Testing Empty Housing

[KeithG]

Even if a container remains sealed, the same number of gas molecules in a sealed container does not always mean equal pressure.

We are discussing rigid sealed containers. Not sealed containers. A balloon is a sealed container.

 

[caruso]

Can you provide a link that would help us understand what you mean by "negative pressure"?

negative pressure - Google Search

 

[KeithG]

negative pressure - Google Search

And maybe a link that explains how it affects a sealed rigid container?

 

[caruso]

And maybe a link that explains how it affects a sealed rigid container?

I think you forgot to thank me for providing the link that you asked me for, that's ok I get a lot of that.

As far as your next request, such a link does not exist. We both know that as long as the sealed rigid container is not compromised the pressure within it will not change as it is brought to depth.

 

[KeithG]

I think you forgot to thank me for providing the link that you asked me for, that's ok I get a lot of that.

As far as your next request, such a link does not exist. We both know that as long as the sealed rigid container is not compromised the pressure within it will not change as it is brought to depth.

Agreed. So it does not matter what is in the housing.

Do you concur?

 

[caruso]

Agreed. So it does not matter what is in the housing.

Do you concur?

As long as the housing is strong enough then I concur. However, in the case of a housing that is not designed to withstand the pressures that it will be under when it is brought to depth, which would be greater in the event that the housing is completely empty, that housing may flex inward, crack, break or have it's seal compromised.

 

[KeithG]

As long as the housing is strong enough then I concur....

Awesome. Taking down an empty normal housing is just fine.

There may be some use in starting a thread to discuss the separate topic of non rigid housings as there are several brands of "dive camera zip lock baggies".

 

[Chris Ross]

Even if a container remains sealed, the same number of gas molecules in a sealed container does not always mean equal pressure.

The only way pressure can change is for volume to change or the temperature. The effect of temperature is very small.

You can change to volume if the housing collapses or flexes inwards and that would cause the pressure inside to increase as the volume would get smaller. The pressure increases by the ratio of the volume of gas present in normal and flexed condition. If there's a camera in the housing the actual volume of gas is less so the pressure will increase more due to the flexing assuming it flexes the same amount which will assist the housing to resist the flexure. If the camera makes the housing more rigid it may flex less and will likely approach the pressure increase seen with an empty housing. Most likely is that as long as it doesn't collapse it will just reach a different equilibrium.

I can't see why any housing would be designed using the camera as a structural element, the only reason to do so would to save material. If you want to make the housing stronger all you need to do is add a thin rib, even something as simple as making the rim of the viewing window a touch thicker to give it he necessary strength, the extra material required is minimal. Pressure vessels designed for external pressure are often ribbed to give them the necessary rigidity to withstand the pressure. It would be far easier to design the housing to withstand pressure when empty.

 

[caruso]

I can't see why any housing would be designed using the camera as a structural element, the only reason to do so would to save material. If you want to make the housing stronger all you need to do is add a thin rib, even something as simple as making the rim of the viewing window a touch thicker to give it he necessary strength, the extra material required is minimal. .

You clearly have never ordered anything from China.

 

[tursiops]

You clearly have never ordered anything from China.

Caruso, you are making a big deal about how having the camera inside is an integral part of the strength of the (rigid) housing, hence your conclusion that an empty (rigid) housing will/could/might implode. Can you give any evidence that this is a problem, or is it just speculation/argument?