Thursday, July 30, 2009

coleman check valve

I dissassembled a Coleman "suitcase" stove last week to get to a problematic part. Most parts on a coleman are trivial to service. The exception is a small object buried in the fount called a "check valve".

There's not an easy way to get to it, it can take a special $50 tool, and can get very, very stuck. Many people go their whole camping lives without having to change one of these doodads. I got mine out and replaced it today and cranked it up. Runs and holds pressure like a champ.

Here's how it works. Consider what happens when you pump up a Coleman fuel gear:

* release the plunger by rotating it a turn or so CCW.
* pump until you reach desired pressure
* lock the plungber back in place by rotating it CW until you feel it seat.

When the plunger is screwed into place it prevents air from leaking out.[0] But what keeps the air from leaking out after the plunger has been opened? That's the check valve. It contains a ball little opening, blocking outward air movement. The screwed-in plunger and the check valve are the "belt and suspenders" system that keep the explosive fuel/air mix inside the gear where it belongs.[1]

Speaking of which, I just called Atmos to report a possible gas leak around our meter out back. I might be imagining things; it's either faint or not there at all. But they are apparently on the way. I don't think we are in great danger of blowing up. But if you hear sirens tonite and I don't post anymore...

[0] more correctly, the air stem it's connected to prevents air from leaking out, but you get the idea.
[1] there's a third safety, in a way. The check valve sits in fuel but has a snorkel like a Hummer, so in case it depressurizes only air comes shooting out the hole in the plunger, not fuel.

No comments:

Post a Comment