GB2151949A

GB2151949A - Worm separation equipment

Info

Publication number: GB2151949A
Application number: GB08432405A
Authority: GB
Inventors: James Stanley Price
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK
Priority date: 1983-12-29
Filing date: 1984-12-21
Publication date: 1985-07-31
Also published as: DE3446935A1; IT8454233V0; IT1179898B; GB8432405D0; IT8468285A0

Abstract

An apparatus 10 for separating worms from a worm-containing medium comprises an upwardly-moving belt 12 fed with the medium from a hopper 14. The hopper 14 and subsequent belt 18 co-operate with the upper surface 16 of conveyor belt 12 to break up lumps in the medium and the brush 20 lightly brushes the surface 16 to remove loose material from the belt 12. By this stage however, the worms in the medium will be gripping the surface 16 and they are only dislodged from the belt for discharge into a bin (not shown) when they reach the scraper 22. In an alternative embodiment 110, the separator comprises an inclined plate 114 which is vibrated to move the material past a number of endless driven wires 116 having upwardly moving runs passing through appropriate apertures in the plate. Worms in the material become draped around the upwardly moving runs of the wires and are carried upward astride the wires for removal prior to reaching the top wire-supporting roller. The substantially worm-free material sliding off the bottom end of the plate is taken away by a cross-conveyor 124. <IMAGE>

Description

SPECIFICATION Separation equipment The present invention relates to separation equipment and in particular, but not exclusively, to separation equipment for the separation of worms from a worm-containing organic medium e.g. as derived from animal and/or vegetable wastes processed in accordance with the method of UKPA 8318084 (NRDC).

The processed medium referred to above is a fine tilth of peat-like appearance which is found to be a valuable agricultural material useful as a plant food, soil conditioner or a plant growing substrate.

The worms themselves have a high protein content and when separated from the processed waste they can be used as a feed additive e.g. for fishfarming, or for pigs or poultry.

One method of separating out the worms is to sieve the worm containing medium in a cylindrical rotating sieve having graded mesh sizes which pass the peat-like medium but not the worms which are collected downstream.

An object of the invention is to provide a more effective system for separating the worms from the worm-containing medium.

According to the present invention, an apparatus for separating worms from a worm-containing medium comprises a support surface for the medium and differential take-off means for removing from the support surface substantially only either the medium and worms contaiminated with the medium or worms not contaminated in this way.

Conveniently, the differential take-off means comprises a brush or the like moving bodily relative to the support surface and effective to remove from the support surface substantially only the medium or worms contaminated with the medium.

Conveniently in this embodiment, the support surface is provided by an endless conveyor e.g. a belt or drum, and preferably the brush or the like referred to above lightly engages or nearly engages the support surface of the conveyor as it moves past the take-off means.

Conveniently, the worm-carrying surface of the conveyor has at least one segregating section upwardly inclined at an angle which is sufficiently steep to discourage or substantially prevent adhesion to said surface section of the medium or of worms contaminated with said medium but which is sufficiently shallow to allow worms substantially uncontaminated with the medium to adhere to the conveyor surface for displacement by the conveyor surface to a worm-discharge location downstream of the segregating section.

Conveniently, the conveyor takes the form of a rubber or rubber-faced belt.

Conveniently, the apparatus comprises separation means arranged downstream of the segregating section and operative to free from the conveyor surface worms clinging thereto.

Conveniently, the separation means comprises a scraper or a rotary or fixed brush or a water or air jet or a vibrator which is arranged to vibrate the relevant portion of the conveyor with sufficient force to dislodge the worms.

Conveniently, the upper surface of the conveyor is tilted sideways to an extent such as to encourage the discharge of loose medium from the lower long edge of the conveyor.

In alternative embodiments to those described above, the preferential take-off means comprises one or more endless conveyors having at least one worm-supporting run each passing upwardly through a respective aperture in the support surface.

Conveniently, in this case, drive means are provided for moving the support surface in such a way as to encourage the displacement of the medium and/or the worms towards the one or more endless conveyors.

In one such embodiment, for example, the support surface inclines downwardly to the one or more conveyors and the drive means agitates the support surface thereby to encourage displacement of the medium and/or the worms towards the one or more endless conveyors.

Conveniently, the drive means operates to agitate the support surface principally perpendicularly to the plane of the support surface.

Conveniently, where the support surface inclines as above described, then the angle of inclination lies between 20 and 30 to the horizontal.

Conveniently, in this latter case, the drive means will operate to vibrate the support surface at a frequency of between 25 and 50 cycles per second e.g. with an amplitude in the range 1 mm to 5 mm.

Conveniently, the or each endless conveyor takes the form of a wire e.g. moving at between 20 and 50 metres per minute away from the support surface.

Conveniently, the or at least some of the apertures are closed on all sides by the support surface but additionally, or alternatively, the or at least some of the apertures could be open at one side e.g. they could comprise a number of open-ended slots extending forwardly from the trailing edge of the support surface.

Conveniently, in any of the various embodiments and variations referred to above, the apparatus also includes loading means for loading the support surface with a worm-containing medium or with worms contaminated with said medium.

Conveniently, when the apparatus is to be loaded with the worm-containing medium, it includes comminution means adapted to break up lumps present in the worm-containing medium when it is first loaded on to the support surface.

The comminution means referred to above may for example be provided by a hopper for the medium a lower edge of which co-operates with the adjacent surface of the conveyor to impose shear on the medium as it is loaded on to the conveyor.

Alternatively, the comminution means may comprise a pair of contra-rotating brushes, finned rollers, slatted belts or like rotary members adapted to load the conveyor by throwing the medium on to the upper surface of the conveyor. In this case, the medium is comminuted firstly by the action of the rotary members and secondly by impact on the conveyor surface.

Alternatively, or additionally, the comminution means may comprise one or more belts or rollers or like rotary members presenting a surface adjacent to but moving relative to the upper surface of the conveyor to sandwich the worm-containing medium between the upper surface of the conveyor and the one or more rotary members thereby to break up lumps present in the medium.

Alternatively, or additionally, the comminution means may comprise one or more shear bars extending from side to side of the conveyor and optionally providing the depth control means referred to above.

Conveniently, when the apparatus is to be loaded with worm containing medium it includes depth control means for regulating the depth of the worm-containing medium on the support surface.

The invention also includes an apparatus according to the present invention when adapted for the harvesting of worms direct from a bed of the worm-containing medium.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which: Figure I shows a side view of an inclined belt segregator in accordance with a first embodiment of the present invention; Figure 2 shows a simplified side view of an inclined plate segregator in accordance with a second embodiment of the present invention; and Figure 3 shows a simp!ified end view of this second embodiment looking along the length of the plate.

Thus referring first to Figure 1 of the drawings, an apparatus 10 for separating worms from a worm-containing medium comprises an endless rubber-faced conveyor belt 12 accepting the medium from a straddle hopper 14.

The lower front edge of the hopper is spaced about two mm from the upper surface 16 of the belt and co-operates with surface 16 to provide medium-comminuting shear forces on the medium being loaded on to the belt.

Downstream of hopper 14 is a second belt 18 arranged above and moving at a different surface speed to belt 12, the adjacent faces of the two belts being spaced apart by about 2 mm and cooperating to provide further comminution of the medium.

Belt 18 is followed by a soft brush 20 extending across the width of the conveyor belt 12 and rotating in an anti-clockwise direction as viewed in the drawing so as lightly to brush surface 16.

A scraper 22 is provided at the top underside surface of the conveyor belt to dislodge worms from the surface of the belt 18 for discharge into a collector bin (not shown).

Although not depicted in the diagrammatic side view of the drawing, in fact, the conveyor belt 12 and at least the co-operating parts of items 14,18 20,22 have a slight sideways tilt e.g. 5; to encourage loose medium to fall off the belt at the brushing stage.

The optimum inclination of the belt 12 in the plane of the drawing will depend on the nature of the worm-containing medium and the material of the belt but 45 would be a typical value.

Preferably, both the inclination and the tilt of the belt are adjustable.

Alternative or additional items to those depicted in the drawing have already been discussed in general terms earlier in the application e.g. the use of one or more shear bars upstream of and/or instead of the brush 20 and the use of a brush or jet to dislodge the worms from the upper end of the belt in place of the scaper 22. Another variation already mentioned in general terms is the replacement of the hopper 14 by a loading belt from which the worm-containing medium is thrown on to the belt 12 by contra-rotating brushes or the like.

In operation of the apparatus, a typical surface speed for a belt 12 of 3 metres length is about 0.25 metres per second. Typically, belt 18 will have a lower surface moving at about 0.2 metres per second in the same direction as surface 16 and brush 20 will rotate at about 50 r.p.m. in the opposite direction to belt surface 16. A typical throughput where the conveying belt also has a width of 40 cm would be about 5 to 10 iitres per minute.

Referring now to Figure 2 of the drawings, an apparatus 110 for separating worms from a wormcontaining medium comprises a straddle hopper 11 for feeding a worm-containing medium on to an inclined metal plate 114.

The lower front edge of the hopper is preferably spaced about 2 mm from the upper surface of the plate 114 and co-operates with this surface to provide medium-containing shear forces on the medium being loaded on to the belt.

Although not apparent from the drawing, the plate114is perforated by numerous small holes (not shown) drilled through it For a plate of plan dimensions 100 cm by 100 cm, for example, there might typically be some 400 holes spaced apart equally across the width of the plate in 20 equally spaced rows.

Through each hole in the plate passes the upwardly moving run of an endless worm-extractor wire 116 the downwardly moving run of which passes to one side of the plate 114.

For convenience, only three wires 116 have been shown in the drawing although in actual fact, as above described, there will be one for each hole in the plate 114.

At the uppermost point of their travel, the wires 116 of any one row pass around a roller (120) which is driven e.g. by an electric motor, to give the desired upward motion of the worm collecting run of the wire. At their lowermost point, the same wires pass around an idling roller (122). In practice, therefore, there will be a plurality of roller pairs, one for each row of holes in the plate 114. Optionally, the holes in adjacent rows are offset slightly relative to one another to avoid tangling of the worm-extractor wires.

A drive means (not shown) is included for vibrating the plate 114 in the desired manner. One convenient drive means, for example, would be an eccentric weight vibrator but as an alternative a piston vibrator could be used, for example.

Material leaving the lower end of the plate 114, is collected by a cross-conveyor 124 which discharges it into an appropriate collection bin (not shown).

The simplified end view of Figure 3 (looking up the plate 114) shows how worms can be removed from a wire 116 by a jet of air or water from a blower 126 for discharge into a second collection bin (not shown).

Alternative or additional items to those depicted in the drawing may occur to those skilled in the art e.g. the use of a brush or scraper to dislodge the worms from the belt 116 in place of the blower 126.

Another variation would be the replacement of the hopper 112 by a loading belt from which the worm-containing medium is thrown on to the plate 114 by contra-rotating brushes or the like.

In operation of the apparatus, the drive means is actuated to vibrate the plate 114 principally perpendicularly to its own plane although if desired the drive means may be adapted to vibrate the plate substantially in this plane or in a composite e.g. loop, motion. This causes a steady stream of the worm-containing medium to flow under the front edge of the hopper and down the plate towards the wires 116.

When the medium reaches the wires 116, the worms become draped over the moving wires and are carried upward astride the wires until washed or blown off below the top roller 120 by the blower 126.

As already mentioned above, the invention also includes an apparatus for the harvesting of worms direct from a bed of the worm-containing medium.

One such embodiment, for example, might comprise the apparatus of Figure 1 or Figures 2 and 3 mounted on a gantry for movement over the upper surface of the bed. In both these cases, the hopper (14, 12) would be replaced by an appropriate endless belt loading mechanism or the like scooping up the medium from the bed and depositing it on to the lower end of belt 12.

Claims

1. An apparatus for separating worms from a worm-containing medium comprises a support surface for the medium and differential take-off means for removing from the support surface substantially only either the medium and worms contaiminated with the medium or worms not contaminated in this way.

2. An apparatus as claimed in Claim 1 in which the differential take-off means comprises a brush or the like moving bodily relative to the support surface and effective to remove from the support surface substantially only the medium or worms contaminated with the medium.

3. An apparatus as claimed in Claim 2 in which the support surface is provided by an endless conveyor.

4. An apparatus as claimed in Claim 3 in which the brush or the like lightly engages or nearly engages the support surface of the conveyor as it moves past the take-off means.

5. An apparatus as claimed in Claim 3 or Claim 4 in which the worm-carrying surface of the conveyor has at least one segregating section upwardly inclined at an angle which is sufficiently steep to discourage or substantially prevent adhesion to said surface section of the medium or of worms contaminated with said medium but which is sufficiently shallow to allow worms substantially uncontaminated with the medium to adhere to the conveyor surface for displacement by the conveyor surface to a worm-discharge location downstream of the segregating section.

6. An apparatus as claimed in any of Claims 3 to 5 in which the conveyor takes the form of a rubber or rubber-faced belt.

7. An apparatus as claimed in any of Claims 3 to 6 when including the limitations of Claim 5 comprising separation means arranged downstream of the segregating section and operative to free from the conveyor surface worms clinging thereto.

8. An apparatus as claimed in Claim 7 in which the separation means comprises a scraper or a rotary or fixed brush or a water or air jet or a vibrator which is arranged to vibrate the relevant portion of the conveyor with sufficient force to dislodge the worms.

9. An apparatus as claimed in any of Claims 3 to 8 in which the upper surface of the conveyor is tilted sideways to an extent such as to encourage the discharge of loose medium from the lower long edge of the conveyor.

10. An apparatus as claimed in Claim 1 in which the preferential take-off means comprises one or more endless conveyors having at least one worm-supporting run each passing upwardly through a respective aperture in the support surface.

11. An apparatus as claimed in Claim 10 in which drive means is provided for moving the support surface in such a way as to encourage the displacement of the medium and/or the worms towards the one or more endless conveyors.

12. An apparatus as claimed in Claim 11 in which the support surface inclines downwardly to the one or more conveyors and the drive means agitates the support surface thereby to encourage displacement of the medium and/or the worms towards the one or more endless conveyors.

13. An apparatus as claimed in any of Claims 10 to 12 in which the the drive means operates to agitate the support surface princi pally perpendicularly to the plane of the support surface.

14. An apparatus as claimed in any of Claims 10 to 13 when including the limitations of Claim 11 and in which the angle of inclination lies between 20O and 30O to the horizontal.

15. An apparatus as claimed in Claim 14 in which the drive means operates to vibrate the support surface at a frequency of between 25 and 50 cycles per second.

16. An apparatus as claimed in Claim 15 in which the drive means operates to vibrate the support surface with an amplitude in the range 1 mm to 5 mm.

17. An apparatus as claimed in any of Claims 10 to 16 in which the or each endless conveyor takes the form of a wire.

18. An apparatus as claimed in Claim 17 in which the wire is adapted to move at between 20 and 50 metres per minute away from the support surface.

19. An apparatus as claimed in any of Claims 10 to 18 in which the or at least some of the apertures are closed on all sides by the support surface.

20. An apparatus as claimed in any of Claims 10 to 19 in which the or at least some of the apertures are open at one side.

21. An apparatus as claimed in Claim 20 in which the apertures open at one side comprise a number of open-ended slots extending forwardly from the trailing edge of the support surface.

22. An apparatus as claimed in any preceding claim including loading means for loading the support surface with a worm - containing medium or with worms contaminated with said medium.

23. An apparatus as claimed in Claim 22 including comminution means adapted to break up lumps present in worm-containing medium when it is first loaded on to the support surface.

24. An apparatus as claimed in Claim 22 in which the comminution means is provided by a hopper for the medium a lower edge of which cooperates with the adjacent surface of the conveyor to impose shear on the medium as it is loaded on to the conveyor.

25. An apparatus as claimed in Claim 23 in which the comminution means comprises a pair of contra-rotating brushes, finned rollers, slatted belts or like rotary members adapated to load the conveyor by throwing the medium on to the upper surface of the conveyor, the medium being comminuted firstly by the action of the rotary members and secondly by impact on the conveyor surface.

26. An apparatus as claimed in Claim 24 or Claim 25 in which the comminution means comprises or also comprises one or more belts or rollers or like rotary members presenting a surface adjacent to but moving relative to the upper surface of the conveyor to sandwich the worm-containing medium between the upper surface of the conveyor and the one or more rotary members thereby to break up lumps present in the medium.

27. An apparatus as claimed in any of Claims 24 to 26 in which the comminution means comprises or also comprises one or more shear bars extending from side to side of the conveyor and optionally providing said depth control means.

28. An apparatus as claimed in any of Claims 22 to 27 when the including depth control means for regulating the depth of worm-containing medium on the support surface.

29. An apparatus substantially as hereinbefore described with reference to and/or as illustrated in Figure 1 of the accompanying drawings.

30. An apparatus substantially as hereinbefore described with reference to and/or as illustrated in Figure 2 and 3 of the accompanying drawings.

31. An apparatus as claimed in any preceding claim adapted for the harvesting of worms direct from a bed of the worm-containing medium.