US3732802A

US3732802A - Ventilating hood and blower device therefor

Info

Publication number: US3732802A
Application number: US00125750A
Authority: US
Inventors: D Kristof
Original assignee: Caloric Corp
Current assignee: Caloric Corp
Priority date: 1971-03-18
Filing date: 1971-03-18
Publication date: 1973-05-15
Anticipated expiration: 1990-05-15

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.

Description

United States Patent [1 1 Kristof [54] VENTILATING HOOD AND BLOWER DEVICE THEREFOR 51 May 15, 1973 2,488,945 11/1949 Troller ..417/423 R 3,026,788 3/1962 Spear .....98/115 K 3,051,158 8/1962 Kimberley ..98/115 K 3,102,679 9/1963 Rudy 417/423 R 3,619,088 ll/1971 Bullock ..417/423 R Primary Examiner Meyer Perlin Assistant Examiner-Ronald C. Capossela Attorney Harold A. Murphy [57] 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.

4 Claims, 4 Drawing Figures r I y l i f 42 q 52 h F 62 60 47 70 1 I 68 o x H PATENTEU I 3.732.802

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 tendto shorten the expected life of a motor and in many cases motor designs are unacceptable oecause 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 sub stantially 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 l6 and 18. Compartment I6 is defined'by a pair of

walls

20 and 22 suitably dependent from the upper wall 24 0f 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. I. 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 ofa 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 baffies 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 ofthe 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 nonoperative condition, the wall 58 defining the cupshaped 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.

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 I 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 exing 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.

Claims

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.