US2903054A - Drum dryer feed distribution apparatus - Google Patents

Description

p 8, 1959 A. M. FISCHER 2,903,054

DRUM DRYER FEED DISTRIBUTION APPARATUS Fild March 10, 1955 2 Sheets-Sheet 1 FEED . ATTORNEY p 8, 1959 A. M. FISCHER 2,903,054

DRUM DRYER FEED DISTRIBUTION APPARATUS Filed March 10, 1955 2 Sheets-Sheet 2 INVENTOR 1445567/7/7506466 BY m fwu ATTORNEY ilnited States Patent DRUM DRYER FEED DISTRIBUTION APPARATUS Albert M. Fischer, Dowa'giac, Mi'ch., assignor to Davenport Machine and Foundry Company, Davenport, Iowa, a corporation of Iowa Application March 10, 1955, Serial No. 493,439

'3 Claims. (Cl. 159-43) The present invention relates to a dryer feed distribution apparatus and more particularly to an apparatus whereby the flow of feed material to drying surfaces is evenly distributed over the length of the dryer drums and where the flow from such distribution apparatus is quickly and positively controlled so that no substantial residual dripping can occur which would result in damage to the dryer surfaces or associated apparatus.

It is customary practice in the art of yeast drying, for example, to provide perforated pipes through which a yeast slurry is directly distributed between the surfaces of rotating drum dryers of the double drum type or some types of single drum dryers. The perforated pipe is suspended over the dryer. In the case of double drum dryers the yeast material is puddled between the drums and thus spread onto the drum dryer surfaces. Pendulum type feeders are also well known which oscillate while making distribution of the feed. Such feed apparatus have a common disadvantage inv that when the dryers are shut down the feed material continues to drip and dry on the hot drums, and the caked material then forces fracture of the shear pins or may even damage the dryer or associated apparatus when the dryer is started again. This difficulty is most serious where double drum dryers are used and misalignment frequently occurs where the cake forces the separation of the dryer drums. This is true in even brief shutdowns since the heat in the drums quickly solidifies the dripping yeast. Service to prepare such caked drums for return to operation is costly and time consuming. Frequently misalignment caused by the drip formed cake requires the skilled services of mill Wrights to restore the machinery to operation. Finally, there is little or no preheat of the fed yeast slurry in the presently known apparatus.

It is therefore an object of the present invention to provide a substantially dripless feed distributor.

It is another object to provide a feed distributor having positive shut-off so that when a drying machine is shut down no dripping of the feed material occurs.

It is another object to provide an apparatus for evenly distributing a flow of feed to the drum faces of dryers.

Another object of the invention is to obtain'better coating of the drums with the feed material to be dried. This is accomplished by extending the bafiles of the feed distributor far enough to the sides so as to assure that the descending films of the feed material contact the drums at points located approximately 45 degrees or less oif drum center.

Still another object of the present invention is to provide a feed slurry distribution apparatus wherein the apparatus serves as an efficient heat exchange surface and wherein the flow of slurry covers a broad surface thus preheating the feed and achieving substantial preevaporation in the feed system.

Other objects including simplicity of structure, adaptability to a wide range of feed distributor installations,

relatively service-free performance, and other objects will 2,903,054 I Patented Sept. 8, 1959 2 become increasingly obvious to those as the description proceeds.

Inthe drawing: Figure 1 is a plan view showing the positioning of the feed distributor apparatus over a double drum dryer. Figure 2 is an end elevation of the feed distribution apparatus positioned above and between the drums of a double drum dryer and-indicates, the manner of its suspension from the hood or dryer frame members.

Figure 3 is a side elevation view of a simple form of feed distributing apparatus in accord with the present invention.

Figure 4 is an end elevation of. the structure shown in Figure 3.

Figure 5 is a side elevation view of a modified feed distributing apparatus in accord with the present invention and illustrating the use of a perforated feed tube suspended over the trough.

Figure 6' is an end elevation of the structure'shown in Figure 5.

Figure 7 is an end view of a modified form of the inventive structure showing. a single inclined planar baifie. Figure 8 is a schematic flow diagram showing the simplest solenoid form of valve coordinating means as between supply line and dumping to reservoir from the drainline.

skilledintheart General description In general, a lippedlevel trough is provided. A feed inlet tube permits the feed material in slurry form to How into the trough portion with relatively even distribution. As the level of feed rises in the trough, the feed material flows uniformly over a lip and over an inclined bafile forming a spillway to flow the feed uniformly thereover in a thin film of substantially equal depth. The feed material flows oif the bafile and onto the dryer surface 'in'a uniform stream. In double drum dryer installations a double lip, one on each side of the trough, distributes materials to both dryer drums simultaneously. The surface area provided by the baflle and the film-like flow over the baffle assists in pre-heating the feed material prior to its contact with the dryer drum surfaces and thus makes use of the rising steam and radiating heat from the dryers. The apparatus flows feed onto the dryer drums only inresponse to arising level of feed material in the trough. Valving is provided in the feed line to the distribution apparatus and in the drain line therefrom. If a dryer shut down is necessary and the valve to the distribution apparatus is closed no dripping can occur and the flow to the drum surfaces stops substantially with the closing of the valve. The simultaneous opening of a drain valve provided below the level of full trough prevents a possibility of drip by exhausting the feed slurry from the'trough. As will be seen, automatic linkage can be applied to render the valve shut off automatic in coordination with any interruption of the dryer movement. Simultaneously, the opening of the drain line avoids any possibility of-overflow. The baffles extend inclinedly toward the drum surfaces and terminate a short measured distance therefrom.

It will be seen that the thermal eificiency o'f dryers has been substantially enhanced by the distributing apparatus described and prolonged trouble-free operation characterizes the structure. Damage to dryers employing the drip-free feed distributing system has thus been reduced to new minimums. The feed trough assures better coating of the dryer drum with the feed material. This is due to the fact that the descending feed film contacts the drums at a position about 45 degrees or less oif drum center making possible more efiicient use of the dryer drum surface.

Specific description Referring more particularly to the drawings, at Figure 1 is the installation of a feed distributing apparatus 11 over a' double drum dryer 12. The double drum dryer 12 is shown in light lines and is illustrative of one installation. In Figures 1 and 2 the feed distributing appara tus 11 is presented in plan and end elevation respectively to illustrate the position of the tube 13, elongate trough 14, lips 15 and 15a and drain connection 16. The pipe connection inlet 17 is shown to indicate the connection to a feed supply line 18 as shown schematically in Figure 1. Likewise the drain 16 is shown schematically with valves 19 and 19a, where valve 19 is the feed inlet valve.

The trough 14 longitudinally cradles the tube 13. The tube 13 delivers feed material to the trough 14 at one end. The other end of the trough 14 is substantially closed except for a drain pipe 20 having a drain opening connecting with a valved drain line 16 (Figure 1). The trough 14 is substantially U-shaped and is provided with inclined planar side baffles 22 and 22a. The baffles 22 and 22a are integrally connected to the trough 14 and form at the lips 15 and 15a the full level line of the trough 14. End barriers 23 and 24 close the trough 14 against the periph ery of the tube 13 at one end and the drain pipe 20 at the other end.

In Figure 5 a modified version of the dripless distribution system is illustrated where a delivery tube 25 supports suitable brackets 26 extending downward to support the trough 14. Where a vapor hood 27 is employed, as in Figure 2, attachment of the delivery apparatus 11 is simply made by the attachment of adjustable screw bolts 28 .to the hood 27. The adjustable screw bolts 28 provide simple leveling means for the apparatus 11. The feed tube is perforated uniformly as indicated at 29 to deliver feed material in streams to the trough 14. Where yeast slurries constitute the feed, orifices 29 of approximately 4 inch diameter have proved most satisfactory. As previously described, the lips 15 and 15a of the trough 14 determine the liquid level of the trough 14 and the feed material spills uniformly over the baffies 22 and 22a and onto the drum surfaces 30 and 30a. In this modification the trough 14 is provided with a drain nipple '31 connected to a suitable drain line 16 (Figures 1 and 5). The advantage of this modification is to evenly distribute the feed material over the entire length of the trough 14 and thus assure uniform overflow over the lips 15 and 15a. It can be seen that the feed material will be preheated while in the trough 14 and while flowing over baffles 22 and 2211 due to the large amounts of steam emanating from the boiling feed material between the 'drums 30 and 3001, as well as the heat radiation from the drums 30 and 30a. Further preheating takes place as the film of material flows from the baffles 22 and 22a onto the drums 30 and 30a as illustrated in Fig. 2. Such diffusing has been found to contribute to a desirable pre-evaporation or pre-drying of the feed slurry. It will be observed that the trough 14 and the downwardly inclined planar baflles 22 and 22a are similar in both modifications. I

In Figure 7 it will be seen that a trough 14 embodying the principles demonstrated in the previously described structure is provided but that only one baffie 22 and one lip- 15 is provided. This modification is obviously for use where only a single surface is served by the distributing apparatus 11a.

In all forms of the distribution apparatus the baffles 22 and/ or 22a extend outwardly and downwardly from above the dryers 12 so as to distribute material to the drums 30 and 30a within a quadrant about 45 degrees or less off drum center, as shown in Figure 2.

The material comprising the troughs 14 and batfies 22 and 22a is preferably non-corrosive sheet metal of sulficient gauge to provide support strength while providing a maximum thermal exchange function as a thermal 4 exchange barrier interposed between the rising heat source from the dryer drums 30 and 30a and the boiling feed material.

The feed line 32 is valved as at 19 and the drain line 16 is provided with a drain valve 19a. While these valves 19 and 19a are manual in smaller installations it will be understood that coordinated automatic controls are available such as solenoids, hydraulic or pneumatic actuation so that when the feed valve 19 is open the drain valve 19a is closed and when the feed valve 19 is closed the drain valve 19a is open. Similarly the actuation of these valves 19 and 19a can be coordinated with the actuating means for the dryers 12 for example, so as to cause desired operation depending upon whether or not the dryer machinery is functioning. In Figure 8 there is illustrated a simple form of coordinating means wherein the valves 19 and 19a are actuated by solenoid means. The combination valves and coordinating means C is available commercially from the Hannafin Corporation of Des Plaines, Illinois, and other valve manufacturers. While solenoid coordinating means are convenient, it will be appreciated that other manual, hydraulic, and pneumatic controls well known in the art are also useable. In such a manner stoppages are instantaneously sensed by the distribution apparatus 11 and no damage from dripping feed to hot drum surfaces can occur. Since such automatic actuation is non-inventive per se and well known in electrical, hydraulic, and pneumatic control art no specific description is believed necessary of equivalent control means for coordinating the valve actuation.

Operation In operation, for example, with double drum. dryers 12 the distribution device 11 is suspended absolutely level above the rotating drum surfaces 30 and 30a and the longitudinal axis of the trough 14 is located directly above the line of approximate contact between the drums 30 and 30a. The planar downwardly inclined baffles 22 and 22a extend above the drums 30 and 36a as best illustrated in Figure 2. The trough 14 is filled by opening the valve 19 and closing the drain valve 19a. As the trough 14 fills beyond the level of the lips 15 and 15a the feed material spills uniformly down the baflles 22 and 22a and drops onto the drum surfaces 30 and 30a. The baffles 22 and 22a thus form a film flow spillway uniformly distributing the feed material slurry to the dryer surfaces. The location of the distribution apparatus 11 and its construction permits the feed material to be preheated by the otherwise lost rising steam and radiated heat from the heated dryers. The surface exchange area represented by the trough 14 and baffles 22 and 22a and even the free drop of film flow from the baffies 22 and 22a contributes to the overall thermal efiiciency of any dryer unit.

In the instance of the modification shown in Figure 5, the free drop from the suspended feed tube 13 is an added element contributing to preheat and consequent drying 'or evaporation.

The use of the instant apparatus with single drum dryers follows the operational description above except that flow of feed is over one baffle 22 as illustrated in Figure 7.

In operation higher dryer production has resulted from installations utilizing the apparatus described and machinery damaging drip has been substantially eliminated. In use with either manual or automatic inlet and drain valves the structure has obtained an excellent reception in the drying art and in particular the yeast drying field.

While the description has related the apparatus to the yeast drying field it will be understood that the feed distributing apparatus is of broader scope wherever the uniform feeding of a material slurry is desired to evaporator or dryer surfaces, and whether those surfaces be planar or cylindrical, as in the instance of drum dryers.

Having thus described my invention it will be understood that certain modifications within the skill of the art are intended to be included as limited only by the scope of the hereinafter appended claims.

I claim:

1. In a feed distributing apparatus for supplying drum dryers with a continuous slurry of preheated material, the combination including: a leveled trough having side walls and positioned over a rotary drum dryer to receive radiant heat therefrom; planar bafiies extending downwardly and outwardly from said side walls and forming a spillway for slurry material; lips at the juncture of said balfies and said side walls defining a liquid level over which slurry material flows film-wise across said baffles; a feed inlet delivering said material to said trough; a drain line for emptying said trough; a valve in said inlet and a valve in said drainline; and valve coordinating means for opening one of said valves and simultaneously closing the other of said valves.

2. In a feed distributing apparatus for supplying drum dryers with a continuous slurry of preheated material, the combination including: a leveled thin-walled trough having side walls and positionable over a rotary drum dryer to receive radiant heat therefrom; planar bafiles extending downwardly and outwardly from said side walls and forming a spillway for slurry material; lips at the juncture of said baffles and said side walls defining a liquid level over which slurry material flows film-wise across said baflies; a feed inlet delivering said material to said trough; a drain line for emptying said trough; a valve in said inlet and a valve in said drainline; and valve 6 coordinating means for opening one of said valves and simultaneously closing the other of said valves.

3. In a feed distributing apparatus for supplying drum dryers with a continuous slurry of preheated material, the combination including: a leveled thin walled trough having side walls and positionable over and between a pair of parallel axised rotary drum dryers to receive radiant heat therefrom; planar bafiles extending downwardly and outwardly from said side walls and forming a spillway for slurry material; lips at the juncture of said baflies and said side walls defining a liquid level over which slurry material fiows film-wise for delivery to each of said rotary drum dryers; a feed inlet delivering said material to said trough; a drain line for emptying said trough; a valve in said inlet and a valve in said drainline; and valve coordinating means for opening one of said valves and simultaneously closing the other of said valves.

References Cited in the file of this patent UNITED STATES PATENTS 849,003 Macklind Apr. 2, 1907 1,604,036 Golding et a1. Oct. 19, 1926 2,330,922 Riegler Oct. 5, 1943 2,357,868 Beardslee Sept. 12, 1944 2,392,382 Harcourt Ian. 8, 1946 FOREIGN PATENTS 330,129 Germany Dec. 8, 1920 123,534 Sweden Dec. 7, 1948

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