RMA Products Profile
Accurate, Reliable, and Industry-Leading Metering Solutions
RMA Control
Electro Hydraulic Control
Together with our niwatec NWS Scotch yoke actuator or the NWLA linear actuator, our electro-hydraulic control guarantees a trouble-free and safe procedure during all kinds of operating conditions.
Oil is pumped out of the oil tank into the bladder or piston accumulator by means of an electric oil pump. Once the pressure needed for the unit is reached, the pump turns off automatically. Upon receiving a signal from the control, one of the two solenoid valves (either for opening or for closing the ball valve) opens the corresponding pipe and hydraulic oil pours from the accumulator into the hydraulic cylinder. The actuator drives and opens or closes the ball valve. In case of a power breakdown, one or more emergency strokes can be undertaken according to customer‘s specification.
Various Possibilities To Operate The Unit
The modular structure facilitates maintenance and the integration of security relevant components such as linebreak control systems, high-, low- or differential pressure pilots and ESD-valves.
01
By remote signal from the process control system
02
Service directly on site (manual operation) using the control or the emergency manual override at the solenoid valve
03
Stroke with pressure from the bladder accumulator in case of power breakdown (emergency operation 1)
04
By operating the hand pump (emergency operation 2)
Standard Features
- Operational pressure up to 250 bar
- For double or single acting actuators
- Electric explosion protection according to Ex-e, Ex-d or Ex-ia
- CE and ATEX 94/9/EG certified
- control voltage: 24 V DC, 48 V DC, 110 V DC , 220 V DC or 115 V AC or 230 V AC
- Temperature range: -29 °C to +50 °C
- Control components mounted in stainless steel casing or – on request – on stainless steel panel
- Tubing and fittings made of stainless steel, manufacturer of fittings according to customer‘s specification
- Position feedback „open“ or „closed“
- Manual emergency operation by means of hand wheel or hydraulic hand pump
- Pressure switch for signalisation of minimum pressure needed
- local / remote switch (maintenance switch)
- bladder accumulator for emergency strokes (number of strokes according to customer specification) corresponding to PED, GOST, or ASME VIII div.1
Optional Features
- Extended temperature range: -60 °C to +60 °C
- Low or high pilots for pipeline protection
- Coils with low power consumption (approx. 3 W per valve)
- Linebreak system (electric or mechanic)
- Differential pressure switch (electronic or mechanic)
- ESD, Partial Stroke or SSV function
- Regulating control systems
- Profibus, modbus or foundation fieldbus interface boar
- Redundant solenoid valves
- SIL 2 / SIL 3
- Low regulating times (down to < 1 second) for single acting actuators
- Control cabinet heating incl. thermostat
- Cathodic separation
- Fire protection
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