US1943859A - Gas burner - Google Patents

Description

Jan. 16, E H HSHER I I 1,943,859-

GAS BURNER Filed April 19, 1933 WITNESSES INVENTOR W. 22w; 1/ $4756, .Z/n. 34w q 5 a a/410* 40:

i; MM;

Patented Jan. 16, 1934 4 UNITED STATES PATENT OFFICE GAS BURNER Application April 19, 1933.

3 Claims.

This invention relates to gas burners, and more especially to laboratory burners of the so-called Bunsen type.

Various embodiments of the Bunsen labora- 5 tory burner are made which operate satisfactorily with manufactured gas to produce flames of different character, e. g., oxidizing or reducing.

Natural gas, however, requires larger amounts of air for combustion than manufactured gas, and in consequence the ordinary forms of Bunsen burner do not operate satisfactorily with it. A

common experience is that the flame is extinguished readily by extraneous air currents, particularly when the air supply is regulated to give an oxidizing flame.

Various means have been proposed for adapting such burners to use with natural gas, but so far as I am aware all of them have been subject to disadvantages of one kind or another. For instance, some of these means are not practically operative, while others are not mechanically satisfactory or are expensive to make.

It is among the objects of this invention to provide a Bunsen type laboratory gas burner with means adapting it to satisfactory use with natural gas, which means are of simple and inexpensive construction, may be embodied as an integral part of a burner or supplied as an accessory for use with ordinary laboratory burners, and which in the preferred embodiment eliminate back firing.

The invention may be described in connection with the accompanying drawing, which represents its preferred embodiment, and in which Fig. 1 is a vertical elevation of an ordinary type of burner provided with a tip embodying the invention; Fig. 2 a longitudinal sectional view, on an enlarged scale, through the tip shown in Fig. 1, taken on line II-II thereof; and Fig. 3 a plan view of the tip shown in Fig. 2.

The invention contemplates Bunsen type laboratory burners including a burner barrel, or tube, provided at the lower end with means for introducing a mixture of gas and air, and having I its upper portion of substantially uniform diameter. In accordance with the invention the upper end of the barrel is provided with a tubular tip having a bore whose lower portion is of substantially the same diameter as the bore of the barrel, the upper portion of the bore being of reduced diameter. Surrounding the tip bore is an annular chamber of increasing volume upwardly, the lower portion of the chamber communicating with the lower portion of the tip bore by perforations formed in its wall. The lower end of the chamber is closed, and the upper end is defined by Serial No. 666,855

a wall provided with a plurality of perforations surrounding the tip.

In the use of a burner tipped in accordance with the invention a slight back pressure is created in the lower portion of the tip in consequence of the reduction in bore diameter at the upper end. This causes a small amount of the gas-air mixture flowing through the burner to expand through the perforations into the annular chamber, and this lay-passed gas further expands within the annular chamber by reason of its construction, so that the gas escaping through the perforations in the top of the chamber provides a low velocity pilot flame surrounding the main, high velocity mixture of gas and air flowing through the tip bore. This pilot flame successfully maintains the main flame ignited under all conditions of use with natural gas.

The invention may be described more in detail with reference to the drawing. Fig. 1 shows a conventional type of laboratory Bunsen burner comprising a base 1 supporting a burner barrel 2 provided at its lower end with a nipple 3 for connection to a source of gas and leading to a nozzle, not shown, within the barrel. The lower end of the barrel is surrounded by a rotatable sleeve 4 having perforations 5 adapted to be brought into regulated register with perforation 6 in the barrel, so as to control the amount of air drawn into the barrel by the flow of gas through the nozzle. Various forms of gas nozzle and air-regulating means other than those shown are known in the art, the form shown being conventionally represented for purposes of illustration.

The burner shown in Fig. 1 is of a type commonly used satisfactorily with manufactured gas. The upper end of barrel 2, which is of substantially uniform diameter, is provided with a removable tip 7 which in accordance with the invention comprises a tubular member 8 having a central bore having lower, intermediate and upper portions of successively progressively reduced diameter. Lower portion 9 of the bore is of substantially the outer diameter of barrel 2, as shown in Fig. 2, so as to neatly lit the top of 100 barrel 2. The diameter of intermediate portion 10 is reduced so that it is substantially the same as the bore of barrel 2, and upper portion 11 of the tip bore is of still further reduced diameter. portions of the bore is an annular expansion chamber which is connected near its bottom to intermediate portion 10 of the bore by perforations 12 formed in its wall.

These tips may be, and preferably are, made Surrounding the intermediate and upper v sizes smaller.

by machining a brass, or other suitable metal, rod or tube of appropriate diameter. Most suitably the annular expansion chamber is formed by cutting recesses 13 and 14 to provide recesses annularly surrounding the intermediate and upper portions of the bore. Recess 14 is of greater volume than recess 13 and it is cut to provide a top flange 15. Preferably the recesses are cut to leave an intermediate flange l6 separating them approximately in the plane between intermediate bore portion 10 and upper portion 11, for a purpose presently to be described. Flanges 15 and 16 are drilled to provide perforations 17 and 18, respectively, for flow of gas through and out from the chamber.

The annular chamber is closed by a side wall casing member comprising a section of tubing 19 whose inner diameter is such as to snugly engage flanges 15 and 16, to prevent leakage of gas between the flanges and the casing. The lower end of casing 19 is rolled or crimped into a groove in the body of the tip, as indicated at 20, Fig. 2, to close the lower end of the chamber.

In the use of this burner tip a mixture of gas and air flows upwardly through the burner barrel and emerges into the intermediate portion of the tip, flowing thence through the upper portion of the tip and leaving the tip through upper bore portion 11. The reduction in diameter of the upper portion of the tip creates a slight back pressure in the intermediate portion, which causes a small amount of gas to expand through perforations 12 into the bottom portion of the annular chamber, from whence it flows upwardly through the chamber, expanding progressively,

so that it emerges through perforations 1'? in a plurality of low velocity jets which form a pilot flame surrounding the bore. This ring-lil e pilot flame remains lighted, because due to its low ver locity it is not affected by air currents, so that it maintains the main flame issuing from the upper portion 11 of the tip bore ignited despite any tendency for it to be extinguished.

A particular feature of the invention resides in making perforations 18 somewhat smaller than perforations 17, which eliminates any tendency to back-fire through the lower portion of the annular chamber into the burner barrel, to cause base burning. For example, with a tip having a an outside diameter of inch at its upper end,

and having upper bore portion 11 of g t inch diameter, perforations 17 may be made with a No. 45 twist drill, the holes being spaced 60 apart. Perforations 18 may be made with a drill a few Perforations 12 may be relatively large, for example, No. 28 drill size, only two of them being required, and because of the back pressure in the bore they need not be inclined upwardly or provided with gas-deflecting baffles, but

i :may be horizontal, as shown.

stood that, if desired, the tip can be embodied as an integral part of a burner, for example in the case of burners intended for use with natural gas alone.

According to the provisions of the patent statutes, I have explained the principle and construc tion of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A detachable adapter tip for a laboratory gas burner comprising a tubular member having its bore composed of lower, intermediate and upper portions of successively reduced diameter upwardly from the base of the tip, the diameters of said lower and intermediate portions being, respectively, substantially those of the exterior and interior diameters of the burner barrel to which the tip is applied, an expansion chamber closed at its lower end surrounding said intermediate and upper portions, the lower end of the chamber being smaller than the upper end and being connected to said intermediate bore portion by perforations through the wall, and the top of said expansion chamber being provided With a top wall having a plurality of perforations surrounding said upper bore portion.

2. A detachable burner tip for a laboratory gas burner comprising a tubular member having its. bore composed of lower, intermediate and upper portions of successively reduced diameter up-,

intermediate bore portion by perforations through i the wall, and the upper portion of said expansion chamber being provided with a top wall having a plurality of perforations surrounding the upper end of the tip.

3. A detachable adapter tip for a laboratory gas burner comprising a tubular metallic sleeve having inwardly projecting shoulders forming a bore comprising, respectively, a lower portion adapted to neatly receive the top of the burner barrel, an intermediate portion of substantially the interior diameter of the barrel, and an upper portion of further reduced diameter, the exterior of the sleeve being recessed peripherally to provide a top flange and a second flange disposed approximately in a plane between said upper and intermediate bore portions, and a casing member disposed in contact with said flanges and forming therewith a lower chamber annular to said intermediate portion and upper chamber of greater volume annular to said upper bore portion, said top flange being provided with perforations surrounding the tip, and said second flange being provided with perforations smaller than those in said top flange, and the wall of said intermediate bore portion being perforated for flow of gas into said lower chamber under back pressure in said intermediate bore portion caused by said upper bore portion.

EDWIN H. FISHER.

Images