Piston Tank in a wet hull

[subarmada]

Have any one used a piston tank in a wet hull submarine? The reason I ask is that a piston tanks create pressure inside the WTC/hull once is actuated to admit water inside. In a dry hull this is not a problem since it has a lot of space and the pressure is low but in a dry hull the pressure may be high.

Any one has some experience with this situation?

Ricardo

[JWLaRue]

Sure! I've been using one

Sure! I've been using one on my OTW Seehund. The dive module is constructed from the usual clear tube but the endcaps are held in place with three tie rods that run the length of the module. This keeps everything nice and tight during those 'over' pressure conditions.

Here's a photo of the module:



I'll be glad to any questions!

-Jeff

[subarmada]

I see in the picture

I see in the picture that you are using bellows for the push rods. Have you try that WTC set up with subtech seals?

What is the diameter and length of the WTC?

Is the piston tank capacity 1/2 liter?

Thanks
Ricardo

[bigdave]

Hi Ricardo,
The Subtech seals

Hi Ricardo,
The Subtech seals are a one way cup seal. They are meant to hold back pressure in only one direction. You could use two back to back or just replace the cup seal with a O-ring. I have done both and it works fine.

Jeff,
Don Osler and I built a system like this for his Albacore about 5 years ago. It works great but does develop a lot of pressure inside of the cylinder.
Don's was a two cylinder system. One 4" and one 3" Lexan tube. At first we only had stops on the ends to keep the end caps from flying off. It worked till one test he was taking on ballast to dive and the pressure got so great it popped the center end cap off by the entire cylinder lifting up in the middle from the pressure on the end caps. It was really cool to see. We heard a loud POP!! and down she went. Don was not so impressed. We have since added a center strap to prevent this. I will ask him to post a photo of his cylinder. BD.

[bigdave]

Here is a photo of

Here is a photo of Don's cylinder.

[JWLaRue]

The dive module that's in

The dive module that's in the Seehund is made from a 110mm tube and has an internal volume slightly more than twice that of the Engel piston. This yields a maximum 'over pressure' of roughly 2 bar when fully submerged....not a lot to deal with. But I still rely on the tie rods to hold everything together.

The piston is a stock Engel piston that is 825ml in size.

I used the bellows specifically for the reason that BigDave points out regarding the cup seals.

-Jeff

[scaleships]

I've been using pistone tank

I've been using pistone tank on my sub AKULA.
The WTC 110mm dia. Piston tank 1L in size.
The piston tank does develop a lot of pressure inside of the WTC. Your WTC have to have a free volume in 2 times more than your piston tanknk. And you have to make attachment for end caps.

[k225]

I use a Engel Piston

I use a Engel Piston tank in my Robbe Type XXI the seals are the weak point what are you guys using?