Well, I have frost....

[SexyMF]

Hope it is ok with you SmF that is post in here again.

I muse that you hold such a beef so many months later. That speaks a lot more about you than me.

But your prayers are answered and RussC is locked and loaded!

[Darkenreaper57]

Nice work with the setup.

[RussC]

Well,
I havent worked on this in nearly half a decade. But the Bulldozer release has sparked my need for cooler temps.

So, Im going to use a vapor line heat exchanger for the system, as it may give some better temps. Got all the stuff back out. Im going to make a simple dirty resivior again just to get it up and running in the next month....



New suction line heat exchanger


Whole bench ready for work.



Im a sucker for cheap condensing units off Ebay...got both of these for under $100..



More later in the week..

RussC

[RussC]

Makin progress....
fabed up some pcs for heat exchanger...


Low side gauge mountings...


And return back to the compressor..


Goin to use that .5gal cooler as a quick and dirty resivior. The TVX will hook to in in some fashion, as well as all the tubing, low side return and pump power.

RussC

[RussC]

Well,
All the non-evap piping is done. This is the competed high side and low side piping. I should get this all brazed up pretty quick.



Next is how to get the TXV into the cooler....



I essentially have everthing I need, gotta get the coil wound for the evap and mounted to the cooler. Im going 3/8" bulkhead tube fittings on the top of the evap, I believe....but Ill know more when I see how the pump fits in there.

RussC

[n00b 0f l337]

Might want to look over your plumbing again before you braze, the SLHX should be after the condenser, after the filter drier and after all high side access fittings.

[RussC]

Too late, already brazed it all in. Why?

Might want to look over your plumbing again before you braze, the SLHX should be after the condenser, after the filter drier and after all high side access fittings.

Anyway, more pics of it all put together and brazed....










I need a differnt pump than I had. Needs to be smaller to fit in the cooler. Ordered that today. Havent decided what size tubing for the evap yet, more later.

RussC

[n00b 0f l337]

Because as is, you are adding huge amounts of heat to the compressor, then; you are warming up the refrigerant in the condenser if it actually gets cold enough.
You have to move that.

[RussC]

Because as is, you are adding huge amounts of heat to the compressor,

Umm, Im not getting where the heat is comming from?

then; you are warming up the refrigerant in the condenser if it actually gets cold enough.
You have to move that.

Ok, this I think i understand. This would only be under no load conditions. Would this really be an issue with a TVX though? In theory the TVX shouldnt let that much unused refrigerant into the suction line, or am I off in my thinking?

Thanks,
RussC

[n00b 0f l337]

From the hot discharge line of the compressor. Your going to add that heat right back into it.
As for the TXV, it can't be setup like that, you want to run it's sensing bulb to BEFORE the condenser.

Replumb it.

[RussC]

Ok, I understand the issue, the heat is xfered in both directions, but insn't the major thrust of this suction side heater to keep un-used refrigerant from entering the compressor?

Im going to put the TVX in the normal spot, the last device in the high side just before the evap. My TVX also has the pressure sensing port, so it needs a port to that input after the bulb in the suction line. I guess I need to make a diagram that helps ferret this out.

Thanks,
RussC

From the hot discharge line of the compressor. Your going to add that heat right back into it.
As for the TXV, it can't be setup like that, you want to run it's sensing bulb to BEFORE the condenser.

Replumb it.

[wdrzal]

In post 82 (2nd pic from last) you have a low side gauge on the high side & a high side gauge on the low side. They need switched.

[n00b 0f l337]

Good spot Walt, he had it right before though.

[RussC]

Ya, there swapped, was just in for mock up...thanks for the catch...

Did some work today. Im going to put a sight glass in, but it hasn't come in yet, but Im moving forward anyway. Got the new piping in for the SLHX...





Started the evap section, will try to wind up the evap in the next day or so..



RussC

[wdrzal]

Some of the conectors you are using look like they are the type that use compression rings. If they are they will probably leak, and could blow apart if not tight enough,but over tighten and they will leak for sure. I prefer swage joints or flare fititngs,double flaring if you use flares.

[RussC]

I knew someong would eventually say somthing about the comppression fittings

Um, Im using Parker double sleave(ferrule and top ring) fittings. 2 mechanical engineers and myself looked at all the data, theres nowhere we could find that says a "good" compression double ferrule seal tightened properly is any less of a seal than a flare. Its a metal to metal seal that holds as as well as any metal to metal seal. In fact, looking at it seal characteristics, its a larger metal seal area than a flare or VCR fittings we use. Its pressure holding is as good as the burst pressure of the pipe. We use them on vacum and pressure seals on our plasma etchers that pump down to 10e-9 Torr and pressurize to 300psi. They also pass our helium leak checking with an RGA all the way down to 10e-10 leak rate.

The cheapo ones that you buy at Orchard supply arent nearly as good as the Parker or Swagelok units. I wouldn't use those.

Now with all that said, well see if they leak. I have absolutely no worries of them blowing apart. Again, all the data from Parker and Swagelok say they seal as well as the burst pressure of the piping used.

RussC

Some of the conectors you are using look like they are the type that use compression rings. If they are they will probably leak, and could blow apart if not tight enough,but over tighten and they will leak for sure. I prefer swage joints or flare fititngs,double flaring if you use flares.

[wdrzal]

I've seen the double ring compression fittings from parker,but only in stainless steel for stainless steel tube. Never seen them in brass for copper tube. Those are a little pricey and I see other brazed swage joints so I'm not sure why you even used them?

Most people just buy the standard compresion fittings from home depot or any hardware store.

Let us know how they perform,both during the intial leak test and if they hold up over time. Vibration is a big concern for me.

[n00b 0f l337]

I just don't see why you didn't braze them up.

[RussC]

I've seen the double ring compression fittings from parker,but only in stainless steel for stainless steel tube. Never seen them in brass for copper tube. Those are a little pricey and I see other brazed swage joints so I'm not sure why you even used them?

Most people just buy the standard compresion fittings from home depot or any hardware store.

Let us know how they perform,both during the intial leak test and if they hold up over time. Vibration is a big concern for me.

There vibration rating is the same as flare. If you have concerns with that, then just like flares, use some Locktight. Also, compression tube fittings are used in automotive applications, these chiller aren't nearly as bad as a car for vibration.

I just don't see why you didn't braze them up.

Well, I have, ~6 times on this rig alone. Id like to have the system more modular, since I want to re-use this stuff for other builds, especially the compressor. I may want to pop this 1/5hp unit out for that 1/2hp on the bench. These conn's would make it alot easier.

Anyway, made more progress...Ill have more pics tomorrow.

RussC

[RussC]

Well, its all together....Got it all cinched up, tightened, evap made...






An then like always, disaster strikes...

As I was tightening the flare, it twisted the evap inlet and kinked it but good..Mother FU%^er, Son of a Bit^&. See why I like the modularity of the fittings. Now I dont' have to un-braze and then re-braze on system. I can pull it off to do it. And its really too bad, its holding great vacum

More later...

RussC

[n00b 0f l337]

Looks like an easy fix, make sure to put the TXV bulb after the SLHX.

[RussC]

Looks like an easy fix, make sure to put the TXV bulb after the SLHX.

Ok, not sure why, but sure.

But, on too next disaster....off all the things to leak, the NPT fitting for the low side gauge will not seal, now I stripped it trying to tighten it to seal. Oh well, I believe Ive ruined the threads on the gauge.

So my question is, do you use some sort of sealer so you only get these tight enough to get in the right position ie you can see the gauge face, and the sealer does the rest? If so, suggestions on a thread sealer?

I see theres a thread sealer on my manifold, I would guess thats what they do.

RussC

[wdrzal]

You can use teflon tape thread sealer ,but be carful to start it back 2 treads so it doest get cut off and sucked into system. Also you need to wind it closkwise if your looking at the hole in the bottom of the gage. About 2 or 3 turns. Or pipe dope for gases.

You should tighten the gauge into the fitting first,then face it forwards and braze. No problem.

I avoid threaded connections when possible.........buy gauges with flare fittings.

[RussC]

You can use teflon tape thread sealer ,but be carful to start it back 2 treads so it doest get cut off and sucked into system. Also you need to wind it closkwise if your looking at the hole in the bottom of the gage. About 2 or 3 turns. Or pipe dope for gases.

You should tighten the gauge into the fitting first,then face it forwards and braze. No problem.

I avoid threaded connections when possible.........buy gauges with flare fittings.

Ok, but the whole idea is to have a removable gauge in case it fails and needs to be replaced. Again, they have some sealant on my manifold, I guess its one of the LockTight sealants Im guessing.

In looking at this further, since the the fitting and the gauge threads are hosed, I put some LockTight sealant on it and letting it setup overnight. If that doesn't hold, I'll redo, clean it all up and JB Weld it in. The that doesn't work then I'll un-braze the NPT fitting off and start from scratch with a new fitting and gauge.

RussC

[wdrzal]

Ok, but the whole idea is to have a removable gauge in case it fails and needs to be replaced.

RussC

Right........you just loosen the flare nut,no sealer needed.....plus you can lock it down in any direction........plus you don't have to braze close to the gauge. Especially if you have a plastic cased one.