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Control Hardware: Self-acting Actuation
Basic self-acting control theory is discussed, alongside the different types of direct-acting and pilot-operated valves, controllers, and applications for the proper selection of temperature and pressure control of steam and water systems.
This tutorial gives a basic introduction to what self-acting temperature control systems are and how they operate. The various different types of valves and controllers are briefly discussed along with typical applications for steam and water systems.
Four different types of temperature controllers are considered, including fail-safe high limit protection. Popular applications for self-acting controls are listed for process, heating and cooling systems.
Various types of self-acting pressure controls are examined in this tutorial, including direct acting bellows operated and diaphragm operated valves, and pilot operated valves, with guidelines on how to select and install them correctly. Pressure reducing valves are considered together with pressure maintaining valves and surplussing valves, alongside some typical applications.