US2288041A - Induction heat-treating apparatus - Google Patents

Description

, i NNNN JI.\M\\\\\\\\\\\ Jue 30, 1942. H. E. soMEsy INDUCTION HEAT TREATING APPARATUS oiginal'niled sept. 1v, 1937 LIE" INVENTOR `Howcnd E SOmes A TTORNE Y Patented June 30, 1942 2,288,041 INDUCTION HEAT-TREATING APPARATUS Howard E. Somes, Detroit, Mich., assignor to Budd Induction Heating, Inc., Philadelphia, Pa.,

a corporation of Michigan Original application September l?, 1937, Serial N0. 164,320. Divided and this tember 23, 1941,

Claims.

is a division of my copending No. 164,320, filed September This application application, Serial i7, i937.

The present invention relates in general to the heat treatment of objects by electromagnetic inparticular, to improvements in inductionheating heads for use in connection therewith.

ln a copending application Serial No. 50,829, led November 2l, i935, now Patent No. 2,256,873, dated September 23, 1941, there is shown and described an induction heating head which is particularly adaptable for heating hollow Worle-= Heretofore; it has been impossible in low turn stationary inducing coils to attain the desired extreme uniformity in the application of the heating energy, particularly as to the rate or energy input and the total amount of energy applied throughout an annular zone being heated. This is due to considerable extent to the necessity for current leads and the insulation thereence with uniform distribution of the magnetic flux. f

A further object is to provide an induction heating head with an improved organization of parts for circulating cooling medium through the A still further object is to provide an improved arrangement wherein the leads for the heating coil are arranged within the body of the induction heating head.

With the above and other objects in view,

which will be application Sep- Serial No. 411,963

apparent to those skilled in the art Referring to the accompanying drawing, the single view illustrates a suitable embodiment of the invention.

In the drawing in which like numerals refer to like parts, the heat treating head on which the coil 2i is mounted embodies a hollow mandrel i0 and a concentric, surrounding conductor sleeve il which is insulated from. the mandrel it by an intervening sleeve l2 of an electrically non-con-1 ductive material. i

The mandrel l@ and conductor sleeve il are connected with the terminals of a transformer secondary (not shown) in a manner and are supported in a manner shown in my copending application, Serial No. 164,320, aforesai i.

The lower end of the mandrel ill is formed with an enlarged tubular extension I3, there being a body it oi insulation material interposed between the shoulder I5 formed by the extension and a mounting iange I 6 sleeve II. The iiange I6 is secured to the mandrel I0 by means of bolts il (only one being shown) threaded through shoulder I5, a body I8 of insulation being intervened between bolts I i.

and metal of flange iii to prevent the passage of current between the shoulder I5 and flange I6.

'lhe mandrel lli tent than the outer extension i3.

The outer tubular extension I3 carries an iron core in the form of an annular series ofvtaperground radial laminations 20 seating at the bottom on a circumferential flange ZI at the lower end of the tubular extension 43, an insulation block 22 of rubber or other suitable non-conductor of electricity and of the same cross-sectional configuration as the laminations 20 being interposed at one point in the annular series of laminations, as shown at the left in Figure 2, for a purpose to be later described. The upper ends of the insulation block 22 and the series of laminations are engaged by a clamping ring 23, a nut 28, threaded on the extension I3, being provided to clamp the block 22 and laminations between the Ilange 2I and the clamping ring 23. In order insure annular alignment receive correspondingly shaped'annular projections 26 on the ange 2I and clamping ring 23 22 and the annular series vannular ring 30 clamped to the so that as the laminations are being clamped in position they will be caused to move into annular alignment.

The induction heating element is in the form of a tubular conductor 21 coiled about the block of laminations 20. The conductor is disposed within a peripheral recess in the laminations 20 and 'block 22 and is insulated, as shown, from the lamlnations. One terminal 2B of the conductor isl electrically connected with the inner tubular extension I@ through a radially extending conduit 23 which is fitted within an opening in the sidewall of an end of the inner tubular extension I3 by screws 3| shown). The portion of the conduit 29 which extends through the outer tubular extension I3 is electrically insulated therefrom by a body 32 of suitable insulating material. It is to be noted that the conduit 29 is in open communication with the interior of the annular lring 3B which, in turn, is in. open communication with the bore of the .tubular mandrel I3.

The other terminal 33, of/the conductor 2l extends radially through the outer ubular extension I3 and is insulated therefror by a body 3d of suitable insulationmaterial, and the end oi this terminal is electrically connected with and in open communication with the interior of an inverted cup shaped member' 35 which is secured in electrical contact by a cap screw @to a vertical conductor rod 5l.. The rod 5l extends through the radial wall of theA outer extension and through the flange it oi the sleeve il, to which such rod 3l is secured in any suitable manner, suchas for example, by brazing. it is to be nated that 'the conductor rod 5l is insulated from the wall of the outer extension i3 by a body 3@ of suitable insulating material. it is to be noted also that the terminals 28 and 33 are imbedded in the insulation block 22, thus insuring com Y plete insulation "for the same.

The electrical circuit of the coil 2i may thus y be traced from one terminal of the transformer (not shown), shown and described in my copending application Serial No. 164,320. aforesaid, through the mandrel ld and inner extension i5, conduit 29, and coil terminal, through the heating coil 2l and thenceirom upper terminal 33, member 35 and conductor rod 3l to the sleeve II and back to the other terminal of the transformer.

Itis thus seen that the leads or terminals for the induction heating coil 2li are arranged within the head proper and also such terminals are electrically connected to concentric tubular conductors insulated from each other with the result that none of such leads or connections are exposed to interfere with the operation of the heating head. y

It is to be notedthat the inwardly extend- -ing portions of the terminals dii and 55 are arranged one above the other and that by axially offsetting such terminals relative to the normal planes of the coil turns each unit turn of the coil is enabled to have a circumferential extent of 360 degrees. By so arranging the heating coil, attainment of the desired uniformity of application of heating energy throughout the annular zone being heated is enabled, also interference with the uniform distribution of magnetic flux is minimized.

The axial extent ofthe heating coil described is extremely short compared with the diameter so that the magnetic circuit if restricted in axial (only one being and the depth of the quenching operation as the head progresses.

lsuch as water under extent to several times less thanthe diameter, high density magnetic flux and consequently the depth of the treated zone may be kept smalband this regardless of the size of the workpiece.

IThe heating head of the present invention, as

set forth in my copending application Serial Noi 164,320, is of the type suitable for use in progressively heating cylindrical wcrkpieces and in connection with which a quenching nczzleis employed. The direction of movement, of course, of the heating head is such that as the head 4is moved through the cylindrical workpiece the coil 21 first heats the bore of the workpiece throughfollowed by the As viewed in the drawing such progressive moveout an annular zone which is .ment will be in an upward direction. The quench nozzle is associated with the bottom of the head and to which quenching fluid. pressure, is supplied through the extension |301" the hollow mandrel I0. The quench nozzle embodies a casting 40 engaged with the end of the outer extension I3 and havdit I'The casting 40 is ing an annular flange 4I tightly tting within the extension and a central annular hub 42 engaged with ring all through a sealing washer 43. cored out below the opening in the hub d2 to provide a chamber is which communicates through radial passages d5 (only one formed in a cylindrical portion il of reduced diameter at the lower side of the casting.

dit

, of reduced'diameter The quenching nozzle proper is provided by an annular ring i8 surrounding the casting it and abutting the end of the outer tubular extension i3, and a vclamping ring de which through the medium of cap screws 5t (only one being shown) clamps the casting iii and ring it against the end of the outer extension i3, the clamping ring having sealed engagement with the portion di to close the recess d5.

The ring 48 is provided with opposed circumferential ilanges 5I and 52, the flange 5I forming an annular chamber 55 and being axially 'spaced from shoulder or flange 2|^ to provide a circumferential quench passageway 54, and the flange 52 forming an annular chamber 55 and being axially spaced from the peripheral edge of ring 49 to provide a second circumferential quench passageway 56 axially spaced from passageway 54.

The annular chambers 53 and 55 are in communication through openings 5l (only one being shown) and the chamber 55 communicates with the closed recess d6 through a passage 58. It is to be noted that the casting it is provided with an axial passage 5a opening therethrough into outer and innerextensions and the casting llt. Additional passages, Such aspassage 5d, may be provided through casting 45.

As set forth in my appending application aforesaid, fluid fcr cooling the heating coil and for quenching is suppliedto the hollow mandrel Iii. The cooling fluid ows through the mandrel I3 to the lower end where a portion thereof flows through mandrel l ows from the chamber 44`y` through the radial passageways 45 and 58 to the cooling fluid through the coil 21 from the trailing terminal thereof to the leading terminal in the direction of progressive movement of the heating head through the workpiece.

It is to be noted that by arranging the open nozzle passage 54 at the underside of the abutment flange 26 for the core 20 an annular jet issues substantially directly from the lower edge of the flange 26 with the result that the zone of the initial contact of the quenching fluid with the workpiece is brought into' extremely close proximity to the trailing end of the heated zone which is the hottest portion of the heated zone advantage of the arrangement whereby the cooling uid is directed through the hollow conductor of the coil 21 from the bottom to the top, that is, in the direction of travel of the coil relative to the workpiece, is

through the workpiece with the result that it is the lowest terminal of the coil which is presented to the hottest part of the heated zone, this is the one selected for connection with the mandrel I0 whereby that portion of the coil is maintained at substantially the same potential as the workpiece.

struction. The particular manner of arranging the current conductingleads for the heating coil and the manner of cooling the coil materially add to the eflciency of operation.

It is to be understood that the invention may be embodied in What is claimed is:

1. An induction heating head comprising inner and outer concentric members of electrically conductive material, means electrically insulating said members from each other, an annular induction heating element surrounding one of said being electrically insulated from said last mentioned one member and being electrically connected to the other of said members.

2. An induction heating head comprising inner annular induction heating element surrounding said extending member and being supported of said inner member.

and being insulated therefrom.

8. In an induction heating head, a pair of concentric conductors insulated from each other, an annular magnetic core carried by one of said conductors, said core having a segmental block conductor, and the other of said 4 terminal connections for said coil, one of said connections extending through said block and being electrically connected with the supporting connections extending through said block and the wall of the supporting conductor and being electrically cony ynected 'with `the other conductor, said last mentioned connector being insulated from saidwall.

9. In an induction heating having an inner tubular extension and a concentric outer tubular .extension providing a chamber therebetween, an induction heating coil supported on said outer extension, said coil having a coolant-conducting passageway therethrough and tubular connectors of electrically head, a mandrelhaving an inner tubular extension and a conconductive material for the ends of said. coil extending throughhsaidouter extension, one of said connectorsI being in open communication with said chamber and the other of said connectors extending through the inner. extension'into open communication therewith, one of said connectors being in electrical engagement with said mandrel and the other of said connectors being l .insulated from said mandrel, and a conductor electrically .connected with said last mentioned "'connector. 1 f

11. In-an induction heating head`,`w`allmeans forming-a coolant-receiving chamber, wall means forming acoolant passageway lseparate l from said chamber, an. induction heatingicoil land supportedl b said f lrst mentioned wall passageway therethrough, and coolant-conducting connections of electrically conductive material for said` coil, each` extending through said first mentioned wall means', one of saidiconnections being' in J opens communication with., said chamber :and the otheroi said connections ex.- tending through said second Ainfentirmed wall means into open communication withsaid passurrounding -..means, saidfcoilflhavi'ng `a coolant-conducting;

nection for one end of said coil extending through said means for discharging coolant from said coil into said chamber and a second coolant conducting connection for lthe other end of said coil extending through said means, said head having an internal axial passageway therein connected with said second connection for conducting vcoolant thereto.

13. In an induction heating head, a coolantconducting heating coil, means within the annulus of said coil for supporting the same and forming a chamber,v a coolant-conducting connection for one end of said coil extending through said means for discharging coolant from said coil into said chamber and a secondcoolant conducting connection for the other end of said coil extending through said means, said head having an internal axial passageway therein connected with said second connection for conducting coolant thereto, said head having outlet means for said chamber 'opening from said chamber axially with respect to said coil.

14. Apparatus for progressively heat-treating a surface portion of an elongated workpiece by kelectro-magnetic induction comprising a supporting member movable longitudinally oi the surface portion to be heat treated, a hollow inducing element supported by and being movable by the supporting member relative to and closely adjacent the surface portion of the workpiece to be heat treated, the trailing end of said coil being susceptible to being heated by .the heat of the surface portion undergoing heating to a temperature higher than that of the leading end thereof, and means for directing. a cooling uid through the inducing element from thel trailing to the leading end thereof, whereby the cooling fluid first cools the portion of said coil which is at greater temperature to maintain said coil portion at substantially the same potential as the workpiece surface undergoing heating. y 15. Apparatus for progressively heat-treating the internal surface portion of an elongated hol- -`low workpiece by electro-magnetic induction comprising an annular supporting member, a tubular vinducing coil supported by and being movablevby said supporting member axially of the surface portion to be heat treated, and means for directing a cooling fluid through the inducing coil from theftrailing to the leading end thereof,

1 said supporting member having a chamber theresageway, one oisaid connections being electrically l insulated fromV said first mentioned wall means..

12. In an induction heatingfhead, a coolantconductingheating coil, means within the annulus of said coil for supporting the same and forming a chamber, a coolant-conducting conin, the Yleading end of said coil being in open communication with said chamber for discharging cooling iiuid into said chamber, said chamber having an exhaust passage for discharging the cooling fluid received thereby.

HOWARD E. SOMES.

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