U.S. patent number 3,859,901 [Application Number 05/445,449] was granted by the patent office on 1975-01-14 for recirculating ventilating hood.
This patent grant is currently assigned to General Electric Company. Invention is credited to James A. White.
United States Patent |
3,859,901 |
White |
January 14, 1975 |
RECIRCULATING VENTILATING HOOD
Abstract
A baking and broiling oven is provided with a recirculating
ventilating hood having a spring-mounted motor-blower unit. A thin,
flat filter box of large area is attached to the underside of the
motor-blower unit and carried thereby so as to have a low noise
level and high air flow at relatively slow speeds; hence, high
efficiency of air filtration.
Inventors: |
White; James A. (Louisville,
KY) |
Assignee: |
General Electric Company
(Louisville, KY)
|
Family
ID: |
23768939 |
Appl.
No.: |
05/445,449 |
Filed: |
February 25, 1974 |
Current U.S.
Class: |
126/299R;
126/273A |
Current CPC
Class: |
F24C
15/2042 (20130101) |
Current International
Class: |
F24C
15/20 (20060101); F24c 015/20 () |
Field of
Search: |
;126/21R,21A,273A,299B
;98/115K,115R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Favors; Edward G.
Claims
I claim:
1. A recirculating ventilating hood for installation on the top of
an oven, said hood comprising a hollow housing with at least a top
wall, a rear wall, opposite side walls, and a front wall having an
air inlet opening, first filter means in said inlet opening, a
spring-mounted motor-blower unit suspended from the top wall of the
housing and exhausting through a clean air outlet in the said front
wall, and a large filter box attached to the underside of the
motor-blower unit and carried thereby, said filter box having a
thin, flat shell of large area with a top wall, a rear wall, widely
spaced opposite side walls, and a front wall that is open along its
bottom portion, and an enlarged opening in the top wall of the
shell, shelf means within the filter box shell at both sides of the
said opening for supporting a second filter means in the bottom
portion of the filter box shell, whereby the large area of the
second filter means allows for a large volume of air flow at a
relatively slow speed and a low noise level and relatively low
motor and filter means temperatures.
2. A recirculating ventilating hood as recited in claim 1 wherein
the said filter box shell includes a center brace located beneath
and spaced from the said opening and connected to both the front
wall and rear wall of the shell, said center brace serving as part
of the said shelf means for supporting the second filter means.
3. A recirculating ventilating hood as recited in claim 2 wherein
when the motor-blower unit is energized, an air flow is set up so
that the air enters through the air inlet opening in the front wall
of the hood housing and passes through the first filter means, then
spreads out beneath the entire filter box and rises up through the
second filter means and accumulates near the said opening and
passes therethrough and into the blower and finally out the clean
air outlet.
4. A recirculating ventilating hood as recited in claim 1 wherein
the said front wall of the hood housing is removable from the front
so that the said second filter means may be disengaged from the
filter box and removed easily through the front of the housing for
cleaning and replacement.
5. A recirculating ventilating hood as recited in claim 1 wherein
the motor-blower unit has a scroll-shaped housing enclosing a
single blower wheel and supporting a drive motor having a vertical
shaft that is connected to the blower wheel, the said motor
extending down beneath the blower housing and into the said top
opening in the filter box.
Description
BACKGROUND OF THE INVENTION
Ventilating hoods are commonly installed over kitchen ranges and
cooktops or assembled directly on built-in wall ovens or eye-level
ovens of free-standing ranges. In all instances they handle grease,
odors and vapor-laden hot air formed during various cooking
operations so that the air should first be filtered before reaching
the motor-blower unit and being vented to the outside of the
kitchen or returned to the kitchen in a recirculating manner.
The present invention relates to a recirculating ventilating hood
which is not vented to the outside of the kitchen, but instead
returns the filtered air to the kitchen atmosphere. The majority of
kitchen ventilating hoods are vented to the outside and this
disposes of the filtered air. One disadvantage of a vented hood is
that it usually requires special carpentry work and sheet metal
duct work to carry the exhaust air to the outside of the kitchen;
hence, vented hoods add additional cost to the installation of the
kitchen range or oven. Another disadvantage is that sometimes the
location of the range or oven is such that it is not feasible to
install a vent duct through the wall or through the ceiling of the
kitchen. Such vented hoods are taught in the three related patents
of Donald L. Cole, U.S. Pat. Nos. 3,292,523, 3,292,524, and
3,327,610, all of which are assigned to the assignee of the present
invention.
One known manner of converting a vented hood to a recirculating
hood is to install a filter box on the top of the vented hood,
which filter box is downstream of the motor-blower unit, and then
returning to the filtered air to the kitchen atmosphere. This is
taught in the Bandlow U.S. Pat. No. 3,075,335.
The principal object of the present invention is to provide a
kitchen ventilating hood with a large recirculating filter box that
is installed within the hood housing and suspended below the
motor-blower unit so as to cut down on the noise level of the hood
assembly.
A further object of the present invention is to provide a
recirculating ventilating hood with a filter box construction of
the largest possible size that takes up the least space within the
hood housing so as to have a large volume air flow at a relatively
low velocity, as well as low operating temperatures for both the
motor and the filter mediums.
SUMMARY OF THE INVENTION
The present invention, in accordance with one form thereof, relates
to a recirculating ventilating hood that is adapted to be mounted
directly on the top of an oven. The hood includes a spring-mounted
motor-blower unit suspended from the top portion of the hood
housing, and there is a large filter box attached to the underside
of the motor-blower unit and carried thereby. A front wall of the
hood housing includes an air inlet opening and a clean air outlet
opening. Filter means are installed in the filter box so as to
handle a large volume of air at a relatively low velocity and at a
relatively low noise level and at low operating temperatures of the
filter medium as well as of the motor for ease in service and
improved efficiency without any increase in the overall size of the
hood housing.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention will be better understood from the following
description taken in conjunction with the accompanying drawings and
its scope will be pointed out in the appended claims.
FIG. 1 is a fragmentary perspective view of an eye-level oven of an
electric range (not shown) with a recirculating ventilating hood
according to the present invention, mounted directly on the top of
the oven.
FIG. 2 is a fragmentary cross-sectional, side elevational view on
an enlarged scale taken generally through the center of the hood
and the center of the motor-blower unit.
FIG. 3 is an exploded view of several of the main components of the
present invention; for example, the filter box and its various
large filters. The filter box is to be fastened to the underside of
the motor-blower unit and carried thereby.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to a consideration of the drawings, and in particular
to FIG. 1, there is shown an eye-level, electric oven 10 which is
of the type found in a double oven range where the eye-level oven
is mounted above a cooktop and there is a second oven located
beneath the cooktop. The lower portion of such a range is not
illustrated here as it is somewhat standard in the range art. This
same oven 10 could be a built-in wall oven. This oven is generally
of standard construction having a cooking cavity 12, as best seen
in FIG. 2, formed by a box-like oven liner 14 and a front-opening
access door 16. A blanket of thermal insulation 18, such as fiber
glass or the like, surrounds the oven liner for retaining as much
of the oven heat as possible within the cooking cavity. The oven
door 16 is provided with a viewing window 20 of multiple panes, and
this door is also provided with insulation so as to form a thermal
barrier for retaining the oven heat. A control panel 22 is located
at one side of the oven door 16, and it may contain control
components, such as an oven timer, an oven thermostat, and an oven
selector switch, as is conventional in this art.
The present invention relates to a recirculating ventilating hood
25 which is shown mounted directly on the top of the oven 10. The
hood 25 has a hollow box-like housing 27 of sheet metal
construction having the same dimensions in plan view as the top of
the oven so that the hood 25 in effect represents a vertical
extension of the oven 10. The hood housing 27 has a top wall 29, a
rear wall 31, opposite side walls 33 and a front wall 35 with an
air inlet opening 37 adjacent the bottom portion of the front wall.
The front wall 35 has a rearwardly extending barrier 36 that
cooperates with a motor-blower unit 49. The control switch for the
hood is not shown but it would be mounted in the front wall 35 of
the hood. A grease filter 39, of aluminum mesh or the like, is
assembled over the air inlet opening 37. This grease filter 39 is
shown to be taller than the height of the air inlet opening 37.
This is due to a parts standardization program. This same grease
filter 39 is used in the production model of our vented hood, and
we use the same filter in our recirculating hood in order to hold
down the number of different parts in our inventory. It will be
understood that only the lower part of the filter 39 which overlies
the air inlet opening 37 is effective to filter the air. The upper
portion of the filter 39 is ineffective because it bears against
the front wall 35 for at least the upper half of the filter. This
filter 39 may be inserted at intervals so as to gain full use of
the filter medium. This same grease filter 39 may be seen used for
the air inlet opening in the three Cole patents which were cited
above as part of the prior art. The oven 10 is vented by having an
air gap 41 formed between the top of the oven door 16 and the front
flange 43 of the top wall of the oven liner 14. This air gap 41 is
always open, such that during both baking and broiling operations
oven air is allowed to exhaust upwardly through the air gap 41 to
an area just in front of the filter 39 and the air inlet opening 37
of the ventilating hood 25. A hinged canopy 45 is assembled over
the front wall 35 of the hood housing 27, and it is shown in its
closed position in FIG. 2, and in its open position in FIG. 1. This
canopy would be moved to its open position during the operation of
the motor-blower unit of the hood.
Within the hood housing 27 is mounted a motor-blower unit 49 which
has a scroll-shaped housing 51, as is best seen in FIG. 3, with an
exhaust opening 53. The bottom wall of the scroll housing 51, as
seen in FIG. 2, is provided with a circular opening 55 in which is
mounted a drive motor 57 by means of a series of four motor straps
59. These motor straps are radially spaced around the motor and
attached to the innermost end of the motor by means of bolt
fasteners 61. The opposite ends of the motor straps 59 are welded
as at 63 to the edge of the opening 55 in the bottom wall of the
scroll housing. This drive motor 57 has a vertical shaft 65 on
which is mounted a blower wheel 67 having a plurality of vertical
vanes 69.
This motor-blower unit 49 is connected to the underside of the top
wall 29 of the hood housing 27 by a spring mounting means that is
taught in the Cole U.S. Pat. No. 3,327,610. As seen in FIG. 3, a
hanger bar 71 is attached to the top wall of the scroll housing 51,
and it overhangs the opposite sides of the scroll housing. This
hanger bar 71 is of hat-shaped, transverse cross-section.
Cooperating with this hanger bar 71 is a stationary supporting bar
73, as seen in FIG. 2, which is shown of generally the same
hat-shaped, transverse cross-section as for the hanger bar, and
extending for substantially the same distance as the length of the
hanger bar. This supporting bar is turned face up and preferably
welded to the underside of the top wall of the hood housing 27.
Connections must be provided between the hanger bar 71 and the
overlying supporting bar 73, and this is afforded by a pair of
shouldered bolts 75, one at each end of the hanger bar 71, which
may be quickly connected and disconnected from the supporting bar
through suitable slot means in the front of the supporting bar, as
is best explained in the aforementioned Cole U.S. Pat. No.
3,327,610. The mid-section of each bolt 75 is surrounded by a
coiled spring 77 on which the hanger bar 71 is supported to give a
spring support for the motor-blower unit 49.
It is desirable that the motor-blower unit 49 be easily removable
from the hood housing 27 by first removing the canopy 45 in the
front wall 35 of the housing by removing the fastening screws 80
that attach the front wall in place. Then by grasping the two
hanger bolts 75 they may be released from the supporting bar 73 and
the entire motor-blower assembly may slowly be withdrawn from the
hood housing 27.
In order to have a satisfactory recirculating ventilating hood it
is necessary to have suitable filter mediums to remove the grease,
smoke, odors and vapors from the air before it reaches the motor
and blower and before the air is returned to the kitchen
atmosphere. Preferably, such filter mediums are installed upstream
of the blower system so as to protect the motor and blower from the
air pollutants.
The present invention incorporates a thin, flat filter box 85 of
large expanse, as is best seen in FIG. 3, that is attached to the
underside of the motor-blower unit 49 and carried thereby so that
the filter box is also spring mounted through the motor-blower
unit, thereby being isolated from the hood housing and reducing the
noise level of the entire assembly. The nature of the filter box 85
can be best understood from the exploded perspective view of FIG.
3. The filter box 85 has a thin, flat shell of large planar area
that is almost as wide as the hood housing 27. It has a top wall
87, a rear wall 89, widely spaced opposite side walls 91, a front
wall 93 that is open along its bottom portion, and finally it has
an open bottom wall. An enlarged motor-receiving opening 95 is
formed in the top wall 87 of the filter box shell substantially in
the center thereof, and it has an inwardly tapered collar 97 which
is adapted to telescope within the inlet opening 55 of the bottom
wall of the motor-blower scroll housing 51. Screw openings 98 are
formed in the top wall 87 of the filter box for receiving screws
(not shown) that are threaded into suitable openings in the bottom
wall of the scroll housing 51.
A center brace 99 is located beneath and spaced from the
motor-receiving opening 95 and this brace is of wide channel-like
form that extends from front to back of the filter box shell. This
brace 99 is attached to the underside 100 of the front wall 93 of
the shell, as by screw fasteners or the like. The rear wall 89 of
the shell has a forwardly turned flange 101 along its bottom edge
on which the center brace 99 is seated and fastened as by screw
fasteners or the like. Thus, the center brace serves to reinforce
the filter box shell and restrict any noise generations due to
vibrations set up by the operation of the motor-blower unit. Notice
the center brace 99 also has a circular opening 102 for receiving
the motor 57 therein.
The preferred embodiment of the present invention has the filter
box 85 provided with two pairs of filter mediums, the bottom filter
103 of each pair being a grease filter of fiber glass or the like
that also removes smoke particles. There is also a top filter 105
in each pair of filters of activated coconut shell or pecan shell
charcoal or the like for absorbing odors and other pollutants.
These two pairs of filters 103 and 105 are adapted to be installed
in the bottom portion of the filter box 85. Their support is
afforded by an inwardly turned flange 107 formed on the bottom edge
of each side wall 91, and by an oppositely facing flange 109 formed
along the bottom edge of the side of the center brace 99. These two
flanges 107 and 109 form rails on which the double filters 103 and
105 are capable of sliding into the filter box beneath the front
wall 93 of the filter box shell.
It will be understood from FIG. 2, that the air exits from the oven
through the air gap 41 along the top edge of the oven door and
across the front of the ventilating hood 25 and through the first
grease filter 39 and through the air inlet opening 37 from which it
spreads out beneath the entire filter box 85. Due to the suction
created by the blower wheel 67 the air is drawn upwardly through
the two pairs of filters 103 and 105 into the upper portion of the
filter box shell. Then the air is drawn together towards the
motor-receiving opening 95 and passes up around the motor 57 and
into the blower wheel 67 from which it exits through the exhaust
opening 53 of the scroll housing. The upper portion of the front
wall 35 of the hood housing has an elongated clean air outlet 115
such that the clean air discharges back into the kitchen at an
upward angle so as not to prove uncomfortable to a person standing
in front of the oven.
Modifications of this invention will occur to those skilled in this
art, therefore it is to be understood that this invention is not
limited to the particular embodiments disclosed but that it is
intended to cover all modifications which are within the true
spirit and scope of this invention as claimed.
* * * * *