US2931500A

US2931500A - Pneumatic grain cleaner

Info

Publication number: US2931500A
Application number: US667336A
Authority: US
Inventors: Andren Ingmar Karl Linus; Ridderstrom Gustav Folk Ingmar
Original assignee: Linde Maskiner AB
Current assignee: Linde Maskiner AB
Priority date: 1956-06-29
Filing date: 1957-06-24
Publication date: 1960-04-05
Anticipated expiration: 1977-04-05

Description

April 5, 1960 I. K. ANDREN ET AL 2,931,500

PNEUMATIC GRAIN CLEANER Filed June 24, 1957 2 Sheets-Sheet 1 INVENTORS K. L. ANDRE/v 6. E R/DDERSTROM ATTORNEYS April 1960 l. K. L. ANDREN EI'AL 2,931,500

PNEUMATIC GRAIN CLEANER 2 sheets-sheet 2 Filed June 24, 1957 INVENTORS mm R 0.1 S R n mm A'I'TORNEYJ United States Patent PNEUMATIC GRAIN CLEANER Ingmar Karl Linus Andrn and Gustav Folke Ingmar Ridderstriim, Lindesberg, Sweden, assignors' to Aktiebolaget Linde Maskiner, Lindesberg, Sweden, :1 corporation of Sweden Application June 24, 1957, Serial No. 667,336 Claims priority, application Sweden June 29, 1956 1 Claim. (Cl. 209-139) The present invention relates broadly to thev art of cleaning machines, particularly those utilized for cleaning seed, grain and the like in which an air current is employed to effect the cleaning and to separate impurities such as husks and other particles lighter in weight than the particles being cleaned.

Thus, the invention relates to a seed or grain cleaner in which a gaseous medium such as an air current is forced to flow in a given direction and the material to be cleaned such as seed or grain is introduced into the air current so that particles or impurities of light weight are entrained in the air current and removed from the seed or grain being cleaned, which due to its weight falls by gravity effect counter current to the direction of flow of the air current.

It is, therefore, an object of the present invention to provide, in a grain or seed cleaning machine, a unique and simple arrangement of air channels and a method of effecting separation of impurities from grain or seed to be cleaned which combines a simple and effective channeling of the separating air current to attain a maximum efficiency.

In grain cleaning machines in accordance with the invention, the vertically disposed or updraft air channels are for the most part of rectangular or oval horizontal cross section and are so constructed as to width in their major dimension that a portion of the air current flowing therethrough is not utilized for cleaning purposes but is exhausted in any suitable manner away from the cleaning machine so that the feed path of seed or grain to be cleaned has less transverse dimensions than the air channel whereby more effective cleaning is obtained.

In grain cleaning machines utilizing what can be termed an updraft air current, two general systems of establishing the air current are known, namely one in which a fan induces an air current through the channel by suction and the other in which the fan, centrifugal blower of the like is arranged below the path of fiow of the material to be cleaned so that the air current is blown through the said material. The air channels are generally constructed so as to be rectangular in cross section with the short sides being only a fraction of the length of the long sides. Constructing channels in this form has the effect that if an air current is blown or drawn by a fan through the channel, the air velocity is not the same throughout the entire cross section of the channel. This is because skin friction in the ends of the channel adjacent the short sides reduces air velocity in these portions of the channel. In other words, there is a large frictional resistance that the moving air has to overcome in the opposite ends of the channel and in the corn rs thereof, plus the fact that the impeller or fan usually has a smaller or narrower communication with the air channel so that it operates more effectively in the central portion of the channel than at the lateral edges. Therefore, in conventional cleaning machine constructions, wherein the grain or seeds to be cleaned are fed fan means are located above the feed means.

2,931,500 Patented Apr; 5, 1960 into the updraft air channel throughout a path coextensive in width with the width of the channel an uneven cleaning action occurs.

It has been ascertained that in an updraft air channel construction for a grain cleaning machine having a channel or conduit measuring 1.5 meters along its long side and .08 meter alongits short side that it is only at a location at 0.2 meter inwards from the opposite short sides toward the center of the channel that the air velocity attains the same value as exists in the central portion of the channel. Consequently, there is attained a uniform or even'suction or blast effect from a fan through the separating screen associated with such channel for an extent of only a section of 1.1 meters of the shafts total width of 1.5 meters. In other words, adjacent the corners of the air channel and the screen associated therewith, the cleaning action is not as effective as it is in the mid portion of the air channel so that certain impurities of intermediate weight can fall down with the cleaned grain, seed or the like.

It is therefore an object of the invention to provide in a machine for cleaning grain or the like material a combination of wall means that defines an upwardly directed channel of uniform cross-sectional shape throughout its effective extent and having major and minor dimensions, with the major dimension being substantially greater than the minor dimension. The channel has an open lower end and fan means at least coextensive in width with the major dimension of the channel are provided for establishing an upwardly flowing air current through the channel. Feed means are located adjacent the lower open end for introducing material to be cleaned and the Further,

' the feed means have an extent in a direction parallel to the major dimension of the channel at the location where the material being introduced comes under the influence of the air current that is less than the major dimension of the channel, so as to define opposite ends which respectively terminate inwardly of the opposite narrow ends of the channel a distance such that the respective opposite marginal edges of the stream of introduced material are within the cross-sectional area of the channel wherein due to the uniformity of the cross-sectional shape of the channel and the width of the fan means there exists substantially uniform air velocity.

Further and more specific objects of the invention will be apparent from the following description taken in connection with the accompanying drawings in which:

Figure 1 is a diagrammatic view partly in side elevation and partly in vertical section illustrating a vertically disposed or updraft air channel having an open lower end and with a feed screen disposed beneath the same and in which the air current is induced from the upper portion of the channel and the material to be cleaned having been screened before its introduction into the air current,

Figure 2 is a top plan view of the arrangement of Figre 1 with a portion of this view constituting a horizontal section taken along line 22 of Figure 1,

Figure 3 is a view similar to Figure l but illustrating an arrangement for cleaning grain or a like material in which such material is fed into the air channel from a bin and is screened after being air cleaned, and

Figure 4 is a top plan view of Figure 3 illustrating the extension of the air channel beyond the side edges of the screen and the feed bin.

As indicated above, the invention is not to be limited to arrangements in which the grain or other material to be fed is introduced directly into the vertically disposed or updraft air channel of uniform cross-sectional shape intermediate the ends thereof. Thus, Figures 1 and 2 ili V v 31932 lustrate an inclined screen S over which the material to be screened and cleaned flows by gravity to pass beneath the open lower end of a vertically disposed updraft air channel of rectangular form having its long walls A extending transversely of the screen and itsshort end walls B and C extending parallel to the lateral edges of the screen. As shown in Figure 2 the Width of the screen S is less than the distance between the end walls B and C of the air channel. The screen S is dimensioned and supported relative to the air channel so that an equal area of air channel projects beyond the opposite side edges of the screen. Suitable legs such as at L support the screen. A suction fan means including a housing H and a fan F, which as shown in Figure 2 has a width coextensive with the extent of walls A,'is incorporated with an upper part of theair channel; The fan is driven by any suitable drive connected to pulley P. Asshown, the fanmeans is located above the screen or feed means whereby in operation the grain passing over the screen S is preliminarily screened so that smaller impurities fall through the screen and unscreened material is then subjected to the induced air current flowing upwardly through the air channel. The spaces X and Y, Figure 2, at the opposite ends of the air channel are those areas where the air velocity is lower than in the portion of the air channel overlying the screen. in that portion of the air channel overlying the screen the air velocity is uniform so that lightweight impurities, that is, those lighter than the grain G to be cleaned are drawn oil" through the air channel with the full extent of the flow of material moving along the screen being subjected to uniform air velocity for effective cleaning.

Figure 3 illustrates an arrangement in which a feed'bin Fe is attached to one side wall A of the air channel, a roller D acts as a discharge roller to discharge material G to be cleaned from the bin beneath the partition 1'. The

material after passing over the roiler strlkesthe inclined bottom walls of the bin and flows through a slot E in the wall A. The slot is disposed. above the bottom of the vertically disposed air channel or conduit and the major dimensions of the channel are in excess of the screen S and bin Pa. The material to be cleaned is subjected to an induced air current by a fan means including a housing H and a fan F, driven by a suitable drive to a pulley P. The housing and fan are operatively associated with the air channel similarly to the relationship of Figure l at a location above the bin so as to suck air upwardly through the open lower end of the air channel. The heavier particles fall through the air stream and land on the screen 5 wherein any further small size though heavy impurities pass through the screen while the grain, seed or other material to be recovered flows down the screen S for col ec E sure 4i st ates e ex sion a d Y of the air channel that project beyond the opposite side walls of the bin Pe so that the width of the falling curtain of particles to be cleanedis restricted to an extent of the air channel that is intermediate the ends thereof, whereby the low air velocity chest that exists in areas X and Y are'n'ot applied to thecleaning or the material and the entire stream of material is subjected to substantially uniform air velocity.

Whilein the" attached drawings the screen bin and updraft all channels are rectangular in form, it is believed clear that other cross sectional shapes are applicable, such as oval'a'ir channels and different shaped screens and ia 9 le s as he. Pr p s of h nve n i c ing restricting the width of the path of flow of material to be cleaned to dimensions'les's than the major dimensions of the air channel along its inlet side is included.

What is claimed is:

In a machine for cleaning grain or the like material, the combination of with means defining an upwardly di rected channel of uniform cross-sectional shape throughout its effective extent and having major and minor dimensions, with the major dimension being substantially greater than the minor dimension, said channel having an open lower end, fan means at least coextensive in width with the major dimension of the channel for establishing an upwardly flowing air current therethrough, feed means adjacent the open lower end of the channel for introducing material to be cleaned into said air current from a direction that is transverse of the major dimen-r sion of the channel, whereby lightweight particles of material are conveyed upwardly through the channel, said fan being above said means, and said feed means for introducing material having an extent in a direction parallel to the major dimension of the channel at the location where the material being introduced comes under the influence of the air current that is less than the major dimension of the channel, so as to define opposite ends which respectively terminate inwardly of the opposite narrow ends of the channel a distance such that the respective opposite marginal edges of the stream of introduced material are within the cross-sectional area of the channel wherein dueto the uniformity of the cross-sectional shape of the channel and the Width of the fan, there exists substantially uniform air velocity.