EP4689517A1

EP4689517A1 - New disk design for a disc dryer

Info

Publication number: EP4689517A1
Application number: EP24718423.7A
Authority: EP
Inventors: Per Bonne ERIKSEN; Uffe Christian LUND
Original assignee: Haarslev Industries AS
Current assignee: Haarslev Industries AS
Priority date: 2023-04-06
Filing date: 2024-04-08
Publication date: 2026-02-11
Also published as: CN121263644A; WO2024209111A1

Abstract

The present invention relates to a disc comprising a first flange and a second flange, wherein at least part of the first flange (2) is placed in parallel to, or substantially in parallel to, at least part of the second flange (3) and wherein a first welding (14) is provided between the first flange (2) and the second flange (3) and the first welding (14) extends from an outer periphery of the first flange (5a) and an outer periphery of the second flange (5b) and at least 5 mm and towards an inner periphery of the first flange (6a) and an inner periphery of the second flange (6b).

Description

NEW DISK DESIGN FOR A DISC DRYER

Technical field of the invention

The present invention relates to an improved disc for a disc dryer.

Background of the invention

Different kinds of drying techniques are described for drying water-containing materials and the choice of drying techniques may depend on e.g. the industry, the temperature requirements, the volume, the speed, application of the dried product, or the sensitivity of the product to be dried.

One interesting drying technique is the disc dryer, including several discs built around a rotor comprising of a central hollow shaft fitted with multiple discs, that during operation may be steam-heated. These steam-heated discs apply indirect heat over a very large area, in a compact design that quickly and effectively reduces the water content in the product.

A disc dryer has shown to be an efficient equipment for drying products from various industries like in the rendering industry for drying feathers, blood, bone or meat, etc.; for drying fish meal; for drying products from the food, chemical, or pharmaceutical industry; or the environmental industry, e.g. by drying sludge.

The dryer may be easily sized for both small and large productions.

One of the advantages of the disc dryer may be the increased surface area being heated and capable of being in contact with the product to be dried and the minimal space requirement. The drying method of a disc dryer is based on the heat exchange between the product being in contact with the discs, which are heated by e.g. hot liquid or steam circulation in the interior of the discs.

When using steam in the disc dryer, an efficient purge system may eliminate the condensate inside the hollow shaft of the rotor, ensuring maximum yield. Even steam is the most preferred heating source, oils or other liquids may also be used for heating as well as cooling products.

During operation, the hot fluid medium or the steam flows through the hollow shaft of the rotor and out into the interior of the hollow discs and heats these discs so that the moisture in the material in the chamber (on the outer side of the discs comprising the flow of steam) resulting in evaporation of water from the material coming into contact with the hot surfaces of the discs.

Hence, the large surface provided by the disc dryers may be responsible for the effective heat exchange and the effective drying capacity.

One reason for disc driers demonstrating good properties in relation to drying of wet materials is the way in which these disc driers are constructed. The characteristics of such a disc drier are that it consists of a stationary chamber, and that a rotor comprising a hollow shaft may be arranged inside this chamber, with a number of hollow discs welded perpendicularly onto the central rotor tube. The discs may have a parallel structure at the tip of the disc and an arc form structure at the end attached to the rotor.

At the end of the discs a wearing ring may be installed to increase the wear resistance and to form a support for the attachment of brackets to the disc. The brackets allow attachment a paddle to provide proper movement of the product during drying and towards the discharge outlet, and they may prevent material to be dried to accumulate between the discs.

The paddle according to the present invention may include a paddles, a scraper and/or a shovel.

There is a challenge with the current construction of the discs is that applying a wearing ring at the outer periphery of the dis may be troublesome, time consuming and material consuming, and impose and increased effect of the environment.

Hence, an improved disc and rotor for a disc dryer, and an improved disc dryer as such, would be advantageous, and in particular a more efficient and/or reliable, production of discs (and rotors comprising discs) would be advantageous, that would result in a reduced cavity formation (openings); an increased effectivity of the drying, easier and cheaper manufacturing, improved productivity, high or even higher wear resistance, improved stress level, and more gentle to the environment, would be advantageous. Summary of the invention

Thus, an object of the present invention relates to a disc for a disc dryer, to a rotor for a disc dryer comprising the disc according to the present invention and to the disc dryer a such.

In particular, it is an object of the present invention to provide an improved disc and an improved rotor for a disc dryer, and an improved disc dryer as such, that solves the above mentioned problems of the prior art with efficiency, costs and/or reliability during production of discs (and rotors comprising discs), a disc that suffer from cavity formation (openings); an decreased effectivity during drying, low productivity, and impact on the environment - without compromising important features like wear resistance, and stress level.

Thus, one aspect of the invention relates to a disc comprising a first flange and a second flange, wherein at least part of the first flange may be placed in parallel to, or substantially in parallel to, at least part of the second flange and wherein a first welding may be provided between the first flange and the second flange and the first welding extends from an outer periphery of the first flange and an outer periphery of the second flange and at least 5 mm and towards an inner periphery of the first flange and an inner periphery of the second flange.

A further aspect of the present invention relates to a disc comprising a first flange and a second flange, wherein the first flange may be placed in parallel to, or substantially in parallel to, the second flange and wherein a bracket may be attached directly to an outer periphery of the first flange and/or to an outer periphery of the second flange.

Another aspect of the present invention relates to a disc comprising a first flange and a second flange, wherein the first flange may be placed parallel to, or substantially parallel to, the second flange and wherein an outer periphery of the first flange (5a) and/or to an outer periphery of the second flange may not be provided with a wearing ring.

A further aspect of the present invention relates to a bracket, in particular a bracket for a disc, (preferably, a bracket for a disc for a disc dryer), the bracket comprises a base part and a couplings part, wherein a base-length of the base part is larger than a couplinglength of the coupling part. An even further aspect of the present invention relates to a bracket (in particular a bracket for a disc, preferably, a bracket for a disc for a disc dryer) the bracket comprising a base part and a couplings part, wherein bracket comprises at least one, preferably two, protrusion(s) in the base part relative to the coupling part of the bracket (preferably, in the longitudinal direction of the length of the bracket).

Another aspect of the present invention relates to a disc comprising a bracket according to the present invention.

Yet another aspect of the present invention relates to a rotor comprising a hollow shaft and at least one disc according to the present invention.

Still another aspect of the present invention relates to a disc dryer comprising a rotor according to the present invention and/or a disc according to the present invention.

Description of the figures

Figure 1 shows a disc (1) according to the prior art. The prior art disc (1) may have a first flange (2) and a second flange (3), wherein the first flange (2) may be placed in parallel to, or substantially in parallel to, the second flange (3). The first flange (2) and the second flange (3) comprise an outer periphery of the first flange (5a) and an outer periphery of the second flange (5b). A wearing ring (16) is provided on the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b) to increase the wear resistance of the disc (1) during use.

A bracket (4) is attached to the wearing ring (16) and the bracket (4) may be provided with a paddle (17).

The disc (1) comprises an outer periphery of the first flange and the second flange (5a/5b) and an inner periphery of the first flange and the second flange (6a/6b). The first flange (2) and the second flange (3) comprising an outer end of the first/second flange (7a/7b) and an inner end of the first/second flange (8a/8b) and the inner end of the first/second flange (8a/8b) may comprise an arc shaped form (lOa/lOb).

At the outer periphery of the first flange and the second flange (5a/5b) the first flange (2) and the second flange (3) are welded together by a first welding (14) and welded together with the wearing ring (16). The disc (1) may comprise a cavity (11) and a heating part (13) allowing, e.g. steam, to move around to provide a substantial equal or homogenous temperature over the disc (1) during use.

To improve strength of the disc (1) and to reduce the risk of crack formation the first and the second flanges (2/3) of the discs may be held together by stay bolts (18). Stay bolts (18) may be made by welding holes on both sides of the disc (1) (both in the first flange (2) and in the second flange (3)).

Figure 2 shows a subset (B) of the disc (1) of figure 1 and shows a bracket (4) comprising a paddle (17) attached by fixing means (15). The bracket comprises a base part (20) and a couplings part (21), wherein a base-length (LI) of the base part (20) is the same as a coupling-length (L2) of the coupling part (21).

The brackets traditionally used in the prior art square or rectangular shaped with equal coupling-length (L2) and coupling part (21).

The base-length (LI) may be determined at a surface of the base part (20) facing away from the coupling part (21), preferably in the longitudinal direction of the length of the bracket (4). The coupling length (L2) at the point for coupling the paddles, preferably at the fixing means (15) for attaching paddles to the one or more brackets (4), preferably, in the longitudinal direction of the length of the bracket (4).

The bracket (4) is attached to the wearing ring (16) by a second welding (19) on to the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b) of the disc (1).

Figure 3 shows a disc (1) according to the present invention. The disc (1) may have a first flange (2) and a second flange (3), wherein the first flange (2) may be placed in parallel to, or substantially in parallel to, the second flange (3). A bracket (4) may be attached directly to an outer periphery of the first flange (5a) and/or to an outer periphery of the second flange (5b). The bracket (4) may be provided with a paddle (17).

The disc (1) comprises an outer periphery of the first flange and the second flange (5a/5b) and an inner periphery of the first flange and the second flange (6a/6b). The first flange (2) and the second flange (3) comprising an outer end of the first/second flange (7a/7b) and an inner end of the first/second flange (8a/8b) and the inner end of the first/second flange (8a/8b) may comprise an arc shaped form (lOa/lOb). At the outer periphery of the first flange and the second flange (5a/5b) the first flange (2) and the second flange (3) are welded together by a first welding (14). When making the first welding (14) the depth of the first welding from the outer periphery of the first flange and the second flange (5a/5b) may extend at least 5 mm towards the inner periphery of the first flange and the second flange (6a/6b) causing this outer end of the disc resulting in a wear improved part (12) whereby it is unnecessary to add an additional wearing ring to the outer periphery of the disc (5a/5b) as the disc (1) comprises sufficient wear resistance. The temperature impact when making the first welding (14) may causes the metal of an area of the first flange (2) and the second flange (3) to change structure causing this outer end (7a/7b) of the disc (1) resulting further wear resistance of the disc (1).

The disc (1) may comprise a cavity (11) and a heating part (13) allowing, e.g. steam, to move around to provide a substantial equal or homogenous temperature over the disc (1) during use.

Figure 4 shows a subset (A) of the disc (1) of figure 3 and shows a bracket (4) comprising a paddle (17) attached by fixing means (15). The bracket comprises a base part (20) and a couplings part (21), wherein a base-length (LI) of the base part (20) is the same as a coupling-length (L2) of the coupling part (21).

The brackets (4) comprise a base part (20) and a couplings part (21), wherein a baselength (LI) of the base part (20) is larger than a coupling-length (L2) of the coupling part

(21).

The base-length (LI) may be determined at a surface of the base part (20) facing away from the coupling part (21), preferably in the longitudinal direction of the length of the bracket (4). The coupling length (L2) at the point for coupling the paddles, preferably at the fixing means (15) for attaching paddles (17) to the one or more brackets (4), preferably, in the longitudinal direction of the length of the bracket (4).

The base part (20) and the coupling part (21) are connected by at least one inclining side

(22).

The bracket (4) according to the present invention comprises two protrusions (24) in the base part (20) relative to the coupling part (21) of the bracket (4), preferably, in the longitudinal direction of the length of the bracket (4). The bracket (4) according to the present invention is provided with rounded corners (25) of the coupling part (21), to make instalment, replacement, and substitution easier.

The base part (20) is provided with two legs (23) pointing from the base part (20) and away from the coupling part (21) to improve the second welding (19) between the bracket (4) and the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b).

The bracket (4) comprises a base-surface (26) of the base part (20), and the base-surface is facing away from the couplings part and the base-surface is spherically shaped to improve the fit with the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b) and with the first welding (14) between the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b).

When attaching the bracket (4) to the disc (1) the space provided between the basesurface (26) and the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b) by the legs (23) may improve the second welding (not shown in figure 4).

Figure 5a shows a disc (1) and figure 5b shows a subset (C) of the disc (1) of figure 5a and shows a cross section view of half part of the disc (1) (the other part may be similar); and figure 5c shows a subset (D) of the outer part of the disc (1) of figure 5a and figure 5b, and shows a cross section view of the outer part of the disc (1).

The disc (1) and subsets (C) and (D) comprises a first flange (2) and a second flange (3), wherein the first flange (2) may be placed in parallel to, or substantially in parallel to, the second flange (3). The disc (1) comprises an outer periphery of the first flange and the second flange (5a/5b) and an inner periphery of the first flange and the second flange (6a/6b). The first flange (2) and the second flange (3) comprising an outer end of the first/second flange (7a/7b) and an inner end of the first/second flange (8a/8b) and the inner end of the first/second flange (8a/8b) may comprise an arc shaped form (lOa/lOb). A bracket (4) is attached to the outer periphery of the first flange and the second flange (5a/5b).

At the outer periphery of the disc (5a/5b) the first flange (2) and the second flange (3) are welded together by a first welding (14) with the part of the first welding placed closest to the outer periphery (14a). Preferably, the part of the first welding (14a) may be placed closest to the outer periphery of the disc preferably in alignment with, or substantially in alignment with, the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b). To properly securing the bracket (4) to the disc (1) one or more second welding (19) may be provided.

When making the first welding (14) the size of the first welding (14) may be sufficiently large (preferably 5 mm or more extending from the outer periphery of the first and second flange (5a/5b) to improve wear resistance of the disc (1). Furthermore, the temperature impact may cause the metal of an area of the first flange (2) and the second flange (3) to change structure causing this outer end of the disc resulting in a wear improved part (12) whereby it is unnecessary to add an additional wearing ring to the outer periphery of the disc (5a/5b) as the disc (1) comprises sufficient wear resistance.

Figure 6 shows a plane view of a bracket (4) according to the present invention and figure 7 shows perspective view of a bracket (4) according to the present invention. The brackets (4) illustrated in figures 6 and 7 comprises a base part (20) and a couplings part (21), wherein a base-length (LI) of the base part (20) is larger than a coupling-length (L2) of the coupling part (21).

The base part (20) and the coupling part (21) are connected by at least one inclining side (22).

The bracket (4) according to the present invention comprises two protrusions (24) in the base part (20) relative to the coupling part (21) of the bracket (4), preferably, in the longitudinal direction of the length of the bracket (4). The brackets illustrated in figures 6 and 7 are provided with rounded corners (25) of the coupling part, to make instalment, replacement, and substitution easier.

The bracket (4) comprises a base-surface (26) of the base part (20), and the base-surface is facing away from the couplings part and the base-surface is spherically shaped to improve the fit with the outer periphery of the first flange (5a) and the outer periphery of the second flange (5b).

The present invention will now be described in more detail in the following.

Detailed description of the invention

Accordingly, the inventors of the present invention surprisingly found that by optimizing the disc or a disc dryer (or a heat exchanger) as described herein, the effectivity and productivity of the discs or the dryer comprising the discs may be improved. At the same time the inventors of the present invention found that the process of fitting the discs to the rotor became much easier by the discs according to the present invention.

Disc dryers may be especially suited for drying pasty products or sludge-like products. These dryers can be constructed in carbon steel as well as stainless steel.

Heat transfer in a disc dryer (or in a heat exchanger) maybe provided by means of steam through a heavy central rotor and into the interior of the disc.

Inside the dryer double-walled discs (where one wall may be the first flange according to the present invention and another wall may be the second flange according to the present invention) are sitting on a centralized hollow shaft which may be heated by steam from the inside. The product to be dried may be continuously circulated in the drying chamber by a bundle of rotating disks having paddles fixed at the periphery of the discs and transport the product to be dried axially through the bundle of discs in the dryer.

The disc according to the present invention comprises a disc surface and a central hole placed in the middle of the disc. The disc surface may be defined by the first flange and the second flange.

A preferred embodiment of the present invention relates to a disc comprising a first flange and a second flange, wherein at least part of the first flange may be placed in parallel to, or substantially in parallel to, at least part of the second flange and wherein a first welding may be provided between the first flange and the second flange and the first welding extends from an outer periphery of the first flange and an outer periphery of the second flange and at least 5 mm and towards an inner periphery of the first flange and an inner periphery of the second flange. In an embodiment of the present invention a bracket may be attached directly to an outer periphery of the first flange and/or to an outer periphery of the second flange.

Preferably, the outer periphery of the first flange and/or the outer periphery of the second flange are not provided with a wearing ring.

Another preferred embodiment of the present invention relates to a disc comprising a first flange and a second flange, wherein the first flange is placed in parallel to, or substantially in parallel to, the second flange and wherein a bracket is attached directly to an outer periphery of the first flange and/or to an outer periphery of the second flange.

During use, e.g. in a disc dryer, the peripheral speed of the disk, when rotating, may be larger at the outer periphery of the disc than on the inner periphery of the disk, which may result in a rapidly increased wear of the disc at the outer periphery of the disk, and the outer periphery of the disc may become increasingly worn (relative to the inner periphery of the disc) resulting in the risk of leakage of heat medium, such as steam, from the disc, and it may be necessary to repair the disc or the disc may be discarded, even the other parts of the disc is perfectly suitable to be used.

Solutions in the prior art may solve this problem with increased wear of the outside periphery of the disc, by applying a wear-resistant bar, a wearing ring or another kind of disc-protector which are welded on the outside periphery of the disk to increase wear resistance.

One of the challenges with applying wear-resistant bars or another kind of disc-protectors to the outside periphery of the disc may be that production costs may be increase significantly, heat distortion of the first and/or second flanges may occur resulting in the risk of formation of cavities/openings between the flanges of the disc, and/or repairment may be more troublesome.

Thus, the inventors of the present invention surprisingly found that the above problems with the wear-resistant bars or another kind of disc-protectors on the outside periphery of the disc may be overcome by a disc according to the present invention,

A preferred embodiment of the present invention relates to a disc comprising a first flange and a second flange, wherein the first flange is placed parallel to, or substantially parallel to, the second flange and wherein an outer periphery of the first flange and/or to an outer periphery of the second flange are not provided with a wearing ring. In an embodiment of the present invention wherein a bracket may be attached directly to an outer periphery of the first flange and/or to an outer periphery of the second flange.

The wearing ring may be an annular element provided at the periphery of the disc (in the periphery of the first flange and in the periphery of the second flange) in order to increase the wear resistance of the disc and to provide a suitable and strong coupling between the bracket and the disc.

The inventors of the present invention surprisingly found that when welding the first and the second flange together at the outer end, and preferably at the outer end close to the periphery of the disc, providing at least one first welding, the metal in this area may act because of the heat of the welding and becomes harder and stronger and the wear resistance showed to increase.

Preferably, the first welding comprises a coherent welding and the first welding may be in contact with the first flange and the second flange.

In an embodiment of the present invention the first welding extends from an outer periphery of the first flange and/or from an outer periphery of the second flange and at least 5 mm towards an inner periphery of the first flange and/or towards an inner periphery of the second flange, such as at 7 mm, e.g. at least 10 mm, such as at 12 mm, e.g. at least 15 mm, such as at 17 mm, e.g. at least 20 mm, such as at 22 mm, e.g. at least 25 mm, such as in the range of 5-25 mm, e.g. in the range of 7-22 mm, such as in the range of 10-20 mm, e.g. in the range of 12-17 mm, such as about 15 mm.

This means that by increasing the extend or size of first weldings at the outer end of the first flange and the outer end of the second flange, or by increasing the effect of the first weldings, it may be possible to improve the strength, hardness and resistance of the outer end of the disc and the outer periphery of the disc.

Preferably, an outer end of the first flange may be parallel to, or substantially parallel to, an outer end of the second flange.

In an embodiment of the present invention the term "substantially parallel" may relate to an angle between the first flange and the second flange, in particular an angle of the outer end of the first flange and the outer end of the second flange, which is less than 6°, such as less than 5°, e.g. less than 4°, such as less than 3°, e.g. less than 2°, such as less than 1° . The first flange and/or the second flange may preferably comprise an outer periphery and an inner periphery.

The first flange and/or the second flange may preferably comprise an outer end and an inner end.

The inner end of the first flange and/or the second flange may be the end of the flanges (and the end of the disc) towards the centre of the flanges and/or the disc, and/or towards the rotor of a disc dryer.

The inner periphery of the disc according to the present invention may form a central hole of the disc. The inner end of the first flange and the inner end of the second flange extends from a central hole to the outer periphery of the disc.

When the disc according to the present invention may be welded to the hollow shaft of the rotor, welding stress may be generated between the disc and the hollow shaft, and the welding stress may cause the hollow shaft to bend, resulting in cracks appearing at the weld between the hollow shaft and the disc. These cracks may affect the performance of the disc and thus the dryer during operation. To reduce or even eliminate this welding stress the inner ends of the first flange and the second flange may be set in an arc shape form, and the ends arc-shaped form (the inner periphery may be fixed on the hollow shaft. In this way the welding stress may be eliminated and the service life of the dryer may be significantly improved.

In an embodiment of the present invention the inner end, or part of the inner end of the first flange and/or the second end may be provided in an arc shaped form (10).

The outer end of the first and/or second flange may constitute the parallel portions of the first flange and/or the second flange.

The inner end of the first and/or second flange may constitute the ach shaped form of the first flange and/or the arc shaped form of the second flange.

By setting the inner ends, or a part of the inner ends, of the first flange and/or the second flange into an arc shaped form, the stress on the plates during welding may be reduced significantly or even be eliminated, when welding with the rotor comprising a hollow shaft. Furthermore, the service life of the disc dryer can be improved. In an embodiment of the present invention the arc shaped form of the inner end of the first flange and/or the arc shaped form of the inner end of the second flange, may have a radius (curve radius) in the range of 30-75 mm, such as in the range of 40-70 mm, e.g. in the range of 50-65 mm, such as in the range of 53-60 mm, e.g. about 55 mm.

The radius (the curve radius) may preferably be determined as the outside radius (outside curve radius) relative to the interior of the disc.

In an embodiment of the present invention the arc shaped form may be provided within the first 200 mm from an inner periphery of the disc (on the first flange and/or second flange), such as within 100 mm, e.g. within 50 mm, such as within 40 mm, e.g. within 30 mm.

It may be advantageous to begin the arc shaped form closely to the inner periphery because it would improve the space available for welding the discs to the hollow shaft of the rotor. Preferably, the arc shaped form may be provided directly from the inner periphery.

In an embodiment of the present invention wherein a cavity may be provided in the space between the first flange and the second flange.

The cavity of the disc of the present invention may be closed at the outer end of the disc.

The outer end of the disc may preferably be the outer end of the first flange and the outer end of the second flange.

The inner end of the disc may preferably be the inner end of the first flange and the inner end of the second flange.

In an embodiment of the present invention the outer periphery of the disc may be the outer periphery of the first flange and the outer periphery of the second flange.

In a further embodiment of the present invention the inner periphery of the disc may be the inner periphery of the first flange and the inner periphery of the second flange.

The first flange and the second flange may be equal in lengths. Preferably, the outer end of the first flange is aligned with the outer end of the second flange. The alignment of the outer end of the first flange with the outer end of the second flange may be determined relative to the perpendicular direction of the parallel portion of the disc (or the parallel portion of the first flange or second flange).

In an embodiment of the present invention the outer end of the first flange and the outer end of the second flange may be combined by a first welding.

The combination of the outer end of the first flange and the outer end of the second flange may fuse the outer end of the first flange and the outer end of the second flange together by the first welding.

The size of the first welding (to increase the extend from an outer periphery of the first flange and/or to an outer periphery of the second flange and towards an inner periphery of the first flange and/or to an inner periphery of the second flange) may be applied by one layer or string of welding material or as multiple layers or strings of welding materials. Preferably, multiple layers or strings of welding materials may include two or more layers or strings of welding materials may be applied such as 3 or more, e.g. 4 or more, such as 5 or more, e.g. 6 or more, such as 7 or more.

Preferably, the multiple layers or strings of the welding materials may preferably be placed adjacent to each other. Preferably, the multiple layers or strings of welding materials are welded together in continuation of each other.

In a further embodiment of the present invention, the first weldings may form one coherent first welding comprising multiple layers or strings.

Preferably, the part of the first welding placed closest to the outer periphery of the disc may align with, or substantially align with, the outer periphery of the first flange and the outer periphery of the second flange.

In an embodiment of the present invention the disc may comprise an inner periphery and an outer periphery, wherein the outer periphery comprises a diameter (determined from the centre point of the disc) which is at least 1,5 times a diameter of the inner periphery, such as at least 2 times the diameter, e.g. at least 2.5 times the diameter, such as at least 3 times the diameter.

In a further embodiment of the present invention the disc may comprise an inner periphery and an outer periphery, wherein outer periphery comprises a diameter (determined from the centre point of the disc) which is in the range of 1.2-4 times a diameter of the inner periphery, such as in the range of 1.5-3 times the diameter of the inner periphery, e.g. in the range of 1.75-2.5 times the diameter of the inner periphery, such as in the range of 1.9-2.2 times the diameter of the inner periphery.

The inventors of the present invention surprisingly found that to allow proper fixation of the bracket to the outer periphery of the disc, the first welding may not extend to much out from the outer periphery of the disc, as there may be a risk that the brackets subsequently mounted on the outer periphery of the disc, may become unstably mounted to the outer periphery of the disc.

In an embodiment of the present invention the part of the first welding placed closest to the outer periphery of the disc may be provided as a continuous connection between the first flange and the second flange.

In the contest of the present invention the term "substantially aligns with" may relate to minor irregularities or deviations.

Without being bound by theory, the inventors of the present invention trust that by increasing the temperature and by controlling the temperature of the outer end of the first bland and the outer end of the second flange the metal in these areas may become harder and stronger and the wear resistance may increase to such an extent that it is unnecessary to add a wear resistance plate or wear resistance ring at the outer periphery of the disc to provide a high wear resistance of the disc.

In an embodiment of the present invention the outer end of the disc may comprise a wear improved part and a heating part.

The wear improved part of the outer end of the disc may be the part of the outer end of the disc closest to the periphery of the disc covering the area where the first weldings are made.

In an embodiment of the present invention the wear improved part of the disc may comprise an increased strength and/or an increased hardness compared to the heating part of the disc.

The heating part of the outer end may comprise the cavity between the outer end of the first flange and the outer end of the second flange.

The cavity of the disc may preferably be suitable for allowing steam to move in order to heating the disc for the specific drying purpose. The flanges of the discs according to the present invention may be held together by stay bolts. Stay bolts may be made by welding welding holes on both sides of the disc (both in the first flange and in the second flange). Increased numbers of stay bolts and welding points may increase the strength of each welding and of the disc as such. Furthermore, the flanges and the disc may become stronger, results in a more rigid construction, and prolongs the production time for providing the rotor.

On the other hand, increasing the numbers of welding points and stay bolts may result in a cavity formation (opening) of the disc, or deformation of the disc (or the flanges of the disc), due to the heat distortion during welding.

In an embodiment of the present invention the stay bolts may be placed along one or more circular distances from the central hole.

The circular distances may be defined as the distance from the centre point of the disc to a row of stay bolts.

The centre point may be the centre of the centrale hole.

In an embodiment of the present invention the stay bolts may be placed in two or more rows of stay bolts at a circular distance from the centre point, such as in three or more rows of stay bolts at a circular distance from the centre point, e.g. in four or more rows of stay bolts at a circular distance from the centre point. Preferably, the stay bolts may be placed in three rows of stay bolts having the same, or substantially the same, circular distance from the centre point.

The row of stay bolts may include a number of stay bolts having the same distance from the centre point of the disc, and preferably evenly distributed over the surface of the flanges of the disc.

The numbers of circular distances (or rows of stay bolts) from the centre point of the disc may depend on the size of the disc. The larger the disc the more circular distances (and rows of stay bolts) may be relevant.

The circular distance may be the radius from the centre point to a rows of stay bolts, resulting in a group of stay bolts having the same, or substantially the same, distance to the centre point. The disc according to the present invention may be provided with a multiplicity of stay bolts wherein the multiplicity of stay bolts between the first flange and the second flange.

The disc according to the present invention comprises a multiplicity of stay bolts which are placed in one or more rows; preferably in two or more rows; more preferably, in three or more rows, along one or more circular distances from the centre point.

Preferably, the disc according to the present invention is provided with a homogenous distribution of stay bolts, or a substantially homogenous distribution of stay bolts.

The first flange and the second flange of the disc according to the present invention may be providing a stay bolt pattern and with an area per stay bolt in the range of 100-350 cm² per stay bolt.

By providing the disc according to the present invention, the inventors surprisingly found that it is possible to provide discs with limited or no cavity formation, easier to produce, having straighter flanges, more homogenous, easier to align and weld on the rotor, with improved wear allowance when used e.g. in a disc dryer.

The inventors of the present invention also found that by increasing the number of stays bolts in the disc, or in the first flange and in the second flange, it was possible to increase the wear allowance, the corresponding corrosion allowance, significantly. Therefore, the homogenous distribution of stay bolts and the number of stay bolts in the disc may be important and to avoid the distance between the stay bolts to be too large (with the risk of making the disc weak and instable with the risk of deformation) and at the same time avoiding the distance between the stay bolts to be too short (with the risk of deformation of the disc due to heat distortion).

In an embodiment of the present invention the distance between individual stay bolts or between the stay bolts and the outer periphery, or the stays and the inner periphery may be in the range of 100-160 mm, such as in the range of 110-150 mm, e.g. in the range of 120-140 mm, such as in the range of 125-135 mm.

The distance between the two or more rows of stay bolts, such as the distance between the three or more rows of stay bolts, may be in the range of 200-350 mm, such as in the range of 225-325 mm or more, e.g. in the range of 250-300 mm. In an embodiment of the present invention the area between 3 stay bolts may be defined by a circle having a diameter in the range of 100-160 mm, such as in the range of 110- 150 mm, e.g. in the range of 120-140 mm, such as in the range of 125-135 mm.

The circle defining the area between 3 stay bolts may be in touch with the periphery of 3 stay bolts.

If the rows of stay bolts may be aligned to a radial distance from the centre point a similar circle defining the area may be made between 4 stay bolts instead of 3 stay bolts. In an embodiment of the present invention the circle defining the area may be made between 4 stay bolts may have a diameter in the range of 100-160 mm, such as in the range of 110- 150 mm, e.g. in the range of 120-140 mm, such as in the range of 125-135 mm.

In a further embodiment of the present invention the area between 2 stays and the outer periphery may be defined by circle having a diameter in the range of 100-160 mm, such as in the range of 110-150 mm, e.g. in the range of 120-140 mm, such as in the range of 125-135 mm.

In a further embodiment of the present invention the area between 2 stays and the inner periphery may be defined by circle having a diameter in the range of 100-160 mm, such as in the range of 110-150 mm, e.g. in the range of 120-140 mm, such as in the range of 125-135 mm.

When providing a disc according to the present invention there may be a relatively well- defined distance between individual stay bolts of the disc, since too few stay bolts in the disc may cause an insufficient assembling of the first flange and the second flange in constructing the disc resulting in e.g. weak, in-stable and/or deformed disc with insufficient strength.

On the other hand, when too many stay bolts may be introduced the amount of work in preparing the disc may be too extensive and too expensive and may cause the first flange and/or the second flange to deform due to the excessive amount of heat provided (heat distortion. Furthermore, increased tension may be imposed on the first flange and the second flange from all the stay bolts introduced, resulting in undesired openings at the intersection of the first flange and the second flange and impaired application.

In an embodiment of the present invention the construction of the disc may be defined by the area per stay bolt. Preferably, the disc may be provided with in the range of 100-350 cm² per stay bolt, e.g. in the range of 120-325 cm² per stay bolt, such as in the range of 130-300 cm² per stay bolt, e.g. in the range of 140-275 cm² per stay bolt, such as in the range of 150-250 cm² per stay bolt, e.g. in the range of 160-225 cm² per stay bolt, such as in the range of 170-220 cm² per stay bolt, e.g. in the range of 180-210 cm² per stay bolt, such as about 200 cm² per stay bolt.

The term "area per stay bolt" may provide a value or a determination of the number of stay bolts necessary to provide a disc having optimal strength relative to the reduced risk of deformation and unintentional openings along the intersection of the outer end of the first flange and the outer end of the second flange.

Preferably, the disc may be provided with a multiplicity of stay bolts wherein the multiplicity of stay bolts are provided with a homogenous distribution of stay bolts, or a substantially homogenous distribution of stay bolts, providing a stay bolt pattern and with an area per stay bolt in the range of 100-350 cm² per stay bolt, e.g. in the range of 120- 325 cm² per stay bolt, such as in the range of 130-300 cm² per stay bolt, e.g. in the range of 140-275 cm² per stay bolt, such as in the range of 150-250 cm² per stay bolt, e.g. in the range of 160-225 cm² per stay bolt, such as in the range of 170-220 cm² per stay bolt, e.g. in the range of 180-210 cm² per stay bolt, such as about 200 cm² per stay bolt.

The homogenous distribution of stay bolts, or a substantially homogenous distribution of stay bolts, may relate to a uniform and/or consistent distribution of stay bolts a multiplicity of stay bolts in the first flange and the second flange.

This homogenous distribution of stay bolts, or a substantially homogenous distribution of stay bolts, may make alignment of the welding holes in the first flange and the second flange easier when inserting the stay bolts.

The stay bolt may be provided in a welding hole. The welding hole may comprise an angled boarder. The angled boarder may improve the strength, formation and/or the durability of the welding/the stay bolt.

In an embodiment of the present invention the angled boarder may have an angle relative to a perpendicular cut into the first flange or into the second flange which is in the range of 15-45°, such as in the range of 20-40°, such as in the range of 25-35°, e.g. about 30° . Preferably, the angle is determined from the inside of the disk to the outside of the disk.

In the context of the present invention the welding may be performed by welding and/or soldering. In an embodiment of the present invention the outer end of the disc comprises a wear improved part (12) and a heating part (13) and wherein the wear improved part of the disc comprises an increased strength and/or an increased hardness compared to the heating part of the disc.

In an embodiment of the present invention the disc according to the present invention may preferably comprise an annular body.

The annular body may comprise and inner periphery and an outer periphery. The inner periphery of the disc according to the present invention may be attached to a rotor comprising a hollow shaft.

The disc according to the present invention may be provided with one or more brackets, such as two or more brackets, e.g. three or more brackets, such as 4 or more brackets, e.g. 5 or more brackets, such as 6 or more brackets, e.g. 7 or more brackets, such as 8 or more brackets, e.g. 9 or more brackets, such as 10 or more brackets, e.g. 12 or more brackets, such as 14 or more brackets, e.g. 16 or more brackets, such as 18 or more brackets, e.g. 20 or more brackets.

The one or more brackets may be provided at the outer periphery of the disc. The one or more brackets may be in contact with the outer periphery of the first flange and/or the outer periphery of the second flange and/or the first welding combining the first flange and the second flange, preferably the first welding combining the first flange and the second flange and placed closest to the outer periphery of the disc.

The one or more brackets may be attached to the outer periphery of the disc (e.g. to the outer periphery of the first flange and/or the outer periphery of the second flange) by providing a second welding.

Preferably, the second welding may be covering the periphery, or part of the periphery, of the first flange and/or the second flange, and a lower end of the one or more brackets.

The lower end of the one or more brackets may be a portion of the one or more brackets being about 0.1-15% of the hight of the bracket, such as about 0.3-10%, e.g. at least 0.5- 5%, such as at least 0.75-2.5%, e.g. at least 1-2%.

The one or more brackets may extend in a radial direction from the outer periphery of the disc, in particular from the outer periphery of the first flange and/or the outer periphery of the second flange. The second welding may be extending (in radial direction) by a distance in the range of 1- 20 mm, such in the range of 2-15 mm, e.g. in the range of 4-12 mm, such in the range of 6-10 mm, e.g. in the range of 7-9 mm, such as about 8 mm.

When the disc may be provided with two or more brackets, the two or more brackets attached to the outer periphery of the disc may preferably be evenly distributed along the outer periphery of the disc.

In an embodiment of the present invention the disc comprises 4 brackets attached to the outer periphery of the disc and the 4 brackets are evenly distributed by an angular distance of 90 degrees.

A preferred embodiment of the present invention relates to a bracket for a disc (preferably a bracket for a disc for a disc dryer) comprising a base part and a couplings part, wherein a base-length of the base part is larger than a coupling-length of the coupling part.

The base-length may be determined at the surface of the base part facing away from the coupling part, preferably in the longitudinal direction of the length of the bracket.

The coupling length at the point for coupling the paddles, preferably at the fixing means for attaching paddles to the one or more brackets, preferably, in the longitudinal direction of the length of the bracket.

Preferably, the base-length of the base part may be at least 10% larger than the couplinglength of the coupling part, e.g. at least 20% larger, such as at least 30% larger, e.g. at least 40% larger, such as at least 50% larger, e.g. at least 60% larger, such as at least 70% larger, e.g. at least 80% larger, such as at least 90% larger, e.g. at least 100% larger, such as at least 125% larger, e.g. in the range of 10-125% larger, such as in the range of 20-100%, e.g. in the range of 30-80% larger, such as in the range of 40-70%, e.g. in the range of 45-60% larger, such as in the range of 47-55%.

The bracket may comprise a flat and preferably rigid body. The bracket may comprise a hight and/or length that is significantly larger than the width. In an embodiment of the present invention the hight and the length (at the longest part of the bracket) is at least 2 times the width, such as at least 3 times the width, e.g. at least 4 times the width, such as at least 5 times the width, e.g. at least 6 times the width, such as at least 7 times the width, e.g. at least 8 times the width, such as at least 9 times the width, e.g. at least 10 times the width such as at least 11 times the width, e.g. at least 12 times the width, such as at least 15 times the width, e.g. at least 20 times the width, e.g. in the range of 2-20 times the width, such as in the range of 3-15 times the width, e.g. in the range of 5-12 times the width, such as in the range of 7-11 times the width, e.g. about 10 times the width.

In an embodiment of the present invention the bracket may comprise a length (at the longest part of the bracket) which is the same or larger than the hight of the bracket, in particular the bracket has a length which may be at least 10% larger than the hight, e.g. at least 20% larger, such as at least 30% larger, e.g. at least 40% larger, such as at least 50% larger, e.g. at least 60% larger, such as at least 70% larger, e.g. at least 80% larger, such as at least 90% larger, e.g. at least 100% larger, such as at least 125% larger, e.g. in the range of 10-125% larger, such as in the range of 20-100%, e.g. in the range of 25- 75% larger, such as in the range of 30-50%, e.g. in the range of 33-45% larger, such as in the range of 36-42%.

Preferably, the bracket may be of uniform thickness.

In an embodiment of the present invention the base part and the coupling part may be connected by at least one inclining side.

The base part and the coupling part may be connected by at least one inclining side, preferably the base part and the coupling part are connected by two inclining sides. The at least one inclining side(s) are inclining from the end of (or from both the ends of) the base part to the end of (or to both the ends of) the coupling part.

The inclination of the side between the base part and the coupling part of the bracket may be provided to avoid product during use in e.g. a disc dryer, to build up and accumulate at the base of the bracket and to increase the wear resistance of the disc.

The increased length of the base part of the bracket may allow improved strength when welded (a second welding) to the outer periphery of the first flange and/or to an outer periphery of the second flange.

Furthermore, the increased length of the base part of the bracket relative to the coupling part, and/or the effect of the at least one inclining sides, may result in an easier instalment, substitution and/or replacement of paddles to the brackets.

The inclination of the side between the base part and the coupling part of the bracket may be provided with an angle relative to the longitudinal direction of the length of the bracket, in the range of 10-80°, such as in the range of 20-70°, e.g. in the range of 30-60°, such as in the range of 40-50°, e.g. about 45° .

The inclination of the side between the base part and the coupling part of the bracket may form a protrusion relative to the coupling part of the bracket, in the longitudinal direction of the length of the bracket.

An embodiment of the present invention relates to a bracket for a disc (for a disc dryer) comprising a plate material, the plate material comprises a base part and a couplings part, wherein bracket comprises at least one, preferably two, protrusion(s) in the base part relative to the coupling part of the bracket (preferably, in the longitudinal direction of the length of the bracket).

In an embodiment of the present invention the bracket may be provided with rounded corners of the coupling part.

Preferably, the base part may be spherically shaped. This spherically shape may improve the fit with the outer periphery of the first flange and/or to an outer periphery of the second flange. In particular, a base-surface of the base part of the bracket, facing away from the couplings part, may be spherically shaped.

In order to improve the second welding between the bracket and the first flange and/or the outer periphery of the second flange, the base part may be provided with two or more legs pointing from the base part and away from the bracket.

The at least two legs may be between 1-20 mm, such as in the range of 2-15 mm, e.g. in the range of 3-10 mm, such as in the range of 4-7 mm, e.g. about 5 mm.

In an embodiment of the present invention, the base part of the bracket may be provided with at least 2 legs.

Preferably, the bracket comprising the base part and the coupling part, may be provided in one piece of material. Preferably, the bracket is provided in metal, in particular, the bracket may be provided in stainless steel.

The one or more brackets may comprise one or more fixing means. The fixing means may be suitable for attaching paddles to the one or more brackets and to the disc according to the present invention. Preferably, the bracket may comprise 2 fixing means, such as 3 fixing means, e.g. 4 fixing means, such as 5 fixing means, e.g. 6 fixing means. Most preferably the bracket comprises 2 fixing means since one fixing mean may be insufficient to keep a stable and steady positioning of the attached paddle, and more than 2 fixing means may be unnecessary.

The paddles may be provided to agitate and move the material to be dried and optionally to move the material to be dried towards a discharge outlet of the disc dryer.

In an embodiment of the present invention the material used for the first flange of the disc and/or for the second flange of the disc may comprise a metal material. Preferably the metal material may comprise stainless steel. Preferably, the stainless steel may be selected from DIN 1.4301 stainless steel; DIN 1.4401 stainless steel; DIN 1.4404 stainless steel; DIN 1.4541 stainless steel; or DIN 1.0425 stainless steel.

A preferred embodiment of the present invention relates to a rotor comprising a hollow shaft and at least one disc according to the present invention.

A preferred embodiment of the present invention relates to a disc dryer comprising a rotor according to the present invention or a disc according to the present invention.

The disc according to the present invention may be welded to the hollow shaft of the rotor by a manual welding process or by an automatic welding process, or a combination of a manual process and an automatic welding process.

The disc according to the present invention may be welded to the hollow shaft of the rotor,

The disc according to the present invention may be a hollow disc or a partly hollow disc, where the outer end of the disc (comprising the outer end of the first flange and the outer end of the second flange) comprise the first welding and closes the outer end of the disc.

The central hole may have a diameter which may be adapted to the outer circumference of the hollow shaft of a rotor on which the disc, or a multiplicity of discs may be mounted.

The hollow disc may comprise a central hole fitted for receiving a rotor.

The outer circumference of the central hole of the present invention may be defined the inner periphery of the disc. In an embodiment of the present invention the central hole may have a diameter which is larger than the diameter (outside diameter) of the hollow shaft of the rotor on which the disc may be mounted.

The central hole may have a diameter which may be larger, but less than 10% larger than the diameter (outside diameter) of the hollow shaft of the rotor on which the disc may be mounted, such as less than 7.5% larger, e.g. less than 5% larger, such as less than 2.5% larger, e.g. less than 1% larger, e.g. less than 0.5% larger.

A preferred embodiment of the present invention the hollow shaft of the rotor may have a distance between: a) the inner end of the first flange/or the inner end of the second flange of a first disc; and b) the inner end of the first flange /or the inner end of the second flange of a second (or further) disc; in the range of 45-75 mm, such as in the range of 50-70 mm, e.g. in the range of 52-69 mm, such as in the range of 54-68 mm, e.g. in the range of 56-67 mm, such as in the range of 58-65 mm, e.g. in the range of 60-64 mm, such as about 62 mm.

In an embodiment of the present invention the wear allowance of a disc according to the present invention, when used in a disc dryer, may preferably be higher than 4.0 mm, such as higher than 4.25, e.g. higher than 4.5, such as higher than 4.75, e.g. higher than 5.0, such as higher than 5.25, e.g. higher than 5.5.

In an embodiment of the present invention the wear allowance of a disc according to the present invention, when the disk is used in a disc dryer, may preferably be in the range of 4.0-6.0 mm, such as in the range of 4.50-5.75, e.g. in the range of 4.75-5.50, such as in the range of 5.00-5.50.

The disc dryer according to the present invention may be used for drying sludge, fat, slaughterhouse offal, rendering products like blood meal, bone meal, feathers meal, fish meal, plant materials (like soya and canola).

A preferred embodiment of the present invention relates to a dryer comprising a disc or a multiplicity of discs according to the present invention or a rotor according to the present invention.

Even the present invention describes a dryer comprising the discs according to the present invention, a hollow shaft according to the present invention, or a rotor according to the present invention, it must be pointed out that such discs according to the invention can also be used in any heat exchanger, i.e. also for general heating and cooling of a material.

It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention.

The invention will now be described in further details in the following non-limiting detailed description of the figures.

References

(1): Disc

(2): First flange

(3): Second flange

(4): Bracket

(5a): Outer periphery of the first flange

(5b): Outer periphery of the second flange

(6a): Inner periphery of the first flange

(6b): Inner periphery of the second flange

(7a): Outer end of the first flange

(7b): Outer end of the second flange

(8a): Inner end of the first flange

(8b): Inner end of the second flange

(9): Rotor

(10a): Arc shaped form of the first flange

(10b): Arc shaped form of the second flange

(11): Cavity

(12): Wear improved part

(13): Heating part

(14): First welding (the entire first welding)

(14a): The part of the first welding closest to the outer periphery

(15): Fixing means (on the brackets)

(16): Wearing ring

(17): Disc dryer

(18): Stay bolt

(19): Second welding

(20): Base part of the bracket

(21): Coupling part of the bracket

(22): Inclining side of the bracket

(23): Legs of the bracket

(24): Protrusions of the bracket

(25): Rounded corners of the bracket

(26): Base surface of the bracket

(LI): Base-length of the bracket

(L2): Coupling-length of the bracket

Claims

1. A disc (1) comprising a first flange (2) and a second flange (3), wherein at least part of the first flange (2) is placed in parallel to, or substantially in parallel to, at least part of the second flange (3) and wherein a first welding (14) is provided between the first flange (2) and the second flange (3) and the first welding (14) extends from an outer periphery of the first flange (5a) and an outer periphery of the second flange (5b) and at least 5 mm and towards an inner periphery of the first flange (6a) and an inner periphery of the second flange (6b).

2. The disc (1) according to anyone of the preceding claims wherein a bracket (4) is attached directly to an outer periphery of the first flange (5a) and/or to an outer periphery of the second flange (5b).

3. The disc (1) according to anyone of the preceding claims, wherein the outer periphery of the first flange (5a) and/or the outer periphery of the second flange (5b) are not provided with a wearing ring.

4. The disc (1) according to anyone of the preceding claims, wherein a part of the first welding (14a) placed closest to the outer periphery of the disc aligns with, or substantially aligns with, the outer periphery of the first flange (5a) and/or to an outer periphery of the second flange (5b).

5. The disc (1) according to anyone of the preceding claims, wherein the first welding (14) placed closest to the outer periphery of the disc is provided as a continuous connection between the first flange and the second flange.

6. A disc (1) comprising a first flange (2) and a second flange (3), wherein the first flange (2) is placed parallel to, or substantially parallel to, the second flange (3) and wherein an outer periphery of the first flange (5a) and/or to an outer periphery of the second flange (5b) are not provided with a wearing ring.

7. The disc (1) according to claim 6, wherein a bracket is attached directly to an outer periphery of the first flange (5a) and/or to an outer periphery of the second flange (5b).

8. A bracket (4) for a disc (for a disc dryer) comprising a base part (20) and a couplings part (21), wherein a base-length (LI) of the base part (20) is larger than a coupling-length (L2) of the coupling part (21).

9. The bracket according to claim 8, wherein the base part (20) and the coupling part (21) are connected by at least one inclining side (22).

10. The bracket according to anyone of claims 8-9, wherein the base part of the bracket is provided with at least 2 legs (23).

11. A disc comprising a bracket according to anyone of claims 8-10.

12. A rotor (9) comprising a hollow shaft and at least one disc (1) according to anyone of claims 1-7 or 11.

13. A disc dryer comprising a rotor according to claim 12.