SE123779C1

SE123779C1 -

Info

Publication number: SE123779C1
Authority: SE
Publication date: 1948-01-01

Description

Uppfinnare: J. Jonsson. Inventor: J. Jonsson.

Uppfinningens avser ett salt vid framstallning av s. k. harda plattor eller andra harda kroppar av en fibermasa, som erhalles genom defibrering av tra, t. ex. i form av traflis och vilken after tillsats av vatten och eventuellt ett bindemedel, I. ex. paraffin eller limamne, formas till en fuktig hopfiltad platta eller kropp. Sedan derma till vasentlig del befriais fran vatten utsattes den for pressning mellan pressplattor under fortgaende okning av tryckat pa fiberplattan till ett tryck av c:a 30 a 40 kg per cm', varefter fiberplattorna torkas genom upphettning av pre,ssplattorna. Darvid har hittills det namnda hoga trycket hihehallits i huvudsak oforandrat under he-la torkningsperioden, i .dat att de upphettade pressplattorna, allteftersom fiberplattan eller kroppen under torkningen krymper, successivt narmas till varandra. The invention relates to a salt in the production of so-called hard plates or other hard bodies of a fibrous pulp, which is obtained by defibration of wood, e.g. in the form of traflis and which after addition of water and possibly a binder, I. ex. paraffin or lime, formed into a moist felted plate or body. After it has been substantially released from water, it is subjected to pressing between press plates while continuously increasing the pressure on the fibreboard to a pressure of about 30 to 40 kg per cm 2, after which the fibreboards are dried by heating the press plates. In this case, the so-called high pressure has hitherto been maintained substantially unchanged during the entire drying period, in that the heated press plates, as the fiber plate or body shrinks during drying, are gradually approximated to each other.

Foreliggande uppfinning avser en forbattring .av namnda framstallningsmetod och kannetecknas i huvudsak darav, att presstrycket pa fiberplattan efter uppthende av del fdr framstallning av harda produkter erforderliga trycket av 30 a 40 kg per cm2 och innan plattan hardnat genom torkning tillates sjunka till ,ett tryck, som är vasentligt mind-re an namnda tryck och kan Tara lika stort som eller obetydligt storre an atmosfarstrycket, varvid pressplattornas upphettningsanordning praktiskt taget Wks overksam, till doss att fiberplattan hoppressats till den for den fardiga plattan avsedda tjockleken. Till fOljd av del salunda minskade trycket fa fibrerna en viss frihet att sammandraga eller forskjuta sig under torkningen, sä att uppkomsten av skadliga inre spanningar i den fardiga plattan forhindras, varigenom den fardiga produkten far st8rre elasticitet utan att hardheten i vasentlig grad minskas. Trycksankningen underlattar darjamte vattnets avgang ur plattan genom avdunstning, varigenom uppkomsten av ytdefekter forhindras, vilka elje,st vid uppratthallande av konstant tryck framkallas genom blasbildning mellan fiberplattan och pressplattan. Uppfinningen har darjamte den fordelen, att man som utgangs material kan anvanda en masse, som hell eller till vasentlig del bestar av relativt korta fibrer, vilket icke varit mojligt vid del kanda fOrfaringssattet. Det ãr viktigt att, till skillnad frau forut kanda och anvanda forfaranden, halla pressplattornas upphettningsanordning praktiskt taget overksam, till dess att fiberplattan hoppressats till den for den fardiga plattan avsedda tjockleken. The present invention relates to an improvement of said manufacturing method and is mainly characterized by the fact that the pressing pressure on the fibreboard after obtaining part for the production of hard products requires the pressure of 30 to 40 kg per cm 2 and before the board hardens by drying is allowed to drop to a pressure. which is substantially less than said pressure and can Tara as great as or insignificantly greater than atmospheric pressure, the heating device of the press plates being practically inactive Wks, to the extent that the fibreboard is compressed to the thickness intended for the finished plate. As a result, the pressure of the fibers decreased to a certain extent during the drying or shifting during drying, so that the formation of harmful internal stresses in the finished plate is prevented, whereby the finished product has greater elasticity without significantly reducing the hardness. The pressure drop also facilitates the exit of the water from the plate by evaporation, whereby the occurrence of surface defects is prevented, which, when maintaining a constant pressure, is induced by blistering between the fiber plate and the press plate. The invention furthermore has the advantage that a starting material can be used as a pulp which consists wholly or substantially of relatively short fibers, which has not been possible with the known method. It is important, in contrast to the prior art and methods used, to keep the heating device of the press plates practically inactive until the fibreboard is compressed to the thickness intended for the finished plate.

Ett fOrfarande enligt uppfinningen kan exempelvis utforas pa foljande salt. Utgangsmaterialet i form av traflis eller dylikt defibreras pa lampligt salt, exempelvis Indian roterande valsar under vattentillsats pa satt som angives i patentet nr 76 624, varefter massan sorteras till onskad finhetsgrad och koncentreras i Onskad grad samt forsattes med lampligt bindemedel, t. ex. hartslim eller annat limamne, paraffin eller dylikt i massabingar. Darefter tillfores massan en s. k. upptagningsmaskin med vira, dar vattenhalten ytterligare redueeras, dels medelst utsugning genom vakuum, dais medeIst pressvalsar. Efter behandlingen i upptagningsmaskinen far massan konsistensen av ett fuktigt hopfiltat fiberband, vilket avklippes i onskade langder, varvid erhalles s. k. vatark. Dessa placeras darefter pa platar, som inlaggas mellan pressplattorna i en hydraulisk press. Pressplattorna aro pa kant satt forsedda med genomborrade kanaler fOr Anga ,eller annat uppvarmningsmedium, sa att desamraa upphettas vid paslappning av anga. Den tillforda angan kan eventuellt hava overtryck och vara overhettad. Det är lampligt att inlagga en metalltradsduk, viraduk eller dylikt utmed atminstone den ena pressplattan i varje plattpar, I. ex. utmed undersidan av den ovre plat-tart, i andamal att astadkomma kanaler for vattnets utstromning under hoppressningen rasp. vattenangans avledning under torkningen. A process according to the invention can be carried out, for example, on the following salt. The starting material in the form of traflis or the like is defibrated on suitable salt, for example Indian rotating rollers under water addition in the manner set forth in patent No. 76 624, after which the pulp is sorted to the desired degree of fineness and concentrated to the desired degree and continued with suitable binder, e.g. resin glue or other glue substance, paraffin or the like in pulp bins. The pulp is then fed to a so-called wire pick-up machine, where the water content is further reduced, partly by means of suction by vacuum, i.e. by means of press rolls. After the treatment in the pick-up machine, the pulp has the consistency of a moist felted fiber strip, which is cut to desired lengths, whereby so-called water sheets are obtained. These are then placed on plates, which are inserted between the press plates in a hydraulic press. The press plates are provided on the edge with perforated channels for Anga, or another heating medium, so that they are heated when the steam is patched. The supplied steam may have overpressure and be overheated. It is convenient to insert a metal wire cloth, wire cloth or the like along at least one press plate in each pair of plates, I. e.g. along the underside of the upper plat-tart, in order to provide channels for the outflow of water during the compression rasp. water vapor diversion during drying.

Den hydrauliska pressen ãr forbunden riled en tryckpump, som pressar tryckvatskan, vanligen vatten, under Mgt tryck under den hydrauliska pressens presskolvar. Pumpen installes lampligen sã, att den astadkommer 2— — ett visst maximitryck pa pressplattorna. Da detta tryck uppnatts, avkopplas pumpen, 1ampligen automatiskt. Granstrycket fast:stalles genom farsOk pa sadant satt, att den .onskade tjockleken och hardhetsgraden hos den fardiga fiberplattan erhalles vid en viss Jnaterialmangd. Sedan den for den fardiga plattan avsedda tjockleken uppnatts genom hoppressning och vattnet salunda praktiskt taget utpressats, vilket, sfisom namnts, ger sig till kanna genom att det faststallda granstrycket uppnas och pumpen automatiskt avstanges, stanna plattorna i det uppnadda la-get. Darefter paslappes anga till pressplattorna, varvid torkning intrader, sa att aterstaende fuktighet bortgar. Genom pressens tryckminskning pa grund av fiberplattornas torkning och eventueIlt liven i ringa man pa grund av pressens eget tryckf all blir sluttrycket a 'den fardiga plattan avsevart mindre an del tryck, under vilket presspIattorna hoppres-sa den fuktiga plattan. I praktiken blir trycket vid torkningens slutskede ringa eller in-tet, kanske nagra fa kg per cm", under det begynnelsetrycket pa fiberplattan uppgar till 'c:a 30 A 40 kg per cm'. Vid slutad torkning har den hopfiltade plattan torkat till en fast, 'hard masa, vilken uttages och fardigstalles. -Vanligen lamnas pressplattorna oppna mel'tan vane pressningsprocedur, sa att de fa -svalna innan Mista pressning paborjas. The hydraulic press is connected to a pressure pump, which presses the pressure vessel, usually water, under high pressure under the pressure pistons of the hydraulic press. The pump is suitably installed so that it produces a certain maximum pressure on the press plates. When this pressure is reached, the pump is switched off, apparently automatically. The spruce pressure is fixed by cutting in such a way that the desired thickness and degree of hardness of the finished fibreboard is obtained at a certain amount of material. After the thickness intended for the finished slab has been reached by compression and the water has thus practically been squeezed out, which, as the name implies, manifests itself by the fixed spruce pressure being raised and the pump automatically shut off, the slabs remain in the obtained layer. Then apply the applicator to the press plates, with drying entering, so that the remaining moisture is removed. Due to the pressure reduction of the press due to the drying of the fibreboards and possibly the life of a small man due to the press' own pressure, the final pressure of the finished plate becomes considerably less than some pressure, below which the press plates are pressed the moist plate. In practice, the pressure at the final stage of drying becomes small or nothing, perhaps a few kg per cm ", while the initial pressure on the fibreboard amounts to 'about 30 A 40 kg per cm'. At the end of drying, the felted plate has dried to a solid, 'hard pulp, which is taken out and finished. -Usually the press plates are left open in the usual pressing procedure, so that the fa -cooled before Mista pressing is drilled.

Tryckets pa fiberplattorna fOrandringar Under pressningen och torkningen av s. h. liar'da fiberplattor enligt uppfinningen askad-liggores a bifogade ritning, som i diagram--form visar det i ett praktiskt fall uppmatta 'trycket pa fiberplattorna som funktion av 'presstiden. Diagrammet visar aven trycket 'hos den pressplattorna tillforda uppvarm. mngsangan i olika Ogonbliek. Fiberplattorna :hade vid inforandet i den hydrauliska pres- sen en vattenhalt av c:a 70First an- -bringades medelst en mindre presskolv ett 'tryck pa plattorna av c :a 9Vz kg per cm2 un- der en tid av c :aminut, varvid stOrre de- len av vattnet avpressades. Darefter inkopp- lades en storre presscylinder, varvid i sam-band med omkopplinden trycket pa fiberplattorna sjiink till c:a 3 kg per ce, vilket tryck -uppmattes c:a I minut efter pressningens borjan. Medelst den stora presskolven hop'pressades sâ plattorna till den Onskade tjock-leken, i ifragavarande fall 4 mm, varvid trycket pa fiberplattorna steg till ett maximum av -32 kg per cm'. Namnda maximitryck uppnad:des efter forloppet av drygt 3 minuter fran pressningens bOrjan. SA snart onskad tjocklek hos fiberplattorna ernatts, fastlastes pres' sen i installt lage. Omedelbart fore fastlasningen av pressen paslapptes upphettnings-angan och ett ogonblick senare hade varmet 'Iran denna fortplantats till pressplattornas I ber5ring med fiberplattorna varande ytor. Angtrycket och darmed torkningstemperaturen stegrades sã smaningom under torkningens gang for att uppna ett maximum av c:a 472 kg per cm' efter forloppet av ungefar 10 minuter. Efter ytterligare 15 minuter voro fiberplattorna fardigtorkade, varf5r angtill7 forseln avbrots. Pa grund av den -pnom angtorkningen orsakade avdunstningen av vatten frilm fiberplattorna avensom pa grund av en langsamt fortgaende utpressning av vatteu under inverkan av det radande presstrycket sjonk presstrycket pa fiberplattorna sa smaningom efter den ovan namnda fastlasningen .av pressplattorna. Redan efter en minut hade salunda trycket sjunkit fran 32 kg per cm' till 25 kg per cm', och under de sista 7 minuterna av pressningen uppgick trycket blott till ungefar 3 kg per cm'. Sasom av diagrammet framgar, tog hela pressningen 27 minuter i ansprak, raknat Iran det ogonblick, dd plattorna infordes i pressen, till det ogonblick, da de voro fardiga att uttagas ur densamma. Changes in the pressure on the fibreboards During the pressing and drying of so-called fibreboards according to the invention, the accompanying drawing is shown in diagrammatic form, which in a practical case shows the pressure applied to the fibreboards as a function of the pressing time. The diagram also shows the pressure 'of the press plates supplying heat. mngsangan in different Ogonbliek. The fibreboards: when introduced into the hydraulic press had a water content of about 70First, a pressure was applied by means of a smaller press piston to the plates of about 9Vz kg per cm2 for a time of c: aminute, whereby A large part of the water was squeezed out. Then a larger press cylinder was connected, whereby in connection with the switching reel the pressure on the fiber plates dropped to about 3 kg per ce, which pressure was measured about one minute after the start of the pressing. By means of the large press piston, the plates were compressed to the desired thickness, in this case 4 mm, whereby the pressure on the fiber plates rose to a maximum of -32 kg per cm '. The said maximum pressure was reached after just over 3 minutes from the beginning of the pressing. As soon as the desired thickness of the fibreboards is reached, the pressure is fixed in the installed layer. Immediately before the welding of the press, the heating element was released and a moment later the heat had propagated to the surfaces of the press plates in contact with the fiber plates. The steam pressure and thus the drying temperature was gradually increased during the drying process to reach a maximum of about 472 kg per cm 2 after the course of about 10 minutes. After a further 15 minutes, the fibreboards were completely dried, whereupon the transport was interrupted. Due to the steam drying caused by the evaporation of water from the fibreboards, also due to a slow continuous squeezing of water under the influence of the radiating press pressure, the press pressure on the fibreboards gradually decreased after the above-mentioned welding of the press plates. Already after one minute the salunda pressure had dropped from 32 kg per cm 'to 25 kg per cm', and during the last 7 minutes of pressing the pressure amounted to only about 3 kg per cm '. As the diagram shows, the entire pressing took 27 minutes, Iran shaved the moment the plates were inserted into the press, until the moment when they were ready to be taken out of it.

Claims

Patent claim:

1. -1. Set in the production of so-called hard plates or other hard bodies of a fibrous mass, which is obtained by defibration of tra, e.g. in the form of traflis, and which after the addition of water and possibly a binder, e.g. paraffin or glue substance, is formed into a damp felted plate or the like, which, having been substantially freed from the water, was subjected to pressing between press plates and dried by heating the press plates, characterized in that the pressing pressure on the fibreboard, after obtaining the pressure required for hard products is 30 to 40 kg per cm 2 and before the plate has hardened by drying, it is allowed to sink to a pressure which is substantially less than said pressure and can be as large as or slightly greater than atmospheric pressure, whereby the heating plates of the press plates practically Hiles inactive until the fiberboard is compressed to the thickness intended for the finished board.

2. Used in the manufacture of fibreboards or the like according to claim 1 - using a hydraulic press, characterized in that the pressure reduction of the fibreboard or body is effected by the hydraulic pump being disconnected, suitably automatically, upon attainment of the predetermined maximum pressure, whereby a progressive pressure reduction is obtained on. due to shrinkage occurring during drying of the fibreboard and possibly also due to: pressure drop in the press due to leakage losses. Stockholm 1948. Kungl. Boktr, B. A. Norstedt & Sinter 480080