U.S. patent number 3,732,802 [Application Number 05/125,750] was granted by the patent office on 1973-05-15 for ventilating hood and blower device therefor.
This patent grant is currently assigned to Caloric Corporation. Invention is credited to Dezso S. Kristof.
United States Patent |
3,732,802 |
Kristof |
May 15, 1973 |
VENTILATING HOOD AND BLOWER DEVICE THEREFOR
Abstract
A kitchen ventilating hood for handling the forced circulation
of air and more particularly a motor-blower unit therefor wherein
means is provided for cooling the motor.
Inventors: |
Kristof; Dezso S. (Orefield,
PA) |
Assignee: |
Caloric Corporation (Topton,
PA)
|
Family
ID: |
22421235 |
Appl.
No.: |
05/125,750 |
Filed: |
March 18, 1971 |
Current U.S.
Class: |
126/299D;
310/62 |
Current CPC
Class: |
F24C
15/20 (20130101) |
Current International
Class: |
F24C
15/20 (20060101); F23j 011/00 () |
Field of
Search: |
;98/115K ;310/62
;417/423R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Perlin; Meyer
Assistant Examiner: Capossela; Ronald C.
Claims
I claim:
1. A blower unit for use in an air stream comprising a motor, a
blower wheel, and a housing surrounding the blower wheel, the
housing having first and second opposed side walls, the first of
said walls having an air inlet opening therethrough, the blower
wheel having opposing first and second sides disposed substantially
parallel with said first and second walls of the housing and having
an air inlet opening in said first side aligned with the opening in
said first wall, the motor being located external to the housing
and having operatively connected thereto a drive shaft which
extends into the housing through said second wall, the blower wheel
being operatively connected to said shaft for rotation thereby,
said second wall isolating the motor from the air stream entering
the housing, said second wall and the adjacent side of the blower
wheel being provided with adjacent aligned inwardly extending
recesses within which at least a portion of the motor is
positioned.
2. A blower unit as set forth in claim 1 wherein the motor is
positioned adjacent said second wall, and an opening is located in
the base of the recess in said second wall whereby a second air
stream may pass over the motor and into the interior of the
housing.
3. A blower unit as set forth in claim 1 wherein the motor is
affixed to and supported by the base of the recess in said second
wall of the housing.
4. In combination, a ventilating hood having walls forming a hood
shell and having therein a compartment with at least one open side
through which an air stream enters, and a blower unit within the
compartment and comprising a motor, a blower wheel, and a housing
surrounding the blower wheel, the housing having first and second
opposed side walls, the first of said walls having an air inlet
therethrough aligned with said open side of the compartment, the
blower wheel having opposing first and second sides disposed
substantially parallel with said first and second walls of the
housing and having an air inlet opening in said first side aligned
with the opening in said first wall, the motor being located
external to the housing and having operatively connected thereto a
drive shaft which extends into the housing through said second
wall, the blower wheel being operatively connected to said shaft
for rotation thereby, said walls isolating the motor from the air
stream entering the housing, said second wall and the adjacent side
of the blower wheel being provided with adjacent aligned inwardly
extending recesses within which at least a portion of the motor is
positioned.
Description
BACKGROUND OF THE INVENTION
Ventilating hoods are commonly installed over kitchen ranges or
assembled to the top of built-in wall ovens or the like. In
operation they conduct grease and vapor laden air through filter
means and then exhausts the air outside the hood and often outside
the kitchen. Motor-blower units are built into such hoods for
creating the desired air flow.
It has been found, however, that although electric motors are known
to experience increase in temperature when operated, such increase
in temperature is considerably aggravated when the air being
handled by the hood is at an elevated temperature. Extreme
temperatures tend to shorten the expected life of a motor and in
many cases motor designs are unacceptable because of the inability
of the motor coil insulation to withstand such heat without causing
electrical failures.
Attempts to avoid this problem have generally followed the approach
of combining the motor-blower unit with heat shields and/or
additional cooling devices for protecting the motor from exposure
to hot fluids or gases.
Conventional motor-blower units are generally constructed with a
squirrel cage blower wheel which is mounted for rotation on a motor
shaft. In order to achieve compactness, the motor is recessed into
the blower wheel by extending through an opening in one side of the
wheel and being attached to the opposite side of the wheel. Thus,
heated air must pass over the sides of the motor in order to enter
the blower wheel so as to be expelled outwardly by the wheel blades
into a suitable outlet such as a blower housing which is suitably
designed as a scroll or volute to properly direct the exhaust from
the hood.
It will be apparent that such problems will exist in any
application of conventional motor-blower wheel units of this
construction, such as air circulating units in or near chimney
flues, or other ventilating, cooling or anti-pollution
equipment.
SUMMARY OF THE INVENTION
The above and other disadvantages are overcome in the present
invention by the provision of novel means for protecting the motor
from the flow of heated air without the requirement of additional
shields or cooling ducts.
In accordance with this invention the blower housing has the usual
inlet aperture in one side which coincides and is aligned with a
corresponding inlet aperture in one side of the blower wheel within
the housing. However, the motor is not extended through these
aligned openings, as in prior devices of this character, but is
instead extended into a depression in the opposite side wall of the
housing and consequently into a similar depression in the adjacent
side wall of the blower wheel. The motor shaft is connected to the
depressed side of the blower wheel through an opening in the
depressed side of the housing. Thus, rotation of the wheel by the
motor will draw heated or other air into the blower wheel through
the inlet openings without contacting the motor.
If desired the opening in the housing, through which the motor
shaft extends, may be large enough so that some flow of cool air
from the opposite side of the housing is drawn over the motor into
the blower housing by inspiration.
Thus, the motor is at all times removed from the working fluid
without requiring the use of additional shields, ducts or baffles
for this purpose .
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objectives of this invention are achieved by
the structures shown in the accompanying drawings, wherein:
FIG. 1 is a vertical sectional view extending from front to rear
through a ventilating hood embodying the invention;
FIG. 2 is an enlarged bottom elevational view of the motor-blower
unit utilized in the hood of FIG. 1;
FIG. 3 is a slightly enlarged sectional view taken substantially on
line 3--3 of FIG. 2 looking in the direction of the arrows; and
FIG. 4 is a sectional view similar to FIG. 3 on a reduced scale
showing a modification in the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring more particularly to the drawings wherein like characters
of reference designate like parts throughout the several views,
there is shown in FIG. 1 a ventilating hood 10 embodying the
invention. Hood 10 may take any of the well-known shapes and
designs and may be constructed as a shell 12 having an open lower
surface 14 whereby the hood may be suitably mounted beneath
cabinetry or the like above a kitchen range. It is to be
understood, however, that the hood may be structured as an
accessory to or as a built-in part of the top portion of an oven,
if desired.
Within the shell 12 are provided two compartments 16 and 18.
Compartment 16 is defined by a pair of walls 20 and 22 suitably
dependent from the upper wall 24 of the shell. Means is provided in
the lower side of compartment 16 for supporting a light transparent
plate 28 which, if desired, may be frosted or otherwise made
diffusing. Suitably mounted within compartment 16 is a light source
28 which may be connected in any suitable manner to an external
electric circuit and which directs light downwardly through the
diffusing plate 26.
The second compartment 18 is substantially larger in size than
compartment 16 and may be defined by a wall 30 which depends from
the upper wall 24 of the shell and by the back wall 32 of the
shell. Means is provided at the lower end of the compartment for
supporting a filter 34 which is provided for filtering grease and
vapors out of a stream of upwardly flowing air indicated by the
arrows in FIG. 1. The filter 34 may be supplied with charcoal or
other filtering media as is well known. Within compartment 18 above
filter 34 there is provided a motor-blower unit 36 which is shown
in greater detail in FIGS. 2 and 3. Unit 36 includes three major
essential components, a motor 38, a blower housing 40 and a blower
wheel 42. In operation of a device of this character, the motor,
which may be secured to the top 24 of the hood as by a bracket 39,
will be actuated to rotate the blower wheel 42 within the housing
40 whereby hot air will be directed through an aperture in the
housing into the blower wheel which will function to direct the
incoming air out through an opening in the housing.
In well-known and conventional devices of this character the
assembly is such that the incoming hot air is drawn over the
surface of the motor before it passes into the blower wheel, thus
causing the temperature of the motor to be undesirably elevated as
pointed out hereinbefore. This is overcome in the present invention
without the requirement for additional shields or baffles to
protect the motor from the incoming flow of hot air. In accordance
with this invention the blower housing 40 may be of volute or
scroll shape embodying a cylindrical portion 44 (FIG. 2) and an
exhaust duct 46. The cylindrical portion is defined by an annular
first or lower wall 48 and a second or upper wall 50, which walls
48 and 50 are held in spaced apart relation by an encircling
peripheral or side wall 52. Thus, there is formed an enclosed space
54 within the housing within which is disposed the blower wheel 42.
The first or lower wall 48 is provided with a relatively large
inlet aperture 56 through which air passes into the device from the
range, oven or other heat source beneath the apparatus.
The second or upper wall 50 of the housing 40 is provided with a
cup-shaped depression 58 within which is disposed one end of the
electric motor 38. The operating shaft 60 of the motor extends
through an opening 62 into the interior of the housing and is
connected to the upper or second wall 64 of the blower wheel 42 so
that the blower wheel will freely rotate within the housing 40. A
suitable nut or hub 66 or the like is used to secure the shaft 60
to wall 64 of the blower wheel.
It will be noted that the blower wheel 42 is provided also with a
lower or first wall 68 which is disposed in spaced relation with
upper wall 64 and is fixedly connected thereto by blades or vanes
70 which are disposed at spaced intervals throughout the outer
portion of the wheel and which are radially disposed with respect
to the axis of the device. In order that the blades 70 will extend
throughout a sufficiently broad or wide area of the housing, it is
necessary that the second wall 64 of the wheel be also provided
with a cup-shaped depression 72 substantially the shape of the
depression 58 in housing 40 and spaced therefrom as shown. The
lower or first wall 68 of the blower wheel is provided with a
relatively large aperture 74 which generally coincides with the
aperture 56 in housing wall 48.
It will be apparent that when the motor 38 is operated, consequent
rotation of the motor shaft 60 will produce rotary movement of the
blower wheel 42. This will cause the hot air beneath the device to
be drawn upwardly through the filter 34 where grease and vapors
will be removed, and through apertures 56 and 74 into the interior
of the blower wheel 42, whereupon the air will then be exhausted as
shown by the arrows in FIG. 3 into the exhaust duct portion 46 of
the housing. From duct 46 the exhaust may be directed out of the
hood by any suitable and conventional means either directly into
the kitchen or externally thereof.
It should be noted that at no time will the hot air ever come into
contact with the motor 38 and thus the life of the motor is
considerably extended. However, since it is known that any motor
will, when operated, become somewhat higher in temperature than in
its non-operative condition, the wall 58 defining the cup-shaped
depression in the blower housing 40 is spaced slightly from the
adjacent portions of the motor so as to provide a passageway 76
therebetween through which cool air from above the housing will be
drawn by inspiration over the surfaces of the motor and through
opening 62 into the housing 40 where it will eventually be
dissipated with the exhausted hot air exiting from the exhaust duct
portion 46 of the housing. Thus, the motor 38 will remain
relatively cool at all times.
It may be desirable in some cases to provide a more positive
motor-fluid separation than is achieved in the structure of FIG. 3.
To accomplish this, as shown in FIG. 4, the rear wall 50 of the
housing is provided with the described cup-shaped depression 58 but
the aperture 62 therein is sealed by means of any suitable
mechanical sealing means 78, the operating shaft 60 of the motor
being rotatable within the seal 78, as is well known. The motor 38
then may be secured as by bolts or the like directly to the wall 58
of the housing if desired.
From the foregoing it will be apparent that all of the objectives
of this invention have been achieved by the structures shown and
described whereby an electric motor will be prevented at all times
from being contacted by the hot fluids which are being handled by
the device. It will be understood, however, that any modifications
and changes in the structures shown and described may be made by
those skilled in the art without departing from the spirit of the
invention as expressed in the accompanying claims.
* * * * *