Samson 3277 - Preparation for Installation

6-4 EB 8310-6 EN
Start-up
6.1.3 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50 valve with 15mm rated
travel and 700cm² actuator with 30mm rat-
ed travel; 0.4 to 2bar bench range.
The signal pressure for half the actuator trav-
el (15mm) is 1.2bar. Adding it to the lower
signal pressure range value of 0.4bar re-
sults in a signal pressure of 1.6bar required
for spring compression. The new lower sig-
nal range value is 1.6bar and the new up-
per signal range value 2.4bar.
Î Write the new signal pressure range of
1.6 to 2.4bar on the actuator nameplate
as the operating range with preloaded
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 rst half of the actuator's bench
range can be used.
Example: DN50 valve with 15mm rated
travel and 700cm² actuator with 30mm rat-
ed travel; 0.2 to 1bar bench range.
At half the valve travel, the operating range
is between0.2 and 0.6bar.
6.2 Travel stop
Refer to Fig.6-2
In the version with travel stop, the maximum
and minimum actuator travel can be limited
as follows:
Direction of ac-
tion
Min. stop Max. stop
Stem extends (FA) 0 to 125% 50 to 125%
Stem retracts (FE) 0 to 100% 50 to 100%
6.2.1 Bottom travel stop
(minimum travel)
1. Loosen top lock nut (A74) and unscrew
cover (A73).
2. Loosen bottom lock nut (A74) and turn
the adjustment nut (A70) to adjust the
travel stop.
3. Tighten bottom lock nut (A74).
4. Attach the cover (A73) and retighten the
lock nut (A74).
6.2.2 Top travel stop (maximum
travel)
1. Loosen top lock nut (A74).
2. Adjust the cover (A73) to the required
travel stop.
3. Retighten top lock nut (A74).
Left half: Actuator stem retracts (FE)
Right half: Actuator stem extends (FA)
A73
A74
A70
A75
A5
A7
A50
A5 Diaphragm plate
A7 Actuator stem
A50 Top actuator stem
A70 Adjustment nut
A73 Cover
A74 Lock nut
A75 Top diaphragm case
Fig.6-2: Travel stop