FILTERS & STRAINERS - THERMO-DYNAMIC STEAM TRAP PDF Print E-mail
Written by Norrie   
Tuesday, 11 May 2010 19:22
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FILTERS & STRAINERS
FILTERS
STRAINERS
STEAM TRAPS
MECHANICAL STEAM TRAP
THERMOSTATIC STEAM TRAP
THERMO-DYNAMIC STEAM TRAP
EJECTOR SYSTEMS - INTRODUCTION
EJECTORS AND EDUCTORS
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3. THE THERMO-DYNAMIC STEAM TRAP

This type of steam trap, when installed, has a strainer fitted into the line upstream of it, to remove solid particles of scale ..etc. As condensate enters the trap, through the inlet pipe with the steam pressure behind it, a metal disc is forced upwards into a small chamber and the condensate passes under the disc into the outlet pipe.

The velocity of the water passing through the trap is low, even when the pressure is high. This is due to the density of the water being high compared to that of steam and the fact that, within the trap, the fluids pass through an angle of 180°.

When all of the water has been displaced, steam begins to flow. The greater velocity of the steam below the disc and the sudden change of direction, causes a pressure drop under the disc which pulls it down onto its seat and stops the steam flow.

The steam pressure in the chamber above the disc will be the same as the line pressure thereby holding the disc on its seat. When the steam above the disc cools and condenses, the chamber pressure falls and the disc is forced upwards again by the line pressure.

If only steam passes into the trap, the above process is repeated with a small release of steam until the disc drops again.

This type of trap is recognized by the quick hiss of escaping steam every few seconds.

(See Figure : 30)

THE THERMO-DYNAMIC STEAM TRAP


Figures: 30