Overhead ventilation system for use with a cooking appliance

An overhead ventilation hood for a ventilation system of a conventional cooking appliance. The hood includes a housing with a planar base surface and a recessed interior arrayed in a downwardly facing manner which is defined by a first side, a second spaced apart side, a first interconnecting end and a second interconnecting end. Intake and exhaust openings are formed through the housing proximite the first and second sides. The ventilation system includes a first blower mounted in communication with a first length of ductwork extending to the intake opening to provide a stream of pressurized intake air and a second blower mounted in communication with a second length of ductwork extending from the exhaust opening to provide a stream of pressurized exhaust air. A supply plenum chamber is established along the first side of the housing interior and includes elongate and planar shaped channeling walls and a planar shaped diffuser for regulating a flow of the stream of pressurized air into a central open interior of the housing. An exhaust plenum chamber is established along the second side of the housing interior and includes an elongate planar shaped and angularly mounted filter. Combinations of heat, airborne grease and smoke are issued upwardly from the cooking appliance within the open interior of the hood and are discharged through the filter and within the stream of exhaust air concurrent with intermixing with the regulated flow of the stream of intake air. An elongate and planar shaped deflector extends in proximity to a bottom edge of the angularly disposed filter at a further specified angular orientation and causes a deflected stream of exhaust air to be redirected towards the filter for evacuation from the housing.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to overhead ventilation systems for 
use with ovens and other cooking appliances and, more particularly, to a 
ventilator hood for removing heat, airborne grease and smoke from such 
cooking appliances while creating an airflow equilibrium within the hood 
so as to minimize the loss of quality interior air. 
2. Description of the Prior Art 
The prior art is well documented with ventilation hoods utilized in 
ventilation systems for facilitating the removal of heat, airborne grease 
and smoke from the cooking devices, and in particular commercial cooking 
equipment such as ranges, pizza ovens and the like. The objective of each 
such ventilation system is the ability to evacuate the undesirable 
by-products of the cooking appliance in such a manner so as not to affect 
the air quality established within the room enclosure surrounding the 
oven. This is preferably accomplished by providing a separate air inlet to 
the ventilation hood in addition to the exhaust outlet in the attempt to 
achieve an air equilibrium condition within the hood so as not to evacuate 
the quality conditioned (heated or cooled) air within the hood. 
U.S. Pat. No. 5,713,346, issued to Kuechler, discloses an exhaust hood 
ventilating system which utilizes both intake and exhaust blowers and 
means for regulating the volume of air introduced within the ventilation 
hood. Additional means are disclosed for creating a vortex flow within the 
hood enclosure and for diverting outdoor intake air into a surrounding 
kitchen area for ventilation before it is passed back to the hood for 
exhaust to the outdoors. 
U.S. Pat. No. 5,467,761, also issued to Kuechler, teaches a further 
variation of a filtering apparatus in which a supply air plenum is 
provided with perforated balancing plates and deflector plates which 
perform the functions of modulating an incoming air flow. A filter is 
arrayed in proximity to an exhaust of the apparatus to facilitate removal 
of the by-products of appliance. 
U.S. Pat. Nos. 4,944,285 and 4,896,657, both issued to Glassman, teach 
variations of an exhaust hood for a pizza oven which induces exhaust 
materials into the exhaust stream by creating high velocity flow of 
outside air into the hood. According to the '285 patent, an intake fan 
forces outside air into a pair of intake plenums located along opposite 
sides of the hood, creating two high velocity air streams flowing toward a 
central exhaust plenum and an exhaust fan drawing air into the exhaust 
plenum and through inclined grease filters. According to the '657 patent, 
a central intake fan forces outside air into a central intake plenum and 
through air deflectors to redirect opposite extending air streams through 
exhaust plenums on opposite sides of the hood. Exhaust fan draw air into 
the exhaust plenums and through inclined grease filters. 
A shortcoming of the prior art is the inability to create a controlled 
equilibrium environment within a ventilation hood assembly for 
facilitating the evacuation of heat, airborne grease, smoke and odors 
emitted from the cooking appliance while at the same time preventing the 
loss of quality interior conditioned air through the hood exhaust or the 
substantial introduction of outside supply air past the hood enclosure and 
within the room interior. 
SUMMARY OF THE PRESENT INVENTION 
The present invention is an overhead ventilation hood for use within a 
ventilation system for a cooking appliance. The ventilation system 
includes a first blower mounted in communication with a first length of 
ductwork extending to the hood and a second blower mounted in 
communication with a second length of ductwork extending from the hood. 
The hood includes a housing having a planar shaped base secured at an 
elevated location above the cooking appliance, the housing having a 
recessed interior which is arrayed in a downwardly facing manner and which 
is defined by a first side, a second spaced apart side, a first 
interconnecting end and a second interconnecting end. 
An intake opening is formed through the housing base proximate the first 
side and is secured to the first length of ductwork for receiving a first 
stream of pressurized intake air. An exhaust opening is formed through the 
housing proximate the second side and is secured to the second length of 
ductwork for exhausting a second stream of pressurized exhaust air. 
A supply plenum chamber is established within the recessed interior of the 
hood enclosure along the first side and is constructed of first and second 
elongate and planar shaped channeling walls which are interconnected by a 
planar and elongate diffuser including a plurality of individual apertures 
formed therethrough for regulating a flow of the first stream of intake 
air within the central open interior. An elongate and arcuate shaped air 
flow distribution element is mounted upon the second planar shaped 
channeling wall and functions to cause the first stream of pressurized 
intake air to be equally distributed between the first and second 
interconnecting ends within the supply plenum chamber prior to passing 
through the diffuser. 
An exhaust plenum chamber is established within the recessed interior along 
the second side and includes an elongate and planar shaped filter which 
extends between the interconnecting ends and which is mounted by first and 
second opposed and elongate brackets in an angular orientation relative to 
the second side. The filter, like the rest of the hood enclosure, is 
constructed of an aluminized steel or stainless steel material and 
includes first and second pluralities of individual and parallel extending 
baffle members which are offset relative to one another and which are 
secured within a surrounding frame. Each of the baffle members further 
include in cross section a first leg and a second angularly extending leg 
and, in operation, the filter effectively removes such contaminants as 
airborne grease and other objects from the exhausted air stream. The 
second and lower elongate bracket further includes a trough which collects 
the grease and other contaminants through apertures in the bottom of the 
filter which are then emptied into a removable grease tray which is 
releasably secured to the housing proximate a forward location along the 
second side. 
An elongate and planar shaped deflector extends in proximity to a bottom 
edge of the filter at a further specified angular orientation relative to 
the second side. The deflector functions to cause a further deflected 
stream of exhaust air from the filter, which would otherwise escape from 
the hood enclosure into the room interior, to be redirected towards the 
filter for evacuation from the housing, thus increasing the efficiency of 
the hood.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, an overhead ventilation hood is shown at 10 for 
use within a ventilation system for a conventional cooking appliance 12 
according to the present invention. The types of cooking appliances 12 
with which the hood 10 may be utilized include pizza ovens, other types of 
ranges, fryers and just about any other type of commercial appliance which 
produces a significant level of smoke, heat, airborne grease and odors for 
which it is desired to evacuate from within an enclosed area. 
The ventilation hood 10 is incorporated within an overall ventilation 
system, such system including a first blower (not shown) of conventional 
construction and mounted in communication with a first length of ductwork 
14 (see FIG. 3) extending to the hood 10 at a first location and a second 
blower or exhausting fan (likewise not shown) mounted in communication 
with a second length of ductwork 16 (again see FIG. 3) extending from the 
hood at a second location. The ductwork is typically aluminum, carbon 
steel, stainless steel or other lightweight metal composite suitable for 
use in the industry. The blowers are typically mounted at a rooftop 
location above the room enclosure within which the hood 10 is situated and 
function to introduce a first stream of pressurized intake air 18 through 
the first length of ductwork 14 and to evacuate a second stream of 
pressurized exhaust air 20 through the second length of ductwork 16. As 
will be subsequently described in more detail, the purpose of the intake 
air 18 is to establish an equilibrium state within the hood enclosure so 
the quality air within the room enclosure (heated or air conditioned air) 
is not evacuated with the exhaust air stream 20. The ideal construction of 
the present invention further prevents the unconditioned or unheated 
outside supply air from escaping the hood enclosure and intermixing with 
the quality air within the room. 
Referring again to FIG. 1, the hood 10 is constructed of an aluminized 
steel or stainless steel housing having a planar shaped base 22 which is 
adapted to be secured at an elevated location above the cooking appliance 
12, such as by heavy duty hangers anchored to the ceiling or by other 
conventional securing means. The housing includes a recessed interior 
which is arrayed in a downwardly facing manner and forms a substantially 
rectangular shape which is defined by a first side 24, a second spaced 
apart side 26, a first interconnecting end 28 and a second interconnecting 
end 30. An intake opening 32 is formed through the housing base 22 
proximate the first side 24 and is secured to the first length of ductwork 
14 for receiving the first stream of intake air 18 and a further intake 
opening 34 is formed through the housing base 22 proximate the second side 
26 and is secured to the second length of ductwork 16 for receiving the 
second stream of exhaust air 20. 
A supply plenum chamber is established within the recessed interior of the 
housing an along the first side 24 and includes a first elongate and 
planar shaped channeling wall 36 extending in an inwardly and downwardly 
angled direction towards the first side 24 and a second elongate and 
planar shaped channeling wall 38 extending from the first side 24 in an 
upwardly and outwardly angled direction. According to the preferred 
embodiment, the first channeling wall 36 extends at a 30 degree angle 
relative to the first side 24 (see at 40 in FIG. 3) and the second 
channeling wall 38 extends at a further 75 degree angle relative to the 
first side 24 (see at 42). 
An elongate and planar shaped diffuser 44 is secured at opposite ends 
thereof to the exposed ends of the first and second planar shaped 
channeling walls 36 and 38 (such as by welding or the like) and, along 
with the first and second planar shaped channeling walls, extend the 
distance between the first and second interconnecting ends 28 and 30 so as 
to enclose the space defined by the supply plenum chamber. As best viewed 
in cross section, the diffuser 44 extends in a reverse angular fashion 
relative to the first and second planar shaped channeling walls 36 and 38 
and so that it adopts a slight inward and angular configuration 46 
(preferably in the range of 10 to 20 degrees) relative to a vertical axis 
parallel to the first wall 24. Depending upon the specified width 
configuration of the channeling walls 36 and 38, as will be further 
discussed, the angular range of the diffuser 44 may be further modified to 
suit a particular application. 
The diffuser 44, similar to the channeling walls 36 and 38, is constructed 
of an aluminized steel or stainless steel material and includes a planar 
face within which are formed a plurality of individual apertures. As best 
shown in FIG. 4, the apertures 47 are preferably oblong holes which run 
the full length of the diffuser (preferably less 12 inches at each end) 
and the full height so as to define a pass-through location for permitting 
the intake air stream to flow therethrough in a desired regulating 
fashion. The individual apertures 47 formed by the oblong holes in the 
diffuser 44 preferably consist of between 50% and 75% or more of the open 
area defined by the planar face of the diffuser and the quantity and 
placement of the apertures is determined so as to provide for a desired 
level of regulated flow through the supply plenum chamber and into the 
hood enclosure. As best shown in FIG. 3, the intake stream 18 is 
illustrated passing through the supply plenum chamber and into a central 
open interior of the housing. As is also shown at 48, 50 and 52, layers of 
insulation (preferably an inch thick) are layered over the first 
channeling wall 36, second channeling wall 38 and first extending side 24, 
respectively, and the insulation assists in provides a barrier to 
temperature variation between the supply air flow 18 prior to it being 
introduced to the hood enclosure interior. 
An elongate and arcuate shaped air flow distribution element 54 is secured 
upon the second channeling wall 38 and extending in a longitudinal 
direction towards the opposite and first and second extending and 
interconnecting ends 28 and 30. As is best shown in FIG. 4, the arcuate 
shaped distribution element 54 has flattened upper and lower surfaces and 
forms a continuous curved shape which functions to cause the first stream 
of intake air 18 to be equally distributed along the supply plenum chamber 
between the first and second interconnecting ends and so as to further 
provide for even regulated flow through the diffuser element 44. 
Referring again to FIG. 3, an exhaust plenum chamber is established within 
the interior of the hood enclosure and along the second extending side 26. 
The exhaust chamber is defined in large part by an elongate and planar 
shaped filter 56 which extends between the first and second 
interconnecting sides 28 and 30 and which is secured to the housing 
interior by a first upper and elongate bracket 58 and a second lower, 
spaced apart and opposingly facing, bracket 60. The first bracket 58 
defines a first inwardly facing channel 62 and the second bracket 60 
substantially defines a second inwardly facing channel 63 for receiving 
opposite engaging ends of the filter 56. 
As is further best illustrated in the sectioned view of FIG. 5, the filter 
56 is constructed of an aluminum or stainless steel material and 
particularly includes an encircling frame 64 which secures and supports a 
first plurality of individual and parallel extending baffle members 66 and 
a second spaced apart plurality of individual and parallel extending 
baffle members 68. The pluralities of baffle members 66 and 68 may be 
secured to the frame 64 by welding or other conventional attachment means 
as are known in the art and each individual baffle member 66 and 68 
includes in cross section a first leg and a second angularly extending leg 
as is clearly illustrated. The purpose of the baffle members is to provide 
a circuitous path for the exhaust stream 20 as it passes through to the 
exhaust plenum chamber and out through the second length of ductwork 34 to 
facilitate the collection of airborne particles from the exhaust stream, 
such typically including airborne grease and other contaminants. For this 
purpose, the bottom of the frame 64 may be open in whole or in part (see 
at 70) to facilitate the pass through of the grease through the bottom of 
the filter 56 and an explanation of the ability to collect and reposit the 
airborne contaminants will be described below. 
Referring again to FIG. 3, the filter 56 is illustrated in a releasably 
mounted fashion within the hood enclosure interior in an upwardly and 
outwardly extending and specified angular orientation 72 relative to a 
vertical axis extending through the second side 26. Preferably the filter 
56 extends at a thirty degree orientation relative to the vertical and 
encloses a substantially triangular shaped area which defines the exhaust 
plenum chamber. The second and lower extending bracket 60 further defines, 
beneath the second inwardly facing channel 63 for receiving the bottom 
locating edge of the filter 56, a lower collection trough 74 which is 
capable of collecting the airborne grease and other contaminates from the 
stream of exhaust air (via the filter 56). As is illustrated in FIG. 1, 
the lower bracket 60 with collection trough 74 preferably is angled to a 
minor degree off the horizontal axis, as shown at 76, towards a forward 
end of the second side 26 and in proximity to the first interconnecting 
end 28. Referring back to FIG. 3, a grease collection tray 78 is 
releasably secured to the housing proximate the forward and 
interconnecting location of the second side 26 with the first 
interconnecting end 28 and beneath a communicating opening 80 in the 
trough 74 (and which represents the lowermost position of the trough) for 
collecting the grease captured by the filter 56. 
As is best shown in FIG. 3, an elongate and planar shaped deflector 82 
extends in proximity to a bottom edge of the filter 56 and, according to 
the preferred embodiment, is secured to the second and lower extending 
bracket 60 and is removable for cleaning. The deflector 82 extends 
substantially the length of the exhaust plenum chamber but is of a much 
smaller width as opposed to the filter 56. The deflector 82 extends at a 
further specified angular orientation relative to a vertical plane, as 
illustrated by directional arrow 85, and in the preferred embodiment 
extends at a forty-five degree angle relative to the vertical plane 
defined by the second side 26 of the housing. 
The purpose of the deflector 82 is to capture a deflected portion 84 of an 
exhaust stream 86 from the filter 56 surface before the deflected portion 
84 of the stream has an opportunity to escape from the hood enclosure and 
to redirect the deflected portion 84 back through the filter 56 for more 
complete exhausting of the heat, smoke, airborne grease, odors and other 
undesirable by-products of the cooking device (as illustrated by the 
directional arrows 88 in FIG. 1) and for which it is desirable to evacuate 
from the room enclosure. A light fixture 90 may also be secured at a 
generally centralized location to the base surface 22 of the hood 
enclosure to provide a desired degree of illumination within the enclosure 
interior. 
In specific preferred embodiments, the overall dimensions of the 
rectangular hood enclosure include the first and second sides, the 
diffuser and channeling walls, the filter element, and the deflector 
(which form portions of the supply plenum and exhaust plenum chambers), 
and the interconnecting ends being established at such lengths as 7'6", 
9'0" and 10'0" to accommodate cooking devices, and particularly pizza 
ovens, of differing dimensions. It is further envisioned that any hood 
length between 4'0" and 16'0" may be employed according to the present 
invention. The overall depth of the sides and interconnecting ends may 
also vary, but a standard 2.0 feet has been found to be sufficient for 
accomplishing the necessary air mixing, filtration and removal according 
to the objectives of the present invention for evacuating the by-products 
of the cooking process with minimal disturbance to the internal equality 
condition of the air in the room enclosure. Additionally, trim panels (see 
96) may be installed through the provision of J-hooks 92 and 94 (with 
additional hooks not shown for the first and second ends). The hooks 92 
and 94 support corresponding bottom edges of the decorative panels for 
ease of installation. Upper ends of the trim panels are further secured 
against the exterior faces of the sides and ends of the hood by any 
conventional means known in the art. 
Having described our invention, it will become apparent that it discloses a 
novel and improved hood for use within a ventilation system which is an 
improvement over the prior art devices. Additional embodiments will become 
apparent to those skilled in the art to which it pertains without 
deviating from the scope of the appended claims.