Vogt HEC-10, Руководство по обслуживанию

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HEC-Series Service Manual
HOW YOUR TUBE-ICE MACHINE WORKS
10/21/01
4-1
4. How Your Tube-Ice Machine Works
Principle Of Operation. The manual operation of the machine is controlled by the “Ice” and “Start”
switches located in the switch box of the freezing unit. The automatic operation is controlled by the
PLC and ice bin thermostats which will automatically stop and start the freezing unit by the level of
the ice in the storage bin (NOTE: See “Ice Bin Thermostat Bulb Installation” for instructions on
installation of the control bulb of the ice bin thermostats FIGURE 3-14). The type ice produced
(cylinder or crushed) is determined by the position of the ice selector switch located in the switch box.
The control wiring is arranged so that the unit will stop only upon the completion of a thawing period
and partial pumpdown cycle whether by action of the “Ice” switch or the ice bin thermostats.
The “Clean” switch must always be set in the “Off” position (not illuminated) during normal ice-
making operation. It is set on the “Clean” (illuminated) position only when the equipment is to be
cleaned or pumped down as outlined in the “Cleaning Procedure,” and “Total Pump-Down
Procedure”, Section 9, and instructions attached to the machine.
If it should become necessary to instantly stop the machine, either the external disconnect switch,
cutter overload switch, or pump overload switch must be turned off.
FIGURES 4-1, 5-2, & 5-3 illustrate the piping diagram of the refrigerant and water circuits of the
Tube-Ice

machines with numbers for easy reference. Throughout this manual the numbers you see
in parentheses refer to the numbers in this piping schematic.
The freezer (2) is a shell and tube-type vessel. During the freezing period, water is constantly
recirculated through the vertical tubes of the freezer by a centrifugal pump (6). Make-up water is
maintained by a float valve (12) in the water tank (7). Solenoid valve (20), sometimes referred to as
the “A” valve, is open and solenoid valve (18), sometimes referred to as the “D” valve, is closed.
Refrigerant gas from the top of the freezer (2) passes through the accumulator (88), the heat
exchanger (13), the CPR valve (100), and to the compressor (3) which discharges it into the
condenser (15). Condensed liquid refrigerant from the condenser flows through the liquid side of the
heat exchanger and into the receiver (15R). Liquid refrigerant from the receiver flows through the
filter/drier (46), the thawing chamber (16) of the freezer, the strainer (43), “A” valve (20), expansion
valve (17), and into the freezer, thereby completing the freezing circuit.
At the completion of the freezing period, thawing is started by action of the freezer pressure switch in
the control panel. The water pump is stopped and solenoid valve “A” (20) is closed. After a time
lapse of seven seconds, solenoid valve “D” (18) is opened, the cutter motor (5M) is started and the
harvest (thaw) timer (FIGURE 9-6) is activated. Warm gas from the receiver is discharged into the
freezer through valve (18), thereby slightly thawing the ice which drops on the rotating cutter for
sizing. Cylinder ice will be discharged through the right half-section of the ice discharge chute when
viewing the Tube-Ice
®
machine from the front. Crushed ice will be discharged through the left half-
section of the ice discharge chute.
Air-cooled machines have a solenoid valve (53), sometimes referred as the “X” valve, in the
compressor discharge line, and a check valve (101) in the liquid return line to the receiver. These
valves prevent the migration of refrigerant to the condenser when the machine is not operating.