US2157331A - Blowpipe - Google Patents

Description

H. s; GEORGE May 9, 1939.

BLOWP IPE Filed Dec. 24, 1936 FIG. I

INVENTOR HARRY S. GEORGE BY ATTORNEY- Patented May 9, 1939 UNITED STATES PATENT OFFICE? BLOWPIPE Application December 24, 1936, Serial No. 117,506

Claims.

This invention relates to oxy-fuel gas blowpipes and particularly to such blowpipes having a plurality of heating tips or nozzles for heating relatively large surface areas of metalbodies.

5 The present application is in part a continuation )f copending application Serial No. 688,335, filed September 6, 1933, now Patent 2,075,982, issued April 6, 1937.

In blowpipes of the typereferred to, for example, oxy-acetylene blowpipes, all of the acetylene and part of the oxygen required for complete combustion are supplied in definite proportions to a mixing chamber of the blowpipe. From this chamber the mixture passes through the nozzle of the blowpipe and, upon ignition, as it leaves the orifice of the nozzle, will burnincompletely if additional oxygen is not provided. The gases, however, emerge from the nozzle at a considerable velocity, and more oxygen is drawn by aspiration from the surrounding atmosphere into the combustion zone. The amount of oxygen drawn in from the atmosphere is even greater than in the supplied mixture and combustion is thus completed. Usually the nozzle is tapered toward its tip so as to facilitate the aspiration of the air and its proper mixing with the flame, for much of the air is drawn into the flame along the surface of the nozzle.

Under some conditions of operation objectionable effects are created by the flame reflecting or reverberating back around the nozzle. Among the causes of such objectionable reverberation are: the shape of the object being treated; operating in aconflned space; directing the flame normally against the object; and, combinations of these causes. With a multiple tip blowpipe these deleterious effects are increased. The back pressure of the reflected flame interferes with the aspiration of the atmospheric oxygen. Furthermore, the nozzle tends to become overheated and cause preignition or so-called backfiring of the mixed gases within the nozzle.

I have found that these objectionable effects of the reverberated flame can be overcome by the use of baffles, suitably constructed'and located with reference to the nozzle. The function of the baffle is twofold: first, to obstruct the reflected flame; and second, to decrease the area of the passageway around the extremity of the nozzle, thus increasing the velocity and pressure of the aspirated air drawn through this passageway. Thil latter effect counteracts the back pressure of the reflected flame, and also aids in cooling the nozzle by causing a more rapid circulation of cool air about the nozzle, The construction of the baffle should be such as to effectively prevent it from becoming overheated and radiating heat to the adjacent tips to an objectionable extent. Non-conducting refractories or metals having a low coefficient of con- 5 duction are undesirable for the purpose. I prefer to use copper or a copper alloy.

For some purposes, as for example, for intermittent operation of the blowpipe when heat treating successive rail joints in track, a copper 1o bafiie may be, and preferably is, made self-cooling by reason of being constructed massively and with suitable fins or exposed surfaces to dissipate the heat into the surrounding atmosphere. In other cases the baflle may be artificially cooled.

One of the principal objects of the present invention is to provide an improved multiple tip blowpipe in which the tendency of the blowpipe to backfire is substantially eliminated without the use of water cooling and its necessary additional equipment. Another object is to provide means for conveying heat away from the tips of a multiple tip blowpipe which may be introduced as attachments to such blowpipes without materially modifying the existing structural features 5 thereof. Other and more specific objects are: to provide a baffle which may be mounted upon, or formed integrally with, the multiple tip blowpipe, and which will increase the velocity and pressure of the air drawn in about the tips and prevent the reflection of the flames around the nozzles; and to provide a baflle constructed of a material having high heat conductivity and being capable of dissipating heat sumciently rapidly so that the material will not melt and backfiring may be eliminated.

The above and other objects and novel features of the invention will become apparent from the following description, having reference to the accompanying drawing, in which:

Fig. 1 is a fragmentary side elevational view of a pair of multiple tip blowpipes in which the principles of the present invention have been embodied, the blowpipes being particularly adapted for heating the tread surfaces of abutting rails;

Fig. 2 is an end elevational view, taken along the line 2-2 of Fig. 1, and showing further details of the baffle and one of the multiple tip blowpipes; and

Fig. 3 is a fragmentary perspective view, with portions broken away, of a pair of multiple tip torches with which a modified form of baffle is employed.

The present invention has been shown embodied in a multiple tip blowpipe or pair of blowpipes particularly adapted for heating the tread surfaces of abutting rail ends. It is to be understood, however, that the invention is not restricted in its use to such a blowpipe but the principal features thereof may be included in heating and/or cutting blowpipes generally, and particularly multiple tip heating blowpipes.

Referring now to the drawing and more particularly to Figs. 1 and 2 thereof, it will be seen that a source of high temperature heat H, suspended from a suitable support such as is shown in my copending application above referred to, is disposed over the end portions of the tread surfaces of abutting rails R for the purpose of heat treating said rails. The source of high temperature heat comprises a blowpipe or a pair of blowpipes B connected by means of conduits Ill to suitable mixing chambers and control valves for a source of gaseous fuel, such as a mixture of oxygen and acetylene or other fuel gas. Each of the blowpipes may include a manifold block H, to the upper side of which the conduits l are connected, and aplurality of nozzles or tips' l2 mounted in the lower side of said block. In the present instance each of the manifold blocks is provided with three closely adjacent transversely aligned tips l2 which are adapted to direct the flames produced at the orifices thereof against the tread surfaces of the abutting rails R. A pointer l3 may be provided in a suitable position on the side of each of the manifold blocks II and adjustably attached thereto by means of brackets I4. When the two blow- Pipes B of the rail heat treating apparatus are contacting each other as shown in Fig. 1, their respective pointers l3 form a single pointer for aligning the apparatus at a rail joint and properly positioning the nozzles or tips l2 with respect to the tread surfaces of the abutting rails.

As mentioned above, when a plurality of closely adjacent heating tips or nozzles are provided in a blowpipe of this or a like character, and the flames are directed normally against, an object, the deleterious effects of the reflected flames are increased with the result that the individual nozzles become overheated and backfiring may occur due to pre-ignition of the gases before issuing from the orifices of the nozzles. In order to overcome this tendency and to prevent mutual overheating of the nozzles a baffle or heat conducting member l5 is provided between the two blowpipes B. This baille may be removably secured to, but preferably insulated from, the underside of the manifold block Ii in any suitable manner and depend therefrom in a vertical plane substantially parallel to and between the transversely aligned nozzles or tips I2 and, as shown in Figs. 1 and 2, extends transversely across the rail. It will be understood, however, that if' only one multiple tip blowpipe is employed, such a heat conducting member may be arranged between individual groups of heating tips in the single blowpipe. Moreover, the baffle may also be used to advantage in conjunction with a single nozzle blowpipe. and/or may either partly or entirely surround an individual tip of either a single or multiple tip blowpipe.

Aside from being composed of a metal or alloy having high heat conductivity, the baffle or heat conducting member I5 is constructed or formed with sufllcient area and mass to dissipate heat rapidly from the exposed surfaces thereof. Thus a'substantial portion or area of the baffle is located out of the region of the, most intense heat and said baffle will remove or dissipate heat from such exposed surfaces; the amount of heat removed in this manner will be at least sufficient to prevent the radiation of enough heat from the baffie to the tips to cause backiiring. It will be apparent that, if it is found convenient; the baffle area outside of the zone of intense heat may be increased considerably over that shown in the drawing so that the surrounding air in such cooler regions will cool the baffle by conduction. It is sometimes advisable to water-cool the baffle, or the tips, or both.

Although the baffle I5 is shown in a transverse position in Figs. 1 and 2, it will be understood that in other instances it may be desirable to arrange the heat conducting member in a longitudinal position with respect to the nozzle block and the rail or other article being treated. Such an arrangement is shown in Fig. 3 where blowpipes B are positioned over the end portions of the tread surfaces of abutting rails R. Each of the blowpipes is provided with an L-shaped manifold block 2| having a plurality of tips or nozzles 22 mounted in the underside thereof. A baffle or heat conducting member 23 is suspended from the main apparatus (not shown) by means of supporting arms 24 and is disposed in a vertical plane on the underside of the manifold blocks and between at least two of the nozzles. In the present instance, however, the bafile is arranged longitudinally with respect to the rails R and extends a considerable distance on either side of the manifold blocks, though its function and performance are substantially the same as the bafile Hi. It will be noted that the substantially parallel walls of the baffle diverge at their lower ends adjacent the usual tapered portions of the nozzles to facilitate the aspiration of air as previously explained.

Although one form of baflle which extends transversely of the work and another form which extends longitudinally of the work have been described, it will be understood that in some instances, it may be desirable to employ a combination of two such battles with a single multiple tip blowpipe. Moreover, depending on the num-.

ber of tips employed and the resultant intensity of heat in the region of the tips, the mass and surface area of the ballle may be increased effectively. Instead of employing a solid baffle, air or oxygen under pressure may be caused to pass longitudinally of the nozzle to counteract the back pressure of the reverberated flame, and either to take the .place of, or augment, the aspirated air; or a solid baffle and air or oxygen under pressure may be used in combination.

Various other changes may be made in the construction and certain features thereof may be employed without others, without departing from the present invention or sacrificing any of its advantages.

What is claimed is:

1. A burner comprising a nozzle block adapted to be connected to a source of gaseous fuel a plurality of nozzles connected to said block for producing heating flames and a baflle arranged between. and parallel to at least twb of said nozzles and capable of removing heat from the region of intense heat adjacent said nozzles and dissipating such heat.

2. A burner comprising a manifold structure adapted to be connected to a source of gaseous fuel a plurality of nozzles connected to said structure for producing heating flames, and means comprisinga metallic baffle disposed bebetween at least two of the tips of said blowtween said groups or said nozzles and mounted on said structure for preventing backflring. I v 3. The combination with a multiple tip blowpipe adapted to produce a plurality of heating flames, .of a heat conducting member arranged or removing heat from the region adjacent said tips and dissipating such heat.-

5. A burner comprising a nozzle block adapted to be connected to a source of gaseous fuel; a nozzle connected to saidblock tor producing a heating flame, and means comprising a flat plate of heat conducting material secured to said block and disposed substantially parallel to said nozzle, said means being capable of removing and dissipating heat from the region of intense heat adjacent said nozzle and increasing the velocity of the aspirated air around said nozzle,

thereby to cool" effectively said nozzle and prevent backflring. V a

6. The combination with a multiple tip blowpipe adapted to produce a pluralityoi' heating flames, oi. a heat conducting member secured to said blowpipe and arranged between at least two or the tips thereof, said member having suflicient area and mass to conduct heat from the region of said tips to a point out of the region or intense heat and to dissipate such heat so as to prevent backilring in said blowpipe. r 'I. 'I'he with a blowpip having a plurality of nozzles for producing heating flames, o! a ccpper'baifle disposed between groups or said nomles for conducting heat from the region of said nozzles as to prevent backilrlng. 8. The combination with a blowpipe including a nozzle block having'a plurality of tapered nozzles mounted therein and extending downwardly therefrom, of a copper baflle comprising a flat plate removably mounted on said nozzle block vbetween groups of, said nozzles and extending downwardly from said block, said baflie having a widened portion adjacent to the tapered portions of the nozzles and being adapted both to increase the velocity of aspirated air about said nozzles so as to cool the same and to remove heat from the region of intense heat 4 adjacent said nozzles, and to dissipate such heat to prevent backflring-of said nozzles.

9. The combination with a blowpipe nozzle block having a plurality of nozzles secured thereto in such closely spaced relation as to cause mutual overheating and induce backfiring, or a heat conducting baiile arranged between at least two 01 said nozzles, said bailie being capwle of removing heat from adjacent said nozzles and dissipating such heat thereby to prevent backiirins.

10. The combination with a blowpip nozzle,

oi a metallic baflie comprising a substantially flat plate arranged adjacent to and parallel to said nozzle in a, position to conduct heat' from the region of intense heat adjacent said nozzle and to dissipate such heat, said baiile having surfaces parallel to the external suriaces of said nozzle whereby the velocity of the aspirated air about said nozzle is increased to cool the nozzle and prevent backflrlng. HARRY S. GEORGE.

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