EP1153253B1 - Chamber and installation for drying animal waste - Google Patents

Abstract

The invention concern a chamber for drying animal waste, in particular poultry manure, adapted to receive a mixture (M) of fresh waste and dry waste, the floor thereof being adapted to retain the mixture (M) while being permeable to air (A), said floor consisting of an assembly of elements (60, 60') each capable of forming means for retaining the waste and including means (T) which periodically enable to transfer outside the chamber (1) and through said floor (6) a fraction of the dry waste. The invention is characterised in that said elements consist of two series of horizontal crosspieces (60, 60') arranged along two superposed parallel planes (P1, P2), said crosspieces (60,60') being arranged such that the floor (6) contains gaps in the vertical direction, and said transfer means (T) consist of at least a sliding drawer horizontally mobile between said two planes (P1, P2) of crosspieces (T), the longitudinal movement of said drawer, capable of sweeping the entire surface of said floor from one end to the other, driving the waste accumulated on said crosspieces (60') of the lower plane (P2) such that they drop by gravity outside the chamber. The invention also concerns a drying installation equipped with such a chamber.

Description

The present invention relates to an enclosure and an installation for drying animal droppings, especially poultry droppings.

Due to their high water content, we have already proposed a large number of techniques for drying poultry droppings, the main purpose of which is to obtain a dehydrated and deodorized product, easily usable for subsequent applications. A main application is that of fertilizer.

The simplest method is to inject, inside the livestock buildings, air above the endless belt conveyors which are placed under the breeding cages and on which the droppings of the poultry. However, the air is only partially charged with humidity, due to its rapid passage in contact with the thin layer of droppings spread over the conveyors. To obtain better performance, air volumes should be used very important and ensure turbulence within it, which is very expensive in energy.

In some cases, this type of process is implemented within drying tunnels, outside livestock buildings. The major drawbacks of this type of installation resides in its size and complexity mechanical.

EP-B-0 210 196 describes a process and a installation for drying and conditioning hen manure. The process includes a stage of microbiological transformation of manure, which requires to have to carefully monitor all the parameters of the transformation, to be sure to ensure proper drying of the manure. In addition, the corresponding installation is necessarily complex and expensive.

Document US-A-2679114 relates to an apparatus and a process for processing and composting manure. The device has a conveyor that transports raw manure to the top of a silo. The bottom of silo is formed by two perforated and converging partitions between which extends a channel. At the bottom of the channel is provided a conveyor arranged in a chute. Above from the conveyor extend two parallel rotary shafts provided with blades. The rotational drive of the trees causes the transfer of part of the manure in the conveyor.

Pressurized air, possibly charged with humidity, is introduced into the mass of manure, through the lower part of the silo, to ensure its transformation. The air flows against the current with respect to the manure, which contributes to improving its drying or its transformation.

Document DE-A-2723581 relates to a method and an installation aerobic decomposition of organic solids. The installation includes a material pre-drying device, a storage enclosure and a silo for processed and dry product. This enclosure and this silo communicate by their bottom with a twin screw conveyor which provides an intimate mixture of the pre-dried product and dry product.

This mixture is then transferred to a decomposition reactor at movable bottom, via a vertical conveyor. Mixing can be selectively directed to a drying tower and the final product is stored in the aforementioned silo.

It should be noted that the movable floor is, as in the document previous, consisting of a set of rotating shafts whose periphery is provided fingers or blades.

This type of mobile and breathable bottom presents serious disadvantages.

Indeed, when the dried excrement agglomerates in the form of clods like clods of earth, we are dealing with a material particularly hard. The drive power of the rotating shafts must be particularly high to break up the clods and pass them through the interstices between the fingers or blades of two neighboring trees. Such a increasing power is costly in energy.

In addition, when the trees are at rest, i.e. no actuated in rotation, the aforementioned interstices necessarily allow the fraction to filter more fluid of the dried material, which is undesirable.

Finally, we know from document WO-A-97/02222 an installation for drying animal droppings, comprising an enclosure the bottom of which is also mobile and permeable.

This bottom is made up of several elements consisting of profiles articulated, able to tilt simultaneously to allow the flow of a fraction of droppings.

This type of installation is satisfactory in terms of operation. However, the tilting operation requires a significant energy consumption.

The present invention aims to overcome these drawbacks.

More specifically, it aims to provide a drying facility for simple and inexpensive design that effectively drains droppings poultry using a reduced air volume. It aims to achieve this goal by using little energy, while recovering the air used with a high degree of moisture saturation.

Furthermore, it aims to provide an installation with a movable bottom and breathable does not have the disadvantages described above.

According to a first aspect of the invention, it relates to a enclosure according to claim 1.

Thus, "the permeable bottom" has only one type of piece in movement, namely the drawer (s). This greatly simplifies the enclosure structure and reduce the energy consumption devoted to moving the drawer.

• vues de côté, les traverses sont disposées en quinconce, les bords des traverses du plan supérieur chevauchant partiellement les traverses du plan inférieur ;
• les traverses du plan supérieur sont ajourées ;
• l'enceinte comporte deux tiroirs de forme rectangulaire, dont la largeur est égale à la moitié de celle du fond, et ces deux tiroirs sont mobiles en sens opposés ;
• les moyens d'actionnement desdits tiroirs consistent en un premier câble qui relie leurs bords transversaux dirigés d'un même côté, ce câble passant sur une série de poulies dont un au moins est motrice, et un second câble qui relie leurs bords transversaux opposés aux premiers, ce câble passant sur une série de poulies de renvoi, de sorte que par actionnement de la poulie motrice, l'un des tiroirs se déplace dans un sens, tandis que le second se déplace dans le sens opposé ;
• ils comprennent des moyens aptes à toujours mettre les deux brins du premier câble, respectivement attachés au premier et au second tiroirs, sous tension ;
• elle comporte un chariot mobile longitudinalement, apte à recevoir ledit mélange et le distribuer uniformément sur ledit fond ;
• ledit chariot porte une série de doigts dirigés vers le bas, aptes à égaliser la couche de mélange déversée sur ledit fond ;
• ladite série de doigts est escamotable en bout d'enceinte.

Furthermore, according to other advantageous and non-limiting characteristics of this installation:

• seen from the side, the crosspieces are staggered, the edges of the crosspieces of the upper plane partially overlapping the crosspieces of the lower plane;
• the crosspieces of the upper plane are perforated;
• the enclosure comprises two rectangular drawers, the width of which is equal to half that of the bottom, and these two drawers are movable in opposite directions;
• the actuating means of said drawers consist of a first cable which connects their transverse edges directed on the same side, this cable passing over a series of pulleys of which at least one is driving, and a second cable which connects their transverse edges opposite to first, this cable passing over a series of deflection pulleys, so that by actuation of the driving pulley, one of the drawers moves in one direction, while the second moves in the opposite direction;
• they include means capable of always putting the two strands of the first cable, respectively attached to the first and second drawers, under tension;
• it comprises a carriage movable longitudinally, capable of receiving said mixture and distributing it uniformly over said bottom;
• said carriage carries a series of fingers directed downwards, capable of leveling the layer of mixture poured onto said bottom;
• said series of fingers is retractable at the end of the enclosure.

The invention also relates to an installation for drying animal droppings.

• des moyens pour mélanger des déjections fraíches avec des déjections sèches ;
• une enceinte de séchage conforme à l'une ou l'autre des caractéristiques précitées ;
• des moyens d'insufflation d'air dans ladite enceinte, au travers dudit fond.

It is essentially characterized by the fact that it includes:

• means for mixing fresh droppings with dry droppings;
• a drying enclosure conforming to one or other of the above characteristics;
• means for blowing air into said enclosure, through said bottom.

• la figure 1 est une présentation très schématique d'une installation incluant une enceinte conforme à l'invention, destinée à montrer les différents éléments qui la composent, la partie inférieure de la figure s'inscrivant normalement dans la continuité de la partie supérieure ;
• la figure 2 est une vue de côté des moyens qui permettent d'alimenter en déjections l'enceinte selon l'invention, son fond étant coupé par un plan vertical longitudinal ;
• la figure 3 est une vue partielle de dessus de traverses qui composent le fond perméable de l'enceinte ;
• la figure 4 est une vue de dessus simplifiée de l'enceinte, avec ses moyens d'approvisionnement en déjections ;
• la figure 5 est une vue de dessus des moyens d'actionnement des tiroirs mobiles qui équipent l'enceinte ;
• la figure 6 est une vue générale de dessus de ces tiroirs, avec leur câble d'actionnement et leurs poulies de renvoi ;
• la figure 7 est une vue de détail de ces poulies et du câble d'actionnement ;
• la figure 8 est une vue de côté du chariot d'alimentation de l'enceinte en déjections, équipé d'une série de doigts égaliseurs ;
• la figure 9 est une vue de détail d'un de ces doigts, en position escamotée.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows of a preferred but non-limiting embodiment. This description will be made with reference to the accompanying drawings in which:

• Figure 1 is a very schematic presentation of an installation including an enclosure according to the invention, intended to show the different elements which compose it, the lower part of the figure normally forming part of the continuity of the upper part;
• FIG. 2 is a side view of the means which make it possible to supply the enclosure according to the invention with droppings, its bottom being cut by a longitudinal vertical plane;
• Figure 3 is a partial top view of sleepers that make up the permeable bottom of the enclosure;
• Figure 4 is a simplified top view of the enclosure, with its means for supplying excrement;
• Figure 5 is a top view of the actuating means of the movable drawers which equip the enclosure;
• Figure 6 is a general top view of these drawers, with their actuating cable and their deflection pulleys;
• Figure 7 is a detail view of these pulleys and the actuating cable;
• FIG. 8 is a side view of the carriage for supplying the enclosure with droppings, equipped with a series of equalizing fingers;
• Figure 9 is a detailed view of one of these fingers, in the retracted position.

The installation represented in FIG. 1 essentially comprises a drying enclosure 1, a set of Archimedes screw conveyors 2 and 3, a conveyor for bringing fresh manure B , as well as means for blowing air A in enclosure 1.

As will be seen below, the underside of the enclosure 1 is provided with a pit 8 for receiving dry droppings S , into which plunges the upstream end of the conveyor 2 with Archimedes screw; its downstream end, which extends outside the enclosure 1, overhangs a first section 30 of a second Archimedes screw 3.

This first section has two directions of rotation, a first direction where the screw it contains directs the materials to enclosure 1 and a second direction where the screw directs materials in the opposite direction.

A chute 300 communicates the conveyor 2 with the section 30. The latter is also open near the chute 300, this opening being located directly above a conveyor B with a movable conveyor belt for bringing fresh manure.

Furthermore, the downstream end of the section 30 communicates with the upstream end of a second section 31, also opposite Archimedes. The meaning of rotation of this screw is unique and is able to direct the materials towards its end open downstream, opposite the first section.

Thus, if the Archimedes' screws of the sections 30 and 31 are actuated in the same direction (by motor means not shown), the dry excrements taken from the pit are poured into a pile S.

In the event that the screw of the section 30 is actuated in the opposite direction, the second section is made inoperative and the conveyor B is started. An intimate mixture M of fresh and dry excrement M then takes place in the section 30 which will be directed into the enclosure 1, as will be seen below.

The drying chamber 1 has the shape of a rectangular parallelepiped elongated and open at the top.

It is provided in its upper part, near one of its longitudinal and vertical walls of a conveyor belt 4 whose strands upper and lower extend horizontally, parallel to each other.

This mat has only one direction of rotation; this sense is such that its strand upper moves from left to right, when we consider Figure 1. Its upstream end is located slightly outside of enclosure 1 and is overhung from outside downstream of section 30 with Archimedes screw.

As shown in Figure 4, the conveyor 4 occupies a tiny part of the width of the enclosure.

The enclosure is also provided, in its upper part, with a mobile carriage 5 in the form of a box, guided in longitudinal translation by rollers 55 bearing on guide tracks provided in the walls of the enclosure.

This carriage is provided with a scraper blade 51 which rests on the strand upper of the conveyor 4. It is also equipped with an Archimedes 50 screw, with an axis horizontal and transverse rotation, which is located in a plane below that of the lower strand of the conveyor 4. The bottom of the trough in which it is moves is partly open.

As will be seen below, the faeces received by the conveyor 4 is scraped by the blade 51, poured into the carriage 5 and distributed over the entire width of the enclosure by screw 50.

Electrical or electronic means not shown, by example with photocell, allow to automatically advance the carriage, as soon as the presence of droppings is detected in the Archimedes screw.

The bottom of the enclosure 1 is generally referenced 6 and is part of a rectangle.

It consists of two series of sleepers 60 and 60 ', arranged horizontally and organized in two parallel superimposed planes P ₁ and P ₂ . The arrangement of the crosspieces is such that the bottom 6 presents no solution of continuity in the vertical direction. In other words, this means that seen from above or from below, the bottom gives the impression of being made up of a single continuous plate. The projection of the background on a horizontal plane therefore forms a continuous surface (devoid of openings).

The cross-pieces are generally flat, not very thick, with cross-section rectangular. They are for example made of metal.

As shown more particularly in FIGS. 2 and 3, the sleepers 60 of the upper plane P ₁ are arranged in such a way that their transverse edges 601 partially overhang the sleepers 60 'of the lower plane P ₂ .

The crosspieces 60 of the upper plane P ₁ are provided with oblong openings 600, arranged transversely. The advantage of such a characteristic will be explained later in the description.

In the space which separates the two planes P ₁ and P ₂ of sleepers 60 and 60 ′ is present at least one drawer T movable horizontally. It is a thin plate, rectangular in shape, the width of which corresponds to that of the bottom. This drawer has the function, as will be seen below, of pushing the droppings which have accumulated on the sleepers 60 ′ of the lower plane so as to evacuate them outside the enclosure.

It is able to sweep the entire surface of the bottom, from one end to the other.

In the embodiment of Figure 6 which corresponds to a particularly advantageous solution, the enclosure is equipped with two drawers T ₁ and T ₂ , in the form of rectangular plates, the width of which corresponds substantially to half that of the pregnant.

These drawers are equipped with means allowing them to be moved in longitudinal translation between the two planes of sleepers, one moving in a sense, while the other moves in the opposite direction.

To do this, each drawer is attached by one of its faces transverse to the end of a first cable 92 which cooperates with a series of return pulleys which have the general reference 9.

More specifically, with reference to Figure 5, is arranged in the axis longitudinal median of the enclosure, a master pulley 90 whose axis of rotation, arranged vertically, is driven by means of a motor not shown. It's about a grooved pulley, advantageously trapezoidal profile. This pulley is associated with two secondary pulleys 90A and 90B so that the path of the cable 92 on these three pulleys gives it substantially the shape of the Greek letter omega (Ω).

The system is also equipped with a second pair of deflection or angle pulleys 91, each being arranged substantially along the longitudinal median axis of the drawers T ₁ and T ₂ .

The transverse faces of the drawers, opposite to the preceding ones, are, in turn, connected by a second cable 93 which cooperate with a pair of deflection or angle pulleys 94 arranged along the median longitudinal median axis of the drawers T ₁ and T ₂ .

The four angle pulleys 91 and 94 are arranged at the corners of a fictitious rectangle, along the long sides of which the drawers are brought to be displaced.

It is understood that the actuation of the pulley 90 in one direction or the other, will result in the displacement of the drawer T, in one direction and, simultaneously of the drawer T ₂ in the opposite direction.

In order to avoid jolts in the operation, due to the fact that the cable strand 92 which corresponds to the non-drawn drawer is soft or loose, as illustrated in FIG. 7, that the two pulleys 90A and 90B are integral with a stirrup, itself secured to the master pulley 90.

Thus, depending on the force exerted on the cable, all of the pulleys 90, 90A and 90B are oriented in the direction of the so-called slack cable, for the powering.

This system eliminates the need for continuous monitoring of the proper functioning of the system.

Of course, when the drawers T ₁ and T ₂ have each arrived at one end of the enclosure 1, the drive motor of the pulley 90 is then piloted so that its direction of rotation is reversed. Limit switches can be used to do this.

Of course, the cable material should be chosen sufficiently resistant. It may for example be steel cables coated with plastic.

Referring to Figure 8, there is illustrated the feed cart droppings with, at its front; a vertical tilting arm 54, the end of which lower is provided with a series of bent fingers 52 directed towards the bottom and in bias, towards the droppings.

The function of these fingers is to evenly distribute the droppings on the sleepers to prevent them from accumulating on the sleepers upper plane, to the detriment of the lower plane.

As shown in Figure 9, this finger system is provided tilting, relative to a connecting piece 53 so that, at the end enclosure 10, it retracts. This allows the carriage 5 to move up to bottom of the enclosure, without being bothered by the fingers.

Below the bottom 6 is provided a scraper system 7 of the type known, which, as will be seen later, is intended to bring back to the pit 8 the dry droppings that have passed through the permeable bottom 6. In a form of particular embodiment, several scrapers can be provided.

Finally, the installation is provided with air supply means A originating for example from a livestock building located near the installation.

This air is brought in from below the bottom and forced to pass through it from bottom to top, for example by means of fans V.

We will now describe how we use the installation and the enclosure of the invention, with reference to the accompanying drawings.

In a preliminary step, a mixture of fresh excrement, for example droppings, is produced with dry droppings so as to produce a loose mixture M , permeable to air. The purpose of this phase is to obtain a product that is easy to handle, unlike a mass of fresh droppings which constitutes a semi-liquid product, much more difficult to handle and treat.

To do this, the fresh droppings are conveyed by the conveyor to conveyor belt B in the aforementioned conveyor section 30.

An intimate mixture of these two products is made inside the screw of the conveyor and the assembly is poured onto the conveyor belt 4 provided in upper part of enclosure 1.

The movement of the carriage 5 relative to the belt 4 causes the mixture to spill and transfer thereof inside the enclosure on the bottom 6. As an indication, the mixture M comprises for example around 50% by weight dry matter.

Care will have been taken, before the spill, to start the air blowing means A , so that it rises inside the enclosure 1 by passing primarily through the intervals between the sleepers 60 and 60 '. A fraction of the air also flows through the openings 600 of the sleepers 60.

As it progresses from the bottom to the top of the enclosure, the air becomes charged with humidity (up to approximately 95%) and gradually dries the mixture M of droppings.

It is of course the mixture layer closest to the bottom 6 which is dried first.

Periodically, the motor of the pulley 90 is actuated in such a way that the drawers T ₁ and T ₂ undergo a translation in opposite direction between the two planes of sleepers 60 and 60 '.

During this maneuver, the fraction of dry droppings that accumulated on top of sleepers 60 'is pushed and falls by gravity to the ground present in the lower part of the enclosure.

The purpose of the presence of oblong holes 600 in the crosspieces of the upper plane P ₁ is to accelerate the drying up of the fraction of droppings which has accumulated therein, because in this zone the droppings are not primarily crossed by the flow air A.

Each transfer of a fraction of droppings through the permeable bottom 6 results in the creation of material cones above the crosspieces 6 of the plane superior. It is to avoid this phenomenon that provision has been made for equalizing fingers 52 on the carriage 5. In this way we constantly equalize the layer of droppings on the background 6.

The scraper 7 is periodically actuated by a system of cable, so as to transfer the dry droppings into the receiving tank 8. At this level, they are collected by the Archimedes 2 screw conveyor and transferred, either fully in an S heap for later use, or mixed partly with a new arrival of fresh droppings.

Obviously this whole process is carried out continuously, fractions of dry droppings being extracted from the enclosure regularly. Means allowing an automatic measurement of the droppings hygrometry can be set up, slightly above the movable bottom.

In an embodiment not shown, the drawers are formed of a frame consisting of an assembly by welding of four sections, namely two longitudinal profiles and two transverse profiles, the interior space they delimit being empty.

In this case, these are the vertical faces of the two profiles which push the droppings that have accumulated on the sleepers lower 60 'from the bottom 6. Preferably, the spacing between the two profiles transverse will be chosen greater than the spacing between two neighboring sleepers. Through example, it can be 75 cm, the spacing between two crosspieces being 50 cm. Of this way, when one of the profiles pushes droppings, the other is inactive, and Conversely. This allows to delimit the power necessary to move the drawers.

In the event that the width of the drawers is two meters, each section moves, each time it "sweeps" a cross member, an area of approximately 1 m ² of droppings (0.5 mx 2 m).

The spacing between the two transverse planes and for example of around 25 mm.

Therefore, the amount of dry droppings removed at each passage of drawers is unimportant.

The technique according to the invention therefore makes it possible to recover regularly, using simple means and consuming little energy, a regular, unimportant and uniform layer of dry droppings, i.e. within which the humidity is everywhere the same.

Furthermore, to carry out this work, it is necessary to develop a tensile force on the cable 92 of the order of 400 kg, which corresponds to a power of the order of 750 watts.

In the hypothesis of a background surface of the order of 200 m ² , if it were necessary to move 200 drawers capable of each sweeping an area of one m ² , the corresponding power to be developed would be 150 kwatts (0.750x200 ).

Finally although the present invention has been described with reference to poultry droppings, other types of droppings can also be treated.

Claims (10)

1. Enclosure for drying animal faeces which is adapted to receive a mixture (M) of fresh faeces and dry faeces, the base (6) thereof being provided to retain the mixture (M) whilst being permeable to air (A), the base (6) consisting of a set of elements (60, 60') which are each able to form means for retaining faeces and having means (T; T1, T2) which permit a portion of the dry faeces to be periodically transferred out of the enclosure (1) and through this base (6), characterised in that said elements consist of two series of horizontal cross-pieces (60, 60') arranged in two superimposed parallel planes (P1, P2), these cross-pieces (60, 60') being disposed such that the base (6) does not have a gap in the vertical direction, and in that said transfer means (T; T1, T2) consist of at least one slide tray which can move in the horizontal direction between these two planes (P1, P2) of the cross-pieces (T; T1, T2), said or each slide tray being formed of a rectangular plate, the longitudinal movement of this slide tray being able to sweep all of the surface of the said base from one end to the other so as to be able to push the faeces accumulated on the top of the cross-pieces (60') of the lower plane (P2) such that the faeces can fall out of the enclosure by the effect of gravity.
2. Enclosure as claimed in Claim 1, characterised in that, seen from the side, the cross-pieces (60, 60') are disposed in a staggered manner, the edges (601) of the cross-pieces (60) of the upper plane (P1) partially overlapping the cross-pieces (60') of the lower plane (P2).
3. Enclosure as claimed in any one of Claims 1 or 2, characterised in that the cross-pieces (60) of the upper plane (P1) are provided with openings.
4. Enclosure as claimed in any one of Claims 1 to 3, characterised in that it has two slide trays (T1, T2), the width of the slide trays being half the width of the base (6), and in that the two slide trays (T1, T2) can move in opposite directions.
5. Enclosure as claimed in Claim 4, characterised in that the actuating means of the said slide trays (T1, T2) consist of a first cable (92) which connects their transverse edges directed from a single side, this cable passing over a series of pulleys (90), at least one (90) of which is a driving pulley, and of a second cable (93) which connects their transverse edges opposite to the first, this cable passing over a series of return pulleys (94) such that upon actuation of the driving pulley (90) one (T1) of the slide trays moves in one direction whilst the second (T2) moves in the opposite direction.
6. Enclosure as claimed in Claim 5, characterised in that the actuating means comprise means which can always tension the two strands of the cable (92), respectively attached to the first (T1) and second (T2) slide tray.
7. Enclosure as claimed in any one of Claims 1 to 6, characterised in that it comprises a carriage (5) which can move in the longitudinal direction and can receive said mixture (M) and distribute it uniformly on said base (6).
8. Enclosure as claimed in Claim 7, characterised in that said carriage (5) has a series of fingers (52) directed downwards which can even out the layer of mixture (M) tipped onto said base (6).
9. Enclosure as claimed in Claim 8, characterised in that said series of fingers (52) is provided in a tiltable manner such that it is able to be retracted at the edge of the enclosure (1).
10. Installation for drying animal faeces, in particular poultry droppings, characterised in that it comprises

    means (30) for mixing fresh faeces with dry faeces;

    a drying enclosure (1) as claimed in any one of Claims 1 to 9;

    means (V) for injecting air (A) into said enclosure (1) through said base (6).

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