US2206519A - Pipe bend furnace - Google Patents

Description

July 2, 1940.

J. H. TAYLOR PIPE am EURNAGE Filed Dec. 12, 153s s sheets-sneer 1 INVENTOR. TLmes ffa lTg4/lof ATTORNEYS.

July 2, 1940. J. H. TAYLOR 2,206,519

PIPE'BEND FURNACE Filed Dec. 12, 1958 3 Sheets-*Sheet 2 37 I 1 INVENTOR '1hr/26s Hall Tgyfof mi l'l ATTORNEYS.

. other related factors.

Patented July 2, 1940 UNITED s'mfras4 'Parlezvil'r OFFICE azoasis rmi BEND mueca James nan Taylor, oakrrk, nl. Appueanon neeember iz, 193s, serial No. 245,003

' s claims. (omas-5) This invention relates to furnace structures and has to do with a furnace for use in forming articles, such as pipe bends and analogous articles, from tubular blanks.

It is known to form articles, such as pipe bends. by passing tubular blanks over a suitable mandrel, the blanks being mounted upon a rod to which .the mandrel is secured and being forced over the mandrel by relative movement between the latter and the blanks lengthwise of the blanks. 'I'hat may be accomplished by either moving the mandrel rod and the mandrel lengthwise of the blanks, While restraining the latter against lengthwise movement, or by imparting lengthwise movement to the blanks while the mandrel and the rod remain stationary. Both methods are known in the art and need not be described in detail. In order that the blanks may pass over the mandrel and b e properly-formed thereby, they are heated to a proper working temperature, the material of the blank, its wall thickness, and Under present practice, the blanks are commonly heated by disposing the mandrel and adjacent portion of the mandrel rod Within a hood-like structure, the interior of which is heated by suitable' burners; That is obiectionable in that the hood-like structure referred to is open to the atmosphere for a conf siderable portion of its area, so that an objectionable amount of heat escapes to the atmosphere and is wasted, and in many instances the extent of heating of the blanks cannot -be'controlled with suflicient accuracy.

My` invention is directed to a furnace which is substantially closed to the atmosphere, preventingobjectionable loss of heat, in which the extent of heating of the blanks may be accurately Y controlled to suit various conditions, and in which the articles produced from the blank may be dischargedA from the furnace with expedition and facility and without risk of damage thereto. Further objects and advantages will appear from the detail description.

In the drawings:

Figure 1 is a plan view oi' a furnace embodying my invention; l

Figure 2 is a sectional view taken substantially online 2 2 of -Figure 1, on an enlarged scale;

Figure 3 is a sectional view taken substantially on line 3 3 of Figure l, certain parts being omitted and certain other parts being shown in elevation;

Figure 4 is a view similar to Figure 3 but showing a modied form of furnace embodying my invention;

Figure 5 is a sectional view similar to Figure 3, taken substantially on line 5 5 of Figure 6, on a reduced scale, but showing a second modified form of furnace embodying my invention; and

the temperature depending upon .Figure 6 is a sectional view taken substantially on line 6 6 of Figure 5, on an enlargedscale.

The furnace body is of box-like formation and of elongated rectangular shape in plane, as shown in Figure 1. Itcomprises a suitably reenforced plate metal casing 5 within which are'disposed two thick refractory side walls 8, which support a. thick refractory top Wall 1. The front of the furnace is closed by two doors 8 hinged to the furnace body at each side thereof, at 9, and normally held closed by a bar Ill engaged in suitable cleats I appropriately secured on the outer faces of the doors 8. At its frontupper portion the furnace is provided with burner block I2, defining an inwardly aring burner opening I3. which receives nozzle I4 of a gas burner I5 of known type, suitably mounted on block I2. Each of the side walls 6 is also provided with a burner block I2 thereon. Gas may be supplied to the burners through flexible hose I6 suitably attached thereto, or in any other suitable manner. It will also be understood'that any other suitable type of burners may be provided, using either gaseous fuel or liquid fuel. 'I'he body of the furnace thus defines interiorly a heating chamber, and the burners, disposed at the forward position of the furnace, provide means for heating that chamber.

A thick wall structure I1, of considerably increased thickness at its lower portion I'la, lits closely within the rearward portion of the furnace and extends throughout the cross-sectional area thereof, -providing a closure therefor. This wall structure is provided with a restricted openingl 8 therethrough, which openingacconimodates the side burners I5 are disposed below opening I8, at the lower or inner curved side of the mandrel 2|, whereas the front burner I5 is disposed above opening |8 and above the upper or outer curved side of mandrel 2|. being inclined downward and inward toward the mandrel, the side burners being inclined inward and upward of the heating chamber transversely thereof. 'I'he burners thus act to best advantage for heating to desired extent the blanks upon the mandrel and upon the portion 'of the mandrel rod I9 disposed within the furnace forward of the wall structure I1. Since the opening." is

and an associated burner I5 mounted restricted, `.with but sumcient clearance between-go this opening and the blanks on the mandrel rod I9 to permit escape from the' furnace of the products of combustion or waste gases, the furnace is substantially closed to the atmosphere and but little loss of heat occurs, rendering it possible to heat the blanks to the desired temperature and to maintain them at that temperature. Having the waste gases escape through opening I8 only is advantageous as being conductive to rapid heating of the blanks. In special cases, where less rapid heating of the blanks is desirable, the rate of heating may be controlled by opening one or both of the doors 8, or a bottom door, to be described presently, to an appropriate extent.

It is desirable, in the interests of quickly and accurately shaping the blanks to desiredform, that the blanks be heated in advance, within the furnace, to approximately the maximum temperatur'e which they can sustain without buckling when subjected to lengthwise pressure for starting the blanks onthe mandrel and then moving them along the mandrel rod and over -when the wall structure the mandrel. Blanks of various diameters and wall thicknesses are used, the size of the blank and its wall thickness, as well as the material of the blank, depending upon the articles to be formed. Accordingly, it is necessary, in order to attain the best results, that means be provided whereby the extent of heating of the blanks may be varied to suit conditions. That may be accomplished by-Vchanging the position of the wall structure I1, thereby changing the length of time during which the blanks are exposed to the heat within the furnace. With that object in view, two rack bars 22 are suitably attached, as by meansof brackets 23, t0 wall structure I1 adjacent the bottom and each side thereof. Rack bars 22 mesh with pinions 24 secured upon a shaft 25 rotatably mounted in two -pairs of brackets 26 and 21 secured to and projecting rearward from the furnace body. Each of the brackets 21 isprovided with a 4flange 23 extending over the adjacent rack bar 22 and restraining it against upward movement out of mesh with its associated pinion 24. Shaft 25 is squared at each end, at 25a, for reception of a suitable crank handle, by means of which the shaft may be rotated for adjusting. the wall structure I1 in. either direction. I It will be apparent that I1 is moved forward into its position indicated by dot and dash lines in Figure 3, the length of mandrel rod I9 extending into the heating chamber of the furnace, forwardly of wallstructure I1, is considerably less than it is when the wall structure I1 is in its full line position shown in Figure 3. Accordingly, with wall structure I1 in its forward position, the blanks upon the mandrel rod I9 are exposed to the heat within the heating chamber for a less length of time than is the case when wall structure I1 is disposed nearer to the back of the furnacev body. As a result,

the blanks are heated to a lower temperature,

when the wall structure I1 is in its forward l position, than when it is moved rearward. This adjustability of the wall structure I1 provides means whereby the temperature to which the blanks are heated preliminary to endwise passage thereof over the mandrel may be accurately controlled, and objectionable loss of heat is avoided.

The furnace body is provided with a disl charge opening 32 through its bottom, disposed beneath the mandrel 2l. This opening normally is closed by a door 30 suitably secured, at one side, to a pintle rod 3l -pivotally mounted, along one side of opening 32, in brackets 33 suitably secured to the bottom ofthe furnace body. Rod 3I is provided with a handle 34 projecting to one side of the furnace body and disposedv in Asubstantially horizontal position, when door 30 over the mandrel 2|, and has been formed into a pipe bend, the resulting pipe bend drops onto the upper face of door 39, through opening 32. The bend thus formed is discharged by swinging door 30 downward about the axis of pIntle rod 3 I, into such position that the formed bend slides off of the door, the latter being then returned to normal closed position by the counterweight means. Since the door 30 is opened but momentarily for discharge of a bend, objectionable loss of heat due to opening of the door is avoided.

The furnace body preferably is suitably mounted upon flanged wheels 36, which travel upon rails 31, in order that the furnace may be moved along the rails, atthe same rate as the rate of movement of the mandrel rod I9, in cases where the mandrel rod is moved lengthwise through the blanks and the latter are restrained against lengthwise movement. Such movement of the furnace maintains the mandrel 2I in the position within the furnace shown in Figures 1 and 3. In cases where the mandrel rod is held against lengthwise movement and the blanks are forced along this rod lengthwise thereof, and over the mandrel 2|, the furnace also remains stationary. Both methods are known in the art, as above noted, and need not be described in greater detail.

In the modified form of furnace shown in Figure 4, a stationary wall structure I1b extends throughout the entire interior cross-sectional area of the furnace, adjacent the back thereof,

and is provided with an opening I8a for accommodation of the mandrel rod I9 and blanks 20 thereon. A second wall structure 38, of L shape in section lengthwise of the furnace, extends forward and upward from wall structure I1b and denes therewith, and with the top wall 1 and upper portions of side walls 6 of the furnace, a dead air space 39. Wall structure 38 is provided, through its inner vertical arm, with an opening IBb corresponding to and aligned with opening I9a, for accommodation of the mandrel rod and the blanks mounted thereon. The blanks disposed within thedead air space 39 are eectively shielded from the intense heat within the heating chamber of the furnace, though they may be preliminarily heated to a certain extent within space 39. That may be advantageous, in certain cases, as providing means whereby the blanks than the former.

the blanks to a certainl predetermined `tempera-- ture, particularly if the heating of the blanks should be less abrupt than would be the case when using th furnace of Figures 1 to 3, inclusive.

'I'he modified form of furnace shown in Figures 5 and 6 is provided with a removable upper portion 1a, including a refractory top \wal1 1b, which seats upon the lower main body portion of the furnace. 'I'he latter is provided with a plate metal caseIa, thick refractoryl lining walls 6b, reinforced at their upper outer' edges by 'angle strips lll and thickened at their lower portions 6c and there converging downward to discharge opening 32a, and a counter-weighted door 30a controlling opening 32a Upper portion 'la is provided with al thick refractory lining forming continuations of walls 6b, and reinforcing angle strips seating upon strips 4l. Pins 42, welded or otherwise suitably secured to upper portion.-

1a, extend through plates 43 secured to thelower main body portion of the furnace, for accurately positioning thereon upper portion 1a. The latter may also be provided with a steel ring or loop suitably anchored therein, for convenience in removal and replacement thereof. Removal of upper portion 'la of the furnace gives ready access to the interior thereof for relining, repairs or other purposes.

Back wall structure |10, thickened'at its lower portion at i 1d, is provided with two openings lBc and |811, the latter lbeing disposed lower Each of these openings accommodates a mandrel rod I9 and blanks 20 thereon, there being a curved mandrel 2| secured to the inner end-of each rod, within the furnace, as before. 'I'he mandrel rod I 9 which extends through opening I 8d projects into the furnace a less distance than the rod extending through opening |8c, so that the longer or outer side of the lower mandrel is spaced below and in rear of the shorter or inner side of the upper mandrel, as shown inA Figure 5.' Two burner blocks I2 are mounted at each side of the furnace, one belowthe other, each carrying a `burner i5, the vertical distance between the two burners i5 being the same as the vertical distance between openings |8c and |811. Nozzles I4 of the two upper side burners are disposed on a line, transversely of the furnace body, a short distance below the inner or shorter side of the upper mandrel 2|,'and nozzles I4 of the lower side burners are disposed similarly relative to the lower mandrel, the upper burners at opposite sides of the body being thus disposed in a common vertical plane extending transversely of the body and the heating chamber, andthe opposite lower burners being similarly disposed in a common vertical transverse plane. Upper portion 1a of the furnace carries, at its forward end, a burner'block' l2 which is disposed at the transverse center of the on which is mounted a burner the nozzle of furnace and inclined downward and rearward thereof, as before, it being'noted that openings I8c and lsd, and consequently mandrels 2|, are

disposed at opposite sides of and equidistant from the central vertical lengthwise plane of the furs nace body and the heating chamber thereof. It

will be seen that the lower side burners are effective for heating the inner sides of blanks on the lower mandrel Il, and the upper side burners are eiective for heating the inner sides of blanks upon the upper mandrel 2|. The upper side burners are also effective, to a considerable extent,.i'or heating the outer sides of blanks upon Ato include all such variations,

, reception of mandrels reception of mandrels and blanks to be y.blanks thereon,

heating chamber the lower mandrel. Inthat manner the lessened heating effect of the front burner. with respect to the outer sides of blanks upon the lower mandrel relative to the outer sides 'of the upper mandrel, due to the latter being nearer the front of the furnace, is compensated for. That assures that both the inner and the outer sides of.blanks upon both mandrels are heated to substantially the same extent, which is conducive to uniformity of product and increased production. 'I'he burners also, of course, contribute toheating of the interior of the furnace.

While I preferably arrange the burners as blanks upon shown, in the several forms of furnaces illustrated, they may be arranged in other suitable ways. Also, if desired, the furnaces of Figures 1 to 4, inclusive, may be of multiple type and of proper width to receive any desired number, within limits, of mandrel rods vand associated mandrels, with blanks structure'of the furnace, in each case, being` appropriately formed to that end. As has been above indicated. changes in construction and arrangement of parts of my in" vention may be resorted -to without departing from the field and scope thereof, and I intend n as fallwithin the scope of the appended claims, in this application, in which the preferred forms only of my invention have been disclosed.

I claim:

be formed by endwlse movement over mandrels, a furnace body defining a heating chamber for and blanks to be formed, a wall structure clQsing the back of said chamber provided with two openings spaced apart transversely thereof and disposed one lower than the other blanks thereon, and twoburners at each side of the furnace bodyopening into Said chamber one disposed lower and further from the front of said heating chamber than the other.

2. In a furnace for heating tubular blanks to be formed by endwise movement over mandrels,

a furnace body defining a heating chamber for formed, a wall structure closing the back of said chamber provided with twoopenings spaced apart transversely thereof and disposed one lower than the thereon, the back wall` l. In a furnace for heating tubular blanks to the furnace body opening into said chamber one disposed lower and further from the front of said heating chamber than the other, the vertical distance between said two burners at each side of said body being the same as the vertical distance between said two openings.

3. In a furnace for heating tubular blanks to be formed by endwise movement over mandrels;

a furnace body defining a heating chamber for reception of mandrels and blanks to be formed, a wall structure closing .the back of said chamber provided with two transversely thereof and the other forV accommodation of mandrel rods and blanks thereon, said openings being disposed at opposite sides of and equidistant from the central vertical lengthwise plane of said heating chamber, two burners at each side of the furnace body opening into said chamber one disposed lower and further from the front of said than the other, and a burner opening into said heating chamber at the front thereof on said central plane.

.openings spaced apart disposed one lower than 4. In a rurnace for heating tubular blanks to be formed by endwise movement over mandrels, a furnace body defining a heating chamber for reception of mandrels and blanks to be formed, a wall structure closing the back of said chamber provided with two openings spaced apart transversely thereof and disposed one lower than the other for accomodation of mandrel rods and blanks thereon, said openings being disposed at opposite sides of and equidistant from the central vertical lengthwise plane of said heating chamber, two burners at each side of the furnace body opening into said chamber one disposed lower and further from the front of said heating chamber than the other, the vertical distance between said two burners at each side of said body being the same as the vvertical distance between said two openings and the upper and `lower burners at opposite sidesfof said body being respectively disposed in a common plane extending transversely of said body, and a burner .opening into said chamber adjacent the front and the top thereof on said vertical plane and inclined downward and inward of said chamber.

5. In means for forming articles from tubular blanks, a furnace comprising a body dening a heating chamber, substantially closed except for an opening in a vertical wall of said chamber,

a mandrel rod of substantially uniform diameter extending through said opening into said chamber to a length to accommodate a plurality of tubular blanks mounted end to end on said rod, a curved mandrel of gradually increasing diameter attached to the inner end of said rod, the latter and said mandrel being maintained in substantially fixed relation to said furnace, said opening being of a size to provide clearance about said rod and a blank thereon providing an outlet for combustion products eiective for inducing now of hot combustion gases aboutand along the mandrel rod and the blanks thereon, and burner means opening into said chamber for` heating it, said burner means being directed for the application of maximum heat at said mandrel with resultant ilow of hot combustion products about and along the'blanks on theA mandrel and rod within said chamber, whereby such blanks moved lengthwise on said rod through said opening into said chamber are gradually heated while traveling from saidopening to said mandrel where they are formed into pipe bends of enlarged diameter and .then

dropped within said chamber.

6. In means for forming pipe bends from tubular blanks, a furnace comprising a body defining a heating chamber, substantially closed except for an opening in a vertical wall of said chamber, a mandrel rod of substantially uniform diameter extending through said opening into said chamber, said opening being of a size to accommodate said rod and atubular blank thereon, a curved mandrel y of gradually increasing diameter attached to the inner end ofsaid rod and distanced from said opening, and means for heating tubular'blanks on said rod and mandrel. said heating means being directed for the' application of maximum heat at said mandrel and products of com-- bustion leaving said chamber through the clearance in said opening around said mandrel rod and blank thereon, whereby such blanks moved lengthwise on said rod through said opening into said chamber are gradually heated while traveling from Saidopening to said mandrel where they are formed into pipe bends or enlarged diameter and then dropped within said chamber.

7. In means for forming pipe bends from tubular blanks, a furnace comprising a body denning a heating chamber. substantially closed except for an opening in a vertical wall of said chamber, a'

mandrel rod of substantially uniform diameter extending through said opening into said chamber, said opening being of a size to accommodate said rod and a tubular blank thereon, a curved mandrel of gradually increasing diameter attached to the inner end of said rod and distanced from said opening, means for heating tubular blanks on saidrod and mandrel, said heating means being directed for the application of maximum heat at said mandrel and products of combustion leaving said chamber through the clearance in said opening -around said mandrel rod and black thereon, whereby such blanks moved lengthwise on said rod through said opening into said chamber are gradually heated while traveling from said opening to said mandrel where they are formed into pipe bends of enlarged diameter and then dropped upon a portion of the iloor of said chamber, and means for mounting said portion of said floor for` opening movement by the weightiof the pipe bends dropped thereon.

, 8. In means for forming pipe bends from tubular blanks, a furnace comprising a body dening a heating chamber, one wall of said chamber being adjustable to vary the length thereof, said being 'directed for the application of maximum heat at said mandrel and products of combustion leaving said chamber through the clearance in said opening around said mandrel rod and blank thereon, whereby suchblanks moved lengthwise on said rod through said opening into said chamber are gradually heated while traveling from said opening to said mandrel where Athey are formed into pipe bends of enlarged diameter and then dropped within said chamber. Y o' 9. In means for forming pipe bends from tubular blanks, a furnacecomprising a body denning a heating chamber, substantially closed at thev sides and top except for an opening in a side wall of said chambe a mandrel rod of substantially uniform diameter extending through said opening into said chamber, 'said opening being of a size to accommodate said rod and a tubular blank thereon, a curved mandrel of gradually increas.

ing diameter attached to the inner end of said rod and distanced ,from saidopening, and means forheating tubular blanks on said rod and mandrel, said heating means being directed for theapplication of maximum heat at said mandrel.

and products of combustion leaving said chamber said mandrel rod and blank thereon, whereby such blanks moved lengthwise on said rod through said opening into said chamber are gradually heated while traveling from said opening to said mandrel where they are formed into pipe bends of enlarged diameter and then dropped from said mandrel.

. 5 through the clearance in said opening around .mms naar. TAYLOR. u

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