WO1996036208A1

WO1996036208A1 - Separating and sequencing apparatus

Info

Publication number: WO1996036208A1
Application number: PCT/GB1996/001148
Authority: WO
Inventors: Mark Newland; Stuart Gale; Stephen Bishton
Original assignee: Semelab Plc; Suttons Seeds (Holdings) Limited
Priority date: 1995-05-16
Filing date: 1996-05-14
Publication date: 1996-11-21
Also published as: GB2301787B; GB2301787A; GB2328051B; GB9822544D0; GB2328051A; EP0828414A1; GB9509853D0

Abstract

Apparatus for separating and sequencing individual articles, for example seeds, comprises a perforated drum (3) which in use is rotated in the direction of the arrow (4) by a motor (5). The surface of the drum passes in sequence over a first chamber (7) in which a vacuum is maintained and a second chamber (8) in which a super-atmospheric pressure is maintained. A bulk supply of articles to be sorted is maintained in a trough (12) and individual articles are removed from the bulk supply by being attracted against the perforations by the vacuum existing in the first chamber. The perforations come into register with the second chamber (8) one at a time so that a sequence of individual articles is formed in chute (15). Counting means are provided to count the individual articles. The counting means may include means of determining the size of individual articles and means for comparing the measured size with acceptable size standards so that articles falling outside of acceptable standards are not counted. Fluorescence and/or colour detectors may also be included to determine whether or not articles have acceptable characteristics. The invention is particularly useful for the counting and packaging of seeds.

Description

SEPARATING AND SEQUENCING APPARATUS

This invention relates to separating and sequencing apparatus, that is to say apparatus for receiving a bulk supply of articles and separating those articles into a sequence of individual articles. The apparatus of the preferred embodiment of the invention preferably has associated therewith counting and batching apparatus which receives the sequence of individual articles and batches those articles into groups of a specified size. The batched groups may then be packaged in conventional packaging apparatus preparatory to, for example, retail sale.

Separating of a bulk supply of articles into a sequence of individual articles is a well known technique and many machines have been designed to perform this function. Whilst existing machines are satisfactory for many products, no existing machine is able satisfactorily to deal with small and irregularly shaped articles such as, for example, some seeds. The problem of separating and sequencing seeds is aggravated by the fact that many seeds have a generally thin disc like shape with the result that when viewed from one direction the maximum dimension of a seed is substantially greater than when viewed in another direction, and by the fact that seeds often have sticky or fur-like coatings which tend to resist separation of seeds from each other. Many of the most difficult seeds to count are relatively expensive, and for retail sale, must be packaged in containers holding relatively small numbers of seeds. In order to fulfil legislative requirements and/or customer wishes the number of seeds within a packet must be specified and accordingly each packet must contain a small but accurately defined number of seeds. No machine of the prior art is capable of effecting separating and sequencing of such seeds preparatory to automated counting and batching of the seeds. As a result, most seeds are counted volumetrically prior to packaging. This process is prone to inaccuracy.

The preferred embodiment of the present invention provides a separating and sequencing apparatus capable of receiving a bulk supply of seeds and separating those seeds into a sequence of individual seeds. By suitable choice of the operating parameters and component dimensions of the machine, substantially the entire range of seeds required for retail sale can be handled by the preferred embodiment of the present invention.

It should be appreciated that whilst the preferred embodiment of the present invention is particularly intended for the separating and sequencing of seeds, the present invention is of more general applicability and may be used with advantage in the separating and sequencing of many other products.

Having achieved a sequence of individual articles it is often necessary to count the articles in that sequence and batch the counted articles for packaging. The preferred embodiment of the present invention has associated therewith a counting and batching apparatus for performing this function. In addition to counting and batching the sequence of individual articles, the counting and batching apparatus of the preferred embodiment of the present invention incorporates means for detecting and for discarding articles which do not fulfil specified dimensional criteria for the articles being handled. Accordingly, in addition to counting and batching the articles of interest, the counting and batching apparatus of the preferred embodiment rejects foreign bodies and damaged or over/under sized articles.

According to one aspect of the present invention a separating and sequencing apparatus comprises: a movable perforated member; means defining adjacent first and second chambers over which the perforated member, in use, moves; means for drawing air from the first chamber to create a vacuum therein so that air will be drawn through those perforations of the perforated member which, at any moment, are in register with the first chamber; means for supplying air to the second chamber to pressurize the second chamber so that air will flow from the second chamber outwardly through those perforations of the perforated member which, at any moment, are in register with the second chamber; and means for maintaining bulk supply of articles to be separated on the surface of the perforated member adjacent the leading end of the first chamber; wherein the perforations are arranged on the perforated member such that the leading edges of the perforations, in the direction of movement of the perforated member, come into register with the second chamber one at a time.

In use, because a bulk supply of articles is maintained on the surface of the perforated member adjacent the leading edge of the first chamber, individual articles will be held against the perforations in the zone of the bulk supply by the vacuum in the underlying first chamber. These items will be carried along with the perforated member and will thereby be separated from the bulk supply. As the leading edge of each perforation comes into register with the second chamber air will be blown outwardly through the perforation to eject the article overlying the perforation. Because the perforations come into register with the second chamber one at a time, the articles will be ejected from the surface of the perforated member one at a time and will accordingly form a sequence of individual articles. The sequence can be fed into a chute which will direct the articles into a relatively narrow passageway. The spacing between individual articles within the sequence depends on the number of perforations across the width of the perforated member, the displacement of the leading edges of the perforations relative to each other in the direction of movement of the perforated member, and on the speed of movement of the perforated member.

In a particularly preferred embodiment of the invention the perforated member is in the form of a perforated drum. Obviously, the size of perforations on the perforated member must be selected in light of the size of articles to be sorted. Somewhat surprisingly, it has been found in the case of seeds only a few different sizes of perforations will cover substantially the full range of seeds handled by a commercial seedsman. Thus, by having several apparatus of the present invention a seedsman may cover substantially the full range of seeds he wishes to sell. In the alternative, a single machine may be provided with a plurality interchangeable perforated members so that by selection of an appropriate perforated member the • particular seed to be sorted may be handled.

In the case of some seeds (for example large substantially spherical seeds such a peas) each perforation will substantially always pick up one seed only. In other words, there is very little possibility that any one perforation will pick up two seeds and there is very little possibility that any perforation will pick up no seeds at all. For many seeds, however, there is a danger that, depending on the orientation of the seeds, either no seeds will be picked up by a particular perforation, or more than one seed may be picked up by a particular perforation.

To guard against the possibility that more than one seed is picked up by a particular perforation there is preferably provided, downstream of the box supply in the direction of movement of the perforated member, means for removing from the surface of the perforated member seeds which are not firmly held on the surface of the perforated member. In general, if two seeds have been picked up by a single perforation neither seed will be held firmly and accordingly the means for removing seeds not held firmly will either remove both seeds, or will remove one seed allowing the other seed to move into firm engagement with the perforation. In the preferred embodiment, the means for removing seeds not firmly held is an air knife.

In the preferred embodiment of the invention the means for maintaining a bulk supply of articles to be sorted comprises a roller or wiper which runs against the surface of the perforated member at a point where the perforated member is extending upwardly whereby a trough is defined between the roller and the perforated member. A bulk supply is maintained within the trough by suitable means, for example an in-feed conveyor. With this arrangement, a bulk supply can be maintained without causing damage to the articles to be sorted and without need for extremely accurate control as to the in-feed rate. Depending on the length of the packaging sequence which is being run at the particular time, it may be satisfactory to load the trough by hand and to add seeds to the trough when the bulk supply begins to run low. In the alternative, appropriate monitoring means may be provided coupled to an automatic feed device to maintain the level of articles within the trough within predetermined limits.

Preferably, the perforated member is in the form of a drum or belt which rotates continuously so that any particular portion of the surface of the perforated member, after passing over the second chamber, will move back to the beginning of the first chamber. In a particularly preferred embodiment of the invention, in the zone located downstream of the second chamber but upstream of the first chamber in the direction of rotation of the perforated member there is a third chamber which is supplied with high pressure air to effect a purging or cleaning of the perforations as they pass over the third chamber. By this means, any articles or foreign bodies which have become lodged in the perforations will be ejected before the perforations move back to the article pick up point.

In the preferred embodiment of the invention the sequence of articles moves from the separating and sequencing apparatus to a counting and batching apparatus. To this end, the sequence of articles preferably passes into a chute which directs the articles into a passageway. Counting means are provided for counting individual articles passing through the passageway. The counting means may be of any convenient type and may, for example, comprise an array of photodiodes arranged across one side of the passageway and a laser located on the other side of the passageway and arranged to produce a line of light spanning the array of photodiodes. By connecting the outputs of the photodiodes to suitable processing apparatus, the apparatus will indicate the passage of individual articles. If the pitch of the photodiodes is fine enough relative to the size of the articles the output of the photodiodes will provide information as to the dimension of the article in the direction parallel to the surface of the photodiode array. In suitable cases, as for example when the articles to be counted are spherical or substantially spherical, the control apparatus may be programmed to identify any articles which fall outside of specified dimensional parameters. Such items may be ignored for count purposes, or may be diverted from the sequence of articles by suitable means, for example by means of an air blast located downstream of the counting station. By this means foreign bodies and over/under sized articles may be rejected .

In a further embodiment of the invention two separate photodiode/laser sets may be provided located at right angles to each other in the same transverse zone of the passageway through which the articles pass. By this means, the dimensions of the article may be measured simultaneously to directions perpendicular to each other. Again, in suitable cases the apparatus may be programmed to use these two dimensional measurements to ascertain whether or not the article passing through the scanning field fulfils dimensional criteria which have been established for the articles being counted. Again, if a particular article does not fulfil these criteria it may be rejected.

Preferably, as soon as a desired count of acceptable sized items has been established means are activated for diverting the stream of articles thereby preventing further articles joining those already counted. Diversion continues on sufficiently long for the counted batch to be removed, e.g. to a packaging station. Diversion of the stream is then ceased and the count restarted. By this means, accurately counted batches may be established without waste or overfilling of the individual packages produced.

The invention will be better understood from the following description of a preferred embodiment thereof, given by way of example only, reference being had to the accompanying drawings wherein:

Figure 1 shows schematically an embodiment of separating and sequencing apparatus according to the present invention in association with an embodiment of counting and batching apparatus; and

Figure 2 is an exploded perspective view showing schematically the separating and sequencing apparatus of Figure 1.

Referring firstly to Figure 1 there is illustrated schematically a preferred embodiment of separating and sequencing apparatus 1 in accordance with the present invention located adjacent a preferred embodiment of counting and batching apparatus 2. Whilst, in general , it is envisaged that the separating and sequencing apparatus will be used in association with the counting and batching apparatus, this may not necessarily always be the case and the separating and sequencing apparatus may be used in certain circumstances independently of the counting and batching apparatus, and vice versa.

Referring firstly to the separating and sequencing apparatus 1 , the apparatus comprises a perforated drum 3 which, in use, is rotated in the direction of the arrow 4 by a motor 5. The drum surrounds a fixed hub 6 in which are defined three chambers 7,8 and 9 which immediately underlie the surface of the drum. The first chamber 7 has an annular extent indicated by the arrow 7A, the second chamber 8 has an annular extent indicated by the arrow 8 and the third chamber 9 has an annular extent indicated by the arrow 9A. It will be noted that the first and second chambers 7,8 are separated, in the direction of movement of the surface of the drum, by a relatively narrow land 14.

Suitable means, for example a pump 10, are provided by drawing air from the first chamber 7 and supplying air to the second chamber 8. Suitable means (not shown) are provided for supplying high pressure air to the third chamber 9.

At substantially the leading edge of the first chamber 7, relative to the direction of movement of the drum 3, a roller 11 is provided to run against the surface of the drum over the full width thereof. The roller preferably has a somewhat soft surface so that it conforms to the surface of the drum. The roller 11 may idle and be driven by the surface of the drum, or it may be driven by gearing coupled to the drum drive. The drum 3 and roller 11 form between them an upwardly open trough 12 in which is maintained a bulk supply of articles to be separated, for example seeds. The bulk supply is maintained with the trough by any suitable means. It will be appreciated that the trough is closed, at either end thereof, by suitable end plates to prevent the bulk supply from escaping.

In use, as the drum rotates the perforations in the surface of the drum pass through the trough 12. Since the trough 12 overlies the leading end of the first chamber 7 air will be drawn inwardly through the perforations as they pass through the trough 12 and individual articles will accordingly be drawn against the surface of the drum at each perforation and will be held in place by the pressure differential created by the pump 10. Individual articles thus held will be removed from the bulk supply and carried along with the surface of the drum.

To ensure that each perforation has associated therewith no more than one article an air knife 13, which is supplied with pressurized air from a suitable source, is located downstream of the trough 12 but upstream of the trailing end of the first chamber. The air knife applies a blast of air to the surface of the drum to dislodge any articles not firmly held against the surface of the drum by the pressure differential. Thus, if two articles are held by any one perforation, the effect of the air knife will be to dislodge both articles, or to dislodge one of the articles allowing the other article to move into firm engagement with the surface of the drum. The effect of this arrangement is to ensure that, downstream of the air knife, no perforation holds more than one article. In practice, downstream of the air knife some perforations may hold no articles whatsoever. However, this does not adversely affect operation of the apparatus.

At the downstream end of the first chamber the surface of the drum passes over the land 14 and the perforations come into register with the pressurized second chamber 8. The arrangements of the perforation on the drum and the shape of the land 14 are coordinated such that the leading edges of the perforations come into register with the second chamber 8 one at a time. This may be arranged by offsetting the perforations relatively to each other on the drum whilst having a land 14 which is substantially parallel to the axis of rotation of the drum, or by arranging the perforations on the drum in rows parallel to the axis of the drum and suitably arranging the land 14 obliquely relative to the axis of the drum so that the perforations come into register with the second chamber one at a time. The effect of either arrangement is that the articles held will be ejected from their respective perforations by the air pressure within the second chamber one at a time. The articles will accordingly leave the surface of the drum in a sequence with no two articles leaving the surface of the drum simultaneously. The articles_. leaving the surface of the drum enter a chute 15 of the counting and batching apparatus 2.

The chute directs the sequence of articles into a relatively small passageway which is provided with a detector for detecting the presence of individual articles. In its simplest embodiment the detector may be of any suitable form and is coupled to suitable counting apparatus to establish when a desired count of articles has passed through the passageway. The counting and batching apparatus incorporates means for diverting the flow of articles in response to a desired count having been established. The diverting means may, conveniently, comprises means for applying a transverse air blast to the passageway upstream of the counting device thereby diverting the stream of articles from the counting device, the diverted articles may be recycled to the bulk supply. The counted batch of articles may then be packaged in conventional packaging apparatus schematically illustrated at 16. Once one batch has been packaged the diverting means may be inhibited and the count of a fresh batch started.

In a particularly preferred embodiment of the invention, however, the counting apparatus is capable of determining certain size characteristics of the articles passing through the passageway. To this end, the counting apparatus preferably comprises an array of detectors located side-by-side spanning one side of the passageway. The detectors are illuminated by a suitable source, for example a laser beamline generator, such that as an article passes through the passage the number of detectors masked by the article provides an indication of the dimension of the article in the direction of the array. This information can be compared to pre-set characteristics established within the counting control device to establish whether or not the article in question fulfils acceptable criteria. If the article falls outside the specified criteria the diverting means will be operated to divert that particular article from the flow of articles and it will not be counted in the count establishing means. With such an arrangement, some measure of protection against the inclusion of articles of debris or damaged or deformed articles is provided. In a particularly preferred embodiment of the invention the size of articles passing through the passageway is measured in two directions at right angles to each other and perpendicular to the axis of the passageway. The resulting two dimensional measurements are compared with acceptable standards established for the articles being counted and articles not fulfilling acceptable dimensional criteria are rejected.

If desired, one or more extra detectors may be used to detect one or more additional characteristics of the articles for comparison with an acceptable set of standard characteristics, thereby further reducing the possibility of contaminants being counted as acceptable articles. For example, in the case of seeds it is known that certain moulds which grow on decaying seeds luminesce when subjected to ultraviolet radiation. Thus, it may be desirable to incorporate an ultraviolet light source and a detector sensitive to fluorescence of seeds in the passageway in order to detect the passage of a decaying seed. The diverting apparatus may then be operated to reject the particular seed or the seed may be allowed to continue but the counting arrangement can be inhibited so that the decaying seed is not counted as a good seed. Similarly, if desired colour detection means may be provided for detecting the colour of articles passing through the passageway. Again, in the case of seeds the detection of colour will assist in the rejection of rogue seeds - i.e. seeds which are of a different species or cultivar from the bulk of seeds being counted and present as a result of contamination, or non-seed debris

The preferred embodiment of the invention is particularly useful in the packaging of seeds. Seeds from a bulk supply are fed to the trough 12 by any suitable means and are separated into a sequence of individual seeds by the separating and sequencing apparatus. The counting and batching apparatus is then effective to count and batch the seeds for packaging and provides a substantial degree of protection against the accidental inclusion of debris and damaged seeds. The counting and batching apparatus also substantially avoids the accidental inclusion of seeds of an incorrect type which have become inadvertently mixed with the seeds being packaged. It should be understood, however, that whilst the invention is particularly applicable to the packaging of seeds, it may be found useful in the packaging of many other products.

Claims

CLAIMS :

1. A separating and sequencing apparatus comprising: a movable perforated member; means defining adjacent first and second chambers over which the perforated member, in use, moves; means for drawing air from the first chamber to create a vacuum therein so that air will be drawn through those perforations of the perforated member which, at any moment, are in register with the first chamber; means for supplying air to the second chamber to pressurize the second chamber so that air will flow from the second chamber outwardly through those perforations of the perforated member which, at any moment, are in register with the second chamber; and means for maintaining bulk supply of articles to be separated on the surface of the perforated member overlying the first chamber; wherein: the perforations are arranged on the perforated member such that the leading edges of the perforations, in the direction of movement of the perforated member, come into register with the second chamber one at a time.

2. Apparatus according to Claim 1 wherein: the perforated member is in the form of a perforated drum.

3. Apparatus according to Claim 1 or Claim 2 wherein: downstream of the bulk supply in the direction of movement of the perforated member, means are provided for removing from the surface of the perforated member articles which are not firmly held on the surface of the perforated member.

4. Apparatus according to Claim 3 wherein: the means for removing articles not firmly held is an air knife.

5. Apparatus according to any preceding claim wherein: the means for maintaining a bulk supply of articles to be separated comprises a roller or wiper which runs against the surface of the perforated member at a point where the perforated member is extending upwardly whereby a trough for articles is defined between the roller and the perforated member.

6. Apparatus according to any pre^ceding claim wherein: in the zone located downstream of the second chamber but upstream of the first chamber in the direction of rotation of the perforated member there is a third chamber which is supplied with high pressure air to effect a purging or cleaning of the perforations as they pass over the third chamber.

7. The separating and sequencing apparatus according to any preceding claim in combination with a counting and batching apparatus, the combination comprising a chute which directs the articles from the separating and sequencing apparatus into a passageway, and counting means for counting individual articles passing through the passageway.

8. Apparatus according to Claim 7 wherein the counting means comprises: an array of photodiodes arranged across one side of the passageway: one or more lasers located on the other side of the passageway and arranged to illuminate the array of photodiodes; and processing means responsive to the outputs of the photodiodes to indicate the passage of individual articles .

9. Apparatus according to Claim 8 wherein: two separate photodiode/laser sets are provided located at right angles to each other in substantially the same transverse zone of the passageway through which the articles pass and the processing means is operative to measure the dimensions of articles passing through the transverse zone simultaneously in two directions perpendicular to each other.

10. Apparatus according to Claim 9 wherein: the processing means is programmed to use the two dimensional measurements to ascertain whether or not the article passing through the scanning field fulfils dimensional criteria which have been established for the articles being counted.

11. Apparatus according to any of Claims 7 to 10 including diverting means for diverting the stream of articles thereby preventing further articles joining those already counted.

12. Apparatus according to any of Claim 7 to 11 including one or more additional detectors to detect one or more additional characteristics of the articles for comparison with a standard set of characteristics to determine whether or not the individual articles are of an acceptable standard, the one or more additional detectors preferably comprising a fluorescence detector and/or a colour detector.