hydros?

[Rhizophora79]

I was wondering. When you say your tank needs a hydro. Is hydro an abbreviation? Does anyone know what the real word is?

Becky

 

[Corigan]

I was wondering. When you say your tank needs a hydro. Is hydro an abbreviation? Does anyone know what the real word is?

Hydrostatic..

Matt

 

[Snowbear]

I was wondering. When you say your tank needs a hydro. Is hydro an abbreviation? Does anyone know what the real word is?

Becky

Yup, as Matt said, it's an abreviation for "hydrostatic." It involves pressurizing a tank filled with water in a water bath and measuring how much it expands. The water is a safety measure to prevent shrapnel should the tank have a catastrophic failure during the test :11:
If you take the time do a search and filter through the results (I'm working on something else right now or I would provide you a link ), you should find a whole pile of information on the subject....

 

[Ontario Diver]

HYdrostatic testing is a test to determine the elasticity of the tank. The concept is that any tank that gets pressurized acts like a ballon. It expands more as the pressure goes up. And just like a ballon, when the pressure is released - the tank shrinks but not (immeadiatly) to its original size.

The test involves filling the tank with water and then pressurizing it to the test pressure (5/3 or 3/2 working pressure as defined by DOT or TC). Water is used because it doesn't compress like air does - not for safety ( we use a blast proof pressure vessel for that ) There are a number of ways that the expansion can be measured, by doing the test inside a water jacket attached to a measuring device, by weight, or by measuring the amount of water pumped in and then out.

The tank must return to within 5 or 6 % of its origninal size. A typical AL80 will expand about 64 cc and then shrink to 2 cc over its original size. The big big cylinders will expand to 350 cc - about the same size as a can of pop.

A full test will ensure that the tank does not stretch too much and then shrinks back enough.

I hope that this helps.

 

[oxyhacker]

Water is used for several reasons (faster tank pressurization, more accurate measurements) but safety is still probably the top reason on the list - blast proof enclosure or not, an air-filled HP tank letting go would not be a happy event!

But do you really use blast proof vessels in CAN? The ones here look like they might be, but are not - they have low pressure rupture ports that burst to release the pressure in the event of a tank letting go.

Water is used because it doesn't compress like air does - not for safety ( we use a blast proof pressure vessel for that )

 

[Ontario Diver]

Water is used for several reasons (faster tank pressurization, more accurate measurements) but safety is still probably the top reason on the list - blast proof enclosure or not, an air-filled HP tank letting go would not be a happy event!

But do you really use blast proof vessels in CAN? The ones here look like they might be, but are not - they have low pressure rupture ports that burst to release the pressure in the event of a tank letting go.

We are supposed to use a vessel that can control fragments. There is a rupture port as well for pressure relief. (and a mop and clean undies nearby!)

TC does not allow air to be used for hydro testing. All three methods (weight, water measuring, and water jacket) all use water.