What are steam traps and working of a Ball float type steam trap?

##What is a steam trap?

Steam traps are a type of automatic valve that filter out condensate and non-condensate gases such as air without steam escape. This self-contained valve automatically drains the condensate from a steam-containing enclosure while remaining tight to live stream.

The steam trap automatically opens and closes to discharge the condensate and it can also limit the discharge of the condensate.

There are different types of Traps:

  • Mechanical trap

  • Thermostatic traps

  • Thermodynamic traps


Ball type steam trap:

ball type steam trap

A simple stem trap is shown above, which is a mechanical ball type steam trap. This type of trap consist of a float system.

The steam gets to pass through the inlet, the condensate water or air get condensed at the bottom of the chamber. The steam flow out through the air vent capsule. As the amount of condensate increases the float raises up because of the buoyancy force. When the level of the condensed liquid increase above a particular level, the opening attached to the float opens to release the condensate. The condensate level never lets 's go below the opening line as the float close the opening by that. If the condensate goes below the opening level there is a chance to mix the steam with the condensate. Thus the steam is passed through the air vent and the condensate is passed through the bottom opening hence we can say the condensate is separated.

##Advantages of a Ball float type steam trap:

  • Continuously discharges condensate at steam temperature. Can be used where the rate of Heat Transfer is high for the area of heating surface available.

  • It has a large capacity for its size.

  • The trap can release air freely as long as the air vent is fitted.

  • It is able to handle heavy or light condensate loads equally well and is not affected by wide and sudden fluctuations of pressure or flow rate.


  • Float type trap can be damaged by severe freezing and the body should be well lagged.

  • If a trap is subjected to a higher differential pressure than intended, it will close and not pass condensate.