WO1993002842A1 - Procede, autoclave et appareil a autoclave pour le chauffage d'objets en bois devant être aboutes - Google Patents

Procede, autoclave et appareil a autoclave pour le chauffage d'objets en bois devant être aboutes Download PDF

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Publication number
WO1993002842A1
WO1993002842A1 PCT/DK1992/000238 DK9200238W WO9302842A1 WO 1993002842 A1 WO1993002842 A1 WO 1993002842A1 DK 9200238 W DK9200238 W DK 9200238W WO 9302842 A1 WO9302842 A1 WO 9302842A1
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WO
WIPO (PCT)
Prior art keywords
autoclave
objects
section
heated
bent
Prior art date
Application number
PCT/DK1992/000238
Other languages
English (en)
Inventor
Ib Obel Pedersen
Original Assignee
Ib Obel Pedersen
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ib Obel Pedersen filed Critical Ib Obel Pedersen
Publication of WO1993002842A1 publication Critical patent/WO1993002842A1/fr

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Classifications

    • 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
    • H05B6/46—Dielectric heating
    • H05B6/54—Electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27H—BENDING WOOD OR SIMILAR MATERIAL; COOPERAGE; MAKING WHEELS FROM WOOD OR SIMILAR MATERIAL
    • B27H1/00—Bending wood stock, e.g. boards
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B27K5/003—Treating of wood not provided for in groups B27K1/00, B27K3/00 by using electromagnetic radiation or mechanical waves
    • B27K5/0055—Radio-waves, e.g. microwaves
    • 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
    • F26B3/343—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 in combination with convection
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B7/00—Drying solid materials or objects by processes using a combination of processes not covered by a single one of groups F26B3/00 and F26B5/00

Definitions

  • the present invention relates to a method of the type stated in the preamble to claim 1 as well as an autoclave and an apparatus for heating wooden objects to be butted in connection with solid bending of such wooden objects, e.g. when manufacturing furniture, by which method the objects are treated by means of heat and steam for a predetermined period of time before they are bent and/or moulded in the desired shape.
  • Solid bending of wood is a well known process used when shaping i.a. objects for the manufacture of furniture. Solidbending is e.g. usedwhenmanufacturingthe so-called bent-wood chair.
  • wood are useable for solid bending as the structure of the wood has to meet certain requirements in order for it to be applicable for this process.
  • One of the best and most frequently used types of wood for this purpose is beech, but a large number of other types of wood such as birch, ash, rubber tree, teak a.o. may also be used for solid bending.
  • solid bending of wood traditionally takes place by heating the objects in an autoclave by means of steam and moistening them if required. This heating process may take up to several hours.
  • said objects are taken out of the autoclave and bent and moulded in the desired shape in a special press whichusually bends the wood over a form by means of a bending strap, whereupon the object is held in the bent shape by nailing a board or the like to the ends of the object in order to hold it in the bent shape after having removed it from the press.
  • the method is encumbered with the drawback that the wood is weakened to some extent, thereby having less strength intariat construction also outsidethe sections actually to be bent, which limits the applicability especially for load-bearing constructions, such as chairs.
  • selective heating may be obtained in a very simple manner by means of HF heating. It is, however, already known to use HF heating in some processes for the treatment of wooden products.
  • Swedish printed accepted application No. 423,931 thus discloses a method of drying wooden products, where the drying is effected by arranging the products in a closed drying chamber where they are exposed to a microwave field from one or more microwave generators.
  • the air in the chamber is adjusted as to temperature and moisture to allow the drying to take place by the moisture of the products being made to migrate from the middle of the products towards the boundary surfaces. This implies that the temperature of the air must be kept at a lower value than the temperature of the products and that from the start the humidity of the air should be kept at such a high value that the drying of the surface layers of the products which might impede the migration of the moisture is prevented.
  • a method of the type described inthe introduction is suggested, saidmethodbeing charac ⁇ terised in that the electrode members are placed in such a manner that the high frequency capacitive field is arranged across the object(s) substantially onlv in the section(s) oftheobjec (s) which areto bebutted, whereby only the section later to be bent is heated while the rest of the wooden object(s) is/are not heated.
  • the wood to be heated is heated and even faster than hitherto known at that. Energy is saved, as only the wood to be heated is subjected to the heatingprocess and the undesired side effects of the heating process are avoided, that is the weakening of the sections which do not need to be heated and which therefore keep their strength by the method according to the invention.
  • the invention further relates to an autoclave and an apparatus for carrying out the method according to the invention and the autoclave is characterised in that it is made of an electrically non-conductive material with small or substantially no dielectric losses and provided with holding means for the mounting of a number of ex ⁇ changeable electrodeplates above andbelow or on each side of the autoclave.
  • An autoclave to be used when carrying out the method according to the invention may furthermore be characterised in that it is provided with a number of firmly mounted or displaceable electrodeplates situated opposite each other inside or on the outside of the autoclave, said plates each optionally being connectable to an HF generator.
  • Fig. 1 shows an example of an autoclave adapted for carrying out the method according to the invention
  • Fig. 2 is a sectional view of an example of an embodiment of an autoclave for carrying out the method according to the invention
  • Fig. 3 is a sectional view of an example as in Fig. 2 but with the electrodes being placed differently,
  • Fig. 4 is a sectional view through a second example of an embodiment of an autoclave for carrying out the method according to the invention
  • Fig. 5 is an oblique plan view of an example of a row of electrode plates
  • Fig. 6 is an oblique plan view of the example of Fig. 5 when said electrode plates are pushed together.
  • Figs. 1, 2 and 3 show an example of an apparatus to be used when carrying out the invention.
  • the heating may therefore advantageously take place in an autoclave 10, where temperature and moisture may be controlled and adjusted.
  • the wooden objects 12 later to be bent are placed on supports 14 in the autoclave 10 and arranged in such a manner relative to each other that all the sections to be heated are substantially in a "column” above each other and/or in a “row” next to each other.
  • the entire "column” or “row” of bending sections may be heated simultaneously by placing an HF electrode at each end of the "column” or “row” and applying an HF field over the bending sections while the rest of thewood is not affected by the HF field.
  • the autoclave 10 is preferably made of a material with small dielectric losses, e.g. a thermostable plastic material. The same applies to the supports 14.
  • thermostable plastics By manufacturing the autoclave in a material with small dielectric losses, such as thermostable plastics, it is possible to heat the wood inside the autoclave by applying an HF field through HF electrodes placed on the outside of the container wall in simple fixtures.
  • the advantage of placing the electrodes on the outside of the autoclave is that it is thereby made easier to change the position of the electrodes.
  • the electrodes 20-23 may be positioned differently.
  • the positioning of the electrodes is of course selected in such a manner that the HF field 36 passes through exactly the sections 50 of the wood to be bent.
  • the electrode plates may advantageously be manufactured in the form of more small plates 20-32, said plates being somewhat narrower but in the full width of the autoclave and adapted to be mounted preferably displaceably in continuation of each other in more optionally overlapping electrode sections.
  • the electrodes may thereby quickly be adjusted to heat exactly the sections desired to be bent.
  • the electrodes 20-32 may be fastened to holders mounted independently of the autoclave.
  • electrode holders 40 have been provided on the autoclave per se.
  • the holders 40 are preferably manufactured in a thermostable, substantially non-loss insulating material in order not to affect the electric field 36.
  • the holders may be shaped in many different ways.
  • two longitudinal carrying rails 40 have been provided above and below the autoclave, a number of rectangular electrode plates 20-33 being dis- placeable on said carrying rails in the longitudinal direction ofthe autoclave and optionallybeingpushedmore or less together or being stacked, as shown in Fig. 6.
  • a HF generator 16 is connected to at least two of the electrode plates 21, 22, 23, 24 - 33, which only are of the extension necessary to heat the sections of the objects desired to be bent.
  • the electrodes are made of metal (aluminium, brass, copper) in the form of thin plates having a length and a width covering the section to be treated, it is simple and inexpensive to carry out selec ⁇ tive heating and as a consequence of the HF energy simul ⁇ taneously heating the objects all over their entire cross section, said heating may take place in a few minutes in contrast to conventional heating by means of steam which often takes hours.
  • Autoclaves may be used for HF heating.
  • the drawing shows an autoclave 10 with a pivoting cover 18 at ⁇ one end which is merely shown as an example. Autoclaves which are opened in another manner, e.g. where the upper portion may be tipped up, may also be used.
  • the autoclave may also have a rectangular or quadratic cross section, which configuations, relative to their sectional areas, may contain more objects than autoclaves with, a circular cross section.
  • the autoclave is provided with a safetyblow-off valve 34, preferably a valve with a little aperture, in order to prevent desiccation.
  • valve 34 opens when the pressure rises slightly above the atmospheric pressure whereby no special requirements are made to the pressure resistance of the autoclave.
  • the HF electrodes may be placed inside the autoclave as indicated in Fig. 4 and carry the HF supply lines 42, 44 through the wall of the autoclave in gastight lead-ins 35. If the electrodes are mounted on the inside, the autoclave may be constructed of both plastics and metal.
  • the HF electrodes may be divided into a suitably large number, e.g. as shown 2 x 7 sections firmly mounted and which may optionally be connected to the generator, whereby the extension of the HF field applied depends on which elec ⁇ trode members are connected to the HF generator.
  • the electrode members 24, 26, 28 are interconnected and connected to one generator terminal (not shown) via the HF supply line 42 and the electrode members 25, 27, 29 are also interconnected and connected to the second generator (not shown) via the HF supply line 44.
  • the middle section 50 of the wooden object is heated.
  • the autoclave is preferably provided with sensors to measure temperature, moisture and possible pressure. Such sensors may be positioned in many places and they are not indicated on the drawing.
  • the electrodes 20-33 are positioned above and below the wooden objects. This position is only chosen by way of example.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Forests & Forestry (AREA)
  • Electromagnetism (AREA)
  • Wood Science & Technology (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Microbiology (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Biotechnology (AREA)
  • Molecular Biology (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

Procédé pour le chauffage d'objects en bois devant être aboutés en relation avec le pliage monobloc de tels objects, par example lors de la fabrication de mobilier. Dans le pliage monobloc, les objets sont traités à la chaleur et la vapeur pendant un temps déterminé avant d'être pliés et/ou moulés à la forme désirée. Selon l'invention, un ou plusieurs systèmes d'électrodes (20, 21) sont disposés de manière à être connectés à un générateur HF (16) de sorte qu'un champ de tension HF traverse l'objet (12) dans la zone (50) - et sensiblement seulement la zone - de l'objet devant être abouté; ainsi, ladite zone et seulement cette zone devant être aboutée, est chauffée, pendant que le reste de l'objet en bois (12) n'est pas chauffé. Les avantages suivants sont ainsi obtenus: seule la zone (50) de l'objet en bois à plier est chauffée et plus vite que par les procédés connus. De l'énergie est économisée et les effets secondaires nuisibles du procédé de chauffage sont évités, c'est-à-dire un affaiblissement des zones qui ne nécessitent pas de chauffage.
PCT/DK1992/000238 1991-08-05 1992-08-04 Procede, autoclave et appareil a autoclave pour le chauffage d'objets en bois devant être aboutes WO1993002842A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK143191A DK143191A (da) 1991-08-05 1991-08-05 Fremgangsmaade, autoklave og anlaeg med autoklave til opvarmning af emner af trae, som skal stukkes
DK1431/91 1991-08-05

Publications (1)

Publication Number Publication Date
WO1993002842A1 true WO1993002842A1 (fr) 1993-02-18

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PCT/DK1992/000238 WO1993002842A1 (fr) 1991-08-05 1992-08-04 Procede, autoclave et appareil a autoclave pour le chauffage d'objets en bois devant être aboutes

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AU (1) AU2466492A (fr)
DK (1) DK143191A (fr)
WO (1) WO1993002842A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT405036B (de) * 1995-03-22 1999-04-26 Berger Johann Verfahren und anlage zur herstellung von neuem längsholz-, insbesondere leisten- und/oder stabmaterial
FR2770441A1 (fr) * 1997-10-30 1999-05-07 Bernard Dedieu Procede de sechage des bois de sciage et dispositif permettant la mise en oeuvre du procede
US5955023A (en) * 1996-11-27 1999-09-21 Callutech, Llc Method of forming composite particle products
FR2781710A1 (fr) * 1999-09-28 2000-02-04 Valeurs Bois Ind Procede de sechage des bois de sciage et dispositif permettant la mise en oeuvre du procede
FR2793008A1 (fr) * 1999-04-30 2000-11-03 Valeurs Bois Ind Procede d'extraction de jus naturel de matieres vegetales ligneuses, dispositif permettant la mise en oeuvre du procede et utilisation du procede pour la production de vegetaux ligneux seches
US6675495B2 (en) 1997-10-30 2004-01-13 Valeurs Bois Industrie Method for drying saw timber and device for implementing said method
EP1399700A1 (fr) * 2001-06-27 2004-03-24 The University Of Melbourne Procede de traitement de bois aux micro-ondes
RU2495418C2 (ru) * 2011-12-28 2013-10-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования Марийский государственный технический университет Способ измерения комля древесного растения
RU2623043C1 (ru) * 2016-06-03 2017-06-21 Виктор Кузьмич Сухов Способ термообработки древесины и установка для его осуществления

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1994607A (en) * 1933-01-28 1935-03-19 Peter C Reilly Electrothermic process of shaping wood
CH213095A (de) * 1938-09-10 1941-01-15 Beuken Clemens Louis Ing Dr Verfahren zum Biegen von Stöcken aus Holz in erhitztem Zustand und Vorrichtung zur Ausübung dieses Verfahrens.
US2231457A (en) * 1936-08-03 1941-02-11 John L Stephen Electrical apparatus
DE848861C (de) * 1951-03-08 1952-09-08 Fassfabrik Diener & Roth Verfahren zum Biegen von Holz
DE3106304A1 (de) * 1980-02-21 1982-02-18 Reinhard Ing.(grad.) 8643 Küps Tröbs Plastifizierung und trocknung von holz und holzwerkstoffen fuer die herstellung gebogener teile
DE3033802A1 (de) * 1980-09-09 1982-04-22 Kenji Toyonaka Osaka Hasegawa Verfahren zur plastischen biegeverformung von holzwerkstuecken und vorrichtung dazu
DE3406715A1 (de) * 1984-02-24 1985-08-29 Manfred Dipl.-Ing. Kreidl (FH), 8729 Steinsfeld Verfahren zur plastifizierung von vollholz und holzwerkstoffen in einem plastifizierzylinder

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1994607A (en) * 1933-01-28 1935-03-19 Peter C Reilly Electrothermic process of shaping wood
US2231457A (en) * 1936-08-03 1941-02-11 John L Stephen Electrical apparatus
CH213095A (de) * 1938-09-10 1941-01-15 Beuken Clemens Louis Ing Dr Verfahren zum Biegen von Stöcken aus Holz in erhitztem Zustand und Vorrichtung zur Ausübung dieses Verfahrens.
DE848861C (de) * 1951-03-08 1952-09-08 Fassfabrik Diener & Roth Verfahren zum Biegen von Holz
DE3106304A1 (de) * 1980-02-21 1982-02-18 Reinhard Ing.(grad.) 8643 Küps Tröbs Plastifizierung und trocknung von holz und holzwerkstoffen fuer die herstellung gebogener teile
DE3033802A1 (de) * 1980-09-09 1982-04-22 Kenji Toyonaka Osaka Hasegawa Verfahren zur plastischen biegeverformung von holzwerkstuecken und vorrichtung dazu
DE3406715A1 (de) * 1984-02-24 1985-08-29 Manfred Dipl.-Ing. Kreidl (FH), 8729 Steinsfeld Verfahren zur plastifizierung von vollholz und holzwerkstoffen in einem plastifizierzylinder

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT405036B (de) * 1995-03-22 1999-04-26 Berger Johann Verfahren und anlage zur herstellung von neuem längsholz-, insbesondere leisten- und/oder stabmaterial
US5955023A (en) * 1996-11-27 1999-09-21 Callutech, Llc Method of forming composite particle products
EP1248059A1 (fr) * 1997-10-30 2002-10-09 Valeurs Bois Industrie Procédé de séchage des bois de sciage et dispositif permettant la mise en oeuvre du procédé
FR2770441A1 (fr) * 1997-10-30 1999-05-07 Bernard Dedieu Procede de sechage des bois de sciage et dispositif permettant la mise en oeuvre du procede
WO1999023429A1 (fr) * 1997-10-30 1999-05-14 Valeur Bois Industrie Procede de sechage des bois de sciage et dispositif permettant la mise en oeuvre du procede
US6675495B2 (en) 1997-10-30 2004-01-13 Valeurs Bois Industrie Method for drying saw timber and device for implementing said method
US6473994B1 (en) 1997-10-30 2002-11-05 Valeurs Bois Industrie Method for drying saw timber and device for implementing said method
WO2000066960A1 (fr) * 1999-04-30 2000-11-09 Valeurs Bois Industrie Procede d'extraction de jus naturel de matieres vegetales ligneuses, dispositif permettant la mise en oeuvre du procede et utilisation du procede pour la production de vegetaux ligneux seches, ou de jus
FR2793008A1 (fr) * 1999-04-30 2000-11-03 Valeurs Bois Ind Procede d'extraction de jus naturel de matieres vegetales ligneuses, dispositif permettant la mise en oeuvre du procede et utilisation du procede pour la production de vegetaux ligneux seches
US6581299B1 (en) * 1999-04-30 2003-06-24 Valeurs Bois Industrie Method for extracting natural juice of ligneous plant material, device for carrying out said method and use of said method in the production of dried ligneous plants material
FR2781710A1 (fr) * 1999-09-28 2000-02-04 Valeurs Bois Ind Procede de sechage des bois de sciage et dispositif permettant la mise en oeuvre du procede
EP1399700A1 (fr) * 2001-06-27 2004-03-24 The University Of Melbourne Procede de traitement de bois aux micro-ondes
EP1399700A4 (fr) * 2001-06-27 2009-08-19 Univ Melbourne Procede de traitement de bois aux micro-ondes
RU2495418C2 (ru) * 2011-12-28 2013-10-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования Марийский государственный технический университет Способ измерения комля древесного растения
RU2623043C1 (ru) * 2016-06-03 2017-06-21 Виктор Кузьмич Сухов Способ термообработки древесины и установка для его осуществления

Also Published As

Publication number Publication date
DK143191A (da) 1993-02-06
DK143191D0 (da) 1991-08-05
AU2466492A (en) 1993-03-02

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