-
Originally Posted by
Sailfast
The problem with solid co2 is heat transfer.. hence putting it in the actone.
Actually liquid nitrogen is entirely safe but unnecessarily cold.
Dry ice in the acetone bath should be sufficiently cold. Use the acetone because it will not freeze at -150.
Make the outer pipe about 2.5 feet long, inner about 2.3 and put half of the assembly in the bath, works great.
Sent from my SM-N915T using Tapatalk
Well if thats the case and you need to have liquid
straight N2 sounds safer lol
How about roughing the vacuum without the pump?
https://www.vaccon.com/standard-prod...-categories-36
-
-
-
Originally Posted by
itsiceman
Probably cheaper as well. Liquid N2 really isn't a problem as long as it is handled properly..
Sent from my SM-N915T using Tapatalk
-
Originally Posted by
itsiceman
Thats interesting, wonder how well it works.
Originally Posted by
CHILLERSVCMAN
My first question is what is the tonnage of the machine ? Depending on tonnage and logistics , replacement may be more cost affective then attempting to dry the system . Next question : What caused tube failure ? What was result of eddy current test ? Eddy current test could be the deciding decision maker . If other tubes are marginal ; don 't waste time or effort . Park a rental for now and let customer evaluate and make decision with options - not under stress . ( I am not a salesman ; I have given customers the rental option and have them trust me with other decisions . ) Rentals can be set any place - air or water cooled ; with or without pumps , generators , and fuel cells .
Tried to talk them out of fixing it for about 8 months, they decided on a new evap barrel.
Originally Posted by
pecmsg
That looks cool but I'm wondering if its big enough, those 1/4 inch barbed connectors look kind of cheesy for some 1/2 inch hoses lol but that design looks like it would work.
-
If I bought a R404 low temp condensing unit and bolted it to a 4 wheel hand truck I would just need to design and build some kind of evap out of a 30 or 50 lb recovery tank, I could put 1/2 inch hose fittings on it, insulate it and put a sight glass and drain in the bottom and it would all be self contained.
-
Originally Posted by
BBeerme
I would be building something similar to a still. Can't remember all of the proper terminology, but can look it up if you are interested.
Here's the idea . . . You use one compressor. And in that circuit [old school] was r-12, 13, and if you want even colder temps, r-14 as well.
The idea is that the air cooled condenser condenses the r-12, then that is fed back through a cap tube to further cool the discharge gas condensing the r-13. And if even colder temps are required, that condensed r-13 is fed back to what is left of the discharge gas to condense the r-14.
In reality, there were up to five different refrigerants used, depending on how cold you want to go. Today you would use different refrigerants than I mentioned, but the concept is exactly the same.
You're thinking of an Auto-Cascade System. Here's an article from the lost archives of Sporlan which explains it rather well:
http://icemeister.net/backroom/wp-co...rigeration.pdf
-
Yeah, I used to work on those a lot. Even built a few myself from scratch.
Nice thing is you don't need to be concerned with running out of ice, dry ice, liquid nitrogen, etc.
Originally Posted by
icemeister
-
My preferred method: a cold trap similar to joeysmith with a small refrigeration pack cooling a homemade evap coil dipped in glycol
Another method when I worked for another company: a large industrial vac pump with a large oil filter to cope with the moisture
-
Please keep us updated on your progress . I would like to know the eventual outcome and methods used .
-
-
Originally Posted by
Dilp172
that looks perfect
Keep it simple to keep it cool!
-
Originally Posted by
Dilp172
Thats the design I decided to go with but mine is going to be larger and have 1/2 inch hose fittings on it, the dry ice seems like a pretty good way to go, when mine is finished I'll post up some pics.
-
Post Likes - 1 Likes, 0 Dislikes
-
I've wanted to try an air dryer. Like the ones used for a pnematic system.
-
I've used the style chillrdude posted a pic of. Worked well for me when 2 1200 ton centrifugals sunk. They were clean full of water. One didn't make it through transition due to impellers in water, the other made a birds nest of the windings immediately. Yeah, they didn't know and started them. I think the customer tried acid cleaning their own tubes and let it sit just a little too long... they were like Swiss cheese.
Anyway, we also added rubbing alcohol to the dry ice to get more surface area in the can. Couldn't believe the ice we got out of it! Ours is a little larger with 1/2" ID hose barbs.
Last edited by BennyD; 03-04-2017 at 10:57 AM.
Reason: typo
-
Would it be possible to build a reasonable cold trap cooled by ice and calcium chloride?
You should be able to get to 50 below zero with that.
-
Thats what were talking about!
-
I thought everyone was talking about dry ice, liquid nitrogen, or a separate refrigeration unit.
I missed where people were talking about regular ice.
-
Cold traps used on centrifugals need to have at least 3/4' pipe inlet and outlets. The larger the better. We had 2" on ours that we built, and oh yes, build them out of aluminum as they tend to be very heavy, When pulling vacuum, you only have maximum amount of pressure differential to move the gas through the cold trap, so the bigger the better.
-
A piece of 4” pipe, threaded at both ends. Drill holes in one cap, silver solder 5/8” flare adapters, attach a “dip” tube to one, reaching to bottom of pipe. Two layers of armaflex around a five gallon pail, place the pipe into the pail and fill with dry ice. Connect chiller to dip tube fitting, vac pump to short one, make two pipes, alternating and removing ice cube formed in pipe, vacuum pump oil lasts 3 hours instead of 15 minutes, more vacuum pumps the better, had 3 pumps and 4 pipes going, keeps you busy, but watch the water come out!
-
If an open drive chiller had large amount of water in it, I used to "dry run" it for 4-8 hours with no refrigerant in it. Remove the rupture disc or whatever relief device was on the evaporator vessel, and remove the high side float valve. Look at the normal flow path of the chiller and just make it a big vacuum cleaner temporarily. Of course dont do this on a chiller located outdoors if it is raining. This can cut your evacuation and dehydration timed from weeks to a day or two. I did this numerous times in chemical plants and some building chillers as a Carrier vendor rep. Even some hermetic chillers can be dry run, just watch your motor and bearing temps. Also as a caution, I would not dry run a chiller that runs on voltage greater than 480 volts if there is any appreciable amount of moisture in it. Dont operate 2300 or 4160, and especially a 6900 volt machine while it is wet inside. For them, you can use a vacuum pump along with a hear gun or two to pass dry, heated air through the chiller without running it. Heat gun in the rupture disc or valve opening and vacuum pump at a distant location pulling out. Use your head. Study the machine and realize that all you want to do is draw warm, dry air through it. There are also venders that can bring in a hot nitrogen truck, fired by diesel, and pipe it through a chiller, thereby raising its temperature to hasten drying. Use your head, its that big lump about 3 feet above your ass.