Gas fittings and equipment are designed for use in natural gas transmission and supply pipelines, as well as in distribution systems. These devices allow for turning the supply on or off, and the system also allows for setting the amount, direction and pressure of gas flow.
The following parameters are critical for any gas fittings:
Nominal pressure (PN) is the maximum pressure at 20 °C when continuous operation of various connection points between the fitting (equipment) and the pipeline is provided. Nominal diameter (DN) is the value used for designating parts that are to be connected in systems and pipeline networks.
Fittings for gas systems are classified depending on their intended use as follows:
Shut-off valves are used for multiple isolating operations of systems and devices, as well as for isolating gas pipelines from certain sections. Shut-off valves, cocks and slide valves are used for this application.
Control valves are used to change and maintain pressure within the set range. They include butterfly valves, slide valves and so on.
Safety valves are used to prevent gas pressure from rising above the set value. Safety relief valve can be named as an example.
On/off valves and emergency valves are used for fast automatic isolation of various gas systems and devices, as well as gas lines where set operating parameters are violated; for example, safety shutoff valve.
Check valves: used to prevent gas flow in the opposite direction.
Condensate drains are used to automatically remove condensate that is collected in the condensate tank and in lower points of pipeline systems.
When selecting gas fittings, one must consider the chemical and physical properties of materials used for manufacturing gas fittings.