Why self-acting controls are needed, the various options available, and their practical application in controlling temperature and pressure in steam and water systems.
The differences between vapour tension systems and liquid-filled systems are explained, with animated illustrations showing how different options work. We also look at where and why self-actuating temperature controls are used.
These systems are a vital safety feature. They operate by either adjustment at a sensor, an actuator, or by remote operation. We also examine high limit cut-out devices and the many environments where they are used.
Usually used to reduce the amount of steam pressure in a system, self-acting pressure controls tend to be either direct acting or pilot operated. This section illustrates both, looking at choices that determine where each would be used. We also look at pressure maintaining valves, and why these are sometimes needed.