US3704523A - Microwave dryer for ceramic articles - Google Patents

Microwave dryer for ceramic articles Download PDF

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Publication number
US3704523A
US3704523A US105391A US3704523DA US3704523A US 3704523 A US3704523 A US 3704523A US 105391 A US105391 A US 105391A US 3704523D A US3704523D A US 3704523DA US 3704523 A US3704523 A US 3704523A
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Prior art keywords
air
chamber
microwave
chambers
molds
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US105391A
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English (en)
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Michel Henri Guerga
Bernard Lucien Desire Hallier
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Alcatel Lucent NV
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International Standard Electric Corp
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Assigned to ALCATEL N.V., DE LAIRESSESTRAAT 153, 1075 HK AMSTERDAM, THE NETHERLANDS, A CORP OF THE NETHERLANDS reassignment ALCATEL N.V., DE LAIRESSESTRAAT 153, 1075 HK AMSTERDAM, THE NETHERLANDS, A CORP OF THE NETHERLANDS ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: INTERNATIONAL STANDARD ELECTRIC CORPORATION, A CORP OF DE
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/78—Arrangements for continuous movement of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
    • B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
    • B28B11/241—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening using microwave heating means
    • 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
    • F26B3/32—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action
    • F26B3/34—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action by using electrical effects
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2206/00—Aspects relating to heating by electric, magnetic, or electromagnetic fields covered by group H05B6/00
    • H05B2206/04—Heating using microwaves
    • H05B2206/046—Microwave drying of wood, ink, food, ceramic, sintering of ceramic, clothes, hair
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/60—Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes

Definitions

  • ABSTRACT A process and an apparatus are provided for drying molded ceramic objects using a combination 'of microwave heating and air ventilation.
  • the objects are heated rapidly in a first microwave cavity oven while applying a relatively light flow of air.
  • the objects are then maintained at a constant temperature in a second microwave oven while applying a heavy flow of air to evaporate water.
  • the oven cavities are in a common enclosure divided by a partition with separate magnetron generators mounted in each portion. Ventilating ducts connected to an air source supply air to the cavities. Molds carrying the objects are fed by a belt into each cavity in a controlled heating and drying sequence to produce large quantities'of ceramic objects with minimum cracking and warping. The power and space requirements are also reduced.
  • the present invention concerns a process and equipment for microwave heating principally for the predrying of ceramic pastes used for the manufacture of chinaware pieces of moderate dimensions such as plates, dishes or electric ceramic pieces.
  • the source of microwave energy is constituted by tubes such as magnetrons or klystrons operating at certain frequencies reserved for industrial heating, for example 2450 Mc/s.
  • the predrying is carried out in free air, the water in the paste being eliminated as much by slow evaporation as by absorption in the pores of the mold.
  • the operation was completed when the object could be taken from the mold without effort and possessed sufficient rigidity to be placed on an appropriate form with a view to complete drying.
  • the predrying was a lengthy portion of the manufacture which required much handling, extensive workshops with numerous stages, and quantities of molds the stock of which had to be renewed quite rapidly due to progressive fouling of the plaster and its decomposition under the effect of the absorbed moisture.
  • Porcelain manufacturers have sought to reduce the duration of the predrying by subjecting the molds to infrared radiation and/or a flow of dry hot air.
  • the evaporation of water is a surface phenomenon which forms a surface crust preventing the elimination of the water from the interior of the paste. Shrinkage is badly effected and cracks and warpings appear.
  • certain manufacturers have attempted to place the objects and molds in a current of hot and humid air. The operation actually becomes longer and does not offer any advantages over the traditional method of predrying in free air.
  • the temperature of the humid object Due to the use of this process within microwave ovens, only the temperature of the humid object is increased to the almost total exclusion of that of the surroundings and support structure to the object.
  • the support is actually only heated in the zone of contact with the object, where the humidity can diffuse into the adjacent capillaries.
  • the paste should be heated to a temperature as high as possible to increase the speed of transfer of the water.
  • the paste is'altered and the production output may be decreased by reason of important defectsthat are only noted inthe last stages of manufacture of the porcelain objects.
  • the temperature not to be exceeded is of theorder of 65 C.
  • the object of the invention is to provide a device for the drying of ceramic pastes, including a source of microwave energy which assures theheating of the paste in its bulk and a source of evaporation energy constituted by a flow of relatively dry air which circulates at the surface of the pastes to be dried.
  • Another object of the invention is to provide means which allow the drying device to proportion the duration and quantity of the respective action of the microwave energy and evaporation energy in such a way as to consume, for a given rate of production, the least possible of the more expensive microwave energy.
  • the devices of the present invention permit reduction of the time for drying of ceramic pastes, improving the quality, decreasing the wastage, freeing-the molds very rapidly so that they deteriorate-much less quickly than when used in usual drying stations. There results an important decrease in the number of molds necessary and a great reduction in thefloor space occupied by the equipments.
  • molds loaded with ceramic paste are placed in a metallic enclosure comprising first and second cavities separated by a metallic partition.
  • the heating of the paste is produced in the first cavity under the effect of radiation from a first set of microwave sources made up, for example, of magnetrons.
  • a sufficient and homogeneous temperature in the paste is maintained in the second or evaporation cavity, under the effect of radiation from a second set of microwave sources also made up for example'ofmagnetrons.
  • Each cavity is supplied with its own ventilation device of pulsed dry air, the flow of which is regulatable, and the two flows can be very different.
  • the two cavities can be raised and lowered together, which allows the loading of a batch of molds furnished with ceramic paste in the first cavity.
  • a batch of molds containing ceramic pieces suitably dried comes out of the second cavity.
  • the displacement of the batches is assured by a system of discontinuous stepped advancement, the movement of which is controlled and initiated from a program chamber in which the duration of the lowering of the set of cavities, the microwave energy to be dissipated in each of the cavities and the two flows of evaporation air, are set for each step.
  • the molds are supported by a metal band with discontinuous advance.
  • the two cavities are open at the lower part and when lowered, the walls, which are provided with a metallic braid, come to rest, under pressure, on the metal band.
  • This device considerably lessens parasitic microwave radiatiomthe pressure being regulated in such a way as to obtain the minimum parasitic radiation.
  • the magnetrons of the microwave sources are automatically put into operation when the pressure is sufficient due to a control in the program chamber.
  • the magnetrons and their coupling circuits with the two cavities are supported by the ceiling of the latter.
  • the ceiling of each of the cavities there are also fixed pulsed air inlets in the form of adaptation cones which cover all the available surface to the exclusion of that which is occupied by the magnetrons.
  • the cooling of the magnetrons is provided by independent ventilation.
  • the pulsed air penetrates into each of the cavities via a multitude of small holes whose linear dimensions are very much less than the microwave length (cut off holes).
  • the pulsed air, sweeping over the objects to be dried is evacuated by an extraction device made up of adaptation cones placed on the lateral boundaries of the two cavities and aerodynamically coupled to the interior of the latter by a multitude of cut-off holes.
  • the flow of incoming and extraction air can be regulated in each of the cavities by shutters whose movement is controlled in the program chamber.
  • the set of sources which feed the first heating cavity with microwave energy preferably supply varying operating periods and a power substantially higher than the set of sources which feed the second evaporation cavity, whilst the flow of ventilated air in the heating 'cavity is substantially lower than the flow of ventilated air in the evaporation cavity.
  • the two cavities have independent microwave sources and relatively incoherent phases. This independence results mainly from the fact that the objects to be dried con stitute a high-absorbent and low reflecting layer at the bottom of the cavity as regards microwave energy.
  • the use of several well distributed independent sources reduces the risk of standing waves, which is much less as the number of sources increases.
  • the magnetrons feeding the first cavity are four in number distributed on the diagonals of the rectangular ceiling and the magnetrons feeding the second cavity are three in number distributed on a single diagonal of the ceiling. These dispositions of the magnetrons are chosen in such a way as to assure that the density of microwave energy absorbed by the humid pastes is almost equal at all the points of the space occupied by the loaded molds.
  • FIG. 1 shows a schematic view of a set of drying equipment according to the invention
  • FIG. 2 shows an enclosure with two parallelepiped cavities of equal dimensions having magnetrons supported on the ceilings and coupled to the cavities
  • FIG. 3 shows the detail of a circuit coupling a magnetron with a cavity
  • FIG. 4 shows devices for entry and extraction of pulsed air according to the invention
  • FIG. 5 shows a curve of temperature of the ceramic paste during passage in a drying device according to the invention
  • FIG. 6 shows a detail of the embodiment of one variant of the device of FIG. 4,
  • FIGS. 7, 8 and 9 show support devices for the molds
  • FIG. 10 shows a detail of the system for extracting dried pieces.
  • the drying equipment using generally. It supports a lower section la including a transfer assembly having a motor 2 which controls a driving device 3 and a transporter band 4 of stainless steel which rolls around pulleys 5 and 5.
  • the upper part lb carries lifting elements like a hydraulic jack 6a, integral with an assembly of beams 6b, allowing the pressure forces to be uniformly distributed, and controlled by a hydraulic power group 7.
  • lb also carries the power supplies 8 for the magnetrons, a source of pulsed air ventilation 9, an extraction output 9' for air, and a program chamber 10 in which are stored all the control instructions for the different units of the equipment.
  • a microwave enclosure 11 in parallelepiped form. It is generally in duraluminum or of another good conducting material and is of a height between three and six times the height of the product to be dried in molds. The other dimensions depend on the quantityof the product to be treated in each batch of plates to be dried.
  • the enclosure is divided into two equal cavities l4 and 15 by a metal partition 13.
  • microwave sources 12 or 12 On the roof of the cavities are disposed microwave sources 12 or 12 each constituted by a magnetron associated with a microwave circuit coupled by slots to the corresponding cavity. Enclosure 11 and the units that it carries can be raised by the hydraulic jack 6a and the assembly of beams 6b.
  • Each power supply 8 is connected to the correspond ing magnetron 12 or 12 by'flexible cables 16.
  • the piping for directing ventilated air on the objects to be dried is also supported by'the roof of the enclosure 11. It is not shown in FIG. 1 but will be described below in connection with FIG. 4.
  • the pipes are connected together by bellows at the pulsed air source 9.
  • the assembly lb is surrounded by a protective grid not show.
  • the doors l7 and 17' allow the introduction into the furnace of objects to be dried or the removal from the furnace of dried objects when the enclosure 11 is raised.
  • the enclosure 111 is lowered and comes into contact with the metal band 4 through a metal braid l8 soldered on the edges of the open face of the cavities l4 and 15.
  • the force of pressure of the enclosure ll on the band 4 is controlled by the hydraulic jack 6a and measured by means of a dynamometer now shown.
  • FIG. 2 shows the parallelepiped enclosure 11 divided by the partition 13 into two cavities l4 and 15 of equal dimensions.
  • the roof of the cavity 114 are placed four microwave sources 12 each composed of a magnetron coupled to a microwave circuit constituted by a section of wave guide and itself coupled by windows to the cavity 14.
  • the representationv of each source l2 has been limited to a parallelepiped box surmounted by a cylinder which symbolize respectively the microwave circuit and the magnetron.
  • FIG. 3 provides an exploded view of a known example of a source 12.
  • the magnetron 12a provided with its magnet 12b is terminated by an antenna which couples the magnetron to the microwave circuit 124 made up of a section of wave guide short circuited at its two ends. 12d is coupled to the cavity M by four windows ll2e. Pipes 12f provide circulation of cooling water for the magnetron 12a.
  • a well known stirrer device not shown in FIG. 3. It includes a moveable reflector, made up of turning plates which move across windows 12a. The stirrer" moves the standing waves that are produced in the cavity loaded with the material to be heated so that the waves do not keep the same configuration in time. This reduces the effects of an unequal distribution of the microwave energy.
  • the four sources 12 are placed in diagonal pairs on the roof of the cavity 14.
  • the center of each of the boxes which symbolize the microwave circuits of the sources is situated at approximately mid-distance from the center and from one of the vertices of the rectangular roof.
  • On the roof of the cavity 15 are placed three microwave sources 12 which may be the same as sources 12.
  • the three sources 12 are placed on one of the diagonals of the roof of the cavity 15.
  • the center of one of the boxes which symbolize the microwave circuits 12' is the same as the center of the rectangular roof.
  • the center of each of the two others is situated approximately at two thirds of the distance between the center and one of the vertices of the rectangular roof. The disposition of the microwave sources radiating in the two cavities 14 and l-and variants of these positions will be described later.
  • FIG. 4 shows the enclosure 11 with a ventilation system.
  • the four inlets 19 of relatively large dimensions, only three of which are shown.
  • the four inlets 19 and four adaptation cones 20, which transmit'air between the inlets and cavity 14, cover the entire surface of the roof 14 surrounding the microwave sources 12. In other devices, the four cones 20 cover only the surface of the roof left free by the sources 12.
  • the transmission of air between the cones 20 and the cavity 14 is made through the roof by means of small holes 21, called cut-off holes.
  • the linear dimensions of the holes are made small compared with the length of a microwave to avoid any parasitic radiation outside the cavity.
  • the dimensions of the holes 21 and their distribution are in such that the flow of air arriving in the cavity shall be as uniform as possible.
  • the four inlets 19 are branched from a larger pipe 22 which is connected through bellows 23 to the source 9 of pulsed air of FIG. 1, this source being provided, for example, with a suction ventilator.
  • Air penetrating into cavity 14 is extracted through further adaptation cones such as 25 which are distributed around the base of the cavity 14 on the three accessible vertical walls.
  • the cones 25 are coupled aerodynamically with the cavity by a multitude of small cut-off holes 26.
  • Pipes 27 connect the cones 25 to a larger pipe, not shown, and through a bellows to the air extraction device 9' of FIG. 1, which device is provided with an extraction ventilator.
  • Shutters 28 allow adjustment of the quantities of air extracted by each of the cones 25.
  • Cavity l5 incorporates the same apparatus including air inlets 19, adaptation cones 20, cut-off" holes 21, shutters 24, with the air inlets 19' forming branches of the large pipe 22.
  • adaptation cones 25' are coupled aerodynamically to the cavity by holes 26', pipes 27 connect the cones 26' to the larger pipe which is connected to the air extraction device 9' of FIG. 1.
  • Shutters 28' allow adjustment of the quantities of air extracted by each of the cones 25.
  • the respective openings of the shutters 24, 24, 28 and 28' allow different flows of air in the two cavities 14 and 15 to be obtained.
  • the magnetrons of the microwave sources 12 and 12 should preferably be cooled by a fluid circulation independent from that which causes evaporation of the water.
  • two pipes 29 which carry water for cooling the magnetron of 12.
  • FIG. 6 shows schematically an example of double ventilation. This includes an air input 19, an adaptation cone 20, cutoff holes 21 and a source 12. The partial flow of air, derived from the main flow, which goes to cool the magnetron 12 is guided by an adaptation cone 30 covering the assembly of the source 12, A shutter for regulating the partial flow of air may be placed at the apex of 30.
  • FIG. 1 shows the support units for the ceramic pieces to be dried.
  • the pieces enter by a door 17 and leave by door 17.
  • the pieces coming from the machine which shapes the paste and places the plaster molds are collected in batches on the metal band 4 at the left of the drier.
  • the molds 31' carrying plates 32 are arranged on a platform 33 of low dielectric loss plastic material, polypropylene, amongst others, having extensions 34 of the same material.
  • the platform 33 supported by the extensions is placed on the metal band.
  • FIG. 8 shows another embodiment in which the metal band is providedwith elements 35 which support the platform 33, 33 and 35 also being of plastic material.
  • FIG. 9 shows a variant of the support of molds loaded with paste.
  • the band 4 is replaced by a fixed metal plate 36 on which can be lowered the enclosure 11 to contact the plate through the metal braid 18.
  • Two metal ribbons 37 and 37 of very small thickness, are provided with elements 38 and 38' and can slide on 36.
  • the plastic material platforms 33 of FIGS. 7 and 8 are supported by elements 38 and 38.
  • the small thickness of the ribbons 37 and 37' allows good contact between the plate 36 and the assembly 11 when the latter is lowered.
  • the pieces coming from the machine for shaping the ceramic paste may have, for example, a mass of 800 g including 600 g of kaolin and clay and 200 g of water.
  • the predrying is finished when the ceramic piece is sufficiently rigid to be extracted from the support mold, which results in the evacuation of g of water per piece.
  • the plaster mold has a mass of about 2 kg.
  • the supplementary energy to be supplied per plate is raised to 90 kilojoules, or for 600 plates, 54,000 k! or 15 kW/h. In the known processes the necessary energy will thenbe increased to about 50 kW/h.
  • the operation commences when the metal band 4 is stopped.
  • the molds carrying the plates to be dried coming from the special shaping machine, such as a Roller machine, are manually or automatically placed on a platform 33 of plastic material (FIGS. 7 and 8).
  • the platform is placed on the loading area situated at the left of the metal band 4.
  • theenclosure 11 is raised, the band .4 is set into motion and stopped when the platform 33 is in place under the cavity 14. The band4 being stopped,
  • a security device allows the operations to continue only if the pressure of the enclosure on the band 4 is sufficient.
  • the four magnetrons of the sources 12 on the roof of the cavity 14 are started simultaneously.
  • the three magnetrons carried by the cavity 15 may also be started at the same instant.
  • the operation of the magnetrons is stopped under control of a security or locking device, with the enclosure 11 being raised.
  • 11 has reachedits maximum height the band 4 is started again and a new batch of plates to be dried, carried by another platform 33, is engaged under the cavity 14 while the first batch passes under the cavity 15.
  • platform 33 carrying the empty molds is then conveyed towards the special Roller shaping machine by a transporter band.
  • each batch comprises 30 plate-mold assemblies.
  • the time t of passage of one batch under each of the cavities 14 and 15 is 150 seconds and the time t of the operations of raising the enclosure 11, displacement of the band 4, lowering of 11 and again setting the magnetrons into operation, is 60 seconds. Roughly it can be said that every 3 minutes 30 plates ready to be removed from their molds come out on the right of band 4, which is at a rate of 600 dried plates per hour.
  • each of the cavities are about 3m in length, lm in width-and 0.6m in height.
  • the flow of pulsed air for the assembly of the two cavities is of the order of 2000m /hour.
  • an efficiency of percent corresponds to' 10 kW of power radiated in 14.
  • the three magnetronsof sources 12 feeding cavity 15, FIGS. 2 and 4, with microwave energy also each have a nominal power of 2.5 kW.
  • sources 12' Taking. into account the role played by the microwave heating in cavity 15, which is intended to keep constantthe bulk temperature of the plates, the energy required of sources 12' is generally less than that furnished by the sources 12 which radiate into the cavity 14. In order to economize on the expenditure of energy, sources 12' can be made to operate less time during each elementary operation than sources 12. The power .to the magnetron at the center of the roof of cavity 15 can then be less thanthat of each of the two others. This latter solution has another advantage which will be examined later. It also permits obtaining a better distribution of the microwave energy dissipated in the plates placed in cavity 15.
  • the microwave energy consumed rises to 2 X 7 X 5/6 12 kW/h. If this result be compared with the ideal values estimated above, 9 kW/h for the heating of the paste and 33 kW/h for the vaporization of 50 kg of water, it is seen that the microwave energy is used efiiciently in accordance with the system of the invention. The difference of 3 kW/h can be explained by losses in the metal boundaries of the cavities and in the plaster of the molds and also by a small vaporization energy supplied to the internal water, this vaporization being used to facilitate the migration of water toward the surface.
  • the characteristics of the present system for drying ceramic plates of a different nature from the present examples will be determined as a first approximation by simple empirical laws.
  • a fixed quantity of water to be evaporated during a unit of time it is possible to calculate the flow of pulsed air when the surface of the elements to be dried and the temperature of the air are known. This calculation is made by using the fonnula A noted above.
  • the quantity of paste to be heated during a unit of time to reach a suitable temperature, and timing of the operations of raising and lowering of the enclosure permit determining an approximate value, of the necessary microwave power.
  • the total power for the assembly of microwave sources is made greater by 50 percent than that calculated. This microwave power is then distributed between the two cavities by attributing a higherpower to the first cavity 14,.FIGS. l, 2, 4, in which the rapid rise of the temperature of the paste is mainly effected.
  • a first known means is the introduction into the radiation enclosures of move: able reflectors or stirrers which act as wave mixers and limit the effect of standing waves.
  • a second means which should also accompany the first, consists in using n independent sources in place of a single one. At any point whatever inside a cavity, the n microwave fields are combined but with incoherent phases which limits the risks of appearance of standing waves,n should be made as high as possible.
  • each source which depends on the nature of the coupling windows between the microwave circuit associated with a magnetron and the cavity, (see FIG. 3), is directive and the elements placed vertically in relation to a source receive more energy than the others.
  • the most suitable distribution is that which has been described.
  • the one placed in the center of the roof of the cavity, as shown in FIG. 2 will preferably have a power substantially less than that of each of the two others.
  • a process for drying ceramic articles and molds using microwave heating and air ventilation comprising:
  • Apparatus for drying ceramic articles and molds comprising:
  • first and second microwave heating chambers positioned adjacent one another and having a common partition therebetween, first and second microwave radiation means coupling different levels of microwave energy into respective said chambers, first and second air ventilating means directing different levels of air flow into said respective chambers, means feeding a mold containing a ceramic article into said first and second chambers in a discontinuous stepped sequence, said chambers being capable of operating simultaneously on different successive articles and molds, said feeding means includes a discontinuously advancing platform supporting and enclosing the base of said chambers, means providing electrical contact between said platform and chambers, means raising and lowering said chambers relative to said platform to make and break said contact and means for actuating and controlling the application of microwave energy and ventilating air to heat and dry each said mold and article.
  • said air ventilating means includes a common source of air and means directing a relatively light flow of air from said source into said first chamber and a relatively heavy flow of air into said second chamber, said microwave means coupling a relatively higher energy level into said first chamber and lower level into said second chamber.
  • said microwave means includes a plurality of magnetrons mounted on the roof of each said chamber.
  • said air directing means includes air ducts, shutters in said ducts, and adaptation cones positioned over said magnetrons and chambers, a plurality of holes in the roofs thereof, and air extraction means positioned in each said chamber.
  • said platform includes dielectric supports and a plurality of articles and molds disposed on said supports, said platform providing movement of groups'of said plurality of articles and molds into and out of said chambers in sequence.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mechanical Engineering (AREA)
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  • Physics & Mathematics (AREA)
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  • Electromagnetism (AREA)
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  • Ceramic Engineering (AREA)
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US105391A 1970-01-14 1971-01-11 Microwave dryer for ceramic articles Expired - Lifetime US3704523A (en)

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FR7001187A FR2076405A5 (ja) 1970-01-14 1970-01-14

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Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3935060A (en) * 1973-10-25 1976-01-27 Mcdonnell Douglas Corporation Fibrous insulation and process for making the same
US3953703A (en) * 1974-10-03 1976-04-27 Materials Research Corporation Method for drying ceramic tape
US4043380A (en) * 1973-11-28 1977-08-23 Valentine Match Plate Company Production of plaster molds by microwave treatment
US4057702A (en) * 1973-10-31 1977-11-08 Automatisme & Technique Process and plant for the fritting of ceramic products
US4176267A (en) * 1978-05-12 1979-11-27 Armstrong Cork Company Microwave energy trap
US4180918A (en) * 1978-10-06 1980-01-01 Caterpillar Tractor Co. Microwave drying of ceramic shell molds
US4210793A (en) * 1978-03-06 1980-07-01 Agence Nationale De Valorisation De La Recherche (Anvar) Microwave applicator for radiating microwaves to an elongated zone
US4259560A (en) * 1977-09-21 1981-03-31 Rhodes George W Process for drying coal and other conductive materials using microwaves
EP0028267A1 (de) * 1979-10-05 1981-05-13 Heinrich Wagner Maschinenfabrik GmbH & Co Vorrichtung zur Trocknung von Giessereiformen und -kernen
US4728531A (en) * 1986-11-04 1988-03-01 Ford Motor Company Method of drying refractory coated foam patterns
US4772770A (en) * 1986-06-30 1988-09-20 Kabushiki Kaisha Toyota Chuo Kenkyusho Apparatus for joining ceramics by microwave
US4847460A (en) * 1987-04-02 1989-07-11 Leybold Aktiengesellschaft Apparatus for injecting microwave energy by means of an open microwave guide
US4896005A (en) * 1988-03-31 1990-01-23 Hermann Berstorff Maschinenbau Gmbh Method and apparatus for the continuous heating, pasteurization or sterilization of foodstuffs or the like by microwave energy
US5525783A (en) * 1993-05-07 1996-06-11 Tran Industrial Research Inc. Microwave heating device for lime and calcining
US5541390A (en) * 1995-03-20 1996-07-30 Cidelcem Industries Tunnel oven for microwave heating and cooking foods
US5911941A (en) * 1997-04-10 1999-06-15 Nucon Systems Process for the preparation of thick-walled ceramic products
WO2001049077A1 (en) * 1999-12-28 2001-07-05 Corning Incorporated Hybrid method for firing of ceramics
US6344635B2 (en) 1999-12-28 2002-02-05 Corning Incorporated Hybrid method for firing of ceramics
US20040104514A1 (en) * 2002-11-19 2004-06-03 Denso Corporation Method and apparatus for drying ceramic molded articles
US20040206755A1 (en) * 2003-04-18 2004-10-21 Hadinger Peter James Microwave heating using distributed semiconductor sources
EP1645348A1 (de) * 2004-10-05 2006-04-12 MK Technology GmbH Verfahren und System zum Herstellen einer Schalenform insbesondere für das Feingießen
EP1530015A3 (en) * 2003-11-04 2007-11-14 Ngk Insulators, Ltd. Microwave drying method
US20070295590A1 (en) * 2006-03-31 2007-12-27 Weinberg Jerry L Methods and systems for enhancing solid fuel properties
US20080136062A1 (en) * 2006-03-17 2008-06-12 Ibiden Co., Ltd. Drying apparatus, method for drying ceramic molded body, and method for manufacturing honeycomb structure
US20090038213A1 (en) * 2003-12-12 2009-02-12 Weinberg Jerry L Pre-burning, dry process methodology and systems for enhancing metallurgical solid fuel properties
US20090119981A1 (en) * 2006-03-31 2009-05-14 Drozd J Michael Methods and systems for briquetting solid fuel
US20090236333A1 (en) * 2006-02-21 2009-09-24 Rf Dynamics Ltd. Food preparation
US20090272028A1 (en) * 2006-03-31 2009-11-05 Drozd J Michael Methods and systems for processing solid fuel
US20090294440A1 (en) * 2008-05-30 2009-12-03 Paul Andreas Adrian System And Method For Drying Of Ceramic Greenware
US20110120991A1 (en) * 2009-11-25 2011-05-26 Jesus Humberto Armenta Pitsakis Methods For Drying Ceramic Materials
US20110168940A1 (en) * 2010-01-11 2011-07-14 National Applied Research Laboratories Composition for enhancing evaporation of solution and method thereof
US20130133220A1 (en) * 2011-11-29 2013-05-30 James Anthony Feldman Systems and methods for efficient microwave drying of extruded honeycomb structures
EP2637479A1 (en) * 2012-03-06 2013-09-11 Samsung Corning Precision Materials Co., Ltd. High frequency heating apparatus
CN104969018A (zh) * 2012-11-27 2015-10-07 康宁股份有限公司 陶瓷制品的自适应微波干燥的系统和方法
WO2016012334A1 (fr) * 2014-07-22 2016-01-28 Amb Systeme de traitement en continu de produits par apport thermique
CN106016986A (zh) * 2016-05-06 2016-10-12 电子科技大学 一种带金属反射板的褐煤干燥提质线
WO2019113429A1 (en) * 2017-12-08 2019-06-13 Alkar-Rapidpak, Inc. Ovens with metallic belts and microwave launch box assemblies for processing food products

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DE3778023D1 (de) * 1986-09-05 1992-05-07 Jiri Dokoupil Einrichtung zur waermebehandlung, insbesondere zum trocknen, von leder und dergl.
FR2661978A1 (fr) * 1990-05-14 1991-11-15 Marzat Claude Procede et dispositif de sechage rapide d'un materiau pouvant etre fragile par application de micro-ondes.
US5222544A (en) * 1991-08-12 1993-06-29 Ford Motor Company Bonding casting cores
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US3935060A (en) * 1973-10-25 1976-01-27 Mcdonnell Douglas Corporation Fibrous insulation and process for making the same
US4057702A (en) * 1973-10-31 1977-11-08 Automatisme & Technique Process and plant for the fritting of ceramic products
US4043380A (en) * 1973-11-28 1977-08-23 Valentine Match Plate Company Production of plaster molds by microwave treatment
US3953703A (en) * 1974-10-03 1976-04-27 Materials Research Corporation Method for drying ceramic tape
US4259560A (en) * 1977-09-21 1981-03-31 Rhodes George W Process for drying coal and other conductive materials using microwaves
US4210793A (en) * 1978-03-06 1980-07-01 Agence Nationale De Valorisation De La Recherche (Anvar) Microwave applicator for radiating microwaves to an elongated zone
US4176267A (en) * 1978-05-12 1979-11-27 Armstrong Cork Company Microwave energy trap
US4180918A (en) * 1978-10-06 1980-01-01 Caterpillar Tractor Co. Microwave drying of ceramic shell molds
EP0028267A1 (de) * 1979-10-05 1981-05-13 Heinrich Wagner Maschinenfabrik GmbH & Co Vorrichtung zur Trocknung von Giessereiformen und -kernen
US4772770A (en) * 1986-06-30 1988-09-20 Kabushiki Kaisha Toyota Chuo Kenkyusho Apparatus for joining ceramics by microwave
US4728531A (en) * 1986-11-04 1988-03-01 Ford Motor Company Method of drying refractory coated foam patterns
US4847460A (en) * 1987-04-02 1989-07-11 Leybold Aktiengesellschaft Apparatus for injecting microwave energy by means of an open microwave guide
US4896005A (en) * 1988-03-31 1990-01-23 Hermann Berstorff Maschinenbau Gmbh Method and apparatus for the continuous heating, pasteurization or sterilization of foodstuffs or the like by microwave energy
US5525783A (en) * 1993-05-07 1996-06-11 Tran Industrial Research Inc. Microwave heating device for lime and calcining
US5541390A (en) * 1995-03-20 1996-07-30 Cidelcem Industries Tunnel oven for microwave heating and cooking foods
US5911941A (en) * 1997-04-10 1999-06-15 Nucon Systems Process for the preparation of thick-walled ceramic products
WO2001049077A1 (en) * 1999-12-28 2001-07-05 Corning Incorporated Hybrid method for firing of ceramics
US6344634B2 (en) 1999-12-28 2002-02-05 Corning Incorporated Hybrid method for firing of ceramics
US6344635B2 (en) 1999-12-28 2002-02-05 Corning Incorporated Hybrid method for firing of ceramics
US7087874B2 (en) * 2002-11-19 2006-08-08 Denso Corporation Apparatus for drying ceramic molded articles using microwave energy
US20040104514A1 (en) * 2002-11-19 2004-06-03 Denso Corporation Method and apparatus for drying ceramic molded articles
US20040206755A1 (en) * 2003-04-18 2004-10-21 Hadinger Peter James Microwave heating using distributed semiconductor sources
EP1530015A3 (en) * 2003-11-04 2007-11-14 Ngk Insulators, Ltd. Microwave drying method
US8579998B2 (en) 2003-12-12 2013-11-12 Coaltek, Inc. Pre-burning, dry process methodology and systems for enhancing metallurgical solid fuel properties
EP2298852A3 (en) * 2003-12-12 2012-04-25 CoalTek, Inc. A pre-burning, dry process methodology and systems for enhancing solid fuel properties
US20090038213A1 (en) * 2003-12-12 2009-02-12 Weinberg Jerry L Pre-burning, dry process methodology and systems for enhancing metallurgical solid fuel properties
US20060086480A1 (en) * 2004-10-05 2006-04-27 Michael Kugelgen Method and system for producing a shell mould, in particular for investment casting
EP1645348A1 (de) * 2004-10-05 2006-04-12 MK Technology GmbH Verfahren und System zum Herstellen einer Schalenform insbesondere für das Feingießen
US20090236333A1 (en) * 2006-02-21 2009-09-24 Rf Dynamics Ltd. Food preparation
US10080264B2 (en) * 2006-02-21 2018-09-18 Goji Limited Food preparation
US20080136062A1 (en) * 2006-03-17 2008-06-12 Ibiden Co., Ltd. Drying apparatus, method for drying ceramic molded body, and method for manufacturing honeycomb structure
US20090272028A1 (en) * 2006-03-31 2009-11-05 Drozd J Michael Methods and systems for processing solid fuel
US8585786B2 (en) 2006-03-31 2013-11-19 Coaltek, Inc. Methods and systems for briquetting solid fuel
US8585788B2 (en) 2006-03-31 2013-11-19 Coaltek, Inc. Methods and systems for processing solid fuel
US20070295590A1 (en) * 2006-03-31 2007-12-27 Weinberg Jerry L Methods and systems for enhancing solid fuel properties
US20090119981A1 (en) * 2006-03-31 2009-05-14 Drozd J Michael Methods and systems for briquetting solid fuel
US9239188B2 (en) 2008-05-30 2016-01-19 Corning Incorporated System and method for drying of ceramic greenware
US20090294440A1 (en) * 2008-05-30 2009-12-03 Paul Andreas Adrian System And Method For Drying Of Ceramic Greenware
US20110120991A1 (en) * 2009-11-25 2011-05-26 Jesus Humberto Armenta Pitsakis Methods For Drying Ceramic Materials
US8481900B2 (en) * 2009-11-25 2013-07-09 Corning Incorporated Methods for drying ceramic materials
US8333018B2 (en) * 2010-01-11 2012-12-18 National Applied Research Laboratories Composition for enhancing evaporation of solution and method thereof
US20110168940A1 (en) * 2010-01-11 2011-07-14 National Applied Research Laboratories Composition for enhancing evaporation of solution and method thereof
US9038284B2 (en) * 2011-11-29 2015-05-26 Corning Incorporated Systems and methods for efficient microwave drying of extruded honeycomb structures
US20130133220A1 (en) * 2011-11-29 2013-05-30 James Anthony Feldman Systems and methods for efficient microwave drying of extruded honeycomb structures
US9335093B2 (en) 2011-11-29 2016-05-10 Corning Incorporated Systems and methods for efficient microwave drying of extruded honeycomb structures
EP2637479A1 (en) * 2012-03-06 2013-09-11 Samsung Corning Precision Materials Co., Ltd. High frequency heating apparatus
JP2013187194A (ja) * 2012-03-06 2013-09-19 Samsung Corning Precision Materials Co Ltd 高周波加熱装置
CN104969018B (zh) * 2012-11-27 2017-03-08 康宁股份有限公司 陶瓷制品的自适应微波干燥的系统和方法
CN104969018A (zh) * 2012-11-27 2015-10-07 康宁股份有限公司 陶瓷制品的自适应微波干燥的系统和方法
WO2016012334A1 (fr) * 2014-07-22 2016-01-28 Amb Systeme de traitement en continu de produits par apport thermique
US9943892B2 (en) 2014-07-22 2018-04-17 Amb System for the continuous treatment of products by thermal input
FR3024039A1 (fr) * 2014-07-22 2016-01-29 Amb Sa Systeme de traitement en continu de produits par apport thermique
CN106016986A (zh) * 2016-05-06 2016-10-12 电子科技大学 一种带金属反射板的褐煤干燥提质线
CN106016986B (zh) * 2016-05-06 2021-02-05 电子科技大学 一种带金属反射板的褐煤干燥提质线
WO2019113429A1 (en) * 2017-12-08 2019-06-13 Alkar-Rapidpak, Inc. Ovens with metallic belts and microwave launch box assemblies for processing food products
US11412584B2 (en) 2017-12-08 2022-08-09 Alkar-Rapidpak, Inc. Ovens with metallic belts and microwave launch box assemblies for processing food products
US11751296B2 (en) 2017-12-08 2023-09-05 Alkar-Rapidpak, Inc. Ovens with metallic belts and microwave launch box assemblies for processing food products

Also Published As

Publication number Publication date
GB1339644A (en) 1973-12-05
FR2076405A5 (ja) 1971-10-15
ES387205A1 (es) 1973-12-16
DE2101104A1 (de) 1971-07-22

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