Eutectic beam/plate.

[alpha]

Hi all, I have a question with regard to eutectic plate.

I got an ice cream van to look at and the freezer boxes have eutectic plates if that what you call them. A steel shell with a solution inside with copper tubes immersed in the solution.

Anyhow, I got to swap out old mineral oil system for new polyester based equipment. I have to remove the plates and wash the old oil out so it's nice and clean upon reassembly and what I'd like to know is, what would the solution be inside exactly? When the system was first built it was running on R12 but now it's going over to 404a and I'm just wondering if the solution is man enough for the lower boiling point of 404a, I also do not know the history of the unit at all. It looks like the plates have been removed before and for all I know, someone else has topped the solution with plain water or something.

So, the plates have refill/drain plugs and I am just wondering, what would I refill with and more importantly how much? I would imagine if I filled to the top, when/if ice forms inside if there be too much solution it will burst a plate, how far would you fill them, what sort of percentage 70%?

I think that's about it, thanks for any help....

[taz24]

Hi all, I have a question with regard to eutectic plate.
I think that's about it, thanks for any help....

They are just filled with an antifreeze.
In the case of ice cream, food friendly.

Cheers taz.

[The MG Pony]

Propylen glycol mixed to the spec of the R404a

IE cut the glycol with water so it sort of freezes at the R404a evap temp.

[Peter_1]

Well, not exactly, the purpose of an eutetic plate is to make that the solution solidfies at a predetermined temperature which is +/- 10 K lower then the desired room temperature.

The compressor must shut off ( LP contol) at +/- 6 to 10 K lower then the eutectical point.

The solution has nothing to do with the sort of gas, it only boils as low as the compressor pulls it to a certain pressure.

Even if you change from R12 to r404a, evapoaratin pressure must remain +/- the same, but pressure will change of course.

Make sure when you fill them that the plates must be filled completely but you must push/flatten them a little bit so that there is some space toe expand. See explanation in a previous post of some months ago.
http://www.refrigeration-engineer.com/forums/showthread.php?t=2665&highlight=eutectic and http://www.refrigeration-engineer.com/forums/showthread.php?t=7615&highlight=eutectic

Don't overload the R404a compressor on start-up.

[NH3LVR]

Peter_1 as usual has it right.
I did one job with Dole plates years ago, for a friend.
Check out the info at www.doleref.com.
As I rememember the pressure drop across the plates was rather large, and could result in rapid cycling if the compressor applied was too big for the application.
It is a excellent application for a hot gas bypass system. This allows you to keep the compressor running until the Eutectic solution is completly frozen.
The plates seem to have fallen out of favor because of the weight. They were used extensivley years ago by plugging them into a NH3 system at night.
The only problem was when the driver forgot to disconnect before driving away.

[Peter_1]

Just noticed now, look once to the bottom of this thread 'Similar Threads'

[Peter_1]

On the previous links, there are some pictures of plates we made in the past.

[alpha]

Thanks very much for all your help, most informative.
War begins tomorrow :D

[Peter_1]

Let us know how the job went.

[alpha]

ok, so far the job has gone, a shade downhill, today I have written off the plates, leaking nitrogen into solution from inside, on the upside I shall soon fit some nice new shiny ones :)

[Soko]

Peter, can your company make eutectic plates by given measures? If you can please contact me for further details.

If they dont do that, do you know some European manufacturer that makes those. Plates should be used in Framec truck bodies for ice cream transport.

[Peter_1]

Sure we can do this but I don't think we will be competitive due to the transport and the expensive labour hours compared to your country.

But I can help you with the design so that you can make those in your country. Isn't that a better proposal?

[Soko]

Can we continue this conversation privately? I think that you, as moderator, should be able to send me an e-mail.