Thermostatic traps operate in response to the surrounding steam temperature. The operation and benefits of 3 different types are considered here - liquid expansion traps, bimetallic and balanced pressure thermostatic traps. Each operates in a different way and is suited to specific types of application.
Thermostatic Steam Traps
Liquid expansion steam trap
This is one of the simplest thermostatic traps and is shown in Figure 11.2.1. An oil filled element expands when heated to close the valve against the seat. The adjustment allows the temperature of the trap discharge to be altered between 60°C and 100°C, which makes it ideally suited as a device to get rid of large quantities of air and cold condensate at start-up.