I'm building a heat exchanger. It's 12" sections of 1/4" soft copper pipe half full of R134a. Only problem is filling/sealing them. I need a bunch, so a fill adapter for each one is outa the question. Schrader valves from old inner tubes work, but they're a lot of hassle. I've tried crimping/folding/soldering. Can never get it quite sealed so the solder will stick.
What's the trick to mashing the pipe so it seals well enough to get the solder on?
Thanks, mike
After you pour the R134a in, quickly apply one of these to the end of the tube
I think what you want is a "pinch off tool".
If this is for a DIY heat pipe and will be used above freezing, just use distilled water as the working fluid. You can easily control the temperature at just above the boiling point to purge the air out but not have so much pressure that it keeps the solder from wicking in.
Thanks, Typical ads say, "locking clamp...free both hands for other tasks." Suggests that I need to leave it clamped till the solder is done. Duh!! I'll try that.
They changed designs, since I last saw one of these. This is what I found.
if you fill this tubes and seal the then there is no heat exchanger any more! it seems to me that your trying to lay the egg without chicken! you are not making heat exchanger you are playing with your self! In my 55 years in refrigeration I done some stupid things I seen some stupid things I hear of stupid things but man you deserve certificate on stupidity of century.
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Heat pipe, look it up. A sealed tube lined with a wicking material that is saturated with the refrigerant of interest. If heat is applied anywhere along its length the refrigerant evaporates at that spot and recondenses everywhere else where it is cooler. They are used extensively in computers these days to help transport the heat away from the high wattage chipsets, CPUs, and GPUs.
If the OP omitted the wick then his will only work upright by gravity return with the heat applied at the bottom.
ZACTLY!
Turns out that the tire shop will give you all the used tire valve stems you want. Solves the sealing problem. Stick an air chuck on a R-134a can and I can fill 'em with ease.
Heat pipes work great. Kinda cool to use a stethoscope to listen to them boiling away as the heat moves.
Big problem getting heat from air into them with LOW temperature difference. Looking for any design info on optimum fin shape for heat transfer from air to pipe.
Thank you very much for your heartfelt encouragement. Reading it was the most fun I've had all day. I think the kids call it ROTFLMAO. As for your 55 years...sometimes COMPETENCE is more important than LONGEVITY. Willingness to learn new things is also helpful. Please reconsider who should get the certificate.
Waddya mean ? Waddya mean ?
The problem with tire valves is that they're made for air. The valve cores do not use the same sealing materials as those for refrigerant. If you use an automotive valve stem, get valve cores made for refrigerant use. If you're going to make a bunch of heat pipes, get a process tube adapter to use along with a pinch off tool. To get a consistent amount of refrigerant into your tubes, you'll need a way to measure the amount of charge by using a scale or charging cylinder. I don't know how much money you want to spend making your on heat pipes but you may consider purchasing them from a manufacturer who has already spent tons of money on research and development.
So you are making heat sink and not heat exchanger, and if you going to do that you better make sure that heat is limited to respond to refrigerants pressure. Also if you want fill the tube with refrigerant you must cool the tube to a temperature matching the refrigerant "0" pressure. good luck
They are used extensively in computers
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Pick pick pick.
Niggling little details all the time with you ......
Yep, but they work just fine for prototyping.
If you're going to make a bunch of
This is a hobby. Expensive tools are out of the question. Spending $7 on a pipe swaging tool made me cry. The heat pipe thing is a fun diversion trying to save some weight. I expect by the time I'm done, I'll be going back to a parallel-plate cross-flow heat exchanger.
To get a consistent amount of refrigerant into your
Stick ice cubes on the bottom half of the pipe and fill from top. Liquid condenses up to the level of the ice.
Verify with stethoscope listening to the pipe. Small heat source moved up/down the pipe. You can hear it boil when you reach the liquid level.
I don't know how much money you
ZERO!
but you may consider
No fun in that. Might as well go buy an HRV and pay to have it installed. It's more about the building and learning than the end result...and saving most of the thousand bucks.
Thanks, mike
I don't know about him, but I'M MAKING A HEAT EXCHANGER. You just like to argue. Grumpy is an excellent selection for a "handle". Rave on...I'm enjoying the show.
Explain. I've been filling them at room temperature with no problem.
Thank you, but knowledge and skill work better for me. Got any of that to impart?
Wait until I retire then real problem will start I will be busting every body's bolts
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I stuck myself in the eye with a fork once - made me cry, too !
Really ? R134a condenses at 32 F and 0 PSIG ? Wow. I never knew that.
Can I come over and watch ? Because I'd really like to see you do that. I'd really like to see you 'pour' your 134a ( I think you mentioned it ? ), out of the jug, which will have ~ 80 PSI of pressure in it at room temperature, as a liquid, into a open container at 32 F, and have it sit there as a liquid. I'd really like to see that. Seeing as that's only ~ 42 degrees above it's boiling point at atmospheric pressure.
Yessirre, Bob, that would be a good one to watch . You see, I would expect it to BLAST out ( under 80 PSI of pressure at room temp in the can ), and ( assuming you're pulling liquid ), instantly boil off to a gas as it hit room pressure of 0 PSIG ( 14.7 PSIA ). Silly me. That's what I would expect.
But that's just me, it may work different for you.
Or you could stick your tongue on the pipe and see if it sticks. That would make about as much sense as the rest of your crap.
He asked how much you want to spend, not how much you know !
Hope you have great insurance !
You're confusing your failure to read/understand with my creativity. More thinking and less typing is in order.
Right on both counts. I ask questions when I don't know something. So far, there's been ONE response that actually helped somewhat. The rest have been restating the obvious... I need constructive, creative help, not criticism.
You should learn to read instead of making stuff up to show your superiority. What I actually said was: "Stick an air chuck on a R-134a can and I can fill 'em with ease. " No mention of atmospheric pressure at all. Note the title says, "UNDER PRESSURE".
It is hard to not be pissed off by all the mudslinging when it's at me. But I'll get over it and move on.
Snicker all you want...I've got heat pipes that work even without your "help".
Well, Mike, I find a lot of those expensive tools at pawn shops. I bought a swaging tool kit for copper tubing some years ago at the supply house for $100 and later picked up an identical kit at a pawn shop for $50. I got it for a friend I work with because he'd been admiring my kit. I go around to all of the shops I can find because of the great stuff I can pick up.
TDD
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