Well designed steam systems produce clean dry steam for delivery at high pressure - the best quality steam at the lowest cost.
Lower pressure steam is usually needed at the point of use.
Effective control demands an automatic valve that can reduce steam pressure accurately, reliably and at a cost to suit the application.
Self-acting valves (can operate without the need of external power).
Pneumatic signal and actuator operated valves.
Controls and Instrumentation - An Introduction
Your closest Spirax Sarco is