My cascade.... MK7
Hello
What can i say, she's finnaly made. Maybe a short story...
I started making her @ 11.06.2003 (9 months ago), and was supposed to be a quick project made out of a A/C unit and my thrusty Danfoss SC10b. Well, the A/C leaked on the condenser. Later came the "mk2" part where the condenser was changed with the old A/C's evaporator, also a bummer (leaks). At that time i made a preety nice heat exchanger, made of 16m 8mm OD pipe and 16m 5mm od pipe, soldered by their sides.
Later i started making the "tower" version, after i got a Tecumesh RK5510 a/c compressor in my hands. After a first failed revision i decided to water cool the condenser, the system was supposed to be dual head and everything was supposed to be nice. It even didnt leak... well, than i had to change the oil in the compressors. The system was completelly disasembled, it took me a while to drain the oil from the compressors.
Now it was some time for miniaturisation, the MK5. It was supposed to be a small system, fitted inside a 50x30x50cm box, dual stage compressing in the II stage. Then my bad luck reached its top: a brand new condenser leaked like hell. After that i had a lil depression and wanted to throw that project away, during that time i made a gas turbine (jet engine) beacause i didnt know what to do with myself. After some time i was ready to start the project again.
The MK6 was almost a succes. Dual stage compressing worked ok, non of the compressors overheated, the injector worked flavlessly, the vacuum inside the evaporator was huge. As i said it ALMOST worked... the oil separators didnt work.
And now... finally after so much pain and misery comes the MK7...
Theres no insulation on the II stage yet, exept that everything is finished. The 2nd pic is a little outdated near the 2nd stage compressor (in the II stage) beacause the oil separators outlet leads directly to the accumulator.
But from the begening, the I stage:
How does the whole I stage look like...
The I stage compressor.
The condenser and fan assembly comes for my almost first refrigeration system wich i bought as a water chiller.
The filter is preety oversized but it also serves a accumulator purpose during startup
The hx is made of 16m 5mm OD pipe and 16m 8mm OD pipe... soldered together by their sides..
View on the filter + txv assembly
The suction line on the I stage....
The TXV is a ALCO TIHW, for R22, no mop..
Ok, now the II stage.
Lets start with the 1st stage compressor:
You can see the interstage deasuperheater and the SC10B...
Its oil separator
A sideshot
Now, the 2nd stage compression:
The assembly...
Its oil filter
And now, the evaporator:
The parts the evaporator consists of
The base
How its fitted
Almost made:
The injector assembly...
A hole for the temp probe
And after brazing:
Any comments needed ?
I use a almost identical evaporator in my friends system and works PERFECTLY!! So far its the best one i ever made/used, its only limitation is the way it can be mounted (only 3 possible positions)
Temps... Cant really tell the temps right now, i only tested it with R22. A cascade, with a 5psi condensing pressure, dual stage compressing is "a bit" of a overkill. To see what happens with higher head pressures i filled the system with some argon. The suction pressures remained exacly the same (about 20-22hg), the middle section pressures increased slightly (from a preety deep vacuum to a little less deep) and a 20 bar head pressure... The injector still throtelled properly @ 5V (nominal)....
Further tests this week with R23....
berkut
***edit*** changed the server, pics should work
Reply With Quote
Originally Posted by CompGeek
Bookmarks