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EP0811141B1 - Method and apparatus for demoisturizing moist products - Google Patents

Method and apparatus for demoisturizing moist products Download PDF

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Publication number
EP0811141B1
EP0811141B1 EP96904365A EP96904365A EP0811141B1 EP 0811141 B1 EP0811141 B1 EP 0811141B1 EP 96904365 A EP96904365 A EP 96904365A EP 96904365 A EP96904365 A EP 96904365A EP 0811141 B1 EP0811141 B1 EP 0811141B1
Authority
EP
European Patent Office
Prior art keywords
products
demoisturizing
air streams
moisture
discharge openings
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
EP96904365A
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German (de)
French (fr)
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EP0811141A1 (en
Inventor
Stephanus Michael Marie Backus
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Backus Beheer BV
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Backus Beheer BV
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Publication of EP0811141A1 publication Critical patent/EP0811141A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/02—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts or elements attached to endless belts or chains propelling the materials over stationary surfaces
    • F26B17/04—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts or elements attached to endless belts or chains propelling the materials over stationary surfaces the belts being all horizontal or slightly inclined
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/02—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts or elements attached to endless belts or chains propelling the materials over stationary surfaces
    • F26B17/026—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts or elements attached to endless belts or chains propelling the materials over stationary surfaces the material being moved in-between belts which may be perforated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/10—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers
    • F26B17/106—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers the drying enclosure, e.g. its axis, being substantially straight and horizontal, e.g. pneumatic drum dryers; the drying enclosure consisting of multiple substantially straight and horizontal stretches
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/24—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by shooting or throwing the materials, e.g. after which the materials are subject to impact

Definitions

  • the invention relates to a method for mechanically demoisturizing relatively vulnerable products like vegetables, fruits etc. which have a relatively large surface area per unit volume, by imparting an irregular movement to the products and collecting and discharging the moisture that is released by the irregular movement of the products, the irregular movement being imparted to the products by transporting them through a plurality of successive air streams, directed under an angle to their direction of transport, and the moisture being released from the products by blocking the movement of the products in the air streams.
  • the present invention is directed specifically at the mechanical processing of relatively vulnerable products like vegetables, fruits etc. which have a relatively large surface area per unit volume, which may not be subjected to high temperatures during demoisturizing or "dewatering" thereof, like vegetables, fruits etc. and especially of products having a relatively large surface area per unit volume, like lettuce products.
  • these products may be mechanically demoisturized by imparting an irregular movement, e.g. shaking or vibrating the products on sieves.
  • the known method of demoisturizing by shaking or vibrating takes a relatively large amount of time, thus decreasing the efficiency of the mechanical processing, and requiring relatively large processing installations for achieving a sufficient throughput.
  • the shaking or vibrating on sieves may easily lead to damaging the generally vulnerable lettuce products.
  • the invention therefore has for its object to provide a method of the type described above, with which vulnerable products have a large surface area per unit volume, and which may not be subjected to high temperatures, can be efficiently demoisturized. According to the invention this is accomplished in that the products are mechanically moved through the air streams, the air streams being directed substantially perpendicular to their direction of transport and the released moisture is discharged by suction.
  • the invention also relates to an apparatus for demoisturizing moist products, comprising means for imparting an irregular movement to the products, means for collecting moisture released by the products and means for discharging the collected moisture, the means for irregularly moving the products comprising a plurality of discharge openings for generating air streams, means for transporting the products along the discharge openings, under an angle to the air streams, and means for blocking the movement of the products in the air streams, spaced above the discharge openings in the direction of the air streams.
  • Such an apparatus is also known from the above-identified prior art document EP-A-0 058 398, where it is used for demoisturizing plastic granulate.
  • Another known apparatus which is generally used in mechanical washing and demoisturizing lines for e.g. vegetables or fruit, comprises a vibrating or shaking sieve for irregularly moving the products to be demoisturizing or dried, on which the products are advanced through the apparatus, while at the same time the adhering moisture is shaken or vibrated off.
  • the transport capacity of such vibrating or shaking sieves is, however, relatively low, whereas furthermore the danger of damage to the products is considerable.
  • the invention therefore also has for its object to provide an improved apparatus of the type described above, which apparatus is characterized according to the invention in that the transport means are mechanical transport means directed substantially perpendicularly to the air streams, and the moisture collecting means comprise at least one suction opening.
  • An apparatus 1 for demoisturizing or "dewatering" moist products 2 (fig. 1) comprises means for irregularly moving the products 2, means for collecting moisture released by the products, and means for discharging the collected moisture (not shown).
  • the means for irregularly moving the products 2 comprise means for generating an air stream A that varies over time and for guiding this air stream along the products 2, as well as means 16 for transporting the products 2 along the air stream generating means in accordance with the arrow T, substantially perpendicular to the air stream A.
  • the means for generating an air stream A and for guiding it along the products 2 comprise a plurality of pressure fans or compressors 3, each of which is connected with its pressure side to a lower part 5 of an inner housing 4.
  • the lower part 5 comprises sloped walls 13 defining a diffuser part 10, which is further bordered by vertical walls 6 and a top wall 7 (fig. 2).
  • the top wall 7 of the lower casing 5 comprises crenelles 8, which are open at the top and thus form discharge openings 9. These discharge openings 9 extend over substantially the entire width of the transport means 16.
  • the discharge openings 9 are spaced in the direction of transport T, whereby the products 2 which are supplied by the transport means 16 will be led through an air stream A several times during transport through the apparatus 1.
  • the transport means 16 incidentally comprise an air permeable belt conveyer 17 which is moveable along the discharge openings 9. This belt conveyer 17 is guided over guide rolls 18-23, and driven by a motor 24.
  • the demoisturizing apparatus 2 further comprises means 27 spaced from the discharge openings 9 in the direction of the air stream A for blocking the upward movement of the products 2.
  • These blocking means 27 comprise a moisture absorbing, air permeable belt conveyer 28 guided along guide rolls 29-32, which may be moved with the lower belt conveyer 17 in the direction of the arrow M, and is driven by a motor 43.
  • Suction openings 33 are arranged behind the moisture absorbing conveyer 28 when seen in the direction of the air stream A, these openings in turn being connected to the means for generating the air stream A. Through these suction openings 33 the moisture that is absorbed in the belt conveyer 28 is drawn off, after which it condenses against the inside of an outer housing 44 surrounding the inner housing 4. The return air R is further led back to the fans or compressors 3.
  • the number of suction openings 33 substantially corresponds with the number of discharge openings 9.
  • the suction openings 33 and the discharge openings 9 incidentally are not arranged opposite each other, but are staggered in the direction of transport T. Also, the air velocity at the suction openings 33 need not be equal to the discharge velocity of the air over the openings 9.
  • the discharge velocity may for instance be selected twice as high as the suction velocity, by selecting a total area of the discharge openings 9 which is approximately half the total area of the suction openings.
  • a demoisturizing apparatus 1 which has proven to be useful in practice may have a discharge velocity in the order of 10 to 70 m/s, preferably 40 m/s, while the suction velocity is 5 to 35 m/s, preferably 20 m/s.
  • the lower casing 5 Between the crenelles 8 the lower casing 5 comprises separation walls 37, which are placed somewhat inwardly of the sidewalls 6 of the lower casing 5, and which divide the space between the crenelles 8 in receptor bins 35 located at the inside, and bypass ducts 14 having discharge openings 36 for cleaning bypass air BL at the outside.
  • This bypass air BL which is led from the lower casing 5 through openings 38 to the bypass duct 14, and is finally blown out through the openings 36 along the edge of the conveyer 17, serves to prevent the product from assembling along the edge of the conveyer 17 and thus being caught and smeared between the conveyer 17 and the fixed parts of the apparatus 1.
  • the demoisturizing apparatus 1 will usually be installed at the end of a cleaning line for the products 2, so that products leaving the apparatus 1 will generally not be cleaned any further.
  • the receptor bins 35 between the walls 37 also serve to receive products which may fall through the belt conveyer 17, and to prevent these parts of the products from being smeared between the belt conveyer 17 and the fixed parts of the apparatus 1. Furthermore, the bins 35 as a matter of course receive part of the moisture released by the products 2.
  • the belt conveyer may be led through a cleaning installation 25 in its return path, in which for instance a cleaning fluid is sprayed onto the belt by means of spray tubes 26. Cleaning by means of for instance air or UV radiation is also a possibility. It will further be clear that the upper belt conveyer 28 may be subjected to a similar cleaning operation.
  • the suction openings 33 are constructed in a similar manner as the discharge openings 9, and are also arranged in crenelles 34, which form part of the bottom wall of an upper part 41 of the inner housing 4.
  • the spaces between the crenelles 34 serve as receptor areas 40, while the walls 39 arranged between the crenelles 34 serve as guidance for the upper belt conveyer 28.
  • the suction openings do not extend over the full width of the upper conveyer 28.
  • the moist air drawn off by the suction openings 33 is collected in the upper part 41 of the housing and is led back from there through an opening 42 as return air to the fans or compressors 3, thus forming a closed loop system.
  • the moisture present in the return air condenses against the inside of the outer housing 44. It is of course also possible to construct the apparatus 1 as an open loop system, in which the air that is drawn off is dried and discharged, and the compressors 3 continuously suck in fresh air.
  • an opening 11 is arranged at both sides between the lower part 5 and the upper part 41, which opening is closed off during operation of the apparatus 1 by a door 12, for instance an upwardly and downwardly moveable sliding door.
  • a door 12 for instance an upwardly and downwardly moveable sliding door.
  • the inner housing 4 constituted by the lower part 5 and the upper part 41 is completely surrounded by an outer housing 44, which is formed by side walls 45, a bottom 54, a top 46 and front and rear walls 47, 48. Openings 49 are arranged in the front and rear walls 47, 48 for letting through the transport means 16 and moveable blocking means 27.
  • the outer housing 44 the moisture from the return air R, which mostly condenses against the walls of the housing, is collected and eventually discharged.
  • Both the guiding surfaces for the belt conveyers 17, 28 formed by the lower crenelles 8 and the upper crenelles 34 respectively, are arched. This curvature allows the belt conveyers 17 and 28, respectively to be properly tensioned, and thus the risk of the conveyers "floating" on the air stream A is minimized.
  • the apparatus 1 may further comprise mechanical means 50 for irregularly moving the belt conveyer 17 and the products 2 lying thereon.
  • These mechanical moving means 50 comprise a shaft 51, carrying two parallel, eccentric knocking members 52, which will lift the belt conveyer 17 somewhat during rotation of the shaft 51, after which the conveyer will regain its original shape as a result of the tension therein.
  • a considerable vibrating or shaking movement is imparted to the products.
  • the belt 17 is relatively light weight when compared to for instance a vibrating or shaking sieve, it can be subjected to fairly considerable accelerations perpendicularly to its plane; thus allowing an effective first separation of the moisture and products.
  • the moisture released during this first separation is directly collected in the outer housing 44.
  • the speed of each of these parts may be independently selected.
  • the blowing and suction force of the compressors 3 may also be separately selected.
  • the amount of moisture separation by the knocking mechanism 50 may further be affected by the dimensions of the knocking members 52.
  • an elliptical or otherwise eccentrical shaft 50 may of course also be employed.
  • the demoisturizing apparatus of the invention may for instance be incorporated in a mechanical washing and demoisturizing line for e.g. lettuce products, in which the lettuce products are first cut, and subsequently go through a number of baths, in which they are washed, with the products being dried and disinfected in between, after which subsequent demoisturizing may take place in the demoisturizing apparatus of the invention, in which for instance the moisture content is reduced from approximately 30 % to approximately 10 %, after which the products are finally dried to a moisture content of for instance approximately 2 % in a tunnel drier as described in applicant's earlier European patent application bearing publication number EP-A-0 567 197.
  • a mechanical washing and demoisturizing line for e.g. lettuce products, in which the lettuce products are first cut, and subsequently go through a number of baths, in which they are washed, with the products being dried and disinfected in between, after which subsequent demoisturizing may take place in the demoisturizing apparatus of the invention, in which for instance the

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)

Description

The invention relates to a method for mechanically demoisturizing relatively vulnerable products like vegetables, fruits etc. which have a relatively large surface area per unit volume, by imparting an irregular movement to the products and collecting and discharging the moisture that is released by the irregular movement of the products, the irregular movement being imparted to the products by transporting them through a plurality of successive air streams, directed under an angle to their direction of transport, and the moisture being released from the products by blocking the movement of the products in the air streams.
Such a method is known from EP-A-0 058 398. This document discloses a method and apparatus for dewatering and drying solid products, specifically plastic materials granulated under water, wherein the granules are moved through a plurality of adjacent chambers, bounded on one side by arcuate sieves, and defining a twisting path for the granules. The movement of the granules is caused by air streams generated by discharge openings arranged opposite the sieves in each of the chambers. The discarge openings are directed such, that the air streams hit the sieves under an angle, thus causing the granules to be moved both towards and along the surface of the sieves, describing a bouncing trajectory through the chambers. The bouncing movement of the granules cause the adhering water to be shaken off and discharged through the sieves.
The present invention is directed specifically at the mechanical processing of relatively vulnerable products like vegetables, fruits etc. which have a relatively large surface area per unit volume, which may not be subjected to high temperatures during demoisturizing or "dewatering" thereof, like vegetables, fruits etc. and especially of products having a relatively large surface area per unit volume, like lettuce products. It is already known that these products may be mechanically demoisturized by imparting an irregular movement, e.g. shaking or vibrating the products on sieves. The known method of demoisturizing by shaking or vibrating takes a relatively large amount of time, thus decreasing the efficiency of the mechanical processing, and requiring relatively large processing installations for achieving a sufficient throughput. Furthermore, the shaking or vibrating on sieves may easily lead to damaging the generally vulnerable lettuce products.
The invention therefore has for its object to provide a method of the type described above, with which vulnerable products have a large surface area per unit volume, and which may not be subjected to high temperatures, can be efficiently demoisturized. According to the invention this is accomplished in that the products are mechanically moved through the air streams, the air streams being directed substantially perpendicular to their direction of transport and the released moisture is discharged by suction.
An embodiment of the method of the invention which may preferably be applied is described in the dependent claim 2.
The invention also relates to an apparatus for demoisturizing moist products, comprising means for imparting an irregular movement to the products, means for collecting moisture released by the products and means for discharging the collected moisture, the means for irregularly moving the products comprising a plurality of discharge openings for generating air streams, means for transporting the products along the discharge openings, under an angle to the air streams, and means for blocking the movement of the products in the air streams, spaced above the discharge openings in the direction of the air streams.
Such an apparatus is also known from the above-identified prior art document EP-A-0 058 398, where it is used for demoisturizing plastic granulate. Another known apparatus, which is generally used in mechanical washing and demoisturizing lines for e.g. vegetables or fruit, comprises a vibrating or shaking sieve for irregularly moving the products to be demoisturizing or dried, on which the products are advanced through the apparatus, while at the same time the adhering moisture is shaken or vibrated off. The transport capacity of such vibrating or shaking sieves is, however, relatively low, whereas furthermore the danger of damage to the products is considerable.
The invention therefore also has for its object to provide an improved apparatus of the type described above, which apparatus is characterized according to the invention in that the transport means are mechanical transport means directed substantially perpendicularly to the air streams, and the moisture collecting means comprise at least one suction opening.
Preferred embodiments of the demoisturizing apparatus of the invention form the subject matter of the dependent claims 4 through 10.
The invention is now illustrated by means of an example, with reference being made to the annexed drawing, in which:
  • fig. 1 is a partially broken away perspective view of the demoisturizing apparatus according to the invention, and
  • fig. 2 is a partially broken away perspective detail view along the arrow II in fig. 1.
    • An apparatus 1 for demoisturizing or "dewatering" moist products 2 (fig. 1) comprises means for irregularly moving the products 2, means for collecting moisture released by the products, and means for discharging the collected moisture (not shown). The means for irregularly moving the products 2 comprise means for generating an air stream A that varies over time and for guiding this air stream along the products 2, as well as means 16 for transporting the products 2 along the air stream generating means in accordance with the arrow T, substantially perpendicular to the air stream A.
    The means for generating an air stream A and for guiding it along the products 2 comprise a plurality of pressure fans or compressors 3, each of which is connected with its pressure side to a lower part 5 of an inner housing 4. The lower part 5 comprises sloped walls 13 defining a diffuser part 10, which is further bordered by vertical walls 6 and a top wall 7 (fig. 2). The top wall 7 of the lower casing 5 comprises crenelles 8, which are open at the top and thus form discharge openings 9. These discharge openings 9 extend over substantially the entire width of the transport means 16. The discharge openings 9 are spaced in the direction of transport T, whereby the products 2 which are supplied by the transport means 16 will be led through an air stream A several times during transport through the apparatus 1. Thus the products 2 are in fact subjected to an air stream A which varies over time, viz. the full force of the air stream A at the discharge openings 9, followed by a "calm" part of the transport means 16. The transport means 16 incidentally comprise an air permeable belt conveyer 17 which is moveable along the discharge openings 9. This belt conveyer 17 is guided over guide rolls 18-23, and driven by a motor 24.
    As the products 2 are thus subjected to an air stream which varies during transport through the apparatus 1, they will move through the apparatus 1 along a bouncing trajectory, being lifted from the belt conveyer 17 by each air stream A, and subsequently falling back at the following "calm" portion. In order to properly beat loose the moisture present in the products 2, the demoisturizing apparatus 2 further comprises means 27 spaced from the discharge openings 9 in the direction of the air stream A for blocking the upward movement of the products 2. These blocking means 27 comprise a moisture absorbing, air permeable belt conveyer 28 guided along guide rolls 29-32, which may be moved with the lower belt conveyer 17 in the direction of the arrow M, and is driven by a motor 43. As this conveyer 28 blocks the upward movement of the products 2 in the air stream A, the moisture is beaten from the products 2, and subsequently absorbed in the moisture absorbing conveyer 28. Suction openings 33 are arranged behind the moisture absorbing conveyer 28 when seen in the direction of the air stream A, these openings in turn being connected to the means for generating the air stream A. Through these suction openings 33 the moisture that is absorbed in the belt conveyer 28 is drawn off, after which it condenses against the inside of an outer housing 44 surrounding the inner housing 4. The return air R is further led back to the fans or compressors 3. The number of suction openings 33 substantially corresponds with the number of discharge openings 9. The suction openings 33 and the discharge openings 9 incidentally are not arranged opposite each other, but are staggered in the direction of transport T. Also, the air velocity at the suction openings 33 need not be equal to the discharge velocity of the air over the openings 9. The discharge velocity may for instance be selected twice as high as the suction velocity, by selecting a total area of the discharge openings 9 which is approximately half the total area of the suction openings. A demoisturizing apparatus 1 which has proven to be useful in practice may have a discharge velocity in the order of 10 to 70 m/s, preferably 40 m/s, while the suction velocity is 5 to 35 m/s, preferably 20 m/s.
    Between the crenelles 8 the lower casing 5 comprises separation walls 37, which are placed somewhat inwardly of the sidewalls 6 of the lower casing 5, and which divide the space between the crenelles 8 in receptor bins 35 located at the inside, and bypass ducts 14 having discharge openings 36 for cleaning bypass air BL at the outside. This bypass air BL, which is led from the lower casing 5 through openings 38 to the bypass duct 14, and is finally blown out through the openings 36 along the edge of the conveyer 17, serves to prevent the product from assembling along the edge of the conveyer 17 and thus being caught and smeared between the conveyer 17 and the fixed parts of the apparatus 1. Such smearing of the product would in fact lead to the development of bacteria, which might affect the remainder of the products 2 transported through the apparatus 1. It should be noted that the demoisturizing apparatus 1 will usually be installed at the end of a cleaning line for the products 2, so that products leaving the apparatus 1 will generally not be cleaned any further. The receptor bins 35 between the walls 37 also serve to receive products which may fall through the belt conveyer 17, and to prevent these parts of the products from being smeared between the belt conveyer 17 and the fixed parts of the apparatus 1. Furthermore, the bins 35 as a matter of course receive part of the moisture released by the products 2. To further prevent the development of bacteria the belt conveyer may be led through a cleaning installation 25 in its return path, in which for instance a cleaning fluid is sprayed onto the belt by means of spray tubes 26. Cleaning by means of for instance air or UV radiation is also a possibility. It will further be clear that the upper belt conveyer 28 may be subjected to a similar cleaning operation.
    The suction openings 33 are constructed in a similar manner as the discharge openings 9, and are also arranged in crenelles 34, which form part of the bottom wall of an upper part 41 of the inner housing 4. The spaces between the crenelles 34 serve as receptor areas 40, while the walls 39 arranged between the crenelles 34 serve as guidance for the upper belt conveyer 28. In order to maintain a distance between the products 2 and the edge of the conveyer 28, the suction openings do not extend over the full width of the upper conveyer 28. Thus the products 2 are sucked laterally inward somewhat. The moist air drawn off by the suction openings 33 is collected in the upper part 41 of the housing and is led back from there through an opening 42 as return air to the fans or compressors 3, thus forming a closed loop system. The moisture present in the return air condenses against the inside of the outer housing 44. It is of course also possible to construct the apparatus 1 as an open loop system, in which the air that is drawn off is dried and discharged, and the compressors 3 continuously suck in fresh air.
    In order to allow cleaning of the belt conveyer 17, 28 and the various parts 5, 41 of the inner housing 4, an opening 11 is arranged at both sides between the lower part 5 and the upper part 41, which opening is closed off during operation of the apparatus 1 by a door 12, for instance an upwardly and downwardly moveable sliding door. Thus the parts 5, 41 of the inner housing 4 form a closed air duct.
    The inner housing 4 constituted by the lower part 5 and the upper part 41 is completely surrounded by an outer housing 44, which is formed by side walls 45, a bottom 54, a top 46 and front and rear walls 47, 48. Openings 49 are arranged in the front and rear walls 47, 48 for letting through the transport means 16 and moveable blocking means 27. In the outer housing 44 the moisture from the return air R, which mostly condenses against the walls of the housing, is collected and eventually discharged.
    Both the guiding surfaces for the belt conveyers 17, 28 formed by the lower crenelles 8 and the upper crenelles 34 respectively, are arched. This curvature allows the belt conveyers 17 and 28, respectively to be properly tensioned, and thus the risk of the conveyers "floating" on the air stream A is minimized.
    In order to effect a first separation of moisture from the products 2, the apparatus 1 may further comprise mechanical means 50 for irregularly moving the belt conveyer 17 and the products 2 lying thereon. These mechanical moving means 50 comprise a shaft 51, carrying two parallel, eccentric knocking members 52, which will lift the belt conveyer 17 somewhat during rotation of the shaft 51, after which the conveyer will regain its original shape as a result of the tension therein. Thus, a considerable vibrating or shaking movement is imparted to the products. As the belt 17 is relatively light weight when compared to for instance a vibrating or shaking sieve, it can be subjected to fairly considerable accelerations perpendicularly to its plane; thus allowing an effective first separation of the moisture and products. The moisture released during this first separation is directly collected in the outer housing 44.
    As the belt conveyers 17, 28 and the mechanical knocking means 50 are each driven separately, the speed of each of these parts may be independently selected. Thus, an optimum operation of the apparatus 1 can be guaranteed for each kind of product. The blowing and suction force of the compressors 3 may also be separately selected. The amount of moisture separation by the knocking mechanism 50 may further be affected by the dimensions of the knocking members 52. Instead of the shown shaft with knocking members arranged on both sides, an elliptical or otherwise eccentrical shaft 50 may of course also be employed.
    The demoisturizing apparatus of the invention may for instance be incorporated in a mechanical washing and demoisturizing line for e.g. lettuce products, in which the lettuce products are first cut, and subsequently go through a number of baths, in which they are washed, with the products being dried and disinfected in between, after which subsequent demoisturizing may take place in the demoisturizing apparatus of the invention, in which for instance the moisture content is reduced from approximately 30 % to approximately 10 %, after which the products are finally dried to a moisture content of for instance approximately 2 % in a tunnel drier as described in applicant's earlier European patent application bearing publication number EP-A-0 567 197.

    Claims (10)

    1. Method for mechanically demoisturizing relatively vulnerable products (2) like vegetables, fruits etc. which have a relatively large surface area per unit volume, by imparting an irregular movement to the products (2) and collecting and discharging the moisture that is released by the irregular movement of the products (2), the irregular movement being imparted to the products (2) by transporting them through a plurality of successive air streams (A), directed under an angle to their direction of transport (T), and the moisture being released from the products (2) by blocking the movement of the products (2) in the air streams (A), characterized in that the products (2) are mechanically moved through the air streams (A), the air streams(A) being directed substantially perpendicular to their direction of transport and the released moisture is discharged by suction.
    2. Method as claimed in claim 1, characterized in that before being subjected to the air streams (A) an irregular movement is imparted to the products (2) mechanically.
    3. Apparatus (1) for demoisturizing relatively vulnerable products like vegetables, fruits etc. which have a relatively large surface area per unit volume, comprising means for imparting an irregular movement to the products (2), means for collecting moisture released by the products (2) and means for discharging the collected moisture, the means for irregularly moving the products (2) comprising a plurality of discharge openings (9) for generating air streams (A), means (16) for transporting the products (2) along the discharge openings (9), under an angle to the air streams (A), and means (27) for blocking the movement of the products (2) in the air streams (A), spaced above the discharge openings (9) in the direction of the air streams (A), characterized in that the transport means (16) are mechanical transport means directed substantially perpendicularly to the air streams (A), and the moisture collecting means comprise at least one suction opening (33).
    4. Demoisturizing apparatus (1) as claimed in claim 3, characterized in that the transport means (16) comprise at least one air permeable belt conveyer (17) that is moveable along the discharge openings (9).
    5. Demoisturizing apparatus (1) as claimed in claim 3 or 4, characterized in that the blocking means (27) comprise a moisture absorbing and air permeable belt conveyer (28) .
    6. Demoisturizing apparatus (1) as claimed in claim 5, characterized in that the at least one suction opening (33) is arranged behind the moisture absorbing belt conveyer (28), when seen in the direction of the air streams (A) .
    7. Demoisturizing apparatus (1) as claimed in any one of claims 3-6, characterized in that the at least one suction opening (33) is connected to the air stream generating means.
    8. Demoisturizing apparatus (1) as claimed in any one of the claims 3-7, characterized by a plurality of suction openings (33) corresponding to the number of discharge openings (9) and staggered in the direction of transport (T) with respect to the discharge openings (9).
    9. Demoisturizing apparatus (1) as claimed in any one of the claims 4-8, characterized by means (50) arranged upstream of the discharge openings for irregularly moving the belt conveyer (17) moveable along the discharge openings (9).
    10. Demoisturizing apparatus (1) as claimed in any one of claims 4-9, characterized in that the or each belt conveyer (17,28) has a curvature directed at the associated openings (9,33).
    EP96904365A 1995-02-23 1996-02-22 Method and apparatus for demoisturizing moist products Expired - Lifetime EP0811141B1 (en)

    Applications Claiming Priority (3)

    Application Number Priority Date Filing Date Title
    NL9500360A NL9500360A (en) 1995-02-23 1995-02-23 Method and device for dehumidifying moist products.
    NL9500360 1995-02-23
    PCT/NL1996/000085 WO1996026403A1 (en) 1995-02-23 1996-02-22 Method and apparatus for demoisturizing moist products

    Publications (2)

    Publication Number Publication Date
    EP0811141A1 EP0811141A1 (en) 1997-12-10
    EP0811141B1 true EP0811141B1 (en) 2001-04-25

    Family

    ID=19865634

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP96904365A Expired - Lifetime EP0811141B1 (en) 1995-02-23 1996-02-22 Method and apparatus for demoisturizing moist products

    Country Status (4)

    Country Link
    EP (1) EP0811141B1 (en)
    DE (1) DE69612612T2 (en)
    NL (1) NL9500360A (en)
    WO (1) WO1996026403A1 (en)

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    RU171816U1 (en) * 2016-07-04 2017-06-16 Федеральное государственное бюджетное образовательное учреждение высшего образования "Ивановский государственный химико-технологический университет" (ИГХТУ) BAND DRYER FOR PASTE MATERIALS
    DE102005048661B4 (en) * 2004-10-13 2017-06-29 Maag Automatik Gmbh Process for the continuous drying of water-washed granules
    EP3951298B1 (en) * 2019-04-05 2024-08-28 Roda Iberica, S.L. Tunnel for drying fruit and vegetables

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    IT1316197B1 (en) * 2000-06-14 2003-04-03 Turatti Srl APPLIANCE FOR THE CONTINUOUS DRYING OF VEGETABLES, IN PARTICULAR VEGETABLES IN LEAVES.
    WO2002093097A1 (en) 2001-05-17 2002-11-21 Backus Beheer B.V. Apparatus for demoisturizing relatively vulnerable products
    CA2910181C (en) * 2015-05-12 2017-04-25 Cmp Systems, Inc. Fluid removal system
    DE102016122965A1 (en) * 2016-11-29 2018-05-30 Autefa Solutions Germany Gmbh Textile fiber drying
    CN114893953B (en) * 2022-05-09 2024-05-03 山东新成供应链管理有限公司 Drying treatment device for preventing caking for coal dust preparation

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    DE102005048661B4 (en) * 2004-10-13 2017-06-29 Maag Automatik Gmbh Process for the continuous drying of water-washed granules
    RU171816U1 (en) * 2016-07-04 2017-06-16 Федеральное государственное бюджетное образовательное учреждение высшего образования "Ивановский государственный химико-технологический университет" (ИГХТУ) BAND DRYER FOR PASTE MATERIALS
    EP3951298B1 (en) * 2019-04-05 2024-08-28 Roda Iberica, S.L. Tunnel for drying fruit and vegetables

    Also Published As

    Publication number Publication date
    NL9500360A (en) 1996-10-01
    EP0811141A1 (en) 1997-12-10
    DE69612612T2 (en) 2001-10-11
    WO1996026403A1 (en) 1996-08-29
    DE69612612D1 (en) 2001-05-31

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