Steam traps are indirectly actuated valves and are classified into four groups: mechanical, thermal, thermostatic and specialty traps.
Mechanical traps are typically the simplest and oldest type of trap. Mechanical traps are designed with a device that floats on the steam and will vent it when the steam temperature rises above the trap’s operating temperature. Generally, this type of trap has a short response time, low cost and can be easily installed in most systems.
Thermal traps are designed to respond to changes in the steam flow rate. They usually have a thermostatic element in the body of the trap, which is connected to a valve that is actuated by the change in the flow rate. When the steam flow rate drops, the valve opens to vent the steam.
Thermostatic traps operate by sensing the temperature of the steam as it enters the trap. The temperature of the steam is what actuates the valve. When the steam reaches the set temperature, the valve opens to vent the steam. This type of trap is generally better suited for large systems or where high pressure steam is used.
Specialty traps are typically the most expensive type of trap available. Specialty traps use a combination of thermostatic and thermal elements to vent steam. The specialty traps are designed for specific applications such as temperature/pressure sensitive operations or applications that require special materials of construction.
No matter which type of steam trap is chosen, there are some common criteria that must be considered. These include the capacity of the trap, the type of media it will be used with, the pressure, the temperature and the performance of the trap in order to ensure the system is properly maintained. Capacity is important to consider because too small a trap will not vent the steam properly and too large of a trap can cause instability in the system. Also, the type of media is important to consider because some traps are designed for use with specific media such as water, oil or air. Different traps also vary in their pressure and temperature capabilities, which need to be considered for the system. Finally, the performance of the trap should be determined in order to ensure it is operating as intended.
Overall, steam traps are used to ensure the proper performance of a steam system. By considering the criteria mentioned above, one can choose the best trap for their system and ensure it is operating efficiently.
