CN117396642A

CN117396642A - Method and apparatus for washing feathers and removing foreign materials

Info

Publication number: CN117396642A
Application number: CN202280038845.2A
Authority: CN
Inventors: R·菲利雷斯
Original assignee: Tessenderlo Chemie NV SA
Current assignee: Tessenderlo Chemie NV SA
Priority date: 2021-04-29
Filing date: 2022-04-28
Publication date: 2024-01-12
Also published as: EP4330451A1; AR125484A1; BR112023022482A2; WO2022229362A1; EP4083279A1; CL2023003198A1; KR20240004532A; CA3218005A1

Abstract

Washing system (1) suitable for continuous treatment, suitable for pre-treatment of keratin materials, preferably feathers, hair or wool. The washing system (1) comprises a feeding device (2) for feeding the keratin materials to the washing system (1) and a washing space (3) for washing the keratin materials with an aqueous washing liquid. A washing liquid system for supplying the washing liquid to the washing space (3) and extracting the washing liquid from the washing space (3) is included in the washing system (1). The washing space (3) comprises a sinking zone, wherein material having a higher density than the washing liquid sinks under the keratin materials. An extraction system (8) is located at the bottom of the sinking zone (6) for extracting the material having a density higher than the washing liquid. Furthermore, at least one washing structure (4) is present in the muscle ashing space (3), which shakes the washing liquid and/or causes turbulence in the washing liquid. Finally, a discharge device (9) for extracting the keratin materials from the washing system (1) is provided.

Description

Method and apparatus for washing feathers and removing foreign materials

Technical Field

The present disclosure relates generally to washing of keratin materials prior to being subjected to further processing (such as hydrolysis processes) or used in the down industry.

Background

Animal feathers, hair, wool, hooves, nails, etc. are sources of keratin materials. Such keratin materials are typically byproducts of slaughter from poultry, pigs, cattle, sheep, etc., which are high in protein content, but most of the proteins are not digestible themselves, e.g. as low as only 20% of the proteins are digestible. Poultry feathers typically contain about 80% to 90% of the protein in the form of beta-keratin. The relatively high keratin content of cysteines in proteins that cause cross-linking.

However, such keratin materials are hardly digestible by animals or humans due to the high degree of cross-linking with the (di) sulphur bridges. Therefore, keratin must be cleaved and then its protein content can be digested by animals (McCasland and Richardson 1966, poult. Sci.,45:1231-1236; moran et al 1966Poult. Sci., 45:1257-1266).

Thus, hydrolyzed feathers can provide an inexpensive source of digestible proteins and amino acids. Accordingly, the feather hydrolysate (i.e. hydrolyzed feathers) can be used in a variety of ways, such as in animal feed.

Methods for processing feathers or hair to increase digestibility and allow it to be used as a protein source for feeding poultry and livestock are known in the art. Typically, such methods involve using hydrolysis to break disulfide bridges (and at least a portion of peptide bonds) in the keratin protein, and incorporating the resulting hydrolyzed protein into feed. Common methods of processing keratin-containing materials are further classified as 1) hydrothermal and pressure treatment methods, 2) acid, base and/or enzymatic hydrolysis methods, or 3) combinations thereof. Keratin materials are often not fully hydrolyzed to mono-amino acids, as this is not necessary to improve digestibility.

Several methods for producing partially hydrolyzed keratin materials such as feather meal are known in the art; including US5772968, US4286884, US4172073, EP2832236 and EP 2832237 using only steam and pressure. The resulting material from the partial hydrolysis of keratin materials is partially insoluble in water and may comprise a mixture of liquid (dissolved) and solid (insoluble materials). Typically, the resulting product is subsequently dried to obtain a solid product. Drying can significantly affect material digestibility according to, for example, pepsin and/or ileal digestibility tests. Recently, improved keratin material processing and drying methods have been developed which produce hydrolyzed keratin materials with improved digestibility, as described, for example, in EP 3 192 377 A1 and EP 3 402 340 A1.

In the down industry, down and feathers need to be properly cleaned and classified in order to use down, for example, in jackets, pillows, and blankets. In this process, down and feathers are first passed through a dust removal system to remove fine dust and other foreign particles. Next, the down and feathers are washed in a washing system and then dried in a drying system. The sorting system separates the down from the feathers so that the down and feathers can be bagged and further processed. Although down is washed and some foreign material is removed during this process, only fine dust and bacteria are removed and the method is not suitable for removing e.g. larger foreign material.

Document WO2014180681A1 discloses a feather washing machine comprising a washing drum which is rotatably mounted about a horizontal axis and which is divided into successive treatment chambers by means of transferring feathers from one chamber to the other. Each treatment chamber comprises a space for receiving a predetermined volume of feathers to be treated, which feathers undergo four continuously performed treatment operations when the drum rotates about a horizontal axis and by means of four respective treatment zones comprised in the chamber. This document relates only to the treatment of small batches of feathers. No mention is made of specific impurities nor of their effect on the quality of the keratin material.

The inventors found that keratin starting materials typically obtained from slaughterhouses vary greatly in quality and may be of low quality due to the presence of foreign materials and/or the signs of microbial spoilage (indicated by high biogenic amine content). This has a significant negative impact on the process efficiency and/or the quality of the final hydrolyzed keratin material or down used in the down industry.

It is therefore an object of the present invention to provide a solution, such as an apparatus and a method, for managing keratin starting materials of different qualities, resulting in an improved process efficiency and/or quality of the final hydrolyzed keratin material or down used in the down industry. This applies in particular to feather meal obtained after hydrolysis with steam and pressure or after chemical hydrolysis.

Disclosure of Invention

In order to solve the drawbacks of the prior art discussed above, and in particular to reduce the amount of unwanted particles, the present invention provides, according to a first aspect, a washing system suitable for continuous processing, suitable for pre-treating keratin materials, preferably feathers, hair or wool. The washing system includes:

a feeding device for feeding the keratin materials to the washing system;

a washing space for washing the keratin materials with an aqueous washing liquid;

a washing liquid system for supplying the washing liquid to the washing space and extracting the washing liquid from the washing space;

wherein the washing space comprises a sinking zone, wherein material having a higher density than the washing liquid sinks under the keratin materials;

an extraction system at the bottom of the sinking zone for extracting the material having a density higher than the washing liquid;

at least one washing structure which shakes the washing liquid and/or causes turbulence in the washing liquid present in the washing space;

a discharge device for extracting the keratin materials from the washing system.

The washing system provides an efficient way of continuously treating keratin materials. Unwanted material having a density greater than the wash liquor is effectively removed from the keratin material, and the keratin material is subsequently extracted from the washing system.

In one embodiment, the sink zone comprises a flow system adapted to impart a flow to the wash liquor in the sink zone, wherein the flow is sized and oriented such that the keratin material remains in suspension and moves away from the extraction system while the material having a density greater than the wash liquor remains submerged toward the extraction system.

In one embodiment, the washing space further comprises a cleaning zone for cleaning the keratin materials, the sink zone and the cleaning zone being positioned such that the keratin materials first enter the sink zone before entering the cleaning zone, wherein at least one washing structure is located in the cleaning zone.

In one embodiment, the washing liquid system further comprises a washing liquid recycling system for recycling the washing liquid after use in the washing space, wherein the washing liquid recycling system comprises a washing liquid solids separation system, preferably a filter, for cleaning the washing liquid.

In one embodiment, the washing system further comprises an excess washing liquid removal device for extracting excess washing liquid from the keratin material after the keratin material has been washed in the washing space, preferably wherein the excess washing liquid removal device extracts excess washing liquid at the discharge device and/or wherein the extracted excess washing liquid is reused in the washing space.

In one embodiment, the washing structure is cylindrical in shape and comprises one or more protrusions on the cylindrical surface, and wherein the washing structure is rotatably mounted on the washing system, preferably mounted such that the keratin material is at least partially submerged due to the effect of the protrusions when the washing structure is rotated.

In one embodiment, the bottom surface of the submerged region is inclined towards the extraction system, and/or wherein the extraction system comprises a spiral extractor.

According to a second aspect of the present invention, a method for pre-treating keratin materials, preferably feathers, hair or wool, is presented. The method comprises the following steps:

feeding the keratin materials to a washing system, the keratin materials comprising one or more contaminants;

washing the keratin materials in an aqueous washing liquid using the washing system, wherein the one or more contaminants are dissolved into and/or at least partially removed from the keratin materials by the washing liquid;

obtaining pretreated keratin materials from the washing system;

characterized in that the washing is performed such that the amount of at least one of these contaminants contained in the pretreated keratin material is below a predetermined threshold.

In one embodiment, the washing is performed such that the amount of at least one of the contaminants contained in the pretreated keratin material is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material prior to washing, wherein the amount is determined as weight/weight on a dry basis (w/w).

In one embodiment, the one or more contaminants are selected from the group consisting of: biogenic amines, preferably tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and/or agmatine.

In one embodiment, the washing is performed such that the amount of at least one of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine contained in the pre-treated keratin material, preferably the amount of putrescine and/or cadaverine and/or tyramine is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material before washing, wherein the amount is determined as w/w on a dry weight basis.

In one embodiment, the combined amount of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine comprised in the pretreated keratin material, preferably the combined amount of putrescine and/or cadaverine and/or tyramine is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material before washing, wherein the amount is determined as w/w on a dry weight basis.

In one embodiment, the washing of the keratin materials comprises a sinking step, wherein the sinking of the material having a density greater than the washing liquid is lower than the keratin materials and is then extracted at a point lower than the location of the keratin materials.

In one embodiment, the washing of the keratin materials comprises maintaining the amount of at least one biogenic amine dissolved in the washing liquid below a predetermined threshold by extracting the used washing liquid and supplying fresh washing liquid, preferably by continuously discharging the used washing liquid and continuously supplying fresh washing liquid, preferably maintaining the amount of at least one biogenic amine selected from the group consisting of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine dissolved in the washing liquid below a predetermined threshold.

In one embodiment, the wash liquor further comprises a surfactant and/or biocide and/or degreasing agent and/or bleaching agent and/or organic solvent.

In one embodiment, the amount of pretreated keratin material per hour is greater than or equal to 0.5 metric tons/hour, preferably greater than or equal to 1 metric ton/hour, more preferably greater than or equal to 2 metric tons/hour, and wherein the washing is performed in a washing space, wherein the amount of washing liquid present in the washing space is greater than or equal to 1m ³ Preferably greater than or equal to 2m ³ Greater than or equal to 2.5m ³ And wherein the total amount of wash liquor is recycled at least 5 times per hour, preferably at least 10 times per hour, more preferably at least 15 times per hour.

In one embodiment, the washing system is a washing system according to the first aspect of the invention.

According to a third aspect of the present invention, a process for producing hydrolysed keratin materials is disclosed, comprising the steps of:

(i) Washing the keratin materials using a washing system according to the first aspect of the invention or a method according to the second aspect of the invention;

(ii) Hydrolyzing the keratin material;

(iii) Drying the hydrolyzed keratin material, thereby obtaining a dried hydrolyzed keratin material.

According to a fourth aspect of the present invention, a method for processing keratin materials for the down industry is disclosed, comprising the steps of:

(i) Washing down-containing keratin materials using a washing system according to the first aspect of the invention or a method according to the second aspect of the invention;

(ii) Drying the washed keratin materials;

and wherein the down is separated from other keratin materials either before or after the washing step.

According to a fourth aspect of the present invention, a method for washing keratin materials, preferably feathers, hair or wool, wherein the keratin materials are contaminated with materials having a density greater than the keratin materials, is disclosed, comprising:

washing the keratin materials in a washing system using a washing liquid, wherein the keratin materials float and wherein materials having a density greater than the washing liquid sink;

an extraction system is used to extract the material having a density greater than the wash liquor at the bottom of the wash system.

In one embodiment, the method further comprises imparting a flow of wash liquor in the washing system, wherein the flow is sized and oriented such that the keratin materials remain in suspension and move away from the extraction system while material having a density greater than the wash liquor still sinks toward the extraction system.

In one embodiment, the flow is sized and directed so as to have a flow rate of greater than 1.01g/cm ³ Preferably greater than 1.08g/cm ³ Is sinking while most of the keratin materials remain suspended in the washing liquid.

The inventors have found that extraneous, unwanted materials are often present in keratin starting materials. For example, feathers of a poultry carcass are extracted by a robot finger made of rubber. These rubber plucking fingers are often separated from the plucking robot and eventually become foreign material in the feathers. When feathers are used as keratin starting materials, the rubber plucking fingers may clog or even damage processing equipment such as hydrolyzers (particularly continuous hydrolyzers). Other extraneous materials that are often present are pieces of metal that are separated from slaughterhouse processing lines and other body parts that are not needed. This can create problems in the down industry because unwanted other body parts can contaminate a batch of down. Common solutions for removing foreign material, such as metal detectors on processing lines, have several drawbacks. For example, the rubber plucking fingers are not detected and in case metal is detected, this results in a great inefficiency, as either the process line needs to be stopped and the operator needs to search for and remove metal particles, or a part of the feed material is automatically discharged, resulting in a large/disproportionate loss of feed material.

In addition, the inventors have found a high degree of variability in the amount of biogenic amine present in the keratin starting material. These biogenic amines, such as tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine, may be anti-nutritional and/or signs of microbial spoilage. Furthermore, some biogenic amines (especially putrescine and cadaverine) impart strong malodour to keratin starting materials. The inventors have found that it is advantageous to reduce the amount of biogenic amine in the keratin starting material (and thus in the final product, such as hydrolyzed keratin material intended for use in the food or feed sector or in down for the down industry). The inventors have found that conventional processing steps, such as hydrolysis of keratin materials, are insufficient to reduce biogenic amine content, especially where the keratin starting material has a relatively high biogenic amine content.

The present invention provides a method and apparatus for filtering such unwanted foreign material in an efficient manner while concomitantly reducing the amount of biogenic amine in the keratin starting material (and thus, for example, in hydrolyzed keratin material).

Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Fig. 1 to 5 show a schematic overview of a washing device for washing keratin materials from a front view, a rear view, a side view and a perspective view.

Fig. 6 to 7 schematically show the washing space and the feeding and discharging of the washing space 3.

Fig. 8A, 8B, 9 and 10 show detailed schematic views of the sinker 6.

Figure 11 shows a detailed schematic side view of the sinker 6.

Fig. 12 shows an exemplary appearance of the sink zone.

Fig. 13 shows a flow chart describing various steps in the (pre) processing of keratin materials.

The drawings are for illustrative purposes only and are not intended to limit the scope or protection defined by the claims.

Detailed Description

Hereinafter, certain embodiments will be described in more detail. However, it should be understood that these embodiments should not be construed as limiting the scope of the present disclosure.

Fig. 1 to 5 show a schematic overview of a washing device 1 for washing keratin materials from different sides.

The keratin materials may be, for example, feathers, hair, wool, hooves and/or nails. According to the invention, the keratin materials are washed before subjecting them to a smelting treatment, preferably before hydrolysing them.

The keratin material is preferably feathers, hair and/or wool. The inventors have found that separation between foreign materials (e.g., plucking fingers, metal parts, sand, etc.) is more effective for these materials. Most preferably the keratin material is feathers (large feathers, down feathers and mixtures thereof). The feather can be from chicken, duck, goose, turkey, etc. Preferably, the chicken feathers are washed in the method or apparatus of the invention, as chicken feathers are a very common waste stream.

The keratin materials may be fed into the washing apparatus 1 using a feeding device (not shown). The feed device may comprise a screw conveyor, a conveyor belt, a pump, a trommel screen and/or a rotary screen. The conveyor belt may include a screen or perforations. The feeding device feeds keratin materials to the washing apparatus 1 at a feed position 2. The feed location 2 may comprise, for example, a feed hopper.

The washing apparatus 1 contains an aqueous washing liquid. The washing liquid is present in the washing space 3. There may be a constant water flow at the feed location 2, such as to flush all keratin materials into the washing apparatus 1.

The wash liquor comprises a major amount of water (e.g. greater than 80 wt%, 90 wt% or 95 wt%) and optionally other ingredients such as one or more surfactants. In one embodiment, the wash liquor comprises a surfactant, for example, to remove fat from feathers. When washing feathers and/or down for the down industry, a washing liquid comprising a surfactant is preferred. In a preferred embodiment, the wash liquor does not comprise a surfactant, more preferably the wash liquor consists of water. Surfactant-free wash solutions are preferred when the keratin materials are subsequently subjected to a hydrolysis process as described elsewhere herein, which is often the case when the keratin materials are smelted for use in the animal feed or pet food industry. The skilled person will appreciate that during use the washing liquid is contaminated such that the composition of the fresh washing liquid before use is referred to herein.

Biogenic amines present in the keratin materials will at least partially dissolve into the washing liquid. In addition, the wash liquor may be used as a transport material to separate materials having a density greater than the wash liquor. For example, feathers will typically float in water, while more dense objects (such as other body parts or sand particles) sink in water. Materials having a density greater than the wash liquor as referred to herein are typically body parts, plucking fingers, sand and/or dirt. In a preferred embodiment, the material having a density greater than the wash liquor is a plucking finger.

The feeding means may comprise a sorter so that the keratin materials are fed into the washing device 1 as discrete pieces, for example so that the keratin materials do not adhere to each other. In this way, the contact surface of the keratin materials is increased and the washing liquid present in the washing device 1 can reach around the discrete pieces of keratin materials.

As another way of increasing the contact between unwanted material in the keratin material and the water particles, a high flow-through rate of the washing liquid may be used. For example, the water in the washing apparatus 1 is entirely updated ten to twenty times per hour or more. For example, in a washing apparatus 1 comprising a washing space 3 containing six cubic meters of water, 100 cubic meters of water can be updated per hour. The washing liquid system comprises an inlet and an outlet of the washing space 3. There may be a plurality of inlets and outlets such that the inlets and outlets are not only used for feeding water to the washing space 3 and extracting water from the washing space 3, respectively, but these inlets and outlets may also be used for shaping the water flow in the washing space and/or exerting a force on the keratin materials via the inlets at high pressure to remove unwanted particles.

The washing liquid leaving the washing space 3 can be disposed of or more preferably partly, largely and/or completely recycled using a recycling system. The recirculation system may be part of a wash liquor system. The recirculation system may return the washing liquid to the washing space 3 or may actively filter and clean the washing liquid before returning the washing liquid to the washing space 3. The washing liquid to be recycled may first pass through several filters, so that the recycled washing liquid is cleaner than when it leaves the washing space, i.e. there is less unwanted material in the washing liquid. The filter may be made of one or several sieves placed in sequence along the flow path and/or substances that extract unwanted molecules from the washing liquid by chemical reactions. The screen may have openings of different sizes (e.g., decreasing in order along the screen).

There may be a water reservoir 30 containing a certain volume of water that may be used in the washing space 3. Fresh water not used by the washing apparatus 1 for cleaning keratin materials may be fed to the reservoir 30. The water level in the reservoir 30 may be controlled, for example, by supply valves, overflow systems and outlet valves. The water pump 31 may work together with a valve system and a pipe system 32 to feed washing liquid from the reservoir to the washing space 3.

A specific inflow of wash liquid into the wash space may be maintained through the use of the reservoir 30. Furthermore, if the water reservoir 30 is used in combination with a filter, such as the filter system 20 described in detail below, water may be circulated from the washing space 3 to the water reservoir 30 via the filter conduit 29 and back to the washing space 3 by reusing the filtered washing liquid.

The washing liquid, preferably water, may be introduced into the washing space 3 using a metering nozzle which ensures that the water level in the washing space 3 remains constant during operation of the washing apparatus 1. When recycled water is used, a screen may be used at the inlet of the recycling system in order to prevent larger particles of keratin material or unwanted material from clogging the metering nozzle.

The washing liquid leaving the washing space 3 can be continuously removed from the washing apparatus 1 in a continuous bleed-off, and at the same time fresh washing liquid can be continuously added to the washing space 3. In this way, the washing liquid contained in the washing space 3 is continuously removed of contaminants and is thus cleaned. This continuous discharge of washing liquid 3 and simultaneous continuous addition of fresh washing liquid can be carried out at the same time as the washing liquid leaving the washing space 3 is partly or largely recirculated using a recirculation system.

The water level in the washing apparatus 1 may be monitored by means of, for example, a pressure sensor. When it is determined that the water level is too low, cleaning water is added to the washing apparatus 1. Such clean water may come from an external water pipe or be recirculated water.

In a preferred embodiment, a wash liquor solids separation system, such as a filter system 20, is mounted above the wash space 3. The filter system 20 may include a static screen with wedge wires having a particular slot size such that water may pass through the wedge wires, but keratin materials typically cannot pass through the wedge wires. For example, the stationary screen may form an arcuate screen. Any other filter system may be used. The water pump pumps the washing liquid from the washing space 3 and feeds it to the filter. The clean washing liquid can flow back into the washing space 3 or the water reservoir 30. The filtered keratin materials are reintroduced into the washing space 3.

The integrated filter may have an automatic cleaning system. The automated cleaning system may include a reciprocating spray arm with a nozzle (e.g., a flat nozzle) that may be periodically moved in a horizontal direction along the rear of the filter. The spray arm may be driven by a spindle which is connected to a motor, for example a motor located on one side of the machine. The direction of rotation of the motor and the linear movement of the spray arm can be controlled by two inductive proximity switches.

In a preferred embodiment, there are stairs 21 and a platform 22 which allow access to a washing liquid-solid separation system, such as a filter system 20, mounted above the washing space 3. In this way, the filter system 20 can be easily maintained.

In a preferred embodiment, by placing a wash liquor solids separation system (e.g., filter system 20 with a large mesh screen) directly above the wash space 3, the reject of the filter system 20 may fall back into the wash space 3. The reject of the filter system 20 may comprise keratin materials, such as feathers. The keratin materials are then led back into the washing space 3. The washing liquid passing through the filter system 20 may be recirculated and reintroduced into the washing space 3, for example via one or more spray bars 40 introduced below, and may be filtered through small mesh screens. A large mesh filter may be used to prevent the nozzle 41 of the spray bar 40 from being clogged. When the foreign material sinks low enough to reach the extraction system 8 discussed below, the foreign material is eventually 'permanently' removed. Keratinized material remains circulated and feathers are eventually removed by continuing the process and material with a high density is eventually sinking and removed by the extraction system 8.

In addition, factory floor space may be saved by placing a wash liquid solids separation system (e.g., filter system 20) directly above the wash space 3. In another embodiment, a wash liquid solids separation system (e.g., filter system 20) may be placed in close proximity to wash space 3, or any other placement configuration may be used. In another embodiment, by placing a wash liquor solids separation system (e.g., filter system 20) directly above the wash space 3, the wash liquor may partially flow through the filters in the filter system 20 and then fall back into the wash space 3. In this way, recirculation and turbulence is created in the upper layer of the washing space 3, in which the most keratin materials are generally found. The washing liquid-solid separation system (e.g., the filter system 20) may block foreign materials and thus clean the washing liquid reintroduced into the washing space 3. In this way, the keratin materials are subjected to a recycled washing liquid which contains less unwanted materials, such as, for example, biogenic amines, and can therefore better absorb the unwanted materials.

Fig. 6 to 7 schematically show the washing space 3 and the feeding and discharging of the washing space 3.

The washing space 3 comprises at least one washing structure which shakes the washing liquid and/or causes turbulence in the washing liquid present in the washing space. A suitable and preferred washing arrangement is a washing roller 4, which is rotated via a motor 43 imparting a rotational movement to the washing roller 4 or via a flow of washing liquid. The washing roller 4 is formed as a drum partly and/or completely immersed in the washing liquid and is made of stainless steel or any other metal or hard and wear-resistant plastic. The longitudinal axis of the drum may be placed, for example, horizontally or vertically, preferably horizontally. Any other shape or material is within the scope of the present invention. Preferably, the material is non-reactive with the wash liquor. The washing roller 4 comprises, for example, paddles, brushes or other protrusions 5 in a radially outward direction, preferably made of the same material as the washing roller 4. The protrusions 5 may be used to push the keratin material forward along the washing space, push the keratin material under water and/or apply turbulence on the washing liquid. In this way, the keratin materials are better separated and the chaotic water flow allows better separation of the keratin materials from unwanted particles and fractions. The inventors have found that an advantage of using such a system is that better separation of keratin materials is achieved, which is particularly useful when unwanted material is trapped inside the feather mass. In one embodiment, five scrub rollers 5 are used, however the invention is not limited in this way.

The rotational speed of the washing roller 4 can be controlled. The higher the rotational speed, the more turbulence is induced in the wash liquor. The rotation speed may be set to about 30 rpm or more, preferably about 40 rpm or more, more preferably 50 rpm or more, and still more preferably about 60 rpm or more. The rotational speed may generally be about 5 revolutions per minute or more, preferably about 10 revolutions per minute or more.

The washing roller 4 may impart a partial and/or substantial cyclonic motion to the washing liquid and the keratin materials at certain locations in the washing space 3, or in any other way impart a motion to the washing liquid such that the keratin materials pass through the same points in the washing space 3 a plurality of times. In this way, the keratin materials stay in the washing space 3 longer, thus prolonging the residence time of the keratin materials in the washing liquid and thus increasing the chance that unwanted molecules or particles can be absorbed or separated by the water.

Instead of the washing roller 4, other washing structures may be used which shake the washing liquid containing the keratin materials, push the keratin materials under water and/or in another way induce turbulence in the washing liquid flow.

The washing space 3 may be divided into one or more functional areas. In the preferred embodiment, the washing space 3 is divided into a sink zone 6 and a further cleaning zone 7. Preferably, the sink zone 6 and the cleaning zone 7 are positioned such that the keratin materials first enter the sink zone 6 before entering the cleaning zone 7. In other words, preferably, the sinking zone 6 and the cleaning zone 7 are consecutive to each other.

When the keratin materials first enter the washing space 3, the keratin materials enter the sinking zone 6. In the sink zone 6, the keratin materials thus still have the highest amount of unwanted material present. If the keratin material is a light material such as feathers, down or the like, it will float in the water or remain higher in the sink zone 6. However, denser materials (such as, for example, chicken heads or plucking fingers) will sink to the bottom of the sink-zone 6 where they can be extracted.

Fig. 8A, 8B, 9, 10 show detailed schematic views of the sinker 6. Figure 11 shows a detailed schematic side view of the sinker 6.

The sink zone 6 may include one or more spray bars 40, or may impart a sinkAny other flow system in which the wash liquid in the zone flows. The flow may be imparted by a liquid and/or a gas, preferably water and/or air. Typically, the flow system will include one or more nozzles that direct a flow of liquid and/or gas that imparts a flow of wash liquid in the sink zone. This flow of washing liquid is preferably directed upwards, but may also be directed sideways, for example. The liquid and/or gas flow rates are chosen in such a way that the keratin materials are suspended in a large amount of washing liquid, while the heavier particles and/or objects still sink to the bottom of the sink zone, so that these particles and/or objects can be extracted by the extraction system 8. The flow may be sized and directed to have a flow of greater than 1.01g/cm ³ Preferably greater than 1.08g/cm ³ Is sinking while most keratin materials remain suspended in a large amount of washing liquid.

In order to achieve good suspension while sinking of the material with a higher density, the flow rate and/or the specific nozzle design and/or the specific nozzle arrangement imparted to the washing liquid by the flow system can be adjusted.

In a preferred embodiment, in which a wash liquor solids separation system, such as filter system 20, is placed directly above wash space 3, wash liquor may fall directly from filter system 20 into wash space 3. This produces a downward flow of wash liquor in this region. The spray bar 40 may be arranged to resist such downward flow so that the keratin materials do not sink toward the extraction system due to the downward flow created by the wash liquid from the filter system 20.

In a preferred embodiment, the flow system (e.g. spray boom) is removable without the need to completely empty the washing space 3. This improves the convenience of maintaining the washing apparatus 1 because the spray bars 40 can be easily cleaned or replaced without removing all of the washing liquid from the washing space 3. One or more spray bars 40 are connected to a flow system valve 42. The flow system valve 42 may be opened or closed to allow or disallow the flow of wash liquid toward the one or more spray bars 40, respectively. Once the flow system valve 42 is closed, the one or more spray bars 40 connected thereto may be disassembled and removed.

The sinker 6 may preferably have a conical or pyramidal shape, or may have another shape converging towards the bottom and/or forming a groove 61 in the bottom. In this way, denser material accumulates at the bottom of the sink zone 6 and is more easily extracted from the washing space 3 by the extraction system 8. If the bottom surface 62 of the submerged area 6, which is farther than the extraction system 8, is also inclined towards the extraction system 8, material submerged at a later stage during washing can still be extracted by the extraction system 8.

The extraction system 8 may be, for example, a spiral extractor which recovers solid material only via a significantly upward rotational movement, but does not extract water or recover water at a later stage and return the water to the washing space 3 via a recirculation system. For example, the extraction system 8 (such as a spiral extractor) may be operated continuously or aperiodically if the sensor indicates that the amount of material to be extracted reaches a predetermined threshold or if a certain control time for which the extraction system 8 is activated has elapsed. The material extracted by the extraction system 8 may be transported to a waste processing unit, such as a waste container. In this way, foreign material is removed when it has sunk low enough to reach the extraction system 8.

In a preferred embodiment, the extraction system comprises a first substantially horizontal spiral extractor and a second spiral extractor that recovers solid material via a substantially upward rotational movement. The first spiral extractor may thus transfer the solid material to a foreign material extraction zone. The foreign material extraction zone may be in fluid communication with the washing space 3, allowing water to flow back into the washing space 3. The second spiral extractor, which recovers the solid material from the foreign material extraction zone via a significantly upward rotational movement, does not extract the water or recovers the water at a later stage and returns the water to the washing space 3 via a recirculation system.

Fig. 12 shows an exemplary appearance of the sinker 6.

An exemplary conduit of the liquid supply system is shown, which leads to a boom forming a flow system in this example. Two manual control valves 42 are shown for limiting the flow rate to the flow system or virtually completely closing the flow system. These valves 42 may also be made electronically controlled, for example by an operator or a control system.

Further, a motor 43 for rotating the washing roller 4 may be installed on the outer wall of the washing space 3. The motor 43 may be controlled manually or electronically and may thus be frequency controlled.

The cleaning zone 7 is formed further away from the inlet point of the feeding device for feeding keratin materials to the washing space. The washing zone 7 and the sinking zone 6 may be partially separated by a separation structure such that the washing space 3 is physically divided into two zones. The separation structure may be placed high enough that denser material (such as certain unwanted particles sinking into the wash liquor) cannot flow beyond the separation structure. However, keratin materials that require further processing may flow beyond the separation structure, for example, because keratin materials overflow the separation structure. The separation structure may be a wall-like structure or a sudden change in the bottom height of the washing space 3. Such separation is not required if the sinking zone 6 is long enough and shaped in such a way that unwanted particles sink towards the extraction system 8 (e.g. by an inclined bottom surface); this is because when the washing liquid reaches the washing zone 7, it is unlikely that any dense material will remain in the washing liquid.

At least one washing structure as described earlier herein may be located in the sink zone 6 and/or the cleaning zone 7. Preferably, the sink zone and the cleaning zone each comprise at least one wash structure, which may be the same or different wash structures. It is highly preferred that the sinking zone 6 and the cleaning zone 7 each comprise at least one washing roll 4 as described earlier herein for the washing space 3.

The washing zone 7 may comprise further washing rolls 4 or other washing structures for the sink zone 6. Since the sink zone 6 comprises an extraction system for densified unwanted particles, the washing liquid will comprise fewer of these densified unwanted particles. The washing liquid flow may encircle the cleaning zone 7 such that the keratin materials stay in the cleaning zone 7 longer.

The sink zone 6 and the cleaning zone 7 may have shared inlets and outlets for the washing liquid as part of the washing liquid system. Alternatively, the sinking zone 6 and the cleaning zone 7 have separate inlets and outlets. In this way, the washing zone 7 mainly comprises washing liquid which has not been contaminated by the initial cleaning in the sink zone 6 and which can be cleaned more effectively. The sinking zone 6 and the washing zone 7 may share a recirculation system of the washing liquid, or the sinking zone 6 and the washing zone 7 may have separate recirculation systems. The washing liquid may have a different composition in the washing zone 7 than in the sinking zone 6. The sink zone 6 and the wash zone 7 may be connected in such a way that the wash liquid flows from the wash zone 7 to the sink zone 6. Alternatively, the wash liquid stream may be such that unwanted particles remain in the sink zone 6 and do not enter the cleaning zone 7. Alternatively, the sink zone 6 and the cleaning zone 7 do not share a fluid connection, i.e. the washing space 3 comprises an unconnected zone. In this case, the keratin materials may travel between the unattached regions via a transport system (such as a conveyor belt).

The wash liquor may remove one or more contaminants from the keratin materials. The contaminant may preferably be selected from the group consisting of: a compound contributing to the Total Volatile Nitrogen (TVN) content; h ₂ S, S; fat; and/or combinations thereof. Preferably, the one or more contaminants are selected from the group consisting of: biogenic amine, H ₂ S, fat, ammonia (NH) ₃ /NH ₄ ) And/or combinations thereof. More preferably, the one or more contaminants are selected from the group consisting of biogenic amines. Biogenic amines are, for example, tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine.

By washing the keratin materials in the washing liquid using the washing system, one or more contaminants may be dissolved into the washing liquid and/or at least partially removed from the keratin materials by the washing liquid. In a preferred embodiment, the wash liquor may solubilize one or more biogenic amines.

In a preferred embodiment, the washing is performed such that the amount of at least one of the contaminants comprised in the pretreated keratin material is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material prior to washing, wherein the amount is determined as w/w on a dry weight basis.

In a preferred embodiment, the one or more contaminants are selected from the group consisting of: biogenic amines, preferably tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and/or agmatine.

In a preferred embodiment, the washing is performed such that the amount of at least one of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine comprised in the pretreated keratin material, preferably the amount of putrescine and/or cadaverine and/or tyramine is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material before washing, wherein the amount is determined as w/w on a dry weight basis.

In a preferred embodiment, the combined amount of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine comprised in the pretreated keratin material, preferably the combined amount of putrescine and/or cadaverine and/or tyramine is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material before washing, wherein the amount is determined as w/w on a dry weight basis.

The keratin materials travel through the washing space 3 in such a way that at least 50%, preferably at least 60%, more preferably at least 70%, more preferably at least 80% of the total amount of one or more contaminants is removed when the keratin materials are extracted from the washing space 3.

Typically, no more than 95% of the total amount of one or more contaminants (particularly one or more biogenic amines) will be removed, and removal of about 80% may often be sufficient to obtain, for example, high quality hydrolyzed feathers or down suitable for the down industry. The total amount of the one or more contaminants, in particular the one or more biogenic amines, remaining after washing is preferably less than 250ppm, more preferably less than 100ppm, more preferably less than 50ppm, on an absolute basis. The amount can be determined by standard HPLC methods.

In a preferred embodiment, the operator selects a predetermined threshold for the different biogenic amines such that when the amount of one or more biogenic amines falls below this predetermined threshold, pretreated keratin materials are obtained from the washing system. For example, the operator selects predetermined thresholds for putrescine, cadaverine, and/or histamine, respectively. The predetermined thresholds for putrescine, cadaverine and/or histamine need not be equal to each other. The predetermined threshold for putrescine may be 50ppm, more preferably 40ppm, more preferably 25ppm, more preferably 10ppm. The predetermined threshold of cadaverine may be 50ppm, more preferably 40ppm, more preferably 25ppm, more preferably 10ppm. The predetermined threshold for histamine may be 50ppm, more preferably 40ppm, more preferably 25ppm, more preferably 10ppm.

The operator may conduct experiments during the setup phase such that the time required to reach a predetermined threshold of contaminants (e.g., the total amount of biogenic amine, e.g., the amount of a particular biogenic amine) in the wash space 3 at a particular machine operation setup may be determined. For example, the operator may determine the amount of contaminants in the keratin materials (e.g. on a dry matter basis) prior to washing, then wash the keratin materials using a specific recirculation rate and discharge rate for the washing liquid (e.g. for the washing liquid present in the washing space 3), for a certain amount of time, and finally determine the amount of contaminants left in the keratin materials after the end of said certain amount of time.

As a further alternative, further processing steps, such as hydrolysis, may be carried out before determining the contaminant content of the washed keratin material, and the amount of contaminants present in the semi-finished product or finished product may be determined. Based on such measurements, it may be determined the amount of time it takes for the keratin materials to be in the washing space 3 using a specific recirculation rate and release rate for the washing liquid (e.g. for the washing liquid present in the washing space 3) in order to reach a predetermined threshold. The recalibration process may be performed after a certain amount of time to ensure that the washing apparatus 1 is still operating with the correct settings.

Alternatively, the amount of biogenic amine dissolved in the wash liquor may be determined. This can be compared, for example, with the amount of biogenic amine present in the keratin materials before they enter the washing device 1.

In a preferred embodiment, the amount of biogenic amine present in the washing liquid in the washing space 3 can be measured, for example, by using a sensor, and such measurement can be used in the control loop of the washing liquid system and the recirculation system. The sensor placed in the washing apparatus 1 (either in the washing space 3 or in the washing liquid system) can determine the amount of biogenic amine absorbed in the washing liquid during operation of the device and can adjust the flow rate, feed rate or extraction rate based on the sensor readings. The inflow and outflow of the wash liquor may be controlled in such a way that the amount of biogenic amine in the wash liquor remains below a certain predetermined threshold. The washing liquid flowing into the washing space 3 may be washing liquid that has not been used yet or recycled washing liquid, so that such washing liquid flowing into the washing space 3 contains less biogenic amine than the washing liquid used in the washing space 3. Since the washing liquid flowing into the washing space 3 contains less biogenic amine, and since the used washing liquid in the washing space 3 can be removed, in this way, the amount of biogenic amine contained in the washing liquid in the washing space 3 can be reduced and effectively controlled.

The amount of keratin materials per hour pretreated by the washing apparatus 1 may be greater than or equal to 0.5 metric ton/hour, preferably greater than or equal to 1 metric ton/hour, more preferably greater than or equal to 2 metric ton/hour. The mass of the pretreated keratin material is defined herein based on the total weight (including moisture).

The washing can be carried out in a washing space in which the amount of washing liquid present in the washing space is greater than or equal to 1m ³ Preferably greater than or equal to 2m ³ Greater than or equal to 2.5m ³ . The recirculation of the entire volume of washing liquid may be at least 5 times per hour, preferably at least 10 times per hour, more preferably at least 15 times per hour. Preferably, the recirculation is performed by withdrawing the washing liquid at the end of the washing space 3, for example at or substantially close to the tapping point where the tapping means 9 is located, and at the same time reintroducing the washing liquid at the feeding point 2 via the flow system. Preferably, the washing liquid is reintroduced at the feed location 2 simultaneously and via a spray bar 40 located in the sink zone 6.

In a preferred embodiment, (i) the wash liquid is reintroduced at the feed location and via a flow system (e.g., a spray bar); (ii) Drawing off washing liquid at the end of the washing space 3, for example at the tapping point or substantially close to the tapping point; and (iii) a washing structure, in particular a washing roll 4, more in particular a rotating pulp drum, imparting a flow from the feed location towards the discharge location. These three effects cause a flow moving from the feed position to the discharge position, thereby propagating the feathers through the washing space 3. The flow may be a linear flow.

The keratin materials may flow through the washing space 3 several times, but preferably one channel is sufficient to obtain a consistently high quality.

After the washing has been completed, the outfeed device 9 obtains keratin materials from the washing apparatus 1. The outfeed device 9 may comprise a screw conveyor, a conveyor belt, a pump, a trommel screen and/or a rotary screen. The conveyor belt may comprise a screen or perforations so that any washing liquid carried away by the outfeed device 9, for example, may be returned to the washing space 3. A spray bar or another type of nozzle may be used to flush the product with a clean wash liquid (e.g., water).

The moisture content of keratin materials, such as feathers, is generally higher than 50% at the outfeed 9 and may be up to 80% moisture. Such high moisture content may be less advantageous in further processing, for example for some types of hydrolyzers. In a preferred embodiment, the keratin materials (preferably feathers) are subjected to a physical dehydration step. This dewatering can be done on perforated belts or by pressing the keratin materials in a screw press. For example, one or more feed screws may be used to feed the feathers appropriately to the hydrolyzer. In the dewatering step, the water content is preferably reduced to less than 70% by weight, even more preferably to less than 65% by weight, relative to the amount of keratin materials.

Furthermore, in a preferred embodiment, the liquid extractor 10 may be positioned such that it acts on the keratin materials extracted from the washing space 3 by the outfeed device. The liquid extractor 10 extracts excess liquid from the keratin materials and thus acts as an excess wash liquid removal device. An excess wash liquor removal device (e.g., liquid extractor 10) may help reduce the moisture content of the keratin materials at the outfeed device 9 after exiting the wash space 3. The liquid extractor 10 may comprise a pressing device, a drying system, an air knife or air knife, a suction system (e.g., a belt) below the outfeed device 9, any other suitable device that may extract excess liquid from the keratin materials before they are further processed, or any combination thereof. If, for example, a conveyor belt is used as the outfeed device 9, the length of the outfeed belt may be too great, such as to dewater the washing product as much as possible. For cleaning the belt, a rotary scraper may be installed.

Excess liquid extracted from the keratin materials by the excess wash liquid removal device (e.g., liquid extractor 10) may be recycled to the wash space 3 by recirculating water using a recirculation system. The recirculation system may return excess liquid to the washing space 3 or may actively filter and clean the excess liquid before returning it to the washing space 3. Thus, excess liquid is included in the overall mass balance of the washing liquid circulating in the machine.

The collection bin 11 may be used to collect the washed keratin materials. The keratin materials can also be positioned directly from the outfeed device 9 on a transport system that transports the keratin materials towards, for example, a hydrolysis system.

Fig. 13 shows a flow chart depicting various steps in the (pre) processing 100 of keratin materials, according to the invention.

In a first step 101, keratin materials are fed to a washing device 1. Keratin materials may have undergone a variety of processing steps, whether chemical or physical in nature. Preferably, however, the first step 100 is first performed after the keratin materials have been collected, for example at a slaughterhouse, before any other processing steps have taken place.

In a second step 102, the keratin materials are washed in the washing device 1 using an aqueous washing liquid as described earlier herein. This can be done, for example, as described in relation to the operation of the washing apparatus 1. The washing liquid may dissolve and/or at least partially remove certain contaminants present on the keratin materials. For example, the wash liquor may solubilize certain biogenic amines that may be present in the keratin material and may be anti-nutritional when digested. The washing may be performed in a plurality of sub-steps. The sub-step may be a sinking step in which material having a density greater than the wash liquor sinks below the keratin material and is then extracted at a point below the location of the keratin material. The sub-step may be a washing step, wherein the keratin material that has undergone a rougher cleaning is further cleaned. The different sub-steps may be independent in terms of the washing liquid used, the flow rate and other settings of the washing apparatus 1.

In a third step 103 it is checked whether the amount of one or more contaminants (e.g. biogenic amines) present in the keratin material falls below a predetermined threshold. The amount of one or more contaminants (e.g., biogenic amines) can be measured by measuring the amount of contaminants absorbed by or present in the wash liquor or by measuring the amount of one or more contaminants (e.g., biogenic amines) present in the keratin material from, for example, a sample. When it is detected that the predetermined threshold is reached, keratin materials may be extracted from the washing device 1. Furthermore, tests may be performed in advance to determine the settings of the washing device 1 and the washing time necessary to make the keratin materials have an amount of one or more contaminants below a predetermined threshold. After such a predetermined time has been exceeded, keratin materials may be extracted from the washing device 1.

In an optional fourth step 104, the keratin material may be subjected to further processing steps. The material may be dried to extract excess wash liquor from the keratin material. In a preferred embodiment, other processes that may be performed include hydrothermal and pressure treatment processes; acid, base and/or enzymatic hydrolysis methods; or a combination thereof. Keratin materials are often incompletely hydrolyzed to single amino acids to improve digestibility. In another embodiment directed to down for the down industry, other processing steps include, for example, bagging down for transport and/or using down in, for example, clothing, blankets, and other textiles.

The invention therefore also relates to a process for producing hydrolysed keratin materials, comprising the steps of:

(i) Washing the keratin material using a washing system as described above or a method as described above;

(ii) Hydrolyzing the keratin material;

Hydrolysis and drying may be carried out as described, for example, in US5772968, US4286884, US4172073, EP 2832236, EP 2832237, EP 3192377.

Suitable hydrolysis processes using steam and pressure are as follows: in a preferred process, the partial hydrolysis of the keratin materials in step (i) of the process of the invention will be as follows: the hydrolysis stage is preferably operated by (a) loading raw feathers or other keratin materials onto a continuous or discontinuous vertical or horizontal hydrolyzer, optionally together with raw blood (in the case of raw feathers, these raw feathers have a moisture content of for example between 55% and 70%) (b) heating the hydrolyzer by means of a steam jacket (and/or injection of direct steam), whereby a pressure is generated as a result of evaporation of water and/or direct steam injection, maintaining the pressure between about 2 bar and about 100 bar, preferably between about 2 bar and about 15 bar, and more preferably between 2 bar and 8 bar, for a time of 5 seconds up to 240 minutes, preferably between 90 seconds up to 30 minutes, more preferably between 5 minutes and 40 minutes, and most preferably between 10 minutes and 30 minutes, and (c) depressurizing and discharging to the drying stage.

Drying can be carried out in a variety of ways, for example in presses, tray dryers, drying belts, fluidized beds, air turbulence mills, etc. In a preferred embodiment of the invention, the mixture leaving the hydrolyzer, wherein part of the water evaporates due to the pressure drop, is subjected to a pressing step. In this step, a portion of the water from the keratin materials is removed to a water content of, for example, about 65% to about 45% by weight.

In a preferred embodiment, the partially hydrolysed material resulting from step (i) is dried in a way that allows for low thermal damage such that the reduction of the digestibility of the keratin material is limited and characterized in that the pepsin and/or ileal digestibility remains higher than 80% and 85% (preferably about 85% or higher), 82% and 90% respectively, and more preferably about 85% and 92% or higher, respectively. More preferably, the reduction in pepsin and/or ileal digestibility measured before and after the drying step is preferably less than 5%. In order to obtain such a material with low thermal damage, the material is dried with an air stream while being ground. By using an air turbulence mill a high in vitro digestibility of the keratin material and very suitable material characteristics can be achieved, since small particles generated by the grinding action contribute to a rapid drying of the hydrolysed material.

Thus, preferably, an air turbulence mill is used, while the partially hydrolysed material resulting from step (i) is dried and milled with a stream of air, typically air (which may be low oxygen). The air turbulence mill has the benefit of a rapid grinding and drying effect and the use of the air turbulence mill according to the invention results in drying and simultaneously grinding or milling of the keratin material by introducing the material to be dried and a stream of air (typically air) into the high speed rotor within the closed chamber.

In alternative embodiments, the drying process includes drying under reduced pressure such that the temperature of the material is maintained at a temperature of less than about 90 ℃, preferably at a temperature of about 80 ℃ or less, and more preferably at a temperature of about 75 ℃ or less, such as, for example, a temperature between about 60 ℃ and about 75 ℃, or, for example, at a temperature of about 70 ℃ or less. This drying process may be performed in a tray dryer under vacuum.

In another embodiment, the drying process is included in a stream of hot air, such as in a fluid bed dryer, a loop dryer, a drum dryer, or the like, effective to cause turbulence to the keratin materials. In this case, it is also important to limit the thermal exposure to a minimum. Thus, during a short period of time (e.g., about 60 seconds or about 30 seconds), the material may be at a temperature of about 100 ℃ or about 120 ℃. Typically, the maximum temperature of the short time heat exposure will be about 150 ℃ or less, or preferably about 120 ℃ or less. When relatively low water is present, relatively high temperatures may be present, as the combination of water and heat appears to be the most damaging.

In another embodiment, a method for processing keratin materials for the down industry comprises the steps of:

(i) Washing down-containing keratin materials using the washing system or the method described above;

(ii) Drying the washed keratin materials;

Two or more of the above embodiments may be combined in any suitable manner.

Examples

Biogenic amines can be measured using HPLC methods known in the art. Volatile basic total nitrogen according to EC regulations 2074/2005 or 152/2009. Ammonia nitrogen can be measured according to EC regulations 152/2009.

The feathers were washed using the washing apparatus described above and shown in the figures. Good separation between the foreign material and feathers was found. In addition, a substantial reduction in biogenic amine content in feathers was observed. The amounts of putrescine and cadaverine were reduced from greater than 100ppm and greater than 180ppm, respectively, to less than 30ppm, respectively. The total amount of biogenic amines represented by agmatine, cadaverine, histamine, phenethylamine, putrescine, spermidine and tyramine was reduced from more than 400ppm before washing to less than 200ppm after washing. The ppm values mentioned in this example are w/w and are based on dry weight.

Example 2

Washing 5.9m using the washing apparatus described above and shown in the drawings ³ Feathers. 150 large fragments or whole plucked fingers were recovered, which weighed 4254g in total. 71 medium sized chips and 12 small chips were recovered, with a total weight of 1090g. Thus, a total of 5344g was recovered.

A screen was placed to recover the remaining debris from the feathers. 16 large blocks, 16 medium-sized blocks and 4 small blocks were recovered, totaling 962g. The recovery from the chips was thus 87% and the recovery from the weight was thus 85%.

In addition, a large number of chicken heads, legs and feet were recovered. Very little feathers are extracted by the screw.

Thus, the washing apparatus shows good selectivity for removing foreign material from feathers.

Example 3

Washing about 25m using the washing apparatus described above and shown in the drawings ³ Over a period of 4 days. 822 plucking fingers or fragments thereof were removed during this period, totaling 18kg.

Claims

1. A washing system suitable for continuous processing, suitable for pre-treating keratin materials, preferably feathers, hair or wool, comprising:

a feeding device for feeding the keratin materials to the washing system;

wherein the washing space comprises a sink zone wherein material having a higher density than the washing liquid sinks under the keratin materials;

at least one washing structure that shakes the washing liquid and/or induces turbulence in the washing liquid present in the washing space;

-a discharge device for extracting the keratin materials from the washing system.

2. The washing system of claim 1, wherein the sink zone comprises a flow system that is adapted to impart a flow to the washing liquid in the sink zone, wherein the flow is sized and directed such that the keratin materials remain suspended and move away from the extraction system while the material having a density greater than the washing liquid remains sink toward the extraction system.

3. The washing system according to claim 1 or 2, wherein the washing space further comprises a cleaning zone for cleaning the keratin materials, the sink zone and cleaning zone being positioned such that the keratin materials first enter the sink zone before entering the cleaning zone, wherein at least one washing structure is located in the cleaning zone.

4. A washing system according to any one of claims 1 to 3, wherein the washing liquid system further comprises a washing liquid recycling system for recycling the washing liquid after use in the washing space, wherein the washing liquid recycling system comprises a washing liquid solids separation system, preferably a filter, for cleaning the washing liquid.

5. The washing system according to any one of claims 1 to 4, further comprising an excess washing liquid removal device for extracting excess washing liquid from the keratin material after the keratin material has been washed in the washing space, preferably wherein the excess washing liquid removal device extracts the excess washing liquid at the discharge device and/or wherein the extracted excess washing liquid is reused in the washing space.

6. A washing system according to any one of claims 1 to 5, wherein the washing structure is cylindrically shaped and comprises one or more protrusions on the cylindrical surface, and wherein the washing structure is rotatably mounted on the washing system, preferably mounted such that the keratin material is at least partially submerged due to the effect of the protrusions when the washing structure is rotated.

7. The washing system of any one of claims 1 to 6, wherein a bottom surface of the sink zone is inclined towards the extraction system, and/or wherein the extraction system comprises a spiral extractor.

8. A method for pre-treating keratin materials, preferably feathers, hair or wool, comprising the steps of:

washing the keratin materials in an aqueous washing liquid using the washing system, wherein the one or more contaminants are dissolved into the washing liquid and/or at least partially removed from the keratin materials by the washing liquid;

Obtaining pretreated keratin material from the washing system;

characterized in that the washing is performed such that the amount of at least one of said contaminants contained in the pretreated keratin material is below a predetermined threshold.

9. The method according to claim 8, wherein washing is performed such that the amount of at least one of the contaminants contained in the pre-treated keratin material is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material before washing, wherein the amount is determined as w/w on a dry weight basis.

10. The method of claim 8 or 9, wherein the one or more contaminants are selected from the group consisting of: biogenic amines, preferably tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and/or agmatine.

11. The method according to claims 8 to 10, wherein the washing is performed such that the amount of at least one of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine comprised in the pre-treated keratin material, preferably the amount of putrescine and/or cadaverine and/or tyramine is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material before washing, wherein the amount is determined as w/w on a dry weight basis.

12. The method according to any one of claims 8 to 11, wherein the combined amount of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine comprised in the pre-treated keratin material, preferably the combined amount of putrescine and/or cadaverine and/or tyramine is less than 50%, preferably less than 40%, more preferably less than 30%, more preferably less than 20% of its amount in the keratin material before washing, wherein the amount is determined as w/w on a dry weight basis.

13. The method according to any one of claims 8 to 12, wherein the washing of the keratin materials comprises a sinking step, wherein the sinking of the material having a density greater than the washing liquid is lower than the keratin materials and is then extracted at a site lower than the position of the keratin materials.

14. The method according to any one of claims 8 to 13, wherein the washing of the keratin materials comprises keeping the amount of at least one biogenic amine dissolved in the washing liquid below a predetermined threshold by extracting the used washing liquid and supplying fresh washing liquid, preferably by continuously discharging the used washing liquid and continuously supplying fresh washing liquid, preferably keeping the amount of at least one biogenic amine selected from the group consisting of tyramine, putrescine, cadaverine, histamine, phenethylamine, spermidine and agmatine dissolved in the washing liquid below a predetermined threshold.

15. The method according to any one of claims 8 to 14, wherein the wash liquor further comprises a surfactant and/or a biocide and/or a degreasing agent and/or a bleaching agent and/or an organic solvent.

16. The method according to any one of claims 8 to 15, wherein the amount of pretreated keratin material per hour is greater than or equal to 0.5 metric tons/hour, preferably greater than or equal to 1 metric ton/hour, more preferably greater than or equal to 2 metric tons/hour, and wherein washing is performed in a washing space, wherein the amount of washing liquid present in the washing space is greater than or equal to 1m ³ Preferably greater than or equal to 2m ³ Greater than or equal to 2.5m ³ And wherein the total amount of wash liquor is recycled at least 5 times per hour, preferably at least 10 times per hour, more preferably at least 15 times per hour.

17. The method of any one of claims 8 to 16, wherein the washing system is the washing system of any one of claims 1 to 7.

18. A process for producing hydrolyzed keratin materials, comprising the steps of:

(i) Washing the keratin materials using a washing system according to any one of claims 1 to 7 or a method according to any one of claims 8 to 17;

(ii) Hydrolyzing the keratin materials;

19. A method for processing keratin materials for the down industry, comprising the steps of:

(i) Washing keratin materials comprising down using a washing system according to claims 1 to 7 or a method according to any one of claims 8 to 17;

(ii) Drying the washed keratin materials;

20. A method for washing keratin materials, preferably feathers, hair or wool, wherein the keratin materials are contaminated with materials having a density greater than the keratin materials, comprising:

washing the keratin materials in a washing system using a washing liquid, wherein the keratin materials float and wherein the material having a density greater than the washing liquid sinks;

extracting the material having a density greater than the wash liquor at the bottom of the wash system using an extraction system.

21. The method of claim 20, wherein the method further comprises imparting a flow in the washing system, wherein the flow is sized and oriented such that the keratin materials remain suspended and move away from the extraction system while the material having a density greater than the washing liquid still sinks toward the extraction system.

22. The method of claim 21, wherein the flow is sized and directed so as to have a flow of greater than 1.01g/cm ³ Preferably greater than 1.08g/cm ³ Is sinking while most of the keratin materials remain suspended in the washing liquid.