US1876025A - Drying apparatus and process - Google Patents

Description

Sept. 6, 1932- w. l. SALLEE DRYING APPARATUS AND PROCESS Filed Dec. 3, 1929 5 Sheets-Sheet 1 S 0/ LII/A1124;

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DRYING APPARATUS AND PROCESS Filed Dec. 3, 1929 Sheets-Sheet 3 ATTORNEY Sept. 6, 1932. w. 1. SALLEE 1,876,025

DRYING APPARATUS AND PROCESS Filed Dec. 3, 1929 SSheets-Sheet 4 INVENTOR UM flcwm,

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DRYING APPARATUS AND PROCESS Filed Dec. 5. 1929 5 Sheets-Sheet 5 BY ,mg

INVENTOR ATTORNEY Patented Sept. 6, 1932 UNITED STATES PATENT OFFICE WEBSTER I. SALLEE, OF ROCKY OHIO DRYING APPARATUS AND PROCESS Application filed December 3, 1929. Serial 1T0. 411,279.

zation of heat to free the moisture from the sand, a conveying media to carry away the moisture quickly when separated from the sand, accurate regulation of the heating and conveying media throughout a wide ran e, to eliminate the danger of overheating t e 16 materials and apparatus, efficient handling of the material while being dried. I

An object of my invention is to accomplish this purpose by applying to a continuously progressing and tumbling stream of 20 sand accurately regulated heat evenly distributed along the path of the moving sand stream, and by passing the hot, dry heating and conveying media through the tumbling sand in intimate contact with the individual particles to absorb and carry away the freed moisture and to free and remove any remaining moisture. I

Another object of my invention is to obtain an accurate wide range of regulation of the heating and conveying media by means of independent controls for the fuel, various air supplies, and direction and shape of the heating flame.

Another object is to obtain combustion of the heating media throughout a large port! on of its path so that heat is evenly distributed thus eliminating concentrated heats at'any point with consequent damage to the material or apparatus, and excessive heat loss by radiation.

Another object of my invention is the utilization of a cheap fuel and inexpensive durable apparatus for obtaining these results.

More specific objects include providing passing to the burner and for adjusting the shape and velocity of the forcible air stream surrounding the burner and flame.-

Another specific object is controlling the amount of fuel fed to the burner automatimeans for governing the temperature of fuel cally, depending upon-the heat of the material discharged from the drier.

Other objects and advantages are set forth in my copending application Ser'. No. 429,- 519, filed Feb. 19, 1930, which describes the method of burning fuels which may be accomplished with the burning apparatus herein described; and in my copending application Ser. No. 512,7 66, filed Feb. 2, 1931, which. describes in detail the fuel burning apparatus 00 herein briefly set forth in connection with the drier. i

In carrying out my invention I use an inner drum or 'flue mounted within an outer drum and separated therefrom, formin a assage for the loose materials to be dried.

t has been found that if heat is merely di rected through this inner flue, more or less satisfactory drying may be accomplished. However, to greatly increase the efliciency of 10 such drying, using much greater heats, I cause a return of the hot gases or products of combustion, after passing through the inner drum, along the passage between the drums and through the material.

For economy in fuel consumption, as I stated, I use a low grade fuel and I find that the inner flue, if sufficiently refractory to withstand a direct action of combustion or attackof the flames, correspondingly effects an insulation, and difliculty is encountered in accomplishing even distribution of the heat through the inner drum or flue.

I therefore combine with this inner drum or flue a burner arrangement including a refractory combustion chamber, in which com bustion may be largely or substantially completed, and without waste of fuel, and by forcible air streams, I may govern the combustion for wide variations while directing 99 the products of combustion in the flue. I

An auxiliary air stream may be drawn into the flue for further heat distribution and com- 'pletion of combustion. Still an additional air stream may be united with the returning products of combustion as will be hereinafter described.

.' paratus.

Fig. 2 is an enlarged side elevation of the heating unit for the apparatus shown in ig. 3 is an enlarged longitudinal section through the fuel gun and register of the heating unit shown in Fig. 2.

Fig. 4 is an enlarged transverse view of the heating unit and air supplying means, taken on line 4-4 of Fig. 3.

Fig. 5 is an end elevation of the heating unit.

Fig. 6 is a transverse sectional view of the .drier taken on line 66 of Fig. 1.

Fig. 7 is an end elevation of the discharge end of the drier, a portion being removed for clearness of illustration.

An apparatus found very satisfactory for carrying out the above named object, as well as other objects which will become apparent, is fully described in the following specification, wherein reference is made to the drawings by reference numerals, the same numerals designating the same parts in the various views.

As illustrated, a preferred form of apparatus for this process includes a drier proper consisting of a long substantially and horizontal cylinder or drum sloped slightly from intake end at the right, to'the discharge end at the left of figure. This cylinder 1 is the outer cylinder of the drier and is suitably mounted to revolve upon rollers shown as hearing against supporting rings 5 encircling the drum, the rotation being effected by a gear ring 7 surrounding the drum and meshing with-a pinion 8, on the shaft of a suitable motor 10. Within the cylinder 1 is an inner drum or flue 12 spaced from the outer cylinder and preferablycarried by suitable supporting bolts 14 secured thereto and slidably extending through the cylinder 1, to allow for relative changes due to expansion. Springs, such as 15, surrounding the supporting bolts may be interposed between the cylinder 1 and bolt heads or nuts-16.

At the entrance end of the cylinder 1, i shown a cone-like enlargement or hell 13 spaced from and shaped substantially complementary to the discharge end of heater 20 to be presently described.

The cylinder 12 at the discharge end stops short of the end of the cylinder 1. Mounted on spaced apart supports 17 in the cylinder 1, is a somewhat saucer-shaped baflie or deflecting plate 18, shown as having an inturned perimeter acting to deflect the gas stream from the cylinder 12 outwardly and back between it and the cylinder 1 to a suitable exhaust stack 22. As the cylinder 1 is revolved, its position on the rollers 3, may be maintained by flanges or a roller as shown at4.

The sand or other materials may be fed to cylinder 1, by any suitable means. I prefer to bring it from a. storage bin or any other source to a hopper 30 from which it is discharged onto a belt conveyor indicated at 32 which delivers it onto a deflector or chute 35,

extending into the end of the cylinder 1. The material is caused to pass through the cylinder 1 as it rotates byreason of fins or inwardly projecting plates 36 within the cylinder. As shown these are arranged to carry the sand up as the cylinder revolves and cause it to spread and fall over cylinder 12. By reason of the slope of cylinder 1, sand is advanced slowly by this action to the exit end where it discharges onto a suitable chute such as indicated at 40 which may deliver it to any conveyor, vehicle or receptacle as desired.

My heating unit 20 consists of a primary combustion chamber 21, shown as a metal cylinder lined with a suitable refractory material such as fire brick 50 and contracted at the discharge end to form a cone-like portion 51 and a nozzle-like portion 52. The other end of this combustion chamber is sealed by a suitable plate 54 provided with a peep hole 56, having a central opening adapted to receive the air register 60, in which is mounted a fuel gun 58. I

For this purpose, I may use and have shown an oil gun and register of Letters Patent of the United States No. 1,680,455, making certain modifications therein to meet my requirements.

As shown, the oil gun 58 comprises a cylindrical casing 62, in which a spinner 64 is rotatably mounted in suitable bearings 66. The spinner is provided with an air turbine 68 within the casing. Air under pressure, controlled by a suitable valve 70, is supplied to the gun casing 62 from a fan 72 through a conduit 74. This air passes through the turbine 68 and causes it to rotate the spinner at a very high speed. Oil is fed to the gun 58 under a very pressure from a reservoir through a conduit 75, the amount'being controlled by a valve 76. The conduit 75 extends into the gun casing and joins the hollow shaft of the spinner 64, through which the oil is directed into the inside of the spinner, which gives a high rotary speed to the fuel and throws it out as a cone-like sheet at the end.

Teeth or projections, notshown, on the exit end of the spinner strike the oil as it leaves the cup and impart additional rotary motion thereto, which helps to break the oil into a mist of fine globules.

The air supplied, after passing through the turbine, passes out of the end of the gun, casing around the spinner, and, by means of fins about the inner surface of the casing, is given a rotary motion in a direction oppolow ' ber 21 and opens into the combustion chamber. Withinthe register 60 are a plurality of radial vanes 82 mounted on rock shafts 83. The inner ends of the shafts are pivoted in a collar about the gun casing, and the outer 1 ends extend outside of the register.

over toengage notches in a flange of a ring These outwardly extending ends are bent 84 loosely mounted on the register, so that, when the ring 84 is rotated slightly about the register, the shafts are concurrently rotated about their axes, thus changing the angle of the vanes from approximately a common plane to inward open position.

.An end plate 86, slidable axially of the register on rods 88, provides -a means for regulating the amount of air that can be drawn into the register by the action of the oil gun 68. The air entering the register is given a spiral motion, as it passes through the vanes 82, to control the shape of the flame.

For my purpose, I move the end plate 86 to its withdrawn position and between it and the register install a large sealed even pressure chamber 90 opening into the register 60. Air under pressure is supplied to this even pressure chamber from a power operated fan 92.

A series of shutters 94. operable by a suitable lever 96 are provided near the entrance of the even pressure chamber to control the volume and pressure of air flowing into it. As shown, it is desirable to make this chamber much larger than the register opening order that eddy currents will be broken up and more even pressure created, and consequently, a direct and even flow of air into the register may be obtained. The air thus supplied is given a spiral motion by the radial vanes 82, above described.

A large amount of air is supplied in proportion to the size of the combustion chamber, and consequently, a pressure is built up within the combustion chamber. As a result of this pressure and the spiral motion of the air thus supplied, a rotating column of burning oil and air is formed in the combus- I tion chamber and retains a position in the combustion chamber fairly centrally thereof. This raises the temperature therein to a very high heat, and prevents oil striking the refractor walls of the combustion chamber.

The urning and heated air and oil are driven by this pressure and their initial velocity out of the combustion chamber 21 and into the cylinder or drum 12 of the dryer, into which the nozzle-like portion 52 of the chamber 21 extends.

Combustion of this intermixture of heated and burning oil is completed within the cylinder 12 and may continue throughout a large part of the length of the inner cylinder 12, thus furnishing a large amount of heat very evenly distributed therethrough. This eliminates the necessity for using a high degree of heat in the combustion chamber, witha consequent extremely high temperature at the entrance end of the inner cylinder 12, which might overheat the materials fed onto the inner cylinder 12.

To obtain better control over the distribution of heat and combustion of the mixture, I provide a tertiary air system. On the entrance end of the cylinder 12 is mounted a bell 13, having an inner surface contour, substantially complementary to the cone-like portion 51 and the nozzle-like portion 52 of the combustion chamber 21. e

The combustion chamber is mounted so that it can be moved towards and away from the drum 12, thus increasing or decreasing the size of the opening 102 between the bell and the end of the combustion chamber 21.

Due to the rotary velocity of the burning mixture and the axial velocity at which it enters the cylinder 12, a large quantity of air is drawn into cylinder 12 through the opening 102, the amount being regu ated by changing the size of the opening, as described.

This tends somewhat to insulate the cylinder 12 for a portion adjacent to the heating chamber and absorbs some of the heat issuing therefrom, thus preventing a temperature high enough to damage the drum 12 or the materials. Furthermore, this additional quantity of air permits complete combustion of the large proportion of volatilized oil remaining in the burning stream, thus giving off heat from combustion through a great length of the drum 12. f

The primary, secondary and tertiary air can be regulated independently so that the tertiary air-absorbs only enough heat at the entrance of the drum 12 to obtain the desired lower temperature for the protection of I the cylinder and materials. This heat is not lost but is utilized in raising the temperature of'this volume of air so-that union and combustion with the unburnt oil and gases are more rapid and'obtained while this column of gases are passing through the drum 12.

Cylinder 12' is somewhat shorter than the outer cylinder 1, so that its discharge end is a short distance within the open end of the cylinder 1. Secured to the cylinder 1 by space-apart supports 17 and axially aligned with and placed a short distance beyond the discharge end of the cylinder 12 is a deflecting plate 18 above mentioned This plate is formed to present an inturned center and perimeter, so that the heated or burning gases impinging thereon, as they leave the inner drum at a high velocity, are turned back and passed rapidly between the drum 12 and the cylinder 1 in direct contact with the tumbling materials therein. This deflecting plate is somewhat smaller than the outer cylinder 1, leaving the space 103 between its periphery and the walls of the outer cylinder 1.

Due to the velocity at which these gases are deflected, a suction is created which draws air through the space between the outer cylinder and the deflecting plate. This additional air and the large volume of heated air and gases already furnished, quickly absorb the moisture which has been driven out of the sand, due to its heating by contact with the heated drum 12. Since the sand is continuously tumbling, the surface of each particle is exposed to this draft of heated air, causing1 additional drying, and conveying away t e moisture. Though combustion is usually complete when the heating media have reached the end of the drum 12, if any portion happens to be unburned, this additional air insures complete combustion.

A suitable flue 22 is provided at the end of the outer cylinder 1 adjacent to the heating unit 20, to carry away moisture-laden gases and air and discharge them into the open atmosphere.

It should be noted that the need of a large stack to create a draft is eliminated and that it is not necessary to have a stack sealed about the end of the outer cylinder. As shown, a light metal stack may be provided with a loose-fitting hood extending slightly below the axes of the cylinders and open at the base.

In some cases, it is desirable to direct the flame at an angle to the axis of the drum 12, or parallel to, but offset from such axis. The desired angle or location may be obtained by raising or lowering one or both ends of the combustion chamber 21.

Since this combustion chamber is supported on suitable legs, it may be lifted or lowered or moved axially or transversely of the cylin ders 1 and 12, as desired, by blocking or in any convenient manner. lings for the air and oil conduits are provided for this purpose as shown. Raising or lowering of the ends of the combustion chamber 21 mayalso be accomplished by screws such as designated 110.

It is desirable to control the heat of the material fairly accurately. However, since at different times different amounts of mois-' ture are in the air and in the material, and the temperature of the air and materials may vary greatly, I make my control of heat de pendent upon the temperature of the material as it is discharged from the drier. I may do this by means of a thermostatic switch 111 located atthe discharge end of Suitable flexible coupthermostatic switch operates a mercuroid valve which controls the amount of fuel supplied.

I find it economical and desirable to heat the fuel oil, when starting operation with the burner, to insure atomization of the oil. I accomplish this by means of a heating coil 114. Since it is desirable to use heated oil at all times during burning, I provide several turns of the oil feed conduit about the combustion chamber 21, enclosing the coil thus formed in a suitable housing 112.

As soon as the temperature of the combustion chamber 21 has been raised sufficiently, the heat therefrom preheats the oil as it passes through this coil, and the electric heating coil can be shut off.

' It is apparent from the foregoing descrip tion that I have provided a sand drier which quickly and efflciently dries a large volume of sand under all conditions, and in which the range of use and accuracy of control is of a very high degree.

Experience has effectively dry 2. very much larger tonnage of sand for a given fuel cost than by other devices and systems now in use. The operation of the'device is simple, effective and comparatively inexpensive to install and requires but one attendant.

I claim! 1. A drier comprising an elongated drum, a flue within and spaced from the walls of demonstrated that I may said drum, means to tumble materials to be dried progressively through said drum and onto said flue, a combustion chamber arranged to dischargeinto said flue at one end thereof;v

said chamber being coaxial with said flue, a nozzle at the .discharge end of said chamber for directing products of combustion from said chamber into said flue, said nozzle pro-.

jecting into said flue, the end of said flue being flared around said nozzle and forming an annular passage between said nozzle and said flue, and said combustion chamber being movable toward and away from said flue whereby the size of said annular passage and the amount of air introduced therethrough is controlled, bafile means at the discharge end of the flue to return the products of combustion back between the flue and drum, and means to conduct material to be dried against the flue within said drum at the end adjacent to said combustion chamber.

2. A drier comprising an elongated drum, a

' flue within and spaced from the walls of said ids and air into said chamber, a blower adapted to force air at a pressure above atmosphere into said combustion chamber, and means to regulate the amount of air from said blower, an adjustable air inlet passage between the flue and combustion chamber through which a regulated volume of air may be drawn, baflle means to return said products of combustion back between the flue and drum, and means to conduct'the material to be dried a ainst the flue within the drum at the end a j acent to the combustion chamber.

3. A drying apparatus comprising an elongated drum, a flue within and spaced from the walls of said drum, and means for proa combustion chamber at one end of the drum arranged to discharge into said flue, a fuel gun in said chamber coaxial with said flue and spaced from the discharge end of said chamber, and means to force air and fuel into and through said gun, and means to blow air about said gun and into said chamber, said drum being open at the discharge end, and a baflle arranged'at the end of said flue and in the discharge end of said drum for returning the products of combustion from said flue back between the flue and drum.

4. A drying apparatus comprising an elongated drum, a flue within and spaced from the walls of said drum, and means for progressively tumbling loose materials to be dried over said flue and through said drum, a combustion chamber at one end of the drum arranged to discharge into said flue, a fuel gun in said chamber coaxial with said flue and spaced from the discharge end of said cham ber, and means for forcing air and small into said chamber towards said nozzle for forcing an elongated burning column of flame into said flue and for supplying conveying media for the freed moisture, said flue being.

In testimony whereof, I hereunto aflix my signature.

WEBSTER'I. SALLEE.

particles of fuel into and through said gun,

and means to blow air about said gun and into said chamber, said drum being open at the discharge end, and a baflie arranged at the discharge end of said flue and in said drum for returning the products of combustion from said flue back between the flue and drum, and said last named means including a fan and an even pressure chamber communicating with said fan and said combustion chamber.

5. A drying apparatus comprising an elongated drum and a flue within and spaced from the walls of said drum, and means for progressively tumbling the materials to be dried over said flue and through said drum, a combustion chamber at one end of said drum, said combustion chamber being contracted at one end to form a nozzle coaxial with said combustion chamber and flue and arranged to discharge into said flue through said nozzle,

a fuel gun in said chamber at the end opposite the nozzle arranged to discharge a mixture of small particles of fuel and air into said combustion chamber whereby the mixture is ignited and partially burned, and means to blow a forcible stream of air about said gun and

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