Mankenberg M XTRA RP 840 Betriebsanleitung Seite 17

Pressure Control Valves
Pilot-operated Control Valves RP 840
additional technical information
ATTENTION
In principle, the general Operating Instructions for the installation and commissioning of pilot-operated pressure control valves take strict
precedence.
The described components have been selected as examples. The configuration of the valves as well as the routing of the sense lines and position of the throttle
valves are relevant.
Layout
The pressure reducing valve RP840 consists of a main valve and a pilot valve. Here the main valve has been designed as differential pressure control valve and the
pilot valve as a pressure reducing valve. The valves are interlinked with sense lines in which two throttle valves and a dirt trap have been integrated. The inert gas
is supplied to the vessel / tanks via the main valve, whilst the pressure within the vessel / tank is set and controlled through the pilot valve.
Operating principle
In pressureless state, the main valve is closed by a pre-tensioned spring. The pilot valve is in open position.
During start-up the fluid gets to the upstream side (pv) of the main valve, then into the valve's control chamber and via the throttles D1 and D2 into the regulating
chamber of the main valve. With the downstream pressure (ph) being lower than the adjusted setpoint of the pilot valve, the pilot valve cone is kept in open
position by the valve spring. No pressure can build up in the control chamber of the pilot valve because the fluid can flow off towards the vessel / tank.
The main valve is designed as differential pressure control valve. The valve opens and closes depending on the adjusted differential pressure between the up-
stream pressure (pv) and the intermediate pressure adjusted via the throttle D2. As long as the pressure to be regulated in the vessel / tank, which is adjusted via
the pilot valve, has not been reached, the main valve remains open and lets the inert gas flow to the vessel / tank.
Once the pressure within the vessel / tank, which has been adjusted via the pilot valve, is reached, the pilot valve closes. Thus, the intermediate pressure in the
lower control chamber of the main valve rises and the main valve closes. The inert gas supply to the vessel / tank is interrupted.
Once the pressure within the vessel / tank falls below the pressure adjusted via the pilot valve, this valve opens. Thus the intermediate pressure towards the main
valve falls, after which the main valve opens again and the vessel / tank is again supplied with inert gas.
The throttles D1 and D2 serve for synchronising the system. Throttle D1 influences the time response of the entire control unit consisting of main valve and pilot
valve. Throttle D2 adjusts the opening velocity of the main valve.
Assembly
The pilot-operated pressure reducing valves are delivered either disassembled into components or as an assembled unit.
For the disassembled into components option: The instructions for the assembly can be found in the assembly video (YouTube)
Either click on the link or use the barcode: ASSEMBLY // PRESSURE REDUCING VALVE RP 840
Assembled unit option: The valve is supplied in a piped configuration with throttle valves D1 and D2 and a strainer in the sense line.