TEV sensing bulb & ext EQ tube placement

[kengineering]

Hi to all, It's been awhile. I'm working on a super custom display. It's physical shape and finish were designed by someone who gave little thought to the eletcric and refrig that will be required, so space is very limited. There is very little compromise to gain more room for the mechanicals. The difficulty I have now is this:
A TEV located where I have space, is feeding an evaporator for a small self select box. It will then exit this lower evap go up, 3 feet total, to the top of the cabinet, wrap several times around a stainless steel box,which will be insulated, making it a cold pan. Then back down to the starting point, near the TEV and out to a remote location. The sensing bulb and EQ tube will have to be two feet from the outlet of the cold pan. There is no space to get it closer. I plan to insulate the outlet of the lower evaporator line to the inlet of the cold pan. Then of course I would insulate from the outlet of the cold pan back to the remote condensing unit.
I have done this sort of thing before with surprisingly good results. I was able to maintain excellent temperatures in both the self select and the cold pan, which is used for condements- veggies and such, temps not critical, by only controlling the self select and allowing the pan to flood with out it's own control. What I have not done is place the sensing bulb and EQ so far from the outlet.
Any thoughts? One of a kind Ken

[monkey spanners]

Not the same size of system but in many of the dx milk tanks the txv is mounted at the rear of the tank and the evaporator inlet and outlets are at the front, so the expansion line could be anything between a couple of meters and eight meters and the same for the suction line out as it follows the same route, both lines are between the milk vessel and outer skin and so are cased in expandable foam, so no heat gains. Some have txvs with equalisers and some don't depending on size and manufacturer.

The only thing i wonder aboutin your system is oil logging, return from the lower evaporator to the upper second evap, i wonder if it would be better to feed the top one first?
I must add that i have no practical experience of such systems nor any skill in system design, i know at the lower temps in the evaps the oil will be thicker but on the other side the liquid refrigerant will dilute the oil also, i'm not sure which factor would be most in effect in your proposed system.

Maybe you could feed the cold well with a small capillary and the main evap with a txv.

Hopefully some more knowledgeable members will comment also.

Jon

[kengineering]

I have thought that oil return may be a problem and I might do just as you suggest. Feed the top first. However I have built 3 of these, that do not have the distance to the bulb issue, and they have had no problems in the 2 years in service so I kept it the same. I would like to split it up but have absolutly no cap tube experience. I wanted to built it with 2 TEV's but the boss says no for reasons I won't get into. Thank you for the response . Ken