US2552254A

US2552254A - Sand bin and drier

Info

Publication number: US2552254A
Application number: US29062A
Authority: US
Inventors: John P Brunschwyler
Original assignee: Allied Chemical and Dye Corp
Current assignee: Allied Corp
Priority date: 1948-05-25
Filing date: 1948-05-25
Publication date: 1951-05-08
Anticipated expiration: 1968-05-08

Description

May 8, 1951 J. P. BRUNSCHWYLER SAND BIN AND DRIER Filed May 25, 1948 ET SAND BIN INVENTOR. JOHN P. BRUNSCHWYLER ELEVATOR CONVEYOR ATTORNEY.

Patented May 8, 1951 SAND BIN AND DRIER John P. Brunschwyler, Welch, W. Va., assignor to Allied Chemical & Dye Corporation, New York, N. Y., a corporation of New York Application May 25, 1948, Serial No. 29,062

4 Claims.

This invention relates to drying non-absorbent wet granular material and more particularly refers to a new and improved method and apparatus for drying wet sand.

An object of the present invention is to provide a continuous method for economically and effectively drying wet sand.

Another object of the invention is to provide an apparatus of economical construction which is simple and eiiicient in operation.

Further objects and advantages will be apparent from the description and accompanying drawings.

A method for drying wet sand in accordance with the present invention comprises introducing wet sand into the top of a vertical drying chamber. passing the wet sand downwardly countercurrent to and in indirect heat exchange with hot gases, passing the sand through baflles adapted to retard the how of sand, thence passing the sand through a horizontal row of spaced tubes, said spacing between adjacent tubes being sumcient to permit grains of dry sand to pass but without permitting agglomerations of wet sand pass therethrough, passing dry sand into a dry sand bin, discharging the dry sand from said dry sand bin, introducing hot gases into said row of horizontal tubes, thence passing said gases through a conduit upwardly in indirect heat exchange with the downwardly moving mass of wet sand contained in said vertical drying chambar and surrounding said conduit, and withdrawing water vapor evolved from said wet sand through orifices in said conduit.

In accordance with the invention, I provide apparatus involving the combination of a vertical drying chamber adapted to receive wet granular material at its upper end, a dry bin for receiving dry granular material from said vertical drying chamber extending from and disposed beneath said vertical drying chamber, means for efiecting the release of dry material from said dry bin, a horizontal row of tubes having spaces between adjacent tubes sufiicient to permit only the passage of grains of dry material therethrough intermediate said vertical drying chamher and dry bin, baffle means disposed above said tubes adapted to retard the flow of wet material, a source of hot gases external of said vertical chamber and dry a. conduit for conducting said hot gases from said source to said tubes, a ertical extending upwardly through said vertical chamber adapted to receive said hot gases from said tubes, and shielded spaced orifi-ces in said stack for removal of water vapor evolved from said wet material.

In the practice of my invention, I have thoroughly dried wet sand with a material reduction in labor and fuel required by conventional methods. My process and apparatus for drying wet sand also minimizes the exposure hazard occurring in the manual handling of sand.

In the accompanying drawings illustrating my invention:

Figure .1 is a front elevation in partial section of my improved dryer.

Figure 2 is a cross sectional view taken'on line 22 of Figure l in the direction of the arrows.

Referring to Figure 1, wet sand from pit I is lifted by conventional elevator conveyor 2 which may be a bucket elevator with metal links or buckets fastened to the belt or it may be an elevator similar to the .Redler type. From the top of elevator 2, wet sand discharges onto chute 3 into wet sand bin or drying chamber 4. The rate of introduction of wet sand into chamber 4 is preferably regulated to maintain a sand level therein at a short distance below the bottom of chute 3 thereby exposing a greater wet sand surface to indirect heat contact with hot gases in the stack and thus more efliciently utilizing the heat content of the gases.

Wet sand 5 in chamber 4 moving downwardly by gravity becomes heated by the countercurrent flow of hot combustion gases rising in stack 6 causing water in the wet sand to vaporize. Normally, this water vapor would tend to rise against the impediment of packed sand above it and as the water vapor passes upward it would recondense by contact with cooler sand thus preventing the release of Water from the body of sand.

to facilitate the withdrawal of water evolved from the wet sand, I have provided a series of orifices or holes i at intervals in the length. of stack 6. The draft in stack 6 will exert a positive suction in pulling in water vapor through orifices I. Plugging of holes I may be avoided by placing shields 8 in the form of skirts around stack 1 to separate the holes from the surrounding sand.

Near the bottom of chamber 4 are a series of horizontal deflectors or bafiles 9 which may desirably be fabricated from angle iron and placed in an inverted V position. Baflies 9 are spaced to prevent a large amount or large agglomerations of sand falling on the tubes with consequent choking up of passageways between them.

Beneath baffles 9 are two rows of parallel horizontal metal tubes connected to common plenums I I and !2. The upper layer of tubes 13 are widely spaced and the lower layer of tubes It carefully spaced to permit grains of dry, sand to pass through but without permitting agglomerations 3 of wet sand to enter dry sand bin l5. While I prefer to utilize two rows of tubes as just described, I may employ one or three or more rows of tubes providing at least one row of tubes is properly spaced to permit the passage only of grains of dry sand.

The rate of discharge or dry sand from dry bin l5 onto truck l6 may be regulated by turning wheel I! which controls the size of the aperture at the bottom of bin I5.

Heat for drying sand may be obtained from any hot gases from any suitable external source. I prefer to employ the products of combustion from any available fuel such as natural gas and oil generated for example in a hand fired furnace or combustion gas from burning any available carbonaceous fuel in for example a small stoker. Combustion gases generated in furnace 68 are conveyed through insulated flue is into plenum H, thence through parallel tubes [3 and 14 into plenum l2 from which it discharges directly into the bottom of stack 6. If desired, the position of stack 6 in chamber 4 may be shifted to a point more remote from plenum (2, in which event a duct, not illustrated, for conducting the gases from plenum 12 to the bottom of stack 6 would be employed.

Figure 2 illustrates in more detail the relative position of baflies 9, tubes I3 and tubes M. It will be noted that baifles 9 prevent the large mass of sand in chamber 4 from pressing down onto tubes I3 and 14 thereby aiding in the avoidance of jamming the passageways between adjacent tubes. More widely spaced tubes i3 effect a preliminary drying of wet stand and a screening of agglomerations of wet sand. Final drying and screening of the sand is accomplished in closely spaced tubes [4.

The details of construction of the apparatus will of course depend to some extent upon the coarseness of the sand to be dried, its water content, degree of drying desired, etc. I have satisfactorily dried coarse wet sand containing 25% by weight water with tubes 13 having an outside diameter of 4 inches and spaced 8 inches from center to center; tubes 14 having an outside diameter of 4 inches and spaced 4% inches from center to center, and rows of inch diameter holes I around the circumference of stack 6, each row spaced about 70 inches along the length of stack 6.

Although a preferred embodiment of the invention has been disclosed for purposes of illustration, it will be evident that various changes and modifications may be made therein without departing from the scope and spirit of the invention.

I claim:

1. A dryer for drying wet granular material, including in combination a vertical drying chamber adapted to receive wet granular material at its upper end, a row of tubes having spaces between adjacent tubes sufiicient to permit only the passage of grains of dry material therethrough disposed at the bottom of said chamber, a source of hot gas external of said vertical chamber, a conduit for conducting said hot gases from said source to said tubes, a second conduit in communication with the discharge end of said tubes extending upwardly through said vertical chamber, and shielded spaced orifices in said second conduit for removal of vapor evolved from said wet material.

2. A dryer for drying wet granular material, including in combination a vertical drying chamber adapted to receive wet granular material at its upper end, a row of tubes having spaces between adjacent tubes sufiicient to permit only the passage of grains of dry material therethrough disposed at the bottom of said chamber, bafile means disposed above said tubes adapted to retard the flow of wet material, a source of hot gas external of said vertical chamber, a conduit for conducting said hot gases from said source to said tubes, 21. second conduit in communication with the discharge end of said tubes extending upwardly through said vertical chamber, and shielded spaced orifices in said second conduit for removal of vapor evolved from said wet material.

3. A wet sand dryer comprising a vertical drying chamber adapted to receive wet sand at its upper end, a dry bin for receiving dry sand from said vertical drying chamber extending from and disposed beneath said vertical drying chamber, means for effecting the release of dry sand from said dry bin, two super-imposed horizontal rows of parallel metal tubes terminating at both ends in common plenums disposed intermediate the vertical drying chamber and the dry bin, said upper row of tubes being widely spaced and said lower row of tubes narrowly spaced suificient to permit only the passage of grains of dry sand therethrough, a row of spaced baffle members having an inverted V shape parallel to and mounted above said rows of tubes, a vertical stack extending upwardly through said vertical drying chamber and communicating at its bottom end with one of said plenums, shielded spaced orifices in said stack for removal of water vapor evolved from said wet sand, a source of hot combustion gases external of said vertical drying chamber and said dry bin, and a conduit for conducting said hot combustion gases to said other plenum.

4. A dryer for drying wet granular material, including in combination a vertical drying chamber adapted to receive wet granular material at its upper end, rows of tubes disposed near the bottom of said chamber comprising an upper row of tubes widely spaced and a lower row of tubes spaced sufiiciently to permit only the passage of grains of drying material therethrough, a source of hot gas external of said vertical chamber, a conduit for conducting said hot gases from said source to said tubes, a second conduit in communication with the discharge end of said tubes extending upwardly through said vertical chamber, and shielded spaced orifices in said second conduit for removal of vapor evolved from said wet material.

JOHN P. BRUNSCl-IWYLER.

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

UNITED STATES PATENTS Number Name Date 112,118 Buckingham Feb. 28, 1871 363,865 Wales May 31, 1887 652,369 Merriman June 26, 1900 685,336 Leroy et a1. Oct. 29, 1901 695,004 Speer Mar. 11, 1902 731,682 Hillig June 23, 1903 980,387 Yeo Jan. 3, 1911 2,333,089 Burkhardt Nov. 2, 1943