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View Full Version : "automatic" expansion valve (AEV or AXV) in flake ice machine







marco59
18-12-2016, 12:52 AM
Hi all,
I am trying to "fix" a R404A flaked ice machine that has been composed on site.
There is a Dorin H220CC (today H221CC) compressor (3000 to 3700 W at -20C evap) and an air cooled condenser at least 30% oversized as it was in a tropicalizated condensing unit with a Dorin compressor H300CS (today H301CS) that is a low temp unit with 4700 to 5800 W at -20C evap with 5.7 lt. receiver.
The evaporator is an horizontal rotative type and it is in good shape
The metering device is an Honeywell AEV (constant pressure valve) internally equalizated AMV 0003
The suction pressure is adjustable within a range of 1 Bar
There is a solenoid valve before the valve.
Thats all...no suction accumulator nor condenser fan speed controller .no pressure switches..Nothing else but a sight glass and a motor overload contactor :rolleyes:
Obviosly it suffered from massive liquid slugging to starved evaporator but the compressor survived until now.( The machine is in an outdoor enviroment in Italy )
I added a condenser fan speed controller and rised the discharge pressure to 17 Barg (38C)
and founded a near 0K superheat at 2,2 Barg suction So that ice prodution is ok.
Now I should have reached the maximum compressor capacity at that suction and discharge temperatures...Please tell me if I am right till now...
If yes I believe that any sistem using AEV valve must have a suction accumulator...Am I right?
If I will add a suction accumulator may I leave in place the liquid receiver? How to find the correct charge to prevent liquid to fill up the suction accumulator in an event ov very low load condition?
Apart from choosing the correct size of the suction accumulator to have a good oil return,what about
possible liquid return at compressor startup? (no problem now)
Could you suggest a tipical setup using an AEV?
Thanks for reading
Best regards from Italy
Marco