霍夫曼专业系列2000减压阀
Hoffman Specialty Series 2000 Pressure Reducing Valve

Series 2000 Pilot-Operated Regulators consist of a main valve that is controlled by a single or combination of pilot control valves. The Hoffman Specialty Series 2000 Pilot-Operated Regulator line includes over 55 main valves with 24 pilots and hundreds of possible combinations to cover a wide range of temperature, pressure and capacity options.

There are a number of types of pilot control valves available from Hoffman Specialty:

• Series SPS Spring Pressure Control Pilots – for self-contained pressure regulation
• Series STPA Self-Contained Temperature Control Pilots – for control of heated fluids
• Series AP Air Pressure Control Pilots – for remote pressure control using air pressure
• Series 315 PNT and Series 240 PNT Pneumatic Temperature Control Pilots – for rapidly changing load requirement applications
• Combination of Control Pilots

Different types of pilot valves can be used in combination to control more than one function or as a safety override. For example, a temperature pilot may be used in conjunction with a spring pressure pilot to control both temperature and pressure. Or, a temperature pilot may be used with a solenoid pilot to provide automatic shutdown when an over-temperature condition occurs.

Operation of Series 2000 Pilot-Operated Regulator Main Valve:

The regulator main valve is held closed by the pressure on the diaphragm from an internal main spring. Pilot control valves control steam flow from the upstream supply side of the main valve to the underside of the diaphragm of the main valve. When the pilot valve opens, steam flows through the pilot and pressure builds in the signal line, applying pressure under the main valve diaphragm. This pressure force compresses the main valve spring and the main valve opens.

Under constant steam demand, the pilot and main valve remain relatively motionless. As the system approaches the pilot set point, the pilot valve begins to close. Less steam passes through the pilot and through the signal line. Pressure in the signal line decreases as steam passes through a small bleed orifice on the main valve. With lower steam pressure under the main valve diaphragm, the main valve spring forces the main valve to close.