US2343958A

US2343958A - Cutting tip with diverging outlet

Info

Publication number: US2343958A
Application number: US369018A
Authority: US
Inventors: John J Crowe
Original assignee: Air Reduction Co Inc
Current assignee: Airco Inc
Priority date: 1940-12-07
Filing date: 1940-12-07
Publication date: 1944-03-14
Anticipated expiration: 1961-03-14

Description

March 14, 1944. J; J CR WE 2,343,958

CUTTING TIP WITH DIVERGING OUTLET Filed Dec. 7, 1940 4 12 yam y x; 17 2 (My 2 ATTORNEY Patented Mar. 14, 1944 UNITED STATES PATENT OFFICE 2,343,958

CUTTING TIP WITH DIVERGING' OUTLET John J. Crowe, Westfield, N. J., assignor to Air Reduction Company, Incorporated, New York, a N. Y., a corporation of New York Application December 7, 1940, Serial No. 369,018 2 Claims. '(Cl. 158-27.4)

This invention relates to tips for oxygen cutting torches, and more particularly to improvements in the construction and methods of con- I structing such tips.

Improved cutting results are obtained with oxygen jets having velocities greater than the velocity of sound, provided that such jets can be prevented from expanding laterally after their discharge from the tip. A jet that remains cylindrical, or approximately so, can be obtained creases in cross-section to a constricted throat beyond which the passage diverges toward its outlet end with agiven longitudinal curvature, the radius of which increases progressively to ward the outlet end of the passage, the cutting results are not only improved, but the same tip can be used with a wide variety of oxygen pressures and the number of tips required for cutting the entire range of work thicknesses isgreatly reduced. Because of the change in curvature, from convexat the throat to concave where the walls diverge beyond the throat, the passages cannot be drilled. They aremade by rolling or drawing with suitable mandrels.

It is an object of this invention to provide an improved divergent tip construction in which the part of the tip containing the diverging jet passage ls a difierent piece from the rest of the tip and preferably a molded piece inserted into a recess in the end face of the tip. The insert may be made of glass, or a ceramic material, or a powdered metal treated by a sintering process. Any desired curvature and variation in curvature can be economically obtained in molding.

Although the invention is particularly advantageous for the construction of cutting tips in which the diverging passage has a longitudinal curvature and a reverse in its curvature, it is not limited to such constructions and can be employed to advantage in making tips that have jet passages that vary in crosssection with a straight taper.

The invention can also be employed in the construction of tips having converging passages for the preheating jet passages. In its broadest as- I pects, therefore, it may be said to be am object of the invention to provide an improved composite tip structure, and method of making such a structure, in which one or more of the jet passages is of progressively changing cross-section along a portion of its length.

Other objects, features, and advantages of the invention will appear or be pointed out, as the.

description proceeds.

In the accompanying drawing, forming apart hereof:

Fig. 1 is a vertical sectional view taken on a diametral plane through a cutting tip embodying this invention;

Fig. 2 is a sectional view on the line 2-2 of I Fig. 1;

The upper end of the body portion has a conical seat of conventional construction.

The preheating jet passages l2 are cylindrical, that is, they are of uniform circular crosssection throughout their length. The cutting jet passage H is of uniform diameter down to a shoulder I that comprises the end of a cylindrical recess in the face of the tip body l0. molded insert it fits the recess and-is cemented into the body portion of the tip in the relation shown in Fig. 1, and forms a terminal portion of a the tip.

The molded insert it has a central passag I! that varies in cross-section with a fair curve and registers with the cutting oxygen passage H and forms the discharge end of the oxygen passage. The passage I! has a diameter at its upper end substantially equal to the diameter of the passage II. From its upper end the passage H decreases in diameter progressively to a throat, at

the section line 2--2, and then increases in diameter to provide the diverging discharge that converts the gas pressure to velocity and prevents lateral expansion of the jet beyond the face of the tip.

The variation in diameter is not at a constant rate in the passage ll shown in Fig. 1. With respect to the axis of the passage H, the longitudinal curvature of the side wall is first concave, then convex at the throat region, and then concave with the radius of curvature increasing until the side wall has a substantially straight taper to the outlet end oi the passage. The concave section of the passage below the throat is a section of progressively decreasing angle of divergence.

Fig. 3 shows a modified form of the invention in which the insert or terminal portion is large enough to include the preheating jet passages. A tip body 20 has a central cutting oxygen passage II and a circle of preheating passages I2. The recess in the face of the tip body 20 is of considerably larger diameter than in the tip body I! of Fig. 1, and a molded insert 23 is cemented into the recess and extends across the ends of the passages 12 where they open through the end wall of the recess.

The central passage ll through the molded insert 23 is the same as the passage through the insert it of Fig. 1 andtherefore designated by the same reference character. There is a circle of preheating jet passages 24 inthe insert 23, and these passages 24 are at the same distance from the axis of the tip as are the passages l2. In order to avoid the necessity of having to register the passages 24 with their corresponding passages i2 in the body portion of the tip, an

annular groove 26 is formed in the top side of the insert 23 in position to serve as a distributing chamber for gas to the passages 24 if they do not register with the passages l2.

It is advantageous for the preheating jet passages to have a slight inward taper toward. their discharge ends, that is, to decrease in diameter towardthe tip face. The passages 24 have such converging side walls, there being no difilculty in obtaining this convergence in a molded piece,

though the taper is in the wrong direction to be made by reaming a metal tip through its face.

In Fig. 4 the recess in the face of the tip body portion is threaded and an insert 28 is threaded into the recess. Cement may be used in addition to the threads to retain the insert 28 in place. When the insert is threaded, an annular recess at the upper end of the preheating jet passages 24 is more important because the preheating jet passages 24 and I2 may not register when the insert 28 has turned into a tight position. Fig. 4 shows an annular groove 29 formed in the metal of the tip body instead of in the insert as in Fig. 3. Either construction can be used, though the annular groove formed in the top of the insert is the-more economical expedient. The insert 28 has a central cutting oxygen passage 30 that differs from the passage ll of Figs. 1-3 in that its changes in cross-section are obtained by tapered side walls tained by molding, the invention is not limited to molded inserts. Even if the inserts or terminal portionsof the tips of this invention are not molded, the fact that they are short pieces, sepaportion having a longitudinally-extending cylin- 2,s4s,9ts'

rate from the tip body when constructed, makes less difllcult the construction of special-shape passages.

Several embodiments of the invention have been illustrated, but changes and modifications can be made, and some features of the invention can be used without others. Terms of orientation are, of course, relative.

I claim: 1. A composite cutting tip comprising a body drical passage through which cutting oxy en may pass and a plurality of smaller, longitudinallyextending passages around the cutting-oxy en passage through which oxygen for preheating flames may pass, a recess in the discharge end of the body portion extending coaxially with the cutting-oxygen passage, said recess terminating at a shoulder where the recess meets the cuttingoxygen passage, an insert secured within said recess and against said shoulder, said insert having a passage extending coaxially with the cutting-oxygen passage and forming a continuation thereof, the passage in the insert varying in cross-section with a fair curve and being restricted intermediate its ends to form a throat, the walls of the passage of the insert inwardly of the throat diverging and having their ends aligning substantially with the walls of the cutting-oxygen passage,and the walls of the passage of the insert outwardly of the throat diverging continuously to the outer end of the insert, the walls of the passage of the insert being inwardly convex at the throat and inwardly concave adjacent the throat at opposite sides thereof, whereby cutting-oxygen discharged from the end of the insert will not expand laterally substantially.

2. A composite cutting tip comprising a body portion having a longitudinally-extending cylindrical passage through which cutting-oxygen may pass, a recess in the discharge end of the body portion extending coaxially with the cutting-oxygen passage, said recess terminating at -a shoulder where the recess meets the cuttingoxygen passage, an insert secured within said recess and against said shoulder, said insert having a passage extending coaxially with the cutting-oxygen passage and forming a continuation thereof, the passage in the insert varying in cross-section with a fair curve and being restricted intermediate its ends to form a throat, the walls of the passage of the insert inwardly of the throat diverging and having their ends aligning substantially with the walls of the cutting-oxygen passage, and the walls of the passage of the insert outwardly of the throat diverging continuously to the outer end of the insert, the walls of the passage of the insert being inwardly convex at the throat and inwardly concave adjacent the throat at opposite sides thereof, whereby cutting-oxygen discharged from the end of the insert will not expand laterally substantially.

JOHN J. CROWE.