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Pneumatic and electro- pneumatic valve positioner

Pneumatic and electro- pneumatic valve positioner
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Pneumatic and electro- pneumatic valve positioner - 1

Datasheet Valve positioner Type SP405 Type SPE405 • High accuracy • High capacity • Clear visual position indication • Good resistance to vibration • Easy setting Pneumatic Electro-pneumatic The SOMAS pneumatic positioner type SP405 (20 – 100 kPa) and the electro-pneumatic type SPE405 (4 – 20 mA) are developed to meet the demands from the process industry. The SOMAS positioners are intended for a rotary motion up to 90°. They are developed for quarter turn actuators and valves but can easily be adapted for actuators with a linear motion. A number of different cam discs are available to cover various signal ranges, angles of rotation and valve characteristics. All cams discs are for a rotary motion of 60°-90°. Other types of cam discs on request.

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Pneumatic and electro- pneumatic valve positioner - 2

Function SP405 (Pneumatic type) A pneumatic input signal (20-100 kPa bar*) acts on a diaphragm (41) and via the balance arm (46) the pilot valve (40) is controlled. When the input signal increases, the pilot valve distributes supply air to one side of the piston while the other side is vented. The cam disc (32), which is adjustable to the shaft (26), transmits the rotary motion of the actuator to the feed-back arm (35). The feed-back arm acts on the feed-back spring (53) and when there is a balance between the force from the diaphragm and the force from the feed-back spring, a new balanced...

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Pneumatic and electro- pneumatic valve positioner - 3

Installation Rotary motion The transmission of the rotary motion between actuator and positioner is of a new design. No extra parts are needed for mounting the positioner SP/SPE405 on the actuator type A. The setting of range is done with the adjustment screw (7). The zero-point can easily be adjusted from the outside by means of a screwdriver on screw (50). Mounting on a standard actuator To reach the zero-point screw the cover (31) has to be opened (see the manual Mi-805). A mounting block is used as a standard solution to mount the positioner to the actuator. When the mounting block is...

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