Cascade for John

[LukeXE]

Hi my friends

Few days ago John asked me about building for him cascade. I thinked about it and decided to do normal 2 stage cascade, but not in 100% normal.

I want to use ethylene as low stage gas, but thinked about high stage. Better HX temps = much better load temps on evap, am I right ? I will do first stage autocascading, even with -55*C under load on HX temps should be very good and I will have reasonable pressure to condense properly ethylene

It`s not problem for me doing first stage autocascading, like normal stage, but a little bit more pipes and phase separator and those are all differences, so why not try ?

For I stage I will use my autocascade just rebuild it a little bit and add second stage with 1HP rotary compressor and plate HX from Gray We will see how this baby will perform



and HX I will use...




tomorrow I will go for small shopping, I`ll buy some brazing rods, pipes, second highpressure cut-off switch and some more stuff

Stay tunned

BTW, we are thinking about 3 stager, so then we could use R14 as well !

[quent]

Nice going, I like 1st stage design

[symphy]

Damn, that is really... sick.
Don't forget to show enough of pics

Did someone build something like this before?

[LukeXE]

Don`t think so, maybe I`m wrong, but never seen that kind of unit here on XS.

I will make a tons of picks ! Promise

[wdrzal]

NO Safety Devices? like relief valves and your selling units. well you have been doing well ,But don't sell a unit you never built or your going to get yourself into trouble. Don't make promises your not sure you can keep.

I don't know the laws where you are but in the USA, pressure vessels must meet certain codes, just some thing to think about.

remember the "mother of all cascades" the craftsmanship was super but it had design problems and didn't work. Don't get in over your head. Did you do all the engineering ,as to flows,pipe sizes,pressuress,ect,ect,


Just some words of wisdom Walt

[LukeXE]

Fitted compressor and HX on auto-c base, tomorrow will braze some connections

[n00b 0f l337]

Good luck Luke.

[Brettbeck]

I think this cascade should perform great Luke ! Good luck!

Forgot to ask... why is it a 'turkey cascade' ??

[LukeXE]

wdrzal, don`t worry, for each stage I will install cut-off switches, as I have written...Must check prices of relief valves, as you can see on second photo, on I stage is installed Danfoss cut off switch, on II stage will be that same...

and about the design, it`s nothing special, just I stage autocascading, I don`t imagine any problems with it at all, what can not work good here ?

[n00b 0f l337]

Well there's a ton of load provided by the 2nd stage onto the "2nd stage" of the autoc. It may not be able to hold it.

[Big SturL]

Lol, ur sick...

[LukeXE]

We will see, ethylene is really easy to condense at all...



~ -45@15bar, even if I will have -55*C on HX it will be great...

Just for example, NoL, you said a ton of load, so why so many I stages of cascades is holding -40*C@ load ? I think there is about 200, 250W...maybe 300W at load, so if on co2 I had -65@155W, so with colder ethane I can achieve -55*C loaded at all....it`s not impossible, hard, but no impossible

[n00b 0f l337]

Nothings impossible, just improbably. I think you can do it Luke, but results on the HX may not be up to par, but the evap will sure be.

[Gray Mole]

Well that HX should be up to the job

I've had this same thought, and the only thing holding me back is that an Auto is so hard to hold load at very high capacity. At least it has been for me

My dream was a setup with 2 auto's though, one for high stage and one for low I think that may just stay a dream for a while yet

If you can crack that though, this will be a very very cold cascade, and at the very worst, converting it back to a conventional cascade should be very easy if you have any problems with the Auto part of it

I'll certainly be keeping my eye on your progress though Luke



Gray

[yotomeczek]

nice project

But I can't look at them carefullt because of Your avantar (nice semi-naked woman )

[n00b 0f l337]

Watch yourself yoto, thats Luke's woman!

[wdrzal]

Use relief valves, pressure cutoffs alone can't stop the pressure from rising if you overcharge and it starts to warm up.

A cut off switch will only shut off compressor, if you get a blockage and unit starts to warm ,you Must have a relief valve to release the pressure. They should never open if designed and charged correctly, but they are a must when using high pressure gases. safety first always.

[n00b 0f l337]

Most reliefs are one time use though and release refrigerant. I'd say a pressure cut off and then a relief staged 50-75psi later. This is good incase a blockage isn't the problem

[wdrzal]

reliefs are not one time use,when pressure is released they close and reset.

your correct about the pressure, the shutdown switch should be at least 50psi under the relief valve or more. The entire system is judged on the pressure of EVERY component in the system. Small tube is rated at much higher pressure than large tube. Expansion tanks and the like that has a lot of surface area is the greatest concern .But you need to now the maximum pressure rating of EVERY component.

[n00b 0f l337]

Right Wd, but I have seen reliefs (may not have been reliefs actually) that are one time use pressure releases. They hit a pressure pop and spill there contents. Maybe you should make a small guide to be linked into the sticky about buying and what to buy as far as safety releases on units goes?

[expansionvalve]

There a lots of different releif valves about, some have a brass main body with a soft solder low lead core that melts with temperature/pressure, these are definatly one time use, when it comes to sprung loaded valves try go for the better makes, some of the low end valves once popped seem to leak within 10% of the opening pressure while some of the better names seem to tolerate multiple opening/closing actions and remain leak free.

[LukeXE]

thanks Tom, for sure I will try R22/Ethane, no problem with that

So, I have back from AC shop, bought few parts for our project !



Special photo for wdrzal



New hosses for manifolds



suction piping & captube



some insulation

To be honest, I want to finish that unit before friday, because on friday I`m going to Cracow to computer thrades. Will charge it with R290/CO2 (I stage) and only CO2 with a little bit of R290 for second stage. That should give us -75*C loaded temps, when I will back, will try with ethylene and ethane

[quintus]

SoddemFX might be right about ethane and propane so watch out

GL!!!

[john_toscan]

luke my rig is waiting this little girl
nice job, I think we will reach our goal!

waiting to see results

[[cTx]Philosophy]

interesting read, subscribed to this just to see how it turns out, and I also agree about the avatar, she is a bit distracting