The SA-1 is an analogue positioner available in a pneumatic and electro-pneumatic version. The positioner has a heavy duty design making it suitable for use in very harsh conditions. It is used as the control part of the pneumatic valve set in oil and gas, refining, chemical, power, metal production and other fields with automated systems. The pneumatic version accepts a 3-15 psi (0.2-1 bar) signal and the electro-pneumatic version a 4-20 mA signal.
When using the electro-pneumatic version an I/P converter is installed on the pneumatic positioner which allows an electric signal to pilot the positioner. It is based on the balanced-forces principle; air distribution to actuator chambers is done by a spool.
It can be fitted on single or double acting actuators and the operational stroke is between 3-100mm for reverse action with the spring extended.
The standard operational stroke length is 2-65mm for both direct and reverse action with a compressed cylinder spring with a maximum diameter of 200mm. The positioner works on a force balance type operating principle with linear characteristics. The feed-back element consists of a spring with a linear characteristic, actuated by the piston movement: no external elements for movement intake are required. The SA-1 positioner is very compact and can be fully installed on the servo-control system (It is especially suited for pump use).
This positioner is a double acting positioner but it can be used as a single acting one.
Heavy duty design.
Intuitive mechanical and pneumatic construction.
Split range signal.
Available as full stainless steel spool valve.
No external feedback system
Suitable for standard, offshore, sandstorm, copper free ambient conditions.
Single and double acting actuators. Low and high ambient temperature.