Scrolls and use in a casacde

[MeltedDuron]

Been offered the 2nd scroll that was left from the one i bought that sadly come a bit battered. No use to me in auto c really but a cascade i though they'd be amazing.

There single phase and ether 2900 or 34000 BTU, there is some conflict of spec here but im awaiting an LG rep to get back too me.

Would these 2 be useable in cascade other than being heavy as each comp is 30KG each!!! There ment to be R407c in an AC unit but im thinking a different gas could be used anyway as a first due to the displacment.

I Youtube for vids of scrolls and not a lot but nor could i find anyone that has used them in a cascade!

[[XC] gomeler]

Don't scrolls have a fixed compression ratio? Meaning you can't run a stupid low vacuum like with a high cc/rev rotary/reciprocating.

[MeltedDuron]

gomeler;3945262']Don't scrolls have a fixed compression ratio? Meaning you can't run a stupid low vacuum like with a high cc/rev rotary/reciprocating.

Not sure but these LG's have built it in HP and LP switches for there running. I can't find any specs on this at all hense my asking to an LG rep for the full comp info.

I guess some playing with one as a basic single stage is needed perhaps

[godmod]

Most scrolls have a bypass that openes at a certain compression ratio (e.g. 1:10)

[MeltedDuron]

So woth using or not? I have one as is already but worth getting the 2nd

[[XC] Lead Head]

One more thing, is that many scrolls are very sensitive to oil, so an oil sep is a must IMO

[MeltedDuron]

Maybe a simple single stage would be best then and not bother with the other one at all.

[quintus]

From that raport of 1:10 looks like a perfect compressor for auto-c.

[[XC] gomeler]

From that raport of 1:10 looks like a perfect compressor for auto-c.

Agreed. 1:10 in a single-stage is going to result in a terrible suction pressure. Autocascade though could do 1:10 with ease. Just use a buffer valve on startup to keep the discharge pressures down and it'll run happy :up:

[captaincascade]

Standard Thermo -150c autocascade freezers use a nice hearty scroll. Virtis lyophilizers use scrolls in a standard cascade. Scroll compressors grow distraught and quik to anger when you run them in a vacuum. And it has been proven that stress can shorten your life, therefore to insure a happy compressor with a posotive outlook on life, it is imparative to keep the suction in a positive pressure. One way to insure this (Which im sure most of you know) is to add a solenoid that fires into an expansion tank, controlled by a high pressure switch. Add a length of cap tube from the tank to the low side of system. This will not only help to keep the system from running in a vac, it will also help maintain low compression ratios by maintaining a lower high side (especially on start up). Scroll compressors are made for high efficiancy, high capacity. They really freaking move some gas. As for a standard cascade if you set-up the 1st and second stage right you can go for 5 suction and 150 to 175 head with r95 with temps of -85c. I do it all the time and the scroll will be secure in its station in life

john

[MeltedDuron]

Standard Thermo -150c autocascade freezers use a nice hearty scroll. Virtis lyophilizers use scrolls in a standard cascade. Scroll compressors grow distraught and quik to anger when you run them in a vacuum. And it has been proven that stress can shorten your life, therefore to insure a happy compressor with a posotive outlook on life, it is imparative to keep the suction in a positive pressure. One way to insure this (Which im sure most of you know) is to add a solenoid that fires into an expansion tank, controlled by a high pressure switch. Add a length of cap tube from the tank to the low side of system. This will not only help to keep the system from running in a vac, it will also help maintain low compression ratios by maintaining a lower high side (especially on start up). Scroll compressors are made for high efficiancy, high capacity. They really freaking move some gas. As for a standard cascade if you set-up the 1st and second stage right you can go for 5 suction and 150 to 175 head with r95 with temps of -85c. I do it all the time and the scroll will be secure in its station in life

john

John,

Part of that i wants that on my grave with it quoted from you. I think auto c just screams out too me even more now! Im going to play with some ideas now.