F&T Float 'Impoded?'

Steamhead

change the seats on those 30-pound traps to 15-pounders when you rebuild them and you should be OK.

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Alaska Joe

F&T float imploded

I just spent the past few days doing maintenance on steam traps for the first time. The traps that seviced the farthest unit heaters on both ends, were found with floats that were imploded or caved in. Its a 15# system, and the end of line traps were 30# traps. When I opened them up, it seemed that they never were in operation, like new. (and full of condensate)My boss had no reply when I questioned why? All the other serving traps were 15# (Sarco F&T 3/4) What kind of action could cause the floats to cave inward like they did?

Unknown

Imploded Float balls

The float ball did not impload. The trap was subjected to water hammer.

A 30 psi rated trap is rated the same as a 15 lb trap. Both trap bodies will with stand 125 psig. The float balls in the trap are made of the same materials. The difference in the traps is the capacity to remove water from the steam line it serves.

The thirty pound float trap has a smaller orifice than the 15 lb trap. Therefore at operating steam pressure the thirty pound trap will release less water.

Example:

assume both steam traps are 1 1/4"

The 15 lb rated trap will release 2430 lbs of water at an operating pressure of 15 PSIG

The thirty pound steam trap operating at the same pressure will release 1680lbs per hour.

This happens because the orifice in the 15 lb trap is .312 and the orifice in the 30 lb trap is .228 ID.

Since the thirty pound trap releases about 800 lbs of water per hour less this water remains in the steam piping system.

When the steam cycle re-starts the steam flowing about 40 miles per hour propels the water to the end of the steam main. When the water reaches the end of the main water hammer occurs and it crushes the float ball.

This example given is based on the premis that the steam system has no other problems that cause condensate water retention or boiler water carry over.


Jake.

Possible cause of the water hammer is

Alaska Joe

Thanks Jake!

I want to work with you, you've got answers and explain them perfectly. Thanks for the lesson, I might be able to pay for it with fruit cake! Till I'm better paid....

Chauncey

40 miles per hour may not sound fast

but consider that 40mph is the speed that those car crash tests are conducted at. C