Charging
Dome loaded regulators are supplied with the dome un-pressurised. To get the regulator working or to change the set pressure, the dome must be charged with an inert gas such as air or nitrogen. DO NOT use liquid.
If the process gas can be vented safely to atmosphere it may be used to charge the dome – we call this “Body Loading”. Alternatively, the dome may be charged from an external source – we call this “Mono Loading”. Provision can be made for either or both methods (“Dual Loading”).
See Figure 3 in the Guidance document
Body Loading Charging Procedure
Unscrew the Vent needle valve approximately two turns. Process air or gas will vent past the valve. This needle valve acts as a crude regulator to give a reduced pressure to charge the dome.
Unscrew the Body Loading needle valve a small amount. This needle valve allows you to control the charging rate. The outlet pressure rises as the dome is charged.
When the outlet pressure reaches the required value, close the Body Loading and Vent needle valves.
External Loading Charging Procedure
If there is a plug in the External Loading Port, remove it.
Connect a source of pressure to the External Loading Port. Ideally, this should be from an adjustable regulator. Alternatively, the external pressure can be controlled by a needle valve.
Set the external pressure to zero. Undo, but do not remove the External Loading needle valve.
Apply external pressure to the dome. The outlet
pressure will rise as the dome is charged.
When the outlet pressure reaches the required value, close the External Loading needle valve.
