Thinking of using PVC pipe for air?

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SteveHGraham
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Re: Thinking of using PVC pipe for air?

Post by SteveHGraham »

Someone explain the chlorine filter story.
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NP317
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Re: Thinking of using PVC pipe for air?

Post by NP317 »

I plumbed the compressed air in my new shop with commercially available air hoses. It was easy and works well.
The longest run is 50 ft. with 3/4" diameter hose.
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tomjaksa
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Re: Thinking of using PVC pipe for air?

Post by tomjaksa »

The chlorinator kept running without the 15kw filter pump there to provide flow. A by product of salt chlorination is Hydrogen gas.
It filled all the pipework with hydrogen gas!
They bypassed the safety switches to keep it running

And it was one of the top Universities in the country.
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SteveHGraham
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Re: Thinking of using PVC pipe for air?

Post by SteveHGraham »

They bypassed the safety switches! And they weren't just using PVC for air...they were using it for an explosive gas! That's Darwin territory.

In fairness, I would imagine hydrogen would also blow iron pipe into smithereens.

Not surprised that it happened at a university. Common sense and the kind of sense that helps people get good grades are not always found together.
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SteveM
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Re: Thinking of using PVC pipe for air?

Post by SteveM »

SteveHGraham wrote:In fairness, I would imagine hydrogen would also blow iron pipe into smithereens.
With a significantly higher mayhem potential!

Steve
John Hasler
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Re: Thinking of using PVC pipe for air?

Post by John Hasler »

SteveHGraham wrote:They bypassed the safety switches! And they weren't just using PVC for air...they were using it for an explosive gas! That's Darwin territory.

In fairness, I would imagine hydrogen would also blow iron pipe into smithereens.

Not surprised that it happened at a university. Common sense and the kind of sense that helps people get good grades are not always found together.
You wouldn't want to use iron pipe around chlorine.
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SteveHGraham
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Re: Thinking of using PVC pipe for air?

Post by SteveHGraham »

So it's not just the hydrogen that goes through the pipes?
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Steggy
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Re: Thinking of using PVC pipe for air?

Post by Steggy »

tomjaksa wrote:And it was one of the top Universities in the country.
There's quite a difference between being educated and having common sense.
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John Hasler
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Re: Thinking of using PVC pipe for air?

Post by John Hasler »

SteveHGraham wrote:So it's not just the hydrogen that goes through the pipes?
I don't think hydrogen was supposed to be in the pipes at all. It isn't clear what was. If the pipes were supposed to be carrying chlorine it's obvious why they used plastic (bypassing the safeties and running the system without filters was still stupid, of course). I suspect that the system was properly engineered but improperly operated. I also doubt that any of the university faculty were involved (or even knew about it). Professors don't usually do plumbing.
tomjaksa
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Re: Thinking of using PVC pipe for air?

Post by tomjaksa »

The chlorinator makes chlorine from salt in the water. It runs plumbed in the return line of the filter plant. The small amounts of hydrogen are carried away with the water. The main filter pump stopped, water was not being carried away. They bypassed the flow sensor. It was like that for about seven days. The hydrogen gas had nowhere to go,
As for the faculty i do not know..... The maintenance staff was warned not to do it. The last thing i said to them in the reply letter was for them to ask on of the "proffies" why they should not do it.
Luckily i had a copy of the letter to show them that i said they must not do it When it came to paying for an new filter plant.
And all that to save some bucks on granular chlorine.
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SteveHGraham
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Re: Thinking of using PVC pipe for air?

Post by SteveHGraham »

Now I know what you're talking about. When I was a kid, my dad had a gadget called a Genie-Chlor. It was an electrolysis machine that turned salt into chlorine gas. It sat next to the pool pump. It was supposed to save us the hassle of adding chlorine tablets to the water.

It turned out to be pretty worthless. The seller kept coming to the house and putting bags of salt in the pool, but it never lived up to the hype. I would guess the problem was that chlorine gas evaporated and left the pool. To make it work, you would need a constant supply of chlorine salts that could be broken up to free chlorine.

PVC was not a problem for this machine. The pipes were was carrying chlorinated water, which works fine with PVC, and it never got the opportunity to fill the plumbing with hydrogen.

The Internet says PVC works fine carrying chlorine gas below atmospheric pressure, but that pressurized chlorine will make it porous.
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John Hasler
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Re: Thinking of using PVC pipe for air?

Post by John Hasler »

> I would guess the problem was that chlorine gas evaporated and left the pool.

It would be used up as it reacted with organics in the pool as well (but that's what it is for).

> To make it work, you would need a constant supply of chlorine salts...

Sodium chloride: table salt. Water-softener salt or feed salt from the feed store would work fine.

My high school had an indoor pool that was heavily overused. To keep the E. coli count within legal limits without changing the water as often as they should have they chlorinated the hell out of it. Of course they also were too cheap to adequately ventilate the pool so every student got to breath chlorine gas for about half an hour every week until they fulfilled their swimming requirement.
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