US3029723A - Compacting device - Google Patents

Description

April 17, 1962 H. SCHWEER COMPACTING DEVICE Filed July 26, 1960 3,029,723 COMPACTING DEVICE Herman Schweer, Greendale, Wis., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed July 26, 1960, Ser. N0. 45,431 4 Claims. (Cl. 99237) This invention relates in general to roller mills and in particular to roller mills of the type used to produce sheet and flake products. I

' When compacting material in a roller mill, it sometimes becomes necessary to force feed the material to the rolls. This is especially true when compacting low density materials, for example cornstarch, because flufiiness of the material enables the material to remain suspended above the rolls. Only by creating a pressure such as by means of a force feeder, to force such material through the rolls, is it possible to compact these materials. In a like manner force feeding may be used for compacting high density material that resists flow through the rolls.

It is desirable that the sheets and flakes produced be uniform. For instance, in the manufacture of breakfast foods, if the flakes of cereal were not of uniform thickness, it would not be possible to evenly toast the flakes, resulting in a breakfast food having flakes that are both raw and burnt.

Force feeding the material to the rolls does not always yield a uniform product. A problem arises in that the air and moisture entrained in the material becomes entrapped at the nip of the rolls. The entrapped air or moisture will build up at the nip preventing portions of material from passing through the rolls and when the entrapped fluids build up enough to be forced through the rolls, a blow hole or void will be formed in the compacted product.

In my copending US. application Serial No. 26,825, filed May 4, 1960,. I disclose a machine of the type referred to, in which a hollow vane is placed within a feed bin. The feed bin is placed to deliver feed to a pair of rolls. The vane is suspended within the bin to extend into the roll valley just above the nip of the rolls. The vane extends longitudinally parallel to the axis of the rolls, a distance substantially equal to the length of the rolls that receives material from the feed bin. The sides of the vane that are thus substantially parallel to the roll axis are smooth and taper inwardly toward the nip to thereby present a streamlined surface for guiding flow of material to the nip and yet enabling the vane to be positioned in the valley close to the nip. The vane provides an entranceway for fluids, such as air and water, entrapped above the nip. The inner side surfaces of the vane taper outward in the direction away from the nip to thereby define a uniformly expanding escape passageway. Since the rolls squeeze entrained fluid out of the material passing therebetween, the fluid is entrapped between the nip and the pressures of the force feedertoward the nip. Therefore the fluid is under pressure as it enters the vane, and since the escape passageway affords a uniformly increasing volume of space in a direction away from the nip, the fluid will expand into the passageway and be induced to flow outward from the nip. V

The present invention provides a further improvement over the teachings and practices of the prior art. According to the present invention, a mill is provided with a vane such as is disclosed in my copending application, and the vane is provided with a tip portion that conforms to the taper of the vane but completely encloses the entranceway to the escape passageway. However, the tip portion is made of an air and water vapor permeable porous material, such as a metal screen having openings,

3,629,723 Patented Apr. 17, 1362 in a preferred embodiment, of approximately five micron size. Thus, air and water vapor entrapped above the nip of the rolls is permitted to enter the escape passageway but fine particles of material being compacted will not be drawn into the escape passageway. Since the tip portion is within the feed bin and in close proximity to the nip of the rolls, material flowing through the feed bin will flow down the tapered surfaces of the vane and its tip portion, thereby brushing the porous surfaces clean of material that otherwise would tend to plug up or block the openings because of being drawn against the tip portion by the egress of air. The material so brushed from the tip portion will be carried by the stream of material flowing to the nip of the rolls and through the mill thus eliminating waste that would occur by such fine material escaping with air and water vapor. In addition to thus increasing the efficiency of operation, safety 7 is promoted by eliminating dust from escaping air that could be an explosive mixture.

Accordingly, it is a primary object of the present in-' vention to promote efficient and safe operation of compacting devices and the like.

A further object of the present invention is to provide a new and improved escape means in compacting machines and the like for enabling entrapped gas and liquid to escape.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawlllgS.

FIG. 1 is a sectional side view of a compacting machine having a bleeder vane;

FIG. 2 is a view taken in the direction of line II--H of FIG. 1 showing a single roll of a pair journaled in schematic bearings together with sectional portions of a bleeder vane, and a feed bin; and

FIG. 3 is an enlarged sectional view of the vane shown in FIG. 1 taken in the direction of line IIIIII of FIG. 2.

With reference to the drawings and FIG. 1 in particular, a pair of parallel compacting rolls 1t), 11 is shown operative for use in a compacting machine of the type used to produce flaked and sheet products. A roll valley indicated at 14 and a nip indicated at 15 are formed between the surfaces of the roll as illustrated. The rolls 10, 1 1 rotate in the direction indicated by the arrows of FIG. 1 so that material fed therebetween may be compacted into sheets and flakes.

A feed means such as a feed bin 18 structurally shown in FIGS. 1 and 2 is positioned above the rolls 10, 1 1 to direct material into the rolls for compaction. As illustrated, the bin 18 may be flange connected to a supply conduit 19 supplying material under pressure from a force feeder (not shown).

Since a force feeder rather than gravity may be relied upon to feed material to the rolls 1t), 11, application of this invention is not limited only to compacting machines having a pair of horizontally displaced rolls. In fact, the rolls 1t), 11 shown in a preferred embodiment in the drawings may be taken to be disposed along any plane including a vertical plane. Therefore, it is not meant to limit this invention to a roller mill having horizontal rolls.

A tapered hollow bleeder vane 20 is positioned in the valley 14 between the rolls 10, 11 to afford an escape passageway 21 for fluids entrapped at the nip 15. The vane 20 may be fashioned out of two sheet metal pieces numbered 23 and two pieces numbered 24 shaped and bent to the cross sectional configuration shown in FIGS. 2 and 3. The opposed open ends of the sheets 23 are enclosed by end pieces 25. The outboard end pieces 25 may include a circular flange portion 26. Pieces 23, 24

escape passageway 21 within the vane 24 An exit opening 27 may be provided in each-flanged portion 26. This preferred embodiment of the vane is then supported by the flange portions 26 and suspended from the feed bin 18 as shown in FIGS. 1 and 2. As illustrated, a pair of exit ducts 28 may be connected to the flange portions 26 at exit openings 27 to provide an outlet for entrapped fluids. In some cases it may be desirable to attach some means as a suction pump (not shown) to create a negative pressure, and thereby facilitate exit of the fluid.

The vane 20 is provided with a tip portion 39 that conforms to the taper of the vane and a completely enclosed passageway 21. The tip portion 30 is made of an air and water vapor permeable porous material, such as a metal screen having openings of micron size. For compacting a material such as cornstarch, a suitable size opening will be approximately five micron. Other materials may require openings of larger size. The range of size of the openings for handling most materials that are handled by compacting devices and the like will be within a range of from five to 1000 micron size. The tip portion 30 may be formed by bending a single sheet of metal screen to the configuration in FIG. 3. The sheet 31 may be attached to the vane 2t} in any suitable manner such as welding the edges of sheet 31 to the pieces 24 as shown in FIG. 3. The opposite end openings of the sheet 31 may be enclosed by end pieces 3-2 which may be of the same porous material as the sheet 31. Since most porous materials willbe somewhat flexible, it will be desirable to provide rigidity for the tip portion 30 by means of stiffening webs 33. To promote an evenly distributed flow of air and water'vapor through the tip portion 30 the stiffening webs may also be made of the same porous material as the sheet 31 and end pieces 32. Even though the stiffening webs may be made of a porous and therefore relatively flexible material, the fact that a plurality of such webs are spaced along the lateral length of the tip portion will result in the tip portion being sufficiently stiflened and made rigid for the purposes herein disclosed. The stiffening webs 33- like sheet 31 and end pieces 32, may be secured to the assembly by any suitable means such as welding. I

The tip portion 30 projects to within close proximity ofthe nip 15 of rolls 10, 11. More specifically, the tip portion 30 projects through a plane A-A in FIG. 1 into the valley 14 enclosed by plane A-A. Plane A-A is a plane bordering the valley 14 and tangent with the outer surfaces of rolls 10, 1.1. In a machine such as is shown in FIG. 1 wherein compacting rolls are horizontally disposed, plane A--A is then, of course, also a horizontal plane.

In the operation of the machine described, the material to be compacted is fed under pressure from a force feeder (not shown) through the conduit 19 to the feed bin 18. The material will flow over and past the surfaces of the tapered bleeder vane 20 and its tip portion 36 and be guided toward the rolls it), 11. The material will feed into the nip 15 and through the rolls 10, 11 emerging as a uniform compacted product. Any air, vapor or other fluidlike material or gas that is squeezed out of the material and entrapped at the nip 15 will pass through the porous tip portion 30 of vane 20, through the escape passageway 21 and out exit openings 27 to exit ducts 28. As such gases, vapor or other fluidlike substances are under a pressure from the force feeder greater than atmospheric pressure, the gases and vapors will be urged through the escape route to be vented to the atmosphere. However, in some cases it may be desirable to provide a suction pump to improve the flow of en trapped fluid out through the vane.

Although air and gases such as water vapor will pass through the tip portion 30 to the escape passageway 21 fine particles of the material being compacted will-be blocked from entering the escape passageway. Since the tip portion 30 is within the feed bin 18 and is in close proximity to the nip 15 of rolls 10 11, material flowing through the feed bin will flow over the tapered surfaces of the vane and its tip portion, thereby brushing the porous surfaces clean of material that otherwise would tend to plug up or block the openings because of being drawn against the tip portion by the egress of air. The material so brushed from the tip portion 30' will be carried by the stream of material flowing to the nip 15 of the rolls 10, 1.1 and through the mill. Thus it can be seen that the present invention provides for preventing the waste of fine material escaping through the vent along with air and water vapor. In addition to thus increasing the etliciency of operation by eliminating material waste, safety of operation is also promoted by eliminating dust from escaping air that could be an explosive mixture. Accordingly, it can be seen that the described machine accomplishes the objects of the" present invention. 1

Although but a single embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. It is therefore intended that the present invention be limited only by the scope of the appended claims.

Having now particularly described and ascertained the nature of my said invention and the manner in which it is to be performed, I declare that what I claim is:

1. A roller mill for making sheet and fiakeproducts from pressurized material having air entrained therewith comprising: a pair of juxtapositioned rolls cooperable to compact material fed therebetween, said rolls forming a feed valley and nip therebetween, feed means including wall structure enclosing a space leading to said rolls for delivering said material under pressure to said valley; and a tapered hollow vane positioned within said feed means, a wedge shape screen having openings of approximately five micron size enclosing said vane, said screen being arranged with said wedge shape pointed toward said nip between said rolls to define with said vane a substantially continuous taper toward said nip for guiding said material to brush over the outer surfaces of said vane and said screen while being directed to said nip, said vane and said screen defining an air escape passageway having a pair of opposed side walls parallel to said valley and tapering away from each other in the direction away from said nip to define a substantially continuously expanding vent promoting outward flow of entrained air in said material. v 2. A roller mill for making sheet and flake products from pressurized material having air entrained therewith comprising a pair of juxtapositioned rolls cooper-able to compact material fed therebetween, said rolls forming a feed valley and nip therebetween, and said rolls defining a plane bordering said valley and tangent each of said rolls; feed means including wall structure enclosing a space leading to said rolls for delivering said material under pressure to said valley; and a tapered hollow vane positioned within said feed means, a wedge shaped screen having openings of micron size within a range of five to 1000 microns enclosing said vane, said screen projecting through said defined plane with said wedge shape pointed toward said nip between said rolls to define with said vane a substantially continuous taper toward said nip for guiding said material to brush over said vane and said screen while being directed to said nip, said vane and said screen defining an escape passageway for air squeezed from said material by said rolls.

3. A roller mill for making sheet and flake products from pressurized material having air entrained therewith comprising: a pair of juxtapositioned rolls cooperable to compact material fed therebetween, said rolls forming a feed valley and nip therebetween, feed means including wall structure enclosing a space leading to said rolls for delivering said material under pressure to said valley; and a tapered hollow vane positioned within said feed means, a Wedge shape screen having air permeable openings enclosing said vane, said screen being arranged with said wedge shape pointed toward said nip between said rolls to define with said vane a substantially continuous taper toward said nip for guiding said material to brush over the outer surfaces of said vane and said screen while being directed to said nip, said vane and said screen defining an air escape passageway having a pair of opposed side walls parallel to said valley and tapering away from each other in.- the direction away from said nip to define a substantially continuously expanding vent promoting outward flow of entrained air in said material.

4. A roller mill for making sheet and flake products from pressurized material having air entrained therewith comprising a pair of juxtapositioned rolls cooperable to compact material fed therebetweeni, said rolls forming a feed valley and nip therebetween, and said rolls defining 6 a plane bordering said valley and tangent each of said rolls; feed means including wall structure enclosing a space leading to said rolls for delivering said material under pressure to said valley; and a tapered hollow vane positioned within said feed means, a wedge shaped screen having air permeable openings enclosing said vane, said screen projecting through said defined plane with said wedge shape pointed toward said nip between said rolls to define with said vane a substantially continuous taper toward said nip for guiding said material to brush over said vane and said screen while being directed to said nip, said vane and said screen defining an escape passageway for air squeezed from said material by said rolls.

References Cited in the file of this patent UNITED STATES PATENTS 773,876 Lorillard Nov. 1, 1904 1,118,856 Hawk Nov. 24, 1914 1,188,323 Richardson June 20, 1916

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