthen the mechanical and electrical integration of compressors and adopt computer automatic control to achieve optimized energy-saving operation and online operation.

In the power field, piston compressors currently occupy a major market. However, as people's requirements for use environment, energy consumption and environmental protection increase, screw type and scroll type air compressors have begun to occupy a certain market.

In the field of refrigeration and air conditioning, as a traditional refrigeration compressor, reciprocating refrigeration compressors are suitable for refrigeration systems with a wide range of refrigeration capacity. Although it is currently widely used, its market share is gradually decreasing.

At present, the main engine of the refrigerator refrigeration system (including small freezing and refrigerating devices) is still the previous compound compressor. After years of design improvement and technological progress, the efficiency of the reciprocating refrigerator compressor has been greatly improved. At the same time, the refrigerant substitution technology closely related to environmental protection has also made gratifying progress. Further improving the efficiency of the reciprocating refrigerator compressor and reducing system noise are its main development directions.

(1) Linear compressor The linear compressor is a kind of reciprocating compressor, because the linear motion of the motor can directly drive the reciprocating motion of the piston, thereby avoiding the complexity of the crank connecting rod mechanism and the resulting mechanical power consumption. The key technology of the linear compressor is the design of the compressor oil circuit system, the effective control of the motor's linear displacement point and the corresponding anti-collision technology.

(2) Swash plate compressor The swash plate compressor is also a modified structure of the reciprocating compressor, and is mainly used in vehicle air conditioning systems. After decades of development, the swash plate compressor has become a relatively mature model, occupying more than 70% of the market share of automotive air-conditioning compressors. But its efficiency is lower than that of a rotary compressor, and it is larger. Due to the maturity of technology and the further improvement of technology, swash plate compressors for automotive air conditioners will still maintain a certain market share in the foreseeable future, but it is an inevitable way to gradually replace them within a certain displacement range.

3. Rotary compressor

(1) Rolling rotor compressors At present, rolling rotor compressors are widely used in household air conditioners, and they also have certain applications in refrigerators. This type of compressor does not require a suction valve and is suitable for variable speed operation, thereby improving system performance through frequency conversion control. In order to ensure the performance of the high-power (motor output power 2.2kW (3P)) rolling-rotor compressor, my country developed a dual-rotor rolling-rotor compressor at the end of the last century, and it has been put on the market.

In the air conditioner below 2.2kW (3P), there is no better model to replace the rolling rotor compressor. Therefore, improving the efficiency of the compression process, reducing the noise, controlling the motor speed, and using new refrigerants such as R410A are related technical issues that are the research direction of the rolling rotor compressor.

(2) Sliding vane compressor, a type of rotary compressor, mainly used to provide compressed air, with a displacement of 0.3~3 m 3 /min, and a low market share. The rotary vane compressor is an improved structure of the vane compressor. Because of its good starting performance and small torque change during compression, it is mainly used in the air conditioning system of mini-cars and some small-displacement tool vehicles. High-speed dynamic characteristics is the main technical research direction of this compressor.

(3) Scroll compressors Scroll compressors have developed rapidly in the past ten years and constitute a new bright spot in the development of compressor technology. At present, scroll compressors have relative advantages in the field of cabinet air-conditioning. In the field of automotive air-conditioning, the refrigeration coefficient of scroll compressors has reached 2.0, showing strong competitiveness. The development of scroll compressors lies in expanding their cooling capacity range, further improving work efficiency, using alternative working fluids, and reducing manufacturing costs.

(4) Screw compressor The screw compressor has the characteristics of small size, light weight and convenient maintenance. It is a rapidly developing refrigeration compressor. On the one hand, the shape and structural design of the screw have been greatly improved. On the other hand, the introduction of special milling machines for screw rotors, especially grinders, has improved the machining accuracy and efficiency of these key parts, thereby effectively improving the performance of screw compressors. At present, screw compressors are mainly used in compressed air and medium-sized refrigeration heat pump air-conditioning systems. With the continuous improvement of the reliability of screw compressors, reciprocating compressors are gradually replaced in the medium refrigeration capacity range, occupying part of the centrifugal compressor market.