WO2023089020A1 - Disc for a disc dryer - Google Patents

Disc for a disc dryer Download PDF

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Publication number
WO2023089020A1
WO2023089020A1 PCT/EP2022/082259 EP2022082259W WO2023089020A1 WO 2023089020 A1 WO2023089020 A1 WO 2023089020A1 EP 2022082259 W EP2022082259 W EP 2022082259W WO 2023089020 A1 WO2023089020 A1 WO 2023089020A1
Authority
WO
WIPO (PCT)
Prior art keywords
flange
disc
range
stay
stay bolts
Prior art date
Application number
PCT/EP2022/082259
Other languages
French (fr)
Inventor
Per Bonne ERIKSEN
Tristan Tarp NIELSEN
Original Assignee
Haarslev Industries A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Haarslev Industries A/S filed Critical Haarslev Industries A/S
Publication of WO2023089020A1 publication Critical patent/WO2023089020A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B23/00—Heating arrangements
    • F26B23/10—Heating arrangements using tubes or passages containing heated fluids, e.g. acting as radiative elements; Closed-loop systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
    • F26B25/04—Agitating, stirring, or scraping devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/18—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact
    • F26B3/22—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact the heat source and the materials or objects to be dried being in relative motion, e.g. of vibration
    • F26B3/24—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact the heat source and the materials or objects to be dried being in relative motion, e.g. of vibration the movement being rotation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B9/00—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards
    • F26B9/06—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards in stationary drums or chambers
    • F26B9/08—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards in stationary drums or chambers including agitating devices, e.g. pneumatic recirculation arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B2200/00—Drying processes and machines for solid materials characterised by the specific requirements of the drying good
    • F26B2200/18—Sludges, e.g. sewage, waste, industrial processes, cooling towers

Definitions

  • the present invention relates to a disc for a disc dryer and a disc dryer as such.
  • 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.
  • disc dryer including several discs built around a rotor comprising of a central 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 removes the evaporated water vapor.
  • 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.
  • the drying method of a disc dryer is based on the heat exchange between the product's contact with the discs, which are heated by e.g. hot liquid or steam circulation in the interior of the discs.
  • an efficient purge system may eliminate the condensate inside the shaft, ensuring maximum yield.
  • disc driers demonstrating good properties in relation to drying of wet materials.
  • the characteristics of such a disc drier are that it consists of a stationary chamber, and that a rotor is arranged inside this chamber, with a number of hollow discs welded perpendicularly onto the central rotor tube.
  • the discs a traditionally having a triangular cross-section with the wide part attached to the rotor and the tip pointing away from the rotor. It is preferred to place the discs as close as possible to provide the largest area for drying as possible.
  • the hot fluid medium or the steam flows through 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) evaporates as the material comes into contact with the hot surfaces of the discs.
  • the large surface provided by the disc dryers may be responsible for the effective heat exchange and the effective drying capacity.
  • the shape of the disc plates can vary and several types are described.
  • the most common construction of the disc dryers comprises a series of hollow discs secured to the rotor, mainly by welding.
  • the discs consist of two plates stuck together with a number of stay bolts (stay bolts) welded in the two plates. These stay bolts provide strength to the discs and keep the plates together when pressure is put on the hot fluid or the steam inside the discs.
  • disc construction relates to a disc comprising a solid circular shaped plate, onto which is welded a number of vertical steel plates, onto each of which is welded a flat piece of steel so that the whole construction can be characterised as a ring armature on which the opposite plate segments are placed and welded on.
  • the constructions of the discs can be described as two plane plates are used in each individual disc, and stay bolts, which penetrate the plates, are provided (preferably by welding) to hold the plates tightly together and to reduce leakage of the discs from the interior to the exterior of hot fluid or steam.
  • the effectivity of the disc dryer lies, for one thing, in increased surface area provided in the disc dryer, therefore there is an interest in the industry to increase the number of discs on the rotor to increase the surface area.
  • the problem with this would be the working area when welding the discs to the rotor as the distance between the discs are very limited both during the initial construction and during replacement and repair.
  • the effectivity of the dryer may be affected by the formation of cavities/openings in the discs. This often happens during welding of the disc to the rotor and may be caused by heat distortion from the welding.
  • the heat from the welding also show to affect the homogenous and smooth construction of the discs which may also affect effectivity and productivity.
  • an improved disc and rotor for a disc dryer 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 to manufacture, improved productivity, higher wear resistance, improved stress level would be advantageous.
  • an object of the present invention relates to a disc for a disc dryer, and a disc dryer as such.
  • an aspect of the present invention relates to a disc (1) comprising a first flange (3) and a second flange (4), wherein a first end (5) of the first flange (3) and a first end (6) of the second flange (4) extends from a central hole (16) of the disc (1) and wherein a second end (7) of the first flange (3) and a second end (8) of the second flange (4) are combined in a tip (9), wherein the disc is 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 cm 2 per stay bolt.
  • the tip (9) may be provided by the intersection (11) of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°- 7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° ; and/or
  • the first flange (3) and the second flange (4) comprise a multiplicity of stay bolts (12) wherein the multiplicity of stay bolts (12) a provided with a substantially homogenous distribution providing a stay bolt pattern.
  • Another aspect of the present invention relates to a rotor comprising two or more discs according to the present invention.
  • Yet another aspect of the present invention is to provide a dryer comprising one or more discs according to the present invention or a rotor according to the present invention.
  • Still another aspect of the present invention is to provide a heat exchanger comprising one or more discs according to the present invention or a rotor according to the present invention.
  • Figure 1 shows a front view of a disc according to the present invention
  • Figure 2 shows a side view of the disc according to the present invention looking from the cross-section A-A from figure 1,
  • Figure 3 shows two views of the area B illustrating the concave structure of the disc and the first and second flanges
  • Figure 4 shows a multiplicity of discs according to the present invention built around a rotor provided as a central shaft.
  • the rotor may be enclosed into a closed a series of hollow discs secured to the rotor, mainly by welding.
  • the discs consist of two plates stuck together with a number of stay bolts (stay bolts) welded in the two plates.
  • 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.
  • the Disc Dryers are 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 by means of steam through a heavy central rotor. This rotor has a special innovative design without intermediate distance bolts.
  • Disc Dryers are pure contact dryers, heated by steam.
  • the dryer is premanufactured in workshop and has a small footprint comparing to convection dryers.
  • the product will be mechanically conveyed through the dryer, which minimizes the demand for electrical energy.
  • the double-walled discs are sitting on a central tube which are heated by steam from the inside.
  • the product is continuously circulated in the rotating disk bundle, and shovels fixed at the circumference transport the product axially through the disc bundle dryers.
  • Scrapers that are fixed between the discs ensure thorough mixing of the product and also prevent product from sticking to the discs. Indirect heating allows a gentle and environmentally friendly drying process.
  • a preferred embodiment of the present invention relates to a disc comprising a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the disc is 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 cm 2 per stay bolt.
  • a further preferred embodiment of the present invention relates to a disc comprising a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein:
  • the tip may be provided by the intersection of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°-7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° ; and/or
  • the first flange and the second flange comprise a multiplicity of stay bolts wherein the multiplicity of stay bolts a provided with a substantially homogenous distribution providing a stay bolt pattern.
  • 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.
  • the term “extends from a central hole” relates to the starting point of first flange and the second flange defining the disc surface and defining the central hole.
  • the first flange (in particular a first end of the first flange) and the second flange (in particular a first end of the second flange) extends from a central hole, in particular from the outer periphery of the central hole.
  • the disc according to the present invention may comprise a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the first end or the first flange and/or the first end of the second flange are provided with a concave structure.
  • the concave structure may relate to a curving structure in or hollowed inward towards the inside of the disc.
  • the concave structure of the first end of the first flange may be concave in the direction towards the second flange.
  • the concave structure of first end of the second flange may be concave in the direction towards the first flange.
  • the concave structure of the first end of the first flange and/or the first end of the second flange may be provided as a circular element.
  • the concave structure of the first end of the first flange and/or the concave structure of the first end of the second flange, or the circular element 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.
  • the outside radius may be defined as the outside radius following the outside surface of the disc and the concave structure.
  • the concave structure of the first end of the first flange and/or the concave structure of the first end of the second flange, or the circular element may have an inside radius (inside curve radius) in the range of 40-85 mm, such as in the range of 50-75 mm, e.g. in the range of 60-70 mm, such as about 65 mm.
  • the inside radius may preferably be determined as the inside radius relative to the interior of the disc.
  • the inside radius may be defined as the inside radius of the inside part of the disc, in particular the hollow disk, and the inside part of the concave structure.
  • the concave structure may be provided within the first 200 mm from an inside rim 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 concave structure closely to the inside rim because it would improve the space available for welding the discs to the rotor. Preferably, the concave structure may be provided directly from the inside rim.
  • the concave structure may be provided in a distance from 5-200 mm from an inside rim of the disc, such as in a distance from 10-100 mm, e.g. 15-50 mm, such as in a distance from 20-45 mm, e.g. 30-40 mm.
  • the disc may comprise a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the tip may be provided by the intersection of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°-7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° .
  • the angle (a) may be provided the intersection or the contact of the second end of the first flange and the second end of the second flange.
  • section may relate to the abutment of the second end of the first flange and the second end of the second flange, such as the point where the second end of the first flange and the second end of the second flange meet.
  • the first flange and/or the second flange may comprise a concave structure followed by a straight part, or a substantially straight part, between the first end, preferably comprising the concave structure, and the second end comprising the tip, where the first flange and the second flange may be in direct contact.
  • the second end of the first flange, the second end of the second flange, and the tip may form part of the straight part.
  • the tip of the disc may be provided by bending or folding a plate material.
  • the tip may be formed in the bend/fold and the first flange may be one of the sides of the tip and the second flange may be the other side of the tip.
  • the tip of the disc may be provided by welding the second end of the first flange together with the second end of the second flange.
  • the plate material according to the present invention may comprise a metal material.
  • the metal material may comprise stainless steel.
  • the stainless steel is 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.
  • the disc according to the present invention disc may comprise a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the first flange and the second flange comprise a multiplicity of stay bolts wherein the multiplicity of stay bolts a provided with a substantially homogenous distribution providing a stay bolt pattern.
  • the flange of the discs according to the present invention may be held together by stay bolts.
  • Stay bolts may be made by welding prefabricated 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.
  • 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 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.
  • the row of stay bolts may be 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 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 comprises a multiplicity of stay bolts which are placed in one or more rows along one or more circular distances from the centre point.
  • the disc (or the first flange and the second flange) comprises one row of stay bolts. In another embodiment of the present invention the disc (or the first flange and the second flange) comprises two rows of stay bolts. In yet an embodiment of the present invention the disc (or the first flange and the second flange) comprises three rows of stay bolts. In an even further embodiment of the present invention the disc (or the first flange and the second flange) comprises four rows of stay bolts.
  • the stay bolts are placed in two or in three, preferably three, rows of stay bolts.
  • the stay bolts are placed in two or in three, preferably three, rows of stay bolts, and wherein the distance from the outermost row of stay bolts to the outside rim is smaller than the distance from the innermost row of stay bolts to the inside rim.
  • the inventors of the present invention found that a homogenous distribution of stay bolts in the surface of the disc provide an increased strength to the disc and a higher wear allowance
  • the distance between the stay bolts in the row of stay bolts provided closest to the inside rim are smaller than the distance between the stay bolts in the row of stays provided closest to the outside rim.
  • the number of stay bolts may be the same in all the rows of stay bolts provided in the disc or in the first and the second flanges.
  • the inventors of the present invention also found that by increasing the number of stays 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).
  • the distance between individual stay bolts or between the stay bolts and the outside rim, or the stays and the inside rim are 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 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.
  • 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.
  • a similar circle defining the area may be made between 4 stay bolts instead of 3 stay bolts.
  • 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.
  • the area between 2 stays and the outside rim 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.
  • the area between 2 stays and the inside rim 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.
  • the diameter of the circle defining the area between 2 stays and the inside rim may be smaller than the diameter of the circle defining the area between 2 stays and the inside rim.
  • 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.
  • 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.
  • the construction of the disc may be defined by the area per stay bolt.
  • the disc may be provided with in the range of 100-350 cm 2 per stay bolt, e.g. in the range of 120-325 cm 2 per stay bolt, such as in the range of 130-300 cm 2 per stay bolt, e.g. in the range of 140-275 cm 2 per stay bolt, such as in the range of 150-250 cm 2 per stay bolt, e.g. in the range of 160-225 cm 2 per stay bolt, such as in the range of 170-220 cm 2 per stay bolt, e.g. in the range of 180-210 cm 2 per stay bolt, such as about 200 cm 2 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 second end of the first flange and the second end of the second flange.
  • 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 cm 2 per stay bolt, e.g. in the range of 120- 325 cm 2 per stay bolt, such as in the range of 130-300 cm 2 per stay bolt, e.g.
  • the 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 may make alignment of the welding holes in the first flange and the second flange easier when inserting the stay bolts.
  • the first flange (in particular a first end of the first flange) and the second flange (in particular a first end of the second flange) extends from a central hole, in particular from the outer periphery of the central hole.
  • the extension of the first flange and the second flange may constitute an inside rim of the disc. Furthermore, the inside rim may be formed by the first flange (resulting in a first inside rim) and/or by the second flange (resulting in a second inside rim).
  • the tip of the disc may form an outer periphery of the disc.
  • the outer periphery of the disc may constitute an outside rim of the disc.
  • the disc may comprise an inside rim and an outside rim, wherein the outside rim comprises a diameter (determined from the centre point of the disc) which is at least 1,5 times a diameter of the inside rim, 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.
  • the disc may comprise an inside rim and an outside rim, wherein outside rim 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 inside rim, such as in the range of 1.5-3 times the diameter of the inside rim, e.g. in the range of 1.75-2.5 times the diameter of the inside rim, such as in the range of 1.9-2.2 times the diameter of the inside rim.
  • the inside rim may preferably be circular shaped.
  • the outside rim may preferably be circular shaped.
  • the peripheral speed of the disk, when rotating may be larger at the outer peripheral side (e.g. the outside rim of the disc) than on the inner peripheral side of the disk (e.g. the inside rim of the disc), resulting in a rapidly increased wear of the disk at the outer peripheral edge portion of the disk, and this outer peripheral side (outside rim of the disc) may be become increasingly worn resulting in the risk of leakage of heat medium, such as steam, from the disc, and it may be necessary to repair the disk or the disk may be discarded, even though the portion other than the outer peripheral edge portion of the disk can be sufficiently used.
  • the outer peripheral side e.g. the outside rim of the disc
  • the inner peripheral side of the disk e.g. the inside rim of the disc
  • Solutions in the prior at may deal with this increased wear of the outside rim by supplying e.g. a wear- resista nt bar or another kind of disc-protector which are welded on the outside rim of the disk to increase wear resistance.
  • the challenge with adding wear- resista nt bars or another kind of disc- protectors to the outside rim 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, and/or repairment may be more troublesome.
  • 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 rim of the disc may be overcome by the disc according to the present invention, where the outside rim of the second end of the first flange may be extending further from the intersection between the second end of the first flange and the second end of the second flange.
  • This, new construction of the disc may improve the wear resistance of the disc reduce the formation of cavities/openings in the disc, allow higher stress and increased working pressure in the disc.
  • the outside rim of the second end of the second flange may end in the intersection between the second end of the first flange and the second end of the second flange.
  • the disc according to the present invention comprises an outside rim of the second end of the first flange which may be extending further from the intersection between the second end of the first flange and the second end of the second flange than an outside rim of the second end of the second flange.
  • the outside rim of the disc may not be provided with a wear-resistant bar or another kind of disc-protector which may be welded on the outside rim of the disk (to increase wear resistance).
  • the disc according to the present invention comprising a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein
  • the tip may be provided by the intersection of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°-7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° ; and
  • the first flange and the second flange comprise a multiplicity of stay bolts wherein the multiplicity of stay bolts a provided with a substantially homogenous distribution providing a stay bolt pattern.
  • the stay bolt pattern of the disc may comprise an area per stay bolt in the range of 100- 350 cm 2 per stay bolt, e.g. in the range of 120-325 cm 2 per stay bolt, such as in the range of 130-300 cm 2 per stay bolt, e.g. in the range of 140-275 cm 2 per stay bolt, such as in the range of 150-250 cm 2 per stay bolt, e.g. in the range of 160-225 cm 2 per stay bolt, such as in the range of 170-220 cm 2 per stay bolt, e.g. in the range of 180-210 cm 2 per stay bolt, such as about 200 cm 2 per stay bolt
  • the first flange and the second flange may be provided with multiple welding holes.
  • the welding holes of the first flange are organised opposite to the welding holes of the second flange.
  • the welding holes may be evenly distributed over the surface of the disc.
  • a welding may be provided in the welding hole of the first flange and/or in the welding hole of the second flange providing a stay bolt in the hole between the first flange and the second flange.
  • 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.
  • 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° .
  • the angle is determined from the inside of the disk to the outside of the disk.
  • the welding may be performed by welding and/or soldering.
  • the disc according to the present invention may preferably be a disc for a disc dryer.
  • a disc dryer When used in a disc dryer, multiple discs are stacked along a rotor where the discs are welded to each other, to the rotor or to both.
  • the disc may be a hollow disc.
  • the hollow part of the disc may be surrounded by a first flange and a second flange.
  • the hollow disc comprises an opening from the central hole into a cave formed by the first flange and the second flange.
  • the first end of the first flange and the first end of the second flange may be spaced apart.
  • a distance (L) between the first end of the first flange and a first end of the second flange may be at least 10 mm, such as at least 25 mm, e.g. at least 50 mm, such as at least 75 mm, e.g. at least 100 mm, such as at least 125 mm, e.g. at least 140 mm, such as about 144 mm.
  • the central hole may be a circular hole.
  • the central hole may have a diameter which may be adapted to 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 central hole of the present invention may be defined the inside rim.
  • the central hole may have a diameter which is larger than the diameter (outside diameter) of the rotor on which the disc is to 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 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.
  • the rotor may have a distance between: a) the first end of the first flange/or the first end of the second flange of one disc; and b) the first end of the first flange /or the first 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.
  • the distance between: a) the first end of the first flange/or the first end of the second flange of one disc; and b) the first end of the first flange /or the first end of the second flange of a second (or further) disc; may be increased by at least 10% relative to the conventional rotor comprising two or more discs, such as at least 15%, e.g. at least 20%, such as at least 25%, e.g. at least 30%.
  • the distance between the flange of one disc to the next disc may be measured close to the rotor, preferably immediately after the concave structure.
  • the cavity formation of the disk may be a result of heat where the flanges twists and may create an open space into the disk at, or around, the inside rim of the disk and a rotor.
  • the cavity formation of the disk is less than 12 mm, such as less than 10 mm, e.g. less than 8 mm, such as less than 6 mm, e.g. less than 4 mm, such as less than 2 mm, e.g. no cavity formation.
  • the wear allowance 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.
  • the wear allowance 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, and fish meal.
  • 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.
  • the present invention describes a dryer comprising the discs 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.
  • Figure 1 shows front view of a disc (1) according to the present invention comprising one of two flanges (3/4) the other flange is on the back side of the view in figure 1 and demonstrates together a first flange (3) a second flange (4).
  • the flanges comprise a first end the flange (5/6 - depending on whether the flange is the first flange (3) or the second flange (4)) extending from a central hole (16), in particular extending from the outer periphery of the central hole (16) of the disc (1).
  • the extension of the flange (3/4) from the outer periphery of the central hole (16) may constitute an inside rim of the disc (14).
  • the flange extends from the inside rim (14) to the outside end of the disc, the outside rim (15) where the first flange (3) and the second flange (4) are combined in a tip (9).
  • the outside rim (15a) of the second end of the first flange (3) may be extending further from the intersection between the second end of the first flange and the second end of the second flange than the outside rim (15b) of the second end of the second flange (4).
  • the flanges (3/4) are provided with a multiplicity of stay bolts (12) wherein the multiplicity of stay bolts (12) a provided with a substantially homogenous distribution providing a stay pattern.
  • the stay bolt pattern in figure 1 comprises a multiplicity of stay bolts (12) which are placed in three rows along three circular distances from the centre point (C).
  • the distance from the outermost row (13a) of stay bolts (12) to the outside rim (15) may be smaller than the distance from the innermost row (13b) of stay bolts (12) to the inside rim (14).
  • the homogenous distribution of stay bolts (12) in the surface (17) of the disc (1) provide an increased strength to the disc (1) and a higher wear allowance.
  • the number of stay bolts (12) may be the same in all the rows of stay bolts (12) provided in the disc (1) or in the first and the second flanges (3/4). In figure 1, 38 stay bolts (12) in each row of the disc (1) and the distance between the individual stay bolts (12) in each row are smaller the closer one comes to the centre point (C) and the inside rim of the disc (14).
  • Figure 2 shows the cross sectional side view of the disc (1) as shown in figure 1.
  • Figure 2 shows a disc (1) according to the present invention comprising a first flange (3) and a second flange (4).
  • Each of the flanges (3/4) comprises a first end (5/6) extending from an outside rim (14) of the disc (1).
  • the first end (5) of the first flange (3) and the first end (6) of the second flange (4) may be separated by a distance (L).
  • the outside rim (14) may also represent the periphery of the central hole (16) of the disk (1).
  • a second end of the flanges (7/8) are combined in a tip (9) which may be formed by the intersection (11) of the first flange (3) and the second flange (4) and may form an outside rim (15) of the disc (1).
  • the outside rim (15a) of the second end of the first flange (3) may be extending further from the intersection between the second end of the first flange and the second end of the second flange than the outside rim (15b) of the second end of the second flange (4).
  • the first end (5) or the first flange (3) and the first end (6) of the second flange (4) are provided with a concave structure (10) and the concave structures (10) are provided with a radius of 55 mm resulting in 10-20% more space at the first end of the flanges when welding several discs (1) on the rotor (not shown).
  • the first flange (3) and the second flange (4) are held together by a multiplicity of stay bolts (12) which are homogenously distributed over the surface of the disc (1).
  • FIG 3 shows a close-up of a subsection of the disc (1) according to the present invention a first flange (3) and a second flange (4).
  • Each of the flanges (3/4) comprises a first end (5/6) extending from an outside rim (14) of the disc (1).
  • the first end (5) of the first flange (3) and the first end (6) of the second flange (4) may be separated by a distance (L).
  • the outside rim (14) may also represent the periphery of the central hole (16) of the disk (1).
  • a second end of the flanges (7/8) are combined in a tip (9) which may be formed by the intersection (11) of the first flange (3) and the second flange (4) and may form an outside rim (15) of the disc (1).
  • the outside rim (15a) of the second end of the first flange (3) may be extending further from the intersection between the second end of the first flange and the second end of the second flange than the outside rim (15b) of the second end of the second flange (4).
  • the first end (5) or the first flange (3) and the first end (6) of the second flange (4) are provided with a concave structure (10) and the concave structures (10) are provided with a radius of 55 mm resulting in 10-20% more space at the first end of the flanges when welding several discs (1) on the rotor (not shown).
  • the first flange (3) and the second flange (4) are held together by a multiplicity of stay bolts (12) which are homogenously distributed over the surface of the disc (1).
  • the first flange (3) and the second flange (4) are provided with a concave structure (10) followed by a straight part, or a substantially straight part, between the first end (5/6), preferably comprising the concave structure (10), and the second end (7/8) comprising the tip (9).
  • the second end (7) of the first flange (3), the second end (8) of the second flange (4), and the tip (9) forms part of the straight part.
  • Figure 4 shows a rotor (2) having a multiplicity of discs (1) according to the present invention mounted.
  • the discs (1) comprise a first flange (3) and the second flange (not visible) having a concave structure (10).
  • the disc comprises an inside rim (14) and an outside rim (15) and a surface (17), which surface (17) comprises a multiplicity of stay bolts (12).
  • the discs (1) are hollow and the rotor (2) is hollow, and when the discs (1) a welded on the rotor (2) drying media (e.g. steam or liquid) the media may flow through the rotor (2) and into the discs (1). Examples
  • a traditional type disc (i) and a disc according to the present invention (ii).
  • Both discs had an outside diameter of 2200 mm and an inside diameter of 1100 mm (the diameter of the central hole of the disc).
  • the discs prepared were hollow and the wall thickness was 10 mm.
  • the distance between the inside rim of the first flange and the inside rim of the second flange are the same, 137 mm.
  • the first (i) disc (the conventional one) comprises an area per stay bolt of 375 cm 2 /stay bolt, and the disc was provided with two rows of stay bolts, each row comprising 38 stay bolts (in total 76 stay bolts in the disc), where the first row of stay bolts was located in a circular distance of 1500 mm from the centre point (C) having a distance between the individual stay bolts of about 175 mm and the second row of stay bolts was located in a circular distance of 1800 mm from the centre point (C) having a distance between the individual stay bolts of about 157 mm.
  • the first and second flanges of the disc were constructed as a straight flange from the inside rim to the tip of the disc, the resulting angle of the tip of the disk is 7.8° .
  • the first disc comprises an outside rim of the second end of the first flange which is extending further from the intersection between the second end of the first flange and the second end of the second flange than an outside rim of the second end of the second flange. 64 first discs are welded to the rotor and it is ready to be tested.
  • the second (ii) disc (the disc according to the present invention) comprises an area per stay bolt of 250 cm 2 /stay bolt, and the disc was provided with three rows of stay bolts, each row comprising 38 stay bolts (in total 114 stay bolts in the disc), where the first row of stay bolts was located in a circular distance of 1400 mm from the centre point (C); the second row of stay bolts was located in a circular distance of 1650 mm from the centre point (C); and the third row of stay bolts was located in a circular distance of 1950 mm from the centre point (C).
  • the distance between the individual stay bolts in the second disc are about 130 mm.
  • the construction of the second disc also comprises a concave structure having a radius of 55 mm from the inside rim (14) of the disc from the concave structure the first flange and the second flange continued as straight flanges to the tip of the disc, resulting in an angle of the tip of 6.3° .
  • the first disc comprises an outside rim of the second end of the first flange which is extending further from the intersection between the second end of the first flange and the second end of the second flange than an outside rim of the second end of the second flange.64 first discs are welded to the rotor and it is ready to be tested.
  • the wear allowance was significantly increased from 3.8 mm to 5.19 mm.
  • the discs prepared according to the present invention also showed to be straighter and more homogenous disc design compared to the conventionally prepared discs and resulting in improved welding of the discs.
  • the test of the new discs show that improved performance and productivity may be provided by the new design of the discs by increased wear resistance reduced cavity formation (openings) and higher stress and higher working pressure. It also showed that the new design of the disc allowed improved construction of the disc dryer an improved welding of the discs to the rotor because the additional space between the discs.

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Abstract

The present invention relates to a disc comprising a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the disc is 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.

Description

DISC FOR A DISC DRYER
Technical field of the invention
The present invention relates to a disc for a disc dryer and a disc dryer as such.
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 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 removes the evaporated water vapor.
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 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's contact with the discs, which are heated by e.g. hot liquid or steam circulation in the interior of the discs. When using steam, an efficient purge system may eliminate the condensate inside the shaft, 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. 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 is arranged inside this chamber, with a number of hollow discs welded perpendicularly onto the central rotor tube. The discs a traditionally having a triangular cross-section with the wide part attached to the rotor and the tip pointing away from the rotor. It is preferred to place the discs as close as possible to provide the largest area for drying as possible.
During operation, the hot fluid medium or the steam flows through 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) evaporates as the material comes 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.
The shape of the disc plates can vary and several types are described.
The most common construction of the disc dryers comprises a series of hollow discs secured to the rotor, mainly by welding. The discs consist of two plates stuck together with a number of stay bolts (stay bolts) welded in the two plates. These stay bolts provide strength to the discs and keep the plates together when pressure is put on the hot fluid or the steam inside the discs.
Another variation of disc construction relates to a disc comprising a solid circular shaped plate, onto which is welded a number of vertical steel plates, onto each of which is welded a flat piece of steel so that the whole construction can be characterised as a ring armature on which the opposite plate segments are placed and welded on.
The constructions of the discs can be described as two plane plates are used in each individual disc, and stay bolts, which penetrate the plates, are provided (preferably by welding) to hold the plates tightly together and to reduce leakage of the discs from the interior to the exterior of hot fluid or steam.
As mentioned above the effectivity of the disc dryer lies, for one thing, in increased surface area provided in the disc dryer, therefore there is an interest in the industry to increase the number of discs on the rotor to increase the surface area. The problem with this would be the working area when welding the discs to the rotor as the distance between the discs are very limited both during the initial construction and during replacement and repair. Furthermore, the effectivity of the dryer may be affected by the formation of cavities/openings in the discs. This often happens during welding of the disc to the rotor and may be caused by heat distortion from the welding.
The heat from the welding also show to affect the homogenous and smooth construction of the discs which may also affect effectivity and productivity.
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 to manufacture, improved productivity, higher wear resistance, improved stress level would be advantageous.
Summary of the invention
Thus, an object of the present invention relates to a disc for a disc dryer, and a disc dryer as such.
In particular, it is an object of the present invention to provide a disc that solves the above-mentioned problems of the prior art with accessibility or space between the discs when attached to the rotor, wear allowance, cavity formation (openings), heat distortion from welding, uniformity of individual discs and between the discs.
Thus, an aspect of the present invention relates to a disc (1) comprising a first flange (3) and a second flange (4), wherein a first end (5) of the first flange (3) and a first end (6) of the second flange (4) extends from a central hole (16) of the disc (1) and wherein a second end (7) of the first flange (3) and a second end (8) of the second flange (4) are combined in a tip (9), wherein the disc is 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.
Another aspect of the invention relates to a disc (1) comprising a first flange (3) and a second flange (4), wherein a first end (5) of the first flange (3) and a first end (6) of the second flange (4) extends from a central hole (16) of the disc (1) and wherein a second end (7) of the first flange (3) and a second end (8) of the second flange (4) are combined in a tip (9), wherein:
(i) the first end (5) or the first flange (3) and/or the first end (6) of the second flange (4) are provided with a concave structure (10);
(ii) the tip (9) may be provided by the intersection (11) of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°- 7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° ; and/or
(iii) the first flange (3) and the second flange (4) comprise a multiplicity of stay bolts (12) wherein the multiplicity of stay bolts (12) a provided with a substantially homogenous distribution providing a stay bolt pattern.
Another aspect of the present invention relates to a rotor comprising two or more discs according to the present invention.
Yet another aspect of the present invention is to provide a dryer comprising one or more discs according to the present invention or a rotor according to the present invention.
Still another aspect of the present invention is to provide a heat exchanger comprising one or more discs according to the present invention or a rotor according to the present invention.
Brief description of the figures
Figure 1 shows a front view of a disc according to the present invention,
Figure 2 shows a side view of the disc according to the present invention looking from the cross-section A-A from figure 1,
Figure 3 shows two views of the area B illustrating the concave structure of the disc and the first and second flanges, and
Figure 4 shows a multiplicity of discs according to the present invention built around a rotor provided as a central shaft. The rotor may be enclosed into a closed a series of hollow discs secured to the rotor, mainly by welding. The discs consist of two plates stuck together with a number of stay bolts (stay bolts) welded in the two plates.
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.
The Disc Dryers are 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 by means of steam through a heavy central rotor. This rotor has a special innovative design without intermediate distance bolts.
These Disc Dryers are pure contact dryers, heated by steam. The dryer is premanufactured in workshop and has a small footprint comparing to convection dryers. The product will be mechanically conveyed through the dryer, which minimizes the demand for electrical energy.
Inside the dryer the double-walled discs are sitting on a central tube which are heated by steam from the inside. The product is continuously circulated in the rotating disk bundle, and shovels fixed at the circumference transport the product axially through the disc bundle dryers. Scrapers that are fixed between the discs ensure thorough mixing of the product and also prevent product from sticking to the discs. Indirect heating allows a gentle and environmentally friendly drying process.
Thus, a preferred embodiment of the present invention relates to a disc comprising a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the disc is 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. A further preferred embodiment of the present invention relates to a disc comprising a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein:
(i) the first end or the first flange and/or the first end of the second flange are provided with a concave structure;
(ii) the tip may be provided by the intersection of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°-7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° ; and/or
(iii) the first flange and the second flange comprise a multiplicity of stay bolts wherein the multiplicity of stay bolts a provided with a substantially homogenous distribution providing a stay bolt pattern.
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.
In the context of the present invention, the term "extends from a central hole" relates to the starting point of first flange and the second flange defining the disc surface and defining the central hole.
In an embodiment of the present invention the first flange (in particular a first end of the first flange) and the second flange (in particular a first end of the second flange) extends from a central hole, in particular from the outer periphery of the central hole.
The disc according to the present invention may comprise a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the first end or the first flange and/or the first end of the second flange are provided with a concave structure.
The concave structure may relate to a curving structure in or hollowed inward towards the inside of the disc. In an embodiment of the present invention the concave structure of the first end of the first flange may be concave in the direction towards the second flange.
In a further embodiment of the present invention the concave structure of first end of the second flange may be concave in the direction towards the first flange.
The concave structure of the first end of the first flange and/or the first end of the second flange may be provided as a circular element.
In an embodiment of the present invention the concave structure of the first end of the first flange and/or the concave structure of the first end of the second flange, or the circular element 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.
The outside radius may be defined as the outside radius following the outside surface of the disc and the concave structure.
In an embodiment of the present invention the concave structure of the first end of the first flange and/or the concave structure of the first end of the second flange, or the circular element may have an inside radius (inside curve radius) in the range of 40-85 mm, such as in the range of 50-75 mm, e.g. in the range of 60-70 mm, such as about 65 mm.
The inside radius may preferably be determined as the inside radius relative to the interior of the disc.
The inside radius may be defined as the inside radius of the inside part of the disc, in particular the hollow disk, and the inside part of the concave structure.
In an embodiment of the present invention the concave structure may be provided within the first 200 mm from an inside rim 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 concave structure closely to the inside rim because it would improve the space available for welding the discs to the rotor. Preferably, the concave structure may be provided directly from the inside rim.
The concave structure may be provided in a distance from 5-200 mm from an inside rim of the disc, such as in a distance from 10-100 mm, e.g. 15-50 mm, such as in a distance from 20-45 mm, e.g. 30-40 mm.
In an embodiment of the present invention, the disc may comprise a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the tip may be provided by the intersection of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°-7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° .
The angle (a) may be provided the intersection or the contact of the second end of the first flange and the second end of the second flange.
In the context of the present invention the term "intersection" may relate to the abutment of the second end of the first flange and the second end of the second flange, such as the point where the second end of the first flange and the second end of the second flange meet.
The first flange and/or the second flange may comprise a concave structure followed by a straight part, or a substantially straight part, between the first end, preferably comprising the concave structure, and the second end comprising the tip, where the first flange and the second flange may be in direct contact.
In an embodiment of the present invention the second end of the first flange, the second end of the second flange, and the tip may form part of the straight part.
In an embodiment of the present invention the tip of the disc may be provided by bending or folding a plate material. The tip may be formed in the bend/fold and the first flange may be one of the sides of the tip and the second flange may be the other side of the tip.
In another embodiment of the present invention the tip of the disc may be provided by welding the second end of the first flange together with the second end of the second flange. The plate material according to the present invention may comprise a metal material. Preferably the metal material may comprise stainless steel. Preferably, the stainless steel is 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.
The disc according to the present invention disc may comprise a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein the first flange and the second flange comprise a multiplicity of stay bolts wherein the multiplicity of stay bolts a provided with a substantially homogenous distribution providing a stay bolt pattern.
The flange of the discs according to the present invention may be held together by stay bolts. Stay bolts may be made by welding prefabricated 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.
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.
The row of stay bolts may be 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 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.
Thus, the disc according to the present invention comprises a multiplicity of stay bolts which are placed in one or more rows along one or more circular distances from the centre point.
In an embodiment of the present invention the disc (or the first flange and the second flange) comprises one row of stay bolts. In another embodiment of the present invention the disc (or the first flange and the second flange) comprises two rows of stay bolts. In yet an embodiment of the present invention the disc (or the first flange and the second flange) comprises three rows of stay bolts. In an even further embodiment of the present invention the disc (or the first flange and the second flange) comprises four rows of stay bolts.
In yet an embodiment of the present invention the stay bolts are placed in two or in three, preferably three, rows of stay bolts.
In yet an embodiment of the present invention the stay bolts are placed in two or in three, preferably three, rows of stay bolts, and wherein the distance from the outermost row of stay bolts to the outside rim is smaller than the distance from the innermost row of stay bolts to the inside rim.
The inventors of the present invention found that a homogenous distribution of stay bolts in the surface of the disc provide an increased strength to the disc and a higher wear allowance
In an embodiment of the present invention the distance between the stay bolts in the row of stay bolts provided closest to the inside rim are smaller than the distance between the stay bolts in the row of stays provided closest to the outside rim.
In a further embodiment of the present invention the number of stay bolts may be the same in all the rows of stay bolts provided in the disc or in the first and the second flanges. Thus, by providing the disk according to the present invention, the inventors surprisingly found that it is possible to provide disks 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 in a disc dryer.
The inventors of the present invention also found that by increasing the number of stays 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 outside rim, or the stays and the inside rim are 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 are 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 outside rim 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 inside rim 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.
Preferably the diameter of the circle defining the area between 2 stays and the inside rim may be smaller than the diameter of the circle defining the area between 2 stays and the inside rim.
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 second end of the first flange and the second 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.
In an embodiment of the present invention the first flange (in particular a first end of the first flange) and the second flange (in particular a first end of the second flange) extends from a central hole, in particular from the outer periphery of the central hole.
The extension of the first flange and the second flange (form the outer periphery of the central hole) may constitute an inside rim of the disc. Furthermore, the inside rim may be formed by the first flange (resulting in a first inside rim) and/or by the second flange (resulting in a second inside rim).
The tip of the disc may form an outer periphery of the disc. Preferably, the outer periphery of the disc may constitute an outside rim of the disc.
In an embodiment of the present invention the disc may comprise an inside rim and an outside rim, wherein the outside rim comprises a diameter (determined from the centre point of the disc) which is at least 1,5 times a diameter of the inside rim, 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 inside rim and an outside rim, wherein outside rim 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 inside rim, such as in the range of 1.5-3 times the diameter of the inside rim, e.g. in the range of 1.75-2.5 times the diameter of the inside rim, such as in the range of 1.9-2.2 times the diameter of the inside rim.
The inside rim may preferably be circular shaped.
The outside rim may preferably be circular shaped.
During use in e.g. a disc dryer, the peripheral speed of the disk, when rotating, may be larger at the outer peripheral side (e.g. the outside rim of the disc) than on the inner peripheral side of the disk (e.g. the inside rim of the disc), resulting in a rapidly increased wear of the disk at the outer peripheral edge portion of the disk, and this outer peripheral side (outside rim of the disc) may be become increasingly worn resulting in the risk of leakage of heat medium, such as steam, from the disc, and it may be necessary to repair the disk or the disk may be discarded, even though the portion other than the outer peripheral edge portion of the disk can be sufficiently used.
Solutions in the prior at may deal with this increased wear of the outside rim by supplying e.g. a wear- resista nt bar or another kind of disc-protector which are welded on the outside rim of the disk to increase wear resistance. The challenge with adding wear- resista nt bars or another kind of disc- protectors to the outside rim 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, 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 rim of the disc may be overcome by the disc according to the present invention, where the outside rim of the second end of the first flange may be extending further from the intersection between the second end of the first flange and the second end of the second flange.
This, new construction of the disc may improve the wear resistance of the disc reduce the formation of cavities/openings in the disc, allow higher stress and increased working pressure in the disc.
Preferably, the outside rim of the second end of the second flange may end in the intersection between the second end of the first flange and the second end of the second flange. In an embodiment of the present invention the disc according to the present invention comprises an outside rim of the second end of the first flange which may be extending further from the intersection between the second end of the first flange and the second end of the second flange than an outside rim of the second end of the second flange.
In an embodiment of the present invention the outside rim of the disc may not be provided with a wear-resistant bar or another kind of disc-protector which may be welded on the outside rim of the disk (to increase wear resistance).
In a preferred embodiment, the disc according to the present invention comprising a first flange and a second flange, wherein a first end of the first flange and a first end of the second flange extends from a central hole of the disc and wherein a second end of the first flange and a second end of the second flange are combined in a tip, wherein
(i) the first end or the first flange and/or the first end of the second flange are provided with a concave structure;
(ii) the tip may be provided by the intersection of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°-7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° ; and
(iii) the first flange and the second flange comprise a multiplicity of stay bolts wherein the multiplicity of stay bolts a provided with a substantially homogenous distribution providing a stay bolt pattern.
The stay bolt pattern of the disc may comprise 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
In an embodiment of the present invention the first flange and the second flange may be provided with multiple welding holes. Preferably the welding holes of the first flange are organised opposite to the welding holes of the second flange.
The welding holes may be evenly distributed over the surface of the disc. A welding may be provided in the welding hole of the first flange and/or in the welding hole of the second flange providing a stay bolt in the hole between the first flange and the second flange.
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.
The disc according to the present invention may preferably be a disc for a disc dryer. When used in a disc dryer, multiple discs are stacked along a rotor where the discs are welded to each other, to the rotor or to both.
In an embodiment of the present invention the disc may be a hollow disc.
Preferably, the hollow part of the disc may be surrounded by a first flange and a second flange. Preferably, the hollow disc comprises an opening from the central hole into a cave formed by the first flange and the second flange.
To provided the hollow formed disc according to the present invention, the first end of the first flange and the first end of the second flange may be spaced apart.
In an embodiment of the present invention a distance (L) between the first end of the first flange and a first end of the second flange may be at least 10 mm, such as at least 25 mm, e.g. at least 50 mm, such as at least 75 mm, e.g. at least 100 mm, such as at least 125 mm, e.g. at least 140 mm, such as about 144 mm.
In an embodiment of the present invention, the central hole may be a circular hole.
The central hole may have a diameter which may be adapted to 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 central hole of the present invention may be defined the inside rim.
In an embodiment of the present invention the central hole may have a diameter which is larger than the diameter (outside diameter) of the rotor on which the disc is to 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 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 rotor may have a distance between: a) the first end of the first flange/or the first end of the second flange of one disc; and b) the first end of the first flange /or the first 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 distance between: a) the first end of the first flange/or the first end of the second flange of one disc; and b) the first end of the first flange /or the first end of the second flange of a second (or further) disc; may be increased by at least 10% relative to the conventional rotor comprising two or more discs, such as at least 15%, e.g. at least 20%, such as at least 25%, e.g. at least 30%.
The distance between the flange of one disc to the next disc may be measured close to the rotor, preferably immediately after the concave structure.
The cavity formation of the disk may be a result of heat where the flanges twists and may create an open space into the disk at, or around, the inside rim of the disk and a rotor. In an embodiment of the present invention the cavity formation of the disk is less than 12 mm, such as less than 10 mm, e.g. less than 8 mm, such as less than 6 mm, e.g. less than 4 mm, such as less than 2 mm, e.g. no cavity formation.
In the other hand increasing the number of stays in the disc, or in the first flange and in the second flange, there is a risk the disc opens up, e.g. end close to the rotor, or gets deformed due to heat distortion.
In an embodiment of the present invention the wear allowance 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, 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, and fish meal.
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 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 examples. Detailed description of the figures
Figure 1 shows front view of a disc (1) according to the present invention comprising one of two flanges (3/4) the other flange is on the back side of the view in figure 1 and demonstrates together a first flange (3) a second flange (4). The flanges comprise a first end the flange (5/6 - depending on whether the flange is the first flange (3) or the second flange (4)) extending from a central hole (16), in particular extending from the outer periphery of the central hole (16) of the disc (1). The extension of the flange (3/4) from the outer periphery of the central hole (16) may constitute an inside rim of the disc (14).
The flange extends from the inside rim (14) to the outside end of the disc, the outside rim (15) where the first flange (3) and the second flange (4) are combined in a tip (9). The outside rim (15a) of the second end of the first flange (3) may be extending further from the intersection between the second end of the first flange and the second end of the second flange than the outside rim (15b) of the second end of the second flange (4). The flanges (3/4) are provided with a multiplicity of stay bolts (12) wherein the multiplicity of stay bolts (12) a provided with a substantially homogenous distribution providing a stay pattern. The stay bolt pattern in figure 1 comprises a multiplicity of stay bolts (12) which are placed in three rows along three circular distances from the centre point (C). The distance from the outermost row (13a) of stay bolts (12) to the outside rim (15) may be smaller than the distance from the innermost row (13b) of stay bolts (12) to the inside rim (14). The homogenous distribution of stay bolts (12) in the surface (17) of the disc (1) provide an increased strength to the disc (1) and a higher wear allowance. The number of stay bolts (12) may be the same in all the rows of stay bolts (12) provided in the disc (1) or in the first and the second flanges (3/4). In figure 1, 38 stay bolts (12) in each row of the disc (1) and the distance between the individual stay bolts (12) in each row are smaller the closer one comes to the centre point (C) and the inside rim of the disc (14).
Figure 2 shows the cross sectional side view of the disc (1) as shown in figure 1. Figure 2 shows a disc (1) according to the present invention comprising a first flange (3) and a second flange (4). Each of the flanges (3/4) comprises a first end (5/6) extending from an outside rim (14) of the disc (1). The first end (5) of the first flange (3) and the first end (6) of the second flange (4) may be separated by a distance (L). The outside rim (14) may also represent the periphery of the central hole (16) of the disk (1). A second end of the flanges (7/8) are combined in a tip (9) which may be formed by the intersection (11) of the first flange (3) and the second flange (4) and may form an outside rim (15) of the disc (1). The outside rim (15a) of the second end of the first flange (3) may be extending further from the intersection between the second end of the first flange and the second end of the second flange than the outside rim (15b) of the second end of the second flange (4). The first end (5) or the first flange (3) and the first end (6) of the second flange (4) are provided with a concave structure (10) and the concave structures (10) are provided with a radius of 55 mm resulting in 10-20% more space at the first end of the flanges when welding several discs (1) on the rotor (not shown). The first flange (3) and the second flange (4) are held together by a multiplicity of stay bolts (12) which are homogenously distributed over the surface of the disc (1).
Figure 3 shows a close-up of a subsection of the disc (1) according to the present invention a first flange (3) and a second flange (4). Each of the flanges (3/4) comprises a first end (5/6) extending from an outside rim (14) of the disc (1). The first end (5) of the first flange (3) and the first end (6) of the second flange (4) may be separated by a distance (L). The outside rim (14) may also represent the periphery of the central hole (16) of the disk (1). A second end of the flanges (7/8) are combined in a tip (9) which may be formed by the intersection (11) of the first flange (3) and the second flange (4) and may form an outside rim (15) of the disc (1). The outside rim (15a) of the second end of the first flange (3) may be extending further from the intersection between the second end of the first flange and the second end of the second flange than the outside rim (15b) of the second end of the second flange (4). The first end (5) or the first flange (3) and the first end (6) of the second flange (4) are provided with a concave structure (10) and the concave structures (10) are provided with a radius of 55 mm resulting in 10-20% more space at the first end of the flanges when welding several discs (1) on the rotor (not shown). The first flange (3) and the second flange (4) are held together by a multiplicity of stay bolts (12) which are homogenously distributed over the surface of the disc (1). The first flange (3) and the second flange (4) are provided with a concave structure (10) followed by a straight part, or a substantially straight part, between the first end (5/6), preferably comprising the concave structure (10), and the second end (7/8) comprising the tip (9). The second end (7) of the first flange (3), the second end (8) of the second flange (4), and the tip (9) forms part of the straight part.
Figure 4 shows a rotor (2) having a multiplicity of discs (1) according to the present invention mounted. The discs (1) comprise a first flange (3) and the second flange (not visible) having a concave structure (10). The disc comprises an inside rim (14) and an outside rim (15) and a surface (17), which surface (17) comprises a multiplicity of stay bolts (12). The discs (1) are hollow and the rotor (2) is hollow, and when the discs (1) a welded on the rotor (2) drying media (e.g. steam or liquid) the media may flow through the rotor (2) and into the discs (1). Examples
Example 1
Two types of discs were prepared. A traditional type disc (i) and a disc according to the present invention (ii).
Both discs had an outside diameter of 2200 mm and an inside diameter of 1100 mm (the diameter of the central hole of the disc). The discs prepared were hollow and the wall thickness was 10 mm. The distance between the inside rim of the first flange and the inside rim of the second flange are the same, 137 mm.
The conventional disc
The first (i) disc (the conventional one) comprises an area per stay bolt of 375 cm2/stay bolt, and the disc was provided with two rows of stay bolts, each row comprising 38 stay bolts (in total 76 stay bolts in the disc), where the first row of stay bolts was located in a circular distance of 1500 mm from the centre point (C) having a distance between the individual stay bolts of about 175 mm and the second row of stay bolts was located in a circular distance of 1800 mm from the centre point (C) having a distance between the individual stay bolts of about 157 mm. The first and second flanges of the disc were constructed as a straight flange from the inside rim to the tip of the disc, the resulting angle of the tip of the disk is 7.8° . The first disc comprises an outside rim of the second end of the first flange which is extending further from the intersection between the second end of the first flange and the second end of the second flange than an outside rim of the second end of the second flange. 64 first discs are welded to the rotor and it is ready to be tested.
The disc according to the present invention
The second (ii) disc (the disc according to the present invention) comprises an area per stay bolt of 250 cm2/stay bolt, and the disc was provided with three rows of stay bolts, each row comprising 38 stay bolts (in total 114 stay bolts in the disc), where the first row of stay bolts was located in a circular distance of 1400 mm from the centre point (C); the second row of stay bolts was located in a circular distance of 1650 mm from the centre point (C); and the third row of stay bolts was located in a circular distance of 1950 mm from the centre point (C). The distance between the individual stay bolts in the second disc are about 130 mm. The construction of the second disc also comprises a concave structure having a radius of 55 mm from the inside rim (14) of the disc from the concave structure the first flange and the second flange continued as straight flanges to the tip of the disc, resulting in an angle of the tip of 6.3° . The first disc comprises an outside rim of the second end of the first flange which is extending further from the intersection between the second end of the first flange and the second end of the second flange than an outside rim of the second end of the second flange.64 first discs are welded to the rotor and it is ready to be tested.
Results
From testing the two disc configurations (the conventional disc, and the disc according to the present invention) the results show that:
1. providing a concave structure having a radius of 55 mm from the inside rim resulted in a significant increase in the space available between the discs, about 20-50% increase, allowing a better welding of the disc to the rotor and the cavity formation (openings) of the discs due to heat distortion was reduced from 10-15 mm to 5-8 mm.
2. The wear allowance was significantly increased from 3.8 mm to 5.19 mm.
3. The discs prepared according to the present invention also showed to be straighter and more homogenous disc design compared to the conventionally prepared discs and resulting in improved welding of the discs.
It is believed that these surprising improvements to the discs provided according to the present invention are provided by the new construction presented herein.
Hence, the test of the new discs show that improved performance and productivity may be provided by the new design of the discs by increased wear resistance reduced cavity formation (openings) and higher stress and higher working pressure. It also showed that the new design of the disc allowed improved construction of the disc dryer an improved welding of the discs to the rotor because the additional space between the discs.
References
(1): a disc
(2): a rotor
(3): first flange
(4): second flange
(5): first end of the first flange
(6): first end of the second flange
(7): second end of the first flange
(8): second end of the second flange
(9): the tip
(10): concave structure
(11): intersection of the first flange and the second flange
(12): Stay bolts
(14): inside rim of the disc
(15): outside rim of the disc
(15a): outside rim of the second end of the first flange
(15b): outside rim of the second end of the second flange
(16): central hole of the disc
(17): surface of the disc
(L): distance between the first end of the first flange and a first end of the second flange
(C): centre point of the disc
(a): the tip angle

Claims

24 Claims
1. A disc (1) comprising a first flange (3) and a second flange (4), wherein a first end (5) of the first flange (3) and a first end (6) of the second flange (4) extends from a central hole (16) of the disc (1) and wherein a second end (7) of the first flange (3) and a second end (8) of the second flange (4) are combined in a tip (9), wherein the disc is 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.
2. The disc according to claim 1, wherein the area per stay bolt is about 150-250 cm2 per stay bolt.
3. The disc according to anyone of the preceding claims, wherein the first end (5) or the first flange (3) and/or the first end (6) of the second flange (4) are provided with a concave structure (10).
4. The disc according to anyone of the preceding claims, wherein the tip (9) may be provided by the intersection (11) of the first flange and the second flange has an angle (a) in the range of 4.5°-8.0°, e.g. in the range of 5°-7.5°, such as in the range of 5.5°- 7.0°, e.g. in the range of 6.0°- 6.5°, such as in the range of 6.1°- 6.4°, e.g. in the range of 6.2°- 6.3° ; and/or
5. The disc according to anyone of the preceding claims, wherein the disc comprises an outside rim of the second end of the first flange which may be extending further from the intersection between the second end of the first flange and the second end of the second flange than an outside rim of the second end of the second flange.
6. The disc (1) according to anyone of the preceding claims, wherein a distance (L) between the first end (5) of the first flange (3) and a first end (6) of the second flange (4) is at least 10 mm, such as at least 25 mm, e.g. at least 50 mm, such as at least 75 mm, e.g. at least 100 mm, such as at least 125 mm, e.g. at least 140 mm, such as about 144 mm.
7. The disc (1) according to anyone of the preceding claims, wherein the central hole (16) has a diameter which is adapted to a rotor (20) on which the disc (1) is to be mounted.
8. The disc (1) according to anyone of the preceding claims, wherein the concave structure is provided within the first 200 mm from an inside rim 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.
9. The disc (1) according to anyone of the preceding claims, wherein the disc (1) is a hollow disc.
10. The disc (1) according to anyone of the preceding claims, wherein the stay bolts (12) are placed in two or more rows of stay bolts at a circular distance from the centre point (C).
11. The disc (1) according to anyone of the preceding claims, wherein the stay bolts (12) are placed in three or more rows of stay bolts at a circular distance from the centre point
12. The disc according to anyone of the preceding claims, wherein the distance between individual stay bolts or between the stay bolts and the outside rim, or the stay bolts and the inside rim are 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.
13. The disc according to anyone of the preceding claims, wherein the number of stay bolts is the same in all the rows of stay bolts provided in the disc or in the first and the second flanges.
14. A rotor comprising two or more discs according to anyone of claims 1-13
15. A dryer comprising a disc according to anyone of claims 1-13 or a rotor according to claim 14.
PCT/EP2022/082259 2021-11-17 2022-11-17 Disc for a disc dryer WO2023089020A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKPA202101088 2021-11-17
DKPA202101088 2021-11-17

Publications (1)

Publication Number Publication Date
WO2023089020A1 true WO2023089020A1 (en) 2023-05-25

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WO (1) WO2023089020A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110007918U (en) * 2010-02-03 2011-08-10 장우기계 주식회사 Abrasion resistant device of Disk-drier
CN110074251A (en) * 2019-05-05 2019-08-02 迈安德集团有限公司 The production system of soy protein concentrate
CN113402147A (en) * 2021-07-15 2021-09-17 杭州江河机电装备工程有限公司 Split type disc sludge drying machine
KR102308986B1 (en) * 2020-11-20 2021-10-05 나민수 Disk with improved pin fixing part for disk type dryer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110007918U (en) * 2010-02-03 2011-08-10 장우기계 주식회사 Abrasion resistant device of Disk-drier
CN110074251A (en) * 2019-05-05 2019-08-02 迈安德集团有限公司 The production system of soy protein concentrate
KR102308986B1 (en) * 2020-11-20 2021-10-05 나민수 Disk with improved pin fixing part for disk type dryer
CN113402147A (en) * 2021-07-15 2021-09-17 杭州江河机电装备工程有限公司 Split type disc sludge drying machine

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