Why most air compressor exhaust pressure is 8kg

The discharge pressure of most air compressors is set to 8kg (0.8MPa or 8bar), mainly because this pressure value is applicability, equipment compatibility, energy consumption and safety and other aspects to achieve a comprehensive balance, is the industrial application of the "golden pressure", the specific reasons are as follows:

1. for most pneumatic tools and equipment

1. tool design pressure matching
   the design working pressure of small and medium-sized pneumatic tools (such as pneumatic screwdrivers, spray guns, air nail guns, air picks, etc.) is usually in the range of 6-8kg. If the pressure of the air compressor exceeds 8kg, the internal parts of the tool (such as sealing ring, valve plate, spring) are easy to wear due to long-term high pressure, resulting in shortened life. For example, a pneumatic wrench can easily unscrew a rusty screw under a pressure of 8kg, but if the pressure rises to 10kg, its internal gears may be damaged due to excessive force.

2. Process Requirements Coverage
   8kg pressure can meet the needs of most industrial scenarios:

   • painting operation: The pressure of 5-7kg can ensure uniform paint mist and avoid excessive pressure causing excessive paint film or sagging.
   • Blow dust cleaning: 3-5kg pressure is enough to remove dust on the surface of precision parts, too high pressure may damage the components.
   • Tire inflation: Household tire pressure is usually 2.2-2.5kg, and the air compressor needs to be higher than this pressure to inflate, but 8kg is enough to inflate multiple tires at the same time without higher pressure.

Optimal Selection of 2. Energy Consumption and Efficiency

1. relationship between compression ratio and energy consumption
   the energy consumption of compressed air in an air compressor is directly related to the compression ratio (the ratio of exhaust pressure to intake pressure). To increase the pressure from 8kg to 10kg, the energy consumption needs to be increased by more than 20%, because stronger compression force is needed to press the air more tightly. The pressure of 8kg can meet most of the demand, and further pressure increase will significantly increase the operating cost.

2. Equipment load balancing
   under the pressure of 8kg, the air compressor has a moderate operating load, which can ensure the output efficiency without causing the motor to overheat or mechanical wear due to long-term high-pressure operation. For example, a 22kW air compressor has a displacement of 1.1m & sup3 under a pressure of 8kg;/min, if the pressure rises to 10kg, the displacement may drop to 0.9m & sup3;/min, but reduce the gas supply capacity.

3. safety and equipment life guarantee

1. design Standard for Piping and Gas Storage Tank
   industrial air compressor pipelines and gas storage tanks are usually designed at 8kg pressure. Overpressure may cause pipeline burst or gas storage tank safety valve action. For example, in order to pursue "more pumping", the small workshop adjusted the pressure to 12kg. As a result, the safety valve of the gas tank burst open, causing potential safety hazards.

2. long-term operation stability
   under the pressure of 8kg, the wear rate of the internal parts of the air compressor (such as cylinders, piston rings, bearings) is lower and the equipment life is longer. If the pressure is too high, the parts need to bear more stress, the failure rate increased significantly. For example, when the air nail gun is used under a pressure of 10kg, the firing pin is easy to bend and deform, causing the tool to be scrapped.

4. industry practices and standardization drive

1. medium and small air compressor mainstream configuration
   the default exhaust pressure of small and medium-sized air compressors (power 1-55kW) on the market is mostly 8kg, because this specification has formed an industry consensus, which is convenient for user selection and equipment matching. For example, the 22kW air compressor commonly used in auto repair shops has a 100l air tank with a pressure of 8kg, which can drive pneumatic wrenches, spray guns and other tools at the same time without additional adjustment.

2. International Standards and Certification Support
   most air compressor products have passed international certifications such as ISO and TÜV, and their design pressure must meet safety specifications. The pressure of 8kg not only meets the functional requirements, but also meets the safety standards of most countries and regions, reducing the risk of users.