Control unit for pressure-reducing valves to reduce vapor pressure in steam generating unit, closes pressure-reducing valve if steam pressure gradually falls below predetermined value in boiler, or else opens pressure-reducing valve

摘要

The control unit (8) closes the pressure-reducing valve (4) while steam pressure gradually falls below a predetermined value in a steam generator (2), and opens the pressure-reducing valve when the steam pressure exceeds the predetermined value. The aperture of the pressure-reducing valve is controlled depending on the function of the outlet pressure from the pressure transmitters (3,5). The pressure transmitter (3) is located between the pressure-reducing valve and the steam generator.