US2706345A - Vertical drier - Google Patents

Description

R. ARNDT VERTICAL DRIER April 19, 1955 2 Sheets-Sheet 1 Filed Jan. 17 1951 INVENTOR Kqymmdflrndi HIS ATTORNEY April 19, 1955 R. ARNDT 2,706,345

VERTICAL DRIER Filed Jan. 17, 1951 Y 2 Sheets-Sheet 2 INVENTOR jlqyrand/lrndi HIS ATTORNEY United States Patent O VERTICAL DRIER Raymond Arndt, Columbus, Nebr. Application January 17, 1951, Serial No. 206,430

Claims. (Cl. 34-65) This invention relates to vertical driers for grain and other comminuted materials and has as an object the provision of an improved drier whereby, by feeding material to be dried past an enclosed space heater in tapered column form, a high degree of efiiciency is obtained.

Another object of the invention is to provide an improved vertical drier wherein a space heater is confined within the drying zone of the drier and the heat generateld thereby is used to both preheat and dry the materia An additional object of the invention is to provide an improved vertical drier utilizing forced warm air as its heating medium, wherein comminuted material is dried and subsequently cooled under controlled conditions of temperature and rate of feed.

A further object of the invention is to provide an improved vertical drier in which comminuted material is treated in the form of a continuous column exposed to drying from different sides and of progressively decreasing thickness within the drying zone, to ensure rapid and thorough drying.

Other objects and advantages of the invention will appear hereinafter in the detailed description, be particularly pointed out in the appended claims and illustrated in the accompanying drawings in which:

Figure 1 is an end elevation view of a preferred form of the drier of the present invention;

Figure 2 is a vertical sectional view, taken along the lines 22 of Figure 1; and

Figure 3 is a vertical sectional view, taken along the lines 3-3 of Figure 2.

Referring now in detail to the drawings in which like reference characters designate like parts, the improved drier is of the vertical type in which gravity is utilized to feed the material to be dried through the several treating zones. The drier is a self-conained unit, comprising a housing 1 of substantially rectangular cross-section and having vertical side and end walls, 2 and 3 respectively, capped by a peaked roof or cover 4. Within the drier, the housing is divided or compartmented vertically into three chambers, compartments or zones, the upper a grain storage chamber 5, the intermediate a drying chamber 6 and the lower a cooling chamber 7. The drier is adapted to be filled or fed with grain or like material from the top through a feed opening or tube 8 in the roof.

Inwardly of the side Walls 2 of the housing, the grain and drying chambers are separated by a partition 9 of inverted V-shape which extends longitudinally of the drier and connects its end walls 3. This partition is preferably made of metal and, sloping downwardly On either side of the vertical center line of the housing, directs the material within the storage chamber 5 towards either side wall 2 of the housing. Another or lower partition 10 separates the drying and cooling chambers, 6 and 7. This partition preferably is substantially fiat and horizontal, connects both side and end walls, 2 and 3, of the housing and desirably is made of material suitable for minimizing heat transfer to the cooling chamber, such as a metal sheet having a heat-reflecting upper surface. Forming the floor of both cooling chamber and housing is a V-shaped bottom wall 11.

Opening into the storage chamber 5, on either side of its sloping floor-forming partition 9 and extending therebelow through the lower partition 10, substantially to the bottom wall 11, are a pair of spaced shafts, chutes, or passages 12 having foraminous or screened sides 13, which extend longitudinally of the drier between its end ice walls 3. Of these sides, the inner are disposed substantially parallel to the side walls 2 of the drier throughout their lengths. The outer of the sides, while connected to the side walls 2, at their upper extremities extend diagonally or obliquely between the adjacent side wall and the lower partition 10 and, downwardly, are inclined towards or converge with the associated of the inner sides. Thereafter, the outer sides are disposed substantially parallel to both the side walls 2 and the inner sides of the passages. There are thus provided a pair of passages which taper or contract to the bottom of the heating chamber due to the convergence of their sides over this zone, this same convergence also spacing the passages from the adjoining of the side walls 2, except at their upper extremities. While the outer of these sides 13 extends to the bottom wall 11 of the housing, the inner side wall of each chamber terminates thereabove to provide, at the lower end of each passage, an inwardly directed opening or outlet 14, flow of material through which is regulated by a bladed or finned feed control roll 15, the rolls of both passages extending longitudinally of the housing and being journaled in the end walls 3. These rolls are driven in a manner to be hereinafter described.

For drying the columns of material in the passages 12, there is mounted in the inner or heat plenum portion of the drying chamber 6, between the tapered portions of the passages, a space heater, heat exchanger or heating unit 16, of the type disclosed in my co-pending application Serial No. 172,155, filed July 5, 1950. Extending longitudinally of the drier and attached to and projecting through one of its end walls 3, the heater is comprised of an outer open-ended tubular shell 17. Within this shell are mounted a combustion tube 18 and a pair of convection tubes 19 arranged in parallel, axially of the shell, with the convection tubes surmounting and supported by the combustion tube. Of the three tubes, the lower or combustion tube is divided axially intermediate its ends by a bulkhead 20 through which projects the exhaust end of a jet burner 21, the latter being supplied fuel through a pipe 22 from a suitable supply tank (not shown) and air for admixture therewith through a variable opening 23 in the outer or fore end of the combustion tube, adjustable by a circular valve 24. Partly consumed in the jet burner 21, the fuel and air mixture completes its combustion in the after or combustion portion of the combustion tube and, deflected by the fixed plate 25 closing the inner end of that tube, flows as hot exhaust gas through connecting tubing 26 to annular recesses 27 in the hollow walls 28 of the convection tubes 19, from whence the gas is exhausted from the drier through a reversely bent exhaust tube 29 and an exhaust stack 30 mounted on the exterior of the adjoining end wall of the drier.

It has'been mentioned that the tubular shell 17 of the heater 16 projects through an end wall of the drier. Within this projecting or outer end portion of the shell, and substantially coaxial therewith, is mounted a multi-bladed fan or propeller 31 by which forced draft of both the air to be warmed by the burner and that entering the opening 23 for combustion purposes is obtained, the fan being driven by a motor 32 mounted on the shell, through drive belts or the like 33. Flowing over the combustion tube 18 and both over and through the convection tubes '19, the reconsumed portion constituting the bulk of the air drawn into the heater by the fan 31 is heated to the desired temperature by the time it enters the drying chamber 6 through the open rear end of the shell. Impelled by the force of the fan, this hot air passes through the tapered portions of the drying conduits from the inner of their foraminous sides 13 into the spaces between their outer sides and the side walls 2 of the drier. Thence, by upwardly and inwardly directed baflles or deflectors 34, which extend the length of the side walls 2, the hot air is redirected through the passages 12 into the inner or plenum portion of the drying chamber and, by the upward pressure exerted by the constantly entering fresh air,

is again driven upwardly across the passages to the side Walls 2. This upward retraversal or recirculation of the air through the passages continues until the air reaches an exhaust opening 35, extending the length of either side wall 2 of the drier, intermediate the vertical limits of the drying chamber 6, through which the air is exhausted to the atmosphere. Some of the air will, of course, be driven into the space within the inverted V-shaped upper partition 9 at the top of the heating chamber. However, as this air loses its heat to the partition, it starts to descend and, becoming mixed with air flowing towards the openings 35, is exhausted from the drier therethrough.

As shown, provision is made for regulation of the temperature of the heating air through controls (not shown), enclosed within a control box 36, which control both the rate of flow of the air through the speed of the fan 31 and the heat generated by the jet burner 21. This control is further supplemented by making the clearance of the exhaust openings 35 regulatable by positioning in each a hinged flap 37, adjustable in angular disposition relative to the side walls 2 of the drier through a handwheel 38, the flaps being hinged to the side walls along the upper edges of the openings and connected to the handwheel 38 through a suitable gear drive 39.

Spaced, except at their upper extremities, from the side walls 2, the drying passages 12 enable the material therein to be traversed from both sides by the drying air. At the same time, the downward taper or contraction of the passages progressively decreases the thickness of the material columns toward the lower end of the drying chamber and, correspondingly, their resistance to traversal by the drying air. Consequently, the volume of air traversing the columns at any level will be in inverse ratio to its distance from the bottom of the drying chamber, ensuring thorough and eflicient drying of the material before it enters the cooling chamber 7. The efficiency of drying is further enhanced by mounting the heat exchange portion of the heating unit entirely Within the drying chamber, between the drying passages, drying thus being obtained both by convection from the currents of warm air and by radiation from the shell of the heater and the exhaust tube 29. This heat serves not only to dry the material in the drying columns, but also to preheat the grain within the storage chamber by transferring heat thereto through the inverted V-shaped upper partition 9.

For cooling the material in the passages 12, once it has been dried, cooling air is forced into the cooling chamber 7 by a fan 40 similar to the fan 31 of the heat exchanger and driven by the same or, as shown, a separate motor 41. The cowling 42, in which the cooling fan 40 is mounted, directing the cooling air into the plenum portion of the cooling chamber 7, between the material passages 12, and the opposite end of the cooling chamber being closed, the resultant pressure forces the air through the passages and the material contained therein to the spaces between the side walls 2 of the drier and the passages and exhausts it from the drier through the same end of the cooling chamber through which it was admitted, that end for this purpose being open.

Regulated in feed through the drying passages 12 by the aforementioned feed rolls 15, thus to control the duration of the treating cycle in both heating and cooling, the dried material on leaving the rolls slides down the V-shaped floor or bottom 11 of the cooling chamber into an outlet trough 43 forming the lower or central extremity of the wall and is driven therealong to the material outlet 44 of the drier by a continuous screw conveyor 45. As best shown in Figure 2, both the discharge conveyor and the feed rolls, While drivable separately, preferably are driven by a single drive unit 46 and are connected through a drive 47 so relating their speeds as to synchronize the flow of material from the rolls and the conveyor and prevent accumulation of material in the bottom of the cooling chamber.

From the above detailed description, it will be apparent that there has been provided an improved drier which is particularly adapted for the drying of grain and like comminuted materials and dries such material efficiently and with dispatch. It should be understood that the described and disclosed embodiment is merely exemplary of the invention and that all modifications are intended to be included which do not depart either from the spirit of the invention or the scope of the appended claims.

Having described my invention, I claim:

1. A drier comprising a housing, a downwardly directed foraminous-sided drying shaft in said housing, said shaft having an inner side disposed substantially parallel to a wall of said housing and an outer side extending diagonally between said wall and a lower extremity of said shaft and converging downwardly toward said inner side, a plurality of vertically spaced baffles intermediate said wall and said outer side of said shaft, and a self-contained space heater in said housing interiorly of and included within vertical limits of said shaft, said heater cooperating with said baffies for forcing drying air repeatedly to traverse said shaft in an upward direction.

2. A vertical drier comprising a housing, a pair of spaced downwardly tapered foraminous-sided shafts mounted in said housing adjacent opposite walls thereof, heating means for said drier consisting of a selfcontained space heater in said housing and included between said shafts, bafiie means intermediate each of said walls and its adjacent shaft and supported on said walls, said baffie means cooperating with said heater for forcing drying air progressively to traverse said shafts in an upward direction, and variable air outlets in said walls intermediate vertical extremities of said shafts.

3. A vertical drier comprising a housing having a drying chamber and a cooling chamber spaced therebelow, a pair of spaced foraminous-sided shafts extending downwardly through said chambers adjacent opposite walls of said housing, an outer side of each of said shafts extending diagonally between vertical limits of said drying chamber and converging with an inner side thereof, heating means in said drying chamber, and cooling means connected to said cooling chamber, said heating and cooling means being disposed intermediate said shafts and adapted to force air to traverse said shafts and be exhausted through said housing exteriorly of said shafts.

4. A vertical drier comprising a housing having a drying chamber and a cooling chamber spaced therebelow, a pair of spaced foraminous-sided shafts extending downwardly through said chambers adjacent opposite walls of said housing, an outer side of each of said shafts connected to and extending diagonally from the adjacent of said opposite walls between vertical limits of said drying chamber and converging with an inner side of said shaft, self-contained heating means in said drying chamber, cooling means connected to said cooling chamber, said heating and cooling means being disposed intermediate said shafts and adapted to force air to traverse said shafts and be exhausted through said housing exteriorly of said shafts, and means adjacent lower ends of said shafts for regulating the feed of material thereto.

5. A vertical drier comprising a housing having vertically spaced drying and cooling chambers, a pair of spaced foraminous-sided shafts extending downwardly through said chambers adjacent opposite walls of said housing, an outer side of each of said shafts connected to and extending diagonally from the adjacent of said opposite walls between vertical limits of said drying chamber and converging with an inner side of said shaft, selfcontained heating means in said drying chamber, cooling means connected to said cooling chamber, said heating and cooling means being disposed intermediate said shafts and adapted to force air to traverse said shafts and be exhausted through said housing exteriorly of said shafts. adjustable means in walls of said housing exteriorly of said shafts for regulating the exhaust of air from said chamber, and means adjacent lower ends of said shafts for regulating the feed of material thereto.

References Cited in the file of this patent UNITED STATES PATENTS 44,512 Buell et al. Oct. 4, 1864 51,169 Gecrnen Nov. 28, 1865 337,948 Greene Mar. 16, 1886 645,366 Mallinson Mar. 13, 1900 1,276,044 Ellis Aug. 20, 1918 1,359,301 Wettig Nov. 16, 1920 1,482,812 Roberts Feb. 5, 1924 2,245,664 Gronert June 17, 1941 FOREIGN PATENTS 597,290 France Aug. 28, 1925

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