Steamer Thermostatic Trap

[ectofix]

You asked about a thermostatic “trap”. 

 

Everyone here responded under the notion that you were talking about a trap used on the condensate (outlet) side of some form of heat exchanger employing live steam as a heating medium (vice using heating elements or gas burners).

 

In live steam applications, the steam from a central boiler someplace enters the heat exchanger of the equipment and gives up its heat to HEAT something, then it condenses to water.  A typical “trap” lets that condensate (water) either return back to the boiler to be reheated…or goes down a drain – depending on the setup.

I have allot of steam-heated equipment where I work.  The most common TRAPS we use are either “bucket traps” – made by Armstrong…or “thermostatic traps” made by Sarco:

 

THAT trap performs the function that I’d originally described.  Per the Cleveland service manual:

 

    The water in the boiler is heated to steam.

As steam is generated and pressure builds the air is pushed out through the steamtrap. When steam goes through the steam trap and heats it to 192 degrees it closes.

 

That’s written on page 8 of this manual:

http://download.partstown.com/is-bin/intershop.static/WFS/Reedy-PartsTown-Site/-/en_US/manuals/CLE-24CGM200_spm.pdf 

 

Although I’m not there looking at it, I believe that the brass T-fitting depicted is connected to the pressure gauge and the pressure switch…which controls the heat cycle.  The barb fitting connects to a hose leading to the cooking compartments.

 

CLEVELAND calls it a trap…since it does INDEED trap steam in.  I think a more aptly described as an AIR VENT.  But…they don’t pay me to name their parts.

[olivero]

Lol.

[olivero]

Thank you for the detailed response Ectofix, very much appreciated. 

 

Makes sense though, so pretty much as soon as it senses steam is passing through it (as its getting heated) and the air has gone away, it closes.

 

Makes sense.

[fixbear]

Ecto, it is not primarily a air vent.  However it does vent non condensables.  Being it is placed at the bottom of the main steam line at a low point. It’s primary purpose has to be to drain condensate. Gas venting secondary.  Otherwise it would be placed at the middle or top. Then it would be a air vent.

 

Definition of a Thermostatic Trap is: 

How does a thermostatic steam trap work? Mechanical and thermostatic steam traps basically open when condensate and inert gases need to be removed, and close when all the condensate is removed. The process repeats when new steam is condensed again and ready to be drained. Steam traps work best when sized specifically for the application they are used on. And yes, they have a temp element that when cooled opens to not only veny air out, but to prevent thin wall heaters from collapsing. Run a still once with a thumper over condensing.  Opp’s.  Sucked the copper right in.

[ectofix]

A STILL?  I‘ve only had the very rare experience of indulging in enough sips of that device’s product to keep me away from it…and I live in TN!  That stuff turns me upside-DOWN!

 

I acknowledge that you have a significant edge on me for knowledge and experience of steam systems, fixbear.

 

My experiences with that little trap that olivero asked about has been when I was called to look at a boiler-based steamer that’s not heating.  Of course, I walk up to it, do a cursory look-over of things, then…

 

If that trap is clogged, here’s what happens:

Starting from a stone-cold unit, turn the power switch.  The controls calls for fill.  If that little trap clogged, the unit’s pressure gauge will slowly climb during the FILL cycle. Once the upper water probe satisfies, IDEALLY – the boiler pressure should be 0 psi…since the trap should have vented displaced air.  But, it didn’t. So, by the time the boiler is FULL, the compressed air registers enough pressure to have already satisfied the pressure switch.  As such, the pressure switch won’t call for heat. Usually my next step would be to relieve that pressure by simply entering one of the cooking compartment into a cook cycle.  When that compartment’s solenoid valve opens, the compressed air vents into the cooking compartment, the boiler pressure drops to zero, the pressure switch closes…and the heat circuit energizes.

 

In such a case, I’ve repeatedly found that the trap or its plumbing was the culprit.  In one instance, the boiler was so scaled up that it had clogged the port leading to that trap and I had to chisel through the scale in the fittings AND replace the trap.

 

I HATE scale.  I think I had wore away my fingerprints more than once for having to deal with it.

 

For that trap to also serve for expelling condensate?  I’d never looked at it that way before.  Your explanation makes perfect sense.

[olivero]

Sometimes I think I got this kitchen stuff down pretty well.

 

Then I ask you guys a question and I remember just how little I still know.

 

That’s why I keep coming back.

[fixbear]

ectofix wrote:

 

I HATE scale.  I think I had wore away my fingerprints more than once for having to deal with it.

 

 

Your not alone on this. And today it is unnecessary with the modern electron level  softeners. That separate the minerals out at the atomic level.. No salt backwash or green-sand. They just coagulate and fall to the bottom of the softener for back-flushing.

 

Had a Dishwasher booster that it took 2 prybars to remove the elements from the build up.  And they are never in a easy place.