SE129103C1

SE129103C1 -

Info

Publication number: SE129103C1
Authority: SE
Publication date: 1950-01-01

Description

KLASS 21 c:72 BESKRIVNING OFFENTLIGGJORD AV KUNGL. PATENT- OCH REGISTRERINGSVERKET BEVILJAT DEN 1 JUN! 1950 PATENTTID FRAN DEN 19 OKT. 1946 PUBLICERAT DEN 15 AUGUST! 19 Ans. den "/,, 1946, nr 9123/1946. Hartill en ritning. CLASS 21 c: 72 DESCRIPTION PUBLISHED BY KUNGL. PATENT AND REGISTRATION AGENCY GRANTED ON 1 JUNE! 1950 PATENT PERIOD FROM OCTOBER 19. 1946 PUBLISHED ON AUGUST 15! 19 Ans. the "/ ,, 1946, No. 9123/1946. Hitherto a drawing.

D. MaLER-HILLEBRAND, ABRAHAMSBERG. D. MaLER-HILLEBRAND, ABRAHAMSBERG.

Skyddsmantel far i overspanningsavledare befintliga ventilelement. Protective jacket father in overvoltage arrester existing valve elements.

Motstandsblock utgora en viktig bestandsdel av ventilayledare. De hava till uppgift dels att efter det avledaren barjat fungera leda en av overspanningen betingad strom, utan att spanningen Over blocket far uppga till ett for anlaggningens isolation skadligt varde, dels att dampa en efter detta forlopp foljande driftstram och med sakerhet bryta densamma. I overensstammelse harmed är ventilelementets motstand Met vid stora strommar och stort vid sma strOmmar. Vid det vanligaste utforandet av ventilelement for Overspanningsavledare ledes strommen genorn horn av kiselkarbid, varvid de enskilda kornen be-Tom a varandra eller aro inbaddade i en poros kropp pa litet avstand fran varandra. Enligt den gangse uppfattningen passerar strommen fran korn till korn Over kontaktstallena mel- Ian dem ,eller ocksa uppstar en liten ljusbage Indian kornen. Sadana ventilelement dimensioneras for en varaktighet av strommen av nagra tiotal till nagra hundra mikrosekunder. Om en strom av nagra hundra till nagra tusen A genomflyter anordningen, uppstar ett spaningsfall over ett ventilelement av nagra tusen volt per cm av ventilelementets 118,0. Resistance blocks are an important component of valve conductors. They have the task, partly after the arrester has started to function, to conduct a current due to the overvoltage, without the voltage across the block having to be harmful to the insulation of the system, and partly to steam an operating voltage following this process and safely break it. Accordingly, the resistance of the valve element is Met at large currents and large at small currents. In the most common embodiment of valve elements for surge arresters, the current is passed through horns of silicon carbide, the individual grains being empty of each other or embedded in a porous body at a small distance from each other. According to popular belief, the current passes from grain to grain. Such valve elements are dimensioned for a duration of the current of a few tens to a few hundred microseconds. If a current of a few hundred to a few thousand A flows through the device, a reconnaissance drop occurs over a valve element of a few thousand volts per cm of the valve element 118.0.

FOr att undvika overslag utefter mantelytan, vilka skulle kunna uppsta genom detta spannigsfall, dr det brukligt att forse mantelytan med en skyddsfarg eller att giva den ett hart och starkt overdrag. Man kan ocksa gjuta omkring den t. ex. med kabelmassa. Om man belastar Adana ventilelement med strommar frau nagra hundra till nagra tusen A under tider, som overstiga 100gs och kunna existera under mer On 1000gs, upptrader en stark mekanisk verkan av strommen pa .overdraget eller gjutmassan. Strommen medfor namligen temperaturstegringar upp till bver 20000 vid kontaktstallena mellan de enskilda kornen. Varmeutvecklingen Or proportionell mot tiden, oberoende av om strommen flyter Over kontakter eller ljusbagar. Genom (Telma varmeutveckling astadkommes en stark upphettning av luften. Denna utvidgar sig stotartat och Iran de stallen, dar trycket alstras, utga. starka tryckvagor, som atfoljas av zoner med starkt minskad tathet hos luften. Elf hart overdrag uthardar icke den stot artade pakanningen. Till och med mjuka gjutmassor bliva sproda vid denna pakanning och spricka latt solider. Harav blir foljden antingen att enskilda partiklar av overdraget lossna eller att sprickor uppsta i overdragel. I varje fall uppsta latt overslag i gransskiktet mellan ventilelementet och skyddsoverdraget eller langs det sistnamnda. Det Or sarskilt karakteristiskt for detta forlopp, all dessa overslag icke sammanfalla med strommens maximivarde utan ofta intraffa nagot senare, dO strOmmen nedgatt till endast nag-ma procent eller till och med promille av sitt ursprungliga varde. In order to avoid projections along the mantle surface, which could arise due to this voltage drop, it is customary to provide the mantle surface with a protective paint or to give it a hard and strong coating. You can also cast around it e.g. with cable mass. If you load Adana valve elements with currents from a few hundred to a few thousand A during times that exceed 100gs and can exist for more than 1000gs, a strong mechanical effect of the current on the coating or casting mass occurs. The current causes temperature rises up to over 20,000 at the contact points between the individual grains. Heat evolution Or proportional to time, regardless of whether the current is flowing Over contacts or candle holders. Through (Telma heat development) a strong heating of the air is achieved. This expands stubbornly and Iran the stables where the pressure is generated, emit strong pressure waves, which are accompanied by zones with greatly reduced density of the air. Even soft castings become cracked during this packing and crack slightly solid, resulting in either individual particles of the coating coming loose or cracks arising in the coating. Particularly characteristic of this course, all these estimates do not coincide with the maximum value of the current but often occur somewhat later, when the current has decreased to only a few per cent or even per mille of its original value.

For att undvika sadana overslag eller genomslag Or enligt uppfiningen manteln fOr de ytor, vid vilka ett potentialfall uppkommer ph grund av striimmens passage, utford p0 sadant satt, att den genom sin elasticitet kan upptaga mekaniska stotar och tryckvagor. Huvudbestandsdelen av mantel', som astadkommer elasticiteten, utgores foretradesvis av fiberamnen Dessa fiberbestandsdelar kunna utgoras av silke, hampa, glasull, glastradar, ashes t eller tramassa. Materialel kan pressas omkring ventilelementet, men det kan ocksa strykas, sprutas eller lindas pa detsamma eller dragas utanpa elementet liksom en strumpa. Sasom bindemedel kan man anvanda godtyckliga klisteramnen, t. ex. lack eller kitt. Harvid Or det lampligt att anvanda foreningar eller blandningar, som hava en -viss slaktskap med ventilelementets bestandsdelar, t. ex. vattenglas, portland-cement, klor-zinklosning, schellack, bakelit, small svavel eller klisterlack, alla i forening med sadana fyllnadsamnen, som anvandas vid kittning. Man kan emellertid Oven undvara sarskilda kittamnen, om man pafor skyddsmanteln med en viss forspanning exempelvis genom att man pafor kiselharts i flytande form, som krymper nagot vid forkningen. For detta andamal kunna Oven andra sjalvhardande eller vid hOgre temperatur hardnande plastiska material anvandas. In order to avoid such overshoots or breakthroughs. The main constituent of the mantle, which provides the elasticity, is preferably composed of the fiber blanks. These fibrous constituents may be composed of silk, hemp, glass wool, glass radar, ashes or pulp. Material can be pressed around the valve element, but it can also be ironed, sprayed or wound on the same or pulled on the outside of the element like a sock. Any adhesive can be used as an adhesive, e.g. varnish or putty. Is it appropriate to use compounds or mixtures which have a certain relationship with the components of the valve element, e.g. water glass, portland cement, chlorine-zinc solution, shellac, bakelite, small sulfur or adhesive varnish, all in conjunction with such fillers, which are used in putty. However, it is also possible to dispense with special putty names if the protective sheath is applied with a certain prestress, for example by applying silica resin in liquid form, which shrinks somewhat during exploration. For this purpose, other self-curing or at higher temperature hardening plastic materials can also be used.

Pa bifogade ritning visar fig. 1 en utforingsform av uppfinningen i perspektiv och fig. 2 densamma i sektion. Med 1 betecknas ventilelementet med kontaktytorna 2. och 3. In the accompanying drawing, Fig. 1 shows an embodiment of the invention in perspective and Fig. 2 the same in section. Denoted by 1 is the valve element with the contact surfaces 2. and 3.

— — Ventilelementet kan vara utfort i ett enda stycke, men det ken ocksa vara sammansatt av flera enskilda delar. Det har icke nagon betydelse for uppfiningen, om beroringsytorna mellan dessa enskilda delar aro metalliserade eller om de med eller utan metallisering arc anordnade i onriedelbar, ledande beroring med varandra eller skilda frau varandra av sma mellanrum. Ventilelementets form ken vara cylindrisk, konisk eller rektangular och Ar averhuvud taget godtycklig. Vid den visade utforingsformen bestar manteln av ell snare 4 ay hampa, asbest eller spunnet glas, som ar lindat omkring cyllndern. Med 5 betecknas bindemedlet, som forbinder den elastiska manteln med ventilelementet och sammanhaller den. - - The valve element can be made in a single piece, but it can also be composed of several individual parts. It does not matter to the invention whether the contact surfaces between these individual parts are metallized or whether they are arranged with or without metallization in indivisible, conductive contact with each other or separated from each other by small spaces. The shape of the valve element can be cylindrical, conical or rectangular and is generally arbitrary. In the embodiment shown, the jacket consists of or rather 4 hemp, asbestos or spun glass, which is wrapped around the cylinder. Denoted by 5 is the adhesive which connects the elastic jacket to the valve element and holds it together.

Claims

Patent claim:

Protective sheath for valve elements of resistance material present in surge arresters with surfaces, according to which a potential drop occurs in discharges, characterized in that it consists of a valve element enclosing winding of fibrous material, such as hemp, asbestos, glass cords or the like, which are connected to the valve element with deist varnish or putty.

Protective jacket according to claim 1, characterized in that it takes the form of a sock enclosing a valve element, which consists mainly of spun, elastic fibers.