Pulstronic proportional valves from Asco/Joucomatic, Ft. Mill, S.C., are controlled by a dual-pulse coil. The compact dual coil requires the space of one standard solenoid coil, allowing for two separately operated 2/2 spool valves to be used in confined conditions.
The proportional valve operates in a closedloop structure. The pressure sensor, incorporated in the housing, constantly transmits instantaneous values to the controller for comparison with the setpoint. The Pulstronic is said to offer special advantages in applications where a fully adjusted pressure must be held on loss of voltage (fail-safe function) or for pressure control applications requiring constant flow.
The valves are available in sizes M5, G1⁄8, G1⁄4, or G1⁄2, and operate with setpoint values of 0 to 10 V, 0 to 20 mA, or 4 to 20 mA. Analog output of 0 to 10 V or a pressure switch output is available.