Valve Banks

[RobotWolf]

Hello all,

Since I'm very new to the hobby, I wanted to ask a few general questions about the valve banks; the original ones supplied by CEI.

The fellow I've done most of my hobby purchasing from told me that they were 4-way valves. The four ports being: the two lines going to the cylinders, the supply and the exhaust.

Purpose: I'd like to be able to build a modern valve bank and obviously want to make the right decisions.

So the question is: Among you hobbyists, is there a preferred and possibly more modern equivalent to the original mac valves supplied by CEI?

Thanks in advance for any advice and/or suggestions!

[menutia]

Do what CEC does... use new MAC valves!

[RobotWolf]

Do what CEC does... use new MAC valves!

Sounds like great advice, thanks.

Am I right in thinking I need 4-way valves? Is there, by any chance, a part number someone might have?

Again, Thanks !

[captslappy]

Shawn, there are also some other brands out there. I plan to do some experimenting once I have time and get my show running again. I'll let you know what my findings are after some research. Stay tuned!

[pizzacam]

Yeah I mean the original MAC brand valves have alot of issues and were HEAVILY used in Showbiz Pizza's/CEC's so if you were to buy NEW MAC brand valves... you probably wouldn't see any problems for years(depending on how often you use them of course).

[showbiztech]

The original MAC valves used were the 913A series. They have been discontinued. MAC uses the 913B series as a replacement. It stacks inline with the 913A series, so you can can mix them together on the same valve bank. The full part number for the replacement 913B valve currently used by CEC is 913B-PP-611BA. You can also use 913B-PM-611BA. The "PP" stands for "ported pilot," which refers to the pilot valve with an exhaust port. These are all the airlines that come off the front of each valve and go to small manifolds that go to the large aluminum rectangular exhaust manifold on each valve bank. The "PM" does not have a port on the front of the pilot, and instead the exhaust is routed back through the valve and out the exhaust lines on the end caps. It makes the air exchange slightly louder, but I don't think it's a real big deal.

If you go to your local MAC distributor, expect to pay about $45-$50 for one valve. Maybe it's a little expensive, but a cheaper valve will most likely result in cheaper quality. As pizzacam pointed out, these valves have a 30 year track record under heavy use. Maybe there's another valve out there that has all the same specs as these, can be stacked together, and is cheaper, but I highly doubt it.

[captslappy]

I hope to test the Humphrey M401-37 valves in the next few months and see how they compare. I'll give a full report but I know these valves are also obsolete (although more recent then the mac valves). We'll see what happens.

[puppetmaster29]

Do what CEC does... use new MAC valves!

LOL I wonder where that picture came from?! I remember that picture as if I was really there.

[PaulKTF]

LOL I wonder where that picture came from?! I remember that picture as if I was really there.

Okay; I plead ignorance- is there something funny about that picture? IF so, what? Fill me in. :)

[captslappy]

LOL I wonder where that picture came from?! I remember that picture as if I was really there.

Nah, it is a clever Photoshop job. You only think you were there.

[DerrickTheHedgehog]

Do what CEC does... use new MAC valves!

Well, I think I know why Colerain's has been in good shape for years. But If they didn't, I hope they use these.

[showbiztech]

I checked the datasheet on that Humphrey valve. The flow coefficient (Cv) is only .05. The flow coefficient on a MAC 913B is 1.4. The way I understand it, that means that the MAC valve would fill the same cylinder with the same airline going from the valve to the cylinder 28 times faster than the Humphrey (1.4/.05). I think that would result in delayed movement and possibly slower movement.

That explains why on some shows Wink doesn't work all the time. Since the airlines have such a long travel from under the stage to above the ceiling, the air doesn't always make it to the cylinder. You would either need a valve with a higher flow coefficient, a shorter run on the airlines, or have the valve coil energized for a longer period of time.

Maybe puppetmaster could go back and look at various shows throughout the years and see if there's any difference in the length of time the Wink signals are programmed for???

[captslappy]

Hmmm, that's interesting to know. I wonder if that could be compensated by adjusting the flow controls?

[PaulKTF]

It's nice to have an explanation as to why the wink is out or slow on so many shows

[captslappy]

The wink connects to the prop valve bank where the spider used to go so that shouldn't make any difference. That was the only real change in the whole thing was the wink replaced the spider mech and it has to have a substantially smaller cylinder in it. The same valve is controlling that mech so there should not be any real difference there. If there are problems with it, it's either a bad design on that prop or a cylinder problem.

[showbiztech]

Or, there's a problem with the programming. For example, if I took two different show tapes and Wink worked on one but not the other, then the only explanation is that there's a difference in the programming. Same show, same valve, same airline, same cylinder, same distance from the the valve to the cylinder, etc. I put in one show and it works, then I put in another show and it doesn't.

As far as the Humphrey valve goes, I think the only way to possibly compensate would be to increase the air pressure or shorten the airlines. I believe air pressure is part of the formula for calculating flow coefficient. Adjusting the flow control will not affect how fast the air travels from the valve to the cylinder. Although, you could configure it that way and see what happens. Keep in mind, I'm no expert on air flow and such. I'm just trying to bounce around some logical ideas based on my knowledge of the 3-stage.

[captslappy]

You raised an interesting point though. I am going to be rebuilding my Mitzi and may use the Humphrey vales on her. I'll do some experimentation and get back to you. It will be the next several months before I get to it and get her all done. As for the wink, from all the variables you described, I'd have to agree. They didn't lay the signal down long enough for it to have time to react from the sounds of it.