RS COMPACT FREEZE TUNNEL, Руководство по эксплуатации и обслуживанию

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OPERATION & MAINTENANCE MANUAL
CompactFreezer
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4. Start the exhaust blowers. Check for proper blower motor rotation (three module only). Radial
blade blowers have a small suction even when rotating backwards. Motor should rotate so the
blower blades move towards exhaust spiral outlet.
5. Start the conveyor drive(s). Check for proper tracking of the individual conveyor belts on the
sprockets. Adjust the belt tension or change the belt lengths if required. Adjust the scraper bar(s)
as required to just touch the conveyor belt.
6. Start the circulating fans. Check for proper rotation (all in counterclockwise direction viewed
from above). Check that dynamic braking is operating properly. Should stop in 1 sec.
Check for motor overheating due to binding in the bearings or excessive vibration.
7. Turn off the fan motors and the instrument power after operating all LN
2
valves.
8. Shut off module fan motor before opening the module door to check for proper operations of the
injection headers. All active nozzles should have a uniform flat spray pattern. All nozzles should
be aligned to blast down on the conveyor at approximately a 45° angle.
6.3. OPERATING TEMPERATURE
The normal operating temperature of the Cabinet Freezer tunnel can be adjusted from +50°F to ‐ 125°F
(+10°C to ‐1 20.5°C) for most products for optimum product quality, maximum freezing capacity, and best
operating efficiency.
Liquid nitrogen is used as an expendable refrigerant, unlike ammonia or Freon which is recycled in a
closed loop system. The liquid is stored in a vacuum jacketed vessel at typical conditions of 50 psig and
‐
300°F ( ‐184 °C). The low temperature, high capacity freezing available with LN2 is obtained by expanding
the liquid through the injection nozzles.
The liquid nitrogen is converted into a mist (water ‐ like droplets) by the spray nozzles. The available
cooling from the LN2 is achieved by the droplets expanding from the heat of the product and vaporizing
to a gas. The remainder of the cooling is gained by warming the resulting cold gases to the exhaust gas
discharge temperature.
Even though LN2 is approximately ‐ 300°F ( ‐184 °C) at the nozzle, we prefer to control the temperature in
the freezer to be no colder than ‐ 125°F (-120.5°F) for the prevention of damage to equipment, efficient
economics and safety to personnel.
The high velocity N2 pressure and circulating fans in the Cabinet Freezer promote the rapid cooling and