Gas Powered Stop Valves Type RALK Series

Technical parameters：

Nominal pressure: 2.8MPa         Applicable temperature:-50℃～+150℃

Test pressure: 4.2MPa                 Applicable medium:ammonia,fluorine,etc.

Characteristics:

- RALK are servo-operated valves normally closed and pneumatic opening by means of refrigerant gas from external high pressure     line, acting upon power piston.

- On the bonnet are fitted one external joint, nut & nipple connection to gas inlet, and two solenoid pilots AEVM type:

   - a-RALK-NC/NO, with one AEVM-NC, (normally closed pilot) on A, and one AEVM-NO,(normally open pilot) on B.

   - b-RALK-NC/NC, with one AEVM-NC, (normally closed pilot) on A, and one AEVM-NC on B.

- The solenoid valve A shut-off or opening the flow of gas to the top piston

   chamber, to close or open the main valve. But the solenoid valve B has to 

   be opened to relieve this gas of the chamber to allow closed again the 

   main valve when the solenoid valve A is closed.

-  RALK valves are designed to use with ammonia and other common 

   fluorinated refrigerants, for use in suction lines or any application that 

   need a valve normally closed with automatic opening for short periods,

   and with a minimum differential pressure between inlet-outlet or even 

   with △p=0.

-  While the valves are opened, there is not a bleed of gas around the piston,

    and only when the solenoid A shut off the flow of gas upon power piston,

    and the solenoid B is open to allow close again the main valve, the gas 

    of this chamber is relieved upstream.