Operation. Scotsman DCE33

DCE33

OPERATION

How does the machine make ice?

There are two distinct cycles: freeze and harvest.

1 freeze cycle + 1 harvest cycle = 1 batch of 8 cubes.

The Freeze cycle happens when water is sprayed against the freezing surface. The Harvest cycle is when the ice is released and water enters the machine. A complete cycle takes about 30 minutes.

Freeze: During the freeze cycle the compressor is pumping refrigerant, the fan motor is blowing air, and the water pump is circulating water. As the refrigerated surface absorbs heat from the water sprayed against it, that heat is moved to the area where the fan is blowing air. The heat is transferred to the air, and the warmed up air is discharged from the ice machine. At the same time ice is forming on the refrigerated surface (located at the upper back of the machine). When the refrigerated surface gets cold enough, the ice machine’s timer will begin to turn. When it turns far enough, it will stop the freeze cycle and begin the harvest.

Harvest: During the harvest cycle the compressor is still operating, but the spray pump and fan motor have stopped. Two other components have been energized; the hot gas valve and the inlet water valve. These two valves open and warm up the freezing surface, allowing the cubes to fall into the bin. The timer is still turning, and when it gets to the end of the harvest cycle, the freeze cycle will restart.

How does the machine use water? The ice machine begins with a fixed charge of water that is contained in the reservoir. As the water is sprayed against the freezing surface, the part of water that does not contain mineral impurities will freeze and stick to the ice cup molds. The water containing impurities falls back into the reservoir. Gradually, during the freezing portion of the ice making cycle, the water in the reservoir will become highly concentrated with mineral impurities.

During the harvest cycle fresh water flows into the machine to dilute the reservoir water and to rinse the concentrated minerals down the drain.

Schematic Diagram - Shown In

Harvest Cycle

Water

Inlet

Cube Molds

Evaporator

Weep

Hole

Spray Jets

Water Tube

Reservoir

Condenser

Compressor

August 1995

Page 13