Is a screw compressor considered a pressure vessel?

Definition of Basic Concepts for Screw Compressors and Pressure Vessels

In industrial production,Screw compressor(Usually referring to screw-type air compressors) its primary function is to compress gas and increase its pressure through mechanical motion; essentially, it belongs to a type of…Power machinery and equipment. AndPressure vesselIt refers to a sealed device that contains gases or liquids and is designed to withstand a certain pressure. From the perspective of its core function, the compressor unit of a screw compressor does not qualify as a pressure vessel.

Which components in a screw compressor system are classified as pressure vessels?

Although the screw compressor’s main unit is not a pressure vessel, its operating system includes several sealed components used for storage and separation. If these auxiliary components meet specific parameter criteria, they are classified as pressure vessels. Common examples include:

• Gas storage tank: Used to store compressed gas and to balance pressure fluctuations in the system, it is a typical pressure vessel.
• Oil-gas separator vessel: Inside a screw compressor, it is used to separate lubricating oil from compressed air; it also operates under high working pressure and is typically classified as a pressure vessel.

Statutory Criteria for Pressure Vessels

To determine whether the auxiliary components of a screw compressor qualify as pressure vessels subject to statutory regulation, strict adherence to the safety technical specifications for special equipment is required. Typically, all three of the following core conditions must be met simultaneously:

• Work stress: Maximum working pressure greater than or equal to 0.1MPa (Gauge pressure).
• Volume and Dimensions: Volume greater than or equal to 0.03m³ (i.e., 30 liters), and the inner diameter is greater than or equal to 150mm.
• Filled medium: The contained medium is a gas, a liquefied gas, or a liquid whose maximum working temperature is equal to or higher than its standard boiling point.

Only when the parameters of components such as gas storage tanks or oil–gas separators simultaneously meet the aforementioned conditions shall they be included in the special equipment management catalog for pressure vessels.

Equipment Security Management and Compliance Recommendations

For screw compressor auxiliary components classified as pressure vessels, enterprises must strictly comply with the relevant safety regulations during their use and management.

• Registration for UseBefore putting the equipment into service or within the prescribed time after commissioning, it shall be registered with the local special equipment safety supervision and administration authority and a certificate of registration shall be obtained.
• Periodic inspectionIt is mandatory to engage a qualified special equipment inspection agency to conduct periodic inspections in accordance with the prescribed inspection cycle, thereby ensuring that the equipment remains in a safe operating condition.
• Personnel QualificationsPersonnel responsible for the safety management of pressure vessels shall undergo specialized training and obtain the corresponding qualification certificate for operating special equipment.