# [Wet Thumb Forum]-Add-on equipment to Clippard needle valve



## BobAlston (Jan 23, 2004)

If you use a clippard needle valve, as I do, you probably know that the adjustment is somewhat tricky, in that there is little needle turn to make the adjustment. I have my regulator set at 10 lbs of pressure. It would be great to find a way to make the needle "more sensitive", e.g. to be able to use more of its adjustment capabilities.

Toward that end, I wrote Clippard and they suggested trying an "air choke" that they offer. Item MAC-xxx. Cost is $4.55. Four models; smallest has a hole diameter of .006 (inches ?).

Anyone try this or similar?

I also found a company that sells similar devices with the smallest being .0039 diameter
http://www.okcc.com/pdf/NPT.pdf
their literature states an equivalent Cv of .00035

Bob


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## BobAlston (Jan 23, 2004)

If you use a clippard needle valve, as I do, you probably know that the adjustment is somewhat tricky, in that there is little needle turn to make the adjustment. I have my regulator set at 10 lbs of pressure. It would be great to find a way to make the needle "more sensitive", e.g. to be able to use more of its adjustment capabilities.

Toward that end, I wrote Clippard and they suggested trying an "air choke" that they offer. Item MAC-xxx. Cost is $4.55. Four models; smallest has a hole diameter of .006 (inches ?).

Anyone try this or similar?

I also found a company that sells similar devices with the smallest being .0039 diameter
http://www.okcc.com/pdf/NPT.pdf
their literature states an equivalent Cv of .00035

Bob


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## gsmollin (Feb 3, 2003)

That's about 100X more than the Cv that you really need, which is about .000002. None of that equipment is designed for what we use it for, including the needle valve. That is why you have trouble adjusting it.

There are two methods that may help here. One is to get a better needle valve. The other is to cascade needle valves. Then you could set the upstream valve to a couple bubbles/sec. then adjust the downstream valve to a low flow rate. I did both. I have two Swagelok S valves connected in cascade. Fine adjustments are very easy.


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## BobAlston (Jan 23, 2004)

Gsmolin -

Thanks. Interesting. I asked Clippard about putting the valves in series and he didn't think it would help much. I just may need to try it.

Bob


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## BobAlston (Jan 23, 2004)

gsmollin -

another question, if you would be so kind.

Two Swagelok S-series valves. Wow. Can I assume that you have a lot of valve movement to adjust the bubble rate? I would assume so.

Did you ever run with just a single S-series valve? How satisfactory did you find that?

Ever looked at the Parker HR series? The H0 valve has a max Cv of .0004, finer than the S-series but likely no match for two s-series in tandem.

I have been researching for possibly upgrading from the Clippard. It works but the adjustment range is pretty narrow. But, maybe a second Clippard, for +$10, would make more sense. I just wish I knew more about gas flows, pressures, etc to be able to think thru it better.

Thanks for the info and advice.

Bob


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## gsmollin (Feb 3, 2003)

I have done some research in this area, and yes, I think I can answer your questions.

I have a lot of valve valve movement to make adjustments with the S series valves. My use of two valves is not driven by that, however. It's driven by redundancy. I use a pressure setting of 37 psi. That number is chosen so that if the regulator pressure suddenly jumps (e.g. fails)to the relief valve setting of 60 psi, the CO2 going to the fish only increases by 1.5. The two valves in series also give me redundancy of operation, so if one fails open, the CO2 increases by less than 1.9. There are other redundancy configurations in the CO2 setup, so that no single-point failure can gas my fish. I have posted this whole treatise in the past, to the usual no-response.

Since this is a redundancy thing, I setup the system with one valve before cranking down the other. I find that I get an incremental sensitivity of about 1 bubble/sec change per revolution of the valve handle. For instance, I adjusted the flow rate recently from 0.6 b/s to 1.1 b/s with a 1/2 revolution turn to both valves.

Before I bought the S series, I tried to buy the Parker HR. It looks great, doesn't it? Unfortunately, buying one is an uphill battle. Parker has actually only made three types of these valves, and if you don't order that exact configuration, you get a tooling quote along with a minimum buy and a 12 week delivery. So I went back through the distributor to find out which ones were available, and got a quote of $104 each, if memory serves. This all took about a month of back and forth, and so I gave up and ordered the Swagelok S's along with some fittings.

For the money, its hard to beat the Clippard. I used one for about 3 years, and it was reliable. However, I got impatient with the lack of adjustability. At one point, I had designed a system with three of them in tandem. The problem with that on the MNV-4 valve, is that its a right-angle valve, so is a bitch to configure in tandem.

I also dreamed up all kinds of other choke systems, including some labyrinth chokes, and skeins, but I wasn't sure about the reliabilty of this type of DIY, and I wasn't motivated enough to do the qualification testing on such a project.

So. ultimately, I just bought the valves retail, and paid the going rate. That brings the expenditure to somewhere near an Eheim Pro II cannister, but the performance is definitely there as well. Most aquarists would say I went overboard, but then those same guys will buy a pH controller, and end up spending more than I did. So I say they went overboard too.

You can choose your own course. Good luck.


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## BobAlston (Jan 23, 2004)

gsmollin -

thanks so much for the great info.

One last question (well maybe not the VERY last):

How much improvement in the adjustability of the gas flow did you find in the second valve over just the first valve (if you set it up with only one at first)? What I am trying to figure out is what kind of adjustment improvement I might expect from a 2nd Clippard??

Interesting info on the Parker valves and availability. Thanks.

Bob


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## gsmollin (Feb 3, 2003)

With two valves the adjustment is twice as easy as with one. Now if one valve is absolutely terrible, then two will just suck, and that's a definite improvement.









I think there has to be a strategy with using two Clippards. If I were doing it, then I would use them as a coarse and fine adjustment. Say you want 1.0 bubble/sec. I remember it was really tough to get the adjustment that close. However, if you could get between a range, say 1.2 to 1.5 bubbles/sec, then the coarse adjustment could be locked there, and the second valve could be used to lower it to the exact 1.0 bubble rate. Then you could get a 3X to 5X improvement in the control, using the "fine" adjust valve. It isn't going to ever be easy, unless you string together 5 or 10 valves, and of course that doesn't appeal to anyone, but I think you could make it tractable.

Part of the problem I saw, is that you're already up to at least $21 in needle valves, plus the pain of connecting them together, and its only a moderate improvement over the single valve. Honestly, I don't know if you'll be satisfied after all the work. I have a junk drawer of other valves I tried before the the S series, all of which I hated. I would rate Clippard MNV-4 as second best, albeit a distant second.


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## Jim Miller (Feb 3, 2003)

Has anyone tried one of the Fabco valves? At least on paper they appear to be well designed for our purposes with a finer adjustment than the Clippards and machined vs cast construction. Price is around $20 IIRC. Unfortunately I've lost my catalog in all the packing we're doing and their catalog isn't on line rather on CD which you can order.

jtm

Tank specs in profile

[This message was edited by Jim Miller on Tue April 08 2003 at 03:53 PM.]


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## BobAlston (Jan 23, 2004)

JIm -

do you have the specs on the Fabco valves? I haven't seen any and I couldn't find them on their web site.

I am just curious.

bob


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## STAT 007 (Mar 8, 2003)

"Cascade" the needle valves? Is this just a fancy way to say "connect them in series"?

Sincerely,
STAT 007
Fightin' Texas Aggie Class of 2004

37 gallon AGA Black Seal, Emperor 400, Ebo Jager 200 W, 100% Flourite Substrate, 2x55 Watt AH Supply PC Lighting (5300K & 6400K) @ ~3.4 WPG, High-Pressure CO2.


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## Rex Grigg (Jan 22, 2004)

Yes.

Moderator










American by birth, Marine by the grace of God! This post spell checked with IESpell available at http://www.iespell.com

See my Profile for tank details.


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## STAT 007 (Mar 8, 2003)

LOL. Thanks, Rex. I sometimes get confused when people add extra words to fancy things up.









Sincerely,
STAT 007
Fightin' Texas Aggie Class of 2004

37 gallon AGA Black Seal, Emperor 400, Ebo Jager 200 W, 100% Flourite Substrate, 2x55 Watt AH Supply PC Lighting (5300K & 6400K) @ ~3.4 WPG, High-Pressure CO2.


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