OPD valves... FAILURE!!

[Silver Bullet]

OK, here's one for ya'll.

Got a new OPD valve installed this time last year (give or take) on my 30#'er. It now seals on "off" and seals on "full open" BUT, leaks like a tire with a railroad spike in it! (Been there too!)

Has anyone experienced this problem with the (uh hem) "ultimate " solution to over-filling POS valves?

Oscar


PS The old valve was 10 yrs. old and didn't leak a FUME!!!

[wahoonc]

Oscar,
Here is a link, http://www.mantank.com/safety/scg_valves.htm There were some valves out there that had been made in China that were very inferior, bad enough to the point that I believe that a recall was being considered and the manufacturers that were using them had to stop using them immediately. It may be possible that you got one of those?

Aaron

[Silver Bullet]

Bet I got one of those "cheepos" here on the "border" I'll investigate Fri., after TURKEY!!!!

Thanks for the info Aaron,



Oscar

[53flyingcloud]

wahoonc

Manchester Tank would like to assure our customers, distributors, and industry members that the OPD/Valve combination we installed into our cylinders using the brass SCG valve and a Manchester approved OPD are SAFE, RELIABLE, and FIT FOR USE. Going forward, the SCG brass valve portion of our Valve/OPD combination we use will have a green label inserted into the handwheel, in order to differentiate our valves from those valves in question.

In other words, the ones in question are COLORED RED..
For what it's worth..

Recently there have been announcements warning our industry of potential safety concerns about SCG Valves manufactured in Thailand.

ciao

[wahoonc]

That is my understanding, also it is apparently just the one brand of valve, and there are quite a few different ones out there. As soon as I get one of my tanks completely empty, it is going down for a new valve and a recertification. I have dual 30# aluminum and they are worth redoing. I am planning on asking to see the valve prior to installation, and I will point them to this article as well.

Aaron

[53flyingcloud]

Thanks for the info guys..I'll be sure to check out my new tanks the next time I'm down South..
Was there just last week, had I known then...
"Happy Holidays to one and, ALL.."

ciao

[Silver Bullet]

That info will accompany me to the servicer to which installed the valve.

Oscar

[McMullen]

Its normal operating procedure on any propane valve to open all the way and close all the way. the packing in the valve is not designed to take the gas presure steady. the actual seal is on both ends of the valve. This is also true on Acetyline valves and oxygen valves. Some times you can just tighten the packing seal nut. At least on the old tanks. I havent used the newones yet. Mac

[Silver Bullet]

Stem seals should hold the pressure. If this was not true then household faucets would be full open or full off (40 psi, I know), air compressor regulators (120+ psi) hold without stem failure, and acetyline and O2 regulators have adjustable valves to regulate the #'s for welding or cutting. Bottom line, ALL stem seals should hold the pressure designed for the application intended.

On the old style valve I could turn it 1/4 turn and no leaks, as I said before, it was 10 yrs old.


Oscar

[McMullen]

Gotta disagree silver bullet. You take your stem out on any regulator and you will find that there is no seal at all . regulators only have presure on one side of a diaphram, unless they are diving regulators and I doubt if they have stem seals. But anyway we are not talking about regulators. we are talking about gas valves. You pickup a propane instruction manual at your local trailer supply and read what it says about propane valves.. Even a water valve seats at the closed end of the stroke and takes the presure off of the stem seal. and most water valves will leak around the stem if you stop the flow of water with a hose valve or some other way to presurise the stem seal. If you turn on your propane tank just part way you rely on the stem seal for a long period of time and eventualy it will start to leak. If you open it all the way the presure is against the end seal and thats what it is desghned for. Mac

[McMullen]

Of Interest


Basic Facts About LP-Gas

Pounds per gallon 4.24
Specific gravity of gas 1.50
Specific gravity of liquid 504
Cu. ft. gas per gallon liquid 36.38
Cu. Ft. gas per pound 8.66
BTU per gallon 91,502
BTU per pound 21,548
Dew point in degrees F -44F
Vapor pressure at 0º F .31 psi
Vapor pressure at 70º F 96 psi
Vapor pressure at 100º F 127 psi
Vapor pressure at 110º F 230 psi
In cold climates, in order to keep vaporization of LP-gas at the highest level, keep the fuel levels above 50%.

Average LP-Gas Capacities In Cylinders

LBS. GALLONS BTU
5 1.18 107,903
10 2.36 215,807
11 2.59 237,387
20 4.72 431,613
30 7.08 647,420
40 9.43 863,226
The above capacities allow for the 20% vapor space on each cylinder.




Conversion Table

Gallons to Liters (1 Gallon = 3.785 liters)
Fº to Cº (Fº = 9/5 Cº + 32º)
11” Water Column = 6 1/4 oz. Psi.
27.7” Water Column = 1 lb. Psi.

Mac