US2143019A - Drum drier - Google Patents

Description

Jan. 10, 1939. C. 0, LAVETT 2,143,019

DRUM DRIER Filed 001;. l5, 1935 lNvENToR a a ATTORNEGYsoDg Patented Jan. 1o, 193s 2,143,019

UNITED STATES PATENT OFFICE DRUM DRIEB charles o. raven, Buffalo, N. Y., minuia Buffalo Foundry & Machine Co., Builalo, N. Y., a corporation oi' New York Application October 15, 1935, Serial No. 45,092

4 Claims. (Cl. 159-11) The invention relates to an atmospheric drum drier and more particularly to a drum drier for handling liquid materials which tend to become viscous and pasty and dilcult to handle and remove when handled on drum driers of conventional types. More particularly the drier forming the subject of this invention is designed to handle such materials as whey, following the process shown and described in my copending application for patent, Ser. No. 152,616, led July 8, 1937.

It is the object ot the invention to provide a drum drier which operates, in two stages, to eliminate moisture from a liquid solution and convert it into a solid state in a short space of time and which is of high capacity and continuous operation thereby to permit of low cost operation and as a continuous process.

In the accompanying drawing:

Fig. 1 is a side elevation of a drum drier embodying my invention and showing the same discharging into a grinder and bagger.

Fig. 2 is a vertical transverse section, taken on line 2 2, Fig. -1.

In the atmospheric drum drier shown the solution is partially dried between an upper pair of drums and 6 and then further dried between a lower set of drums 1 and 8. All of the drums are jourualed in the usual end` heads 9 and I0 of the supporting frame and the drums of each set are driven in opposite directions by means of gears Il and I2, the speed of each set depending on conditions. Steam is admitted to each of the drums and the condensate removed therefrom by means of steam and condensate connections I3 and I4 extending through the spindles of the drums. The drums of the upper set are set close together and are provided at opposite ends with end boards I5 which are held against the ends of the drums in any suitable manner and form a reservoir I6 between the drums. Similarly, the lower pair of drums are provided at opposite ends with end boards I1 arranged against the ends of the lower pair of drums and forming a receiving space I8 between the lower pair of drums, the spacing between them being adjustable, by means of any well-known adjustment such as by the usual movable bearings and screw adjustments indicated at 29.

The upper pair of drums is driven by a pinion I 9 in the opposite direction from the drums of a conventional double drum drier, i. e. the drums 5 and 6 travel upwardly at their point of closest approach. The lower drums 1 and 8 are driven by a pinion in the opposite direction from the upper set of drums, i. e. they travel downwardly at their point o! closest approach.

The vapors generated during drying are carried away by means of a hood 2| and the solution is discharged from a pipe 22 into the reser- 5 voir I6 between the upper set of drums 5 and 6 and the end boards I5 at the ends of these drums.

An essential feature of the present invention resides in the rotation of the upper drums 5 and 6 upwards at their point of closest approach and 10 in the rotation of the lower set oi drums 1 and 8 downward at their point of closest approach. By this means the solution is held in the reservoir I6, .and is maintained in a liquid condition and at its honing point. The quantity of squid 1n l5 reservoir I6 is held lor a time, which is sufficient to raise this liquid to the boiling point but not long enough to concentrate the liquid to such an extent that it becomes viscous or pasty. As the drums 5 and 6 rotate they pick up a heavy, thick 20 layer of the boiling liquid solution. All the material so adhering to the drum surfaces as they pass through the boiling liquid solution in reservoir I6 is retained undisturbed on the drum surfaces and is not partly removed and accumulated before leaving this reservoir as is the case when the drums revolve in the opposite direction. The material adhering to the drum surfaces is quickly reduced to any desired moisture content which is governed by the density of the solution fed, the steam pressure and the speed of the drums. This layer can be readily stripped from the upper drums by doctor blades 23 and dropped directly onto the lower pair of rolls 1 and 8 in a highly viscous or pasty form. Since the lower rolls 1 35 and 8 rotate toward each other at their point of closest approach they are able to handle this viscous liquid by forcing said viscous liquid between the drums and against the drum surfaces so that said viscous liquid is pressed into a thick m adhering to the under surfaces of the drums which emerge from their point of closest approach and can be quickly dried to any desired degree before being removed by doctor blades 24. A surplus of material may be allowed to accumulate in the receiving space I8 if desirable. The doctor blades 24 scrape the dry material into longitudinal screw conveyors 25 which in turn deliver the dry material to a cross conveyor 26. This cross conveyor 26 delivers the dry material 50 to an elevator 21 which discharges at 28 into a grinder 30 from which the material is deposited into suitable containers.

In using the double drum drier forming the subject of this invention the solution, if necessary,

is ilrst concentrated preferably in a multiple effect vacuum evaporator to a concentration which can be effected with a centinuous flow of material and without danger of discoloration. While a higher concentration frequently could be effected in an evaporator it is not desirable because often the liquid would not flow smoothly through the pipe 22 and upon being deposited in the reservoir i6 would quickly become viscous or pasty, would thereupon not boil freely, wonld then often have a tendency to discolor and would not be deposited on the drum surfaes in a uniform and suitable coating. y

This concentrated solution is deposited preferably without cooling to any great extent in the reservoir IB and is held in this reservoir for a short time. The steam pressure in the upper drums 5 and C is preferably mantained at a suitable pressure, so that the solution so held in the reservoir I6 boils freely and a considerable amount of water is evaporated. As the drums rotate upwardly at their point of closest approach each picks up a heavy layer of the boiling solution and quickly reduces it to any desired moisture content, which is controlled by the density of the liquor fed, by the level of said liquor in its reservoir I6, and by the steam pressure and speed of the drums. These layers are preferably reduced to a highly viscous condition, the drying period of the layers on the drum surfaces being such that the quantity of viscous material produce-d is not in excess of the amount which is dried on the lower drums and I in the same period of time, The heavy layers of viscous material are then scraped from the drums 5 and S by the doctor knives 2l and deposited directly on the lower pair of drums 1, l. These dnxms immediately carry the partly dried material into the reservoir il between the lower pair of drums. As the drums l and l rotate the material is gradually forced between these drums and against the drum surfaces so that a thick film of viscous material is deposited on the drinn surfaces as they leave their point of closest approach and can be dried to any desired degree by regulating the clearance between the drums, the

steam pressure and the drum speed.

It will be understood that the moisture content may be varied, if desired, by increasing or decreasing the clearance between the drums l and I by means of any usual and well known means, such as the movable bearings and screw adjust-ments indicated at 28, or by varying the steam pressure or drum speed. Actual steam pressure and time of contact allowed with both sets of drums is regulated to correspond to the nature of the soiution.

From the foregoing it is apparent that the drum drier forming the subject of this invention provides a low cost drier which will quickly reduce solutions to a dry stable form.

While the invention is particularly applicable to the drying of whey, it will be appreciated that the drier can also be used in drying other materals, particularly those having similar characteristics.

While I have shown specific apparatus and described a specific process capable of being perfumed therein, it will be understood that the invention is not to be limited to such specific apparatus or pre-cess but is to be accorded the full range of equivalents comprehended by the acoompanying claims. In particular by the term drier" as used herein is meant apparatus which eliminates moisture from a liquid being processed and converts this liquid to a solid state regardless of the nature or condition of the media supplied to the several drums thereof.

I claim as my invention:

1. A two stage drier, comprising upper and lower pairs of heated closely spaced drums each pair b-eing arranged parallel with one another and having end boards forming a reservoir between the drums of each pair, means for deposit= ing the material to be dried in liquid form in the upper reservoir, means for rotating the upper drums in the direction in which their surfaces travel upwardly at their point of closest approach whereby each upper drum picks up a heavy layer of liquid from the upper reservoir, means for removing said layers from the lower parts of said upper drums and permitting them to fall by gravity onto the lower drums, means for rotating said lower drums in the direction in which their surfaces travel downwardly at their point of closest approach to thereby force the material falling from said upper pair of drums between said lower drums to be depc-sited and dried thereon in layers and means for removing me dried material from the upper parts of said lower drums.

2. A two stage drier. comprising a pair of heated drums arranged parallel with one another and forming a valley therebetween, end boards at the ends of said drums and forming a reservoir in said valley, means for depositing the material to be dried in liquid form insaid reservoir, means for rotating said drums in the direction in which their surfaces travel upwardly at their point of closest approach whereby each drum picks up a heavy layer of liquid from said reservoir, means for removing said layers from the lower parts of said drums, a second pair of drums arranged parallel to one another and directly under said .rst pair of drums and receiving the material falling by gravity from said removing means, means for rotating said second pair of drums in the direction in which their surfaces travel downwardly at their point of closest approach whereby the material dropping from said upper pair of drums is forced between said second pair of drums and spread into layers thereon, means fer maintaining said second pair of drums at such temperature as to convert said layers to a sohd state and means for removing the solidified material from the upper parts of said second pair of drums.

3. A two stage atmospheric drier, comprising upper and lower pairs of closely spaced drums each pair being arranged parallel with one another and having end boards forming a reservoir between the drums of each pair, means for depositing the material to be dried in liquid form in the upper reservoir, means for rotating the upper drums in the direction in which their surfaces travel upwardly at their point of closest approach whereby each upper drum picks up a heavy layer of liquid from the upper reservoir, means for heating said upper pair of drums, means fcr removing said layers from the lower parts of said upper drums and permitting them to fall by gravity onto the lower drums, means for rotating said lower drums in the direction in which their surfaces travel downwardly at their point of closest approach to force the material falling from said removing means between said lower drums and spread the material into layers therm. means for maintaining said lower pair of drums at such temperature as to convert said layers to a solid state and means for removing solidied material from the upper parts of said lower pair of drums.

4. A two stage drier, comprising a pair of heated drums arranged parallel with one another and forming a valley therebetween, end boards at the ends of said drums and forming a reservoir in said valley, means for depositing the material to be dried in liquid form in said reservoir, means for rotating said drums in the direction 1o in which their surfaces travel upwardly at their point of closest approach whereby each drum picks up a heavy layer of liquid from said reservoir, means for removing said layers from the lower parts of said drums, a heating surface arranged under said last means and onto which said removed layers fall by gravity, means for heating said last heating surface and means for removing the dried material from said heating surface.

CHARLES O. LAVE'I'I.

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