US2028305A - Tube still and furnace construction - Google Patents

Description

I Jan. 21, 1936. I I J. 5. WALLIS ETI'AL 2,023,305

TU BE STILL AND FURNACE CONSTRUCTION Filed 'Aug 51, 1931 2 Sheets-Sheet 1 ATTORN Jan. 21, 1936. J. 5 w 's AL I 2,028,305

TUBE STILL AND FURNACE CONSTRUCTION Filed Aug. 31, 1931 2 Sheets-Sheet 2 R5 Job/7 5. V/a/Ms Patented Jan. 21, 1936 UNITED' STATES PATENT OFFICE TUBE STILL AND FURNACE CONSTRUCTION John S. Wallis and Stephen' B. de BenceyNew York, N. Y., assignors to Al co Products, Incorporated, New York, N. Y., a corporation of. Delaware Application August 31, 1931, Serial No. 560,438

2 Claims.

of radiant heat, the violent heating of the oil inthis bank results in its decomposition and a deposit of carbon. This is particularly true of the upper tubes in the convection bank. It has been found that a temperature of 1400 F. should not be exceeded for the entrant gases into the convection bank.

This necessitates the reduction of the furnace temperature by an excess of air with its consequent loss in efficiency or of the use of a heat absorbing means above the convection bank as described in United States Letters Patent to Primrose, 1,568,182.

In the Primrose patent it was pointed out that the radiation of heat from'that portion of the roof directly over the convection bank raised the temperature of the top rows of the convection bank to such an extent that carbon deposition took place in these tubes, necessitating frequent shut-downs. Primrose solved the problem by the use of heat absorbing elements positioned over the convection bank so that the radiation of heat was cut down due to the fact that it was absorbed. The present invention is directed to another mode of solving the problem.

Then, too, in existing types, the products of combustion sweep the roof tubes resulting in the heating of the roof tubes by convection gases contrary to the intention of the design. Furthermore, a considerable turbulence of the convection gases takes place in the dead corner of the furnace or still existing over the convection bank.

One object of our invention is to increase the efficiency of a tube still by eliminating the necessity for the use of an excess of air or of the employment of an absorbing means and yet prevent the overheating of the convection bank.

Another object of our invention is to provide means for substantially reducing the turbulence of the convection gases.

A further object of our invention is to reduce the contacting of the products of combustion with the roof tubes.

Further objects will appear from the detailed description of our invention appearing below.

Fig. 1 shows a section of a vacuum still embodying my invention.

Fig. 2 is a section of an atmospheric pipe still equipped with my invention.

In general, our invention contemplates increasing the dimension from the top of the bridge Wall to the lowest row of roof tubes. We provide a construction oi. the tile over the convection bank which will give a stream line flow of the gasesv entering it. By inclining: the wall of the still, above the convection bank, at a suitable angle, we are enabled not only to substantially reduce turbulence of the convection gases, but also to reflect the radiant heat back into the firing chamber and away from the top row of the convection tube bank. By placing the convection bank somewhat rearwardly of its usual position, we are enabled to incline the entrant passage of the gases leading into the convection bank and thus obtain a flatter line of flow of the gases from the furnace preventing their flowing up through the roof tubes.

More particularly referring now to the drawings, Fig. 1 shows a section of a vacuum still embodying our invention, having roof tubes I and 2. The upper tubes 2 are of larger diameter than the lower tubes I to permit the vacuum to reach a point in the tubes below which the temperatures are sufiiciently high to bring about a cracking decomposition. This is described in United States Letters Patent to Harnsberger, 1,666,597, and forms no part of our invention.

A bridge wall 3 protects the convection bank tubes 4 from the radiant heat of the furnace chamber 5. Suitable oil burners 6 are provided. It is to be understood, however, that while we have shown an oil fired furnace, pulverized or other fuels may be used. It is to be noted that the convection bank is spaced rearwardly. The inclined wall 1 is placed at an angle such that the radiant heat from the furnace chamber 5 is reflected away from the convection tubes 4 and into the furnace chamber. The converging passage 8 formed by the inclined wall 1 and the inclined top 9 of the bridge wall substantially reduces the turbulence of the gases entering the convection bank and provides a stream line flow. The gases pass down through the convection bank and out through flue connection In, Petroleum oil enters at H and flows up through the convection tubes, thence through the roof tubes to oil outlet I2. I 3 and I 4 are the conventional inlet and outlet from the steam superheater.

In the vacuum still, the flow is two to carry the convection tubes.

throughout. By two to carry we mean that the flow of the oil through the tube still is through a pair of tubes in parallel throughout the furnace.

Fig. 2 represents an atmospheric tube still embodying our invention. Like reference numerals indicate like parts. It is to be noted that the roof tubes l and 2 in the atmospheric still are of the same size. The circulation in the atmospheric still is four to carry in the convection bank and two to carry in the roof bank. The action of the inclined wall 1, the bridge wall 3 and the converging passageway 8 is the same in the atmospheric still as it is in the tube still.

It will be appreciated that our Construction gives a stream line flow of the gases entering the convection bank. Turbulence of the convection gases is substantially reduced. The products of combustion are prohibited from coming in contact with the roof tubes. The tile over the convection bank reflects the heat of radiation back into the furnace, rather than on the top row of It will be seen that we haveaccomplished the objects of our invention.

It will be understood that certain features, and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the appended claims. It is further obvious that various changes may be made in details, within the scope of the claims appearing below without departing from the spirit of our invention and it is, therefore, to be un-- derstood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, what we claim is:--

I. In a tube still of the character described having a boundary wall having a bare interior surface downwardly inclined to the horizontal, a fire chamber, a roof tube bank adapted to be 10 heated mainly by radiant heat, a tube bank adapted to be heated mainly by convection heat, abridge wall interposed between the fire chamber and said last mentioned tube bank said bridge wall having an inclined portion spacedly positioned from 16 said inclined boundary wall and adapted to form a downwardly converging passageway therewith leading from said fire chamber to said tube bank adapted to absorb convection heat.

2. In a tube 'still having a boundary wall hav- 20 ing an inclined portion, a fire chamber having a horizontal roof, a bridge wall, a tube bank positioned between said boundary wall and said bridge wall and having a portion thereof spaced free of the vertical projection of said roof, said bridge wall having an inclined portion defining with the inclined portion of said boundry wall an inclined passageway leading to said tube bank from said fire chamber.

JOHN S. WALLIS. STEPHEN B. m: BENCE.

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