US3438520A

US3438520A - Slug filling of bins

Info

Publication number: US3438520A
Application number: US565263A
Authority: US
Inventors: Merl A Williams
Original assignee: Central Soya Co Inc
Current assignee: Central Soya Co Inc
Priority date: 1966-07-14
Filing date: 1966-07-14
Publication date: 1969-04-15
Anticipated expiration: 1986-04-15

Description

M. A. WILLIAMS SLUG FILLING OF BINS April 15, 1969 ile@ July 14. 196e INVENTOR. Merl A. Williams @awwnlmzalmz l; Armen/Fys United States Patent O U.S. Cl. 214-152 4 Claims ABSTRACT F THE DISCLOSURE Material of varying particle size and density is filled lnto bins in a manner which avoids the segregation of the particles. rIhe material is formed successively in slugs over the bin and then allowed to drop one by one into the hin, and under the impact of the fall the particles are uniformly distributed, producing a flat top of material in the bin.

This invention relates to the slug filling of bins, and more particularly to the filling of bins with material of varying particle size in a manner which avoids the segregation of particles.

The problem of segregation in the filling of bins has long been recognized. In discharging a continuous stream of material of varying particle size, density, etc., the material falls continuously upon the apex of the cone of the material already present in the bin, The cone normally has two cone angles, the angle of repose being steeper toward the center of the cone than it is toward the outside. The steeper cone angle at the center is caused by the higher angle of repose of the fine materials which congregate there and by the compaction of these fine materials from the impact of the material falling on the apex. The larger particles move toward the outside of the bin and form a lesser angle of repose due to their particle size and the fact that they arrive at this location in a free-flowing, rolling fashion.

During continuous filling, the larger particles in the stream arrive at the apex of the cone free of any attractive or cohesive forces toward the mass of the material and immediately roll freely down the steep center cone toward the outside of the pile. At the same time, the finer particles are building up in the center, and eventually enough pressure height is obtained at the center to develop a shearing force in the body of the fine material to cause a slab of this material to move downward. This phenomenon occurs at more or less regular intervals during the lling of the bin. The movement of the fines, due to the shear plane effect, is a mass movement, the entire body of material moving as a unit without any unmixing effect. In contrast, the rolling of the large particles down the cone is completely different in that each particle behaves as a separate entity and rolls as far as its inertia and the presence or absence of obstruction to rolling will permit. In any event, all of the foregoing phenomena result in a segregation of the material particles, with the result that even though the material filled into the bin may represent a carefully and uniformly mixed body of material suitable for a feed composition or other use, the filling process as above described destroys the uniformity of the mixture so that the material drawn from the bottom of the bin no longer represents the desired feed mixture, etc.

While the segregated materials in the bin can be remixed at the discharge for certain portions of the discharge cycle if the bin hopper is specially designed, for many materials such design results in excessive hopper heights, and this approach may not be practical. Further, even with such a properly designed hopper, the final ICC quantities of discharge from a segregated bin will still show very pronounced variations in properties.

I have discovered that by collecting the stream of material into slugs and then discharging the slugs intermittently onto the body of material in the bin, segregation can be eliminated, and a product may be drawn from the bin which is substantially the same in character and composition as that filled into the bin. Such slug filling results in the contents of the bin being completely and uniformly mixed, duplicating throughout the bin the mixture of material which is put into the bin. Thus one can discharge a uniform mix from the bin since whatever portion of the contents should happen to come from the bottom of the discharge opening will be of the same composition as any other portion in the bin.

A primary object, therefore, of the invention is to provide a method and means for filling a bin with a material varying in particle size or composition without segregation of the particles. A further object is to provide a method for eliminating segregation of particles in a mixture containing fines and larger particles as the material is filled into a bin. A still further object is to provide a process for slug filling a bin to maintain the material uniformly mixed so as to duplicate the mixture of material put into the bin. Other specific objects and advantages will appear as the specification proceeds.

The invention is shown in an illustrative embodiment by the accompanying drawing, in which:

FIGURE 1 is a diagrammatic View in section of a bin as it is filled by a continuous stream of material; FIG. 2, a view similar to FIG. l but showing means for collecting the stream of material in a slug and for intermittently dropping the slug onto the material within the bin; and FIG. 3, a View similar to FIG. 2 but showing a smaller container and the dropping of a relatively small slug of material onto the flat top of the cone within the bin.

In the illustration given in FIG. l, 10 designates a bin and the material of varying particle size is delivered through a spout or other means as indicated by the arrow 11 onto the apex 12 of a cone of material within the bin. The bin is provided with valve or other means for controlling the fiow of the material from the discharge end 13 of the bin 10.

In the illustration given in FIG. 2, the stream of material through line 14 enters a receptacle 15 which is closed at its lower end by a draw slide 16. After the receptacle 15 is filled, the draw slide 16 may be moved laterally by the handle 17 to permit the slug 18 within the receptacle 15 to fall onto the flat surface 19 of the body of material 26 within the bin 10a. In this operation, where the slug may, for example, be about 300# and may fall about 20', the top surface 19 of the material within the bin is fiat practically all the way across, thus forming what may be called a water level.

In the modification shown in FIG. 3, the bin 10b is provided with a proportionately smaller receptacle 15a and a slide 16a operated manually by a handle 17a. The size of the slug 18a discharge may, for example, be about 1l# and the flat top 19a may be only about 24". In either the structure shown in FIG. 2 or the structure shown in FIG. 3, a uniform mixture may be withdrawn from the

outlet

13a or 13b which substantially duplicates the mixture of material introduced into the bin.

In the operation of the illustrative apparatus shown in FIGS. 2 and 3, the continuous stream of material is allowed to fill the receptacles 15 and 15a, and then the slide 17 or 17a is rapidly pulled to open the receptacle to permit the slug to fall into the bin. The

slug

18 or 18a arrives at the level of the material in the bin with a considerable amount of kinetic energy. This kinetic energy 3 results in a shock to the pile of material causing it to move en masse toward the outside. The material has a flat top and a lesser angle of repose leading from the edge of the flat top to the edge of the bin wall. The flat top causes the kinetic energy transmitted to the material to activate a shear plane within the mass of the material to cause the material to move en masse toward the outside. The contents of the bin thus move uniformly to the outside of the bin without unmixing and are thus completely and uniformly mixed to duplicate the mixture of the material put into the bin.

The size of the slug and the length of the drop are not critical. A very large slug, such as, for example, 300#, and a drop of or more into a bin having a lateral width of about 8 produces a fiat top surface of the material in the bin so that such surface may be said to have a water level. However, smaller slugs and a shorter distance of drop while failing to give a water level, nevertheless maintain the desired uniform mix of ingredients in the bin. Tests in a small 6 bin with a drop of about 4' or so using a slug of about 7 gave a good uniform mix. As long as the continuous stream to the bin is stopped and slugs of the mixed material are intermittently dropped into the bin to form a cone having a flat top, the desired uniform mix is obtained. Intermittent slug filling of the bin produces a fiat top at the apex of the cone, and the fiat top is effective in producing the uniform mix as above described. By flat top, I mean the portion at the top of the cone which is fiat and where the slug hits the material level. The fiat top will become wider as the slug size and length of drop are increased, but where the slug size and length of drop are substantially decreased, there is still a fiat top at the apex of the cone for producing the en masse movement of the material outwardly to provide the uniform mix duplicating the mixture of material filled into the bin.

Specific examples illustrative of the invention may be set out as follows:

EXAMPLE I A composition of feed ingredients, known as Steer Mixer, was fed in slugs to a feed mill bin, the feed stream being directed into a 13" round pipe made of 14 gauge metal high. At the bottom of the pipe was a manually-operated slide that opens the full width of the pipe for discharging the mixed mash as a slug into the bin. Each slug weighed between 116 and 120 pounds. The slug of the mix was dropped to the material level in the bin, which was about 70' below the receptacle. There was a fiat top of about 4 on the top level of the material during the run. The process resulted in the contents of the bin being completely and uniformly mixed and duplicating the mixture of material which was fed through the slug-forming apparatus. The material drawn from the bottom of the bin or discharge opening was of the same composition as the material fed to the bin.

EXAMPLE II Tests were carried out on two different types of bins. One bin was 2 x 2 x 4', with a side discharge. The other bin was the same except that it had a center discharge, each bin being square in cross section. A cattle feed, known as 65% Cattle Formula, was used in the tests and included in its composition urea, soybean mill feed, gluten feed, limestone, phosphate, soybean meal, cottonseed meal, molasses and vitamins.

Tests were made with each of the bins using a continuous .stream feed to the bins. Afterwards the bins were drained and each was slug-filled as follows: The continuous stream was accumulated in about 7# batches and the batches dropped into the center of the bin. By dropping the batches, the cone in the center of the bin was eliminated and a fiat top of `feed material was maintained.

No substantial difference was found in the operation of the slug filling, Whether using the side discharge bin or the center discharge bin. In the slug filling of the two bins, it was found that there was very little segregation, and the product later drawn from each bin substantially duplicated the mix fed to the bin. In contrast, the filling of the two bins by a continuous stream brought about a very substantial segregation of the large particles from the small particles, and the material withdrawn from the bin was unlike the composition lfed to the bin by the continuous stream method.

EXAMPLE III The process was carried out as described in Example II except that instead of a feed composition, 50% soybean meal was fed to the bins. By 50% soybean meal is meant a finished particulate meal containing about 50% protein. The process was carried out in a 2 x 2 x 4 bin with a center discharge holding about 450# of meal. The bin was filled with a continuous stream and the contents examined, and later the bins were filled again using intermittent `slug filling. It was found that the slug feeding of the mill bin improved the uniformity of particle size of the soybean meal throughout the bin substantially above that obtained when the bin was filled continuously. There was too much particle size segregation when the bin was filled with a continuous stream through a straight spout.

EXAMPLE IV Tests were carried out in the manner described in Example I except that the tests were conducted with different sizes of slugs and with varying heights of fall. It was found that the flat top became wider as the slug size and length of drop were increased. The results are set out in the following table:

Height of Size of Size bin Measurements Height of fall slug (lb.) (it.) across the flat cone (in.)

top (in.)

6 54 5. 5 44 6 43 10. 0 11 24 19. 0 11 G 12 or so 26.0

In contrast with the above results, when the same bin was lled by a continuous How of the material, a uniform mix of the bin was not obtained. In the latter test, the height of fall was 14 9, the size of the -bin was 6', the height of the `cone was 31, and the top of the cone had a very minor expanse and would not -be described as a flat top.

While in the foregoing description, the apparatus for forming the slugs is a manually-operated device consisting of a slide and `a draw bar, it will be understood that the feeding of the slugs can, if desired, be accomplished `by automatic mechanical devices such as, for example, receptacles which dip to discharge their contents after being filled while bringing a `successive container into position for receiving the fiowing stream. Further, it will be understood that the bins may be of various types and design and equipped with discharge mechanism for directing the mixture to pellet machines and other devices.

While in the foregoing specification I have set forth procedure and apparatus in considerable detail for the purpose of illustrating embodiments of the invention, it will be understood that such details may be varied widely -by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In a process for filling material varying in particle size into a bin without substantial segregation of the particles, the steps of forming all of the material successively into slugs over the bin, and dropping each slug as it is Y 5 formed into the bin to build up a body therein having a at top.

2. The process of claim 1 in which the slugs are formed by collecting the material from a continuous stream into a container and then quickly opening the container.

3. The process of claim 1 in which the material lled into the bin consists of a composition of different materials varying in particle size and density.

4. In a process for lling a stream of material varying in particle size into a bin Without substantial segregation of the particles, the steps of collecting a stream of said material in successive slugs, and dropping each slug as it is formed into the bin to build a body therein having a flat top.

References Cited ROBERT B. REEVES, Primary Examiner.

10 H. S. LANE, Assistant Examiner.

U.S. Cl. X.R.