herefishy stays up late - builds cascade

[herefishy]

pics -

[herefishy]

another

[herefishy]

This is preliminary results, no fiddling or "tuning" has occured. I assembled the machine in about 14 hours of time, not including picking up materials (but including cutting, welding, and assembling the chasis) :D

reading is in Celsius (-85C = -125F)

[EmineM]

looks really good O_O

[Donebalp]

AWESOME

[Epsilon]

Originally posted by herefishy
This is preliminary results, no fiddling or "tuning" has occured. I assembled the machine in about 14 hours of time, not including picking up materials (but including cutting, welding, and assembling the chasis) :D

reading is in Celsius (-85C = -125F)

to me, it says "mV" instead of C :D

[DaBit]

External tempsensor module. I also built one years ago with a couple of LM35 sensors.

Herefishy: what refrigerants?

[herefishy]

Originally posted by DaBit
External tempsensor module. I also built one years ago with a couple of LM35 sensors.

Herefishy: what refrigerants?


R-134A / R-13

[herefishy]

It seems that I need to restrict the oil return from my separator. I thought that the separator had an internal oil control (float or what-have-you), but apparently not. I had to pinch the oil return line in order to start cooling.

Do you think that I should employ some cap tube for this purpose?

[DaBit]

Wow, R13. That's one hell of a nice refrigerant. Much lower compression ratios than R23 or ethylene. Easy to condense.

My current oil sep uses a float. If yours don't, I would dimension the captube to 5-10% of the main captube flow. This ensures sufficient oil return (small hermetics do not even spit out 5%/95% of oil/refrigerant, at least my Danfosses won't), and a not too large loss of capacity since when there is no oil, vapour is pushed through. Not much mass is pushed through that way, giving a neglectible capacity loss.

[herefishy]

Yeh, capacity loss is (a) concern. 5%-10% of cap tube flow? I don't understand.

[Russell_hq]

I just read an article about oil flow in the caplillary tube. When it mixes with your refrigerant, the liquid "thickens up" (viscosity increases) and reduces the mass flow through the capillary tube. So you are going to need a shorter tube or a good oil separator.

[herefishy]

Well, i've got a good oil seperator..... I just need to regulate the flow into the compressor crankcase. The separator has no "control", so-to-speak. I have employed 12' of .028" cap tube as my expansion device.

Do I use 4 inches or 5 feet of cap tube for the oil return, I'm wondering?

[Gary Lloyd]

What kind of oil is in your compressor?

[herefishy]

Originally posted by Gary Lloyd
What kind of oil is in your compressor?


POE

[Gary Lloyd]

R13 needs mineral or alkylbenzene.

[herefishy]

originally posted by Gary:
R13 needs mineral or alkylbenzene.





National Refrigerants website pertaining to polyolester lubricant product:
Polyolester
Designed specifically for HFC refrigerants but miscibile and compatible with all fluorocarbon refrigerants, mineral and alkylbenzene lubricants. Packaged in metal containers.

[Gary Lloyd]

A friend had a problem recently with R408A, where the AB oil was too compatible with the refrigerant and it blew by the separator, and held the float open. We had to add some mineral oil to get the separator to work. R408A loves AB oil. I don't know if this is the same problem, but something to think about.

At the National site, when you go to the R13 page, it only says mineral or AB.

[herefishy]

Originally posted by Gary Lloyd
At the National site, when you go to the R13 page, it only says mineral or AB.


Since the miscibility of the POE is universal (with the flourocarbon refrigerants), as could be interpreted by the description of the lubricant by the manufacturer (per previous post), the miscibility of the POE is assumed (to be appropriate). Whereas the AB and mineral oil (mostly) are limited in their application, such compatibility with those lubricants must be defined.

That's the way I always looked at it. ;)

Cheers!

[Bra!nFreeZe^]

D00D I really love the way you have build your cascade...It looks pretty clean to other cascades in this forum for being alot smaller,because of the rail that you mounted it on! really nice!

[herefishy]

Thanks Bra!n .. :)

I've had a lot of time to think about it, and paid special attention to the others who are building cascades (that know more than I about it).

Thanks to those special knowledgeable people... :thumbsup:

[herefishy]

BTW.. I decided that I am going to employ a timed interval solenoid valve for my oil return scenario. The timed event will decrease the need to super-engineer my return line pressure drop, and prevent my sacrificing any capacity on a contious basis via by-passing the evaporator through the oil separator.

Cheers!

[Gary Lloyd]

I have never heard of a commercial oil separator that didn't have a float, although such a thing may be possible.

[herefishy]

it's a temprite 300 series. When I got it from my supplier, no papers or anything. The temprite website sucks.... I dunno.

It rattled like it had a float. I may call temprite back, again.

I certainly assumed it had float when I made the purchase, and did not anticipate this *problem*. Of course, my middle name isn't Mr. Oil Separator, either. :p:

[paul007]

What compressors are those Mr.Fish? They either look small or the whole setup is very big?

[herefishy]

Okay, I got my vendor to fax the temprite infor to me. The separator has NO float. It was designed for tiny systems, and presumeably the lack of the float mechanism reduces oil carry-over for 99.999% effectiveness of oil removal.

So, I will emply some means to control the oil return. I like the timed interval solenoid idea. Maybe just a bit of the 3/16" O.D. copper that I have would be adequate for 2 second shots of oil return every hour, or so. perhaps incorporating a timed by-pass, so the machine doesn't return oil, and raise the crankcase pressure in the heat of battle, while you're OC'ing. LOL

[herefishy]

originally posted by Paul007:
What are those compressors, herefishy?



They are my trademark Tecumseh *TPA* compressors, 1/4 horsepower.

[runmc]

nice job mark

The Temprite 340 is a coalescing oil seperator, and doesn't have a float. Coalescing seperators only have filters. Well the two small one I have, don't have floats anyway. I can't say about all of them.
I'm glad you had the problem first. LMAO :D

Maybe a small seperator with a float would be the ticket.

Actually , I think they're designed for recovery systems.

[captaincascade]

134a?
what is your interstage temperature?

[kommando]

Niiice, reckon you could resize the pics please?

[herefishy]

Originally posted by captaincascade
134a?
what is your interstage temperature?

MY interstage temp is -20F to -23F. Of course that is *unloaded*, in my 50degF shop. I have a thermostat (operating in *heating* mode) that is sensing the first stage suction return exiting the interstage, to enable the second stage when it hits -20F, and to disable the second stage if the interstage rises to 0F.

[herefishy]

Originally posted by kommando
Niiice, reckon you could resize the pics please?

The pics are re-sized. Sorry about that. I only display the links to pics while browsing, and I didn't have any problems when I opened the pics a new window. I hope that the re-sized pics are better. :)

[herefishy]

Originally posted by runmc
Coalescent seperators only have filters.

After having received the temprite literature on the oil separator products, I have learned that there a coalescent oil separators with floats (namely the 900 and 920 series). It seems that there are two type of oil seperators - Coalescent, and impingement.

The coalescent oil separator slows the refrigerant velocity, and runs the mass flow through a fine screen that is illustrated as something that reminds me of the screen on a cylindrical bug zapper. :p:

Presumeably (as advertised) the coalescent filter screen captures solids as small as .3 um (microns), and aerosols (oil) down o .001 um. The coalescant filter material is described as a borosilicate glass matrix.

The impingement type oil seperator circuits the gas through two chambers. In the second chamber a screen is strategically placed whereas the suspended oil in the refrigerant *impinges* upon the screen. I guess kinda' like throwing spagetti against the wall. LOL :p:



Cheers!

[Gary Lloyd]

I wonder if a CPR followed by a long cap tube would do the job. The CPR would reduce the pressure at which the oil is pushed through the cap tube. When the oil separator is empty, there would only be a very small flow of hot gas.

[herefishy]

Originally posted by Gary Lloyd
I wonder if a CPR followed by a long cap tube would do the job. The CPR would reduce the pressure at which the oil is pushed through the cap tube. When the oil separator is empty, there would only be a very small flow of hot gas.

Hi Gary. The Engineer at Temprite suggested a pressure regulator as one means of accomplishing the feat. I am having a 1/4" solenoid valve picked up for me now, for the oil return circuit. I just don't want to give up a single watt/hour in the oil return department, so I choose the interval option.

Cheers!

[DaBit]

I also did that in my R507/R410A cascade oil sep (http://www.icecoldcomputing.com/text/show_page.php?id=76). A single shot every minute or so worked fine for me, and was hardly noticeable in evap temps.

[herefishy]

Okay.... I ended up installing a receiver for an expansion tank, otherwise it's all buttoned up.

Watch the boards... *Team Puss* will be benching with it this weekend!

:D:

[herefishy]

Hi,

I turned the *view images* option back on in the control panel, and I realized how awful those pics were that I posted on the first page of the thread. I think that the pics are easily viewable, now...

sorry 'bout that..

Cheers!