WO2000006962A1

WO2000006962A1 - Device and method for drying liquid-containing substances such as for instance manure

Info

Publication number: WO2000006962A1
Application number: PCT/NL1999/000458
Authority: WO
Inventors: Petrus Johannes Henricus De Bruin
Original assignee: Peter De Bruin Holding B.V.
Priority date: 1998-07-29
Filing date: 1999-07-19
Publication date: 2000-02-10
Also published as: AU5198599A; NL1009764C2

Abstract

The invention relates to a device for drying liquid-containing substances such as for instance manure, comprising: a number of substantially horizontally placed parallel beams (1, 2, 3, 4), drive means (5, 6, 17, 18) for rotating translation of at least two of the beams, and supply means (7, 9) for gas which connect onto the parallel beams. The invention also relates to a method of drying liquid-containing substances such as for instance manure.

Description

Device and method for drying liquid-containing substances such as for instance manure

The invention relates to a device and method for drying liquid-containing substances such as for instance manure. Particularly envisaged here is poultry manure, pig manure or other manure which has already had liquid fraction removed, although it is also possible to dry other substances such as sludge, compost, offal, soil, vegetable waste, grass, wood shavings and so on.

In an existing method for drying manure with a liquid manure fraction removed, this manure is placed on a conveyor belt which takes an air-permeable form. During transport of the manure over the belt air is carried simultaneously through the conveyor belt and the manure. This method of drying manure is found to function in practice but has the drawback that the air-permeable conveyor belts are relatively susceptible to wear. Another drawback is the limited strength of the conveyor belt, whereby in practice only a manure layer of a maximum height of about 10 cm can be placed on the belt. In order to nevertheless obtain sufficient drying capacity, this prior art drying device must take a multiple form. This means in practice that setups are realized wherein up to 16 conveyor belts are placed a short distance one above another. This method of drying manure is therefore comparatively costly, requires much space and is prone to breakdown. Yet another drawback is the relatively short path along which the supplied drying air comes in contact with the manure. The drying air is found in practice to be by no means saturated after passing through the manure. Drying the manure in this manner is thereby relatively energy-intensive.

The present invention has for its object to provide an improved method and device for drying liquid-containing substances such as for instance manure, whereby with less energy and with a comparatively inexpensive device a better drying result can be obtained while retaining the advantages according to the above described prior art.

The present invention provides for this purpose a device of the type stated in the preamble, comprising:

- a number of substantially horizontally placed parallel beams,

- drive means for rotating translation of at least two of the beams, and - supply means for gas which connect onto the parallel beams. The parallel beams of the drying device are preferably placed adjacently and the drive means preferably cause at least two of the beams to rotate out of phase. Such a device can take a robust form such that the substance for drying, such as for instance manure, can be placed on the beams in a very thick layer (up to for instance a thickness of 2 metres) without the danger of damage to the device. The advantage hereof is that the device has a large processing capacity. An additional advantage of a substance layer of great thickness is that the gas (in practice usually air) which is carried through the substance must cover a relatively long path through the substance. The gas will thereby be more saturated than when the gas can cover only a short path through the substance.

The consequence hereof is that the device operates very efficiently. The rotating translation of at least two of the beams will displace the manure over the device, wherein the transporting speed can be adjusted by adjusting the rotation speed. In addition to transport by means of the rotating translation, this movement of the beams also has the advantage that the substance is turned over instead of being transported as a homogeneous layer. Turning of the substance during transport and drying has a very favourable effect on the drying process, since the gas will continually penetrate the manure along different paths, thus resulting in an improved drying. In addition, the turning has an advantageous effect on the structure of the dried substance, such as for instance manure. This is then finely divided and therefore highly suitable for further processing. The supply of gas also largely prevents portions of substance dropping downward between the carriers. Another advantage of turning the substance during transport is that this enables improved composting. The favourable effect on both the drying process and the composting process is partly a result of the fact that the substance is loosened at the bottom, precisely at the location where there is the greatest tendency to compact. Having the beams adjoin parallel to each other can prevent manure falling through between beams and dropping off the transporting surface formed by the beams. Out-of-phase rotation of the beams is desirable from the viewpoint of both transport and mixing of the substance during transport.

In a preferred embodiment the device comprises a plurality of beams, the two outer beams of which translate rotatingly in counter-phase to the middle beam(s). The beams will thus move such that at a determined moment they will display a "peak" shape in cross-section perpendicularly of the longitudinal direction of the beams. A part of the manure will herein be urged out of the centre to the lower-lying sides. Some time later the position of the beams will be changed such that they display a "valley" shape in cross-section perpendicularly of the longitudinal direction thereof. A part of the substance will herein be urged away from the higher-lying outer beams in the direction of the middle beam(s). The advantage hereof is that the substance will be displaced relatively considerably in directions other than the transporting direction. This is desirable for a good drying and so as to obtain dried substance, such as for instance manure, with a fine structure. Other patterns of movement for the beams can of course also be envisaged. Examples hereof are for instance waves running in cross-section perpendicularly of the longitudinal direction of the beams.

In a preferred embodiment the drive means comprise at least one rotating crankshaft, which crankshaft connects by means of arms to the separate beams. Through driving one or more of such crankshafts the beams are movable in rotatably translating manner.

The construction of crankshaft with crank arms is relatively simple and provides the additional option of for instance adjusting the stroke length if the length of the crank arms is also adjustable. An important additional advantage is that one or more crankshafts can be driven by means of a single drive motor, which implies that many beams can be driven with one simple drive motor. This considerably limits the costs required for drive means.

In a preferred embodiment a single beam is supported at a plurality of positions for rotating translation. Depending on the application it is possible to provide the device with a length of many tens of metres. Such a device can thus be placed for instance over the whole length of a stall or other building, wherein manure for drying is placed on the beams on one side and dried manure can be taken off the beams on the opposite side. In another variant the device can be applied in a mushroom farm for displacing, carrying and aerating compost with the option of realizing very long mushroom racks. In a preferred embodiment the outlets of the supply means for gas can be located between the beams and/or can consist of apertures in the beams. When outlets are placed between the beams the gas displacement can be utilized to prevent substance penetrating between the beams. A very advantageous construction consists of the beams being provided with outlets.

In order to prevent substance falling from the surface formed by the beams, the outer beams preferably connect onto standing side walls.

In yet another preferred embodiment supply means for a liquid fraction, such as for instance liquid manure, are disposed above the beams. The supply means can for instance consist of spray nozzles and/or injectors. During the drying process a liquid fraction can thus be added to the already partly or wholly dried substance. The advantage hereof is that the liquid fraction is hereby also processed using the device. Another significant advantage is that feeding of a liquid fraction such as a manure fraction results in an improved structure of the dried substance. Dried manure to which liquid manure fraction has been added one or more times (for instance up to ten times) will moreover contain a higher content of fertilizers. Also when the device is applied in for instance plant or culture trays, a desired environment can thus be realized of soil or compost. As injectors can be envisaged for instance drainage pipes assembled with the device.

The invention also provides a method of drying substances such as for instance manure, by displacing the substance for drying over a conveyor, wherein the mutual cohesion of a layer of substance is changed during the transport and the substance is simultaneously aerated. The mutual cohesion of the substance for drying is preferably changed herein by separately moving the carrying elements independently of each other. This is possible for instance by out-of-phase rotating translation of the individual carrying elements. The advantages of these methods are already described above with reference to the device according to the invention with which the method can be realized. The most important advantages are that transport is linked to turning of the substance for drying, whereby an improved drying occurs and dried substance with a fine structure is created. In addition, this method can be performed very efficiently.

In a preferred method, during drying of the substance such as for instance manure, a liquid fraction such as a manure fraction is added at least once to the substance for drying. This is possible for instance by injecting the liquid fraction into the substance for drying. Not only a relatively dry fraction but also a liquid fraction is thus processed. An additional advantage is that resulting dried manure contains a relatively high fertilizer content.

The present invention will be further elucidated with reference to the non-limitative embodiments shown in the following figures. Herein: fig. la shows a cross-section through a part of the drying device according to the invention, fig. lb shows a side view of a schematic representation of the drying device shown in fig. la, fig. 2a shows a top view of a number of beams which form part of the drying device shown in fig. la and lb, fig. 2b shows a top view of a part of a beam with a form differing from that of the beams shown in fig. 2a, fig. 2c shows a cross-section through the beam of fig. 2b, fig. 3 shows a cross-section through an embodiment of the drying device according to the invention, fig. 4a shows a cross-section through a modified embodiment of the drying device according to the invention loaded with manure, and fig. 4b shows a cross-section through the drying device shown in fig. 4a in a different position.

Fig. la shows a cross-section through a part of a drying device perpendicularly of four beams 1, 2, 3, 4. These latter connect by means of crank arms 5 onto a crankshaft 6 and through rotation of crankshaft 6 the beams 1, 3 will move out of phase with beams 2, 4. This is elucidated by means of respective arrows PI and P2. Fig. lb shows a side view of two crankshafts 6 onto which engage crank arms 5. By rotating crankshafts 6 as according to arrows P3, beams 1, 2, 3, 4 (of which only beams 3 and 4 are shown in this figure) will move in rotating translation. When for instance manure is placed on beams 1, 2, 3, 4, it will move to the right in fig. lb depending on the rotation speed of crankshaft 6.

Fig. 2a shows a top view of five beams 1, 2, 3, 4, 12 which are provided with apertures 7 for passage of an aerating gas. For this purpose apertures 7 can be connected to a fan which blows air, such as for instance stall air or outside air, through apertures 7. It should also be noted here that it is possible to treat the gas before it is blown through apertures 7. It is possible to envisage herein for instance heating and/or drying of the gas.

Fig. 2b shows a top view of an alternatively embodied beam 8 which is provided with protruding parts 9. These protruding parts 9 of beam 8 are also shown in fig. 2c, wherein is shown that apertures are arranged in each case between protruding parts 9 and a base surface 10 of beam 8 for passage of gases. This is indicated by means of arrows P4. Protruding parts 9 enhance the transporting quality of beam 8. Protruding parts 9 also prevent substance falling downward through beam 8.

Fig. 3 shows a cross-section through a drying device 11 in which the parts corresponding with the foregoing figures are designated with the same reference numerals. Drying device 11 contains six adjacent beams 1, 2, 3, 4, 12, 13 which are connected by means of crank arms 5 to crankshaft 6. This latter is carried by bearings 14 which are supported by frame beams 15. In order to prevent the substance placed on beams 1, 2, 3, 4, 12, 13 falling sideways from outer beams 1, 13, standing side walls 16 are provided, at a short distance from which the outer beams 1, 13 move reciprocally. To bring about rotation of crankshaft 6 a drive motor 17 is coupled via a transmission 18 to the shaft 6. It is of course also possible to drive crankshaft 6 via a gear or chain transmission. Fig. 4a shows a drying device 19 which resembles drying device 11 in fig. 3 but has a crankshaft 20 which differs from that of fig. 3. The construction of crankshaft 20 is such that the middle beams 3, 4 move wholly out of phase with outer beams 1, 13. Conversely, intermediate beams 2, 12 move in intermediate phase relative to inner beams 3, 4 and outer beams 1, 13. In a position of crankshaft 20 as shown in fig. 4a, a

"peak" shape will thus be taken on by the beams. Manure 21 lying on beams 1, 2, 3, 4, 12, 13 will hereby tend to move as according to arrows P5 from the inside, i.e. from close to beams 3, 4, to the outside, i.e. to beams 1, 13.

Fig. 4b shows drying device 19 in a position in which crankshaft 20 is rotated 180° relative to the position shown in fig. 4a. Here is clearly shown that the inner beams 3, 4 are now the beams located in the lowest position while outer beams 1, 13 are the highest placed beams. Here also the intermediate beams 2, 12 are situated in intermediate phase. The thus obtained "valley" shape causes the manure 21 to tend to move as according to arrows P6 from the outside to the inside. In drying device 19 the manure 21 will be displaced relatively strongly in sideward direction.

Although the invention is elucidated with reference to only a few embodiments, it will be apparent to all that the invention is by no means limited to the described and shown embodiments. On the contrary, many variations are still possible for the skilled person within the scope of the invention. It is thus possible for instance to stack a number of drying devices 11, 19, i.e. place them one above another. In addition, no substructure is shown of any of the drying devices 11, 19. Supply means for gas must be accommodated herein, for instance fans which can bring a pressure chamber under beams 1, 2, 3, 4, 12, 13 to overpressure, whereby gas is blown into manure 21. It is also possible to incorporate a conveyor belt in such a substructure for discharge of dust and possible other contaminants which fall downward between beams 1, 2, 3, 4, 12, 13 or through apertures 7. Drying device 11, 19 can also be used to dry and/or transport sludge, sand, grass, grain, offal, a liquid-containing paper substance of for instance waste paper, water and lye.

Claims

1. Device for drying liquid-containing substances such as for instance manure, comprising: - a number of substantially horizontally placed parallel beams,

- drive means for rotating translation of at least two of the beams, and

- supply means for gas which connect onto the parallel beams.

2. Drying device as claimed in claim 1, wherein the parallel beams are placed adjacently.

3. Drying device as claimed in claim 1 or 2, wherein the drive means cause at least two of the beams to rotate out of phase.

4. Drying device as claimed in claim 3, comprising a plurality of beams, the two outer beams of which translate rotatingly in counter-phase to the middle beam(s).

5. Drying device as claimed in any of the foregoing claims, wherein the drive means comprise at least one rotating crankshaft, which crankshaft connects by means of crank arms to the separate beams.

6. Drying device as claimed in any of the foregoing claims, wherein a single beam is supported at a plurality of positions for rotating translation.

7. Drying device as claimed in any of the foregoing claims, wherein the outlets of the supply means for gas are located between the beams.

8. Drying device as claimed in any of the foregoing claims, wherein the outlets of the supply means for gas consist of apertures in the beams.

9. Drying device as claimed in any of the foregoing claims, wherein the outer beams in longitudinal direction connect onto standing side walls.

10. Drying device as claimed in any of the foregoing claims, wherein supply means for a liquid fraction are disposed above the beams.

11. Drying device as claimed in claim 10, wherein the supply means for a liquid fraction, such as for instance a liquid manure fraction, comprise spray nozzles.

12. Drying device as claimed in any of the foregoing claims, comprising supply means for a liquid fraction which contain injectors.

13. Method of drying liquid-containing substances such as for instance manure, by displacing the substance for drying over a conveyor, wherein the mutual cohesion of a layer of substance is changed during the transport and the substance is simultaneously aerated.

14. Method as claimed in claim 13, wherein the mutual cohesion of the substance for drying is changed by separately moving the carrying elements independently of each other.

15. Method as claimed in claim 14, wherein the individual carrying elements are rotatingly translated out of phase.

16. Method as claimed in either of the claims 14-15, wherein during drying of the substance a liquid fraction is added at least once to the substance for drying.

17. Method as claimed in claim 16, wherein the liquid fraction is injected into the substance for drying.