Solid Bar Yoke

[luis]

Luis, it was early and my body had gotten out of bed but my head had not. Reguarding the old yokes, the Navy used these on their 3000 psi aluminum doubles long before the stronger yokes came out.

That is what I figured, but I wanted to clear it up for everyone’s benefit.

[luis]

Luis,

Question for you. With this setup, as long as both valves were turned on, wouldn't the force on the yokes be balanced out?

Mike

It doesn’t mater whether one valve is open or both. If there is any pressure in the manifold, both yokes will see the same tension (actually all three, including the regulator or filler hose). The tank bands are not really intended to hold the pressure thrust / force.

[pescador775]

Yes, I had not considered that. That explains why those old bars don't blow O rings more regularly than they do. The forces act on the opposite end through the hole and these forces should be equal and opposite in the bar manifold. The forces would try to push the tanks apart but that would be resisted by the bands. I don't know exactly how much difference that would make. Normally, the yokes stretch about 0.007 at 3000 psi. With Navy style bands, I doubt that the tanks would move at all, almost certainly not 14 thousands.
Pesky

Luis,

Question for you. With this setup, as long as both valves were turned on, wouldn't the force on the yokes be balanced out?

Mike

[pescador775]

The force exerted on the A clamp is determined by the area inside the valve O ring which is about 1/2 inch and by the pressure, 3000 psi. I put the force at 589 pounds.

[duckbill]

I don't know about 3000 psi, but concerning the yokes:
The center-to-center spacing of my doubles bands are just the right distance to actually put a fair amount of compression on the "bar yoke" (i.e. Twin crossover). This means that the crossover is under compression. The actual yokes see very little effect from air pressure. I could almost run the doubles with the yokes loose (Haven't tried it, and wouldn't recommend even testing the theory).

My point (as far as worries concerning the pressure rating of the yokes on a setup such as this) is to get bands that are the correct distance apart or a little tight.

The procedure is this:
Set the cylinders loose in the bands.
Position the crossover between the valves and into the valve yoke recesses, but do not fully tighten the screws.
Position the cylinders (try to keep the valves even so the crossover is square with them).
Tighten the bands.
Tighten the yokes onto the valves.

It is a VERY solid system. Everything is in compression.

If you can take a set of doubles already tightened in their bands and are able to then install the crossover on the valves, then the bands hold the cylinders too far apart for that crossover.
OTOH, if the crossover is under too much compression it can be distorted. I have several different crossovers of different makes and models. They pretty much vary in length by a fraction of an inch, so I can pick the crossover of the length which would work best for the bands I'm using at the time.


-DOTD

[capn_tucker]

Good info; thanks duckbill!

[21]

Duckbill
There were two models;
1) the Pig tail
2) solid bar yoke

The pig tail has a 1/2 twist built in to it to allow it's use with cylinders of different sizes and differernt spacing. It was designed and was in popular use during the LP era of 1800 & 2250 PSI

The solid bar yoke was designed and works better with moden HP cylinders

21

[luis]

I don't know about 3000 psi, but concerning the yokes:
The center-to-center spacing of my doubles bands are just the right distance to actually put a fair amount of compression on the "bar yoke" (i.e. Twin crossover). This means that the crossover is under compression. The actual yokes see very little effect from air pressure. I could almost run the doubles with the yokes loose (Haven't tried it, and wouldn't recommend even testing the theory).

-DOTD

I think you should try it loosing it up just a bit, just for testing. Don’t you think that worst that could happen is blow an O-ring.

[duckbill]

As soon as I can get the tanks back from the LDS I'll give it a try. My other tanks have different valves, so the spacing would be different.