Innovation and Development of Single Screw Compressor


Times are changing, society is progressing, and 2016 is about to pass in a blink of an eye. Under the environment of weak global economic growth and slowing domestic economic growth, the total demand for the air compressor industry is also gradually decreasing. Under the application of assembly line and high-efficiency automated production equipment, conventional products can easily increase production capacity. In this case, the price of conventional compressors is getting worse day by day, and the price is falling again and again. There is no minimum but lower. In contrast, the prices of some high-tech and high-difficulty compressors, such as centrifuges, oil-free scroll compressors, medium and high-pressure oil-free piston compressors, and diaphragm compressors, have not fallen. Various phenomena show that only products with high technological content can have vitality, gain profits, and be in a favorable position in the competition.

As a main type of compressor, the single screw compressor has certain advantages in terms of structure and principle, such as many times of compression and exhaust per revolution, balanced bearing force, long bearing life, etc. Of course, there are also some disadvantages. , such as no mature processing machine tools, complex structure, large volume, high host production cost, large number of parts and so on. In a period of time, the market share of oil-injected single-screw air compressors was very high. Several manufacturers achieved annual sales of more than one hundred million or even hundreds of millions, and they had a tendency to occupy half of the entire compressor industry. Later, it was shrinking year by year. Until today, the market share of oil-injected single-screw air compressors has been very small. I think everyone has experienced this process. There must be consequences. What causes the market for oil-injected single-screw compressors to decline year by year? It is the result of the selection of the fittest in the market, and the result of the decline in the cost performance of oil-injected single-screw products compared to twin-screw air compressors. I think there are mainly the following aspects:

1. When twin-screw production enterprises introduce foreign rotor grinders and precision machining centers, mass-produce twin-screw main engines, the performance and reliability of twin-screw machines are greatly improved, and production costs are rapidly reduced, single-screw production enterprises have no major breakthrough in the efficiency and precision of processing machine tools. There is no expansion in production capacity, which directly leads to a decline in cost performance and widens the cost-price gap between twin-screw machines and single-screw machines.
2.The star wheel wear problem, which has long plagued the quality of the single screw, has not been completely solved, and many end users have experienced a decline in gas production after a long time of use. The single-screw compressor can achieve no wear when all aspects such as the star wheel profile, the machining accuracy of the parts, and the assembly accuracy of the main engine are in place. Our two-stage compression 4.0Mpa model has been used for many years in a large area, and it has been proved that the single-screw star wheel can be worn without wear. I think that the single screw air compressor should be perfected from the following points:  a reasonable profile is the basis for ensuring the long life of the star wheel.  The machining accuracy of the parts directly affects the service life of the star wheel. The selection and service life of the bearing directly affect the life of the star wheel.  The assembly accuracy of the host directly affects the service life of the star wheel. ⑤There are many imperfections in the control system of the single screw air compressor, and it is necessary to design unique special valve parts and mechanisms to ensure stability and reliability.
A product has no advantage in price and cost, and in the case of no advantage in performance, it will inevitably lead to less and less market share.
In today's world, resource and environmental issues are common challenges faced by mankind, and green and low-carbon development is becoming an international development trend. Especially in the context of coping with the international financial crisis and climate change, promoting green growth and implementing the Green New Deal are the common choices of major economies around the world. Developing a green economy and seizing the commanding heights of future global economic competition has become an important national strategy. Especially since the beginning of the new century, concepts such as green economy, low-carbon economy and circular economy have been put forward and put into practice. Innovation and change are always accompanied by social development. With the improvement of society's awareness of environmental protection and energy saving, the society's requirements for compressor energy consumption are getting higher and higher. The single-screw structure bearing has good force balance, high volumetric efficiency, and can use water lubrication for work, etc. These advantages are unmatched by twin-screw compressors. I personally think that how to maximize these advantages is a problem that single-screw manufacturers must think about.
 Due to the relatively balanced force on the bearing of the single-screw compressor structure, water can be used to replace expensive and environmentally polluting lubricating oil for lubrication and cooling, which greatly reduces the exhaust temperature and the operating temperature of the unit, and realizes isothermal compression. In the field of machinery, water lubrication has great advantages compared with dry oil-free compression, such as high efficiency, large gas production at the same power (specific power is 10%-20% lower), ultra-low maintenance costs, low operating temperature of the unit, no use of any lubricating oil. And because its one-stage compression achieves the effect of dry-grade oil-free two-stage compression, the manufacturing cost is low. When CMN water-lubricated oil-free air compressors gained a certain market share and received high evaluations from users, many single-screw manufacturers carried out the production of water-lubricated compressors, which is surely a good thing. The beginning of the competition of foreign brands of oil-free machines is the beginning of product replacement. However, many manufacturers which have major problems with their manufacturing quality, are eager for quick success in their operations, and adopt ultra-low price sales which leads to the phenomenon that many users are not satisfied with their use. Most of the customers who buy oil-free machines are more standardized, and they pay more attention to the stability of product use. Product quality is always the basis for development and survival. Due to the quick success of several manufacturers, bad products have entered the market, which will seriously affect the development of the water-lubricated oil-free machine industry. I hereby appeal to everyone not to introduce low-quality products into the market, to cherish and cultivate the water-lubricated oil-free machine market together, and not to spoil a good-end product and make it a product that customers do not trust. Our company is responsible for drafting and formulating the national industry standard JB/T11882-2014 "Water-injection Single-Screw Air Compressor for General Use", which was issued and implemented by the Ministry of Industry and Information Technology in October 2014. We hope that we can strictly implement the standard and improve product quality together. Products without quality do not have the conditions for development.
It is also due to the fact that the bearing force on the single-screw compressor is relatively balanced, and it will have incomparable advantages over the twin-screw compressor when used for medium and high pressure compression. CMN two-stage compression medium pressure single screw oil injection compressor was launched to the market in 2011. Nowadays, various medium pressure machines with pressure ranges from 2.0Mpa to 4.0Mpa and powers from 18.5kW to 250kW are widely used in various fields such as bottle blowing, pressure testing, aviation, drilling, and mining, and are favored by users. Especially in terms of energy saving, the energy saving effect is as high as 30% compared with the piston type medium pressure compressor. Single screw is also a good development direction in the field of medium pressure compression. The industry standard JB/T12565-2015 "Medium Pressure Single Screw Air Compressor" drafted by our company (Zhejiang Jieneng Compression Equipment Co., Ltd.) was promulgated and implemented by the Ministry of Industry and Information Technology of the People's Republic of China on October 10, 2015, providing Everyone's work in this field with the basis and guarantee. 
In the field of oil-free medium pressure compressors, only a few foreign piston compressor manufacturers currently occupy more than 90% of the world's market share. The two-stage compression medium-pressure oil-free single-screw air compressor of CMN has completed the type test last year and has been put into market application.

Single-screw compressors have many advantages that twin-screw compressors cannot match, and of course there are some disadvantages. We must take advantage of strengths and avoid weaknesses, and give full play to the excellent characteristics of single-screw models. In the field of water-lubricated oil-free and medium-pressure compression, we will do a good job of single-screw, make our own characteristics, and make them energy-saving, reliable and efficient high-quality products that users like. CMN is willing to communicate, discuss with the majority of single-screw manufacturers, jointly make products, jointly cultivate the market, and jointly bring low-energy consumption, high reliability, and easy-to-use single-screw products to the market.