US2541774A - Multiwalled tip shield - Google Patents

Description

Feb. 13, 1951 J. H. MANN, SR 2,541,774

MULTIWALLED TIP SHIELD Filed May 26, 1950 110%, Eflfann J7 INVENTOR BY 1 A 1 4 ATTORNEYS.

Patented Feb. 13, 1 951 UNITED STATES PATENT OFFICE MULTIWALLED TIP SHIELD John H. Man-n, Sr., Rayville, La.

Application May 26, 1950, Serial No. 164,471

3 Claims.

This invention relates to the art of producing carbon black, the invention being a shield for the conventional burner tip.

In my prior application Serial No. 764,958, now abandoned, I have disclosed apparatus in the form of a tip shield having as an essential characteristic its prevention of full combustion of the fuel until such time as the flame resulting from combustion becomes almost wholly productive of carbon black deposit upon the usual collecting surface. The further characteristic is present in the apparatus disclosed in my aforementioned prior application, that during the period in which combustion of the gaseous fuel is prevented, the fuel is pro-heated.

The present invention functions on the same principle as that disclosed in the above specified application. The further characteristic of importance is present in the instant structure, however, that air to be mixed with the fuel for the purpose of causing combustion thereof is preheated, and brought into delayed contact with the fuel under controlled draft conditions.

I achieve this (describing the invention brief- 1y) by mounting upon the conventional burner tip a multi-walled shield that includes an inner imperforate guide that surrounds the burner tip and projects a short distance above .said tip. This in ner guide, which is of cup shape, is in turn surrounded by and spaced from an outer guide that extends higher than the inner guide. The bottom of the outer guide is foraminous so that air is drawn upwardly through the space between the two guides and moved into delayed contact with gaseous fuel after said fuel passes above the top of the inner guide, to cause an intentionally delayed and imperfect combustion. .In one form of the invention heat retaining material is disposed v in said space, and in any event the heat present in said space pre-heats the air.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts, hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

Referring to the drawings Fig. 1 is a transverse section through a burner tip equipped with a shield constructed in accordance with the invention.

Fig. 2 is a top plan view, portions of heat retaining material being removed to show details of construction.

Referring to the drawings in detail, 5 is the conventional fuel supply line this line being provided at spaced intervals with the burner tips 6 each of which is fitted into an opening 1 formed in the supply line 5.

This construction is conventional and does not per se constitute part of the present invention.

In accordance with the invention, the tip 6 serves to support in proper position a multi-walled tip shield which includes an inner guide or baffle 8. This surrounds the burner tip 6, and in the present instance is readily mounted in position by forming a center opening in its otherwise imperioi'ate bottom, with the tapered tip 6 being extended through said center opening 9 of the inner guide 8, and being. wedged into the opening 1 of the supply line.

..As previously noted the bottom of the inner guide 8 is imperforate. The side wall 10 of said inner guide, in this connection, is also imperiorate. By reference to Fig. 1, it will be noted that I extend the side wall [0 of the inner guide to a higher level than the upper or outlet end of the burner tip 6. In practice, I have found it expedient to make the side wall ll] of such a height that it will be at least one half inch above the upper end of the tip, and it can in fact be any distance under two inches above the end of the tip as desired. Different heights of the wall it! of the inner guide will, I have found, produce diiferent results. It is mainly important to note that both the bottom and the wall of the cup-like inner guide are imperforate, and that the wall of said inner guide does rise a distinct and appreciable distance above the upper end of the burner tip.

As to the materials from which the inner guide I!) should be made, I find that to carry out the invention to its best advantage, said inner guide should be formed from some material having a high thermal conductivity and radiation rating.

An outer guide I l is also provided that has an imperforate side wall in the present instance, and a perforated or foraminous bottom !2. In the illustrated example the bottom I2 is of screen mesh material but it could just as well be of the same material as the side wall of the outer guide II, and be simply punched or stamped to provide the openings or perforations in the outer guide.

By reason of this construction, as the flame burns, air will be drawn up through the perforations of the outer guide. .In view of the heat conducted and radiated through the side wall Iii, said air will be heated, and will be kept from mixing with the gaseous fuel emitted from the burner tip '6 until said fuel and air are both disposed above the level of the topof the side wall I'll of the inner guide. The side wall of the outer guide I], meanwhile, is formed to a height distinctly above the top of "the inner guide, and

preferably rises to a height of about one half inch or three quarters of an inch from the collecting surface, not shown, which would be either a channel member or a roller, as is well known in the art.

In the illustrated example I have filled the space between the side walls of the inner and outer guides with heat retaining material I3, this material being packed sufficiently loosely to permit the passage of air therethrough. Thus, the material l3 assists in heating the air during pas sage of the air to the mixing level, said mixing level of air and fuel being that level disposed between the upper edges of the inner and outer guides respectively and clearly illustrated in Fig. 1.

In practice, the inner guide acts in the same manner as the tip shield shown in my prior patent application designated hereinbefore. In other words, the imperforate side wall and bottom wall of the inner guide keeps air from coming into immediate contact with the gaseous fuel, as said fuel flows from the upper end of the burner tip. As a result, combustion is delayed, and does not take place immediately upon issuance of the fuel from the burner tip, as is the case in conventional practice. Rather, the fuel is slightly pre-heated, while the inner guide protects said fuel by keeping cold air from coming in contact therewith. Meanwhile, air is being drawn upwardly through the opening in the perforate bottom I2 of outer guide H, and moving upwardly to the location above the upper end of the inner guide, mixes in a pre-heated state with the fuel. Combustion is thus delayed, and in practice it has been found that this produces a steady flame contacting the collecting surface in a manner to produce the best grade of black. The manner in which the structure operates, in

this regard, helps to cause the carbon to'near its cracking point, but not to burn, thus causing a greater recovery of high grade color black. Combustion is caused at the top of the flame, and heat is then reflected back downwardly into the flame, thus assisting in the function of causing the carbon to crack instead of burn.

Accordingly, by this method I have been able to produce greater quantities of high grade carbon black from less gas, thus creating a saving in both natural gas and other hydro carbons, and leading to a resultant reduction in cost of producing the carbon black.

I believe it is also pertinent to note that it is not essential that the inner and outer guides be cylindrical as shown in the illustrated example of the invention. Success has been obtained with. any shape of guide or bafiie, whether it be cylindrical, square, oblong, or truncated.

It is of further importance to note the plane of the upper edges of the inner and outer guides will be determined by the type of collecting surface. In other words, in the illustrated'ex ample the upper edges of said inner and outer guides or baflies are disposed in flat horizontal planes. This is due to the fact that the illustrated example is one which would be applicable to the channel method of producing carbon black, wherein the collecting surface is the underside of a flat horizontally positioned channel member. If the black is being collected upon a roller, the upper edge of the inner and outer bafiies would conform to the shape of the collecting surface, that is, said upper edges would be arcuately depressed when viewed as in Fig. 1.

What is claimed is:

1. A shield for burner tips used in apparatus for producing carbon black by flame impingement upon a collecting surface, comprising a cup-like inner guide having an opening in its bottom for passage of a burner tip, said opening being proportioned for engagement of said guide by the tip whereby to mount the guide upon the tip, the inner guide surrounding the burner tip and extending to a height above the upper end of said tip, so as to prevent combustion of fuel until said fuel has passed above the upper edge of the inner guide, and an outer guide spaced from and rising to a height higher than the inner guide, the outer guide having perforations for the passage of air upwardly through the space between the guides for mixture of said air and fuel.

2. A shield for burner tips used in apparatus for producing carbon black by flame impingement upon a collecting surface, comprising a cuplike inner guide having a bottom having a single opening for passage of a burner tip, said opening being proportioned for engagement of the guide by the tip whereby to mount the guide upon the tip, said bottom being otherwise imperforate, the inner guide having a side Wall rising to a height a distinct distance above the burner tip enclosed thereby, and at least one outer guide, the outer guide being spaced from and rising to a height higher than the inner guide and having perforations disposed below the plane of the top edge of the inner guide, for

the passage of air upwardly through said perforations and through the space between the guides into the spacedefined between the topedges of the inner and outer guides for mixture with fuel admitted by the burner tip.

3. A shield for burner tips used in apparatus for producing ment upon a cup-like inner upon the tip, said bottom being otherwise im-' perforate, the inner guide having an imperforate side wall, the side wall rising to a plane distinctly above the upper end of theburner tip, thus to shield fuel flowing through the burner tip from mixture with air until said fuel has passed to the area above the upper edge of said guide, an outer guide spaced from and rising to a height distinctly above the top edge of the inner guide, the lower end of the outer guide having perforations for the passage ofair upwardly through the space between the guides and into said area for mixture with the fuel to cause combustion, and heat retaining material disposed in said space between the guides and adapted to pre-heat air passing through said material prior to said combustion.

' JOHN H. MANN, SR.

. REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,339,709 Mohn May 11, 1920 1,401,737 Rumbarger Dec. 27, 1921 1,999,541 Keller Apr. 30, 1935 2,200,826 Johnson May 14, 1940 2,399,591 r Amon Apr. 30, 1946

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