Cleaning hydraulics rapid question

oilyspanner · Unread post by **oilyspanner** » 28 Feb 2005, 21:11

Ah! the ideal gas equation now that takes me back, still dont fancy using petrol as hydroflush though, at a push perhaps diluting LHM with some kerosene or even white spirit, though I would not run it for long (I had Hydraflush in for 2k miles approx)as the lubrication would be suspect as well as potential flammability issues.
Stewart

FrenchLeave · Unread post by **FrenchLeave** » 28 Feb 2005, 21:33

Sorry if I came across as a bit of a pedant, I have to say that I find the general level of knowledge and information on this site is awesome.

BonceChops · Unread post by **BonceChops** » 28 Feb 2005, 22:23

Nitrogen is the usual gas that hydraulic accumulator bladders are filled with. Spheres are basically an accumulator so it probably seemed like a good idea to stick with nitrogen when first making spheres.

oilyspanner · Unread post by **oilyspanner** » 28 Feb 2005, 22:43

Nitrogen is cheap too. big commercial bottles come very reasonably priced.
Stewart

FrenchLeave · Unread post by **FrenchLeave** » 01 Mar 2005, 18:40

I know we're getting a bit off subject, but I'm still intrigued by the reason why Citroen used nitrogen in their spheres. It certainly wasn't for fire suppression and as for the comments about springing rates, water vapour in air and cheapness, it doesn't sound convincing. After all, air is used as the springing medium in the oleopneumatic legs on aircraft undercarriages and they fly at 11000 metres (temperature -56 dec C.). The air is dried before charging by passing over silica gel crystals.

406 V6 · Unread post by **406 V6** » 01 Mar 2005, 19:32

If i'm correct it also has to do with the sphere's membrane permeability to nitrogen, wich is low.
Darn, i didn't expect this simple question to become academic[:P]

madasafish · Unread post by **madasafish** » 01 Mar 2005, 20:15

Nitrogen does not dissolve easily in liquids. Oxygen does. Once you get a gas dissolved in a liquid its pressure sending properties diminish (hence brake bleeding).
Also oxygen reacts with rubber nitrogen does not.
My best guesses...

JohnW · Unread post by **JohnW** » 02 Mar 2005, 22:15

I'm sure that there's been a thread about nitrogen in spheres, a year or so back. It is typically, if not universally used in inflatable rubber packers for borehole testing, and I've always presumed it is because it doesn't react with the rubber and is available dry. With PV=nRT operating, it wouldn't be different from dry air in "springing" in my view either.
As for petrol or diesel in the system to clean it out..... Aaarggghhh! I've seen a pinhole leak in a high pressure line and, if you want a really good explosion, try it with a flammable liquid. That's why fuel injection works so well in the combustion chamber....
JohnW