25 September 2023


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1.) Def: It is a valve Device that discharges condensate and air from the steam lines without discharging the steam.

In order to obtain the fast heating of the product and equipment.


2.) Functions:

Discharge condensate as soon it is formed.

Does not allow steam to escape.

Must discharge air and other incondensable gases


3.) Types of Steam Traps

A.) Mechanical:

It is operated by changes in fluid density.

B.) Thermodynamic:

It is operated by the changes in fluid Dynamics.

C.) Thermostatic:

It is operated by changes in fluid Temperature.


A.) Mechanical Steam Trap (Inverted Bucket Trap)




Can withstand high pressures

Tolerates water hammer

Suited for superheated steam lines

Safer because failure mode is open



Trap body must always have enough water

Water seal loss by De-superheated steam

Can be damaged by freezing

B.) Thermodynamic Steam Trap


C.) Thermostatic Steam Trap


4.) Points to be kept in mind while installing Steam Traps

Water hammer:

Condensate picked up by moving steam

Can damage steam trap

Continuous slope in flow direction reduces this


Affects steam trap performance


Helps to remove dirt

Steam locking:

Can occur in rotating machinery

Only float trap has ‘steam lock release’ valve

Pipe sizing:

Correct pipe size – traps affected by resistance to flow

Avoid pipe fittings close to trap – back pressure risk

Air venting:

Important for system warm up and operation


5.) Performance Assessment of Steam Traps

Visual Testing

Sound Testing – Ultrasonic Leak detectors

Temperature Testing – Temperature Guns, Thermal Chalks



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