Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF INVENTION
This invention relates to a moveable, self-contained
exhaust unit for recirculating exhaust air from elec~rical
cooking apparatus, and particularly relates to an exhaust unit
~hich obviates the need of separate ductwork.
BACKGROUND TO THE INYENTION
Various apparatus for ventilating or exhausting fumes
from a stove have heretofore been devised.
For example, United States Patent No. 4,350,504
discloses a cooking unit having a hood equipped with air cleaning
structure and blowers for moving air through the cleaning
structures, and in particular clean air is discharged laterally
off the hood into the environment surrounding the cooking
equipment through various outlets.
Furthermore, United States Patent No. 4,047,519
discloses an exhaust hood apparatus which is adapted to be
installed in the area above a stove or grille in a kitchen.
Moreover, United States Patent No. 4,043,320 relates to
a hood assembly for removing grease from vapours generated by
griddles and other types of range units.
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United States Patent No. 3,303,839 relates to a
ventilated cook stove unit which is adapted to be moved from
place to place.
Finally United States Patent No. 3,334,621 teaches a
cooking appliance hav;ng a hor;zontal a;r d;scharge duct
positioned between the cooking platform and a base support
assembly. Air discharging from the duct is directed in a
horizontal path by a grille disposed in the exhaust end of the
duct. A pair of air deflectors co-operate with the grille and
each deflector has a plurality of vertical vanes interposed
between the grille and duct.
Each of the prior art devices referred to above present
relatively complicated structure having limited use as the
ventilation system may either be constructed as a part of the
cooking apparatus and therefore may only be used with such
cooking apparatus or else are adapted to be connected to air
ducts or the like in order to properly ventilate the exhaust air.
It is an object of this invention to provide a
ventilation system which is adapted to receive and vent the
exhaust air from a variety of electrical cooking units and which
obviates the need of air ducts.
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SUMM~RY OF ~HE INVEN~ION
The broadest aspect of this invention relates to a moveable
self-contained exhaust unit for filtering exhaust air from
cooking apparatus comprising: a housing having a passage defined
by a first chamber and a second chamber communicating with said
first chamber said first chamber disposed laterally adjacent said
second chamber; an air inlet communicating with said first
chamber; an air outlet communicating with said second chamber:
a hood assembly having a top wall presenting two ends and two
side walls depending from the ends of said top wall, said top and
side walls connected to said housing so as to define an enclosure
having an opening for removably receiving said cooking apparatus
within said enclosure, said hood assembly including aperture
communicating with said air inlet of said housing; removable
filter disposed interiorally of said housing in said first
chamber; blower associated with said passage for drawing said
exhaust air from said cooking apparatus through said aperture,
said air inlet into said first chamber and through said filter
to filter said exhaust air and for exhausting said filtered air
through said second chamber and said air outlet to the exterior
of said unit.
Another aspect of this invention relates to a moveable self-
contained exhaust unit for filtering exhaust air from cooking
apparatus and discharging filtered exhaust air exteriorally of
said unit comprising: a generally rectangular housing having a
passage defined by a first chamber and a second chamber
communicating with said first chamber said first chamber disposed
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late:rally adjacent said second chamber; an air inlet
communicating with said first chamber; an air outlet
communicating with said second chamber; a hood assembly having
a top wall presenting two ends and two spaced side walls
depending from the ends of said top wall, said top and side walls
connected to said housing so as to define an enclosure having an
opening thereto for removably receiving said cooking apparatus
within said enelosure, said housing including aperture
communicating with said air inlet of said housing; grease filter
disposed over said aperture of said hood; removable air filter
located within said first chamber of said air passage; odor
control associated with said first chamber of said air passage
for controlling the odor of air filtered through said air
filtering; blower associated with said passage for drawing
exhaust air from said electrical cooking apparatus through said
aperture, said air inlet, said filter in said first chamber to
filter said exhaust air and to discharge said filtered exhaust
air through said second chamber and said air outlet to the
exterior of said unit.
Yet another aspect of this invention relates to a moveable
self-contained exhaust unit for drawing exhaust air from cooking
apparatus into said unit and discharging filtered exhaust air
exteriorally of said unit comprising: a generally rectangular
housing having an upper wall, lower wall, front wall, back wall,
and two side walls; a passage defined by a first chamber and a
second chamber communicating with said first chamber; an air
inlet communicating with said first chamber; an air outlet
located in said upper wall and communicating with said second
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chamber; a hood assembly havin~ a top wall and two side walls
depending from said ends of said top wall, said top and side
walls connected to said upper and side walls of said housing so
as to define an enclosure having an opening for removably
receiving said cooking apparatus within said enclosure, said hood
assembly including aperture communicating with said air inlet of
said housing; filter disposed interiorally of said housing in
said first chamber; blower disposed interiorally of said housing
and located at said lower wall for drawing said exhaust air from
said cooking apparatus through said aperture, said air inlet and
through said first chamber and said filter to filter said exhaust
air and discharge said filtered exhaust air through said second
chamber to said air outlet to the exterior of said unit.-
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DRAWINGS
These and other objects and features shall now be
described in relation to the following drawings:
Figure 1 is a front perspective view of said moveable self-
contained exhaust unit.
Figure 2 is a rear elevational view of said moveable self-
contained exhaust unit.
Figure 3 is a side elevational view of said moveable self-
contained exhaust unit taken along the lines 3-3 of Figure 2.
Figure 4 is a side elevational view of said moveable self-
contained exhaust unit taken along the lines 4-4 of Figure 2.
Figure 5 is a side elevational view of said moveable self-
contained exhaust unit taken along the lines 5-5 of Figure 2.
Figure 6 is a top plan view of said unit.
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Figure 7 is a rear elevational view of said exhaust unit.
Figure 8 is a front elevational view of said exhaust unit.
Figure 9 is a view of the fire protection system.
Figure 10 is a wiring diagram of the exhaust unit.
DESCRIPTION,OF THE INVENTION
Like parts will be given identical numbers throughout
the figures.
The exhaust unit is generally depicted by numeral 10
and comprises a body 12 and a hood assembly 14 which is connected
to the body 12.
The exhaust unit 10 is adapted to receive electrical
cooking equipment within the confines of the hood 14. Although
two electrical fryers 16 and 18, and one electrical griddle 20 is
disclosed in Figure 1, other arrangements of electrical cooking
apparatus may be accommodated by the exhaust unit 10.
The exhaust unit 10 illustrated herein is moveable to
any location and is particularly well adapted for servicing fast
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food outlets in shopping centres or the like where electrical
cooking appliances are utilized, as the exhaust unit 10 depicted
herein is a self-contained unit obviating the need to be
connected to expensive ductwork. The exhaust unit 10 is moveable
by providing removable castors at the bottom of the unit. Once
the unit 10 is moveable along the castors to the devised location
the castors may then be removed so as to fixedly locate the unit
10 in the devised location due to the weight of the unit 10.
More particularly, the exhaust unit 10 disclosed herein
recirculates or vents clean air into the environment surrounding
the exhaust unit 10 thereby making it unnecessary to instal
expensive ductwork to vent the cleaned air outside of the
shopping mall or the like.
The body 12 comprised spaced top and bottom walls 22
and 24 respectively joined to sidewalls 26 and 28 and front and
back walls 30 and 32 respectively.
The body 12 and in particular walls 22, 24, 26, 28, 30
and 32 are manufactured from stainless steel 18 gauge cold rolled
steel.
The hood assembly 14 includes a top portion 34 which is
connected to the top wall 22 of body 12 so as to define a common
plane.
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The hood assembly 14 also includes side portions 36 and
38 which are jointed to the sidewalls 26 and ~8 of body 12 so as
to define common planes respectively. The hood assembly 14 and
particularly the portions 34, 36 and 38 are manufactured from
stainless steel 18 gauge cold rolled steel.
The interior of the body 12 is best illustrated in Figures 2, 3
and 4. The body or housing 12 includes an air passageway 40 defined ~y a
first chamber 33 and a second chamber 35 communicating with the first chamber.
10 Said first chamber disposed laterally adjacent said second chamber. More
particularly, the first chamber is best illustrated in Figure 2 and comprise
the region whereby the Arrows A pointed upwardly. The air inlet 42
communicates with the first chamber of passageway 40 and the air outlet
communicates with the second chamber of passageway 40.
The hood assembly 14 includes an aperture 46 which
communicates with air inlet 42 of body 12. The hood assembly 14
also includes grease filter 48 which is disposed over aperture 46
and is adapted to remove grease and other large particles which
20 are carried away by the exhaust air from the cooking surface of
cooking appliances 16, 18 and 20.
A blower assembly generally depicted by numeral 47 is
located internally of body 12 and is adapted to draw exhaust air
from the cooking surface through grease filter 48, through
aperture 46, through air inlet 42, through passage 40, and out
air outlet 44.
The blower assembly 47 comprises a motor 50, fan shaft
30 and bearing 52 and fan wheel 54.
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The body 12 also includes filter assembly material
generally depicted by 56 for filtering exhaust air drawn through
the passage 40 by blower 48. The filter material 54 may comprise
of a variety of materials well known to those persons skilled in
the art.
More particularly filter assembly 56 contains three
stages namely, a pre-filter 58 which is 30~ A.S.H.R.A.E. rated, a
medium filter 60 which is 90% A.S.H.R.A.E. rated~ and an absolute
filter 61 which is 99% A.S.H.R.A.E. rated.
A filter fire damper 64 is installed in the passageway
40 upstream of the blower assembly 47 and contains a 286
fahrenheit fusible link. In other words, once the temperature of
the air and passageway 40 reaches 286 fahrenheit, the fusible
link is adapted to melt, thereby shutting off the passageway 40
so that blower assembly 47 does not blow or distribute air
through air outlet 44 for safety reasons.
The unit 10 also includes an ecology controlled unit 66
or an odour control unit which is adapted to spray chemicals into
the ~iltered air in a manner well known to those persons skilled
in the art in order to control the odour of the filtered air
circulated through the air outlet 44.
Furthermore, the hood 14 includes a seriès of fire
suppression liquid distribution and detection line 68 which are
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connected to a fire suppression tank 70 located within body 12.
In particular the fire suppression tank 70 includes a wet
chemical which is adapted to flow through the line 68 in the
event of a fire in the vicinity of the cooking apparatus 16, 18
or 20, aperture 46 and air passage 40. Figure 9 more fully
illustrates the fire prOteCtiQn system which includes plenum
nozzles 86 which are adapted to spray a wet chemical within the
confines of the hood 14, and appliance nozzles 84 which are
adapted to spray wet chemical onto the appliances 16, 18 and 20.
10 Heat detectors 88 are provided which are adapted to provide a
signal to the fire switch control box 82 in the event of sensing
an elevated temperature. The control box 82 then activates tank
70 to spray wet chemical as described above. A pull station 80 is
also provided to manually activate tank 70.
The unit 10 also includes a central panel which
includes a series of electrical controlled units for controlling
the operation of the unit 10. In particular, the control panel
includes circultry to turn the blower assembly 47 on and off and
20 is electrically wired to a series of limit switches 74, one for
each filter 58, 60 and 61, which switches are adapted to monitor
the air resistance across each said filter so as to activate an
alarm and pilot light when the resistant reaches a predetermined
setting.
Such pressure switches 74 are also adapted to detect a
drop in air resistance in the event that a filter 58, 60, or 61
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is removed and not replaced; in which event the pressure switch
74 will stop the blower assembly 47 and activate the alarm and
pilot light (not shown).
The mai n control panel 72 al so i ncl udes a mai n
disconnect, fuse block, motor starter and thermal overload, pilot
lights~ alarm, transformer and on/off push buttons. Such control
panel 72 is wired so that if any control is activated to stop the
blower assembly 47 the power supply to the cooking appliances 16,
10 18 or 20 will be turned off. The control panel 72 will be wired
to a firestat adapted to stop the blower assembly 47 at 350
fahrenheit air temperature.
Figure 7 illustrates access door 94 which provides an
access to the filter assembly 56 for removing and changing same;
as well as an access door 96 for entry into the motor 50. An
acoustic noise silencer 45 is also provided.
Figure 8 illustrates the provision of a grease cup 90
20 for collecting grease running off the grease filters 48.
Appliance receptacles 92 are also provided for providing
electrical power to the appliances 16, 18 and 20. An appliance
contactor 51 and appliance circuit breaker 53 is also included as
illustrated in Figure 3.
In summary the operation of the unit 10 is adapted to
clean kitchen exhaust air, remove grease, smoke and other
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contaminants, and the clean air is adapted to be recirculated
into the building where there is a higher rate of air change
required for ventilation.
It is applicant's understanding that the minimum fresh
air supply in shopping centre malls is in the ~icinity of 0.15
cubic feet per minute (C.F.M.) per square foot of floor area and
an average total air supply of 1.25 C.F.M. per square foot.
The following is an example of the minimum floor space
required to operate the unit 10 for a unit 6 feet long which is
adapted to operate at 300 C.F.M. per foot. Accordingly, the air
flow through the unit would equal 6 x 300 or 1,800 C.F.M. exhaust
air.
If we allow for 2 minute air changes which require
1,-800 divided by 2 or 900 C.F.M. minimum of fresh outside air.
Therefore the floor area required at 0.15 C.F.M. of outside air
per square foot would equal 900 divided by 0.15 or 6,000 square
feet of area.
It should also be noted that the average temperature
for a mall supply air unit is in the vicinity of 55 fahrenheit.
As the outside air temperature decreases the percentage of
outside air required also decreases. For example, if we assume
the following:
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(a) 80 fahrenheit return air temperature for mall air
conditioning system;
(b~ 55 fahrenheit supply air temperature for mall air
conditioning system; and
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(c) 30 fahrenheit outside air temperature which is the average
winter outside temperature
the following calculation may be made:
(50% mall return air @ 80) + (50% fresh air @ 30
divided by 100% = 55 fahrenheit
This indicates that at 30 fahrenheit outside air
temperature the total supply alr would be made up of 50% fresh
air.
By using the 6,000 square foot figure referred to
earlier and 1.25 C.F.M. per square foot, the total air would be
6,000 x 1.25 or 7,500 C.F.M.
Therefore with a 30 fahrenheit outslde temperature the
fresh air required would be 50% of 7,500 or 3,750 C.F.M. This
would give an air change for the clean exhaust air of 3,750
divided by l,B00 or .48 minutes.
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Figure 10 shows the wiring diagram of the exhaust unit.
The top of the unit 10 is provided with an aperture 27 as
illustrated in Figure 6 for receiving the electrical wires.
Although the preferred embodiment as well as the
operation and use have been specifically described in relation to
the drawings, it should be understood that variations in the
preferred embodiment could be achie~ed by a man skilled in the
art without departing from the spirit of the invention.
Accordingly, the invention should not be understood to be limited
to the exact form revealed by the drawings.
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