Pneumatic, Electrical Motor and Electro-Thermal Drives for Final Control Elements, Valve Drives

TEMPERATURE, PRESSURE, HUMIDITY, DENSITY AND LEVEL CONTROLLERS FOR USE IN HEATING, VENTILATING AND AIR CONDITIONING SYSTEMS; COMPONENTS FOR SAID CONTROLLERS-NAMELY, PNEUMATIC, ELECTRIC AND ELECTROTHERMAL DRIVES OR VALVES FOR REGULATING SAID QUANTITIES, AND VALVE DRIVES FOR DRIVING SAID REGULATING VALVES