SE176815C1 - - Google Patents

Description

Uppfinnare: 0 Karsten, P Agren och B Nilsson Foreliggande uppfinning avser ett salt att astadkomma en gastat forbindning mellan en metallisk genomforingsbult och en denna omgivande isolering. Inventors: 0 Karsten, P Agren and B Nilsson The present invention relates to a salt for providing a gaseous connection between a metallic bushing bolt and an insulation surrounding it.

Det ãr kant att astadkomma en med en omgivande isolering forsedd genomfOringsbull, i vilken forbindelsen mellan isoleringen och genomforingsbulten ar olje- och gastat, pa sa satt att genomforingsbulten omgjutes med en fullstandigt polymeriserbar plast. Ddrvid placeras genomforingsbulten i en gjutform. Sedan plasten hallts i gjntformen och darvid bringats att omge bulten, underkastas plasten en hardning. Om bulten och den omgivande plasten ha varmeutvidgningsokeffieienter, som skilja sig mycket fran varandra kan det t. ex. vid plotslig stark uppvarmning av genomforingsbulten, nagot som exempelvis kan f5rekomma vid kortslutning av genomf5ringsbulten, intraff a att otatheter upptrada mellan bulten och dess isolering. I syfte alt undvika att dylika av varmespanningar fororsakade otatheter upptrada har man foreslagit att i gransytan mellan genomforingsbulten och den omgivande plasten anbringa ett tunt lager av slappmedel. Detta lager stracker sig inte utefter hela gransytan utan ett mindre parti runt bultens yta Or fritt frail slappmedel. Darigenom uppnas att plasten och bulten bortsett fran i det parti, dar slappmedel saknas, vid varmevdxlingar karma rant sig i forhallande till varandra, sá att risken for uppkomsten av otatheter pa grand av varmespanningar blir mindre. Emellertid forekommer fortfarande risk for att catheter skola uppstâ i det omrade av gransytan dar plasten och bulten aro bundna vid varandra. Sarskilt Or detta fallet vid starka temperaturvaxlingar och efter langre tids drift, cla risk kan foreligga att forbindningen mellan plasten och bulten slapper. En annan naekdel hos de beskrivna isolerade genomforingsbal tarna Or att deras framstallning innebar problem med hansyn till den risk for sprickbildning som fOreligger pa grand av att plasterna krympa cla de overforas fran ohardat till hardat tillstand. Sprickbildning kan inte bara f0- rekomma just i saraband med sjalva tillverkningen utan Oven efter en tids drift. De inre sp5.nningarna, som alstras i plasten ph grund av krympningen vid hardningen, kunna namligen ge sig till karma pa detta salt forst efter det den isolerade genomforingsbulten utsatts fOr pakanningar. Sarskilt .stora problem i det behandlade avseendet foreligga- cm genomforingsbulten har en i forhallande till isoleringens godstjoeklek stor diameter. Om den gas, mot vilken forbindningen ,skall vara tat, be-star av mycket sma molekyler, sasom fallet Or for vatgas, Or tathetsproblemen sarskilt svara .att bemastra pa grund av sadana gasers formaga att passera genom de minsta sprickor eller mellanrum. It is possible to provide a bushing provided with a surrounding insulation, in which the connection between the insulation and the bushing bolt is oil and gas, in such a way that the bushing bolt is encapsulated with a completely polymerizable plastic. In this case, the bushing bolt is placed in a mold. After the plastic has been held in the mold and thereby brought around the bolt, the plastic is subjected to a hardening. If the bolt and the surrounding plastic have heat expansion coefficients, which differ greatly from each other, it can e.g. in the event of a sudden strong heating of the bushing bolt, something which may occur, for example, in the event of a short circuit of the bushing bolt, in the event that malfunctions occur between the bolt and its insulation. In order to prevent the occurrence of such impurities caused by thermal stresses, it has been proposed to apply a thin layer of slack in the spruce surface between the bushing bolt and the surrounding plastic. This layer does not extend along the entire spruce surface but a small portion around the surface of the bolt Or free frail slack. In this way it is achieved that the plastic and the bolt, apart from the part where there is no slack agent, during heat exchanges karma ran in relation to each other, so that the risk of the occurrence of inertia due to thermal stresses is reduced. However, there is still a risk that catheters will arise in the area of the spruce surface where the plastic and the bolt are bonded together. In particular in the case of strong temperature fluctuations and after prolonged operation, there may be a risk that the connection between the plastic and the bolt will loosen. Another key part of the described insulated bushes The fact is that their production posed problems with regard to the risk of cracking which exists due to the fact that the plastics shrink and are transferred from uncured to hardened condition. Cracking can not only occur precisely in saraband with the actual manufacturing but also after a period of operation. Namely, the internal stresses which are generated in the plastic due to the shrinkage during curing can give rise to karma on this salt only after the insulated bushing bolt has been subjected to packing jugs. Particularly large problems exist in the treated respect and the lead-through bolt has a large diameter in relation to the material thickness of the insulation. If the gas to which the compound is to be made consists of very small molecules, as in the case of hydrogen gas, the problems of tightness are particularly difficult to master due to the ability of such gases to pass through the smallest cracks or gaps.

Ett annat forhallande som maste beaktas Or att de isolerade genomforingsbultarna kunna utsattas for stora mekaniska pakanningar. En isolering bestaende av en oarmerad plast kan darfor understundom aga en otillfredsstallande mekanisk hallfasthet. Another aspect that must be taken into account is that the insulated bushing bolts can be exposed to large mechanical seals. An insulation consisting of an unreinforced plastic can therefore sometimes cause an unsatisfactory mechanical half-strength.

F6r att undvika att en av krympningen orsakad sprickbildning upptrader i en plast och for att Oka den mekaniska hallfastheten hos plaster ai det kant att forsatta den med ett armeringsmaterial. Nar det galler fullstandigt polymeriserbara plaster, sasom t. ex. omattade polyesterplaster och epoxiplaster, anvandas konventionellt glasfiberprodukter som armeringsmaterial. Det har emellertid visat sig, att isolerade genomforingsbultar, vilka framstains genom anbringande av de namnda plasterna och en arnnering bestaende av en glasvax runt bultarna med efterfoljande hardning av plasten, ge forbindningar, vilka uppvisa otatheter antingen redan fran borjan eller ef- 2— — ter en tid, sedan de utsatts f5r termiska pakanningar. To prevent cracking caused by the shrinkage from occurring in a plastic and to increase the mechanical inertness of plastics at the edge of continuing it with a reinforcing material. When it comes to completely polymerizable plastics, such as e.g. unsaturated polyester plastics and epoxy plastics, fiberglass products are conventionally used as reinforcement materials. It has been found, however, that insulated lead-through bolts, which are formed by applying the said plastics and a decoration consisting of a glass wax around the bolts with subsequent hardening of the plastic, give connections which show inaccuracies either already from the beginning or after 2— - for a time, after being subjected to thermal packing.

Enligt foreliggande uppfinning undvikas nackdelarna hos tidigare namnda isolerade genomforingsbultar och erhalles en. forbindining mellan bulten och isoleringen, som fir helt gastat, aven sedan bulten under lang tid utsatts for temperaturer Over 100° C och upprepade ganger underkastats hastiga temperaturvaxlingar mellan temperaturer Over 100° C och rumstemperatur. According to the present invention, the disadvantages of the aforementioned insulated bushing bolts are avoided and one is obtained. connection between the bolt and the insulation, which is completely gassed, even after the bolt has been exposed to temperatures above 100 ° C for a long time and has repeatedly been subjected to rapid temperature fluctuations between temperatures above 100 ° C and room temperature.

Enligt uppfinningen astadkommes den gastata forbindningen mellan genomforingsbulten och dess omgivande isolering som innefattar en fullstandigt polymeriserbar plast pa sâ salt att den fullstandigt polymeriserbara plasten och ett av syntetiska organiska fibrer uppbyggt armeringsmaterial for plasten anbringas omkring genomfOringsbulten, varefter plasten Overfores i hardat tillstand. According to the invention, the gas-tight connection between the bushing bolt and its surrounding insulation is provided which comprises a fully polymerizable plastic on such salt that the fully polymerizable plastic and a synthetic organic fiber reinforcing material for the plastic are applied around the bushing bolt, after which the plastic is transferred in the hardened state.

Understundom kan det vara lampligt att, innan plasten och armeringsmaterialet anbringas, applicera ett tunt skikt av ett elastiskt material, hi. a. silikongummi, pa bultens yta. Ett tunt silikongummiskikt kan exempelvis erhallas genom Waring av silikongummipasta (t. ex. »Silastic Adhesive 2007» Iran DOW Corning Corp. USA) pa bulten. Sometimes, before applying the plastic and reinforcement material, it may be appropriate to apply a thin layer of an elastic material, hi. a. silicone rubber, pa bultens yta. A thin silicone rubber layer can be obtained, for example, by Waring of silicone rubber paste (eg »Silastic Adhesive 2007» Iran DOW Corning Corp. USA) on the bolt.

Sam exempel pa lampliga fullstandigt polymeriserbara plaster kunna namnas omattade polyesterplaster och epoxiplaster. Dessa plaster bruka ofta benamnas losningsmedelsfria plaster. En utmarkande egenskap has dem Or att de harda utan avspaltning av flyktiga bestandsdelar. I begransad utstraekning kunna de fOr andamalet enligt uppfinningen forsattas med pulver- eller kornformiga fyllmedel sasam kvartsmjol, glimmermjol etc. Som exempel pa anvandbara organiska fibrer for armeringsmaterialet kunna namnas polyetentereftalatfibrer (»Terylen», »Dacron»), polyvinylidenkloridfibrer (»Saran»), polyakrylnitrilfibrer (»Orlon»), polyamidfibrer (»Nylon», »PerIon») och liknande fibrer, vilka vanligen framstallas genom dragning ur en smalta eller en losning. Dylika fibrer aga den egenskapen att de vid uppvarmning till en: temperatur, vid vilken molykylerna kunna rora sig ur deras vid tillverkningen erhallna strackta tillstand, underga en krympning. Armeringsmaterialet kan. med fordel ha formen av en vav, ett vavt band, eller ett garn som lindas omkring genomforingsbulten lampligen med nagon atdragning. Plasten kan tillf6ras pa olika satt. Man kan t. ex. tillfora plasten genom att impregnera armeringsmaterialet med den, innan armeringsmaterialet anbringas pa bulten. Man kan ocksa. anhringa plasten samtidigt med eller i anslutning till att armeringsmaterialet lindas om bulten t. ex. genom att vane palindat vary av fibermaterialet bestrykes med plast innan Riljande vary paThres. Pet Or ()ask mojligt att f5rst anbringa fibermaterialet och att darefter tillfora plas ten genom en impregneringsproeess, med eller utan. anvandning av vakuum. Enligt en mycket fordelaktig utforingsform av uppfinningen bestar de organiska fibrerna av polyetentereftalat och den fullstandigt polymeriserbara plasten av ett epoxiharts. Examples of suitable fully polymerizable plastics are unsaturated polyester plastics and epoxy plastics. These plastics are often referred to as solvent-free plastics. A distinguishing feature has them Or that they harden without cleavage of volatile constituents. To a limited extent, for the purpose of the invention, they can be continued with powdered or granular fillers such as quartz flour, mica flour, etc. Examples of usable organic fibers for the reinforcing material are polyethylene terephthalate fibers ("Terylene", "Dacron"), polyvinylidene chloride (sarphide) polyacrylonitrile fibers ("Orlon"), polyamide fibers ("Nylon", "PerIon") and similar fibers, which are usually produced by drawing from a melt or a solution. Such fibers have the property of shrinking upon heating to a temperature at which the molecules can move out of their stretched state obtained during manufacture. The reinforcement material can. advantageously have the shape of a warp, a warp band, or a yarn which is wound around the bushing bolt suitably with some tightening. The plastic can be supplied in different ways. One can e.g. apply the plastic by impregnating the reinforcement material with it, before applying the reinforcement material to the bolt. You can too. adhere the plastic at the same time as or in connection with the reinforcement material being wound around the bolt, e.g. by habit palindat vary of the fibrous material coated with plastic before Riljande vary paThres. Pet Or () ask possible to first apply the fibrous material and then add plastic through an impregnation process, with or without. use of vacuum. According to a very advantageous embodiment of the invention, the organic fibers consist of polyethylene terephthalate and the completely polymerizable plastic of an epoxy resin.

I vissa fall kan gastata forbindningar erhallas mellan bulten och en omgivande isolering genom omgjutning av bulten med en. med korta fibrer av armeringsmaterialet forsatt plast. In some cases, gas-tight connections can be obtained between the bolt and a surrounding insulation by recasting the bolt with a. with short fibers of the reinforcing material continued plastic.

Uppfinningen forklaras narmare med referens till den bifogade figuren genom 101- jande beskrivning av en som exempel vald utfaringsform. Den. genomforingsbult 1, som skall isoleras, omlindas med halv overlapp med ett 0,13 mm tjockt och 20 mm brett, va.vt band av terylenfibrer med vikten 120 g/m2. Sedan bulten forsett med ett lager av dylikt band bestrykes lagret med en losningsmedelsfri epoxiplast (t. ex. »Araldit F» forsatt med lika mangd »Ilardare 905» och 0,5 viktsprocent »Accelerator 905», raknat pa sammanlagda mangden av harts och hardare, vilka produkter tillverkas av Ciba AG, Schweiz). Darefter lindas ett nytt lager terylenband pa, varefter detta bestrykes med den narnnda plasten. Proceduren upprepas tills en isolering av onskad tjocklek erhallits. Den med isolering forsedda bulten uppvarmes sedan for hardning av plasten, i detta fall till 130° C under 1 tim. Dot har visat sig lampligt att efter en ordinar hardning av plasten underkasta den isolerade bulten en fortsatt varmebehandling i och for en efterhardning av plasten och att darvid utfora denna vid samma eller en nagot lagre temperatur an den vilken den ordinara hardningen utforts vid. I den speciellt beskrivna utforingsformen Or dot lampligt att utfora efterhardningen vid 120° C under 36 tim. Ellen hardningen bildar isoleringen ett holje 2 omkring bulten. Ytan av haljet kan vid behov ytbehandlas. I figuren Or den isolerade genomforingsbulten anbringad i en urborrning 3 i vaggen 4 av en vatgaskyld elektrisk maskin. Tatningen mellan den isolerade genomforingsbulten och ha-lets vaggar astadkommes med tatningsringar 5 av gummi. Tatningsringarna tryckas mot en underlaggsring 6 av muttern 7 via en distansring 8, som Or forsedd med en stoppskruv belagen i ett vertikalt spar 10 i urborrningen. The invention is explained in more detail with reference to the appended figure by 101st description of an exemplary embodiment. The. bushing bolt 1, which is to be insulated, is wrapped with half overlap with a 0.13 mm thick and 20 mm wide, vvv band of terylene fibers weighing 120 g / m2. After the bolt is provided with a layer of such tape, the layer is coated with a solvent-free epoxy plastic (eg »Araldit F» continued with equal amount »Ilardare 905» and 0.5% by weight «Accelerator 905», calculated on the total amount of resin and harder , which products are manufactured by Ciba AG, Switzerland). A new layer of terylene tape is then wound on, after which it is coated with the said plastic. The procedure is repeated until an insulation of the desired thickness is obtained. The insulated bolt is then heated to harden the plastic, in this case to 130 ° C for 1 hour. Dot has been found to be suitable to, after an ordinary hardening of the plastic, subject the insulated bolt to a continued heat treatment in order for a post-hardening of the plastic and to perform this at the same or a slightly lower temperature than the one at which the ordinary hardening was performed. In the specially described embodiment Or dot it is convenient to perform the post-curing at 120 ° C for 36 hours. Ellen hardening forms the insulation a casing 2 around the bolt. The surface of the tail can be surface treated if necessary. In figure Or the insulated bushing bolt is fitted in a bore 3 in the cradle 4 of a water-gas-cooled electric machine. The seal between the insulated bushing bolt and the rocker of the hole is provided with rubber seal rings 5. The sealing rings are pressed against a base ring 6 by the nut 7 via a spacer ring 8, which Or is provided with a stop screw coated in a vertical groove 10 in the bore.

Fastan uppfirmingen icke Or bunden vid nagon teori kan del dock antagas att den. utomordentligt tata forbindning som erhalles vid anvandning av sattet enligt uppfinningen har sin grund i en krympning scmi tradarna i armeringsmaterialet undergar vid hardningen av den fullstandigt polymeriserbara plasten. Enligt donna teori skulle det vid tradarnas sammandragning uppkomna krymptrycket bidra till bindningen och tatningen mot bulten. Although the invention is not bound by any theory, it can be assumed that it. The extremely tight connection obtained when using the set according to the invention is due to a shrinkage which the threads in the reinforcing material undergo during the hardening of the completely polymerizable plastic. According to Donna's theory, the shrinkage pressure created by the contraction of the trades would contribute to the bonding and tightening against the bolt.

Det Or uppenbart att en isolerad bult fram- — —3 stand enligt uppfinningen jute bara med for-del kan anvandas i enlighet med det angivna exemplet vid vdtgaskylda elektriska maskiner utan doyen vid andra gaskylda maskiner, liksom vid manga andra maskiner och apparater, vid vilka det är av vikt att forbindningen mellan en genomforingsbult och en denna omgivande isolation ãr tat mot gaser och vatskor. It is obvious that an insulated bolt - —3 stand according to the invention jute only with advantage can be used in accordance with the given example in hydrogen gas-cooled electrical machines without the doyen in other gas-cooled machines, as well as in many other machines and apparatus, in which it is important that the connection between a bushing bolt and a ambient insulation is tat against gases and water shoes.

Claims (4)

Patentansprik:Patent claim: 1. Slit att astadkomma en gastdt f5rbindning mellan en metallisk genomforingsbult och en genomforingsbulten omgivande isolering, viiken innefattar en fullstandigt polymeriserbar plast t. ex. en polyesterplast eller en epoxiplast, som hardats efter det plasten anbringats runt genomforingsbulten, kdnnetecknat ddrav, att den fullstandigt polymeri serbara plasten och ett av syntetiska, organiska fibrer uppbyggt armeringsmaterial for plasten anbringas omkring genomforingsbulten, varefter plasten overfores i hardat till-stand.Wear to provide a tight connection between a metallic bushing bolt and a bushing surrounding insulation, which comprises a fully polymerizable plastic e.g. a polyester plastic or an epoxy plastic which has hardened after the plastic has been applied around the bushing bolt, characterized in that the fully polymerizable plastic and a synthetic organic fiber reinforcing material for the plastic are applied around the bushing bolt, after which the plastic is transferred in the cured state. 2. Sat enligt patentanspraket 1, kannetecknat ddrav, att genomforingsbulten forses med ett tunt skikt av ett elastiskt material, t. ex. silikongummi, innan plasten och armeringsmaterialet anbringas.2. A kit according to claim 1, characterized in that the bushing bolt is provided with a thin layer of an elastic material, e.g. silicone rubber, before applying the plastic and reinforcement material. 3. Satt enligt patentanspraken 1 och 2, kannetecknat ddrav, att armeringsmaterialet appliceras i form av en vdv eller vavt band, som lindas omkring genomforingsbulten. 4. Satt enligt patentansprAken 1-3, kdnnetecknat ddray, att armeringsmaterialet dr tillverkat av polyetentereftalatfibrer. 5. Isolerad genomforingsbult framstalld enligt nagot av patentanspraken 1-3. A kit according to claims 1 and 2, characterized in that the reinforcing material is applied in the form of a woven or wavy band, which is wound around the bushing bolt. 4. According to patent claims 1-3, characterized in that the reinforcing material there is made of polyethylene terephthalate fibers. 5. Insulated bushing bolt according to any one of patent claims 1- 4. Anforda publikationer: Stockholm 1961. liungl. Boktr. P. A. Norstcdt & Saner. 6100894. Request publications: Stockholm 1961. liungl. Boktr. P. A. Norstcdt & Saner. 610089