FILTERS & STRAINERS - MECHANICAL STEAM TRAP PDF Print E-mail
Written by Norrie   
Tuesday, 11 May 2010 19:22
Article Index
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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1. THE MECHANICAL STEAM TRAP (Float Type)

The Float type steam trap consists of a chamber having inlet and outlet ports. The chamber contains a stainless steel ball-float connected by a lever to the inside of the chamber wall. In the body of the trap, the outlet port has valve seats fitted to accommodate a valve plug which is fitted to the lever between the float and the chamber wall.

When the trap is empty, the ball float is down and the outlet valve is closed. As condensate (water) enters the trap and forms a level, the ball begins to float and rise with the rising level.

At a pre-set level the rising lever actuates the valve plug and opens the valve. Condensate passes out of the trap, the level falls and the valve closes down. In this way, the level of condensate is controlled and no steam loss is incurred. This type of trap works well with heavy or light condensate loads.

There is however, one point to mention, steam contains small amounts of uncondensible gases and these can build up in the trap and cause loss of efficiency. The trap is therefore fitted with a vent valve at the top to periodically release these gases. This type of steam trap has the disadvantage of possible freezing in winter conditions and can be damaged by water hammer (previously mentioned).
(See Figure : 28)