Choosing the correct welding gas regulator interface is crucial, as the key lies in the type of gas cylinder and gas type. Using the wrong interface can lead to installation failure, gas leakage, and even safety accidents.
Core principle: Gas characteristics determine interface type
Different gases have different chemical properties (such as flammability and flammability) and physical properties (such as pressure), so it is necessary to design different interfaces to prevent misconnection and avoid connecting combustible gases to combustion gas cylinders, which can cause danger.
The two most common interface standards；
There are mainly two mainstream interface standards in the welding field:
1. CGA interface: mainly used in North America, the United States, Canada and other regions. CGA is the abbreviation for Compressed Gas Association, whose standards are represented by numbers, such as CGA-580.
2. BS/DIN interface: mainly used in Europe, China, and most other regions of the world. BS is a British standard, DIN is a German industrial standard. The “threaded interface” we often refer to usually refers to this type.
How to select regulator interface based on gas (BS/DIN standard)
You need to observe two key characteristics: thread specification and sealing method.
1. Thread specifications
Positive thread (right-hand thread): Most non combustible gases use positive threads. Rotate clockwise to tighten. This is the most common type.
Reverse thread (left-hand thread): All combustible gases (such as acetylene, propane, hydrogen) must use reverse threads. Rotate counterclockwise to tighten. This is an important safety sign that reminds operators that this is a flammable gas.
2. Sealing method
Flat sealing: By aligning the flat surface at the end of the regulator interface with the flat surface at the valve mouth of the gas cylinder, a gasket (usually made of nylon or brass) is placed in the middle to seal. This is currently the most mainstream sealing method.
Cone sealing: The cone at the end of the regulator interface is directly compressed and sealed with the cone at the valve door of the gas cylinder (without a gasket). This method is older but still in use, commonly found in some carbon dioxide bottles.
Summary of selection steps
Confirming the type of gas inside the cylinder: This is the most basic step. Is it argon, carbon dioxide, oxygen, or acetylene?
Observe the valve door of the gas cylinder:
Check the thread: Is the external thread of the valve interface a straight thread or a reverse thread? This is the key to distinguishing between combustible and non combustible gases.
Check the sealing surface: Is the valve door flat (requires a gasket) or tapered (without a gasket)?
Purchase the corresponding regulator:
Tell the supplier what gas you want to weld (such as “argon regulator for argon arc welding” or “carbon dioxide regulator for gas shielded welding”), and they will give you the correct model.
The safest method: Bring your old regulator or take a clear photo of the gas cylinder valve door to show to the supplier to ensure that everything is foolproof.
Important safety reminder
Do not mix: Never attempt to connect an oxygen regulator to a combustible gas cylinder, and vice versa.
It is strictly prohibited to use grease: especially for oxygen regulators, any oil stains will undergo severe oxidation reactions (explosions) in high-purity oxygen environments.
Leak detection before use: After installing the regulator, check for any bubbles at the interface with soapy water to ensure there are no leaks.
Use specialized gaskets: The gaskets for flat sealing interfaces are disposable or consumable parts. It is best to check them every time the gas cylinder is replaced, and replace them immediately if damaged. Do not use metal washers instead of nylon washers.