US2856177A

US2856177A - Elevated furnace support structure

Info

Publication number: US2856177A
Application number: US524024A
Authority: US
Inventors: Lee Jess Max
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-07-25
Filing date: 1955-07-25
Publication date: 1958-10-14
Anticipated expiration: 1975-10-14

Description

Oct. 14, 1958 J. M. LEE 2,856,177

ELEVATED FURNACE SUPPORT STRUCTURE Filed July 25, 1955 2 Sheets-Sheet l JMAX LEE,

IN VEN TOR.

Oct. 14, 1958 J. M. LEE

ELEVATED FURNACE SUPPORT STRUCTURE 2 Sheets-Sheet 2 Filed July 25, 1955 E ww R 0 )0 7 ET 7 N h W Q B J Mk w m mg U f M,

United States Patent F ELEVATED FURNACE SUPPORT STRUCTURE Jess Max Lee, North Hollywood, (Iaiif.

Application July 25, 1955, Serial No. 524,024

6 Claims. (Cl. 266--4) This invention relates to improved quenching furnace units for heat treating metals.

In heat treating metal parts for many uses, it is desirable to first heat the part to a predetermined temperature, and then rapidly lower the temperature of the part by submersion or quenching? within a body of liquid. In my Patent No. 2,383,203 issued August2l, 1945 on Heat-Treating System, I have disclosed a furnace systern which is especially adapted for this type of heating and quenching operation. This system includes a furnace which is supported in an elevated location by a number of vertically extending support columns, and beneath which there is provided a quenching pit filled with liquid. An elevator is also provided for first moving a work load upwardly from a loading level into the furnace, then lowering the heated load into the quenching pit, and finally raising the load from the pit back to the initial loading position for removal from the elevator. The furnace has a door or doors at its underside adapted to pass the Work load and a portion of the elevator into and out of the furnace,

in a system of the above type, the elevated furnace is preferably connected to the vertical supporting columns by means of horizontally extending metal frame members, which extend along opposite sides of the furnace and are connected at their opposite ends to the vertical columns. In the past, difficulty has been encountered by reason of the longitudinal expansion of some of these horizontal frame members when they become heated, usually by heat which escapes fromthe bottom of the furnace past the doors. Specifically, such expansion of the horizontal frame members has had the effect of displacing or bending the vertical columns horizontally, with the result that the columns have been bowed substantially and the support of the furnace has therefore beenmaterially weakened.

The general object of the present invention is to provide an improved furnace system of this type, in which the horizontal frame members are free for longitudinal expansion without bending or bowing of the vertical columns to which they are connected. Specifically, I provide connections between these elements which allow relative movement between the horizontal and vertical members without impairing the support connection therebetween. For this purpose, I may employ a number of suspension members each of which is connected at an upper location to one of the vertical columns, and at a lower location to an end portion of one of the horizontal frame members. This suspension member effectively supports the furnace and yet is free for lateral flexure in a manner allowing expansion of the horizontal member without deflection of the vertical column. Connections of this type are desirably provided at each end of the two horizontal members. There may be a second pair of horizontal members, spaced above the first pair and out of the heated zone, and which may be directly and rigidly nections.

2,856,177 Patented Oct. 14, 195

"ice

The above and other features and objects of the present invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawings in which: I

Fig. l is a vertical section through a heat treating furnace and quenching system constructed in accordance with the invention;

Fig. 2 is a vertical section taken on line 22 of Fig. 1;

Fig. 3 is an enlarged fragmentary view taken on line 3-3 of Fig. 1, and showing one of the furnace supporting expansion connections with which the invention isp'articularly concerned;

Fig. 4 is a section taken on line -4-4 of Fig. 3; and

Figs. 5 and 6 are sections taken on lines 5-5 an 6-6 respectively of Fig.1. 1

, Referring first to Figs. 1 and 2, the heat treatingsystern there shown includes a furnace 10 supported by four vertically extending columns 11 at an elevated location spaced above the level of the'floor 12. Beneath the location of furnace 10, there is formed a quenching pit 13, which extends downwardly well below the floor line 12, and which contains a large body of water or quenching solution substantially filling the pit (say to the level L of Figs. 1 and 2). A hydraulically operated work supporting elevator 14 is incorporated in the apparatus, and is capable of receiving a work load W at floor level (see Fig. 1), then elevating that work load into furnace 10 for heating, and then rapidly lowering the work from the furnace into the body of quenching liquid within'p'it 13, to rapidly reduce the temperature of the work. At its underside, furnace 10 has a pair of horizontally sliding doors 15 which are mounted for movement toward and away from each other to allow passage of the work and an upper portion of the elevator into and out of the furnace. As will be apparent, the furnace, quenching .pit, and elevator are all preferably of essentially rectangular horizontal section. As will be discussed in greater detail at a later point, the invention is particularly concerned with the manner in which the furnace 10 is supported from the upstanding columns 11.

The elevator 14 includes a hydraulic cylinder structure 16 stationarily mounted in the lower portion of quenching pit 13, and slidably receiving a vertically movable plunger or ram 17, which is adapted to be hydraulically actuated upwardly from the Fig. 2 position to the Fig. 1 position when pressurized liquid is fed to cylinder structure 16 through a suitably controlled system represented in part by feed line 18. At its upper end, plunger 17 carries a horizontally extending frame structure 19, which may be laterally engageable with a number of vertically extending guides 20 for effectively guiding the elevator during its vertical movement.

Frame structure 19 is never received within furnace 10, but carries a second essentially horizontal platform or framework 120 which is spaced above structure 19 and is received within the furnace during a heating operation. Platform 120 may include twoparallel horizontal channel shaped tracks 21 which are horizontally alined with the floor line 12 in the Fig. 1 full line position of the elevator, and onto which the work W may be moved. Preferably, the work is carried by a suitable wheeled truck or carriage, whose wheels move along and are. supported by tracks 21. The two tracks 21 may be carried by several (typically three) transverse downwardly facing channel members 22, which are supported from frame structure 19 by individual vertically extending telescoping support posts 23 of externally cylindrical configuration. The

inner abutting edges of the two furnace doors 15 are provided with opposed semicircular recesses 24 of a. size to attached to the vertical columns without expansion conreceive posts 23 when doors 15 are closed with platform and the work positioned within the furnace 10, so that the doors embrace posts 23 and along with those posts a j '3' act to substantially completely close off the the furnace.

The rectangular or box like furnace is defined by two parallel somewhat elongated vertically extending side ,walls 25, two parallel end walls 26, and an upper horizontal wall 27. All of these walls are formed of suitable refractory brick or other heat insulative material, with the side and end walls typically being formed of several :layers of different types of refractory material as shown. The interior of the furnace may be heated in any suitable manner, as by suitable heaters represented at 28. The heated air may be circulated within the furnace by means of a blower 29 (or byi-nternal fans), with the circulating .air being directed along a desired path by means of suitable baffies and ducts 30. The refractory side and

end walls

25 and 26 are carried by metal castings 31 of the illustrated sectional configuration, and which extend across the undersides of the side and end Walls, and may project laterally outwardly beyond those "walls.

About the outside of the side and

end walls

25 and 26,

underside of there is provided an outer metal housing 32, formed of relatively thin vertically extending sheet metal. At its lower end, the sheet .metal 32 forming the outer housing of the furnace is confined within a rectangular framework formed by two outwardly facing channels 33 extending along opposite sides of the lower portion of the furnace, .and two similar channels 34 extending along the opposite ends of the furnace at its lower edge. These channels 33 and'34 may be attached to the outwardly projecting portions of castings 31, as'by means of a series of stainless :steel bolts 35 extending through and interconnecting the castings and the lower webs of the channels. At the four corners of the furnace. the

channels

33 and 34 are rigidly attached together, typically by means of an angle iron 135 (see Fig. 6) bolted to both of the channels being interconnected.

The end channels 34 project laterally beyond the rest of the furnace, and serve as tracks at opposite ends of 'the furnace. along which a number of rollers 36 supporting doors are horizontally movable. These rollers 36 may be .rotatably carried by frame members- 37 which project upwardly from opposite ends of doors 15, so that the doors are effectively supported for horizontal movement toward and away from each other to allow the work to pass into and out of the furnace. Doors 15 preferably contain a refractory or heat insulative material for preventing heat loss through the doors. The relatively sliding surfaces of the doors and furnace are of course preferably so formed or sealed as to minimize heat loss rigidly welded or otherwise attached in fixed relation to -the upper ends of the four supporting columns 11. Verti- "cally between the upper and lower channels, there may be provided a series of vertically extending rigid frame 'members 40 of T-shaped horizontal section, which .may

"be welded at their upper ends to

channels

38 and 39, and at their lower ends to channels 34 and a pair of channels or beams41,-and which act to assist in retaining and bracing :the side and end walls of the furnace.

The two channels 41 are provided for attachingthe "lower portion of the furnace to the four supporting columns 11 at the opposite ends of the furnace. These channels 41 extend horizontally along the opposite sides of the furnace, above the lower side channels 33, and arerigidly attached to channels 33, as by a series of spaced connecting bolts 42 whichconnect together the abutting webs of

channels

33 and 41, As in the .case of upper side channels 38, channels 41 project beyond the ends of the furnace for attachment to columns 11.

Each of the four columns 11 projects vertically upwardly from floor 12, and is attached in fixed relation to the floor at the lower end of the column by means of a suitable stationary base member 43, which may be bolted to the floor. The columns 11 are formed of structural steel, and are H-shaped in horizontal section (see Fig. 4). The webs 44 of columns 11 lie in planes which extend longitudinally oif the furnace, that is, parallel to side walls 25, while the flanges 45 of columns 11 project transversely with respect to the furnace. The two flanges 45 of each column 11 which project laterally away from the furnace are cut away at 46 to form a recess within which one end of one of the longitudinal furnace support channels 41 is received. The vertically extending web portion 47 of that channel 41 is then received directly adjacent the vertically extending web portion 44 of column 11 at the locations .at which flanges 45 are cut away.

The end of channel 41 is supported from column 11 in this position (see Figs. 3 and 4) by means of a vertically extending preferably metal suspension or tension member 48, which extends downwardly along one of the flanges 45 to a position opposite the end of channel 41. The upper end of suspension member 48 is rigidly attached to flange 45 at a location spaced above channel 41, preferably by means of a number of attaching bolts 49. At its lower end, suspension member 48 is attached by bolts 50 to a member 51 which is rigidly attached to channel 41. Member 51 may be a rigid piece of metal, plate or angle say about one-half inch in thickness, extending across the end of channel 41, and rigidly welded or bolted to channel 41 along the engaged portions of the web 47 and flanges of channel 41. The end of channel 41 may be retained against web 44 of column 11 by means of several, typically four, bolts 52 extending through openings 53 in column web 44, and through horizontally elongated slots 54 in web 47 of channel 41. Bolts 52 have enlarged heads at the outer side of channel 41, which heads are larger than and can not pass through slots 54, so that the bolts retain channel 41 against web 44 of the column, while at the same time allowing longitudinal movement of channel 41 relative to the column. Bolts 52 are sufliciently loose to allow such longitudinal movement of channel 41relative to the'column. As will be apparent, a connection such as that shown in Figs. 3 and 4 is provided between each end of each of the horizontal channels 41 and an associated one of the four vertical columns 11.

In using the illustrated furnace structure, elevator '14 is first so positioned that its work supporting platform 120 is alined with floor 12, following which a work supporting truck is rolled onto platform 120 along tracks 21. Doors 15 of the furnace may then be opened by suitable operating mechanism (not shown), and elevator 14 is then hydraulically actuated to raise the work W and platform 120 into the furnace. Doors 15 may then be closed beneath'platform 120, to close off the underside of the furmace and allow heating of the work within the furnace. After the work has been raised to a proper temperature, doors 15 are opened, and elevator 14 is allowed to fall rapidly to immerse work W within the quenching liquid in pit 13. After the quenching operation has been completed, the elevator is again raised to the Fig. 1 position, so that the work may be rolled ofii of platform 120, and a next successive load may be moved onto the platform.

During operation of a furnace of this type, a considerable amount of heated air may flow past doors 15 to the outside of the furnace, and usually results in the heatto expand longitudinally, and if the ends of these channels 41 are rigidly attached to columns 11, the expansion of channels 41 will result in the bowing of columns 11 in directions away from the end of the furnace. The unique expansion connections shown in Figs. 3 and 4 prevent such bowing of columns 11 even though channels 41 may expand. Specifically, when channels 41 are heated and begin to elongate, the suspension members 48 are able to flex, as between their full line and broken line positions of Fig. 3, so that the end of the channel 41 moves longitudinally relative to the supporting columns 11 without damage to either part. Also, such lateral flexure of the suspension member 48, which is in essentially a state of simple tension, does not in any way damage the suspension member. When the temperature of channels 41 subsequently reduces, members 48 merely flex back to their original vertical positions, without bowing of any of the columns 11 during either expansion or contraction. In order to allow for the desired flexure of member dis without damage to that member or any of the other parts, the portion of member 48 which is capable of flexure during expansion of channel 41 may typically be of a length of about 24 inches. The upper channels 38 at the top of the furnace may be rigidly attached directly to the upper ends of columns 11, rather than being connected by means of an expansion connnection such as that shown in Figs. 3 and 4, since relatively little of the heated air reaches the channels 38, and there is consequently no substantial heat induced expansion of these channels.

I claim:

1. Heat treating apparatus comprising an elevated furnace having an opening at its underside, a pit beneath said furnace containing a quenching liquid, an elevator for supporting work pieces and adapted to move said work pieces vertically between an elevated position in said furnace to be heated thereby and a lowered position of immersion in said quenching liquid, means for substantially closing said underside of the furnace with said work pieces supported therein by the elevator, and means for supporting said furnace including a pair of vertical support columns, a substantially horizontal member supporting said furnace and connected near opposite ends respectively of the member to said two columns, and an expansion connection between said member and one of said columns supporting the member from the column but allowing longitudinal movement of the member relative to the column when the member expands upon heating, said expansion connection including a vertically extending suspension element attached at an upper location to said column and hanging downwardly substantially directly vertically from said upper location and alongside said column to a lower location, means attaching said suspension element at said lower location to said member to suspend the member from the column, said suspension element having a thickness dimension longi tudinally of said member which is small as compared with the vertical length of the element, said suspension element being adapted to flex longitudinally of said member to allow said longitudinal movement of the member relative to said column, said one column being of essentially H-shaped cross sectional configuration having a cross web and flanges projecting therefrom, said horizontal member being a channel member having a web portion adjacent and parallel to said web of the column, said flanges having cutaway areas at the location of and receiving said channel member, and said suspension element being connected to one of said flanges of the column at a location above said cutaway area thereof, and being connected to said horizontal member at said cutaway area.

2. Heat treating apparatus as recited in claim 1, including a bolt carried by one of said webs and projecting through a slot in the other web to guide the member for only said longitudinal movement relative to the column.

3. Heat treating apparatus as recited in claim 2, including a connector disposed across and welded to an d end of said channel at the location of said cutaway area of said one flange and connected at that location to said suspension element.

4. Heat treating apparatus comprising an elevated furnace having an opening at its underside, a pit beneath said furnace containing a quenching liquid, an elevator for supporting work pieces and adapted to move said work pieces vertically between an elevated position in said furnace to be heated thereby and a lowered position of immersion in said quenching liquid, means for substantially closing said underside of the furnace with said work pieces supported therein by the elevator, and means for supporting said furnace including two beams carrying the furnace and extending generally horizontally and generally parallel along opposite sides of the furnace at the lower portion thereof and projecting beyond opposite ends of the furnace, two pairs of vertically extending columns supporting opposite ends of said two beams respectively, four expansion connections supporting the ends of said two beams from said columns but allowing longitudinal movement of the members relative to the columns at said connections when the beams expand upon heating, each of said connections including a vertically extending metal suspension element attached at an upper location to the associated column and hanging downwardly substantially directly vertically from said upper location and alongside said column to a lower location means attaching said suspension element to an associated one of the beams at said lower location to suspend the beam from the column, said suspension element having a thickness dimension longitudinally of the beam which is small as compared with the vertical length of the element, and said suspension element being adapted to flex longitudinally of the associated beam to allow said longitudinal movement of the beam relative to the column, a second pair of beams extending along and supporting said opposite sides of the furnace above said first beams and having their ends rigidly attached to said columns, said columns being H-shaped in section, and said two pairs of beams being channels having web portions adjacent the cross webs of said H-shaped columns, said flanges having cutaway areas within which said beams are received, four plates disposed across and secured to the ends of said channels, at approximately said cutaway areas of the column flanges, each of said suspension elements being bolted at an upper end of a flange of the associated column and at a lower end to one of said plates and being adapted to flex longitudinally of said beams, and a plurality of bolts carried by one of said webs at each of said connections and passing through slots in the: other web to guide the beam for only longitudinal movement relative to the columns.

5. Heat treating apparatus comprising an elevated furnace having an opening at its underside, a pit beneath said furnace containing a quenching liquid, an elevator for supporting work pieces and adapted to move'said work picees vertically between an elevated position in said furnace to be heated thereby and a lowered position of immersion in said quenching liquid, means for substantially closing said underside of the furnace with said work pieces supported therein by the elevator, and means for supporting said furnace including a pair of vertical support columns, a substantially horizontal member supporting said furnace and connected near opposite ends respectively of the member to said two columns, and an expansion connection between said member and one of said columns supporting the member from the column but allowing longitudinal movement of the member relative to the column when the member expands upon heating, said expansion connection including a vertically extending suspension element attached at an upper location to said column and hanging downwardly substantially directly vertically from said upper location and alongside said column to a lower location, means attaching said suspension element at said lower location to said member to suspend the member from the column, References Cited in the file of this patent said suspension element having a thickness dimension UNITED STATES PATENTS longitudinally of said member which is small as compared 370 Bataan Tan 1944 with the vertical length of the element, said suspension 5 Lee 1945 element being adapted to flex longitudinally of said mem- Lee Jam 1949 her to allow said longitudinalimovement of the member 2,641,575 Otto June 9, 9 relative to said column.

6. Heat treating apparatus as recited in claim 5, :in- OTHER REFERENCES eluding a slot and headed pin connection retaining .said 10 W. Trinks; Industrial Furnaces, vol. 1, page327 4Yh'ed. member against lateral separation from said column. 1950.