ELECTRO-PNEUMATIC CONVERTER

摘要

PURPOSE: To provide an electropneumatic converter that is readily convertible from a valve positioner into a pressure transducer and vice versa. CONSTITUTION: An electropneumatic converter device 10 includes modular components, and a supporting housing structure enabling it to be readily convertible from a current-to-pressure positioner into a current-to-pressure transducer. A valve positioner includes a housing 12, a modular base 26 and a separable field terminal box. A self-contained cover is mounted to an enclosure with no additional mounting parts. A plastic pneumatic relay 48 is ultrasonically welded so that no metal mounting parts are used and the assembly time is shortened. Open channels are cut in the housing surface cooperating with a gasket to provide fluid passageways between the housing 12 and the modular base 26. Pressure gauges 50 are removably mounted on a modular unit. A supply biased pneumatic pressure relay has supply pressure channeled to a support port and to a support bias cavity through a capillary hole.