Tuesday, September 06, 2011

Safety First?

I tried pumping air into my PlaySport depth tester, but didn't see any change in the pressure gauge as I did so. That concerns me, as I wonder if I would be able to detect the pressure buildup before it reached explosive levels. As someone noted in an earlier post, the ABS pipe becomes a grenade at high enough pressure levels.

Below is a possible solution to the worry. 30 PSI is 2 ATM, equivalent to 60' underwater. If I used a pressure relief valve on my PlaySport depth tester, I wouldn't need an air pressure gauge.


8 comments:

tim eisele said...

Is the pressure gauge on your bicycle pump? I've always had trouble with those. About half the time they are off by as much as 20 psi in either direction.

If it is, maybe you could test it by connecting it to the tire of your car and giving it a few pumps, to see if it registers pressure then.

And, you could always use one of those cheap extending-stick tire pressure gauges to check the pressure in your chamber after a few pumps.

K T Cat said...

Tim, I've got a pump that's operated from my car's cigarette lighter. That's as big a pump as I was willing to try at first. Like you said, the gauge on that is pretty inaccurate.

What I need to do is find someone with a real compressor and a long hose and inflate the thing around the corner of a building so if it blows, no one gets hurt.

tim eisele said...

Here's a thought: you're going to 30 PSI, and the average tire gets inflated to 35 PSI, right? And the volume of a car tire is quite large compared to your pressure vessel. So, if you just connected your pressure vessel to one of your car tires, it should inflate just to the tire pressure and then stop. There is then zero chance of ramping up the pressure to some outrageous level. The only sticking point would be coming up with a two-ended hose for transferring air out of the tire and into the vessel.

K T Cat said...

Brilliant!

Mostly Nothing said...

The pressure gauge is not going to give you any kind of accurate reading with a schrader valve (normal car valve). For a pumps gauge to have anything close, you would have to be using a presta valve (higher end bicycle).

The schrader valve is not very precise. And the hose connectors for it are not going to get a good connection for you.


If you want the pressure gauge to give you a decent reading, pull the spring out of the valve of your vessel. Time how long it takes for the pump to get the gauge up to the desired pressure. That will get you close.

K T Cat said...

Thanks, MN! I'm thinking that Tim's idea of hooking the vessel up to a car tire will solve all problems.

small business web design said...

Is the pressure gauge on your bicycle pump? I've always had trouble with those. About half the time they are off by as much as 20 psi in either direction.

small business web design said...

Is the pressure gauge on your bicycle pump? I've always had trouble with those. About half the time they are off by as much as 20 psi in either direction.