Flooded type Evaporator Cooling control, how?

[Levent]

I am a food engineer curious about refrigeration system in my plant.

I have several scraped surface heat exchangers (cylinder within cylinder), kind of flooded type evaporator.There is refrigerant, ammonia, outside the inner cyclinder.
Inside the inner cylinder there is high temperature fat to be cooled down to be solidfied and make margarine.
You can see the very simple illustration here ; https://ibb.co/3YPt350

There is motorized danfoss icm valves for ammonia inlet and outlet.
inlet valve keeps liquid ammonia at constant level.
I increase or decrease degree of cooling by controlling outlet valve.
My evaporation temperature depends on aperture of it. So, i change boiling point of ammonia from 0 C to -20 C /3.3 bar to 0.8 barg dependent on the fat product.

My question is, where is expansion valve in my refrigeration cycle?
Is it my evaporataor inlet valve that i keeps constant level?
Is it my ammonia outlet valve that i change degree of cooling?
Is it somewhere else after condenser outside the building?

If it is my outlet valve it means expension valve is after evaporator, or evaporator itself
which doesnt make sende in terms of reverse carnot cycle, it should be befor evap.


So as you see i am in a deep confusing, may be you can help me.

Thank you in advance.

[seanf]

It sounds like the inlet ICM is your expansion valve, and the outlet ICM is acting like an evaporator pressure regulator.

Is the pipework going from the evaporator to the outlet ICM taken from the top of the evaporator?

If youve got pipework drawings or photos of the plant it might help others to identify how your system works. Its not always as simple as, compressor -> condensor -> expansion valve -> evaporator.

[Levent]

You are totally right!
my outlet valve is actually pressure regulating valve ; i didnt know about EPR before.
Of course inlet valve is expansion valve.
You helped me a lot. thank you so much.

[Glenn Moore]

The ICM valve on the inlet to the evaporator controls the high pressure liquid coming from the condenser, the ICM valve opens and closes to keep the liquid level in the votator drum at a constant level,
The ICM valve on the outlet of the evaporator simply controls the pressure/ temperature inside the evaporator by controlling the vapour pressure inside the drum . The ICM valve can be controlled via a pressure signal , a temperature signal , or the current of the fat pump motor.