Ball Valve: Is poly any better than PVC

[gwalker Senior Member Find all posts View Profile Close gwalker]

Stainless steel and brass are much more expensive than polypropolene and PVC.
I've heard bad reports about PVC but not on Poly.
G

[zigparacingtadpole Senior Member Find all posts View Profile Close zigparacingtadpole]

Re: Ball Valve: Is poly any better than PVC

G'day,

PVC stands for Poly Vinyl Chloride, Poly is just a contraction of this.
I dismissed the idea of using PVC or Poly mainly because of the heat. They should be immune to the chemicals but the heat may cause a problem.

Rgds

Adam

[Chev28 Senior Member Find all posts View Profile Close Chev28]

Re: Ball Valve: Is poly any better than PVC

Have a look at PEX if you are concerned. It is the poly pipe that plumbers use in houses for hot and cold water.

See

http://www.auspex.com.au/AuspexPipe/

[Chris Senior Member Find all posts View Profile Close Chris]

Re: Ball Valve: Is poly any better than PVC

Hi all
The use of short names in plastic fittings or pipes is one to be taken with a grain of salt
Poly refers to polyethylene in the plastics industry either HD or LD, high density or low density
If you are a plumber, poly means the new type of plastic piping for houses, some also refer to poly as to the PVC type of plastic used commonly around any building for sewerage which is rigid or unplasticised PVC
PET is another poly, that is the material clear plastic soft drink bottles are made from, black poly is pipeline material used in mines to recycle or bring in water
So please, treat any thing with "poly" as a reference with caution, it does not necessarily means what you had in mind
Cheers
Chris

[Guest Close David]

Re: Ball Valve: Is poly any better than PVC

I bought a bunch of black plastic fittings the other day to use on a dumpster sucker and was thinking of using them on my processor.
I have read on other sites the warnings about plastic fittings going soft and I couldn't see how this would happen at 100oC let alone bio processing temp of say 70 and under. The softening theroy didn't make sense to me because if they use them on domestic hot water plumbing that reaches 70oC, with a decent pressure on them as well, there has to be a saftey margin that would make 100o within tolerance.

Reading this thread I thought i'd go see that the deal was with a test. I got one of the black plastic plumbing fittings of the type they use in houses and another fitting used in irrigation.

First test, hot water out of the tap. I have my thermostat turned right up on my water heater as the system isn't as big as i'd like and this effectively gives more hot water. A minute of so under the tap and I have a hot sink and a steamed up window but no difference in the fittings at all.

Next test, boiling water from the jug. Emptied anout a litre and a half over each fitting and no detectable difference.

3rd rest, boil the buggers for a good 5 minutes in a pot of water on the stove. This time I thought I got a result. Only notice a few minutes later when I emptied the pot and put it away and went to squeze the fittings again did I realise that rather than them getting softer, I was just squeezing them harder trying to get them to move.

My conclusions would be that I will have no problems using plastic fittings on my processor because at the temps the thing is going to operate at, it makes no difference whatsoever (as I suspected all along) to the strength of the the plastic.

I have no idea of exactly what form of " Poly" the fittings I have are made from, I got them from the local bunnings and they are black, but I would suggest that other people could spend $4 on a sample fitting they want to use and conduct a pot of boiling water test themselves to see if what they are thinking of using is up to the task.

[casper151 Biofuels Forum Newbie Find all posts View Profile Close casper151]

Re: Ball Valve: Is poly any better than PVC

Yeah, I haven't had problems with the PVC fittongs from Bunnings.

I do't run hoses of the stuff but that Xlinked Polyethelene (PEX) that plumbers use sounds the go.