Gas cylinder connectors are standardized fittings designed to safely connect gas cylinders to regulators and equipment, with specific types designated by national and international standards (like CGA, DIN, and BS) to prevent dangerous cross-contamination and ensure compatibility. The correct connector depends on the specific gas, purity level, and target region.

Common Gas Cylinder Connector Types and Standards

Different regions and applications use distinct standards to ensure that only the correct gas can be used with a compatible system.

CGA (Compressed Gas Association):

The standard in the USA and North America, with various numbers (e.g., CGA 580 for inert gases like argon and nitrogen, CGA 540 for oxygen, CGA 320 for carbon dioxide) assigned to specific gases.

DIN (Deutsches Institut für Normung):

Widely used in Germany and parts of Europe, these use metric threads and are defined by the DIN 477 standard.

S (British Standard):

Used in the UK, these are specified under the BS 341 standard and include “bull nose” and “flat face” styles.

ISO 5145:

A global standard governing various thread types for high-pressure gas cylinders, aiming for international compatibility.

Clip-On Connectors:

Commonly used for domestic LPG (liquefied petroleum gas) such as butane and propane, these offer an easy-to-use, quick-connect solution, with specific sizes (e.g., 21mm, 27mm) for different bottle types.

 

Key Selection Factors for Gas Cylinder Connector Types

Choosing the correct connector is crucial for safety and functionality.

Gas Type:

Each gas (or gas mixture) has a designated connector type to prevent accidental use with incompatible equipment.

Material:

Connectors are typically made of brass for most non-corrosive industrial gases, and stainless steel for highly corrosive or high-purity specialty gases to prevent contamination.

Pressure Rating:

The connector and the associated regulator must be rated for the maximum pressure of the gas in the cylinder.

Seal Type:

Connections can use either a tapered thread with a sealant (like PTFE tape) or a parallel thread with an O-ring seal under the shoulder of the valve body