US2513767A - Gaseous mixture - Google Patents

Description

Patented July 4, 1950 Gaseous Mlxrunn Samuel n. White, DetroigMich. I

' No blame. mutation July 15, 1947, serial No. 761,155. In Great Britain April 24, 1947 1 Claim.

This invention relates to gaseous fuel mixtures and more particularly to such fuel mixtures that have a high calorific value and a low ignition point.

Fuel mixtures of this type are in demand for use in metallurgical and other industrial operations in which an intense local heat is required, as for instance, in cutting metals, hardening and annealing, scarfing, melting and welding metals and the working of lead, hard glass and silica. For these purposes, the oxy-acetylene and oxy-hydrogen fiames have been widely used but both are comparatively expensive, and in the case of acetylene, because of high carbon content and critical nature of the flame, unless great precautions in use are observed, it is liable to be dangerous and costly and work may be spoiled.

It is an object of the present invention to provide a cheap gas mixture by raising the calorific value and lowering the ignition point of the ordinary fuel gas, such as coal gas and natural (petroleum) gas supplied for general public use which will be referred to hereinafter as city gas.

The gas mixture may be made in the first instance and compressed in cylinders and used direct from the cylinders to the burner. Alternatively, the supplementary gaseous material required to raise the calorific value and lower the ignition point of the city gas may be obtained from material compressed in cylinders and supplied from the cylinder to the citys gas in pipe lines by means of suitable flow meters.

Various proposals with the above object in view have been made hitherto. There are, however, difiiculties involved in making a gas mixture as above described from, for example, ordinary city gas by making additions to raise the calorific value and lower the ignition point and produce a gas which is comparable for the purposes above described with acetylene. Suitable materials for addition are necessarily of an easily condensable character, such as the higher hydrocarbons and gas mixtures supplied in the usual city mains consist mainly of the more permanent gases, of which hydrogen, carbon monoxide and methane are examples. When substances are added with a view to increase the calorific value and lower the ignition point, in many cases such substances condense under pressure in the cylinders, and when the cylinder is opened to supply a burner, direct or through pipe lines, imperfect diffusion of the constituent gases may occur and a homogeneous gas, such as acetylene will not be supmoving stream of gas meets the oxygen supply there may be also imperfect diffusion with consequent deleterious effects upon the intensity of the flame and its resulting temperature.

It has now been found possible by proper selection of the added material and the proportions in which it is used to produce a gas mixture which, whether used from a cylinder or formed in the pipe line by introducing compressed material from a cylinder, will give a homogeneous mixture at the point at which ignition occurs and which may be used with oxygen in the same way as acetylene and produce comparable results and in some respects even improved results.

According to the present invention a gaseous fuel mixture consists in city gas and petroleum ether, the proportion of the latter being 5-10 lbs. for every 1,000 cubic feet at F. and at atmospheric pressure of the city gas. The petroleum ether referred to is the petroleum fraction having boiling point ranges from approximately 40 C. to 60 C. at atmospheric pressure, such, for example, as benzin.

Other petroleum ethers with higher boiling points may be used in the proportions stated provided means are employed to vaporize the material sufiiciently for proper diffusion with the citys gas before ignition occurs.

The petroleum ether lowers the ignition point of the gas and raises the calorific value, retards flame propogation and greatly intensifies the fiame thereby imparting a greater fiame temperature than is possible with city gas alone. Thes properties enable the gas mixture to be used in like manner to acetylene for the purposes hereinbefore enumerated and is particularly effective for use in aluminum welding, burning of lead and like purposes for which pure hydrogen has hitherto been used. The gaseous fuel may be distributed through a pipe line under the necessary pressure, depending primarily upon the work for which it is required.

Although the minimum proportions abovementioned are effective for the purposes stated, the maximum proportions are desirable for all uses on thick or rusty metals, for blowing holes or bevel cutting and the like. The proportions will also be chosen within the specified range according to the calorific value of the city gas supplied.

Although a certain specific embodiment of the invention has been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be replied to the burner. Moreover, when the rapidly 55 stricted except insofar as is necessitated by the REFERENCES CITED The following references are of record in the file of this patent: l

UNITED STATES PATENTS Number Name Date 1,565,933 Harris Dec. 15, 1925 1,584,291 Harris May 11, 1926 1,596,729 Harris Aug. 17, 1926 1,637,187 Harris July 26, 1927 2,411,769 White Nov. 26, 1946 OTHER "The Science of Petroleum, Dunstan, editor, Qxford University Press, London 1938, vol. I, pages 7 and 12.

*Hackhs Chemical Dictionary," by Hackh, 2nd

edition, published by Blakistons Son Inc., Philadelnhia, 1937, page 69s. 7