US1988123A - Blowpipe - Google Patents

Description

Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE 1 Claim.

My invention relates particularly to that type of blowpipe that is commonly employed by practitioners of the dental profession and by chemists, jewelers, etc., and is especially directed to blowpipes that are designed to produce a fine needlelike flame and to burn illuminating gas of high calorific content intensified by a jet of pressure forced air.

Blowpipes as heretofore constructed failed to satisfactorily produce the desired slender needlelike flame as required in the fabrication of orthodontic appliances when employed to burn gases of high calorific content, such as natural gases.

The principal objects of my invention are to provide a blowpipe so constructed and proportioned that it may be employed to use either artificial or natural gases with substantially equal facility, and to produce a long slender needlelike flame of maximum heat efficiency.

Other objects of my invention are to provide.

a blowpipe in which the outlet orifice of the air nozzle is so related to the restricted outlet orifice of the gas nozzle that air is emitted therefrom directly into the condensed or constricted area of the stream of gas of high calorific content as it emerges from said restricted outlet orifice.

Specifically stated, the form of my invention as hereinafter described comprises a hollow body adjustably supported and having air and gas inlets and a nozzle provided with a restricted gas outlet orifice, an air tube connected with the air inlet and terminating in a tubular cylindriform extension of minimum diameter projecting through said nozzle and its orifice to a point slightly beyond the end of said nozzle.

My invention also includes all of the various novel features of construction and arrangement as hereinafter more definitely specified.

In the accompanying drawing, Figure 1 is a perspective view showing a common form of blowpipe of the type contemplated and conveniently embodying my invention; Fig. 2 is a central vertical sectional view of the blowpipe shown in Fig. 1, and taken transverse to the plane of the axes of the inlets; Fig. 3 is an enlarged transverse vertical sectional view of the blowpipe proper without the base or stand upon which it is supported, the section being taken in the plane of the axes of the inlet; Fig. 4 is a plan sectional view taken through the gas inlet on the line 4-4 in Fig. 3; and Fig. 5 is a plan sectional view taken through the air inlet on the line 5-5 in Fig. 3.

In said figures, the blowpipe comprises the hollow body 1 having the threaded boss 2 at its upper end and being bifurcated at its lower end to form the lugs 3, and provided with the bore 5 having the screw threads 6, and the counterbore '7 extending through said boss.

The body 1 is provided with the tubular nipples 9 and 10 respectively arranged to be connected by flexible tubing, not shown, with suitable sources of air and gas, the nipple 9 being connected with the bore 2 and the nipple 10 being connected with the counterbore '7.

A hollow cylindrical gas nozzle 12 is adjustably connected in threaded engagement with the boss 2, and forms the gas chamber 13, the transverse end wall 15 of which has the restricted gas outlet orifice l6.

Said transverse end wall 15 has a substantially flat outer surface, while its inner surface is substantially conical and so formed as to cause gas emitted from the chamber 13 under pressure to assume a conical film formation in which the angle of the conical walls is obtuse.

Air is directed from the bore 5 through the air nozzle comprising the tubular conveyer 17 which extends through the counterbore 7, being connected at its inner end in threaded engagement with the threads 6 of said bore 5, and being provided at its outer end with the extension comprising the tube 19 of minimum diameter, which extends through the gas chamber 13 and outlet orifice 16, and projects slightly beyond the outer end of the gas nozzle 12 and terminates at the apex of said conical film of gas.

As shown in Figs. 1 and 2, the body 1 is adjustably supported on the base 20, having the upwardly projecting lugs 21, which are pivotally connected by the links 22 and 23 with the lugs 3 on said body 1, said links being connected together by the screw pintal 25 and respectively connected by the pintals 26 and 2'7 with the lugs 21 and 3.

It may be here noted that the amount of projection of the air conveying tube 19 beyond the end of the nozzle 12, as well as the relative proportions of the cooperative parts of the blowpipe, are vital to its satisfactory performance in producing a slender needle flame from the mixture of natural gas and pressure forced air.

It will be obvious that the relative distance between the end of the gas nozzle 12' and the projected end of the air tube 19, may, if desired,

be conveniently varied either by axial adjustment of the tubular air conveyer 17 and its tube 19 in the bore 5 or the gas nozzle 12 on the boss 2 to obtain the most satisfactory results.

It is to be understood that the illustrations herein shown are as near as practical drawn to scale but, for convenience of illustration, the tube 19 is somewhat exaggerated in its diameter and that in the commercial device said tube is approximately one-half the diameter as that depicted.

Heretofore, in the use of natural gas through commercially known blowpipes it has been found difficult to prevent the flame being extinguished by the slightest current of surrounding air. However, this has been satisfactorily overcome by so forming the nozzle substantially flat at its outer end surface and conically inclined within so that its walls are so related as to form an obtuse angle at the apex of a cone if extended.

By such formation a condition obtains wherein a globular flame is formed at the base of the needle flame which prevents accidental extinguishment of said needle flame and maintains it in an ignited condition.

I do not desire to limit my invention to the precise details of construction and arrangement as herein set forth, as it is obvious that various modifications may be made therein without departing from the essential features of my invention as defined in the appended claim.

Having thus described my invention, I claim:

A blowpipe comprising inlets for gas and air, a nozzle forming an elongated gas chamber and having a transverse forward end wall provided with an outlet aperture and having its outer surface surrounding said aperture substantially flat and its inner surface converging as the surface of an obtuse angular truncated cone, causing the gas emitted from said chamber under pressure to assume a conical film formation, and an air conveyor extending through said chamber having an outlet aperture terminating at the apex of such conical film.

RUSSELL E. IRISH.

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