Overview of Screw Refrigeration Compressor Technology
Screw compressors, also known as screw compressors, are divided into single screw compressors and twin screw compressors. The single screw compressor was developed by Sinn, France in the 1970s. Because of its more reasonable structure, it was quickly applied to the national defense field and protected by developing countries. The technology has always been relatively independent. The twin-screw compressor was first proposed by the German H. Krigar in 1878. It was not until A. Lysholm of the Royal Institute of Technology in Sweden that the screw compressor SRM technology was established in 1934, and it began to be applied in industry and achieved rapid development. In this issue of okmarts.com, we will give you a comprehensive understanding of the principle, characteristics, history and prospects of screw compressors.
Brief introduction of screw refrigeration compressor:
Screw refrigeration compressor compressor is also called screw compressor.
In the 1950s, oil-injected screw-type refrigeration compressors were used in refrigeration devices. Because of their simple structure and few wearing parts, they can have low exhaust temperature under large pressure differences or pressure ratios. The refrigerant contains a large amount of lubricating oil (often referred to as the wet stroke), which is insensitive and has good air flow regulation. It quickly occupied the use range of large-capacity reciprocating compressors, and continued to extend to the medium-capacity range. It is widely used in refrigeration equipment such as freezing, refrigeration, air conditioning and chemical technology. The screw heat pump with it as the main engine has been used in heating and air conditioning since the early 1970s. There are air heat source type, water heat pump type, heat recovery type, ice storage type and so on. In industry, in order to save energy, screw heat pumps are also used for heat recovery.
[Special topic] Overview and development of screw-type refrigeration compressor technology
Representative enterprise/model
Bitzer
Since entering the market in 1983, Bitzer screw compressors have achieved success worldwide. The compact shape of BITZER screw compressors, general-sized motors and bearings, and the use of a patented rotor production process to achieve the highest profile accuracy are widely praised. In addition, the use of economizers for efficient operation, sturdy design, and fewer moving parts is also a commendable place for BITZER screw compressors. Since it is not driven by gears, the rotating parts have low mass and low operating noise.
Compact screw compressor for Bitzer R134a
【Special topic】Summarization and development of screw type refrigeration compressor technology
The new generation of R134a dedicated compact screw compressor further optimizes the compressor design, improves the compressor efficiency at part load, and increases the compressor's seasonal energy efficiency ratio by more than 15%. The new design inherits the high-quality and high-reliability design concept of the previous generation of compressors, thereby reducing the cost of ownership of the compressor throughout its life cycle.
Bitzer inverter air conditioner screw compressor
【Special topic】Summarization and development of screw type refrigeration compressor technology
Bitzer closely followed the market's energy-saving requirements and took the lead in introducing screw compressors for inverter air conditioners. This series of compressors can adjust the cooling output at any time according to the change of the system load, so that the compressor has been running at high efficiency. Because the compressor adopts frequency conversion control, the compressor's safe operating range parameters are preset in the inverter control program. By adjusting the speed, the compressor is always running within the safe operating range, and the reliability of the compressor has been further improved. .
Dunham Bush
In 1894, Dunham Bush Company was founded in Hartford, Connecticut, USA. After 120 years of development, Dunham Bush’s products and services have now covered the fields of HVAC, industrial refrigeration, fluid cooling and other equipment manufacturing, as well as system integration control of corresponding products. The company still has technologies including fully enclosed screw technology. 48 world patents, ranking top of the world's screw compressor technology. In 1995, Dunhambush China set up a R&D center and manufacturing plant in Yantai. The product line includes compressors, large chillers, heat pump units, air-side heat exchange products, small commercial air conditioning units, cryogenic refrigeration units, cooling towers, etc.; fast and rapid The pre-sales technical support and after-sales service network covers 46 major cities and regions in China.
Fully enclosed screw compressor
【Special topic】Summarization and development of screw type refrigeration compressor technology
Performance characteristics:
The compressor adopts a vertical fully enclosed structure design to prevent oil and gas leakage.
The double-layer shell has good strength and lower noise
Vertical rotor design, small rotor load, reliable operation, design life up to 100,000 hours
Built-in two-stage high-efficiency oil separation, with oil separation efficiency as high as 99.7%
The whole series realize stepless energy adjustment, higher partial load efficiency, and more stable and efficient operation.
Hanbell Precision Machinery
Specializing in the research and development, production, sales and after-sales service of screw compressors. The main products are screw refrigeration compressors and screw air compressors. Among them, screw refrigeration compressors are mainly used in large-scale commercial central air conditioners in the refrigeration industry. Equipment and refrigeration equipment, screw air compressors are mainly used in the field of industrial automation. After years of development, it has become one of the most powerful compressor manufacturers in mainland China, integrating compressor design and development, manufacturing, quality assurance, sales and service systems.
Single two-stage screw refrigeration compressor
【Special topic】Summarization and development of screw type refrigeration compressor technology
Elaborate research and development
HANBELL single-machine two-stage screw refrigeration compressor is a special low-temperature compressor that has been carefully developed in recent years by integrating low-temperature market application experience and customer needs. And won the "Innovative Product" finalist award at the 25th China Refrigeration Exhibition in 2014.
Low temperature and high efficiency
The lowest operating temperature is -65 degrees Celsius (R404a refrigerant). Under conditions below -30 degrees Celsius, compared to a single-stage compression system with an economizer, the COP is increased by 30%; compared to similar single-stage two-stage products in the industry, the performance is increased by more than 5%.
Complete varieties and specifications
It can provide single-unit twin-stage screw refrigeration compressors of 50HP\75HP\100HP\120HP\140HP\160HP, and can use different types of refrigerants (including R717).
Simple system
The use of a single-machine two-stage screw compressor instead of a two-machine matching system not only saves the complicated pipeline installation, but also effectively reduces customer costs, but also saves the installation cycle. The design of fluorine circuit and oil circuit on both sides of the pipe is more concise and beautiful.
Modular design
The high and low pressure stage has a 1:2 or 1:3 displacement ratio combination, which can meet various applications such as low temperature refrigeration, high temperature heat pump, and low temperature air source heat pump. And with semi-closed and open dual-purpose design, the motor power can be configured according to working conditions.
Product configuration
Built-in exhaust muffler and suction filter; built-in motor PTC and PT100 temperature protection detection.
Standard accessories
Suction filter, suction check valve, economizer check valve, exhaust check valve.
Carrier
Carrier is the world’s largest supplier of refrigeration and air-conditioning equipment and systems, with branches in 171 countries and regions. With advanced technology and high-quality services, it is in a leading position in the industry. Since 1983, Carrier has started to use Totalline in the United States. Registered trademark of the parts business. Today, Totalline has become the world's high-quality brand of air-conditioning and refrigeration accessories, and has established a global specialty store distribution network to supply a full line of refrigeration accessories and products to meet the needs of the industry in installation, repair and maintenance projects The demand.
30XW-V frequency conversion screw chiller and heat pump
【Special topic】Summarization and development of screw type refrigeration compressor technology
IPLV up to 10
Cooling capacity: 571-1634kW;
Heating capacity: 623-1775 KW
The 30XW-V variable frequency screw chiller and heat pump adopt GreedspeedTM variable frequency drive technology, which can achieve precise matching between cooling and heating and building load changes, and achieve efficient operation throughout the season. The heat exchanger has a vertical design, compact structure, and can pass through standard door frames. The color touch screen Touch Pilot Control intelligent control system is adopted to comprehensively improve the operating stability and economy of the unit. 30XW-V is certified by the American Air Conditioning, Heating and Refrigeration Industry Association 550/590.
30XAV frequency conversion air-cooled screw chiller
【Special topic】Summarization and development of screw type refrigeration compressor technology
Cooling capacity: 336-1476kW
The 30XAV series air-cooled unit relies on the mature design platform of the Thunder series, adopts Greenspeed® variable frequency drive technology, and is equipped with a new Touch Pilot control platform. It intelligently and accurately responds to changes in building load, achieves efficient operation throughout the season, greatly reduces equipment operating costs, and provides customers with a green building The preferred solution for certification. It is widely used in comfortable air-conditioned buildings with significant load fluctuations, such as hotels, comprehensive commercial plazas, etc. It can also be used in places with relatively stable building loads such as data centers and process cooling in cold climates. The investment payback period is generally less than 2 Years, it is the preferred solution for engineers, designers and building owners who pursue excellent energy efficiency and operational performance.
Yantai ice wheel
Founded in 1956, Yantai Binglun Group focuses on the R&D and manufacturing of refrigeration and air-conditioning equipment and gas compression equipment, integration of refrigeration and air-conditioning application systems, refrigeration and air-conditioning energy-saving services, and complete engineering services. It is a leading enterprise in China's national refrigeration and air-conditioning industry. Screw refrigeration compressor units are widely used in food, beverages, refrigeration, low temperature logistics, new energy, petrochemicals, hydropower, coal, pharmaceuticals, artificial refrigeration environments and other fields. It is the best model in the industrial and commercial refrigeration field.
Yantai Binglun LG series screw refrigeration compressor unit
[Special topic] Overview and development of screw-type refrigeration compressor technology
LG series screw refrigeration compressor unit specifications: distinguished by rotor diameter and rotor lead, from LG12M to LG40L, a total of 14 specifications, displacement from 285m3/h to 7539m3/h, divided into water-cooled oil cooler series and liquid The cold oil cooler series, with adjustable content-to-volume ratio, flexible and diverse control methods, and perfect model spectrum, can meet the different cooling needs of users in various industries.
The working principle of screw refrigeration compressor
The screw compressor cylinder is equipped with a pair of intermeshing spiral female and male rotors. Both rotors have several concave teeth, and the two rotate in opposite directions. The gap between the rotors and between the casing and the rotor is only 5-10 wires. The main rotor (also known as male rotor or convex rotor) is driven by an engine or motor (mostly driven by an electric motor), and the other rotor (also known as Female rotor or female rotor) is driven by the oil film formed by the main rotor through oil injection, or driven by the synchronous gears at the main rotor end and the concave rotor end. So there is no metal contact in the drive (in theory).
The length and diameter of the rotor determine the compressor displacement (flow) and discharge pressure. The longer the rotor, the higher the pressure; the larger the rotor diameter, the greater the flow.
【Special topic】Summarization and development of screw type refrigeration compressor technology
The groove of the spiral rotor is filled with gas when passing through the suction port. When the rotor rotates, the rotor groove is closed by the casing wall to form a compression chamber. When the rotor groove is closed, the lubricating oil is sprayed into the compression chamber to seal. Cooling and lubrication. When the rotor rotates and compresses the lubricant + gas (referred to as the oil-air mixture), the volume of the compression chamber decreases, and the oil-air mixture is compressed toward the exhaust port. When the compression chamber passes through the exhaust port, the oil and gas mixture is discharged from the compressor, completing a suction-compression-discharge process.
Each rotor of the screw machine is supported by an anti-friction bearing, and the bearing is fixed by an end cover near the end of the rotating shaft. The intake end is supported by a roller bearing, and the exhaust end is supported by an abutting cone roller bearing, which is usually a bearing at the exhaust end to position the rotor, that is, a thrust bearing, which resists axial thrust and bears radial load. Provide the necessary minimum clearance for axial operation.
The working cycle can be divided into three processes: suction, compression and exhaust. As the rotor rotates, each pair of mutually meshing teeth completes the same work cycle one after another.
Disadvantages of screw refrigeration compressors:
1. High cost. Because the tooth surface of the rotor of the screw compressor is a spatial curved surface, it is necessary to use special tools for processing on expensive special equipment. In addition, there are higher requirements for the machining accuracy of the screw compressor cylinder.
2. Cannot be used in high pressure occasions. Due to the limitations of rotor stiffness and bearing life, screw compressors can only be used in the middle and low pressure range, and the discharge pressure generally does not exceed 3MPa.
3.Cannot be used in micro occasions. The screw compressor relies on the gap sealing gas. Generally, the screw compressor has superior performance only when the volume flow is greater than 0.2m3/min.
Comparison of single and double rod screw refrigeration compressors:
The development history of screw refrigeration compressors
1. In 1878, Heinrich Krigar proposed the principle of screw compressor and applied for a patent in Germany.
2. In 1935, Alf Lysholm (the chief engineer of turbo compressor manufacturer Ljungstroms Angturbin AB) improved the molding line, proposed a method for precise rotor manufacturing, and applied for a patent (5-4 teeth).
3. In 1951, Ljungstroms Angturbin AB was renamed Svenska Rotor Maskiner AB, the famous SRM company.
4. In the 1960s, SRM company launched SRMA model line, ATLAS company launched ATLAS model line. Developed from symmetrical tooth profile to asymmetrical tooth profile, the volumetric efficiency is increased by more than ten percent. my country began to develop screw air compressors in 1965.
5. In the 1970s, the German screw air compressor manufacturer Guthoffnungshutte, the GHH company, launched the GHH line. (Currently acquired by I-R in the United States, and joined forces) SRM launched the SRMD line.
During the product promotion stage in the 1980s, in-depth research on the system began. In 1985, some compressor factories in my country introduced 2AC and 5AC screw milling machines from Holroyd Company of the United Kingdom to form mass production.
After the 1990s, the machining accuracy was further improved. (CNC milling -> CNC grinding).
Prospects for screw refrigeration compressors
(1) Improve the independent R&D and design capabilities of screw host technology
The screw host is the core component of the screw compressor, and its performance will directly affect the performance of the whole machine. At present, the independent R&D and design capabilities of domestic companies are not strong enough. Only a few companies can independently produce screw compressors. Most of the other screw compressor companies do not have the ability to produce the host, and mainly rely on outsourcing to complete the complete machine. Assembly production. Therefore, comprehensively improving the independent R&D and design capabilities of screw host technology will be a major trend in the development of domestic industry technology.
(2) Development trend of fine processing
In the production process of the screw main engine, the requirements for the profile meshing accuracy and surface roughness of the screw main engine rotor are very high. With the in-depth development of the industry, the R&D and design capabilities of the screw rotor and its profile have been continuously improved. Traditional milling, cutting, and grinding have gradually been unable to meet the accuracy design requirements of the product, and it is difficult to ensure the service life and performance of the product to achieve the expected results. Therefore, this puts forward higher requirements on the processing and manufacturing capabilities and processing methods of the industry.
With the widespread application of modern information technology, precision processing equipment is gradually being applied to the manufacturing process of screw compressors. Traditional milling, cutting, and grinding technologies are gradually developing in the direction of fine milling and fine grinding to improve products. The processing accuracy. However, since most of these precision processing equipment are currently imported from abroad, the procurement cost is relatively high, and there are still fewer companies in the industry. Therefore, with the rapid growth of domestic precision processing equipment, driven by the demand for refined processing in the industry , Refined processing is bound to become an important technological development trend in the screw compressor industry in the future.
(3) Development trend of energy saving and emission reduction technology
With the development trend of global energy conservation and environmental protection, my country has begun to enter the era of "low carbon and energy saving". The essence of "low carbon and energy saving" is the efficient use of energy and the development and utilization of new energy. At present, the application and development of energy-saving and emission-reduction technologies have become the guiding direction of my country's industrial development. As a basic industry of my country's industrial industry, screw compressors have also been included in the field of energy-saving equipment.
On October 26, 2009, the National Development and Reform Commission, the General Administration of Quality Supervision, Inspection and Quarantine, and the State Certification and Accreditation Administration jointly issued the "Product Catalogue of the People’s Republic of China Implementing Energy Efficiency Labels (Fifth Batch)" (National Development and Reform Commission Announcement No. 17, 2009) ), the screw air compressor is included in the energy efficiency labeling system. Since March 1, 2010, related products produced, sold and imported in mainland China shall be marked with energy efficiency labels, and sellers shall not sell energy efficiency labels that should be marked but not marked The product.
Therefore, further improving the energy-saving and consumption-reducing effects of screw compressors, improving product energy efficiency levels, further expanding the scope of application of process gas of screw compressors, and strengthening the application of screw compressors in the field of energy saving and emission reduction will also be an important part of the industry’s future technology research and development. trend.
(4) Continue to develop and promote screw compressors for technological processes
The screw compressor used in the process flow has strong environmental applicability, is not sensitive to dust and liquid gas, and has no pollution to the conveyed gas. At the same time, the energy-saving effect is significantly better than other traditional compressors. Therefore, it is suitable for combustible gas and other water-containing, The recycling and utilization of impurity gas will fully highlight its performance superiority and importance of status. At present, China's screw compressors have achieved a substantial increase in variety, specifications and output in the field of aerodynamics, but there are still fewer applications in the field of process applications, such as coal bed methane, petroleum-associated gas, natural gas, biogas, and industrial tail gas. The development and application of combustible gas extraction, transportation and liquefaction processes, especially screw compressor models for large flow and medium and high exhaust pressure process processes, are still in their infancy. At present, the state has included coalbed methane, natural gas collection, liquefaction transportation, oil-associated gas, flare gas, and petrochemical tail gas recovery and utilization into key investment and construction projects, which provides a huge development opportunity for screw compressors for technological processes.
Advantages of screw refrigeration compressor:
1. High reliability. The screw compressor has few parts and no wearing parts, so it runs reliably and has a long life. The interval between overhauls can reach 40,000 to 80,000 hours;
2. Convenient operation and maintenance;
3. Good power balance. Particularly suitable for use as a mobile compressor, with small size, light weight and less floor space;
4. Strong adaptability. The screw compressor has the characteristics of forced air delivery, the volume flow is almost not affected by the exhaust pressure, and it can maintain high efficiency in a wide range. It is suitable for a variety of working fluids without any changes to the compressor structure. .
4.Multiphase mixed transmission. There is actually a gap between the tooth surfaces of the rotor of the screw compressor, so it can withstand liquid impact, and can transport liquid-containing gas, dust-containing gas, and easily polymerized gas.
Disadvantages of screw refrigeration compressors:
1. High cost. Because the tooth surface of the rotor of the screw compressor is a spatial curved surface, it is necessary to use special tools for processing on expensive special equipment. In addition, there are higher requirements for the machining accuracy of the screw compressor cylinder.
2. Cannot be used in high pressure occasions. Due to the limitations of rotor stiffness and bearing life, screw compressors can only be used in the middle and low pressure range, and the discharge pressure generally does not exceed 3MPa.
3.Cannot be used in micro occasions. The screw compressor relies on the gap sealing gas. Generally, the screw compressor has superior performance only when the volume flow is greater than 0.2m3/min.
Comparison of single and double rod screw refrigeration compressors:
The development history of screw refrigeration compressors
1. In 1878, Heinrich Krigar proposed the principle of screw compressor and applied for a patent in Germany.
2. In 1935, Alf Lysholm (the chief engineer of turbo compressor manufacturer Ljungstroms Angturbin AB) improved the molding line, proposed a method for precise rotor manufacturing, and applied for a patent (5-4 teeth).
3. In 1951, Ljungstroms Angturbin AB was renamed Svenska Rotor Maskiner AB, the famous SRM company.
4. In the 1960s, SRM company launched SRMA model line, ATLAS company launched ATLAS model line. Developed from symmetrical tooth profile to asymmetrical tooth profile, the volumetric efficiency is increased by more than ten percent. my country began to develop screw air compressors in 1965.
5. In the 1970s, the German screw air compressor manufacturer Guthoffnungshutte, the GHH company, launched the GHH line. (Currently acquired by I-R in the United States, and joined forces) SRM launched the SRMD line.
During the product promotion stage in the 1980s, in-depth research on the system began. In 1985, some compressor factories in my country introduced 2AC and 5AC screw milling machines from Holroyd Company of the United Kingdom to form mass production.
After the 1990s, the machining accuracy was further improved. (CNC milling -> CNC grinding).
Prospects for screw refrigeration compressors
(1) Improve the independent R&D and design capabilities of screw host technology
The screw host is the core component of the screw compressor, and its performance will directly affect the performance of the whole machine. At present, the independent R&D and design capabilities of domestic companies are not strong enough. Only a few companies can independently produce screw compressors. Most of the other screw compressor companies do not have the ability to produce the host, and mainly rely on outsourcing to complete the complete machine. Assembly production. Therefore, comprehensively improving the independent R&D and design capabilities of screw host technology will be a major trend in the development of domestic industry technology.
(2) Development trend of fine processing
In the production process of the screw main engine, the requirements for the profile meshing accuracy and surface roughness of the screw main engine rotor are very high. With the in-depth development of the industry, the R&D and design capabilities of the screw rotor and its profile have been continuously improved. Traditional milling, cutting, and grinding have gradually been unable to meet the accuracy design requirements of the product, and it is difficult to ensure the service life and performance of the product to achieve the expected results. Therefore, this puts forward higher requirements on the processing and manufacturing capabilities and processing methods of the industry.
With the widespread application of modern information technology, precision processing equipment is gradually being applied to the manufacturing process of screw compressors. Traditional milling, cutting, and grinding technologies are gradually developing in the direction of fine milling and fine grinding to improve products. The processing accuracy. However, since most of these precision processing equipment are currently imported from abroad, the procurement cost is relatively high, and there are still fewer companies in the industry. Therefore, with the rapid growth of domestic precision processing equipment, driven by the demand for refined processing in the industry , Refined processing is bound to become an important technological development trend in the screw compressor industry in the future.
(3) Development trend of energy saving and emission reduction technology
With the development trend of q* energy saving and environmental protection, my country has begun to enter the era of "low carbon and energy saving". The essence of "low carbon and energy saving" is the efficient use of energy and the development and utilization of new energy. At present, the application and development of energy-saving and emission-reduction technologies have become the guiding direction of my country's industrial development. As a basic industry of my country's industrial industry, screw compressors have also been included in the field of energy-saving equipment.
On October 26, 2009, the National Development and Reform Commission, the General Administration of Quality Supervision, Inspection and Quarantine, and the State Certification and Accreditation Administration jointly issued the "Product Catalogue of the People’s Republic of China Implementing Energy Efficiency Labels (Fifth Batch)" (National Development and Reform Commission Announcement No. 17, 2009) ), the screw air compressor is included in the energy efficiency labeling system. Since March 1, 2010, related products produced, sold and imported in mainland China shall be marked with energy efficiency labels, and sellers shall not sell energy efficiency labels that should be marked but not marked The product.
Therefore, further improving the energy-saving and consumption-reducing effects of screw compressors, improving product energy efficiency levels, further expanding the scope of application of process gas of screw compressors, and strengthening the application of screw compressors in the field of energy saving and emission reduction will also be an important part of the industry’s future technology research and development. trend.
(4) Continue to de
