Needle valve upgrade - baffled

Patching246 · Post by **Patching246** » Sun Dec 13, 2015 10:10 am

Hey guys. Taken a couple of weeks off to do some work on the house etc. I just took delivery of a 3/8 needle valve to replace the 1/2" gate valve I've using for boka takeoff (from Amazon USA). It seems mighty small, but everything I've read suggests it will be an acceptable size. Am I right?

If so, I need to figure out what kind of coupler I need to fit to my existing setup. I can't find anything that offers the appropriate step down in size AND will work with the male threads. Might need to add additional piping and use compression fittings. Any thoughts?

Post by **bearriver** » Sun Dec 13, 2015 10:19 am

I have a similar needle valve. It should have the needle valve body, a valve stem, 2 retaining nuts, and 2 ferrules. I see everything there except the ferrules.

What I did was soldered the ferrules to the OD of the copper pipe. Then the nuts push the ferrules flush to the body for a seal. That provided me a very strong connection.

Edited fir spellingz

Patching246 · Post by **Patching246** » Sun Dec 13, 2015 10:26 am

Yes, it does have the ferrules. Any way of doing it without further soldering? Of course, I want a booze tight connection, but strength isn't paramount, as I have supports running from the column to the Liebig

Post by **bearriver** » Sun Dec 13, 2015 10:30 am

Here are some pictures of my valve.

Get liquid flux and silver solder online to solder the SS to the copper.

First clean everything and then flux the mating surfaces. Fit your pieces together and hold it with a vice in the horizontal position with the ferrule pointing downward. Now place a single ring of solder on top of the ferrule where it ends so that it is resting on the ledge of the ss. Take your torch and heat this assembly until the solder just melts, and no more.

Clean up the excess solder with a good mill file because even just a tiny bit on the copper will become an obstruction when you engage the threads, thus compromising the seal.

If you bugger it up, don't worry. Replacement ferrules are dirt cheap. Just don't cross thread anything.

Post by **Snackson** » Sun Dec 13, 2015 12:30 pm

If he has 1/2" in there now, he is going to need to reduce from 1/2" pipe to 3/8" tubing as well.

Patching246 · Post by **Patching246** » Sun Dec 13, 2015 1:16 pm

Will be much easier to just find a 1/2" needle valve me thinks.

Post by **still_stirrin** » Sun Dec 13, 2015 7:35 pm

Patching,

Is your needle valve lead-free brass?

Those ferrules create a compression on the tubing, so I don't think you need to solder them. But you would need to reduce the 1/2" OD copper to 3/8" OD to match the valve.

To assemble, put a wrap of teflon tape on the threads and tighten the compression nut and ferrule on the tubing. Make sure you use a wrench on the valve body to keep it from spinning as you tighten the nut. Once the ferrule is compressed on the tubing, the only way to get the ferrule and nut off is to cut it off (I use a hacksaw on the ferrule). But you shouldn't need to remove the nut and ferrule even if you want to break the joint apart (for disassembly).
ss

Patching246 · Post by **Patching246** » Mon Dec 14, 2015 6:37 am

still_stirrin wrote:Patching,

Is your needle valve lead-free brass?

Those ferrules create a compression on the tubing, so I don't think you need to solder them. But you would need to reduce the 1/2" OD copper to 3/8" OD to match the valve.

To assemble, put a wrap of teflon tape on the threads and tighten the compression nut and ferrule on the tubing. Make sure you use a wrench on the valve body to keep it from spinning as you tighten the nut. Once the ferrule is compressed on the tubing, the only way to get the ferrule and nut off is to cut it off (I use a hacksaw on the ferrule). But you shouldn't need to remove the nut and ferrule even if you want to break the joint apart (for disassembly).
ss

Thanks SS - I get how compression fittings work - I just can't find a way to reduce the copper without further soldering. There doesn't seem to be a reducing coupler of that nature. Yes, it is lead free and all others have been hydrogen vinegar soaked until a nice buttery colour.

Post by **cranky** » Mon Dec 14, 2015 6:58 am

When I can't find a coupling that will work I get as close as I can then I flare the tube until it just slides into tho coupling and solder it or solder a cap on then drill a hole the right size to fit the tube and solder it in place.

der wo · Post by **der wo** » Mon Dec 14, 2015 7:11 am

One compression fitting on my needle valve leaked sometimes. I fixed the problem by wrapping some ptfe-tape around the ferrules.

Post by **bearriver** » Mon Dec 14, 2015 8:47 am

Those arent compression fittings like your home depot brass variety. These SS valves are rated for 10000 PSI. All you are going to do is ruin the threads tightening it down like a neanderthal.

The ferrules and body are 314, so obviously there is nothing to compress... Thats why I soldered them, beacuse these type of ferrules are made to be welded to ss pipe. The flare makes the seal like with a copper union.

Post by **bearriver** » Mon Dec 14, 2015 9:05 am

der wo wrote:One compression fitting on my needle valve leaked sometimes. I fixed the problem by wrapping some ptfe-tape around the ferrules.

I did that too, but my valve bears weight so it ended up being really jaynkey. I ran it like that for over a year until this summer when the valve quit responding to overtightening the nuts when it leaked. That blew the threads and ruined the valve.

Soldering resulted in a very strong connection and I couldnt be happier with the result.

der wo · Post by **der wo** » Mon Dec 14, 2015 9:31 am

Mine is 316ss 6000 psi. As still_stirrin describes it, once compressed, there was no way to get the the ss-ferrule off again. But it leaked. And I feared, when I tight the thread every run a bit more to stop the leaking, there will start problems sometime. With the tape I don't have the feeling, that I have to overtight it. I hope so. My valve bears a small product liebig.

Post by **bearriver** » Mon Dec 14, 2015 9:34 am

der wo wrote:As still_stirrin describes it, once compressed, there was no way to get the the ss-ferrule off again. ]

Hrmm, I didnt experience anything like that.

Im off to the research.

Post by **bearriver** » Mon Dec 14, 2015 9:39 am

Here is a pic of the old and new valve, with a highlight on the over turned threads. It was not cross threaded.

Even though I tightened the crud out of it with giant wrenches, there you can see the original ferrules which came right off the pipes. They didn't compress over the copper whatsoever.

I disargee with the idea that these are to be installed like a regular brass compression fitting. Nothing about that makes sense just looking at the material, let alone my experiences.

der wo · Post by **der wo** » Mon Dec 14, 2015 9:50 am

Do you have not two ferrules on each side of the valve? I think, the second one spreads the cone at the wide end, that it gets compressed at the narrow end.
Here a picture from the copper pipe of a waste-part of my old still:

Perhaps you cannot see, but it's really impossible to get the cone off. The narrow side bites into the copper.

Edit: Here is a sketch of the two ferrules:
http://www.gasetechnik24.com/products/d ... stahl.html" onclick="window.open(this.href);return false;" rel="nofollow

Post by **bearriver** » Mon Dec 14, 2015 9:58 am

Looks like we have totally different types of valves.

Both of mine shipped with only one ferrule for each side.

Post by **FreeMountainHermit** » Mon Dec 14, 2015 10:06 am

I have encounter the same ferrule compression as der woo. Prefer the lead free brass valve with the ferrules that accompany them. No sealing issues for me.

Post by **still_stirrin** » Mon Dec 14, 2015 3:15 pm

bearriver & der wo,

Those stainless fittings are called "swage-fit". That's typical of aircraft and oil patch plumbing. The tubing is typically swaged (expanded) inside the ferrule and then you've got a conical compression fit into the socket (female) end of the fitting. If, when you positioned the ferrule on the tubing, you could expand the tubing so it fit snugly inside the ferrule, you wouldn't need to solder. But soldering, as you've done bearriver, is a an acceptable "work-around".

I think I'd be inclined to use a brass (ball) ferrule in place of the conical (tapered) ss ferrule so that it would actually swage onto the tubing when tightened together. Since we're not exposed to high pressure service, the brass ferrule could be "fudged" to work...and you can buy a dozen of them at the big box store for next to nothing.

I do like the stainless needle valves except for the cost. So far, I've resorted to pickled lead-free brass needle valves. And I ain't dead (yet)!
ss

Post by **FreeMountainHermit** » Mon Dec 14, 2015 3:42 pm

still_stirrin wrote:
Those stainless fittings are called "swage-fit". That's typical of aircraft and oil patch plumbing. The tubing is typically swaged (expanded) inside the ferrule

Never encountered the above in my years of constructing high pressure vessels in the industrial pharmaceutical refrigeration industry.

Typical method from my exp.

Post by **bearriver** » Mon Dec 14, 2015 3:43 pm

Thanks for the information SS and FMH! I will not be recommending this type of needle valve anymore.

Post by **FreeMountainHermit** » Mon Dec 14, 2015 4:11 pm

Hands on exp. is tough to beat. Never saw tubing over a mandrel as SS stated.

Cheers.

drmiller100 · Post by **drmiller100** » Mon Dec 14, 2015 4:19 pm

you'd think needle valves would be such a simple thing.

But they are a ROYAL PITA. hard to find a NEEDLE valve which you use wtih more than 1/16 turns to try to control reflux.

any good sources? Looking for reflux on 5000 watts or so.

Post by **shadylane** » Mon Dec 14, 2015 4:33 pm

Valves used on cutting torches and welders work good.
Their made for fine flow control and readily available.

Post by **Snackson** » Mon Dec 14, 2015 7:55 pm

drmiller100 wrote:you'd think needle valves would be such a simple thing.

But they are a ROYAL PITA. hard to find a NEEDLE valve which you use wtih more than 1/16 turns to try to control reflux.

any good sources? Looking for reflux on 5000 watts or so.

http://www.amazon.com/gp/product/B00EZ3 ... B0OJ7553H5" onclick="window.open(this.href);return false;" rel="nofollow

I've seen these used to control cooling water for reflux, that way you can dial it in and it will offer repeatability.

Monkeyman88 · Post by **Monkeyman88** » Mon Dec 14, 2015 8:55 pm

drmiller100 wrote:you'd think needle valves would be such a simple thing.

But they are a ROYAL PITA. hard to find a NEEDLE valve which you use wtih more than 1/16 turns to try to control reflux.

any good sources? Looking for reflux on 5000 watts or so.

SwageLok needle valves. Will cost you your first born but very fine adjustment.

https://www.swagelok.com/en" onclick="window.open(this.href);return false;" rel="nofollow

YHB · Post by **YHB** » Tue Dec 15, 2015 3:45 am

It always seems strange to me that people spend lots of time making a Bok, then go and buy a very expensive needle valve.

You do not need a pressure rated valve for the discharge of a Bok, the pressure is as near zero as you can get.

Here is a DIY needle valve, that uses a stainless steel bicycle spoke as the needle. I have made a few for people and they take less than in a couple of hours. This particular one is over 4 years old and shows no sign of wear and tear.

They are very controllable down to 1 drip every 20 seconds. Cost - approximately Two UK Pounds.

: Needle Valve 3.JPG (8.02 KiB) Viewed 3421 times

der wo · Post by **der wo** » Mon Dec 21, 2015 8:40 am

Yes, YHB, I like your needle valve design, especially the Mark 2. It's perfect for a boka I think. But I did not build it, because I had incredible luck at ebay.

But I have two questions:

-Did you ever think about to build it reverse LM? It would be easy with your design: The downer Tee turned to the right would become product output and under the needle hole it would need a 90° angle to the column for reflux return? It had the advantage, that the smearing by the pool would affect more the reflux, less the product. And of course the control would act different.

-I think, you can strip with zero reflux. But with how much power or output rate? Did you consider once about a larger hole and thicker needle because of that? For example a stainless knitting needle (of course you had to cut or mount a thread at the upper end)?

YHB · Post by **YHB** » Mon Dec 21, 2015 11:13 am

Yes I did consider RLM but decided against it, with LM and a reflux ration of 90% the needle valve has to control 10% of the reflux, with RLM the needle valve has to control 90% of the Reflux. Yes I suppose I could have used a bigger needle but I do not think it would be that straightforward, the bigger the needle the less if will flex, the thin bendable spoke will bend as it closes and find its way into the hole, if the bigger / stiffer needle was slightly out of alignment I think it would just jam.

For stripping I initially just removed the valve, screwed a cap on the bottom connector and put a downspout on the top one.

I did develop my column and made a LM/VM combo with a proportional splitting head which worked a treat, I also has the added advantage that if you direct 100% of the vapour to the VM take off you instantly have a pot still / stripper.

der wo · Post by **der wo** » Mon Dec 21, 2015 11:32 am

Many good info, thank you.

YHB wrote:with LM and a reflux ration of 90% the needle valve has to control 10% of the reflux, with RLM the needle valve has to control 90% of the Reflux.

Ok. So for controlling the RLM you would need a finer thread? And for setting 100% reflux to stabilize azeo a wider hole/thicker needle?
A stiffer needle would find the way easy, if it's not fixed too strong at the thread . Because it doesn't have to be sealed at the top, perhaps it would be easy, to use a thicker needle.

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