Table of Contents
Advertisement
3 Design and principle of operation
The Type 3379 Pneumatic Actuators with
spring-return mechanism are used in con-
junction with a valve as a control unit suit-
able for the food and pharmaceutical indus-
tries.
The signal pressure p
piston surface (5) which is counteracted by
the spring(s) (4). The bench range is deter-
mined by the number of springs used and
their compression, taking into account the
rated travel.
Actuator stem
retracts (fail-open)
3
1
Pressure connection to control the
actuator
2
Piston seal
3
Vent plug
4
Spring(s)
5
Piston
Fig. 3-1: Sectional drawings of Type 3379
EB 8315 EN
creates a force on the
st
Actuator stem
extends (fail-close)
10
9
8
3
1
5
2
4
7
6
Design and principle of operation
The actuators are designed for a maximum
travel of 15 mm. A spring compression is
only possible with smaller travels.
The travel H is proportional to the signal
pressure p
. The direction of action of the ac-
st
tuator stem depends on how the springs are
installed in the actuator.
The supply air is connected for both operat-
ing directions to the top connecting plate.
Actuator stem
extends (fail-close)
3
1
6
Base
7
Actuator stem
8
Cover
9
Position indicator (valve OPEN/
CLOSED)
10
Dome (visual indicator)
10
9
8
1
5
2
4
7
6
3-1
Advertisement
Table of Contents
