Air Receiver Tanks for Air Compressors – Essential Knowledge You Must Know
The primary function of air receiver tanks in a compressed air system is to guarantee stable air supply. Inside the receiver, condensed water settles out. The tank stabilizes pressure fluctuations caused by unbalanced air consumption of pneumatic equipment and improves pressure stability for end users. It also reserves a volume of compressed air for emergency operation of pneumatic devices and control systems in case of air compressor failure.
Selection of Air Receiver Tanks
01 Pressure Selection
By withstand pressure, air receivers are classified into high-pressure, low-pressure and atmospheric-pressure types. The rated pressure of the selected air receiver shall be no less than the discharge pressure of the air compressor. For example, if the compressor operates at 8 bar, the receiver pressure rating must be ≥8 bar.
02 Volume Selection
The recommended volume of the air receiver ranges from 0.3 to 0.5 times the compressor free air delivery (FAD). A larger volume is preferred if site conditions permit, as it allows more air storage and better pre-water separation.
Example: If the air compressor delivers 1 m³/min at 8 bar, the receiver volume shall be between 0.3 m³ and 0.5 m³ (minimum 1/5 ~ 1/3 of compressor flow). A 0.2 m³ or 0.3 m³ tank is recommended for basic use. If future air demand will increase, a larger tank such as 0.5 m³, 0.6 m³ or 1 m³ can be adopted.
03 Material Selection
Based on material, receivers are categorized into carbon steel, low alloy steel and stainless steel receivers. They work together with air compressors, refrigerated air dryers and filters to form the compressed air station for industrial power supply.
Carbon steel and low alloy steel receivers are widely adopted in most industries. Low alloy steel receivers feature higher yield strength and toughness than carbon steel variants, with a relatively higher price.
Stainless steel receivers are mainly used in food processing, pharmaceutical, chemical, microelectronics and other industries requiring high comprehensive performance such as corrosion resistance and formability. Users can select according to actual working conditions.
Service Life of Air Receiver Tanks
Air receivers belong to special equipment. Manufacturers provide a recommended service life, generally 10 years. This does not mean the tank must be scrapped after 10 years. Tanks exceeding 10 years can remain in service if they pass annual inspection by market supervision authorities. However, tanks failing inspection within the 10-year service life cannot be used. Continued service is determined by official inspection reports.
Generally speaking, receivers with volume ≤1 m³ and design pressure ≤10 bar (including 10 bar) are classified as simple pressure vessels exempt from periodic inspection in China. Markings on nameplates and product certificates specify simple pressure vessels. No mandatory inspection or registration is required within the 7-year validity period, while auxiliary fittings shall be inspected in accordance with local regulatory requirements.
Receivers above 1 m³ and 10 bar must be submitted for inspection at local testing institutions. Operators need to obtain special equipment usage registration certificates, and installation must be performed by qualified contractors.
Difference Between Receiver Connection Types
Threaded Connection
Threaded connections feature screw threads and are suitable for small-diameter pipelines.
For instance, Rp1/2 stands for internal thread; Rp2 represents 2-inch internal thread. Common sizes include 1.5-inch and 2-inch threads.
Flanged Connection
Flanges are specified by DN (nominal diameter). DN50 refers to nominal diameter 50 mm. During assembly, pipelines are fixed to flange plates with gaskets fitted in between, then fastened by bolts. Flanged joints are easy to disassemble and provide better sealing than threaded connections, typically adopted for large diameters. Standard sizes include DN80, DN100, DN125 and DN150; non-standard customized sizes are also available.
Not all receiver models come with both threaded and flanged ports. The selection depends mainly on the interface size of the matched air compressor.
Inspection of Safety Valves on Air Receivers
The safety valve is a critical component of the air receiver and the whole compressed air system. Adjustment must be performed by professional operators, and pre-operation inspection is required following the steps below:
Cut off the air supply source;
Supply cooling water and start the unit for testing. Observe the pressure gauge. If the safety valve fails to open at the set pressure, adjust the bolt position repeatedly to achieve correct opening pressure. Carry out repeated tests and adjustments to ensure reliable valve opening.
Air receivers must be operated strictly in compliance with specifications. Safety valves and pressure gauges shall be properly installed and submitted for annual inspection (subject to local market supervision requirements). If continuous production cannot be interrupted, a spare set must be prepared; safety risks shall never be underestimated. Safety shall always be the top priority.
Operation Precautions for Air Receivers
Overpressure and overtemperature operation are strictly prohibited. Operators shall ensure the receiver runs under normal working conditions.
No maintenance work, hammering or impact on the tank shell is allowed. Do not walk on accumulated water around the equipment.
Open flames are forbidden around or inside the receiver. Flame lighting is prohibited for internal inspection.
For oil-injected compressors, compressed air must undergo oil and water removal before entering the receiver. The oil content, water vapor content, particle size and concentration of compressed air shall comply with Appendix A of GB/T 13277.1 Compressed Air for General Use — Part 1: Contaminant Purity Classes.
Due to contact between lubricating oil and air inside oil-injected compressors, excessive temperature may lead to carbon deposit spontaneous combustion and oil explosion risks (refer to GB 10892). The temperature of compressed air entering the receiver shall not exceed the tank design temperature. To avoid excessive discharge temperature, the compressor overtemperature shutdown device shall be inspected on schedule; heat transfer surfaces including filters, separators and coolers shall be cleaned regularly.
For oil-injected compressors, inspect all pipelines, receivers and fittings from the discharge port up to the point where air temperature drops to 80°C. All carbon deposits (including carbon buildup on compressor cylinder heads) must be thoroughly removed.
Operation and maintenance of air compressors and air receivers must comply with Safety Rules and Operating Procedures for Stationary Air Compressors, Safety Requirements for Positive Displacement Air Compressors, and Safety Requirements for Process Compressors.
Failure of operators to comply with the above requirements and warnings may lead to tank failure and severe explosion hazards. All users must bear these guidelines in mind!
Selection of Air Receiver Tanks
01 Pressure Selection
By withstand pressure, air receivers are classified into high-pressure, low-pressure and atmospheric-pressure types. The rated pressure of the selected air receiver shall be no less than the discharge pressure of the air compressor. For example, if the compressor operates at 8 bar, the receiver pressure rating must be ≥8 bar.
02 Volume Selection
The recommended volume of the air receiver ranges from 0.3 to 0.5 times the compressor free air delivery (FAD). A larger volume is preferred if site conditions permit, as it allows more air storage and better pre-water separation.
Example: If the air compressor delivers 1 m³/min at 8 bar, the receiver volume shall be between 0.3 m³ and 0.5 m³ (minimum 1/5 ~ 1/3 of compressor flow). A 0.2 m³ or 0.3 m³ tank is recommended for basic use. If future air demand will increase, a larger tank such as 0.5 m³, 0.6 m³ or 1 m³ can be adopted.
03 Material Selection
Based on material, receivers are categorized into carbon steel, low alloy steel and stainless steel receivers. They work together with air compressors, refrigerated air dryers and filters to form the compressed air station for industrial power supply.
Carbon steel and low alloy steel receivers are widely adopted in most industries. Low alloy steel receivers feature higher yield strength and toughness than carbon steel variants, with a relatively higher price.
Stainless steel receivers are mainly used in food processing, pharmaceutical, chemical, microelectronics and other industries requiring high comprehensive performance such as corrosion resistance and formability. Users can select according to actual working conditions.
Service Life of Air Receiver Tanks
Air receivers belong to special equipment. Manufacturers provide a recommended service life, generally 10 years. This does not mean the tank must be scrapped after 10 years. Tanks exceeding 10 years can remain in service if they pass annual inspection by market supervision authorities. However, tanks failing inspection within the 10-year service life cannot be used. Continued service is determined by official inspection reports.
Generally speaking, receivers with volume ≤1 m³ and design pressure ≤10 bar (including 10 bar) are classified as simple pressure vessels exempt from periodic inspection in China. Markings on nameplates and product certificates specify simple pressure vessels. No mandatory inspection or registration is required within the 7-year validity period, while auxiliary fittings shall be inspected in accordance with local regulatory requirements.
Receivers above 1 m³ and 10 bar must be submitted for inspection at local testing institutions. Operators need to obtain special equipment usage registration certificates, and installation must be performed by qualified contractors.
Difference Between Receiver Connection Types
Threaded Connection
Threaded connections feature screw threads and are suitable for small-diameter pipelines.
For instance, Rp1/2 stands for internal thread; Rp2 represents 2-inch internal thread. Common sizes include 1.5-inch and 2-inch threads.
Flanged Connection
Flanges are specified by DN (nominal diameter). DN50 refers to nominal diameter 50 mm. During assembly, pipelines are fixed to flange plates with gaskets fitted in between, then fastened by bolts. Flanged joints are easy to disassemble and provide better sealing than threaded connections, typically adopted for large diameters. Standard sizes include DN80, DN100, DN125 and DN150; non-standard customized sizes are also available.
Not all receiver models come with both threaded and flanged ports. The selection depends mainly on the interface size of the matched air compressor.
Inspection of Safety Valves on Air Receivers
The safety valve is a critical component of the air receiver and the whole compressed air system. Adjustment must be performed by professional operators, and pre-operation inspection is required following the steps below:
Cut off the air supply source;
Supply cooling water and start the unit for testing. Observe the pressure gauge. If the safety valve fails to open at the set pressure, adjust the bolt position repeatedly to achieve correct opening pressure. Carry out repeated tests and adjustments to ensure reliable valve opening.
Air receivers must be operated strictly in compliance with specifications. Safety valves and pressure gauges shall be properly installed and submitted for annual inspection (subject to local market supervision requirements). If continuous production cannot be interrupted, a spare set must be prepared; safety risks shall never be underestimated. Safety shall always be the top priority.
Operation Precautions for Air Receivers
Overpressure and overtemperature operation are strictly prohibited. Operators shall ensure the receiver runs under normal working conditions.
No maintenance work, hammering or impact on the tank shell is allowed. Do not walk on accumulated water around the equipment.
Open flames are forbidden around or inside the receiver. Flame lighting is prohibited for internal inspection.
For oil-injected compressors, compressed air must undergo oil and water removal before entering the receiver. The oil content, water vapor content, particle size and concentration of compressed air shall comply with Appendix A of GB/T 13277.1 Compressed Air for General Use — Part 1: Contaminant Purity Classes.
Due to contact between lubricating oil and air inside oil-injected compressors, excessive temperature may lead to carbon deposit spontaneous combustion and oil explosion risks (refer to GB 10892). The temperature of compressed air entering the receiver shall not exceed the tank design temperature. To avoid excessive discharge temperature, the compressor overtemperature shutdown device shall be inspected on schedule; heat transfer surfaces including filters, separators and coolers shall be cleaned regularly.
For oil-injected compressors, inspect all pipelines, receivers and fittings from the discharge port up to the point where air temperature drops to 80°C. All carbon deposits (including carbon buildup on compressor cylinder heads) must be thoroughly removed.
Operation and maintenance of air compressors and air receivers must comply with Safety Rules and Operating Procedures for Stationary Air Compressors, Safety Requirements for Positive Displacement Air Compressors, and Safety Requirements for Process Compressors.
Failure of operators to comply with the above requirements and warnings may lead to tank failure and severe explosion hazards. All users must bear these guidelines in mind!
