US3488003A

US3488003A - Thermochemical piercing apparatus

Info

Publication number: US3488003A
Application number: US703200A
Authority: US
Inventors: John Villoresi
Original assignee: Union Carbide Corp
Current assignee: L-Tec Co
Priority date: 1967-11-22
Filing date: 1967-11-22
Publication date: 1970-01-06
Anticipated expiration: 1987-01-06

Description

r Jams 1970 `AvlL-Lwirl j THERROCHEMIGAL PIERCING APPARATUS original Fileduuly 1s, `196s l Aff JOHN VIgLOR-Es] United States Patent 3,488,003 THERMOCHEMICAL PIERCING APPARATUS John Villoresi, Lincoln Park, NJ., assignor to Union Carbide Corporation, a corporation. of New York Original application July 13, 1965, Ser. No. 471,578. Divided and this application Nov. 22, 1967, Ser.

Int. Cl. F2311 11/40 U.S. Cl. Z39-419.3 3 Claims ABSTRACT F THE DISCLOSURE This application is a divisional application of copending application Ser. No. 471,578, filed July 13, 1965, now abandoned.

This invention relates to thermochemical piercing of ferrous metal, and more particularly to apparatus for starting of said operation on the surface of a workpiece.

The invention provides novel apparatus for starting the thermochemical piercing of cold work, such as steel plate on the upper surface within the boundaries thereof. The apparatus permits rst directing a ring of preheating llames and a central preheating llame perpendicularly against the surface of the cold metal, maintaining all of such flames until such metal is preheated, and then changing the central preheating ame to a stream of piercing oxygen for thermochemical reaction with the so-preheated metal to ignite the center thereof. As a result, starting is about 50% faster, objectionable spatter is virtually eliminated, and cutting of the plate can proceed in any direction from the uniform crater formed thereby.

More specifically the invention provides a nozzle having a central passage for first discharging a mixture of Oxy-fuel gas for sustaining such central preheating flame, and then for discharging such cutting oxygen stream. The nozzle is `also provided with a ring of oxyfuel gas ports for discharging Oxy-fuel gas jets for sustaining such ring of preheating flames. The apparatus includes means for supplying a preheating flame supporting mixture of oxygen gas and fuel gas to such passages, as well as means for supplying cutting oxygen to said nozzle, and valving means for controlling the iiow of such gases to said nozzle. The preheating llame gas mixture is first directed to such central passage as Well as to the surrounding ring of ports. However, tlow of such mixture to such central passage is Shut off when the piercing oxygen stream is turned on. Thus, only oxygen gas flows through the central passage to start the operation within the ring of remaining flames.

In prior cutting nozzles, a plurality of preheat ame gas ports surround a central bore from which a stream of cutting oxygen was discharged. During the initial preheating operation, there was actually a temperature gradient between the annular shaped surface contacted by the preheated flames and the circular area directly under the cutting oxygen stream.

Thus, when the oxygen stream was turned on, the cooler central area contacted was usually below its ignition temperature or at a comparatively lower temperature than the circular area. This caused the oxygen stream to spread out and react with the hotter annular ice area, causing a violent spray of slag. Such spray often caused fouling of the nozzle and was a serious problem especially in multiple torch operations-machine cutting.

The main object of this invention is to provide simple and economical apparatus for faster, cleaner and more reliable initial starting of the operation than was possible in the past.

In the drawings:

FIGURE 1 is a fragmentary enlarged View in longi tudinal section of apparatus illustrating a preferred form of the invention;

FIGURE 2 is a fragmentary view mainly in side elevation of the apparatus; and

FIGURE 3 is a fragmentary view in plan taken on line A-A of FIGURE 2.

As shown in FIGURE 1, radial ports 10 are provided to direct preheating gases into the central bore 12 of the nozzle 14 when the oxygen flow is not on. A flexible sleeve valve in the form of a rubber boot 16 in the central bore, acts as a seal when the high pressure oxygen stream is initiated and blows outwardly to close olf such radial ports. In this manner, the central area against which the oxygen stream will impinge is rapidly preheated to its ignition point Ibefore the stream of cutting oxygen is turned on.

The nozzle 14 is connected to a blowpipe body 18 by a gland 20, and is provided with a ring of preheating gas passages or ports 22, surrounding the central bore or passage 12. The latter is enlarged adjacent the gas inlet end thereof, and the boot or flexible sleeve valve 16 is held in place by tapered spring 24. Oxygen for cutting or piercing is delivered to the inside of valve 16 through a passage 26, and preheating gas is delivered to an Iannular passage 28 in the body 18. Such passages are connected to oxygen and Oxy-fuel gas pipes 30 and 32, respectively, of the blowpipe. The flow of such gases is controlled by an oxygen valve 34 and an Oxy-fuel gas valve 36.

Thus, in starting when the cutting oxygen is not on, the preheating gas flows through all of the nozzle passages and is ignited and flames 38 and 40 are applied to the work such as plate W, FIG. 2. Then, as soon as the latter is preheated by the resulting flames, the oxygen is turned on, and owing through the sleeve valve 16, expands the latter, closing the ports 10, so that only pure oxygen flows through the central -passage 12. This results in quick, clean and fast starting of the operation in the center 42 `of crater 44, FIG. 3. The stream of oxygen then pierces hole 46 through plate W.

What is claimed is:

1. Apparatus for thermochemical piercing of ferrous metal comprising: (l) a nozzle having a central passage for tirst discharging a mixture of Oxy-fuel gas for sustaining such central flame, and then for discharging a pure oxygen stream, and having a ring of Oxy-fuel gas ports for sustaining such ring of preheating ila-mes, (2) means for supplying oxygen gas and fuel gas to such passages, and (3) valving means for controlling the flow of such gases to said nozzle and for first directing fuel gas to such central passage along with oxygen gas to produce such mixture, and then to shut-off the flow of fuel gas to such central passage, whereby only oxygen gas ows through then central passage, wherein said valving means comprises a llexible sleeve valve in the cutting oxygen supply means which closes when the cutting oxygen is turned on, and opens when the cutting oxygen is turned off.

2. Apparatus as defined in claim 1, in which the exible sleeve valve is a rubber boot located in the inlet of the central passage of the nozzle which is provided with radial Oxy-fuel preheating gas ports that are controlled by expansion and contraction of said boot.

3. Apparatus for initially starting the thermochemical working of ferrous metal work, comprising a nozzle having a central gas discharge passage and a ring of gas discharge passages, means for first supplying an Oxy-fuel gas mixture t0 all of such passages for supporting work preheating flames that are applied to the cold work surface, and means for changing only the lcentral preheating ame to a pure oxygen stream to start the operation by igniting the work in the center of the remaining ames as soon as the cold metal is sufciently preheated by all of the flames, wherein said valving means comprises radial preheating gas ports adjacent the gas inlet end of said nozzle, and a exible rubber boot in such end for opening such radial ports when the cutting oxygen flow is 01T, and closing them when such flow is on.

References Cited UNITED STATES PATENTS 1,606,013 1 1/ 1926 Wulif 239-419 1,709,886 4/1929 Smith et al. 239-414 2,188,366 1/1940 Lindstaedt 239-311 0 FREDERICK L. MATTESON, J R., Primary Examiner U.S. C1. X.R. 239-422, 419.5