US2724908A - Oven construction - Google Patents

Description

NOV. 29, 1955 E M SHAW OVEN CONSTRUCTION Filed Aug.' 24, 1955 Edward /Z 672022) United States Patent OvEN CONSTRUCTION Edward M. Shaw, River Forest, Ill., assignor to General Electric Company, a corporation of New York Application August 24, 1953, Serial No. 375,899

3 Claims. (Cl. 34-105) This invention relates to baking and evacuation apparatus for the manufacture of electric refrigerators. In particular, the invention relates to an improved means for minimizing heat loss through an oven wall while providing for the passage of an evacuating machine manifold leading from a vacuum pump which is being drawn along externally of the oven during the operation of a conveyorized baking and evacuating system.

More broadly stated, it is an object of the invention to provide means for minimizing the escape of air, fumes, vapors, and the like, from an inclosed chamber or vessel through a wall of which extends a travelling support or other device.

It is still another object of the invention to provide for substantially closing a slot-like opening in a Wall of an elongated oven or other chamber or vessel by a structure which will open immediately in advance of, and close immediately to the rear of, a pipe, standard, or other device which extends through the structure and is being drawn along said slot-like opening.

It is a further object of the invention to provide a closure, as above noted, which except for a small area about the pipe or other device is substantially tight against the escape of convected or radiant heat from the inside of an oven chamber.

It is another object of the invention to provide a closure which will present a minimum of obstruction to the device as it is propelled or drawn along externally of the closure.

It is a further object of the invention to provide a closure which may be easily adjusted to accommodate wear on the elements thereof.

v Itis still another object of the invention to provide an improved construction for an oven or other chamber through or along which is passed apparatus to be treated v within the chamber.

y In many manufacturing processes, it is necessary to convey articles through heated baths, ovens or other structures which may liberate convected or radiated heat, or fumes or corrosive vapors, and it is the usual practice to support such articles on or from standards extending from a conveyor into the vator oven. In many cases, these standards extend through a slot in the wall of the structure and, because said slot must be amply wide to preventV the standard from striking or jamming on the side walls thereof, previous constructions have of necessity provideda relatively wide avenue of escape for heat, vapors and the like.

In a presently preferred form of the invention, I mount on each side-of the slot in the oven or other chamber a succession of brush elements arranged to have their respective bristles meet at about the Alongitudinal center line of the slot. Preferably, the brush elements are mounted on brackets fixed to the outside of the oven wall and are angularly inclined toward said wall so that their meeting point is approximately coincident with the wall itself.

Preferably, also, the bristles extend in the direction of travel of the apparatus passing therealong. The selection of bristle material is determined largely by the service requirements. Where the invention is used merely for the purpose of preventing heat escape, ordinary steel wire bristles may be satisfactory; for prevention of escape of corrosive vapors, or other similar difiicult service, the bristles may be glass fibers, or stainless steel, or other non-corrosive metal.

Other features and advantages of the invention will be apparent from the following detailed description of one embodiment thereof, read in connection with the accompanying drawing in which:

Fig. l is a somewhat schematic side sectional elevation of an oven and conveyor mechanism used for baking out and evacuating refrigeration systems;

Fig. 2 is a plan section, looking in the direction of .the arrows 2-2 of Fig. 1;

Fig. 3 is a perspective view of a brush mounting bracket looking from beneath, and illustrating means for adjusting the respective brush sections relative to the oven wall; and

Fig. 4 is a side sectional elevation of a two-tier brush arrangement.

The invention has been illustrated inv its application to apparatus for simultaneously evacuating and baking out refrigeration units. Accordingly, the apparatus includes an oven 1, having suitably thermally insulated walls and any suitable means for heating the oven. For example, the oven may be heated by an appropriate wattage of electrical heating elements 2, placed as required to provide the desired oven temperature. .The oven itself may be long, and, if space requirements demand it, may be arranged in a sinuous or looping pattern. In any event, the oven will have suticient length to evacuate and bake out refrigerator units to the desired standards in a single travel through the oven. As indicated, the bottom wall of the oven has a slot 3, said slot being coextensive with the oven for the accommodation of apparatus presently described. Suitably supported within the oven is a conventional I-beam type of conveyor rail 4. Said rail is supported so as to be centered on the slot 3. Carried by the rail are a plurality of conveyors such as the roller conveyors 5, each conveyor being linked together in suitably spaced relation by the chain or equivalent 6 which is driven by suitable motive power (not shown) to draw the conveyor through the oven at a predetermined rate. Each conveyor S includes some means for releasably supporting apparatus which is to be drawn kthrough the oven; as illustrated, said means comprises the hook 7. No attempt has been made to detail the conveyor or its drive mechanism, because it may be conventional in all respects and of itself forms no part of the present invention.

Below the oven and centered on the slot 3 is a conveyor, here schematically illustrated as tracks S and carriage 9, although any type of roller conveyor may be employed. Said conveyor carries for transportation along the length of the oven a high vacuum pump apparatus 10, said apparatus being electric motor driven and arranged to evacuate refrigerator units to the desired degree. The electric power for motor llmay-be derived from a third rail or trolley system (not shown) or by other conshown) and a complementary half i8 hinged at I9 to the extension i6. A suitable quick connect and disconnect clamp or latch 2@ provides for quickly securing the clamping collar about the pipe i2. .It will be seen therefore that as the frarne 16 is drawn along inside the Oven by the conveyor chain 6, the carriage 9 and its evacuation apparatus will, of necessity, travel at an equal rate.

Removably fixed to the frame i to be carried thereby is a refrigerator unit R comprising a motor-cornpressor unit 2l, condenser 22 (here illustrated as a fancooled condenser) and an evaporator 23. These elements are interconnected by the illustrated conduits, which provide for the circulation of liquid and gaseous refrigerant in a closed circuit, as is now well understood.

After the several components of the refrigeration unit have been assembled, the refrigeration system must be baked out to remove all traces of moisture and then evacuated to a very high degree. In the illustrated apparatus, the baking out and evacuation stages are correlative operations and are completed during a single traversal of the oven. At the entrance to the oven (not shown) an operator connects the evacuation tube I4 to the motor compressor unit 21, using a suitable quick-connect union fitting 24 with which the end of the tube I4 is supplied. It will be understood that a single vacuum pump apparatus may serve three or four refrigeration units, and that in such case there would be the required number of tubes i4 connected individually to the refrigerator units and passing through the guard pipe 12 to a header or equivalent (not shown) in the pumping apparatus.

Within the oven, of course, there are air movements created by natural convection currents and the passage of the relatively large area frame and refrigeration unit. There may also be fans or the like (not shown) for establishing a desired air circulation pattern for insuring proper heat distribution. In any event, such air movement may result in substantial heat escape through the slot 3, for it will be remembered that said slot is necessarily wide and coextensive with the oven.

To reduce heat loss in a manner which does not materially obstruct the entry of the pipe 12 into the oven or the travel of the pipe, I employ an organization of relatively thickly tufted brushes mounted on the external wall of the oven. As best shown in Figs. l and 3, I secure to the outer oven wall on each side of the slot 3, a series of rigid brackets 25, having brush mounting fianges 26 inclined at an appropriate anglefor example, 50with respect to the oven Wall. Said mounting anges support a series of brushes 27 by any suitable means; for example, by bolts or machine screws 28 passing through openings 29 in the base 30 of the brushes. As appears in Fig. 3, the openings 29 may be of elongated form to permit the brushes to be adjusted relative to the oven wall opening 3', obviously, the openings in flange 26 through which the bolts 28 pass may be elongated as well.

The material of which the brush bristles 31 are made will, of course, be dictated largely by the service requirements. In the illustrated application of the invention, the slot 3 is of the order of six inches wide and pipe I2 is of steel, four inches in diameter. The atmosphere within the oven is not corrosive. Steel wire bristles having a free length of approximately four inches, ex freely as the pipe passes along the slot and close quickly behind the pipe.

By inclining the bristles in the direction of travel, I obtain a smoother passage of the pipe 12 and insure that the bristles of opposite brushes come together in an overlapping relationship as they close behind the advancing pipe. Inclining the brushes in the vertical direction has the practical advantage of reducing the lost space bounded by the inner wall of the oven and the bristles. In addition, by inclining the bristles in the direction of travel, as well as in the vertical direction, the engagement of the bristles with the wall of the pipe is softer and of substantial area, thus distributing the wear on the pipe and bristles.

For most installations, the air spaces trapped by a relatively thick mat of bristles effectively bar the escape of heat or vapors. However, in extreme situations, it may be desirable to employ a plurality of brushes so as to engage the pipe or other device i2 at vertically spaced locations and to provide an air space between the brushes. Accordingly, as shown in Fig. 4, there may be employed a channel bracket 25.1 through an upper `liange of which will pass the bolts 28, and to the lower flange will be bolted the second series of brushes 27.1. The brushes 27 and 27 .ll may be of identical construction as to bristle density and material, or the respective brushes may be of diierent construction and composition, as desired.

It will also be understood that various brush compositions and arrangements may be employed at various locations along the oven or vat to accommodate locally existing conditions.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modications may be made therein, and it is intended to cover in. the appended claims all such modilications as fall within the true spirit and scope of the invention.

I claim:

l, In apparatus for simultaneously baking out and evacuating refrigeration units and the like, the combination of an elongated oven having a continuous slot in a wall thereof, a conveyor coextensive with said oven and disposed adjacent said slot-provided wall, evacuation apparatus arranged for movement along said conveyor and having a rigid tube extending through said slot into said oven, at least one refrigeration unit disposed within said oven and operatively associated with said rigid tube for movement with said evacuation apparatus, means for propelling said evacuation apparatus along said conveyor, and means including a series of brush elements arranged on said oven wall on each side of said slot and having relatively long, llexible, heat-resistant, bristles meeting at substantially the centerline of the slot for substantially closing said slot in front of and behind said rigid tube while separating about said tube to permit the passage thereof through and along said slot.

2. In combination, a wall deining a barrier between atmospheres having substantially dilferent physical characteristics, said Wall having an elongated slot-like opening therethrough, a conveyor extending along said wall adjacent said slot, apparatus arranged for movement along said conveyor and including an element extending through said slot in spaced relation with the side walls thereof, and means for minimizing the intermingling of the respective atmospheres while permitting travel of said element along said slot, comprising brush means disposed on each side of said slot and extending coextensively therewith, each said brush means having exible bristles resistant to attack by either atmosphere, said bristles of each brush having a length substantially greater than 50% of the slot width and meeting along the path of travel of said element, and means for removably mounting said brushes with the bristles thereof in angular relation to said wall to dispose the meeting ends thereof at substantially the plane of one of the faces of said wall.

3. An oven having at least one Wall provided with a coextensive slot through which may extend a rigid member operatively associated with apparatus disposed within said oven, said rigid member and apparatus being arranged for travel in the direction of said slot, brush means having relatively long, flexible bristles, said brush means extending coextensive with said slot along each longitudinal wall portion thereof, and bracket means secured to said oven wall and to said brush means to dispose the bristles of the respective brush means in angular relation to said oven wall in which said bristles incline in the direction of travel of said rigid member with the free ends of said bristles of opposite brushes meeting 2,281,079 along a line representing the line of travel of said rigid f 2,344,475 member. 2,557,621

References Cited inthe le of this patent UNITED STATES PATENTS lgg 2,073,669 Zademach Mar. 16,' 1937 Rollins Apr. 28', 1942 Turnbull n Mar'. 14, 1944 Touborg E June 19, 1951 FOREIGN PATENTS Sweden Jan. 27, 1906 Great Britain Tuly 22, 1937

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