AU740533B2 - A dosing device and a method for dosed feeding of grained, pelletized or granulated mass material out from a container - Google Patents

Description

Wn Go/-)01AA Wfl OO~O~di~1 rc fLNUYIUU I I A dosing device and a method for dosed feeding of grained, pelletized or granulated mass material out trom a cuiitaiiier.

The invention relates to a dosing device for feeding out doses of grained, pelletized or granulated material from a container, particularly for feeding out pelletized fish fodder from a silo.

Grained, pelletized or granulated material, in the following called pellets, is often stored in a silo, from where feed out occurs close to the bottom, while filing of new material is effected from the top of the silo. An advantage with this is that the oldest material substantially is located lowermost in the silo and becomes fed out first. The arrangement also makes it possible to utilize the gravity in an advantageous way in order to achieve controlled feed out of pellets by means of a dosing device.

A simple known dosing device comprises a flap or a hatch capable of opening and closing an outlet aperture lowermost in the silo. When the hatch is opened, pellets flow out from the silo, down into a vessel or down onto a conveyer belt below the silo. When the desired amount of pellets has been drawn off, the hatch closes the outlet aperture. The amount can often be determined with sufficient accuracy by controlling the opening time of the hatch by means of a timing de- Wn 000i1r.< O, roiuu2 F IINU98IUU0 31 vice. Better accuracy can be achieved by means of a controller receiving signals from a weight or volumetric measuring accessory, the signal value being compared to a predetermined value.

In some cases, a silo may be placed straight above the place where the dosed material is used. Examples of this technique are silos associated with simple mixing plants and siloshaped automatic fodder containers somewhat spaced above the water surface in fish vessels or fish "merds".

i0 Very often, the dosed material is to be used at a place spaced from the silo, and the dosing device is then combined with a conveyor, e.g. a conveying belt such as previously mentioned.

A much used dosing device comprises a conveying screw within a channel, where the outlet aperture of the silo opens straight into the channel, without any intermediate flap or hatch. When the conveying screw is not rotating, it efficiently prevent material from flowing out from the silo.

A rotary sluice is another dosing device very much used, comprising a shovel bringing pellets from the outlet aperture of the silo to a pipe where flowing air or liquid conveys dosed material further on.

Conveyor screws and rotary sluices are simple and robust.

Additionally, they can easily be adapted to give volumetric measure of dosed amount by counting revolutions. Moreover, the rotational speed of the conveyor screw and of the shovel may easily be changed in order to achieve desired volume rate.

WO 99129166f D IT I NIJ L 0Q/i l '1 WO 99/29166 D91'T /VUI CIQ M1fl217 113£~ In order to enable to empty a pellet silo completely, it is usual that the lowermost portion of the silo is shaped as a funnel.

Anyone versed in the art is aware of that pellet bridges may form if the funnel angle is too large. A pellet bridge results in that only pellets beneath the bridge reach the outlet aperture of the silo. A small funnel angle results in that the funnel becomes relatively high and in that the funnel volume is small.

Also, it is known to be advantageous to couple the outlet aperture of the silo to an expansion chamber having a larger lateral measure than the outlet aperture of the silo, so that the pellet mass is allowed to expand after having passed through the outlet aperture. Thus, a much used silo type opens out within a ball-shaped chamber having a substantially larger diameter than the outlet aperture of the silo. The diameter of the expansion chamber is also significantly larger than the diameter of a conveyor screw extending through the expansion chamber. By using a rotary sluice, the pellet material is allowed to expand in the shovel.

Pellet bridges occur even with a small funnel angle and expansion chamber. It is, thus, usual to provide the expansion chamber, the sluice housing or the silo wall with an inspection hatch where it is possible to reach a pellet bridge with a tool to loosen up the bridge.

A silo for pellets becomes relatively tall. First, as mentioned, it is necessary with a tall funnel and, secondly, it is an advantage to have an expansion chamber in connection with a dosing device below the outlet aperture, and these measures contribute to increase the silo height. Tall silos are, generally, a disadvantage, and a resultant point of gravity at a high level is particularly a disadvantage on board floating installations.

MELB/003839 7 80v I 9.doc 4 Silos are often placed such that it is difficult to reach the area below the silo in order to maintain the dosing device or to loosen up a pellet bridge through an inspection hatch. Technical installations beneath or immediately adjacent a silo also makes it difficult to pass a conveyor screw or conveying belt for pellets out from the silo.

Another case is that there might be a need for a need for a plurality of outlets from one silo. It is known to have several hatches or flaps side by side and, correspondingly, several conveyor belts in order to convey pellets to a plurality of places of use. Also, solutions comprising two silos having a common expansion chamber are known. Several outlets become often both space-demanding and impractical.

The object of the invention is to provide a dosing method in dosing and a dosing device where the above disadvantages have been, at least in part, alleviated.

According to one aspect, the invention provides a method for dosed feeding of grained, pelletized or granulated mass material out of a container. The method comprises the steps of, firstly, providing suction through a conveying pipeline/hose Which terminates in a mouthpiece immersed in said mass material, the mouthpiece having at least one suction opening for mass material, a number of air *°9suction openings and an outermost sleeve surrounding the mouthpiece, and the sleeve has air suction openings corresponding to the air suction openings of the mouthpiece and, secondly, displacing the sleeve between first and second end positions in which the air suction openings in the mouthpiece and in the sleeve substantially overlap each other and substantially do not overlap each other respectively, whereby in the first end position sufficient air flow is permitted through the air suction openings of the mouthpiece and sleeve such that air flow through the at least one mass material suction opening is reduced and weakened in respect of flow speed to such an extent that pellets cannot be drawn into the mouthpiece and through the conveying pipeline/hose and in the second end "4-sition the air flow velocity at the at least one mass material suction opening is MELB/003839780v 1 9.doc sufficient to cause entrainment of mass material in the air flow and thereby its removal from the container. In this manner, mass material entrainment immediately commences and ceases on rapid displacement of the sleeve between said first and second positions.

Another aspect of the invention provides a dosing device for dosed feeding of a grained, pelletized or granulated mass material out from a container. The device is based on a suction effect through a conveying pipeline/hose which terminates in a mouthpiece immersed in the mass material. The mouthpiece has at least one, relatively large mass material suction opening for the passage of mass material into the conveying pipeline/hose and a number of radially directed air suction openings. An outermost sleeve, displaceable between a first end position and a second end position, surrounds the mouthpiece and has air suction 9. openings corresponding to said air suction openings of the mouthpiece. In the first g end position, the air suction openings of the sleeve substantially overlap the air suction openings of the mouthpiece thereby substantially reducing the suction capacity through the one or more mass material suction openings of the .:oe.

mouthpiece to such an extent that air flow through the one or more mass material suction openings is insufficient to cause entrainment of mass material, and, in the second end position, the air suction openings of the sleeve substantially do not overlap the air suction openings of the mouthpiece so that the latter is completely or substantially closed, except from the at least one mass material suction 9 opening, such that air flow through the one or more mass material suction openings is sufficient to cause entrainment of the mass material.

In the following, an exemplary embodiment of the invention is disclosed; reference is made to the attached drawings, wherein: Figure 1 shows diagrammatically in side elevational view a silo having a dosing device; Figure 2 shows the dosing device, on a larger scale, in section in side view, the dosing device occupying an operative condition.

WO QQInorih r/rm rlrr\lln mn~r~ 6 rLIIINJYWJU3I Figure 3 shows the dosing device, on a larger scale, in section in side view, the dosing device occupying an inoperative condition.

In figure i, reference numeral 1 defines a dosing device placed within a silo 2 containing pellets 3.

By means of a conveying hose 4, the dosing device 1 is coupled to the suction side of a fan 5, possibly a compressor, an ejector or another apparatus suitable to create a negative pressure within the conveying hose 4.

i0 Further, the dosing device 1 is connected to a pressure air source 6 by means of a pressure air pipeline 7 through a controlled valve 8. A controller 9 is connected to the controlled valve 8 and adapted to give it signals to open or to close.

The dosing device 1 which in figure 2 is shown in operative, vertical position of use, comprises a central pipe 10 coupled to the conveying hose 4 and constitutes an extension thereof.

In the wall of the pipe 10 is formed some holes 11, admitting flows of air into the pipe 10. An axially displaceable sleeve 12 surrounding the pipe 10, is provided with holes 13 positioned in a similar pattern as the holes 11 in the pipe so that the holes 13 in the sleeve 12 can be brought to overlap the holes 11 in the pipe 10 by displacing the sleeve 12 along the pipe When the sleeve 12 occupies a first operative end position, such as shown in figure 2, the holes 13 do not overlap the holes 11. Then, negative pressure within the hose 4 and pipe results in that air and pellets flow into the pipe 10 at the open end thereof.

WO 99/29166 PCT/N098/0037 When the sleeve 12 occupies another, inoperative end position, such as shown in figure 3, the holes 13 overlap the holes 11. Then, negative pressure within the hose 4 and pipe results in that air flowing into the pipe through the holes 13,11. Air flowing into the pipe 10 at the open end thereof, attains then a too small speed in order to draw pellets 3 into the pipe A perforated screen 14 surrounds a substantial portion of the pipe 10 and prevents that surrounding pellets 3 come into contact with the sleeve 12, the screen 14 extending between a first flange 15 and a second flange 16 attached to the pipe The distance between the flanges 15, 16 is such that the flanges 15, 16 may serve as end stops for the sleeve 12. The screen 14 is made of net or perforated material having so small openings that pellets 3 cannot pass therethrough.

At its outer periphery, an annular diaphragm 17 is pressuresealingly attached to the first flange 15, at that side facing the second flange 16, by means of a ring 18 and screws, not shown. Further, the diaphragm 17 is pressure-sealingly attached to the sleeve 12 between a first disc 19 and a second disc 20 by means of screws, not shown, the second disc being pressure-sealingly attached to the sleeve 12.

By means of a nipple 21, the pressurized air pipeline 7 is connected to a gate 22 in first flange 15, so that pressurized air can be supplied between first flange 15 and the diaphragm 17.

A pretensioned spring 23 acting between second flange 16 and second disc 20, keeps the sleeve 12 in first end position, see figure 2. The sleeve 12 can be displaced against the force from the spring 23 to second end position, figure 3, through the supply of pressurized air between first flange and the diaphragm 17.

WO 99/29166 PCT/NO98/00371 Upon periodically supply of pressurized air, the sleeve 12 can be brought to alternate between first and second end position.

A strut 24 extending parallell to the pipe 10 is, at one end thereof, attached to second disc 20 and penetrates second flange 16.

Thus, the strut 24 follows the movements of the sleeve 12.

Onto the free end of the strut 24 is fastened an arm 25 substantially extending laterally of the pipe 10 at a distance from the free end of the pipe 10. The movements of the arm loosen up a possible pellet bridge which may prevent supply of pellets at the free end of the pipe Also, the sleeve 12 could of course have been adapted such that it turns between two end positions, the sleeve 12 in one end position closing the holes 11 in the pipe 10 and opening the holes 11 in the pipe 10 in the other end position.

Upon a need for several outlets from a silo 2, a plurality of dosing devices 1 are installed within the silo 2.

Claims (16)

1. A method for dosed feeding of grained, pelletized or granulated mass material out of a container, the method comprising the steps of: providing suction through a conveying pipeline/hose which terminates in a mouthpiece immersed in said mass material and having at least one suction opening for mass material and a number of air suction openings, there further being an outermost sleeve surrounding the mouthpiece, the sleeve having air suction openings corresponding to the air suction openings of the mouthpiece; and displacing the sleeve between first and second end positions in which the •air suction openings in the mouthpiece and in the sleeve substantially overlap each other and substantially do not overlap each other respectively, whereby in said first end position sufficient air flow is permitted through the air suction openings of the mouthpiece and sleeve such that air flow through said at least one mass material suction opening is reduced and weakened in respect of flow speed to such an extent that pellets cannot be drawn into the mouthpiece and through the conveying pipeline/hose, and in said second end position the air flow velocity at said at least one mass material suction opening is sufficient to cause entrainment of mass material in the air flow and thereby its removal from the container, there being immediate commencement and cessation of said mass material entrainment on rapid displacement of the sleeve between said first and second positions.

2. A method of dosed feeding according to claim 1, wherein the dosed feeding is of pelletized fish fodder.

3. A method of dosed feeding according to claims 1 or 2, wherein the container is a silo. MELB/003839780v1 9.dOc

4. A method of dosed feeding according to any one of claims 1 to 3, wherein the mouthpiece is a tubular portion.

A method for dosed feeding according to any one of claims 1 to 4 wherein the sleeve is suspended at its upper end from an annular, deformable diaphragm with an outer circumferential portion, which is fixedly attached to the mouthpiece, and an inner circumferential portion, which is fixedly attached to the sleeve, said diaphragm being expandable/collapsible to an extent corresponding to the necessary displacement distance of the sleeve, in a direction coaxial with the mouthpiece, between said first and second end positions.

6. A dosing device for dosed feeding of a grained, pelletized or granulated mass material out from a container and based on a suction effect through a e••See conveying pipeline/hose which terminates in a mouthpiece immersed in the mass material, said mouthpiece having at least one, relatively large mass material suction opening for the passage of mass material into the conveying pipeline/hose and a number of radially directed air suction openings, wherein an outermost sleeve, displaceable between a first end position and a second end position, surrounds the mouthpiece and has air suction openings corresponding to said air suction openings of the mouthpiece, wherein, in the first end position, the air suction openings of the sleeve substantially overlap the air suction openings of the mouthpiece thereby substantially reducing the suction capacity through the one or more mass material suction openings of the mouthpiece to such an extent that air flow through the one or more mass material suction openings is insufficient to cause entrainment of mass material, and, in the second end position, the air suction openings of the sleeve substantially do not overlap the air suction openings of the mouthpiece so that the latter is completely or substantially closed, except from the at least one mass material suction opening, such that air flow through the one or more mass material suction openings is sufficient to cause entrainment of the mass material. MELB/00O3839780v1 9.doc 11

7. A dosing device according to claim 6, wherein the mass material is pelletized fish fodder.

8. A dosing device according to claim 6 or 7, wherein the container is a silo.

9. A dosing device according to any on of claims 6 to 8, wherein the mouthpiece is a tubular portion.

A dosing device according to claim 9, wherein the sleeve is displaceable in the axial direction of the tubular portion.

11. A dosing device according to any one of claims 6 to 10, wherein displacement of the sleeve is actuated by an actuator.

12. A dosing device according to any one of claims 6 to 11, wherein the sleeve ~is surrounded by a screen of net, netting or other perforated plate having openings smaller than the particle size of grain, granules, pellets, etc. constituting the mass material, the screen not obstructing access of the mass material suction opening to the mass material.

13. A dosing device according to any one of claims 6 to 12, wherein the device includes a strut extending substantially axially parallel to the mouthpiece *etoe and having a lateral arm positioned adjacent the mass material suction opening.

14. A dosing device according to any one of claims 6 to 13, wherein the sleeve is suspended at its upper end from an annular, deformable diaphragm with an outer circumferential portion, which is fixedly attached to the mouthpiece, and an inner circumferential portion, which is fixedly attached to the sleeve, said diaphragm being expandable/collapsible to an extent corresponding to the necessary displacement distance of the sleeve, in a direction coaxial with the mouthpiece, between said first and second end positions.

MELB/003839780v19.doc 12 A method for dosed feeding substantially as described herein with reference to the accompanying drawings.

16. A dosed feeding device substantially as described herein with reference to the accompany drawings. Freehills Carter Smith Beadle Patent Attorneys for the Applicant: Akva AS 10 September 2001