END ARMATUREN DA2D3, Original Operating Manual, Page: 15 / 40

DG2D - 07/2016 http://www.end.de 15
Description of function
4.5.3 Normally close against the flow direction
The in neutral position closed valve obtains this function by a spring, which acts in close direction.
By feeding with compressed air the pilot pressure moves the piston against the spring and lift up
the valve disk from the seat. Therefore the valves open.
The valve closes against the flow direction only by the spring force. Therefore the valve closes
slowly and prevents pressure shocks in the pipes.
Fig. 4.6 - Description of function - Normally close against the flow direction
4.5.4 Normally open, close against the flow direction
The in neutral position opened valve obtains this function by springs mounted under the piston.
The valve closes against the flow direction only by the pilot pressure.
4.5.5 Double acting
The valve closes against the flow direction only by the pilot pressure. The valve opens with the flow
direction only by the pilot pressure.
Fig. 4.7 - Description of function - Normally open, close against flow direction; Double acting
© END-Armaturen GmbH & Co. KG
© END-Armaturen GmbH & Co. KG