EP1409158B1 - Screening method for size sorting of feathers, down, wood needles, or the like maintained in suspension in a fluid - Google Patents

Abstract

The invention concerns a screening method and machine for size sorting in a fluid (9), into two categories, of materials with different volumes and density close to that of the fluid used after total immersion in said fluid. Mechanical stirring (6) means upstream of the sieves, optionally combined with the use of surfactants in an aqueous medium, maintain said materials to be size-sorted suspended in said fluid. The fluid circulates from upstream to downstream of the sieves. Only the materials below a certain size, volume or weight, maintained suspended in the fluid, pass through the size-sorting sieves (15). The sieves are immersed in the fluid and do not slow down the liquid flow passing through them. To obtain further size-sorted categories, it is possible to organise the inventive process sequentially. The invention is useful in poultry processing plants, processing feathers and down for padding purposes, purifying foreign matter in pasty mixtures and the like.

Description

The invention provides a solution for calibrating in two categories, in a fluid, materials with varying volumes and densities close to the fluid used after total immersion in this fluid.

Historical:

Centrifugal separation of materials immersed in a fluid is common. These materials must be of substantially different density from that of the fluid, on the one hand. On the other hand, in the case of a random mixture of materials with different volumes and shapes, their separation into two groups becomes difficult by simple centrifugation: a self-sieving effect is created by amalgamation of the materials of the two groups between they, because of their more or less bulky or hanging forms.

The use of fluid, to separate materials with a density close to the fluid after total immersion, is simply discarded. Thus, for example, for the calibration of feather feathers for bedding, the method used is the calibration by air suction columns (machines called sorters), dry feathers. The principle is to brew the feathers of various sizes at the base of an air intake column. The lower the suction, the more the materials sucked into the ascending column will be fine and light. However, knowing that at the exit of the abattoir the feathers are either wet or wet, the drying of the material becomes imperative before the dry calibration by the air columns. In addition, a prewash may be necessary in corollary drying when animal fat or fouling alter the material to be calibrated. Too much fat makes it difficult to dry, and this dries more fat in the pen. Excessive fouling of the pen alters its actual weight, and thus disturbs the calibration by the suction method in columns. Finally, a fouled feather can also be smelly, and in turn foul the machines used for the treatments before washing.

The invention is at this level of its interest: knowing that on a bird, such as duck for example, 35 to 45% of the weight of the feathers are put in non-recoverable waste for bedding at the end of the complete process of feather treatment (washing, parboiling, dusting, storage, transport, etc.), it is best to separate before any treatment of feathers those that are intended for the bedding of those that will be sent to the squarers. The prototype according to the present invention, used on feathers, gives a striking result. The invention allows several calibration results by sieve modification. It is possible, in the example of the feathers, to separate the feathers of sizes greater than about 5 centimeters, others of different sizes and shapes but smaller. These smaller sizes constitute the noble value of the original material, with the highest value on the feather market. It follows that it is preferable to calibrate in a fluid and to preserve for the total treatment only the most noble elements of the matter of origin. Moreover, if this calibration in a fluid is carried out from the slaughterhouse, with the same water as the one already used for moving the feathers in the slaughterhouse, only the selected feathers will have to be transported to the feather treatment plant, and the larger ones will be transported directly to the chisels. Many other benefits are measurable by the professionals themselves.

The invention provides a method, and a preferred machine, for calibrating with a fluid materials between them, more or less voluminous, and whose densities after total immersion are close to the fluid, or lower.

This is the case for example wood needles, a few centimeters, for example, or various feathers of volatile for the lining of the bedding in particular. These subject enumerations are not exhaustive.

The principle of the invention is to maintain suspended in the fluid, materials to be calibrated during the calibration process. Indeed, the holding in suspension allows to separate one by one the elements that constitute the initial material to be calibrated.

A permanent fluid stream passes through a sieve, this fluid drives with it the finer elements in proportion to the sieve openings.

The staggered stirring of the fluid mixture and materials to be calibrated prevents these materials from being amalgamated with one another by caking or amalgamating at the inlet of the sieve orifices during the displacement of the upstream fluid downstream. sieves.

This mixing can be achieved by a tree and blades, creating a slight centrifugal effect in a vertical cylinder or not. This centrifugation effect is interesting in the case where the materials to be calibrated are of different relative densities and of which those intended to pass through the sieves are denser than the others, thus facilitating sieving by bringing these materials closer to the sieves located on the periphery of the sieve. the walls of the brewing chamber.

This mixing may be the occasion of a chemical treatment in an aqueous medium of the materials to be calibrated, by addition of surfactants or other, and this during the calibration process, in a closed circuit as to the fluid used. The use of surfactants can improve the wettability of materials, color, disinfect, or other effects. A surfactant, or additive, can also be used to modify in aqueous medium the relative densities of the fluid and the materials to be calibrated, in order to improve the propensity of the substances to remain in suspension in the fluid after immersion in this fluid. .

It is necessary to maintain in suspension in the fluid the materials to be calibrated, this throughout the calibration process. To do this, the sieve must not create a bottleneck effect during the flow of both the fluid and any calibrated material due to their passage through the sieve. The screen is immersed between two fluid zones of substantially identical pressures, the pressure upstream of the screen being slightly higher than that downstream in order to create the effect of flow from one zone to another. For exemple ( figures 1 and 2 ), two enclosures, one in the other, with sieves (3,4 and 5) fixed on the walls of the smaller of the two (1), and a fluid which enters (9) first in this small chamber to flow through the sieve, and penetrate the larger enclosure (2) which is waterproof. This larger enclosure has a discharge orifice (7) equivalent flow rate to that entering (9) in the small enclosure, the fluid level remains stable and substantially equal between these two communicating speakers. During the displacement of the fluid, the materials to be calibrated go, or do not go, one by one, follow the path of the fluid through the screens according to the characteristics of the latter. At this stage, the calibration is all the more perfect as the circulation of the fluid is slow at the sieves.

A second method of application of the invention is to divide the same enclosure ( figure 5 ), using sieves, in two superimposed zones (1 and 2), with fluid flow, by gravity, from an upper zone (1) to the other lower zone (2), via sieves (3) ). Fluid evacuation (7) from the downstream zone of the screen creates the flow, but this flow is regulated according to the size of the sieves and the materials to be calibrated in order to avoid bottlenecks at the sieve entries. A compromise is to be found to obtain a speed of calibration, or productivity. This compromise depends, among other things, on the number of orifices constituting the sieve and on the fineness of the desired sizing.

The characteristics of the sieve will depend on the materials to be calibrated. The sieve consists of two main parts. One is composed of multiple tubes (15), juxtaposed in linear series. These linear series of tubes are positioned on the walls of the stirring chamber (1) perpendicular to the direction of the stirring made in this chamber ( figure 4 ). The other is an output stop (23) for each series of tubes. Thus, the tubes (15) juxtaposed in rows, or checkerboard, form the orifices (22 and 23) of the sieves and have a shape and a size adapted to the materials to be calibrated during their eventual passage through the sieves. These tubes (15) are of identical shape, more or less elongated (A) and diameter (C) more or less important. Each tube will preferably be unstretched to eliminate any risk of blockage of materials having curved shapes and bad luck positioned in the opposite direction of the curved shape of the tube. The sieve abutment (17) forms a bend (18) approaching 90 degrees, open on one side (20) to allow flow of fluid and material passing through the sieve. This stop will have its opening (20) rotated in the direction of mixing the fluid in the sieving chamber. This stop will be positioned at the outlet (23) of the sieve tubes, but at a distance (B) sufficient to allow the flow of the fluid and materials thus selected. The cumulative length of the tubes and the space between the ends of the tubes and the abutment (A + B) is such that the elements that are too long can not pass beyond this sieve. Thus, a material ( figure 4 ) such as a feather (19) for example, engaged in a tube (15), coming into contact with the stop (17), and of a length such that it does not sufficiently exceed the inlet orifice (22) of the tube, then a compromise between the sizes A, B, C and D of the sieve must allow this material to continue its way downstream of the sieve, aided by friction, in the sieve parts, the fluid alone or the fluid loaded with materials. The goal is to not obstruct the screen openings so as not to create a bottleneck effect for the flow of fluid and any materials.

A closed circuit for the fluid saves the amount of fluid to be used during the calibration process. To do this, the selected elements, after passing through the sieve, then the passage in the chamber (2) serving as envelope to the first ( figure 1 ), and finally the passage beyond the valve (7) for emptying the same second chamber, are separated from the fluid by a separator device. Beyond this separator, the purified fluid of the selected materials goes back by a device, pumping for example, upstream of the calibration process located at the enclosure with sieves.
As for the selected materials, they are grouped together and sent to a storage or treatment area other outside the invention.

• La figure 1 présente, en perspective latérale, un exemple de deux enceintes l'une dans l'autre, dont l'une munie d'un dispositif de brassage avec pales, et le circuit fermé de fluide.
• La figure 2 est une vue de dessus de la cuve munie de tamis, et d'un arbre central avec pales pour le brassage des matières immergées.
• La figures 3 propose un vue de face de plusieurs modes possibles de tamis, avec orifices rectangulaires, et la butée présentant un coude proche de 90 degrés.
• La figure 4 présente à nouveau le même mode de tamis présenté sur la figure 3, mais avec une perspective latérale surélevée. Le tamis est présenté solidaire de la paroi (21) du cylindre. Enfin, a titre d'exemple, une plume est positionnée dans un des orifices du tamis, mais arrêtée par la plaque de butée en raison de sa longueur et rigidité.
• La figure 5 présente en complément de la figure 1 une autre configuration possible des enceintes. Elles sont ici superposées, et séparées par les tamis. Les numéros sont les mêmes que sur la figure 1 pour des fonctions équivalentes.

Finally, materials that have failed during the sieve calibration process remain trapped in the sieved enclosure. At the end of the time given to the calibration, it is necessary to extract these materials prisoners from this chamber by a device adapted to the configuration of these speakers (11 on figures 1 and 4 ), before proceeding to a new calibration cycle with a new raw material. This extraction of the fluid loaded with the trapped materials, is also the subject of a separation of the fluid on the one hand, and materials on the other hand, by a separator. The fluid starts upstream of the calibration process located at the chamber equipped with sieves. As for the materials, they are discarded, at this final stage of calibration, the machine of the invention.

• The figure 1 presents, in lateral perspective, an example of two enclosures in one another, one provided with a stirring device with blades, and the closed circuit of fluid.
• The figure 2 is a top view of the tank with sieves, and a central shaft with blades for mixing submerged materials.
• The figures 3 proposes a front view of several possible modes of sieves, with rectangular openings, and the abutment having an elbow close to 90 degrees.
• The figure 4 presents again the same sieve mode presented on the figure 3 , but with a raised side perspective. The screen is shown integral with the wall (21) of the cylinder. Finally, for example, a feather is positioned in one of the sieve orifices, but stopped by the stop plate due to its length and rigidity.
• The figure 5 present in addition to the figure 1 another possible configuration of the speakers. Here they are superimposed and separated by sieves. The numbers are the same as on the figure 1 for equivalent functions.

A preferred method of application of the invention:

The principle is based on the flow of a fluid from an initial zone, to a secondary zone, via a sieve, with the help of a continuous supply of fluid upstream of the system, proportional to the flow of fluid leaving the zone. secondary by a drain valve: effect of communicating vessels. This fluid will cause some of the elements contained in the initial zone towards the emptying of the secondary zone.

The prototype developed proposes a preferred embodiment of the invention applied to the raw duck feather, wet.

Use a vertical cylindrical tank (1), such as a standard 200-liter drum, positioned in a tank (2) of any shape but of sufficient height to allow the immersion of about three-quarters of the cylinder height ( 1).

This cylinder (1) is provided with sieves (3,4 and 5) distributed on its periphery, in vertical rows of orifices in sufficient number to allow a fluid flow sufficient for the productivity of the calibration. These columns of orifices are as high as the cylinder itself, with the exception of a shift at the base of the cylinder in the case of heavy particles such as metal parts, pebbles, volatile offal in the case of calibration of feathers coming from directly from slaughterhouse, or others, which can be deposited at the base of the cylinder. Thus, these heavy and undesirable particles, sometimes small volumes, do not cross the sieve, do not deteriorate and do not obstruct it. This cylinder is traversed by a motorized rotary axis and provided with blades (6). These blades graze the sieves.

The sieves are a series of small tubes (15) square or not, about 2 to 5 centimeters (C) side or diameter, and about 3 to 5 centimeters (A). A plate (17) serving as a stop is fixed on the side of the outlet (23) of the tubes so that the elements that are too long or too rigid, which will engage in the small tubes, abut on this plate, and turn back in the cylindrical tank thanks to the action of the stirring in this cylinder. The materials or the bubbling fluid will release these elements momentarily stationed in the small tubes of the sieve, releasing the orifices (22) again to continue the calibration. This abutment plate (17), bent (18) is spaced from the outer end (23) of the tubes approximately 2 to 3 centimeters (16), and open (20) from the side opposite to the direction of the stirring of the fluid in the cylinder.
Thus, an element (feather for example, Figure 4 ) of length much greater than A + B, coming into abutment on the abutment plate (17), tends to be positioned at an angle in the direction of stirring (19). It is therefore appropriate that the base of this feather element remains in abutment until its release by stirring, without the risk of being driven by the constant stream of fluid converging towards the outside of the cylinder through the screen. On the other hand, an element (pen for example) of length barely greater than A + B, and still less than this length, coming into abutment on the plate (17), is unlikely to turn back towards the enclosure upstream of the sieves because of its low gripping surface upstream of the tube, reducing its propensity to be captured by the friction of the materials and the fluid upstream of the sieves. At this stage, this material must leave the sieve downstream, thanks to a sieve having an opening (20) large enough that the element in this example can be skewed in the sieve and, despite its rigidity and length, cross the elbow of the stop.

An enclosure serving as envelope (2) receives the charged fluid of the selected materials (8) at the exit of the screens. This enclosure of any shape but tight surrounds the cylinder (I) because in our embodiment of the invention, the screens are distributed over its entire periphery. This enclosure, enveloping the cylinder, has a level of fluid necessarily close to that of the cylinder.

The circulation of the fluid is ensured by a supply (9) of the cylinder (1), and a discharge valve (7) variable flow at the outlet of the enclosure envelope (2). Thus, the flow rate of the fluid will be almost identical at all stages of the calibration process, including the following three places: feeding from the top of the initial cylinder, passing through the orifices of the sieve, and finally the emptying of the enclosure-casing.

For the pen for example, a prototype of reduced size has been designed, and whose characteristics are not limited to the design possibilities of calibration machines according to the invention. The steps in the process are:
Fill with fluid, not loaded with materials, three-quarters of the volume of the two tanks, communicating tanks via sieves. This level is considered reasonable for proper operation of the system without overflow. The drain valve of the shell-tank remains closed during the filling of the tanks.

Then introduce the raw material to be calibrated in the cylinder (1) provided with an axis and 5 rotating blades, about 90 revolutions per minute. If the pen is dry, then thanks to the mixing in this cylinder, it will eventually be completely immersed, a necessary condition for calibration with fluid. At this stage of the process, it is possible to add a chemical for any treatment of the material, but without this product is foaming.

A non-foaming degreaser, for example, will prewash the pen during the calibration process. A surfactant added to the fluid, for example water, can also improve the wettability of the pen. The amount of raw feathers to be introduced into the cylinder (1), equivalent in dry weight, is about 3 to 7 kilograms for the cylinder of the prototype having 50 centimeters in diameter and 80 centimeters in height. The more the initial material consists mainly of elements not crossing the sieve, the lower the amount of material to be introduced at the beginning of the calibration cycle. Indeed, the calibration will be less effective if during the entire duration of the calibration the stirring cylinder is saturated with elements intended to remain prisoners of the cylinder. The stirring of course improves the calibration by unclogging the sieve at regular intervals.

The calibration process can then start by simultaneously opening, at equivalent flow rates, the supply valve (9) with fluid from the top of the cylinder, and the drain valve (7) located at the outlet of the tank-casing. (2). Calibration time, for 4 kilograms, is 3 minutes with the prototype. This productivity can be multiplied by a sizing of the sieves, the size of the tanks and cylinders, the flow of fluid, etc.

To save the amount of fluid to be used during the calibration process of the feathers or other similar materials, the invention provides for recovering in a closed circuit (14) this fluid beyond the drain valve (7) after having purified the fluid of its feathers suspended by a separating device (10). The feathers selected, because they have crossed the sieve, are removed from the system by means such as conveyor for example.

At the end of the time allotted to the calibration, ie 3 minutes in our example, it is necessary to eject by any device the feathers remaining trapped in the mixing cylinder (1), but without any communication. with the tank (2) in which may reside some selected materials remained suspended in water. The circulation of the fluid is maintained but its circuit is momentarily modified: At this end of calibration stage, the emptying valve (7) of the tank (2) closes, and simultaneously the valve (11) situated at the base of the cylinder (1) opens to release the fluid loaded with the feathers trapped in the cylinder to a duct (12) passing through the tank (2), and opening on a separating device (13) to purify the fluid of its large feathers. The water is reused in closed circuit (21) in the system of the invention. At this stage of removal of the materials trapped in the cylinder, the water inlet above the cylinder must be sufficient for two reasons: On the one hand, moving the large feathers to the pipe (12), the effect of caking being reduced because of the stirring retained in the cylinder, and secondly, to avoid a reversal of the direction of flow from the tank (2) to the cylinder (1) by the effect of communicating vessels, this in the case where the level fluid flow in the cylinder would descend due to evacuation flow greater than that of the upstream supply, and thus back through the sieve feathers previously selected but remained suspended in the tank-envelope (2). This inversion of the flow direction of the fluid will partially lose the benefit of the calibration system, object of the invention. The time to drain the feathers trapped in the cylinder can last a few seconds with an efficient flow of fluid and materials. In sequence, the valve (11) of the cylinder closes, and that (7) of the tank-envelope, opens again, to find the initial circuit of the flow for calibration from the mixing cylinder to the tank -wrap, through the sieves. The loading of materials to be calibrated is then again possible, and the process follows the previously described steps.

The cycle thus presented of the calibration process can be modified according to the composition of the materials to be calibrated. Thus, a material composed mainly of elements passing through the sieve, avoids the discharge of trapped material upstream of the sieves at the end of each sizing process, the latter remaining in small quantities upstream sieves. The calibration process then becomes as follows: Regular and continuous feeding of material upstream of the sieves into the stirring cylinder, then stopping the feed, and allowing the calibration process to continue as described by the invention over a period deemed sufficient, and then proceed to the actual emptying of the trapped materials upstream of the sieve in accordance with the process described by the invention. This process significantly increases the productivity of the calibration in the case of materials mainly composed of elements crossing the sieve.

The productivity per hour can reach several hundred kilograms of raw feathers entered in the machine, in dry equivalent weight, depending on the dimensions of the machine. The invention allows a total and easy adaptation of the size of the system, by juxtaposable modules. Thus, a tank-envelope can contain several cylinders equipped with stirring and sieves. A brewing cylinder can also have a large size.

On the other hand, in this example, the invention eliminates most of the non-usable feathers for bedding, up to 40% of the weight of feathers entered the machine. The machine allows to calibrate the feathers according to the desired lengths. The treatment of feathers for the bedding is then limited only to the materials calibrated by the invention.

In addition, wet feathers from slaughterhouses are most often loaded with waste of all kinds, such as legs or heads of slaughtered animals, offal or even whole animals fallen from the slaughter line. These intrusive materials make it difficult to wash the feathers in a single operation because of the odors caused during the steaming after washing. The invention provides a happy answer by allowing prisoners to retain intruder elements within the sieving chamber because of sieves and the lower part of this chamber which serves as retention for these heavy materials.

The tests with the prototype made it possible to separate the feathers of sizes smaller than 4 cm, from those larger than this size, for a type of sieve having, on the one hand, smaller orifice tubes, and on the other hand on the other hand, a smaller distance between the end of these tubes and the stop, all things being equal. This allows the use of the invention in successive steps in successive calibration sieves adapted, in order to calibrate in 3 or 4 different sizes raw materials in the same flow. The first enclosure keeps the larger elements in captivity, the others flow to a second enclosure, which in turn keeps the intermediate-sized elements captive, etc.

Claims (10)

1. A method for calibrating feathers, downs, wood needles, or the like, characterized in that the materials are calibrated by sieving, after total immersion of the materials and of the sieves in a fluid, and maintaining materials in suspension in this fluid by mixing or stirring at least upstream from the sieve.
2. The method according to claim 1, characterized in that the displacement of the materials through the sieve is ensured by the flow of the fluid and by permanently maintaining the materials in suspension in the fluid.
3. The method according to claims 1 and 2, characterized in that a surfactant is used in the closed circuit of the fluid, during the process of mixing and calibrating the materials, the use of surfactants improving wettability of the materials, coloring them, disinfecting them, or producing other effects, a surfactant or additive being also used for modifying the density of the fluid or of the materials to be calibrated in order to improve the propensity of the materials of remaining in suspension in the fluid after their immersion in this fluid.
4. The method according to one of the preceding claims, characterized in that circular mixing in a round enclosure creates a centrifugal effect useful for separating materials of different relative densities and including those intended to cross the sieves which are denser than the other materials and denser than the fluid, an effect of bringing closer together the most dense materials towards the sieves located at the periphery on the walls of the sieving enclosure.
5. A machine for applying the method according to any of the preceding claims, characterized in that it includes a sealed enclosure (2), fed with fluid from a sieving enclosure (1), and a discharge outlet (7), the passing of the fluid from one enclosure to the other being achieved via the assembly of the sieves (3, 4 and 5), the sieving enclosure including sieves identical with each other distributed on its walls, only the lower portion of the sieving enclosure not including any sieves so that the undesirable and heavy elements (stones, metal pieces, etc...) erroneously mixed with materials to be calibrated deposit therein by gravity, and avoid blocking the orifices of the sieves, this enclosure being in turn fed (9) with fluid from a reservoir of fluid upstream from the machine.
6. The machine according to claim 5, characterized in that the sieving enclosure (1) contains mechanical means, such as moving blades, skimming the sieves in order to both generate a mixing or turbulent effect, limiting the plugging of the sieves by the materials, and contributing to maintaining the materials in suspension in the fluid.
7. The machine according to claims 5 and 6, characterized in that the fluid circulates in a closed circuit, penetrates (9) the calibration machine through the sieving enclosure (1), crosses the sieves (3, 4 and 5), flows into the second enclosure (2) with suspended materials (8) thereby calibrated by their crossing of the sieves, the mixture of fluid and calibrated suspended materials (8) leaves this second enclosure through the discharge outlet (7), and then enters a separator (10) for stripping the fluid of its suspended materials, and this fluid is then transferred (14) to the starting point of the process (9), before reaching the separator (10), the mixture of fluid and suspended materials calibrated by the sieve used penetrates a new mixing enclosure with a sieve having characteristics different from the first, and obtains an intermediate category of calibrated materials, in the case of a succession of two or more sieving enclosures, each sieving enclosure provided with its own sieves with different characteristics, confining a subcategory of materials.
8. The machine according to claims 5 to 7, characterized in that the materials remaining confined in the calibration enclosure (1), i.e. remaining upstream from the sieves because of their shapes or sizes incompatible with the characteristics of the sieves, are discharged to the outside of the process at the end of the calibration cycle through an aperture (11), the discharge outlet (7) closing during the discharge of the confined materials upstream from the sieves, the supply of the fluid (9) allowing the confined materials of the calibration enclosure to be conveyed towards the orifice (11), and to be transferred through a conduit (12) towards a separator (13) for stripping the fluid of its suspended materials, and this stripped fluid being then transferred (21) towards the starting point of the process (9).
9. A sieve for applying the method according to claims 1 to 4, characterized in that it consists of a series of tubes (15) of length A and of diameter C, the outlet orifices (23) of which are provided with an abutment (17), forming a bend (18) open on one side (20), with a length D greater than C, spaced out by a distance B away from the outlet orifice (23), the ratio between the distances A and B having to be evaluated, depending on the characteristics of the materials to be calibrated, and on the diameter of the tubes, a material engaged in a tube either parallel or not to the walls of the tube, and coming into contact with the abutment (17), and with a length such that it does not sufficiently jut out from the inlet orifice (22) of the tube, then a compromise between the sizes A, B, C and D of the sieve allowing this material to continue its path towards the downstream portion of the sieve, assisted by the friction of the fluid alone or of the fluid loaded with materials, in the portions of the sieve.
10. The sieve according to claim 9, characterized in that the tubes (15), which make it up, are juxtaposed in linear series, with one bent abutment per series of tubes, the linear series being positioned perpendicularly to the direction of motion of the mixture of fluid and materials in the sieving enclosure, and the bend (18) of the abutment (17) being positioned in the direction of motion of this same mixture of fluid and materials.

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