STEAM TRAPS - TYPES, APPLICATIONS AND HOW IT IS WORKING

 STEAM TRAPS - TYPES, APPLICATIONS AND HOW IT IS WORKING

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What is a Steam Trap?

• Steam traps are a type of automatic valve that filters out condensate (i.e. condensed steam) and non-condensable gases such as air without letting steam escape. In industry, steam is used regularly for heating or as a driving force for mechanical power. Steam traps are used in such applications to ensure that steam is not wasted.

Different Types of Steam Traps:

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• Each model of steam trap has its own characteristics, and differences in traps' operating processes directly relate to whether or not they are suitable for a particular application. Steam traps can be divided into three different types based on their operating principles:

Mechanical Steam Traps:

• Mechanical steam traps (also referred to as “density traps”) include Free Float®, lever float, and inverted bucket steam traps. Mechanical traps operate by utilizing the difference in density between steam (or air) and condensate.

Thermodynamic Steam Traps:

• There are two varieties of thermodynamic steam trap: the thermodynamic disc and piston types. Thermodynamic steam traps operate by utilizing the difference in kinetic energy between high velocity steam (a gas) and slower moving condensate (a liquid).

Thermostatic Steam Traps:

• These include bi-metal, balanced pressure, and expansion thermostatic traps. Thermostatic traps operate by utilizing the difference in temperature between condensate that is close to steam temperature and sub-cooled condensate (or low temperature air).

How It Works: Steam Traps:

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Remove condensate and noncondensables without removing the steam

The American National Standards Institute defines a steam trap as a “self-contained valve that automatically drains the condensate from a steam-containing enclosure while remaining tight to live steam, or if necessary, allowing steam to flow at a controlled or adjusted rate. Most steam traps will also pass noncondensable gases while remaining tight to live steam.”

This type of valve has been in use since the early 1800s following the Industrial Revolution, when steam became more widely used as a heating medium instead of a motive source. There are three basic criteria for a valve to be considered a steam trap:

• automatically discharges condensate
• does not leak steam
• can also discharge noncondensable gases, such as air.

Steam traps are used in heating applications where latent heat is created and conveyed to a specific product (e.g., heating crude oil to decrease viscosity). Once the latent heat or energy has been transferred to the product from the steam, the steam condenses and forms condensate. If this condensate is not effectively removed from the process, the efficiency of the system will suffer.

A steam trap works to remove condensate and noncondensables without removing the steam. Manually throttling standard valves to allow only the condensate to escape is time consuming and inefficient. Manual valves must be constantly adjusted to take account of varying steam loads and the external environment; as a result, the risk of losing steam is much higher. Steam traps serve as a solution.

Applications:

Steam traps can be used anywhere there is a steam system and a need to discharge condensate.

Oilfield applications

• Bulk storage tanks
• Pressure reducing valve stations
• Steam mains
• Steam tracing
• Process heaters (heat exchangers and reboilers)

Industrial applications

• Industrial dryers (multibank pipe dryers and rotating cylinders)
• Laundries (garment presses and dry cleaning machines)
• Space heating
• Steam mains
• Steaming ovens
• Bulk storage tanks
• Process equipment (boiling pans, retorts, digesters, coppers, reboilers, evaporators, and vulcanizers)
• Space heating (heat exchangers, radiant panels, unit heaters, air heater batteries, and overhead pipe coils)
• Process vats
• Autoclaves

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