US3711709A - Irradiation system - Google Patents

Irradiation system Download PDF

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Publication number
US3711709A
US3711709A US00864691A US3711709DA US3711709A US 3711709 A US3711709 A US 3711709A US 00864691 A US00864691 A US 00864691A US 3711709D A US3711709D A US 3711709DA US 3711709 A US3711709 A US 3711709A
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United States
Prior art keywords
vessel
irradiation
walls
set forth
grid
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Expired - Lifetime
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US00864691A
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English (en)
Inventor
W Rudolf
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Sulzer AG
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Sulzer AG
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Publication date
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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
    • F26B17/12—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B9/00—Preservation of edible seeds, e.g. cereals
    • A23B9/06—Preserving by irradiation or electric treatment without heating effect
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2/00—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor
    • A61L2/02—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor using physical phenomena
    • A61L2/08—Radiation
    • 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
    • F26B3/28—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K5/00—Irradiation devices
    • G21K5/02—Irradiation devices having no beam-forming means

Definitions

  • discharge hoppers and knife cylinders are arranged to achieve discharge rates therethrough commensurate with the radiation and flow resistance conditions.
  • This invention relates to an irradiation system. More particularly, this invention relates to an irradiation system for a flowing material, and particularly for granular material.
  • the invention provides an irradiation system having a vessel for directing a flow of material, particularly granular material, therethrough, irradiation members and means for obtaining a substantially constant flow of material through the vessel.
  • the irradiation members are disposed in a pattern substantially perpendicular to the flow direction of the material and extend over the cross section of the vessel so as to irradiate the vessel mainly along the longitudinal axis of the vessel while the radiation dose is distributed substantially uniformly across the vessel crosssection.
  • the irradiation direction of the irradiation members is also oriented substantially upstream and/or downstream of the material flow.
  • a grid formed of hollow tubes is utilized with the tubes oriented in a pattern to obtain the uniformity of radiation dosage.
  • the means to obtain a constant flow of material includes a feeding means at one end of the vessel for introducing granular material into the vessel and a discharge means at the other end for removing the irradiated material from the vessel.
  • the discharge means is formed of a plurality of part discharge means which are spaced across the cross-section of the vessel and are each operated so as to discharge a part flow of material at rates commensurate with the irradiation and flow resistance conditions of the material.
  • Such part discharge means utilize knife cylinders of various constructions to achieve the desired discharge rates.
  • FIG. I illustrates a longitudinal sectional view of an irradiation system according to the invention
  • FIG. 2a illustrates a side view of a knife cylinder utilized in a part discharge means of the invention
  • FIG. 2b illustrates a front fragmentary view of the knife cylinder of FIG. 2a
  • FIG. 3a illustrates a plan view of the discharge means of FIG. 1
  • FIG. 3b illustrates a view taken on line 3b-3b of FIG. 3a
  • FIG. 4a illustrates a plan view of a modified discharge means according to the invention
  • FIG. 4b illustrates a view taken on line 4b-4b of FIG. 4a
  • FIG. 5 illustrates a plan view of a grid according to the invention
  • FIG. 6 illustrates a longitudinal sectional view of a modified vessel according to the invention.
  • FIG. 7 illustrates a side view of the mounting of an irradiation element in a modified grid according to the invention.
  • the irradiation system includes a once-through concrete flow vessel ll of rectangular cross-section which has a lining 2 of stainless steel and a grid 3 disposed approximately at mid-height of the vessel 1.
  • the grid 3 is formed of parallel irradiation members 5 which are supported on opposite sides in the vessel wall 4 across the cross-section of the vessel.
  • the irradiation members '5 comprise a tube 6 in which commercial irradiation elements, for example Cobalt- 60 rods are serially and adjacently disposed (FIG. 5).
  • the vessel 1 is thus irradiated mainly along its longitudinal axis in the upward and downward direction.
  • Each tube 6 adjoins a duct (not shown) in the vessel wall by means of which, and during operating intervals of the system, the irradiation elements are retracted by means of a cable. Spent elements may also be exchanged for fresh elements through such ducts.
  • the tubes 6 are provided with an inclined cover 7 at the upper surfaces. The covers 7 thus serve to ensure passage of the particles through the grid 3.
  • the irradiation members may also be staggered in the vertical direction in order to minimize any flow restriction.
  • the vessel l is provided with a feeding means 10 at the upper end and a discharge means 11 at the lower end for the material.
  • the feeding means It comprises a hopper i2 and a conveyor belt 13 which feeds material such as granular material into the vessel 1.
  • the discharge means 11 extends over the entire cross section of the vessel 1 and includes part discharge means 14, 15, 16, 17 which extend in parallel to the vessel walls 18 and 19.
  • Each part discharge means comprises a hopper 20, 21, 22, 23 of rectangular cross section and an associated knife cylinder 24, 25, 26, 27 respectively.
  • the discharge flow zone of each part discharge means is bounded by two circular curvilinear plates, such as, 30 and 31 between the respective hoppers and knife cylinders.
  • Each knife cylinder comprises a cylinder 32 and radially orientated plates or knives 33 which are uniformly distributed over the cylinder circumference and extend over the entire length of the cylinder 32.
  • the outer edges 34 of the knives 33 extend in parallel to the circumferential lines of the plates 30, 31.
  • the knife cylinders are driven by a common motor (not shown) at the same rotational speed. In operation, the rotation of the knife cylinders causes the pockets 35 formed by adjacent knives 33 to first be filled with irradiated materials and then to be discharged during rotation into a common hopper 40.
  • a conveyor belt 41 is disposed beneath the hopper 40 to receive the material dropping from the hopper 40 so as to deliver the material out of the vessel 1. The quantity of material removed from the vessel is proportional to the rotational speed of the knife cylinders.
  • the conveyor belt 13 of the feeding means 10 driven by a motor 42, continuously feeds the material into the vessel 1.
  • the flowing material is then irradiated upstream and downstream by the irradiation members of the grid 3 and removed from the vessel 1 by the discharge means 11.
  • the speed of the belt 13 is regulated to a constant filler level by means of a contents gauge 43 and regulating means 44 on the side wall of the vessel 1 as shown which influence the output of the motor 42.
  • the tubes 6 of the grid 3 are arranged so that the radiation intensity of the grid 3 in the zone of the two vessel walls in which the irradiation members 5 terminate and which extend perpendicularly to the knife cylinders is less than in the central zone of the grid 3.
  • the knife cylinders 24, 25, 26, 27 are so constructed that the quantity of material delivered thereby is less near these walls than in the center zone of the cross section of the vessel 1. Accordingly, the radiation dose of the material passing the grid 3 near said walls is the same as the radiation dose in the central zone of the cross section where the radiation intensity is greater but the flow rate is also greater.
  • the knife cylinders are provided with displacement members which reduce the volume of the pockets towards the vessel walls. For example, referring to FIGS.
  • a knife cylinder having a pocket 50 between a pair of adjacent knives 51, 52, as above, is provided with a displacement member 53 in the pocket 50 which reduces the capacity of the pocket 50 by the amount of the volume of the member 53.
  • a suitable grading of the displacement member 53 causes its volume to increase gradually towards the two ends of the knife cylinder (FIG. 2b) so that the capacity of the remainder of the pocket becomes correspondingly smaller. The quantity delivered by such a knife cylinder is thus less in the zone of the two vertically extending vessel walls than in the central zone of the vessel.
  • the radiation intensity near the two vessel walls 18, 19 is also less than in the remaining part of the grid, where the radiation of two members each becomes additive.
  • the knife cylinders disposed near the walls 18, 19. it is necessary for the knife cylinders disposed near the walls 18, 19. to be constructed for a smaller delivery rate than the knife cylinders disposed in the central zone of the vessel cross section.
  • the diameters of the cylinders 60 and the displacement member 61, 62 of the two central knife cylinders 63, 64 are smaller than the diameters of the cylinders 67 and the displacement members 68, 69 of the two outer knife cylinders 70, 71.
  • the spacing between the axes of the cylinders 63, 64, 70, 71 remains constant. Accordingly, the throughput in the zone of the parallel vessel walls 18, 19 is less than in the central zone of the vessel cross section and the radiation dose of the material flowing in the various cross sectional zones is uniform.
  • the cylinders 72 and the displacement members 73, 74 mounted thereon can be of the same size for all knife cylinders.
  • the knife cylinders in the central zone of the vessel cross section are disposed more closely adjacently than near the walls 18, 19;
  • the distance a between the axes of the middle knife cylinders 75, 76 is smaller than the distance b between the axes of the outer cylinders 77, 78 and the middle cylinders 75, 76.
  • the quantity discharged in the central zone of the cross section is therefore greater than near the wall and the radiation dose received by the material is therefore uniform over the cross section.
  • the irradiation members in the grid in order to improve the uniformity of the radiation dose over the cross section of the vessel 1 still further it is possible, on the one hand, for the irradiation members in the grid to be disposed more closely adjacently relative to the parallel extending vessel walls 18, 19 and, on the other hand, for the radiation elements disposed in the irradiation members to be disposed more closely adjacently relative to the perpendicularly extending vessel walls.
  • the outer irradiation members 80, 81 of the grid 82 are disposed near the parallel vessel walls 18, 19 but more closely adjacently than the irradiation members 83, 84 in the central zone of the grid.
  • the outer radiation members 85, 86 in each tube are also disposed more closely adjacently than the radiation elements 87, 88 in the central zone of the grid. The resultant radiation distribution therefore becomes more uniform over the entire grid.
  • the vessel 100 in order to maintain a oncethrough flow vessel which is loaded in an intermittent manner as by a bucket means, as shown, filled at a constant level, the vessel 100 is provided with an integral hopper 101 atthe upstream end.
  • This hopper 101 can be periodically fed and thus can function as a buffer volume.
  • A'shielding member 103 is disposed downstream of the discharge. opening 102 of the hopper 101 in order to prevent material stored in the hopper 101 from being prematurely exposed to radiation.
  • the discharge means 104 which is constructed as above
  • the material will leave the hopper through the ducts 105, 106, disposed between the shielding member 103 and upper walls of the vessel 100.
  • Uniformity of the radiation dose applied to the material over the cross section of the vessel may also be obtained by each knife cylinder being associated with a motor (not shown) whose rotational speed is adapted to the radiation intensity of that zone of the grid which extends over the knife cylinder.
  • the rotational speed of the respective motors would be reduced towards the walls extending in parallel to the knife cylinders where the radiation intensity is less.
  • the discharge of material at that position will therefore also be less than in the central zone of the vessel cross section and the radiation dose will once again be uniform.
  • each tube 110 is of rectangular cross section and the irradiation elements lllll disposed therein are accordingly constructed of flat, rectangular cross section 112.
  • two sheet metal webs 113 connect each tube 110 to a rod 114 so that together they form a supporting member 115 which is resistant to bending. Owing to the small height h of the irradiation elements 111, the self-absorption of radiation in the direction of the height h is small and the intensity of the radiation discharged in this direction, that is, in the direction of the longitudinal axis of the vessel, is large.
  • the invention thus provides an irradiation system which has a very high irradiation efficiency due to the absence of absorbing intermediate walls. Since such walls are eliminated, the entire construction of the system is simple and the use of expensive, non-corrosive material is reduced to a minimum. Also, since the material requires only a uniform flow rate, adjustment and stabilization of the rate can be simply performed by regulating the supply and delivery of the material.
  • the invention further provides an irradiation system in which the processed material is only slightly mechanically stressed.
  • Radioactive irradiation apparatus including a flow vessel having walls for directing a flow of material therethrough; feeding means for supplying the material into said vessel; and a discharge means extending over the entire cross-section of said vessel for obtaining a constant rate of flow through said vessel; and a grid of spaced parallel tubes containing irradiation elements, said grid extending at right angles to the flow path of the material to be irradiated over the entire cross-section of said vessel for emitting radiation upstream and/or downstream of said grid, at least one of said tubes and said elements being oriented in said grid with a closer relative spacing near said walls of said vessel than in the central region of said vessel whereby said grid is adapted to meet varying radiation conditions prevailing over the cross-section of said vessel to obtain a nearly uniform radiation dosage in the material to be irradiated flowing through said vessel.
  • each part discharge means includes a hopper and a rotatably mounted knife cylinder in a discharge zone of said hopper, said cylinder having a plurality of knives extending approximately radially over the length of said cylinder to form pockets therebetween.
  • An irradiation system as set forth in claim 5 which further comprises displacement members in respective ones of said pockets, said displacement members having cross sectional dimensions which increase towards the walls of said vessel extending perpendicularly of said knife cylinder.
  • each said cylinder is of increased diameter than an adjacent cylinder relative to the walls of said vessel parallel to said cylinders.
  • An irradiation system as set forth in claim 5 further comprising a motor connected to each knife cylinder, whereby the rotational speed of each motor can be adapted to the radiation intensity of the grid zone about the respective knife cylinder.
  • feeding means includes a storage hopper upstream of said vessel having a discharge opening and a radiation shielding member for substantially preventing the material in said hopper from being exposed to irradiation from said vessel.
  • An irradiation system for granular material comprising a flow vessel for directing a flow of material therethrough;
  • irradiation members disposed in said vessel in a pattern perpendicularly to the flow direction of the material and extending over the cross section of said vessel, the irradiation pattern of said members being oriented in at least one direction of an upstream direction and a downstream direction;
  • said means for obtaining a substantially constant flow of material through said vessel, said means including a feeding means for introducing granular material into said vessel and a discharge means for removwherein said discharge means includes a plurality of part discharge means for regulating the discharge of material therethrough in relation to the irradiation and flow resistance conditions of the material.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Mechanical Engineering (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Zoology (AREA)
  • Microbiology (AREA)
  • Public Health (AREA)
  • General Health & Medical Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Physics & Mathematics (AREA)
  • Epidemiology (AREA)
  • Wood Science & Technology (AREA)
  • Veterinary Medicine (AREA)
  • Chemical & Material Sciences (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
  • Apparatus For Disinfection Or Sterilisation (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)
  • Processing Of Solid Wastes (AREA)
  • Cereal-Derived Products (AREA)
US00864691A 1968-10-10 1969-10-08 Irradiation system Expired - Lifetime US3711709A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1513368A CH497768A (de) 1968-10-10 1968-10-10 Bestrahlungsanlage, insbesondere für körniges Gut

Publications (1)

Publication Number Publication Date
US3711709A true US3711709A (en) 1973-01-16

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US00864691A Expired - Lifetime US3711709A (en) 1968-10-10 1969-10-08 Irradiation system

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US (1) US3711709A (de)
JP (1) JPS4926240B1 (de)
CH (1) CH497768A (de)
DE (1) DE1803052B2 (de)
FR (1) FR2020285A1 (de)
GB (1) GB1281047A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5434421A (en) * 1990-01-31 1995-07-18 Gesellschaft Fuer Unweltschutzberatung Und -Technik Gbr Process and device for treating particulate material with electron beams
US5503800A (en) * 1994-03-10 1996-04-02 Uv Systems Technology, Inc. Ultra-violet sterilizing system for waste water
WO2009116923A1 (en) * 2008-03-19 2009-09-24 Skåne-Möllan Ab Device and method for microwave treatment of grain

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1536989A (en) * 1976-10-05 1978-12-29 Westlake Agricultural Eng Flow control meters for gravity flow particle dryers
FR2498876A1 (fr) * 1981-02-04 1982-08-06 Novatome Ind Dispositif d'irradiation de produits agricoles, sur les lieux de production
NZ200681A (en) * 1981-06-19 1987-03-06 Westelaken C Gravity flow grain dryer with two stages of drying
DE8801404U1 (de) * 1988-02-05 1988-08-18 Maaßen, Egon, 2000 Hamburg Kinematisch visuelle Unterhaltungsvorrichtung
DE19711044A1 (de) * 1997-03-04 1998-09-10 Schulz Verfahrenstechnik Gmbh Apparat für kontinuierlich oder diskontinuierlich ablaufende Stoff- und/oder Wärmeübergangsprozesse

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1817936A (en) * 1926-06-02 1931-08-11 Borden Co Method of irradiating milk solids with ultra-violet rays and the product of such method
US2279810A (en) * 1940-06-28 1942-04-14 Westinghouse Electric & Mfg Co Method and apparatus for efficiently sterilizing air in ducts
US3360646A (en) * 1965-01-29 1967-12-26 Earl M Reiback Uniform gamma irradiation of bulk grain material
US3527940A (en) * 1965-02-26 1970-09-08 Saint Gobain Techn Nouvelles Method and apparatus for irradiating fluent materials through a helical path

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1817936A (en) * 1926-06-02 1931-08-11 Borden Co Method of irradiating milk solids with ultra-violet rays and the product of such method
US2279810A (en) * 1940-06-28 1942-04-14 Westinghouse Electric & Mfg Co Method and apparatus for efficiently sterilizing air in ducts
US3360646A (en) * 1965-01-29 1967-12-26 Earl M Reiback Uniform gamma irradiation of bulk grain material
US3527940A (en) * 1965-02-26 1970-09-08 Saint Gobain Techn Nouvelles Method and apparatus for irradiating fluent materials through a helical path

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5434421A (en) * 1990-01-31 1995-07-18 Gesellschaft Fuer Unweltschutzberatung Und -Technik Gbr Process and device for treating particulate material with electron beams
US5503800A (en) * 1994-03-10 1996-04-02 Uv Systems Technology, Inc. Ultra-violet sterilizing system for waste water
WO2009116923A1 (en) * 2008-03-19 2009-09-24 Skåne-Möllan Ab Device and method for microwave treatment of grain

Also Published As

Publication number Publication date
GB1281047A (en) 1972-07-12
FR2020285A1 (de) 1970-07-10
DE1803052B2 (de) 1973-11-29
DE1803052A1 (de) 1970-08-06
CH497768A (de) 1970-10-15
DE1803052C3 (de) 1974-07-04
JPS4926240B1 (de) 1974-07-06

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