Tag: 压缩空气

What is “the gas supply is not less than 0. 2m³ @ 0.3MPa /min ”?

This parameter is the key performance index of compressed air system or pneumatic equipment, indicating that the pressure is0.3 MPa (MPa)stable output air volume per unit timeno less than 0.2 cubic meters (m³), the time unit isper minute (min).

Standard writing forms description

it is recommended to adopt internationally accepted and unambiguous engineering expressions:

• numerical unit working condition, use the @ symbol to connect pressure conditions (industry practice, non-mathematical multiplication sign);
• unified use of pressure unitsMPa(Instead of kgf/cm² or bar), avoid conversion errors;
• for unit volumem³, Time Unitmin, slash “/” cannot be omitted;
• “Not less than” should be explicitly written≥0.2 m³/min @ 0.3 MPa(More in line with technical documentation specifications).

Common miswriting and precautions

❌Error example:
•” 0.2m3/min @ 0.3mpa “(Case is not standard, space is missing, unit abbreviation is incorrect)
• 0.2 cubic meters/minute @ 0.3 MPa (mixed Chinese and symbols, not applicable to the technical tender)
✅Correct example:
≥0.2 m³/min @ 0.3 MPa

0.3 MPa

≥0.2 m³/min
airflow direction →

What Is a Micro-Oil Air Compressor?

A micro-oil air compressor (also called “micro-oil lubricated air compressor”) is a compact, energy-efficient compressed air system that uses a minimal, precisely controlled amount of oil for lubrication, sealing and cooling-typically less than 1 ppm oil carryover in the output air. Unlike traditional oil-flooded compressors, it employs advanced rotor coating and optimized oil injection to achieve near-oil-free performance while retaining reliability and efficiency.

Key Features

• Ultra-low oil consumption (micro-dosing technology)
• High air purity (meets ISO 8573-1 Class 2 or better)
• Compact footprint and low noise design
• Reduced maintenance intervals vs. standard oil-flooded units
• Ideal for light industrial, laboratory, dental, and precision manufacturing applications

Why Use ‘Micro-Oil’ Instead of ‘Oil-Free ‘?

While oil-free compressors eliminate oil entirely, micro-oil models strike a practical balance: they deliver cleaner air than conventional oil-lubricated units-and often at lower cost and higher durability-without requiring expensive dryers or complex filtration systems typical of true oil-free solutions.

Rotor

Micro-oil injection point

Clean Air Outlet

Frozen compressed air dryer (refrigerated air dryer for short) is an industrial equipment that reduces the dew point of compressed air and removes moisture through refrigeration cycle. Its core components include evaporator, condenser, compressor and heat exchanger, among which the heat exchange chamber in contact with compressed air usually operates under pressure.

Is it a pressure vessel? The key depends on the design parameters.

According to China’s “special equipment safety law” and TSG 21-2016 “safety technology supervision regulations for fixed pressure vessels”, it is necessary to judge whether the equipment belongs to pressure vessels and meet the following three conditions at the same time:

• working pressure ≥ 0.1 MPa (Gauge pressure);
• volume ≥ 25 L;
• the medium is gas, liquefied gas or liquid with the highest working temperature higher than the standard boiling point..

The design pressure of most medium and large refrigerated air dryer evaporators/gas-water separation Chambers is 0. 7–1.0 MPa, the volume usually exceeds 30 L, and the processing medium is compressed air (gas), socomply with the definition of pressure vessel. But small integrated refrigerated air dryer (such as rated throughput < 1 m³/min, cavity volume < 25 L) may be exempted from supervision.

Actual regulatory requirements

refrigerated air dryer of pressure vessels must be designed and manufactured by qualified design units (A2 or D pressure vessel manufacturing license), special equipment product quality certificate is attached to the factory, and the use registration and regular inspection are handled according to regulations.

Evaporator (pressure chamber)

Compressed air inlet

Dry air outlet

Note: The above figure shows refrigerated air dryer pressure-bearing core component-evaporator cavity (blue frame), which directly bears the pressure of compressed air system as the pressure boundary, which is the key part to determine whether it belongs to the pressure vessel.

In the industrial pneumatic system, air compressor selection and equipment nameplate identification, the expression “0.6kg” is often seen, such as “working pressure: 0.6kg ‘. However, it needs to be clear:‘Kilometer’ itself is not a pressure unit., this is actually a shorthand for engineering habits, meaning0.6kg force per square centimeter (kgf/cm²), approximately equal0.059 MPa or 59 kPa.

Why use ‘kilograms ‘to describe the pressure?

Popular expression in the context of traditional engineering: 1 kgf/cm² ≈ 98.07 kPa, close to 0. 1 MPa to facilitate estimation. Therefore, ‘0.6kg ‘means 0.6 kgf/cm² ≈ 58.8 kPa, common in small pneumatic tools, packaging equipment and low pressure purging scenarios.

Unit conversion reference

• 0.6 kgf/cm² = 0.0588 MPa
• 0.6 kgf/cm² ≈ 58.8 kPa
• 0.6 kgf/cm² ≈ 8.5 psi (Pounds per square inch)
• 0.6 kgf/cm² ≈ 0.58 bar

note: Pascals are recommended in international standards (Pa) and its multiple (kPa, MPa), design documents and safety specifications should avoid using non-legal units such as ‘kilometer’ to prevent ambiguity or compliance risks.