Vogt P18AL TUBE-ICE, Service Manual

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P18AL Service Manual
HOW YOUR TUBE-ICE MACHINE WORKS
3/6/2007
4-2
The freezing period is completed by action of the freeze timer in the control panel (or an optional
freezer pressure switch). The water pump (5) is stopped and solenoid valve “A” (25) is closed. The
thawing period then begins. The thaw gas solenoid valve (18), sometimes referred to as the “D”
valve, is opened, the cutter motor (3) is started and the harvest timer (T) is activated. Warm gas
from the receiver is discharged into the freezer through valve (18), thereby slightly thawing the outer
edge of the ice which drops on the rotating cutter for sizing. See “Freezer Period and Harvest
Period” for more detailed description of operation.
Freeze Period. The Tube-Ice
®
is frozen inside the stainless steel tubes in the freezer (1) by the
direct application of refrigerant to the shell side (outside) of the tubes. The ice is produced from
constantly recirculating water during the freeze period. As the ice thickness increases, the freezer
suction pressure decreases. At a set time, the freeze timer initiates the harvest period. The harvest
period may also be controlled by means of a freezer pressure switch that can be adjusted to get the
correct thickness of ice (this is an optional control device – consult the factory for information).
Harvest Period. When the freeze timer (T2) contact closes, a control relay (1CR) is energized. The
“1CR” relay stops the water pump and starts the cutter motor. The “A” solenoid valve (25) closes,
the “D” solenoid valve (18) opens and the thaw timer (T) is energized. As the ice releases and drops
through the rotating cutter and onto the cutter disc, it is discharged through the side opening of the
water tank. The harvest timer (T) is to be set for the time required to discharge all the ice plus 30
seconds longer (usually 2 to 2 1/2 minutes).
! CAUTION !
Make sure all the ice clears the freezer with at least 30 seconds to spare
before the next freeze period begins. This is to prevent refreezing.
! CAUTION !
1 Freezer 16 Suction Connection, 2” Flange
2 Control Panel 17 Freezer Pressure Gage
3 Cutter Motor 18 Thaw Gas Solenoid Valve
4 Cutter Gear Reducer 19 Thaw Gas Pressure Gage
5 Water Pump 20 Strainer Purge Valve
6 Water Distribution Chamber 21 Strainer
7 Freezer Safety Valves 22 Oil Trap
8 Three Way Valve 23 Refrigerant Float Switch
9 Hand Expansion Valve 24 Liquid Line Stop Valve
10 Thaw Gas Stop Valve 25 Liquid Line Solenoid
11 Ice Discharge 26 Liquid Line Strainer
12 Water Tank Overflow, 2” FPT 27 Flush Water Solenoid Valve
13 Cutter/Tank Assembly 28 Water Tank Drain Valve, 1” FPT
14 Freezer Purge Valve 29 Make-up Water Inlet Valve, ½”
FPT
15 Lifting Lug 30 Refrigerant Charging Valve
Piping Nomenclature
TABLE 4-1