The technical status and development trend of air compressor

I. Introduction

Compressor is a machine used to increase gas pressure and transport gas, and belongs to a working machine that converts the power energy of the prime mover into gas pressure energy. It has a wide range of types and uses, and is known as "general machinery". At present, in addition to piston compressors, other types of compressors, such as centrifugal, twin-screw, rolling rotor and scroll types, have been effectively developed and utilized, providing users with a choice of models More possibilities. With the rapid economic development, my country's compressor design and manufacturing technology has also made great progress, and the technical level in some aspects has reached the international advanced level.

2. The status quo and development trend of compressor technology

1. Turbo compressor

In the petrochemical field, the current domestic centrifugal compressors cannot meet domestic needs 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 new issues in terms of large-scale production. There is no mature experience in designing and manufacturing these large-scale gas compressors in China. Centrifugal compressors need to develop to large capacity to meet the requirements of the continuous expansion of my country's petrochemical production scale. At the same time, with the development of new technologies, new gas seals, magnetic bearings and non-lubricated couplings, the development of turbo compressors The main trends are: continuous development of high-pressure and low-flow products; further research on the ternary flow theory, and apply it to the design of impellers and vane diffusers, so as to achieve high-efficiency units; reduce noise and adopt noise protection to improve Operating environment.

In the field of refrigeration and air-conditioning, the current turbo compressor still maintains an advantage in the range of large cooling capacity. The moving parts of the centrifugal compressor are few and simple, and the manufacturing precision is low, 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 the demand is small. In recent years, as large-scale infrastructure projects have been launched, centrifugal refrigeration compressors have become a focus of attention.

2. Reciprocating compressor

In the petrochemical field, reciprocating compressors are mainly developed in the direction of large capacity, high pressure, low noise, high efficiency, high reliability, etc.; continuous development of new valve operating under variable operating conditions to improve valve life; In design, thermodynamics and dynamics theories are applied to predict the performance of the compressor under actual working conditions through comprehensive simulation; the mechanical and electrical integration of the compressor is strengthened, and computer automatic control is adopted 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 have increased, screw and scroll 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 refrigeration system of refrigerators (including small freezing and cold storage devices) is still mainly reciprocating compressors. After years of design improvement and technological progress, the efficiency of reciprocating refrigerator compressors has been greatly improved. At the same time, gratifying progress has also been made in refrigerant substitution technology closely related to environmental protection. Further improving the efficiency of the reciprocating refrigerator compressor and reducing system noise are its main development directions.

(1) Linear (linear) compressor The linear compressor is a type of reciprocating compressor. Because the linear motion of the motor can directly drive the reciprocating motion of the piston, it avoids 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 linear displacement limit point, and the corresponding anti-collision technology.

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

3. Rotary compressor

(1) Rolling rotor compressors At present, rolling rotor compressors are widely used in household air conditioners, as well as in refrigerators. This type of compressor does not require a suction valve, making it suitable for variable speed operation, so that system performance can be improved through frequency conversion control. In order to ensure the performance of high-power (motor output power 2.2kW (3P)) rolling-rotor compressors, domestic research and development of dual-rotor rolling-rotor compressors began at the end of the last century, and they are now on the market.

Among the air conditioners below 2.2kW (3P), there is no better model that can replace the rolling rotor compressor. Therefore, improving the efficiency of the compression process, reducing noise, motor variable speed control, and related technical issues after the use of new refrigerants such as R410A are the research directions of rolling rotor compressors.

(2) Sliding vane compressors Sliding vane compressors are a type of rotary compressors. They are mainly used to provide compressed air. The displacement is generally 0.3 to 3 m 3 /min and the market share is low. The rotary vane compressor is a modified structure of the sliding vane compressor. Because of its good starting performance, the torque change during the compression process is not large. At present, it is mainly used for mini cars and some small displacement tool vehicles. Air Conditioning System. The dynamic characteristics at high speed 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 an absolute advantage in the field of cabinet air conditioners. 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 efficiency, using alternative working fluids and reducing manufacturing costs.

(4) Screw compressor The screw compressor has the characteristics of small size, light weight and easy maintenance. It is a type of refrigeration compressor that develops rapidly. On the one hand, the screw profile and structural design have made great progress. On the other hand, the introduction of special milling machines for screw rotors, especially grinders, has improved the machining accuracy and efficiency of this pair of key parts, and effectively improved the performance of the screw compressor. At present, screw compressors are mainly used in compressed air and medium-sized refrigeration heat pump air conditioning systems. Due to the continuous improvement of the working reliability of screw compressors, it has gradually replaced reciprocating compressors in the medium refrigeration capacity range, and occupied part of the centrifugal compressor market.

3. Preliminary market analysis of compressors

1. Gas compressor

Commonly used gas compressors include centrifugal gas compressors and reciprocating gas compressors. Over the years, my country's compressor manufacturing industry has overcome many difficulties and made major breakthroughs. However, my country's centrifugal compressors cannot meet domestic needs in terms of high technology, high parameters, high quality and special products. About 50% of the products need to be imported. Domestic small and medium-sized reciprocating compressors can basically meet the needs of the domestic petrochemical industry, but large-scale reciprocating compressors still cannot meet market needs, especially products with high technical content and special requirements. It is expected that the total demand for large and medium-sized compressors during the "Eleventh Five-Year Plan" period will increase more than the demand during the "Ninth Five-Year Plan" and "Tenth Five-Year Plan" period, especially for super-large and special process compressors. According to the current situation forecast, the compressor market in the next five years is basically stable and rising.

2. Household air-conditioning compressor

At present, the total production of room air conditioners in my country has surpassed that of the United States, ranking first in the world. In 2004, the apparent consumption of compressors (ie, sales + imports-exports) was 42 million units, while the output of air conditioners in the same period reached 47.46 million units. There was a gap of nearly 5.5 million units between the two. It is estimated that the supply of 6 million gapped air-conditioning compressors will be tight in 2005. However, with the expansion of air-conditioning compressor companies and the addition of refrigeration and air-conditioning companies, the production and sales volume of air-conditioning compressors in my country will reach 70 million units in 2006. By then, domestic air-conditioning compressors may be oversupply.

3. Automobile air-conditioning compressor

At present, although the types of automobile air-conditioning compressors are diverse, the output of swash plate compressors is still large, and the output of rotary compressors is small. The rotary compressor has fewer parts and high efficiency, which is an important development direction for automobile air-conditioning compressors. Rotary automobile air-conditioning compressors mainly include rotary vane compressors and scroll compressors. Rotary vane compressors are mainly based on Japan's Matsushita Co., Ltd. and Japan Seiko Seiki Co., Ltd., and Denso Corporation and Jack Sail also produce rotary vane compressors. Scroll compressors are mainly produced by Japan's Sanden Corporation, Mitsubishi Heavy Industries Corporation and Denso Corporation. Domestic companies have also begun to get involved in rotary automobile air-conditioning compressors.

Four, summary

With the development of my country's economy, my country's compressor design and manufacturing technology has also made great progress, and the technical level in some aspects has reached the international advanced level. However, there is still a certain gap with the international advanced level in some aspects. It is expected that the demand for compressors in my country during the "Eleventh Five-Year Plan" will increase significantly. This is both an opportunity and a challenge for us. It requires the joint efforts of compressor workers to promote the progress of compressor technology in my country.