pressure reducing valve shows

   A pressure regulator (also called pressure reducing valve) is a valve that automatically cuts off the flow of a liquid or gas at a certain pressure.

  Regulators are used to allow high-pressure fluid supply lines or tanks to be reduced to safe and/or usable pressures for various applications.

  Gas pressure regulators are used to regulate the gas pressure and are not appropriate for measuring flow rates. Flowmeters, Rotometers or Mass Flow Controllers should be used to accurately regulate gas flow rates.

Steam Pressure Reducing Valve Features:

Design & Manufacture: GB
Face to Face Dimension: GB
Inspect & Test: GB/T13927-92, GB/J9092
Operation: Manuel 
Pressure Rating: PN16, PN25, PN40, PN64

Standard Material Construction:

Body/Bonnet:  Cast Iron, Carbon Steel and Stainless Steel
Disc:  Cast Iron, Carbon Steel and Stainless Steel
Secondary Disc/Seat:  Stainless Steel
Diaphragm:  Stainless Steel
Main Disc/Seat:  Stainless Steel
Piston:  Stainless Steel
Secondary Spring:  Chrome Vanadium Steel 
Main Spring:  Chrome Vanadium Steel
Adjusted Spring:  Silicon Manganese Steel
Piston Ring:  Alloy Cast Iron

Direct Acting Bellows Pressure Reducing Valve

Changes in downstream pressure are sensed by the bellows, which expands or contracts dependin on the pressure change.

The movement of the bellows will be directly transferred to the spring. which will open or close the main valve, thus keeping the

down stream pressure at a certain level. Changes in down stream pressure are sensed by the pilot valve mechanism( bellows

connected with a pilot valve unit) through a signal line, which connects the pilot valve regulator with the secondary pressure side.

Movement of the bellows will open or close the pilot valve, regulating the amount of steam influencing the movement of the piston,

which will close or open the main valve, thus keeping downstream pressure on a stable level.

                                                                                      GOOLE pressure reducing valve:http://www.chinavalve1.com/product/product_34_48_1.html