US2177404A - Continuous drier for wet granular material - Google Patents

Description

Oct. 24, 1939.

w. H. GOLDEN CONTINUOUS DRIER FOR WET GRANULAR. MATERIAL Original Filed June 24, 1937 INVENTOR. WIN/am H Go/Jen 714;.

A TTORNEYS.

Patented a. 24, 1939 PATENT OFFICE CONTINUOUS DRIER FOR WET GRANULAR MATERIAL 2 William H. Golden, Pittsburgh, Pa.

Application June 24, 1937, Serial Ne. 150.048 Renewed September 19, 1939 9 Claims.

This invention relates to driers for wet granular material such as wet sand and the like, and more particularly to driers adapted for continuous operation. Objects of the invention are ,5 to provide a drier of this nature which will provide a more intimate heat exchange contact between the sand or other material to be dried and the heating medium, and which will have a higher drying capacity than other devices of this nature now in use.

A further object of the invention is to provide a drier which will bring the sand or other material to be dried in contact with heated surfaces in the form of a number of relatively thin films thereby promoting drying speed and permitting the ready escape of water vapor from the material.

A still further object of the invention is to provide a drier which is simple in construction, 20, efiicient in operation, and in which the drying elements consist of a number of superposed trays which are interchangeable and readily replaceable. Further objects will become apparent from the following description and will be 0 pointed out in the claims appended thereto.

With the above and other objects in view, the invention consists in the novel combination and association of parts as will be hereinafter more particularly described, reference being had to the accompanying drawing.

In the drawing;

Fig, 1 is a vertical section showing the assembly of a drier constructed in accordance with the invention.

Figs. 2, 3 and 4 are horizontal sections on the lines XX, YY, and ZZ, respectively, of Fig. 1, looking in the direction of the arrows. Fig. 5 is a detail section taken on-the line 55 of Fig. 3 showing one of the drying trays.

.Referring to Fig. 1, the drier includes a furnace 5, having a central flue 2, and plurality of spaced side flues 3, the whole constituting an assemblyfor the generation and transmission of heat. The furnace I may be a coal burner as shown, but it may be readily adapted for the combustion of wood, oil, or gas without departing. from the scope of the invention. In the modification shown the furnace consists of a supporting base 4, an ash box 5, provided with an opening 6 for the removal of ashes and preferably fitted in the usual manner with an ash door having an air register and a top flange 1 supporting a grate 8. The fire box consists of a cylindrical side wall 9, which may be lined with insulating brick and which is provided with an outwardly extending flange ID at the lower edge thereof for a purpose which will subsequently be described. A firing door H is fitted into the side wall in the usual manner but is fitted with 60 a firing collar l2 extending some distance away from the furnace to keep the sand or other material to be dried out of the fire box.

The furnace I, whether of the coal, oil, or gas fired type is provided with a fire box dome or top l3 which is seated on the cylindrical side 5 wall and is provided with the central flue 2 and the side flues 3, which are preferably four in number, spaced at angles of 90. In the modification shown, the dome I 3 is a separate casting, and is fitted with flanges M to make a gastight fit with the side wall 9 and the flues are cast integral therewith. The central flue 2 is relatively short and has a level upper edge, while the side flues 3 are beveled toward the central flue and provided with notches 4 for a purpose which will subsequently be described.

The drying trays which are mounted above the furnace in superposed relation constitute one of the features of the invention, since they operate to bring the sand or other material to be dried into close contact with the flues containing the hot gases from the furnace. Each tray consists -'as shown in Fig. 5 of an inverted frustro-conical bell 15 which is preferably of cast metal, the bell having a peripheral zone consisting of a heat conducting flange I6 with openings I! therein and a central zone, which is also preferably provided with additional openings 18 and which has a plurality of vertical flue pipe sections I9 cast integral therewith. In the top of each flue pipe section I!) is a small vent 2| which is of the order of 0.5 sq. in. in cross-section and which provides communication between the interior of the flue and the spaces between the drying trays. Similar vents may be provided in the central flue pipe sections 20, although they are not shown on the drawing.

Reference to Fig. l of the drawing will show that the various sections are supported upon each other when the drier is assembled so that any section may be removed and a new one replaced with a minimum of time and effort. Similarly, the drier may be provided with any number of drying trays to suit the requirements of any given sand or other material to be dried and the extent to which the moisture must be removed.

It will be noted that the peripheral openings I! are larger than the central openings l8, thereby promoting the continuous movement of the sand or other material from the periphery of the trays to the central zone and causing it to be heated in thin films which promotes a ready escape of the steam or water vapor between the trays and through the vents 2| in the flue pipe sections 19.

The various drying tray sections are covered by a top flue piece 25, which is in the form of a spider seated on the top flue pipe sections as at 26 and having beveled edges to correspond there- With. The arms of the spider which constitute continuations of the flue pipe sections connect them with a stack 21, preferably provided with a damper 28, and thus serve to collect all the hot gases from the furnace l.

The entire drier assembly is surrounded by a vertical shell 30 which is supported by a perforated ring 3| seated on the flange II] at the bottom of the furnace wall. This shell serves to retain the sand and conduct the dried sand downwardly around the wall 9 of the fire box and through openings 32 in the ring v3! and away from the drier.

The operation of my improved drier will be apparent from the above description. Sand is shoveled into the top of the drier, and is distributed over the top bell by the arms of the spider 25. The sand travels by gravity over the surface of the top drying tray and falls through the openings 17 and 8 onto the second tray in the form of relatively thin streams, the moisture,

being removed by the heat of the tray and of the flues i9 and 26 around which the sand is caused to pass. The sand drops by gravity from tray to tray, losing moisture in each passage over the hot metal. The openings H and 18 are preferably made smaller in the lower trays than are the corresponding openings in the upper trays, and are sized so that the bells or trays do not completely fill with sand. The openings 2!, being at the tops of the flue sections always remain uncovered so that moisture evaporated from the sand will pass into the combustion gas flues and will be carried away with the combustion gases therein. By reason of the inclined surfaces of the trays and the heat conducting capacity of the flanges IE, only dry sand can come into contact with the top or side walls of the furnace l, and so these parts are protected from warping or cracking.

From the above it will be seen that the invention provides a drier which is both simple and efficient in operation. I have found by actual comparison that the drier of the present invention will remove the same amount of moisture from more sand than will other driers of equal size that are now on the market.

What I claim is:

1. A continuous drier for wet granular material comprising in combination a plurality of superposed, inverted frustro-conical drying trays, openings near the periphery of each tray to permit the gradual downward passage of the granular material from tray to tray, and a vertical heating conduit passing through the central zones of said trays.

2. A continuous drier for wet granular material comprising in combination a plurality of superposed, inverted frustro-conical drying trays having graduated openings therein of a size to permit the gradual downward passage of the granular material from tray to tray, a shell surrounding said trays, and a plurality of vertical heating conduits passing through the central zones of said trays.

3. A continuous drier for wet granular material comprising in combination a plurality of superposed, inverted frustro-conical drying trays, openings near the periphery of each tray to permit the gradual downward passage of the granular material from tray to tray, a vertical flue for hot gases passing through the central zones of said trays, and vents in said flue be tween each pair of trays to permit water vapor evolved from the granular material to pass into 4. A continuous drier for wet granular material comprising in combination a plurality of superposed, inverted frustro-conical drying trays having graduated openings therein 01' a size to permit the gradual downward passage of the granular material from tray to tray, a shell surrounding said trays, a plurality of vertical flues for hot gases passing through the central zones of said trays, and vents in said flues between each pair of trays to permit Water vapor evolved from the granular material to pass into the flue.

5. As an article of manufacture, a drying tray comprising an inverted frustro-conical bell of cast metal, said bell having a peripheral zone consisting of an apertured heat-conducting flange and a central zone having openings therein and a plurality of vertical flue pipe sections cast integral therewith.

6. As an article of manufacture, a drying tray consisting of an inverted frustro-conical bell of cast metal, said bellhaving a peripheral zone consisting of a heat conducting flange with openings therein and a central zone having openings therein and a plurality of vertical flue pipe sections cast integral therewith, each pipe section having a notched upper edge that terminates in a plane parallel to the plane of the bell at its base.

7. A continuous drier for wet granular material comprising a plurality of drying trays, each tray comprisingan inverted frustro-conical bell of cast metal havinga peripheral zone consisting of a heat conducting flange with openlugs therein to'permit the passage of the granular material and a central zone having openings therein and a plurality of vertical fluepipe sections surrounding said openings, each pipe sec tion having a notched upper edge that terminates in a plane parallel to the plane of the bell at its base and forms a supporting seat for the tray above it, and a top flue piece comprising a spider seating on the top flue pipe sections and connecting them with a stack.

8. A continuous drier for wet granular material comprising in combination a furnace for the'generation of hot gases, a, plurality of vertical lines in the top of said furnace, a plurality of superposed, inverted frustro-conical drying trays surrounding said flues, openings near the periphery of each tray of a size to permit the gradual downward passage of the granular material from tray to tray, vents in said flues between said drying trays, and a spider seating on the tops of said flues and connecting them with a stack.

9. A continuous drier for wet granular material comprising in combination a furnace including a cylindrical side wall, having an outwardly extending flange at the bottom thereof, a perforated ring seated on said flange, a cylindrical shell supported on said ring, a top for the furnace seated on the cylindrical side wall thereof and provided with a central flue and a plurality of spaced side flues having notched upper edges which are beveled toward the central flue, a plurality of drying trays comprising inverted frustro-conical bells seated upon said flues, each bell having graduated openings therein and notched flue sections in alignment with the flue sections of the furnace top, and a collecting spider surmounting the top flue sections and connecting them with a stack.

WILLIAM H. GOLDEN.

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