US2455447A - Flame treatment of substantially cylindrical internal surfaces such as bores - Google Patents

Description

Dec. 7, 1948. A. E. SHORTER 2,455,447

FLAME TREATMENT OF SUBSTANTIALLY CYLINDRICAL INTERNAL SURFACES SUCH AS' BORES Filed April 19, 1944 a Sheets-Sheet 1 1N VEN TOR.

ALBERT E. SHORTER VBY ATTORNEY 1943- A. E. SHORTER 2,455,447

FLAME TREATMENT OF SUBSTANTIALLY CYLINDRICAL INTERNAL SURFACES SUCH AS BORES Flled April 19, 1944 2 Sheets-Sheet 2 RELAY PANEL BUTTONS m m M c m m u Q VALVE Quavcu TIMER INVENTOR. ALBERT E. SHORTER A TTORNE Y Patented Dec. 7, 19458 UNITED STATES PATENT OFF-ICE FLAME TREATMENT OF SUBSTANTIALLY CYLINDRICAL INTERNAL SURFACES SUCH AS BEERES Application April 19, 1944, SerialNo. 531,787 In Great Britain May 13, 1943 8 Claims.

The present invention relates to the flame treatment of substantially cylindrical internal surfaces such as bores.

In the flame treatment of internal surfaces, such as bores, to effect, for example, the hardening of the surface layer, difficulty has been experienced in constructing a burner nozzle of sufflciently small dimensions to enable it to be inserted in the bore so that the flame impinges upon the surface to be heated without overheating localised zones of the bore, especially the marginal portions thereof.

In accordance with the invention, this difficulty is overcome by directing heating flames longitudinally into the bore from the opposite ends thereof so that the flames meet within the bore and in consequence are mutually deflected laterally to impinge upon the internal surface. By this means there is produced a dispersed flame which effects more uniform heating of the surface than is possible using a single burner nozzle, and by suitable adjustment of fuel pressure any risk of overheating the marginal portions of the bore, where the rate of heat conduction is minimum, is avoided. The heating flames may be produced by burners having single jet nozzles or multi-jet nozzles; for larger bores it may be of advantage to use annular multi-jet nozzles.

Where the rate of heat conduction from a given circumferential zone of the internal surface is uniform throughout such zone, the heating flames should be arranged to meet at a point or annular zone which is substantially equi-distant from the surrounding surface zone in order to effect uniform heating. Where the rate of heat conduction from the surface of the bore is nonuniform, the surface may be raised to a substantially uniform temperature by so arranging the flames that the distance between the surface and the zone Where the flames meet is a minimum in the region of maximum conductivity.

A further precaution which may be adopted to ensure uniform heating of the bore is to effect relative rotation between the bore and the flames about the central longitudinal axis of the bore. As an additional precaution to achieve uniform heating, especially where bores of considerable longitudinal extent are concerned, a relative oscillatory movement between the surface and the flames may be eflected in the longitudinal direc tion.

The invention has particular application to the surface hardening of bores of ferrous metals, and in such cases high temperature flames, such as are produced by the combustion of an oxy-fuel gas mixture, are preferred so that the temperature of the surface may be raised rapidly at least to the critical point, and the heated surface is then quenched. The quenching operation may conveniently be effected by means of two streams of quenching medium directed longitudinally into the bore from the opposite ends thereof so that the streams meet intermediate the ends of the bore and are thereby mutually deflected to impinge upon the heated surface.

Apparatus suitable for carrying the invention into eiiect may comprise two mutually opposed burner nozzles adapted to be mounted one at each extremity of the bore andto direct opposed flames thereinto so that the flames-meet within the bore to be mutually deflected laterally and thereby to impinge upon the surface to be heated. The nozzles may be adjustable relatively of the bore so as to vary as desired the point of mutual impact of the flames within the bore. As above mentioned, single or multi-jet nozzles may be used and to prevent overheating, they may be provided with passages through which a cooling medium, such as cold water, may be circulated.

The duration of heating may be determined automatically by means of a timing mechanism. For example, solenoidor thruster-operated valves may be provided for turning on and off the supply of gas to the nozzles, the solenoids being arranged to be energised periodically under the control of a timing device acting through suitable relays.

For surface hardening operations each of the opposed burners may be associated with a quenching device adapted to project a stream of quenching medium into the bore, the two streams being arranged to enter the bore from the opposite ends thereof and to meet intermediate the ends of the bore to be mutually deflected so as to impinge upon the heated surface. Quenching devices having single or multi-let delivery nozzles may be employed. In the case of multi-J'et nozzles, the orifices may be arranged to produce an annular jet of quenching medium.

Each quenching device may be mounted in spacedrelati'onship' with respect to its associated burner in which case relative movement between the bore and the heating and quenching devices must be effected on completion of the heating period in order to bring the heated bore into the quenching position. The movement from the heating to the quenching positions may be carried out automatically through a control device including timing mechanism adapted upon completion of a predetermined period of heating to elfect relative movement between the burner nozzles-and'the bore so as to bring the quenching devices-into operative position with respect to the heated bore and simultaneously to extinguish the heating flames and to turn on the supply of quenching medium.

Alternatively, burners combined. with quenching units may be employed adapted initially to heat the bore and then to quench the heated bore Fig. 3 is a fragmentary sectional View on the line III-III of Fig. 1,

Fig. 4 is an elevational view of an alternative apparatus substantially wholly automatic in operation, parts being broken away to show the operative mechanism.

Fig. 5 is a view on an enlarged scale of the front face of .a compound burner and quenching device incorporated in the apparatus shown in Fig. 4, and

Fig. 6 is a section on the line VI-VI of Fig. 5.

Referring to Figs. 1, 2 and 3, the work W having a bore, the surface S of which is to be hardened,

is mounted in a jig l secured to a slide l I carried by a bed l2 supported on a base plate I3. The slide II is coupled to a spring M by means of which it is moved, when released, from the extreme position, shown in Fig. 1, to another extreme position where it abuts against stops I fixed to the base plate l3. In the extreme position shown in Fig. 1, the slide II is prevented from moving under the action of spring I4 by a detent 16 which is urged into a recess H on the underside of the slide I I by means of a spring I8. Detent I6 is coupled through a pin Hi to the plunger 20 of a solenoid 2| adapted as hereinafter described to be energised periodically from a suitable source of electric current under the control of a timing device (not shown).

Opposed burner nozzles N supplied with a gaseous fuel from burners B are supported in brackets 22 and so positioned as to be in axial alignment with the bore when the slide H is in the extreme position shown in Fig. 1. Opposed quenching nozzles Q are also mounted in the brackets 22 and are so positioned as to be in axial alignment with the bore when the slide II is in the other extreme position abutting against stops In operation the work W is mounted in the jig with the slide ll held in the position shown in Fig. 1 with the detent l6 engaging the recess 11. The burners B are turned on so that the flames issuing from nozzles N enter the bore to be treated longitudinally and meet centrally whereupon they are mutually deflected laterally to impinge against the surface S. When the surface S has attained the critical temperature, solenoid 2| is energised to cause the withdrawal of detent I 6 from recess ll whereupon the slide II is propelled along the bed [2 under the action of spring I4 until it abuts against the stops (5 in which position the bore is in axial alignment with the quenching nozzles Q, and the heated surface S is quenched by the two streams which meet centrally in the bore and are mutually deflected to impinge upon the heated surface. On completion of the quenching operation, the work W is replaced by the next article to be treated, the slide I l is retracted to the position shown in Fig. 1 and the cycle of operations repeated.

The retraction of slide ll may be effected by means of a handle 23 secured to one arm of a bell crank lever 24 mounted on a pivot pin 25 journalled in a bearing 26 carried by a bracket 21 supported on the base plate l3. The other arm of the bell crank lever 24 is furnished with a slot 28 engaged by a pin 29 projecting from the slide ll. As will be immediately obvious from Fig. 3, movement of handle 23 in a clockwise direction will cause the slide H to return to the position shown in Fig. 1.

The turning on and off of the gaseous fuel to the burners and of the quenching medium to the quenching devices may be effected by means of solenoid-operated valves which, like the solenoid 2!, may be controlled by a timing mechanism through suitable relays adapted on closure of a master switch to cause initially the energisation of the gas valves, after a predetermined interval the energisation of solenoid 2| to release the slide II and immediately afterwards the energisation of the quench solenoids.

Reference will now be made to Figs. 4, 5 and 6 which show apparatus designed primarily for the automatic surface hardening of larger bores than can be treated with burners having single nozzles and where it is necessary to rotate the bore about its central longitudinal axis during the heat treating operation.

The work W, the surface S of which is to be hardened, is mounted on two parallel rollers, only one roller 40 being shown. The rollers are journalled in bearings 41 secured to a reciprocating slide 42. The roller which is not shown is simply an idler roller but roller 40 is a live roller being driven by a belt 43 coupled to the shaft of a motor 44 mounted on a bracket 45 also secured to the reciprocating slide 42. Roller 40 carries a fixed locating collar 46 and an adjustable collar 41 which serve to locate the work on the rollers and prevent longitudinal movement of the work relatively thereto. Slide 42 is coupled through a thrust rod 48 to an adjustable eccentric 49 driven by a second motor 50 and is supported on a machine bed 5| which is designed to serve also as a sump for collecting the quenching liquid which is drained therefrom through an outflow pipe 52.

Since the bore to be treated by the machine shown in Fig. 4 is substantially larger than that shown in Fig. 1, it is desirable to use multi-nozzle burners, and to simplify the procedure it is of advantage to combine each burner with a quenching device. The combined burner-quench units BQ are mounted in opposition at each end of the bore and are supported in clamps 53 carried in brackets 54 secured to the machine bed 5|. The burner nozzles are supplied with gaseous fuel through conduits 55 supplied through a solenoidoperated valve 56 mounted on a panel 51 affixed to the lower part of the machine bed. The quenching nozzles are supplied with quenching medium through conduits 58 leading from a solenoid-operated valve 59. A gas timing mechanism 60 controls in known manner the duration of heating,

. whilst a second timing mechanism 6| controls the duration of the quench, both said timing mechanisms operating through relays mounted on a re-- lay panel 62 to turn on and off the solenoid-operated valves 56 and 59. Where it is desired to introduce a pause between the heating and quenching operations, a third timing mechanism 63 may be provided for this purpose. Four push button switches are mounted on a panel 64 for controlling the cycle of operations. One push button starts the cycle, another stops the cycle at any instant, the third serves to turn on the gas supply for testing purposes, and the fourth serves to turn on the supply of quenching medium for testing purposes. The starting and stopping switches may also be arranged to control the starting and stopping of motors 44 and 59. A pilot jet 65 may be provided to ignite the burners at the beginning of each heating period.

The construction of the compound burnerquench units BQ is shown in detail in Figs. 5 and 6. The burner nozzles N are arranged round the circumference of a circle surrounding an orifice plate 66 through which the quenching medium is delivered. The nozzles N are connected through longitudinal passages 6? to lateral passages 68 connected to a gas inlet 69. The orifice plate 68 forms one wall of a distribution chamber 10 adapted to be supplied with quenching medium through pipe H In operation the work is mounted on the rollers and the burner-quench units BQ adjusted as shown in Fig. 4. The timing mechanisms 60, GI and 63 are set to give the required periods and the starting button on panel 64 is then depressed. This simultaneously starts motors 44 and to rotate and reciprocate the work and also turns on the gas supply to nozzles N where the jets are ignited by the pilot jet 65. The flames from the nozzles N meet centrally of the bore where they are mutually deflected laterally to impinge upon the surface S which, by virtue of the combined rotation and reciprocation of the work is uniformly heated both circumferentially and longitudinally. After a heating period determined by the setting of the timing mechanism the gas supply is cut off and, after a pause determined by the setting of timing mechanism 63, the supply of quenching medium is turned on and continues for a period determined by the setting of the timing mechanism 6|. At the conclusion of the quenching period, the supply of quenching medium is turned off by the operation of solenoid valve 59 and simultaneously the motors M and '50 are switched off to bring the work to rest. The burner-quench units BQ are then moved apart to permit the work to be lifted off the rollers and replaced by the next article to be treated.

What is claimed is:

1. Method of flame treating internal surfaces such as bores which comprises directing heating flames longitudinally into the bore from the opposite ends thereof so that the flames meet intermediate the ends of the bore and are thereby mutually deflected laterally to impinge upon the surface to be heated.

2. Method according to claim 1 applied to the flame treatment of a cylindrical bore, the rate of heat conduction from any given circumferentially extending zone of which is uniform throughout such zone, wherein said heating flames are arranged to meet at a point or annular zone which is substantially equidistant from the surrounding surface zone to be heated.

3. Method according to claim 1 applied to the flame treatment of a bore, in which the rate of heat conduction from the surface of the bore is non-uniform, wherein the flames are so arranged that the distance between the surface and the zone where the flames meet is a minimum in the region of maximum conductivity.

4. Method according to claim 1 which comprises effecting relative rotation between the bore and the flames about the central longitudinal axis of the bore in order to effect uniform heating of the surface in the circumferential direction.

5. Method according to claim 1 which comprises effecting between the bore and the flames a relative oscillatory movement axially of the bore in order to effect uniform heating of the surface in the longitudinal direction.

6. In a method for the surface hardening of substantially cylindrical internal surfaces of bores in articles of ferrous metals wherein heating flames are directed into the bore of sufficient intensity to raise the temperature of the surface rapidly at least to the critical point and wherein said heated surface is then subjected to a quenching operation to produce a surface having en hanced hardness, the improvement which comprises directing streams of treating medium longitudinally into said bore from opposite ends thereof so that the streams meet intermediate the ends of the bore and are thereby mutually deflected laterally to impinge upon the surface to be treated.

7. Method according to claim 6 wherein said quenching operation is effected by means of two streams of quenching medium directed longitudinally into the bore from the opposite ends thereof so that the streams meet intermediate the ends of the bore and are thereby mutually deflected to impinge upon the heated surface.

8. In the method of surface hardening ferrous metal articles, wherein heating flames are applied to the surface and are of sufficient intensity to raise the temperature of the surface rapidly to at least the critical point and thereafter quenching jets are applied to produce a surface having enhanced hardness, the improvement for treating substantially cylindrical internal surfaces such as bores. which com-prises directing mutually opposed streams of treating medium longitudinally into the bore from opposite ends thereof so that the streams meet intermediate the ends of the bore and are thereby mutually deflected laterally to impinge upon an annular zone of the internal surface to be treated, effecting relative rotation between the bore and the streams of treating medium about the central longitudinal axis of the 7 bore in order to efiect uniform treatment of the surface in the circumferential direction, and effecting relative reciprocation between the bore and the streams of treating medium axially of the bore in order to effect uniform treatment of the surface in the longitudinal direction.

ALBERT EDWARD SHORTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,264,?52 Groene Dec. 2, 1941 2,273,809 Kinzel Feb. 17, 1942 2,290,283 Jones July 21, 1942 2,295,272 Somes Sept. 8, 1942 2,302,164 Anderson Nov. 17, 1942 2,310,384 Arnoldy Feb. 9, 1943 FOREIGN PATENTS Number Country Date 441,329 Great Britain Jan. 17, 1936 523,823 Great Britain July 23, 1940 803,690 France Oct. 6, 1936

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