using a water filter as a canister

[el-ninio]

The coffee machine tecnision came by today, and left me with a water-filter case that looks like an exelent starting point for a canister light. The case is 10" deep, about 3.5 - 4" internal diameter, and acording to the technision shold be able to withstand at least 8 at. it's made of some thick transtenet plastic, and the top scrows on and seals with an oring. the top is made of some white plastic, and has two holes with scedual(?) so you can screw in and tighten some external pipe or whatever.

It's still got to be checked under pressure, but it seems like an excelent start for bulding a canister. if its seal will hold, it's a cheap and easy to assemble. The power line and the switch can be fited withint the (provided) plastic connection mini-pipes, and then apoxed into place so they don't leak.

attached is a picture of a simular case.

 

[el-ninio]

rated to 10.5 AT (working pressure) and about 35 bar bursting pressure.

http://www.unit-industrial.com/HF.htm

 

[ScubaToneDog]

But their pressure rating is for internal not external psi. Will that make a difference? It might.External pressure on the canister may cause the threaded end to crush and/or warp allowing it to leak. Some sort of internal renforcement ring on the threaded end may prevent that.

Just a heads up thought.

Let us know how it comes out....

 

[pipedope]

strength which ever way you pressureize them.

One way to find out for sure.

Try it.

These are pretty cheap.

Now you went and got my wheels turning again.

 

[FredT]

Internal load is handled by wall tension, failure is usually a straight tenslie failure, and as such is very preditable.

External load is a compressive load, with failure normally due to buckling. Buckling can be a much reduce pressure rating. Typically on long empty nonmetallic cylinders it'll happen at 1/3 to 1/2 the tension rating unless internal stiffeners are added. Buckling is VERY much a geometry driven event. Even a slight bend, ding, or chip can precipitate buckling at much lower than even normal buckling loads.

I have an instrument in a SST pressure vessel of aobut a gallon internal volume that would fail by buckling at about 800FSW. When we got instruments back that had "gone deep" you could see every resistor and inductor on the PC board, through the metal. The housing acted like a vacuum pack blister. The failure happens fast enough at crush depth that it's easily audible on a hydrophone.

FT

 

[Padipro]

Load some weight in the thing and take it with you on a dive, say in a catch bag, and see if it can handle the pressure. I've done this with both the camera housing and the canister light prior to actually installing anything in them. I found a small leak on the camera housing near one of the controls on the test dive possibly saving the camera from damage.

Scott

 

[el-ninio]

in a teporeral way? The top has two opnings for the water, both threded, and I have matching tubes that are desighend for connecting to a waterline. I will try to drop in at some local supplay shop and see if they have plugs with the right threding, or even betal boalts that could match. To this I will add tuflon coating, and see if it works?
any other ideas?

 

[FredT]

Install Pipe plugs, or even a short hose with a rod inserted and hose clamped off. Teflon tape is a good sealing device for pipe threads going into a plastic housing. Be careful not to over torque the fittings. Pipe threads are generally tapered and will split many plastic housings if overtightened.

FT