16
http://www.end.de
DG - 10/2019
Description of Function
4.5.1.3
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.
Fig. 4.6 - description of function - normally open, close against flow direction; double acting
Fig. 4.5 - description of function - Normally close against the flow direction
4.5.1.2
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.
4.5.1.4
Double acting
The valve closes against the flow direction only by the pilot pressure. Also the valves opens with
the flow direction only by the pilot pressure.
©
EN
D-
Au
tom
ati
on
G
mb
H
&
Co
. K
G
©
EN
D-
Au
tom
ati
on
G
mb
H
&
Co
. K
G
