US3026788A - Ventilator for wall oven - Google Patents

Description

March 27, 1962 w. A. sPEAR 3,026,788

VENTILATOR FOR WALL OVEN Filed o'ct, 1. 1958 4 sheets-sheet 1 15 1 V l 17 gf l 19 zz W //1.Z

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3,026,788 VENTILATOR EUR WALL OVEN Walter A. Spear, Cincinnati, .(hio, assigner to Nutone, Inc., Cincinnati, Ohio, a corporation ot New York nnen oet. 1, 195s, ser. No. 764,679 1 Claim. (Cl. 98115) This invention relates to ventilators adapted to carry away the odors and hot gases produced in cooking. More particularly, it relates to that class of Ventilating systems having an electrically operated blower and which are used in conjunction with built-in oven units ,or wall ovens, as they are commonly called.

Modern wall ovens may be heated by either gas or electricity. They are mounted internally of a framed structure which may be made contiguous with the wall of the kitchen, the front of the oven being flush or nearly so with a vertical wall panel presented by the structure. Inherently, they have a uniquely trim appearance and require less usable floor space in comparison with the ordinary range which stands on the floor. The oven unit, covered with a heavy layer of insulation, is suited to be located in a columnar structure of depth Suflicient to contain the oven entirely within it, so that the oven does notprotrude rearwardly of the back wall of the mounting structure.

When cooking with an oven, for example in roasting or broiling, one frequently finds it desirable to leave the oven door slightly ajar to vent the steam generated and to allow the hot gases to escape from the oven. Also, oftentimes, after the oven has been used it is desirable to leave the door ajar, simply for the purpose of cooling the oven more rapidly, the heavy insulation otherwise causing the heat to be retained inside the oven for an excessively long period of time. The hot gases being vented :usually are heavily laden with suspended grease particles and retain strong cooking odors. With the oven door open, these gases rise convectively from the oven, their general direction of movement being upwards, over the vertical surface of the structure in which the oven is mounted. Because the presence of such gases in the kitchen is undesirable, it is common to mount Ventilating means in the upward path of flow of the gases whereby they may be drawn out of the room into a duct leading to the outside of the building. A hood disposed immediately above the oven collects the hot gas, from which they enter a system directing them to the duct. To increase the rate of outward tlow of the gas and to permit the use of a smaller duct the installation of a blower is advantageous. An effective blower for this purpose is provided by a high speed centrifugal blower driven by an electric motor, the blower being located above the oven and rearwardly of the hood, that is, within the structure into which the oven is built.

However, two problems have arisen in connecion with the location of blowers of this type. First, to provide an ective rate of flow the blower must be of a substantial vsize and power. Yet, at the same time for appearance sake, it should be located entirely within the structure housing the oven. That is, it preferably should not protrude beyond the rear side of the struture. Furthermore, gas ovens require a ue to carry oit the combustion products produced by the burning of the gas. This iiue is also contained in the structure, and the blower unit must not encroach upon the space required for it. Secondly, as previously noted, the vapors drawn out by the blower are often laden with finely dispersed grease particles. These accumulate rapidly on the vanes and housing of the blower, necessitating its frequent removal and cleaning. In order to remove the blower for cleaning it must be connected from the duct and withdrawn from the structure in which it is located. While it is to be admitted that there are presently available units which are designed in a fashion `overcoming the trst of the problems posed, namely that of being capable of ting into the oven-containing structure, these blowers have not successfully met the second requirement, that of being readily removable. Because of their size and design characteristics, they are of necessity more or less permanently mounted in place, and therefore, impossible or at least very diflicult to clean. The same situation arises when it becomes necessary to repair or replace the blower.

The present invention has been directed at providing a blower which will meet both of the requirements posed. It is at once compact and readily removable for cleaning. In `its essential details it comprises a flattened blowercontaining package or housing having a front hood for collecting the vapors from the oven and an internal ducting and blower system leading rearwardly to a flue. 'Ihe motor and blower are mounted on ways so that they may be slid out of the housing as desired, and have a decoupling seal at the entrance to the ilue so that, when being slid out, the blower unit automatically detaches from the fixed members of the exhaust system. The blower housing has a removable face plate, the removal of which will permit the blower to be withdrawn through the opening so provided.`

While there are often physical embodiments of the invention which will be apparent to those skilled in the art, a preferred embodiment of the system is shown in the accompanying drawings, in which:

FIGURE l is a front View of a built-in oven installation, showing the hood and face panel of the exhaust unit comprising the invention situated immediately above the oven.

FIGURE 2 is an enlarged front view of the face panel, l

the hood having been removed.

FIGURE 3 is a top View taken through plane 3-3 of FIGURE l showing the general arrangement of the blower within its housing.

FIGURE 4 is a sectional side view of the installation taken through plane 4-4 of FIGURE 3. i

FIGURE 5 is a sectional view through the installation taken through plane 55 of FIGURE 3.

FIGURE 6 is a plan view of the motor bracket.

FIGURE 7 is an end view of the blower motor.

The general aspect of an installation having a wall oven and blower above it is shown in FIGURE. l. An oven, which may be either of the gas or electrically operated type is shown generally at 10 having an oven door 11, a control panel l2 located directly above it and a broiling oven door 13 directly below it. The oven door 1I is hinged along its bottom edge, so that it opens from the top. In the drawing, the oven is depicted as being installed in a columnar structure 14 having vertical side -walls l5 and 16 spaced apart from one Vanother at a distance suicient to permit the oven unit 10 to be installed within it, and of a depth at least equal to the depth of the oven. Gas-burning ovens require a line to permit the escape of combustion products formed inside the oven. The flue, which usually originates at the roof of the oven where the hot gas accumulates, may lead up the inside of the housing structure 14 to a chimney, or it may lead via a right angled turn directly out the rear of the structure, as where, for example, the rear of the structure is contiguous with the outside walls ofv the dwelling. In any event, the ue is customarily located toward the rear and side of the oven andvshown by the dot-dash circle designated F in FIGURE 3.

The exhaust ventilator comprising this invention is mounted directly above the oven unit 10 and is entirely contained within the same structure 14 which houses the oven. A hood 17 having an angulated top surface 18 and ends 19, which hold the top in its angulated attitude, is mounted so that the hot gases which escape from the oven when either of the doorsis opened rise and are collected by the hood. When the blower is operating it creates a partial vacuum in the region 20 under the hood so that the oven vapors are pulled by the draft thus created into the ducts and thereby prevented from escaping into the kitchen.

Along their rear edges, the hood ends 19 have locking tabs 21 or similar means by which the hood is demountably attached to a face plate 22 which is substantially ush with the surface of the structure 14 housing the oven. As is best seen in FIGURE 2, which shows the face plate with the hood removed, the face plate holds a centrally disposed air lter, generally designated 23, through which the indrawn gases pass in their flow path to the blower. The face plate is essentially a frame for holding the lter, and is fabricated so as to provide a set of offset tabs 24 which define and delimit the space in which the lter 23 is mounted. The attachment of the filter is preferably by a simple frictional fit, the tabs 24 positively preventing its rearward movement and a detent catch 25 frictionally preventing its forward movement. It is the purpose of the filter to remove from the air drawn through it the larger dirt and grease particles, so that what emerges is at least somewhat cleaner and thus less likely to clog the blower itself. The filter itself comprises no part of the invention and is not specified herein. It may be any of a number of commercially available air filters, having for its cleaning element, for example, a mesh of aluminum strands. The lter is removable from the face plate and may be cleaned (aluminum ltering elements may be washed in soapy water to remove the accumulated grease from them) or replaced as the need should arise. The face plate 22 has a switch 26 mounted in it by means of which the blower may be selectively turned on or off, and is removably held to the internally residing blower housing proper by means of thumb screws 27 which thread onto studs extending from the housing through holes in the face plate. The face plate, it will be apparent, is in reality only a finishing plate. As stated previously, the hood is removable from the face plate to aid in installation of the latter member as well as to permit the hood to bev cleaned.

FIGURES 3, 4 and 5 show the details of the housing and blower. The side walls 15 and 16 of the oven column 14 are spaced to receive the oven and the blower unit above it. The blower 28 is packaged in a flattened housing 29 which may be of sheet metal, having a top member 30 and bottom member 31 joined with the side walls 32 and an inward end wall 33. As in FIGURE 3, the housing may be of trapezoidal outline, though of course .the particular shape is not critical. The walls of the housing are joined together along their edges by any suitable means, such as the tabs 34 shown which are spot welded to the adjoining surfaces. It is the function of the housing to direct the gases from the filter 23 rearwardly to the inlet to the blower 28, and to provide a rigid frame whereby the blower is held in proper alignment with the flue to which it is demountably coupled. A corner bracket 35 stiffens the housing in the region adjacent to the face. The forward or front part of the housing is positioned in a vertical cutout area provided in the face of the column, and rearward rests on `a supporting beam which is not shown. It is positively held in the column by screw means 36 stationed behind the face plate 22. An advantage inherent in this use of an integral, prefabricated housing arrangement is that the entire system is packaged, so that it may be installed as a unit by the builder, leaving only the face plate and hood to put in place after the structure has been finished and the electrical wiringv completed.`

The blower is indicated generally at 28, and it includes an electric motor 37, a drive shaft 38, which drives the impeller vanes 39 through a hub coupling 40. The vanes 39 are encased within a convolute envelope 41. In its fundamental concept the blower is standard, and is not further specified. As can be seen from the drawing, the impeller vanes turn about a vertical shaft so that the plane of their rotation is horizontal and is parallel to the top and bottom members 30 and 31 respectively of the housing. The envelope 41 by reason of its modified spiral shape is intrinsically longer in dimension from front to back than it is from top to bottom, so that by orienting it within the housing in this attitude, the use of a relatively thin housing package is thereby afforded. This in turn provides a greater amount of utilizable space above the blower unit. For example, storage cabinets may be installed above the blower. Were the blower oriented in a right angled attitude, that is, so that the spindle were horizontal, it can be seen that the envelope would occupy considerably more of the otherwise useful cabinet space above the unit. In that event, two equally unsuitable alternatives would present themselves. Either the cabinet base would have to be located higher, which would be inconvenient for the housewife, or else the blower would have to be located behind the cabinet, where it would be inaccessible and which location would call for cabinets of less depth. Consequently the advantage of the arrangement disclosed are manifest.

The blower envelope 41 rearwardly conducts the high velocity gases through a throat 42 into a rear duct passageway 43 leading to a gasketed coupling with the flue at the rear wall 33 of the housing. The rear wall is provided with a telescoping sleeve 44 adapted to interft with the flue, which is not shown. The rear duct 43 in the configuration shown is fabricated of stamped sheet metal halves 45 and 46 which are joined together by spot welds along side flanges 47. A similar fabrication has been shown for the blower envelope. However, these are equivalent means of fabrication, both of these members might be made as one for example. The upper surface 43 of the envelope lies closely proximate the housing top 30 and the duct 43 downwardly leads from the throat 42 to the flue outlet and sleeve 44l which are vertically centered in the rear wall 33. At that wall, the v rear duct terminates in an abutment face 49 parallel to the wall 33; a felt gasket ring 5G secured -to the face 49 provides the pressure seal between the duct 43 and the outlet flue. It has been determined that the air pressure created in the rear duct by the blower is adequately contained by this felt gasket so that leakage and loss of pressure are negligible.

The blower unit is slidably suspended within the housing from two parallel overhanging ways 51. In the preferred configuration shown, these comprise rolled metal strips, each having an attachment surface S2 along which it is in facial contact with the underneath side of the housing top member 30, an offset 53 and a flange rail 54 spaced from the housing by the offset 53. Guide rails 55, which are essentially only tabs attached to the top surface 48 of the blower envelope and which protrude beyond its edges, are supported by the flange rails 54 and are slidable along them. At their front ends, the flange rails are rolled down to form lead-in lips 56 which permit the guide rails 55 to readily engage the flanges 54 to slide onto them.

The ways 51 are mounted so that they are perpendicular to the face plate 22 of the housing, and are positioned laterally so that when the blower is suspended from them, the felt gasket ring 50 on the abutment face 49 will encircle the ilue opening at the rear housing wall. When in use, the blower rotates at a high number of revolutions per minute and vibrations are thereby set up. Because of this, it has been found to be preferable that the offsets 53 be of such dimensions as to space the flange rails 54 from the housing top 30 at a distance equal to the thickness of the guide rails 55, `so that the rails are held between the anges and the top; this darnps the vibrations and promotes smoother operation of the unit.

It is by means of these guide rails that the blower is made removable. When -it becomes necessary to clean the blower vanes 39 of accumulated dirt and grease, or to make repairs on it, the hood i7 and face plate 22 are removed from the housing merely by taking oii the thumb nuts 27 and sliding the front panel off the studs. Then by reaching inside the housing and 'grasping the blower, it may be moved forward along the ways out of the housing. The rear duct is not physically connected to the flue; it is coupled only by the felt compression seal 50, so that a slight outward motion of the blower on the ways breaks the seal and decouples the blower from the liue. Thus, the entire unit including the rear duct is removable from the hou-sing. When relocating the unit in the housing, care need be taken only to run the blower in all the way on the ways, so that the gasket is again put under some compressional loadto -remake the seal.

The blower is indirectly urged upwardly into closer contact with the top housing member by a resilient boss 57 presented by the bottom housing member 31. In effeet, the blower is spring loaded between the two horizontal surfaces 3l) and 31, of the housing. The reasons for so holding the motor are two-fold; one, to prevent vibration by stressing the housing members and thereby diminishing their tendency, as lange thin panels, to act as sounding boards, and two, to rictionally hold the blower lfrom spontaneously moving forward on the ways and thereby breaking the gasket seal by relieving the gasket of the rearward pressure on it. The entire blower unit is held by means of this imposed spring load in a manner which will subsequently be explained, in a given fore and aft position between the face plate and housing rear wall. Because the blower motor, operating at -a high rate in a heated atmosphere requires cool-ing, this spring-load mounting is developed so as to provide an independent ducting system for clean coolant air of lower temperature, which is led through the motor and out the liuc. FIG- URES 4 and 5 show the details `of the preferred embodiment of this system, The bottom member of the housing contains an aperture 53 of circular outline directly beneath the motor 37. This aperture provides ingress for coolant air coming from the inside of the structure. While the oven when in use would heat this air to a slight degree, the oven is well insulated so that the air inside the structure remains relatively `much cooler than the hot gases drawn through the blower by the fan, and is eiective to keep the motor operating at a low temperature.

A circular region 59 around the coolant aperture 5S is r raised relative to the general level of the bottom housing member, forming the sides of the boss. Because the housing material is itself thin and resilient, this boss acts as a spring exerting a resilient upward force. A cylindrical spacing sleeve 6d attached to the motor at its upper portion rests, along its lower periphery 61 on the boss. Thus the entire blo-wer unit is urged downwardly into close proximity with the housing top member, the boss 57 bearing upon the sleeve 66, the sleeve impelling the motor 37, and the motor in turn transmitting the force to the envelope and rails. The spacing sleeve is of an inside diameter equal to the outside diameter of the motor, and has three vertical stakes 62 spaced around its upper rim by which it grasps the motor when fric-tionally pressed onto the motor. Fl-LGURE 6 shows the stakes, and FIGURE 7 shows the bottom of the motor 37, which has cooling ports 63 via which the coolant air drawn in through aperture enters. Situated around the top portion o-f the spacing sleeve at stations intermediately of the stakes are three indents 6d dividing the rim into three equal parts.

The blower envelope el is removably attached to a motor bracket 65 which in turn is connected to the motor, the bracket thus serving to couple motor and envelope. As shown in top plan in FIGURE 6 and in side view in FIGURES 4 and 5, the bracket is circular in outline and has Ia Lcircular central vent 66 through which coolant air may pass in flowing from the spacing sleeve 60 into and around the motor. An annular ring 67 bounds the vent 66 and contains drill holes V68 through which screws pass holding the bracket -to .the motor. This ring is of outer diameter equal to the inner diameter of the spacing sleeve, so that it may reside inside the latter member. Three arms 69 angulated upwards from the outer n'm of the ring 67 pass through the indents 64 on the spacing sleeve 60, resting on the lower edge of the indents, thereby centering and supporting the bracket and motor over the sleeve. At the upper ends of the angulated arms, they are attached to an inversely angulated conical Wall 7.0, residing directly beneath the vanes 39 of the blower. This band acts with the envelope, confining the high velocity gases in the envelope and substantially closing olf that region between the bottom of the vanes and the lower part of the envelope. At the lower .edge of the band is a horizontal attachment rim 71, which mates with the lower ,envelope half. Locking studs 72 are stationed around the rim of the lower envelope half, and these are engageable in cooperative openings 73 provided in the attachment rim '71. It is preferred to use locking studs of the type which have a narrow shank '74 and a large attened head '75 spaced above the envelope surface. The openings 73 are of a size suicient to admit the heads 75, and each have a narrow slot 76 extending circumferentially aw-ay from the opening 73 which will receive the shank 74 of the :stud when the envelope is i 'ven a slight twist about its axis. The heads 75 and slots 76 then coact to impose a restraint on vertical movement of the housing relative to the bracket. Radial ribs 77 formed in the bracket prevent the heads from moving in their slots, so that there can be no vibrationcaused separation of the bracket and envelope.

The manner in which the above described elements coact when the blower unit is removed from the housing aids in illustrating their function. When the blower unit is in place in the housing, it is held between the ways 51 and the boss 57 which bears upwardly on the spacing sleeve 60. The sleeve, contacting the bracket at the indents 64 through which the arms 69 pass, in turn holds the bracket while the latter connects the motor and envelope. As the unit is moved outwardly on the ways, the sleeve 6l) slides 01T the downwardly sloping sides 59 of the boss so that the upward force ceases to act on the sleeve. The sleeve remains held to the motor 37 by the stakes 62 which frictionally grasp the motor, and as an incident thereof the arms remain confined within the indents although the upward pressure on them is removed. The -blower may then be slid out the front of the housing, the face plate 22 having been removed. Once removed from the housing, the envelope 41 may be detached from the motor bracket 65, exposing and giving access to the vanes 39 by rst turning and then lifting the envelope relative to the bracket so that the locking studs 72 are disengaged from their correlative openings '73. The exposed vanes and the motor as well may now be cleaned of any collection of dirt or grease. The invention in this fashion provides the free accessibility of the heretofore relatively inaccessible blower and at the same time occupies a minimum amount of usable space.

The oven gas iiows as fol-lows in its passage through the package: It is collected by the hood and is drawn into the region of low pressure in the housing and immediately behind the filter, being partially cleansed of foreign particles in its passage through the filter. Itis drawn into the blower from below, entering the envelope 4l through the spaces between the arms 69 of the motor bracket; The vanes accelerate the gas to a high speed and it exists rearwardly through the throat l2 of the envelope into the rear duct 43 and out the flue. At the same time cool air from inside the structure passes into the housing through the coolant aperture 5S, up the sleeve 60 into and around the motor and at the top of the motor is mixed with the hot gas in the envelope. The arrows indicate the directions of ow in the drawings. In this operation, the sleeve 60 and the coolant aperture 58 insure that the air pulled through the motor is not laden with grease. This air comes from the space surrounding the oven below the bottom member or panel 31. Hence, the motor cannot become laden with greasy residues which prolongs its life.

Having described my invention, I claim:

A ventilator for a wall oven, said ventilator comprising a housing defined by top, bottom, side and rear walls, an exhaust outlet in said rear wall, an opening dened at the front of said housing, a filter disconnectably mounted across said opening, said bottom wall having a raised boss formed therein and an aperture in said boss, spaced parallel ways mounted from said top wall inside said housing, said ways extending perpendicularly to the front of said housing, a blower in said housing which is adapted to be removed from said housing through said opening, said blower comprising, an electric motor having a vertical drive shaft, vanes for the acceleration of air secured to said shaft above said motor, a generally flat convolute envelope secured to said motor and enclosing said vanes, said envelope having an air intake adjacent said shaft, said envelope having a throat portion extending to said exhaust outlet, means for making a compression seal between said throat and said exhaust outlet, guide rails mounted to said envelope adjacent the top thereof, said rails being slidably engaged with said ways whereby said blower is movable along said ways relative to said opening, said motor having cooling air intake ports at the bottom thereof, a sleeve extending below said motor, said sleeve having one end connected to said motor around said ports and having a lower end positioned for frictional engagement with Said boss around said aperture whereby air for cooling said motor is drawn in from below said housing through said aperture and sleeve into said ports.

References Cited in the le of this patent UNITED STATES PATENTS 2,464,473 Wessel Mar. 15, 1949 2,686,630 Burrowes Aug. 17, 1954 f 2,750,867 Meyer June 19, 1956 2,800,272 McKee July 23, 1957 2,828,683 Joseph Apr. 1, 1958 2,836,114 Weaver May 27, 1958 2,857,836 Bernstein Oct, 28, 1958 2,893,305 Jenson July 7, 1959

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