24
EB 8310-8 EN
Mounting and start-up
5.2.3 Adapting the travel
range
In some cases, the valve and actuator have
different rated travels. Depending on the di
-
rection of action, proceed as follows:
Direction of action: actuator stem extends
Always use actuators with preloaded springs
when the valve's rated travel is smaller than
the rated travel of the actuator.
Example:
DN 200 valve with 120 mm rated
travel and 1400 cm² actuator with 250 mm
rated travel; 0.8 to 2.55 bar bench range.
The lower signal bench range for a preload
-
ing of 50 % (125 mm) is ~1.65 bar.
Î
Write the new signal pressure range of
1.65 to 2.55 bar on the actuator name
-
plate as the operating range with pre
-
loaded springs.
Direction of action: actuator stem retracts
The springs of actuators with "stem retracts"
action cannot be preloaded. When a SAM
-
SON valve is combined with an oversized
actuator (e.g. the rated travel of the actuator
is larger than the rated travel of the valve),
only the first half of the actuator's bench
range can be used.
Example:
DN 200 valve with 120 mm rated
travel and 1400 cm² actuator with 250 mm
rated travel; 1.2 to 3.8 bar bench range.
At half the valve travel, the operating range
is between 1.2 and 2.5 bar.
5.3
Additional fittings
Vent plug
Vent plugs are screwed into the exhaust air
ports of pneumatic devices. They ensure that
any exhaust air that forms can be vented to
the atmosphere (to avoid excess pressure in
the device). Furthermore, the vent plugs al
-
low air intake to prevent a vacuum from
forming in the device.
Î
Locate the vent plug on the opposite side
to the workplace of operating personnel.
Î
On mounting valve accessories, make
sure that they can be operated from the
workplace of the operating personnel.
The workplace of operating personnel is the
location from which the valve, actuator, and
any mounted valve accessories can be ac‑
cessed to operate them.
Note