US3478439A - Drum drier improvement - Google Patents

Description

Nov. 18, 1969 R. a. HYLDON 3,478,439

DRUM DRIER IMPROVEMENT Filed April 2, 1968 2 Sheets-Sheet l INVENTOR ROY G. HYLDON AGENT Nov. 18, 1969 e. HYLDON 3,478,439

DRUM DRIER IMPROVEMENT Filed April 2, 1968 2 Sheets-Sheet 2 INVENTOR:

ROY G. HYLDON AGENT drums.

United States Patent 3,478,439 DRUM DRIER IMPROVEMENT Roy G. Hyldon, Crystal Lake, 11]., assignor to The Quaker Oats Company, Chicago, 111., a corporation of New Jersey Filed Apr. 2, 1968, Ser. No. 718,092"

Int. Cl. F26b 13/18 U.S. Cl. 34-114 Claims ABSTRACT OF THE DISCLOSURE An improvement for a rotating, double-drum drier comprising one or more gas discharging means located above the ends of the drums with the gas discharging means being set to direct a gas toward the middle of the drums in order to force a material placed in the trough of the drier away from the ends of. the drier BACKGROUND or THE INVENTION Field of the invention This invention relates to an improvement in a film type, rotary drum concentrating evaporator. More particularly, this invention relates to an improvement in a rotating, double-drum drier.

Description of the prior art Rotating double drum driers have been used for many years in drying slurried materials. These driers consist of two internally heated drums mounted side by side with a narrow gap between them' along their cylindrical surface. The drums are so located with respect to each other that they form a nip along this gap. In operation, the drums are rotated in opposite directions such that the tangential motion of both drums at the point at which they are closest to each other, i.e. at the nip, is in the downward direction. The drums thus" mounted form a trough or channel extending upward from the nip over the curved or cylindrical surface of the drums. Material tobe dried'is slurried or made liquid andplaced'in-the sheet attached to the cylindrical surface of 'each' drum; 1

trough-between the drums. As' the drums are rotated, the -material is forced. into .the nip between the drumsand emerges on' the underneath side'of. the drums as a thin Rotating, double-drum driers are *internally heated, usuallyby steam, to a-temperature' thatwill assure the desired dryingf rate. As the drums, rotate, the heat of the drums dries and/or cooks the thin sheet of the material. The drier sheet is then removed from the drums by a knife blade, rotating wire; brush, for some other device spects has rendered them undesirable for certain" uses. 1

As the slurried material is fed to the trough of the drier, it tends to spread out the full length of the trough. In fact, this spreading out of the material'is desiredin order to assure that the cylindrical surfaces of the drums are fully covered with a thin sheet of the material. Full utilization-of the cylindrical surfaces of the drums is a necessary condition in achieving maximum drying capacity. The desire to have the slurried material extend the full length .of. the trough has heretofore created a problem however.

The problem arises in finding a suitable apparatus or method for retaining the slurried material at substantially the ends of the drums without letting the material spill over the drum cylinder edges or onto the drum ends thus resulting in lost product and unsanitary conditions.

Heretofore, end spillage on rotating, double-drum driers has been solved by one basic method and variations thereof, none of which are wholly acceptable. This method consists of placing an end board on each end of the drier. The end boards are placed flush against the drum ends and extend over the nip of the drier to a height which at least equals, and preferably exceeds, the maximum height the slurried material will reach in the trough. Variations in end board arrangement generally include some type of removable trough insert in which the two longer sides have a shape corresponding to the drum cylinder curvature. These sides are connected on the ends by end boards, and a slit is provided at the bottom of the trough extending the full length of the trough in order that the slurried material may escape into the nip.

The use of end boards to prevent end spillage on rotating, double-drum driers has one inherent defect. The end boards are in close priximity to or are in contact with the heated drums and thus the end boards become heated. Since there is no forced circulation of the slurried material, some of the slurried material remains stagnant against the end boards. When drying certain materials, the heat of the end boards degrades the material until it forms a hard, solid crust. This crust eventually breaks off the end boards and is intermixed with the slurried material resulting in material contaminated by degraded particles. Addition of the hereinbefore described removable trough insert variation of the end boards does not solve this problem, and in fact, it adds to the problem by creating additional heated surfaces Where stagnant material can collect and be degraded to a crust.

The above described formation of a crust on the end boards creates another problem in addition to contamination. Most rotating, double-drum driers are spring loaded, i.e. they have springs which force the drums-together to the desired gap. These springs are provided in order'to prevent a hard object from falling =between-the drums and damaging the cylindrical surfaces of the druni'dr-ie rs. If a hard object falls between the drums, the drums merely separate farther, i.e. the gap betweenithe drums increases, allowing the object to pass between the drums rather than cause damage to the drums'or drum mountings; -When the above described crust falls intothe gap,--the springs allow the drums to separate to let it" passbetween"'the drums. Whilethe' drums are thus separated, avery thick layer of the slurried material is deposited on thedrum. Since the drying rate is regulated to provide'drying' for a thin layer of the slurried-material, the thicker layer is not adequately dry when it reaches the removal means,

i.e. the knife blade. This thick,-wet layeris then deposited in the conveying apparatus usually'resultingin that apparatus becoming plugged and consequentlycztusir'ig disruption in the entire drying process until the 'wet material is removed. It can thus be seen that 'the above described problem .is critical in certain drum drying operations "and is in fact completely undesirable in some drumjdr'ying operations because it renders them practicallyiinoperable. In addition to product contamination} 'certainother problems arisewhen the insert solution isused-to' prevent end spillage. Among these are additional cleaning problems and the problem of additional parts exposed'to considerable wear hence creating a constant need for the replacement of parts.

In view of the foregoing discussion, it may be seen that heretofore there has been a great need for a practical solution to the problem of end spillage in rotating, doubledrum driers. My invention is believed to be the first completely desirable solution to this problem.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improvement in rotating, double-drum driers to prevent product end spillage on the driers.

It is a further object of this invention to provide an improvement in rotating, double-drum driers to prevent product heat degradation-contamination when drying products on such driers.

The objects of this invention are accomplished by placing a gas discharging means in the trough of a ro tat ing, double-drum drier to force the slurried material in the trough away from the ends of the drums and toward the middle portion of the drums.

More particularly, the objects of this invention are accomplished in a drum drier for drying slurried material dropped into the nip of the drier, said drum drier comprising a first rotatable drum and a second rotatable drum, said first rotatable drum having a first rotatable drum first end and a first rotatable drum second end, said second rotatable drum having a second rotatable drum first end and a second rotatable drum second end, said first rotatable drum and said second rotatable drum being spaced apart, juxtaposed, and parallel with said first rotatable drum first end and said second rotatable drum first end being juxtaposed and with said first rotatable drum second end for said second rotatable drum second end being juxtaposed, said first rotatable drum and said second rotatable drum having a first center line and a second center line respectively, said first rotatable drum being symmetrical about said first center line and said second rotatable drum being symmetrical about said second center line, said first center line of said first rotatable drum and said second center line of said second rotatable drum being substantially in the same horizontal plane, said first rotatable drum having a first cylindrical surface and said second rotatable drum having a second cylindrical surface, said first cylindrical surface of said first rotatable drum and said second cylindrical surface of said second rotatable drum forming a nip at the point at which they most nearly meet, and said first cylindrical surface of said first rotatable drum and said second cylindrical surface of said second rotatable drum forming an elongated trough of downwardly decreasing cross-section, said elongated trough of downwardly decreasing crosssection extending upward from said nip and being bound on its lower edge by said nip, said slurried material having a maximum height, said maximum height of said slurried material being above said nip and within said elongated trough of downwardly decreasing cross-section. More particularly, my invention consists of an improvement for the above-described drier, said improvement comprising: a first discharging means for discharging a first gaseous substance, said first discharging means being located above said first rotatable drum first end and said second rotatable drum first end, and said first discharging means being located'in said elongated trough of downwardly 4 said elongated trough of downwardly decreasing crosssection above said nip and below said maximum height of said slurried material and directing said second gaseous substance along said first cylindrical surface of said first rotatable drum and along said second cylindrical surface of said second rotatable drum toward said first rotatable drum first end and said second rotatable drum first end; and a gaseous substance supply means for supplying a compressed gaseous substance to discharging means, said gaseous substance supply means being hermetically joined to said first discharging means and said second discharging means.

The above-mentioned objects as well as other objects of this invention may be more readily seen in View of the disclosure of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The objects of this invention are more fully explained by the claims and further illustrated by the accompanying drawings wherein:

FIGURE 1 is an oblique view of a rotating, doubledru'm drier showing a product being dried thereon and illustrating one gas discharging means at each end of the drier.

FIGURE 2 is an oblique view of one end of a rotating, double-drum drier showing a product being dried thereon and illustrating one gas discharging means at an end of the drier.

FIGURE 3 is an oblique view of one end of a rotating, double-drum drier showing a product being dried thereon and illustrating two gas discharging means used in conjunction with an end board at the end of the drier.

FIGURE 4 is a detailed top view of a rotating, doubledrum drier showing a product being dried thereon and illustrating gas discharging means at each end of the drier being used in conjunction with end boards at each end of the drier.

FIGURE 5 is a detailed top view of a rotating, doubledrum drier showing a product being dried thereon and illustrating gas discharging means at each end of the drier.

FIGURE 6 is a detailed partial side view of the gap side of one drum of a rotating, double-drum drier showing a product being dried thereon and illustrating two gas discharging means at the end of the drier.

FIGURE 7 is a detailed partial side view of the gap side of one drum of a rotating, double-drum drier showing a product being dried thereon and illustrating one gas discharging means at the end of the drier.

FIGURE 8 is a detailed partial side View of the gap side of one end of a rotating, double-drum drier showing a product being dried thereon and showing two gas discharging means being used in conjunction with an end board at the end of the drier.

FIGURE 9 is a detailed partial side view of the gap side of one drum of a rotating, double-drum drier showing' a product being dried thereon and illustrating one gas discharging means being used in conjunction with an end board at the end of the drier.

On the accompanying drawings, I have used the reference numerals 12 and 13 to .refer to rotatable drums. Afxles 14 and 15 are firmly attached to drum 13 and used to support drum, 13. Axles 16 and 17 are firmly atached to drum 12 and used to support drum 12. Drum 13 is heated by a steam inlet pipe 18 which extends into the drum, and the steam condensate is then removed from drum 13 by condensate pipe 19 which extends into the drum and into the condensate collection within the drum. Drum 12 is heated by steam inlet pipe 22 which extends into the drum, and the steam condensate is in turn removed by condensate pipe 23 which extends into the condensate in the drum. The axles 14 and 15 of drum 13 are supported by the housing units 24 and 25 respectively. The housing unit 24 is attached to a spring l0aded:rn0unting 26. The housing unit 25 is supported by a spring loadedmounting 21. The axles 16 and 17 of drum 12 are supported by the housing units 27 and 28 respectively. The housing units 27 and 28 are supported on spring loaded mountings 29 and 32 respectively. The drums 12 and 13 rotate as shown by the arrows in FIG. 1 with their tangential motion at the point at which they most nearly meet being in the downward direction. Product line 33 brings a slurried material 34 to the drum drier. The slurried material 34 falls into the trough 35 between the drums 12 and 13. The rotation of the drums forces the slurried material 34 into the nip 36 between the drums. At this point, the slurried material 34 forms the thin sheets of material 37 and 38 on drums 12 and 13 respectively. The knife blades 39 and 40 remove the thin sheets 37 and 38 respectively from the drums 12 and 13 respectively.

FIGURE 1 and FIGURE 6 show one embodiment '(the preferred embodiment) of my invention. Referring to FIG. 1 and FIG. 6, gaseous supply lines 43 and 44 bring a gaseous substance to the drier where it is discharged through nozzles 45 and 46 respectively. Gaseous supply line 47 brings a gaseous material to the drier where it is discharged through a nozzle 49. It is to be understood that a like gaseous supply line corresponding to gaseous supply line 47, with nozzle 49 thereon, exists at the opposite end of the drier also. The gas from these nozzles is so adjusted as to force the slurried material 34 away from the ends of the drums.

FIGURE 2, FIGURE 5, and FIGURE 7 show an alternate embodiment of this invention. In FIGURES 2, and 7, a single gaseous supply line 53 brings a gaseous substance to the drier where -it is discharged through nozzle 54. While only one end of the drier is shown in FIGS. 2 and 7, the other end is shown in FIG. 5 wherein it is illustrated that the other end of the drier has a like gaseous supply line 53 with nozzle54 thereon. Again, the gaseous substance must be regulated in an amount sufficient to force the slurried material away from the ends of the drum. 1

FIGURE 3 and FIGURE 8 show another embodiment of this invention. In FIG. 3 and FIG. 8, an end board 55 is placed firmly against the ends of the drums 12 and 13 covering the trough 35. Gaseous supply lines 56 and 57 bring gaseous substances to the drier where it is discharged through nozzles 58 and 59 respectively. While only one end of the drieris shown in these illustrations, it may be assumed that the opposite end of the-drier has a like apparatus attached to it. Again the flow rate of the gaseous substance is adjusted 'to'correspond to the material used and the drying rate desired.

FIGURE 4 and FIGURE 9 show still another embodiment of this invention. In FIG. 4 and FIG. 9, the end board 61 has a single gaseous supply line 62 coming to it and extending through it. The gaseous substance is dis charged through nozzle 63. While only one end of the drier is shown in FIG. 9, both ends of the drier are shown in FIG. 5 with the end boards 61, the gaseous supply lines 62, and .the nozzles '63 located thereon. Again, the fiow rate of the gaseous substance is adjusted to correspond to the material used and the drying rate desired.

FIGURE 4am FIGURE 5 show the location of the gaseous supply lines, nozzles, and end boards as seen from a top view. FIG. 4 and FIG. 5 correspond to the apparatus illustrated in FIG. 9 and FIG. 2 respectively. In FIG. 4, the end boards 61 may be seen to be flush against the ends of the drums 12 and 13. The gaseous supply lines 62 may be seen to extend to the end boards 61 and terminate at the nozzle 63. Each of the nozzles herein are located in the trough 35 above one of the ends of the drier. FIG. 5 is a top view of the drum drier without the end boards as is illustrated in FIG. 7 and FIG. 2. In FIG. 5, the gaseous supply lines 53 may be seen to extend up to the drier and terminate at the nozzles 54 which are located in the trough of the drier.

6 PRACTICAL OPERATION In operation, the drums 12 and 13 are rotated as shown with their tangential motion at the point at which they most nearly meet being in the downward direction. The steam inlet pipes 18 and 20 convey steam to the drums 13 and 12 respectively to heat them. As the steam condenses, condensate pipes 19 and 23 remove the condensate from drums 13 and 12 respectively. The rate of rotation of the drum and the temperature to which the drums are heated by the steam depend upon the desired drying rate and allowable drying temperature for the material being dried, and these variables are so adjusted as to optimize the drying rate. The product line 33 brings a slurried material 34 to the drier and discharges the slurried material approximately midway between the ends of the drums. The product line is also set to discharge the slurried material into the trough 35 between the drums. As the slurried material lands in the trough, it tends to spread out the entire length of the trough. As the slurried material approaches the ends of the drums, the flow rate of the gaseous material or gaseous substance that is 'being brought to the drier by the gaseous supply lines (designated by numerals 43, 44, 53, 56, 57, and 62) is adjusted to ara-te sufficient to prevent the slurried material from exceeding the ends of the drums. The flow rate of the gaseous material, however, is adjusted to give .a rate that does not greatly exceed the amount necessary to keep the slurried material away from the ends of the drums. As is illustrated in FIGS. 6, 7, 8, and 9, this adjustment allows the slurried material to completely fill the trough except for a very small portion of the trough at the extreme ends of the drums, and the sheet that is thus formed covers substantially the entire length of the drums allowing maximum utilization of the drying surface of the drums. As the drums rotate, the slurried material is forced into the nip 36 between the two drums. The spacing of the drums at the nip is adjusted to give the desired thickness of the thin sheets of material 37 and 38 which in turn also affects the drying rate. As the slurried material is forced through the nip, it forms the thin sheets 37 and 38 on the drums 12 and 13 respectively. These thin sheets of material adhere to the drums as the drums rotate, and the material is dried and/or cooked to the desired degree. After the thin sheets of material are sufiiciently cooked and dried, they are removed by some suitable means such as knife blades 39 and 40 and allowed to fall in a conveying apparatus (not shown and not claimed as part of this invention) to be further processed and packaged. v

Several embodiments of my invention are illustrated by the enclosed drawings. The number of gaseous supply lines required for each end of the drier is shown to be one or two such pipes for each drier end but may. be taken to be any plurality of pipes or discharging means which will provide a sufiicient amount of gaseous substance to keep the slurried material away from. the ends of the drums. 1

The gaseous material utilized in such an operation can be any gaseous material which is acceptable for use in conjunction with the material being dried. For most operations, air or steam is an acceptable gaseous material,

but other gases, inert and non-inert, can be acceptable for various types of materials. i I 7 Also illustrated by the drawings (FIGS. 3, 4, 8 and 9) are the use of end boards in conjunction with the gaseous supply lines. The use of such end boards may be desired The operation of a drum drier with my improved invention incorporated thereon provides a new and practical solution to the problems hereinbefore discussed at length.

DESCRIPTION OF THE PREFERRED EMBODIMENTS For very viscous slurried materials I prefer to use an embodiment such as is illustrated in FIG. 1. This embodiment consists of two gas inlet pipes at each end of the drier. I prefer that the highest such pipe at each end of the drier be approximately horizontal. I have also found that a nozzle or jet diameter of about A to /2 inch is acceptable for most drying operations. I also prefer that the lower of such gas inlet pipes terminate with the nozzles at an angle somewhere between the horizontal and straight downward, with an angle about midway between the horizontal and straight downward usually being preferred. I have found that a nozzle or jet diameter on this line of about to /8 inch is acceptable for most operations. Because of their easy availability, I usually prefer to use compressed air or super-atmospheric pressure steam as the gaseous substance. While the above discussion details my preferred embodiment, it is to be understood that it does not limit my invention and that my invention is fully defined by the disclosure herein.

It may thus be seen that I have discovered a new and unique invention that substantially advances the art of drum drying of products on rotating, double-drum driers.

My invention has thus provided the first practical solution to a problem that others have heretofore been unable to solve. Therefore, I claim:

1. In a drum drier for drying slurried material dropped into the nip of the drier, said drum drier comprising a first rotatable drum and a second rotatable drum, said first rotatable drum having a first rotatable drum first end and a first rotatable drum second end, said rotatable drum having a second rotatable drum first end and a second rotatable drum second end, said first rotatable drum and said second rotatable drum being spaced apart, juxtaposed, and parallel with said first rotatable drum first end and said second rotatable drum first end being juxtaposed and with said first rotatable drum second end and said second rotatable drum second end being juxtaposed, said first rotatable drum and said second rotatable drum having a first center line and a second center line respectively, said first rotatable drum being symmetrical about said first center line and said second rotatable drum being symmetrical about said second center line, said first center line of said first rotatable drum and said second center r drical surface of said first rotatable drum and said second cylindrical surface of said second rotatable drum forming a nip at the point at which they most nearly meet, and said first cylindrical surface of said first rotatable drum and said second cylindrical surface of said second rotatable drum forming an elongated trough of downwardly decreasing cross-section, said elongated trough of downwardly decreasing cross-section extending upward from said nip and being bound on its lower edge by said nip, said slurried material having a maximum height, said maximum height of said slurried material being above said nip and within said elongated trough of downwardly decreasing cross-section, the improvement comprising: a first discharging means for discharging a first gaseous substance, said first discharging means being located above said first rotatable drum first end and said second rotatable drum first end, and said first discharging means being located in said elongated trough of downwardly decreasing cross-section above said nip and below said maximum height of said slurried material and directing said first gaseous substance along said first cylindrical surface of said first rotatable drum and along said second cylindrical surface of said second rotatable drum toward said first rotatable drum second end and said second rotatable drum second end; a second discharging means for discharging a second gaseous substance, said second discharging means being located above said first rotatable drum second end and said second rotatable drum second end, and said second discharging means being located in said elongated trough of downwardly decreasing cross-section above said nip and below said maximum height of said slurried material and directing said second gaseous substance along said first cylindrical surface of said first rotatable drum and along said second cylindrical surface of said second rotatable drum toward said first rotatable drum first end and said second rotatable drum first end; and a gaseous substance supply means for supplying a compressed gaseous substance to discharging means, said gaseous substance supply means being hermetically joined to said first discharging means and said second discharging means.

2. The drum drier improvement as in claim 1, wherein the first discharging means for discharging a first gaseous substance is an air nozzle, wherein the second discharging means for discharging a second gaseous substance is an air nozzle, and wherein the gaseous substance supply means for supplying a compressed gaseous substance to discharging means is a compressed air supply.

3. The drum drier improvement as in claim 1, wherein the first discharging means for discharging a first gaseous substance is a steam nozzle, wherein the second discharging means for discharging a second gaseous substance is a steam nozzle, and wherein the gaseous substance supply means for supplying a compressed gaseous substance to discharging means is a super-atmospheric pressure steam supply.

4. The drum drier improvement as in claim 1, wherein the first discharging means for discharging a first gaseous substance is a plurality of air nozzles, wherein the second discharging means for discharging a second gaseous substance is a plurality of air. nozzles, and wherein the gaseous substance supply means for supplying a compressed gaseous substance to discharging means is a compressed air supply.

5. The drum drier improvement as in claim 1, wherein the first discharging means for discharging a first gaseous substance is a plurality of steam nozzles, wherein the second discharging means for discharging a second gaseous substance is a plurality of steam nozzles, and wherein the gaseous substance supply means for supplying a compressed gaseous substance to discharging means is a super-atmospheric pressure steam supply.

LLOYD L. KING, Primary Examiner 222 3? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3, 7 39 Dated November- 18, 1969 Inventor(s) Roy G Hyldon It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Eolumn 1 line 51, "drier" should read --dried-. Column 2 line 23, "priximity" should read -proximity-. Column 6 line 2 1,

" 4 4, 53," should read M, 47, 53,--. Column 7 line 37, "said rotatable" should read -said second rotatable.

SiGhED AHJ SEALED FEB 1 71970 an.) M

Wm! I. m m'fllnmhfl' oomluioner of Patents Austin Officer

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