New delhi-based central agencies manufactures pneumatically actuated valves that have resulted to be an effective replacement for manually actuated process control valves. These valves are on-off type and can be linked up with the main control system of the process plant. These consist of a pneumatic rotary actuator [double acting or single acting] that works through 90 deg angular movements of ball, plug or butterfly valves. These are available for variety of fluids such as steam, oil, air, water, and various chemicals in different sizes depending upon the pipeline size. Pneumatic actuators are mounted directly on the shaft of valve. These actuators can also be supplied with solenoid valve mounted on them as an integral unit. Flameproof solenoids can also be supplied according to the uses. Devices such as dampers, louvers, positioning equipment, sorting systems on conveyers, operating turntables, indexing mechanisms, furnace doors, ducting flaps, and big switches can be operated with the actuators. The design uses two opposite moving pistons, which give powerful torque with the help of rack mechanism and move the pinion through an angle of 90 deg when the air connection is pressurised. The cover of actuator has two ports, when air is admitted through on export other post is exhausting and vice-versa. The actuator spindle is extended as a standard characteristic to facilitate manual operation on air failure. The actuator can be altered into single acting spring return designs by forming spring at the both ends of the actuator. Material of construction and technical specifications are as follows: * body: hardened and anodised aluminium * sleeve: seamless tube honed to fine finish * spindle: steel * o-rings: synthetic rubber * valves: ss 304, ss 316, cast steel * rotation: 90 deg angular clockwise * operation time: 0.5-4.8 seconds * air consumption: 0.2-17.1 ltrs/stroke * temperature: 10-80 deg c * torque output: 0.5-108 kg * pressure range: d a 2.8-8.5 kg/sq cm; s a 5.5-8.5 kg/sq cm * medium: air, oil and inert gases.
