Greenheck is leading the industry in grease abatement. Innovative
filter designs and a method of testing for cooking emission particle
sizing has allowed Greenheck to develop the most efficient mechanical
filters on the market. All of the filters are UL 1046 listed and
most filters are available in aluminum or stainless steel. Sizing
options are 16 x 16 inch, 16 x 20 inch, 20 x 16 inch, and 20 x
20 inch.
The graph shown represents the efficiency of a waterwash hood.
Each filter type has a graph similar to this.
The overall shaded area represents the amount of grease emissions
from the cooking equipment.
The dark shaded area represents the amount of grease taken
out of the airstream by the filter.
The lightly shaded area represents the grease particulate
that escaped past the filter.
The ratio of dark shading to light shading at a particular
particle size is represented by the fractional efficiency curve.
Filters with higher efficiencies will have more of the total
shaded area darkened.
Water Wash / Dry Cartridge Hoods (GW and GK Series)
Water
wash hoods have the filtration system built into the hood and
are 50% efficient at about 6.5 µ. The point at which a filter
is 50% efficient is called its cut point. This shows that the
water wash / dry cartridge hoods are still dependent on inertial
impaction. Their higher efficiencies than the baffle filter are
also reflected by a much higher static pressure. Typical pressure
drops for a 9 ft. x 4 ft. hood at 2050 cfm will be 1.1-1.3 in.
wg.
Baffle Filter (GH Series)
The efficiency curve for the baffle filter and the cartridge
filter shows that at 8 µ its ability to remove particulate
is 30%. Baffle filters use inertial impaction, which is
the principle of the particle’s momentum throwing
the particle out of the airflow as it changes direction,
to remove grease from the airflow. Typical pressure drops
for a 9 ft. x 4 ft. hood at 2050 cfm will be 0.5-0.6 in.
wg. Available in aluminum or stainless steel.
The Grease-X-Tractor™ is 50% efficient at 5 µ.
A cut point of 5 µ is typical of a centrifugal filter.
Its efficiency improves rapidly above 5 µ and drops
below 5 µ. The use of centrifugal force rather than
two-dimensional impaction allows the efficiency to be improved
without a high penalty in static pressure. Airflow enters
the filters louvers and is spun in a chamber until it exits
the back of the filter. Grease particles are thrown from
the airflow during its helical path. The velocity of the
airflow determines how small of particle can be removed.
The static pressure is between a baffle filter and a water
wash hood. Typical pressure drops for a 9 ft. x 4 ft. hood
at 2050 cfm will be 0.7-0.8 in. wg. Available in aluminum
or stainless steel.
The Grease Grabber™ uses a centrifugal type filter
as the primary stage of filtration along with a packed bead
bed filter as the second stage. Interception is the main
filtration mechanism which works by adsorbtion of grease
particles as they come in contact with the packed bead bead.
The Grease Grabber has a cut point at 2 µ. Its efficiency
increases to near 100% at 7 µ and drops for particles
smaller than 2 µ. This reduction in the size of particles
that can be removed indicates that the Grease Grabber uses
a combination of all filtration mechanisms. The static pressure
drop is the highest of the filters evaluated but only slightly
higher than water wash. Typical pressure drops for a 9 ft.
x 4 ft. hood at 2050 cfm will be 1.1-1.3 in. wg. Available
in stainless steel. Grease Grabeer filtration can be retro-fitted
to many other hood models.
Water
wash hoods have the filtration system built into the hood and
are 50% efficient at about 6.5 µ. The point at which a filter
is 50% efficient is called its cut point. This shows that the
water wash / dry cartridge hoods are still dependent on inertial
impaction. Their higher efficiencies than the baffle filter are
also reflected by a much higher static pressure. Typical pressure
drops for a 9 ft. x 4 ft. hood at 2050 cfm will be 1.1-1.3 in.
wg. 
