The pneumatically controlled two stage piston actuator
is made of two plastic actuators. The two stages can be
independently actuated from each other.
In order to open the valve completely with the full flowrate,
the lower piston has to be actuated. Limited opening or
flowrate is possible by actuating the upper piston.
An adjustable stroke limiter allows to adjust the linear
movement of the upper position. An optical indicator
which is directly connected with the valve spindle shows
the stroke.
The control function of the valve is normally closed (Cf.1).
Application
The valve is mainly used for filling with controlled filling of
a tank, container or barrel. For filling, the valve is completely opened with the full flow rate. At the end of the filling cycle, the valve automatically reduces to the second
stage of filling with a reduced flow rate for an accurate
finish fill.
