The system is activated by
two electric timers. The first timer activates the heating element, which
liquefies the grease. After 60 minutes, the second timer starts the motor
powering the roller. The grease is picked up by the roller, cleaned off by the
wiper blade, and fed through a clear plastic tube into the collector box. The
motor and heater operate simultaneously for a set amount of time and then shut
off. The process can be easily observed by removing the system cover.
Inside the GRD are three
distinct areas, separated by baffles. The first area is the inlet, which serves
as a diverter to keep the in-rushing water from churning up the second area,
which is the grease retention area.
The second area has a
heater element, a stainless steel roller driven by the motor, and a wiper
blade. The water in this area is relatively calm, which allows the grease to
float to the top of the water. When the GRD motor is running, the grease is
picked up on the roller as it turns. The wiper blade cleans the grease off of
the roller and channels it out of the grease retention area into the plastic pipe
leading to the grease collector box.
The third area of the GRD is the discharge area.
Clear water from the second area flows under the baffle, at the bottom of the
GRD, while the grease, which is floating on top of the water, is kept out of
the discharge area by the baffle. From the discharge area, the water goes out
of the GRD and into the sanitary system. The outlet of the GRD is set lower
than the inlet so that there is a constant flow of water through the GRD
whenever the sinks are being used, whether the roller motor is running or not.