SE201248C1

SE201248C1 -

Info

Publication number: SE201248C1
Authority: SE
Publication date: 1965-01-01

Description

Uppfinnare: J L L Hood Prioritet begtird frit' n den 2 juni 1959 (Storbritannien) Foreliggande uppfinning avser antistatisk behandling av flexibel filmslang. Inventor: J L L Hood Priority Begtird Free June 2, 1959 (United Kingdom) The present invention relates to antistatic treatment of flexible film tubing.

Flexibel filmslang av termoplastmaterial, sasom polyeten framstallas vanligtvis genom s. k. »blasstrangsprutning» vid vilken det filmbildande materialet i upphettat smalt till-stand strangsprutas genom en ringformig oppning for att pa sa satt bilda ett ror eller en slang, som omedelbart utvidgas genom en fasthallen gasbubbla inne i slangen for att Moja vaggen till Onskad tjocklek, atfoljt av nedkylning av slangen till under materialets stelningstemperatur samt tillplattning och avdragning av slangen mellan ett par roterande klamvalsar vilka aven tjanstgOra som gassparr for den fasthallna gasbubblan. Flexible film tubing of thermoplastic material, such as polyethylene, is usually made by so-called "blow extrusion" in which the film-forming material in the heated narrow state is extruded through an annular opening so as to form a tube or tube which is immediately expanded through a fixed gas bubble inside. in the hose to Moja the cradle to the desired thickness, followed by cooling of the hose to below the solidification temperature of the material and flattening and pulling of the hose between a pair of rotating clamp rollers which also serve as a gas barrier for the retained gas bubble.

Den tillplattade filmslangen, som stundom Or kand under benamningen »flatliggande slang» (lay-flat tubing), ledes darefter runt en eller flera styrrullar till en upplindningsvals dar den upplindas pa en karna for expediering till forbrukaren. The flattened film hose, sometimes referred to as "lay-flat tubing", is then passed around one or more guide rollers to a winding roller where it is wound on a core for dispatch to the consumer.

Det finnes manga kommersiella anvOndningsomraden fOr filmslang. Den ena kanten kan skaras upp och filmen oppnas och pa sâ satt bilda film i form av ark eller ocksa kan filmen latt omvandlas till pasar i en snabbgaende maskin for pasframstallning genom tvargaende forslutning av tva motstaende vaggat i filmslangen med forutbestamda intervall, atfoljd av avskarning tvars over filmen i narheten av vane fOrslutning for att skilja de enskilda pa.sarna Manga av de material som anvandas fOr framstallning av filmslang aro kansliga fOr att antaga elektrostatiska laddningar och sadana laddningar komma till uttryck pa filmslangens inner- och yttersidor under framstallningen. De laddningar som bildas pa insidorna aro sarskilt besvarliga eftersom de genom inb8rdes attraktion fororsaka att filmens inatvanda ytor klibba fast vid varandra med resultat att svarigheter uppsta att oppna en filmslang after uppklippning for att bilda ett enkelt ark eller att oppna en pase hildad av filmslangen i avsikt att fylla densamma. liven dà filmslangens bada vaggar ha skilts at, forefinnes en utpraglad tendens hos vaggarna att atergâ i kontakt med varandra. There are many commercial uses for film tubing. One edge can be cut open and the film opened and thus form a film in the form of sheets or the film can also be easily converted into a pass in a high-speed pass-making machine by transversely closing two opposite cradles in the film hose at predetermined intervals, followed by cutting across over the film near habit closure to separate the individual passages Many of the materials used to make film tubing are likely to assume electrostatic charges and such charges are expressed on the inner and outer sides of the film tubing during manufacture. The charges formed on the insides are particularly responsive because, by mutual attraction, they cause the wet surfaces of the film to stick together, with the result that similarities arise in opening a film hose after cutting to form a single sheet or in opening a passage hollowed out by the film hose. to fill the same. life when the two cradles of the film hose have separated, there is a pronounced tendency in the cradles to return in contact with each other.

Foremalet for foreliggande uppfinning Or i huvudsak att eliminera sa.dana elektrostatiska laddningar som bildas ph insidan av en. filmslang av sadant material som Or kansligt for antagande av elektrostatiska laddningar. I enlighet med foreliggande uppfinning omfattar ett forfarande for eliminering av elektrostatiska laddningar pa insidan av en flexibel filmslang av ett for elektrostatisk laddning mottagligt material uppblasning av filmslangen med ett gasformigt medium, tillrackligt for att i huvudsak utsatta hela insidan av filmslangen for det gasformiga mediet och jonisering av det gasformiga mediet i sadan grad, att de pa insidan av filmslangen befintliga elektrostatiska laddningarna elektriskt neutraliseras. The object of the present invention is essentially to eliminate such electrostatic charges which are formed inside one. film tubing of such material as Or probable for the assumption of electrostatic charges. In accordance with the present invention, a method of eliminating electrostatic charges on the inside of a flexible film hose of a material susceptible to electrostatic charge comprises inflating the film hose with a gaseous medium, sufficient to expose substantially the entire inside of the film hose to the gaseous medium and ionizing of the gaseous medium to such an extent that the electrostatic charges present on the inside of the film hose are electrically neutralized.

I en foredragen form av uppfinningen joniseras det gasformiga mediet som inneslutes i den uppblasta filmslangen genom att utsattas for en elektrostatisk spa.nningskalla mel- 2 Ian ett par elektroder placerade intill, men foretradesvis pa hada sidor om filmslangen och som betjanas med en elektrisk vaxelspanning med en storlek i stand att jonisera det gasformiga mediet men jute tillracklig for att ge upphov till en gnisturladdning mellan elektroderna. In a preferred form of the invention, the gaseous medium enclosed in the inflated film hose is ionized by being subjected to an electrostatic voltage source between a pair of electrodes placed adjacent to, but preferably on, two sides of the film hose and operated with an electrical alternating voltage with a size capable of ionizing the gaseous medium but jute sufficient to give rise to a spark discharge between the electrodes.

Filmslangen behandlas lampligen enligt ett kontinuerligt forfarande genom att den Mr passera -mellan ett par stationara elektroder, varvid filmen uppblases i narheten av elektroderna med en fasthallen bubbla av ett gasformigt medium, t. ex. luft, som Hiles innesluten i den lopande filmslangen mellan atskilda valsar. Krakningen av filmslangen runt en stor haze av valsamas omkrets kan vara tillrackligt for att halla kvar den inneslutna bubblan i filmslangen mellan rullarna. Emellertid aro de tva atskilda rullarna foretradesvis forbundna med ytterligare rullar, bestaende av klamrullar, for att forhindra att det gasformiga mediet forsvinner fran bubblan. The film tubing is suitably treated according to a continuous process by passing it between a pair of stationary electrodes, the film being inflated near the electrodes with a fixed bubble of a gaseous medium, e.g. air, which Hiles encloses in the running film hose between separate rollers. The cracking of the film hose around a large haze of the circumference of the rollers may be sufficient to retain the entrapped bubble in the film hose between the rollers. However, the two separate rollers are preferably connected by additional rollers, consisting of clamping rollers, to prevent the gaseous medium from disappearing from the bubble.

Elektroderna kunna vara av vilket som heist vanligt slag, men aro foretradesvis stayformiga och placerade tvars emot varandra pa hada sidor om filmslangen. Elektrodema behova jute vara isolerade, men for att undvika mojligheten av en gnisturladdning mellan dem är det, isynnerhet vid de andar som jute avskarmas ay filmslangen, att foredraga att belagga eller pa annat satt tacka dem med ett elektriskt isolerande material. En pa lamp-lit salt isolerad elektrod att anvandas vid sat- letforeliggande uppfinning utgores av en bit glasror pa insidan belagd med ett lager av elektriskt ledande kolloidalgrafit. Optima-la resultat erhallas da filmslangen befinner sig i kontakt med elektroderna varvid foretradesvis filmslangen ar uppblast i sadan grad, att, vid franvaro av elektroder, den skulle komma att antaga en diameter storre an avstandet mellan elektroderna, sà att elektroderna fororsaka en hopsnoming av den uppblasta filmslangen och i konsekvens harav delvis arc insvepta av filmen. Den elektriska vaxelspanningen som palagges elektroderna halles vid ett minimum eftersom okad potential medfor 8kad tendens hos filmslangen att klibba vid elektroderna och harigenom resulterar i dragning da filmen behandlas enligt ett kontinuerligt forfarande. The electrodes may be of the usual type, but are preferably stay-shaped and placed opposite each other on either side of the film tube. The electrodes need to be jute insulated, but in order to avoid the possibility of a spark discharge between them, it is, especially with the spirits that jute is shielded in the film hose, to prefer to coat or otherwise thank them with an electrically insulating material. A lamp-salt-insulated electrode to be used in the satellite present invention consists of a piece of glass tube on the inside coated with a layer of electrically conductive colloidal graphite. Optimal results are obtained when the film tube is in contact with the electrodes, preferably the film tube is inflated to such an extent that, in the absence of electrodes, it would assume a diameter greater than the distance between the electrodes, so that the electrodes cause an accumulation of the electrode. inflate the film tube and consequently partially arc wrapped around the film. The electrical AC voltage applied to the electrodes is kept to a minimum because the increased potential causes the film hose to stick to the electrodes and thereby results in traction when the film is treated according to a continuous process.

Dessutom, eftersom den minsta elektriska spanning som erfordras for att effektivt neu-tralisera de elektrostatiska laddningarna pa filmslangens insida akar med Rat avstand mellan elektroderna, är det att foredraga att elektroderna placeras sa nara varandra som det är praktiskt mojligt. Ett lampligt avstand mellan elektroderna är 1,59-6,35 mm. In addition, since the minimum electrical voltage required to effectively neutralize the electrostatic charges on the inside of the film tube is at a spaced distance between the electrodes, it is preferable that the electrodes be placed as close to each other as is practically possible. A suitable distance between the electrodes is 1.59-6.35 mm.

,Den minsta effektiva elektriska spanning som erfordras f8r ett visst bestamt avstand mellan elektroderna, typ av elektroder och isoleringens tjockIek, om sadan finnes, kan la.tt bestammas genom att lata en filmslang med elektrostatiska laddningar pa insidan och i uppblast tillstan.d passera mellan ett par av elektroderna vilka palaggas en elektrisk vaxelspanning, varvid potentialen efterhand Ras stegvis och de aterstaende elektrostatiska -laddningarna-pa insidorna av den behandlade filmen bestammas efter varje steg. Den minsta effektiva elektriska spanningen är den lagsta spanning vid vilken den behandlade filmslangen jute har nagon kvarstaende elektrisk laddning pa insidan. The minimum effective electrical voltage required for a certain distance between the electrodes, the type of electrodes and the thickness of the insulation, if any, can be determined by passing a film hose with electrostatic charges on the inside and in an inflated state. a pair of the electrodes which are applied to an electrical alternating voltage, the potential being gradually increased in stages and the remaining electrostatic charges on the insides of the treated film being determined after each step. The least effective electrical voltage is the lowest voltage at which the treated film hose jute has any residual electrical charge on the inside.

Om en viss del av en filmslang har nagra elektrostatiska laddningar pa insidorna eller ej kan grovt bestammas genom att taga en del av filmen i tillplattad form, avlagsna eventuella elektrostatiska laddningar pa utsidorna genom borstning med handen eller med en fuktig tygbit eller med flagon annan kand metod och darefter oppna slangen. Minsta tendens hos filmslangen att Ater vilja sluta sig anger narvaron av elektrostatiska laddningar pa insidorna. If a certain part of a film hose has some electrostatic charges on the inside or can not be roughly determined by taking part of the film in a flattened form, remove any electrostatic charges on the outside by brushing with your hand or with a damp piece of cloth or with flake other known method and then open the hose. The slightest tendency of the film hose to want to close again indicates the presence of electrostatic charges on the insides.

En sakrare metod for bestamning av narvaron av elektrostatiska laddningar invandigt i filmslangen är att skara ut en rund skiva ur den tillplattade filmen och att maim den laddning som registreras av en elektrostatisk voltmeter da ett lager ay filmen avlagsnas fran det andra lagret av den dubbla skivan. A more accurate method of determining the presence of electrostatic charges inside the film tube is to cut a round disc out of the flattened film and to measure the charge detected by an electrostatic voltmeter when a layer of the film is removed from the second layer of the double disc.

I praktiken har det visat sig, att far elektroder bestaende av tunnvaggiga »Pyrex» (inregistrerat varumarke) glasror, 12,7 mm i diameter, pa insidan belagda med kolloidalgrafit for att bilda ett elektriskt ledan.de skikt och placerade med ett inb6rdes avstand ay 2,54 mm, am en lamplig elektrisk vaxelspanning for att astadkomma neutralisering ay de elektrostatiska laddningarna pO. insidoma av filmslangen av polyeten av storleksordningen 11-12 kilovolt (effektivvarde). For liknande elektroder belagna p0. ett avstand av 1 turn fran varandra är den elektriska vaxelspanning som erfordras f6r att samma resultat skall uppnas ay storleksordningen 20-22 kV. For elektroder bestaende ay massingsstavar, 12,7 mm i diameter, overdragna med en polyester-film med en tjocklek av 0,127 mm och placerade pa ett avstand av 2,54 mm fran varandra, am den lampliga elektriska vaxelspanningen ay storleksordningen 9-10 kV. In practice it has been found that electrodes consisting of thin-walled "Pyrex" (registered trademark) glass tubes, 12.7 mm in diameter, are coated on the inside with colloidal graphite to form an electrically conductive layer and placed at a mutual distance ay 2.54 mm, am a suitable electrical alternating voltage to achieve neutralization of the electrostatic charges pO. the insides of the polyethylene film hose of the order of 11-12 kilovolts (effective value). For similar electrodes coated p0. a distance of 1 turn from each other is the electrical alternating voltage required for the same result to be achieved in the order of 20-22 kV. For electrodes consisting of massing rods, 12,7 mm in diameter, coated with a polyester film with a thickness of 0,127 mm and placed at a distance of 2,54 mm from each other, the suitable electrical alternating voltage of the order of 9-10 kV.

Sattet att neutralisera elektrostatiska laddningar som bildats pa insidorna av filmslangen i enlighet med foreliggande uppfinning kan lampligen inforas som ett steg vid kontinuerlig framstallning av sadan film medan filmen kontinuerligt ledes frail rullar som samman- 3 pressa filmslangen, vilka rullar tillhora en strangsprutningsanordning for filmslang, till en upplindningsvals. De basta resultaten app-rids om sattet genomfores omedelbart fore det att filmen upplindas i form av en rulle for leverans till forbrukaren, eftersom det är troligt att en filmslang antager elektrostatiska laddningar p insidorna under handhavandet i det uppblasta eller flatliggande stadiet da en insida gnides i kontakt med den andra ytan. Om sâ erfordras kan emellertid neutraliseringen av de elektrostatiska laddningarna pa insidan genomfOras som en separat operation genom att filmslangen lindas fran en mile till en annan. The method of neutralizing electrostatic charges formed on the insides of the film hose in accordance with the present invention can be conveniently introduced as a step in continuously producing such a film while the film is continuously passed from rollers compressing the film hose, which rollers belong to a film hose extruder, to a winding roller. The best results are app-ridden if the set is carried out immediately before the film is wound up in the form of a roll for delivery to the consumer, since it is likely that a film hose assumes electrostatic charges on the insides during handling in the inflated or flat stage when an inside is rubbed in contact with the other surface. However, if required, the neutralization of the electrostatic charges on the inside can be performed as a separate operation by winding the film hose from one mile to another.

Dar en fangslad bubbla av ett gasformigt medium, lampligen luft, anvandes for att blasa upp filmslangen, kan luften i horjan inforas i filmslangen med tillhjalp av en ihalig nal eller genom en fri ande av filmen da klamvalsarna tillfalligtvis frigoras. I det fall att sattet enligt fereliggande uppfinning utgor ett kompletterande steg vid en kontinuerlig framstallning av filmslang enligt ett blassfrangsprutningsforfarande, kan den fdngslade luftbubblan ernas genom att tillfalligt latta pa klamvalsarna vid strangsprutningsstallet och lata en del av luften forsvinna fran den fangs-lade bubblan som anyandes for att toja ut det smalta roret till det stalle ddr neutraliseringen av de elektrostatiska laddningarna pa insidan genomfOres. Where a trapped bubble of a gaseous medium, suitably air, is used to inflate the film hose, the air in the sheath can be introduced into the film hose by means of a hollow needle or through a free spirit of the film as the clamp rollers are occasionally released. In the case that the method of the present invention constitutes a complementary step in a continuous production of film hose according to a blow-spraying process, the trapped air bubbles can be accidentally let on the clamp rollers at the extrusion stall and let some of the air disappear from the trapped bubble. to stretch the narrow tube to the place where the neutralization of the electrostatic charges on the inside is carried out.

Da nyligen strangsprntad uppblast film-slang tillplattas mellan klamvalsarna bildas veck vid kanterna av den sammanpressade filmen. Pit liknande satt, vid framstallning av filmslang med dubbelvikta kanter, som vanligtvis formas med ett par kilformade organ placerade pa omse sidor om en. nyligen strangsprutad uppblast filmslang omedelbart fore sammanpressningsvalsarna fOr att trycka tva rnotstaende delar av filmen ink mot varandra och pit sit salt bilda dubbelveck eller kilar i den sammanpressade filmen, Midas veck vid kilarnas kanter. Da en sadan veckad film uppblases for det andamal som avses med foreliggande uppfinning och darefter tommes pa luft foreligger den m011igheten att filmslangen inte kommer att sjunka ihop pa de tidigare bildade vecken. En sadan eventualitet kan forebyggas genom att i narheten av elektroderna anbringa ett eller flera par av klamvalsar, vilka gripa tag i de veckade kanterna pa filmslangen med jamna mellanrum under uppblasningen av filmslangen. As newly extruded inflatable film tubing flattens between the clamp rollers, creases form at the edges of the compressed film. Pit similarly, in the manufacture of film tubing with double-folded edges, which are usually formed with a pair of wedge-shaped members placed on opposite sides of one another. recently extruded inflatable film hose immediately before the compression rollers to press two adjacent parts of the film into each other and pit its salt to form double folds or wedges in the compressed film, Midas folds at the edges of the wedges. Since such a pleated film is inflated for the purpose of the present invention and then emptied of air, there is a possibility that the film hose will not collapse on the previously formed folds. Such an eventuality can be prevented by arranging in the vicinity of the electrodes one or more pairs of clamping rollers, which grip the folded edges of the film hose at regular intervals during the inflation of the film hose.

Vid kontinuerlig framstallning av filmslang, sasom polyetenfilmslang, medfoljer allt emellanai frammande amnen sasom klumpar av det filmbildande materialet, fran matrisens framsida och folja med filmen. Da sadana klumpar aro storre an mellanrummet mellan elektroderna foreligger risk air att elektroderna eller filmen skadas. Sadan skada kan undvikas genom att anbringa ett kontrollorgan vilket vid registrering av att sadana frammande omnen medfolja fororsaka att elektroderna hoppa isar. FOretra.desvis utgores kontrollorganet av ett par fran varandra skilda stativ vart och ett uppbarande en elektrod och avgransande ett gap genom vilket filmslangen passerar innan den passerar mellan elektroderna, varvid minst ett av stativen kan svangas bort fran det andra organet som itr fiirsett med den till detta anslutna elektroden da frammande material som medfi5ljer filmslangen och som itr storre an oppningens storlek pressar mot stativet. In the continuous production of film tubing, such as polyethylene film tubing, everything between the emergent blanks, such as lumps of the film-forming material, comes from the front of the matrix and accompanies the film. As such lumps are larger than the space between the electrodes, there is a risk that the electrodes or film will be damaged. Such damage can be avoided by fitting a control means which, upon registration of such foreign matter, causes the electrodes to freeze. Preferably, the control means is constituted by a pair of spaced apart racks each carrying an electrode and defining a gap through which the film hose passes before passing between the electrodes, wherein at least one of the racks may be pivoted away from the other member provided with it to this connected electrode then advances material which accompanies the film hose and which, when larger than the size of the opening, presses against the frame.

Om sit onskas, kan eventuella pit filmslangens utsida upptradande elektrostatiska laddningar neutraliseras med tiihjiilp av flagon kand anordning for borttagande av statisk elektricitet antingen fore eller efter behandlingen av filmen i enlighet med uppfinningen. If desired, any extrinsic electrostatic charges occurring outside the pit of the film hose can be neutralized by means of a flake kand device for removing static electricity either before or after the treatment of the film in accordance with the invention.

Fyra illustrerande exempel av olika former att genomfora sattet enligt foreliggande uppfinning komma nu att beskrivas med hanvisRing till de medfoljande schematiska ritningarna dar fig. 1 ar en sidoprojektion av ett slag av behandlingsanordning, fig. 2 ar en plan av fig. 1, fig. 3 är en sidoprojektion av en anordning for kontinuerlig framstallning av filmslang inklusive behandlingsanordningen och fig. 4 är en vy uppifran av en modifikation av en del av anordningen enligt fig. 3. Fig. 5 visar ett snitt av fig. 4 efter linjen 5-5. Fig. 6 är en sidovy av en annan anordning for kontinuerlig framstallning av film- slang inklnsive behandlingsanordningen, fig. 7 visar framifran sett en del av fig. 6 och fig. 8 är en sektion tagen genom linjen 8-8 i fig. 7. Four illustrative examples of various forms of carrying out the method of the present invention will now be described with reference to the accompanying schematic drawings, in which: Fig. 1 is a side elevation of a type of treatment device; Fig. 2 is a plan view of Fig. 1; is a side view of a device for continuous production of film hose including the treatment device and Fig. 4 is a top view of a modification of a part of the device according to Fig. 3. Fig. 5 shows a section of Fig. 4 along the line 5-5. Fig. 6 is a side view of another device for continuous production of film hose including the treatment device, Fig. 7 shows a front view of a part of Fig. 6 and Fig. 8 is a section taken along line 8-8 in Fig. 7.

Exempel 1. Med hanvisning till fig. 1 och 2 leddes en flatliggande filmslang 1 av polyeten med elektrostatiska laddningar pa insidorna av filmen 1, vilka kommo till uttryck genom en utpraglad tendens hos filmen 1 att ater sluta sig tillsammans da den oppnades med handen och slapptes, fran en matarvals 2 genom tva par atskilda klamvalsar 3, 4 till en driven uppsamlingsvals 5. Example 1. Referring to Figs. 1 and 2, a flat film hose 1 of polyethylene with electrostatic charges was conducted on the insides of the film 1, which were expressed by a pronounced tendency of the film 1 to close together again when opened by hand and released. , from a feed roller 2 through two pairs of separate clamping rollers 3, 4 to a driven collecting roller 5.

Filmen 1 var 228,6 mm bred (i flatliggande tillstand) och hade en vaggtjocklek av 0,033 mm. Mellan de hada atskilda klamvalsparen 3 och 4 voro ett par elektroder 6 placerade mitt emot varandra pit omse sidor om filmen 1 och med ett inhOrdes avstand av 2,54 mm mellan vilka filmen 1 lick passera. The film 1 was 228.6 mm wide (in a flat state) and had a cradle thickness of 0.033 mm. Between the had separate clamp roller pairs 3 and 4, a pair of electrodes 6 were placed opposite each other on opposite sides of the film 1 and with a spaced distance of 2.54 mm between which the film 1 would pass.

Elektroderna 6 utgjordes av tunnvaggigt 2Tyrex» (inregistrerat varumarke) glasror, 12,7 mm i diameter och pa insidorna belagda 4 med kolloidalgrafit for att bilda ett elektriskt ledande skikt, varvid glasholj et bildar ett elektriskt isolerande skikt for det ledande skiktet. Den del av filmen 1 som befann sig emelIan de atskilda klamvalsarna 3 och 4 uppblastes med luft tillrackligt for att skilja insidorna pa filmen 1 fran varandra och M till stand att vaggarna pa filmen 1 delvis insvepte elektroderna 6 genom att blasa luft genom den fria anden av filmslangen 1 genom att tillfälligtvis latta pa trycket mellan klamvalsarna 4. The electrodes 6 consisted of thin-walled 2Tyrex (registered trademark) glass tubes, 12.7 mm in diameter and coated on the inside 4 with colloidal graphite to form an electrically conductive layer, the glass oil forming an electrically insulating layer for the conductive layer. The part of the film 1 located between the separate clamp rollers 3 and 4 was inflated with air sufficiently to separate the insides of the film 1 from each other and M able the cradles of the film 1 partially wrapped the electrodes 6 by blowing air through the free spirit of the film hose 1 by temporarily releasing the pressure between the staple rollers 4.

Matning av den elektrostatiska laddningen som fanns pa insidorna av fihnslangen 1 da denna passerade mellan valsarna 4 foretogs darefter pa foljande satt: En skiva, 127 ram i diameter, skars ut fran filmen i sektionen mellan valsarna 4 och valsen 5. Denna skiva, bestaende av tva lager i intim kontakt, lades pa en horisontell aluminiumplat ansluten till kontakten pa en elektrostatisk voltmeter pa vilken avlasningar fran 0 till 5 kV kunde Wins pa en icke linjar skala. Platen isolerades fran jord. Den andra anslutningskontakten pa den elektrostatiska voltmeter. anslots till jord. For att underlatta avlasningarna omkalibrerades voltmeterns skala sà att den kunde avlasas fran 0 till 30 enheter pa en linjar skala. Feeding of the electrostatic charge present on the insides of the fine tube 1 as it passed between the rollers 4 was then done as follows: A disc, 127 frames in diameter, was cut from the film in the section between the rollers 4 and the roller 5. This disc, consisting of two layers in intimate contact, were placed on a horizontal aluminum plate connected to the contact on an electrostatic voltmeter on which readings from 0 to 5 kV could Wins on a non-linear scale. The plate was isolated from earth. The second connection plug on the electrostatic voltmeter. connected to ground. To facilitate the readings, the scale of the voltmeter was recalibrated so that it could be read from 0 to 30 units on a linear scale.

Det owe lagret av den pa platen liggande dubbla skivan drags darefter hart fran det undre lagret, som fortfarande var i kontakt med platen, med tillhjalp av en isolerad tang varvid .voltmeterns visare svangde over skaIan och gay en avlasning som utgjorde ett matt pa den elektrostatiska laddningen melIan. de tva filmlagren som bildade den dubbla skivan. Proceduren upprepades tva ganger med nya skivor skurna ur filmen 1 och ett medelavlasningsvarde av 9,7 enheter erholls. The owe layer of the double disc lying on the plate is then pulled hard from the lower layer, which was still in contact with the plate, with the aid of an insulated pliers whereby the voltmeter's indicator swung over the scale and gay a reading that formed a mat on the electrostatic the charge melIan. the two film layers that formed the double disc. The procedure was repeated twice with new slices cut from the film 1 and an average reading value of 9.7 units was obtained.

En vaxelspanning (50 p/s) med vardet 7,6 kV palades darefter elektroderna 6 via en tillfOrselledning 7 frail en kalla 8 och fihnen 1 avdrogs fran valsen 2 medelst valsen 5 med en hastighet av 6,1 meter/min. Luftbubblan som hill's instangd mellan valsarna 3, 4 tjanade till att successivt blasa upp den frammafade filmen 1. An alternating voltage (50 p / s) with a value of 7.6 kV is then applied to the electrodes 6 via a supply line 7 from a cold 8 and the film 1 is withdrawn from the roller 2 by means of the roller 5 at a speed of 6.1 meters / min. The air bubble that Hill's trapped between the rollers 3, 4 served to gradually inflate the advanced film 1.

Provskivor utskuros ur filmen 1 sasom tidigare beskrivits och de kvarvarande elektrostatiska laddningarna uppmattes i exakt Overensstammelse med den ovan beskrivna metoden. Sample plates were excised from the film 1 as previously described and the remaining electrostatic charges were measured in Exact Compliance with the method described above.

Hela proceduren upprepades med hogre spanningar pMagda elektroderna 6 tills matningarna visade, att provskivoma inte hade na.gra kvarvarande elektrostatiska laddningar. De erhallna resultaten framga av tabell 1 nedan. The whole procedure was repeated with higher voltages on the electrodes 6 until the feeds showed that the sample discs did not have any remaining electrostatic charges. The results obtained are shown in Table 1 below.

ElektrodernaMatvarden utvisandeMedeltal p6lagd vaxelkvarvarande elektro- spanning i kVstatiska laddningar mellan filmlagren i provskivorna 0 7,13, 9 9,7 7,6 1, 2,2, 1,6 1,6 8,6 0,25, 0,8 0, 9,6 0,1 0,0,3 11,3 0,0 0,3 0, 12,8 0,0 0,0 0 Resultaten visade, att da en. vaxelspanning av c:a 12 kV palades elektroderna 6, joniserades luften mutt gasbubblan tillrackligt for att neutralisera de elektrostatiska laddningarna pa insidorna av filmen 1. The electrodes The food value showing the average applied alternating voltage between kVstatic charges between the film layers in the sample disks 0 7.13, 9 9.7 7.6 1, 2.2, 1.6 1.6 8.6 0.25, 0.8 0, 9.6 0.1 0.0.3 11.3 0.0 0.3 0, 12.8 0.0 0.0 0 The results showed that da en. alternating voltage of about 12 kV, the electrodes 6 were palladed, the air was ionized to the gas bubble sufficiently to neutralize the electrostatic charges on the inside of the film 1.

Filmslangen 1 pa valsen 2 behandlades darefter vid ett kontinuerligt forfarande sasom beskrivits med anvandande av vaxelspanning av 12 kV palagd elektroderna 6. The film hose 1 on the roller 2 was then treated in a continuous process as described using the AC voltage of the 12 kV padded electrodes 6.

Da den behandlade filmen 1 befrias frau eventuella elektrostatiska laddningar pa utsidorna genom att strykas med handen eller genom att behandlas enligt nagon kand metod for a-vlagsnande av statisk elektricitet, visade den sig vara mu att oppna och visade inte nagon tendens att vilja atertaga det slutna tillstandet. Pasar framstallda av filmen 1 i en standardmaskin for pasframstallning gingo latt att oppna och forblevo oppna varigenom ifyllningen av gods underlattades. When the treated film 1 is freed from any electrostatic charges on the outside by being ironed by hand or by treating according to any known method of a-removal of static electricity, it proved to be open and showed no tendency to want to take back the closed one. the condition. Bypasses made of the film 1 in a standard passport making machine were easy to open and remained open, thus facilitating the filling of goods.

Exempel 2. Refererande till fig. 3 framstalldes en filmslang 10 av polyeten genom stringsprutning av smalt polyeten genom en ringformig oppning 11 med en diameter av 101,6 mm i en form 12 och uppblasning av en slang utbildad genom en innesluten luftbubbla 14 mutt slangen 13. Den. uttojda slangen 13 kyldes med en ring av luftstrominar riktade frAn en ringformig lufttillforselkalla 15 placerad i narheten av formen 12 for att kyla ned polyetenen till under dess stelningstemperatur och pa sa satt hejda ytterligare uttojning genom uppblasning. Den nedkylda filmen 10 avdrogs darefter kontinuerligt Iran formen 12 och sammanpressades mellan ett par roterande klamvalsar 16. Luftbubbloma vilka fran borjan infordes genom roret 17, Milos inneslutna i slangen 10 mellan valsarna 16 och formen 12 och tjanade till att successivt blasa upp slangen 13. Uppblasnings- och kylningsbetingelserna voro si valda, att filmslangen 10 hade en vaggtjocklek av 0,03 mm och en bredd i tillplattat tillstand av 228,6 mm. Example 2. Referring to Fig. 3, a polyethylene film hose 10 was made by extruding narrow polyethylene through an annular opening 11 having a diameter of 101.6 mm in a mold 12 and inflating a hose formed by an enclosed air bubble 14 to the hose 13 The. the stretched hose 13 was cooled with a ring of air stromers directed from an annular air supply cooler 15 located near the mold 12 to cool the polyethylene to below its solidification temperature and thereby stop further stretching by inflation. The cooled film 10 was then continuously drawn from the mold 12 and compressed between a pair of rotating clamp rollers 16. The air bubbles which were initially introduced through the tube 17, Milos enclosed in the hose 10 between the rollers 16 and the mold 12 and served to successively inflate the hose 13. Inflation and the cooling conditions were chosen so that the film hose 10 had a cradle thickness of 0.03 mm and a width in the flattened state of 228.6 mm.

Den sammanpressade filmen 10 leddes mellan ett par statiska eliminatorer 18, 19 av konventionellt slag for att neutralisera eventuellt narvarande elektrostatiska laddningar pi utsidan av filmen 10 och leddes darefter mellan tva pa lampligt avstand fran varandra belagna par klam.valsar 20, 21 innan den slutligen lindades upp pa en driven vals 122 med en hastighet av 18,3 meter/min. MeIlan valsarna 20, 21 uppblastes filmen 10 anyo tillrackligt for att i huvudsak skilja insidorna at och leddes Indian och i kontakt med ett par elektroder 22 belagna pa ett avstand av 2,54 mm ifran varandra. The compressed film 10 is passed between a pair of static eliminators 18, 19 of conventional type to neutralize any electrostatic charges present on the outside of the film 10 and then passed between two suitably spaced pairs of clamping rollers 20, 21 before it is finally wound. up on a driven roller 122 at a speed of 18.3 meters / min. Between the rollers 20, 21, the film 10 was inflated sufficiently to substantially separate the insides of and guide the Indian and in contact with a pair of electrodes 22 coated at a distance of 2.54 mm from each other.

Elektroderna 22 bestodo av massingsror, 12,7 mm i diameter, omlindade med en polyesterfilm med en tjocklek av 0,127 mm och voro anslutna till en vaxelspanningskalla (50 p/s) pa 9 kV. Elektroderna 22 fororsakade en hopsnorning av filmen 10 pa sá satt, att filmen 10 delvis omslot elektroderna 22. The electrodes 22 consisted of massaging tubes, 12.7 mm in diameter, wrapped with a polyester film with a thickness of 0.127 mm and were connected to an AC voltage source (50 p / s) of 9 kV. The electrodes 22 caused the film 10 to constrict in such a way that the film 10 partially enclosed the electrodes 22.

Vid igangsattningen uppblastes filmen 10 mellan klamvalsarna 20, 21 i Onskad grad genom att tillfälligt Mita pa tryeket av klamvalsarna 16 och 20 tillrackligt fOr att tillata en del av luften att bortgâ frail luftbubblan 14 till den del av filmen 10 som passerade mellan valsarna 20, 21. Upon commissioning, the film 10 between the clamp rollers 20, 21 is inflated to the desired extent by temporarily measuring the pressure of the clamp rollers 16 and 20 sufficiently to allow a portion of the air to pass from the air bubble 14 to the portion of the film 10 which passed between the rollers 20, 21. .

Filmslangen 10 upplindad pa valsen 22 visade sig vara fullstandigt fri frOn elektrostatiska laddningar och kunde latt Oppnas utan nagon tendens hos filmen 10 att vilja Atertaga det tillplattade stadiet. The film tube 10 wound on the roll 22 was found to be completely free of electrostatic charges and could be easily opened without any tendency of the film 10 to want to return to the flattened stage.

For kontrollens skull upprepades den kontinuerliga framstallningen av filmslangen 10 utan att nagon spanning palades elektroderna 22. Den pa sa. salt erhallna filmen 10 var svar att oppna och da den slapptes atertog den det sammanpressade stadiet. For the sake of control, the continuous production of the film hose 10 was repeated without any voltage being applied to the electrodes 22. It so on. salt obtained film 10 was the answer to open and when it was released it resumed the compressed stage.

Exempel 3. Det i exempel 2 beskrivna forfarandet under hanvisning till fig. 3 upprepades med det tillagget, att tva veck eller kilformiga markea insattes pa diametralt motsatta stallen i filmslangen 10 omedelbart fore hoppressningen vid valsarna 16 med tillhjalp av ett par konventionella kilformiga organ (inte visade). Example 3. The procedure described in Example 2 with reference to Fig. 3 was repeated with the addition that two folds or wedge-shaped marks were inserted on the diametrically opposite stalls in the film hose 10 immediately before compression at the rollers 16 by means of a pair of conventional wedge-shaped members (not shown).

Under den vid kanterna dubbelvikta filmslangens 23 passage mellan klamvalsarna 20, 21 (fig. 4 och 5) hollos ytterkanterna pa filmen 23 mellan par av gripvalsar 24 for att sakerstalla att filmen vid sammanpressningen mellan klamvalsarna 21 simile pressas samman exakt i vecken. During the passage of the double-folded film hose 23 between the clamp rollers 20, 21 (Figs. 4 and 5), the outer edges of the film 23 are hollowed between pairs of gripping rollers 24 to ensure that the film is compressed exactly in the folds during the compression between the clamp rollers 21.

Gripvalsarna 24 voro nagot utatbojda for att eliminera nagon tendens hos den uppblasta filmen att skrynklas vid passagen mellan valsarna 24. The gripping rollers 24 were slightly bent out to eliminate any tendency of the inflated film to wrinkle at the passage between the rollers 24.

Exempel 4. Det i exempel 2 beskrivna fOrfarandet med referens till fig. 3 upprepades med den anordning som visas i fig. 6, 7 och 8. Example 4. The procedure described in Example 2 with reference to Fig. 3 was repeated with the device shown in Figs. 6, 7 and 8.

Den avkylda, uppblasta filmslangen 10 sammanpressades mellan ett par roterande klamvalsar 25, 26 bestaende av en driven stalvals 26 och en icke driven stodvals 25, forsatt i kontakt med valsen 26. The cooled, inflated film hose 10 was compressed between a pair of rotating clamping rollers 25, 26 consisting of a driven steel roller 26 and a non-driven standing roller 25, continued in contact with the roller 26.

Den sammanpressade filmslangen 10 led-des darefter runt en icke driven styrrulle 27 av stal, Over en driven stalstyrrulle 28 och upplindades pa en uppsamlingsvals 29. The compressed film hose 10 was then guided around a non-driven steel guide roller 27, over a driven steel guide roller 28 and wound on a collection roller 29.

En innesluten luftbubbla infordes I bOrjan i den del av filmslangen 10 som passerade mellan valsarna 27, 28 och tjanade till att successivt blasa upp filmslangen 10. En gummistodrulle 30 som pressades mot valsen 28 sammanpressade den uppblasta filmen 10 cla denna nadde valsen 28 och forhindrade att luft lackte ut fran den innestangda bubblan. An entrapped air bubble was initially inserted into the portion of the film hose 10 which passed between the rollers 27, 28 and served to successively inflate the film hose 10. A rubber roller 30 which was pressed against the roller 28 compressed the inflated film 10 cla this grafted roller 28 and prevented air leaked out of the trapped bubble.

MeIlan valsarna 27, 28 voro ett par etchtroder 31, 32 placerade pa ett inbOrdes avstand av 1,6 mm, mellan vilka den uppblasta filmen 10 lick passera. Upphlasningen av filmen 10 var sadan, att vaggarna pa. filmen 10 kommo i kontakt med en eirkelbage p5. elektroderna 31, 32 vid passagen genom zonen. Between the rollers 27, 28, a pair of etch rods 31, 32 were placed at a distance of 1.6 mm from each other, between which the inflated film 10 would pass. The loading of the film 10 was such that the cradles on. the film 10 came in contact with an eirkelbage p5. the electrodes 31, 32 at the passage through the zone.

Elektroderna 31, 32 (fig. 7 och 8) utgjordes av tunnvaggigt »Pyre)D (inregistrerat varumarke) glasror, 12,7 mm i diameter, ph insidan belagt med kolloidalgrafit for att bilda ett elektriskt ledande skikt 33. Elektroderna 31, 32 fasth8llos i metallkanaler 34, 35 med tillhj alp av klammor 36 och organen 34, 35 uppburos av andplatar 37, 38. Det kanalformade organet 34 var fast forankrat i platarna 37, 38 i hada andar medan det kanalformade organet 35 var vridbart lagrat med sin nedre dude i platarna 37, 38 medelst svangtappar 39, 40 och forhindrades att falla tillbaka till stoppklackarna 41, 42 genom kulsparrar 43, 44 i urtagen 45, 46 i platarna 37, 38. Den Oppna positionen for elektroden 32 med det till denna hiirande kanalformade organet 35 visas punktstreekat i fig. 8. Stoppklackarna 47, 48 anvandes for att forhindra att organet 35 skulle forskjutas under kulsparrens lage. De nedre andarna pa de kanalformade organen 34, befunno sig pa ett avstand av 4,8 mm fean varandra. The electrodes 31, 32 (Figs. 7 and 8) consisted of thin-walled »Pyre) D (registered trademark) glass tubes, 12.7 mm in diameter, ph inside coated with colloidal graphite to form an electrically conductive layer 33. The electrodes 31, 32 were fixed. in metal channels 34, 35 with the aid of clamps 36 and the members 34, 35 supported by duct plates 37, 38. The channel-shaped member 34 was firmly anchored in the plates 37, 38 in hated spirits while the channel-shaped member 35 was rotatably mounted with its lower dude in the plates 37, 38 by means of pivot pins 39, 40 and was prevented from falling back to the stop lugs 41, 42 by ball joints 43, 44 in the recesses 45, 46 in the plates 37, 38. The open position of the electrode 32 with the channel-shaped member 35 belonging thereto is shown in phantom in Fig. 8. The stop lugs 47, 48 are used to prevent the member 35 from displacing under the position of the ball joint. The lower spirits of the channel-shaped members 34 were at a distance of 4.8 mm from each other.

Med delta arrangemang for att uppbara elektroderna 31, 32 komma klumpar av polyeten eller annat frammande material som medfoljer filmslangen 10 och som liar benagenhet att bloekera oppningen mellan elektroderna 31, 32 att ffinga upp kanten pa det kanalformade organet 35 och fororsaka att kulsparrarna 43, 44 utlosas varigenom organet 35 tillsammans lined elektroden 32 faller tillbaka och pa sâ satt vidgar oppningen melIan elektroderna 31, 32 och varnar skotaren for narvaron av icke onskvart frammande material som medfoljer filmslangen 10. Vid drift anslotos de elektriskt ledande skikten ph elektroderna 31, 32 till en vaxelspanningskalla (50 p/s) pa 12 kV. With delta arrangements for supporting the electrodes 31, 32 come lumps of polyethylene or other foreign material which accompany the film hose 10 and which tend to block the opening between the electrodes 31, 32 to pick up the edge of the channel-shaped member 35 and cause the ball joints 43, 44 is triggered whereby the member 35 together lined the electrode 32 falls back and thus the opening between the electrodes 31, 32 widens and warns the forwarder of the presence of non-adverse foreign material accompanying the film hose 10. In operation the electrically conductive layers ph the electrodes 31, 32 are connected to a alternating voltage source (50 p / s) at 12 kV.

Eventuell statisk laddning p5. ytan av filmslangen 10 avlagsnades med tillhj alp av kon, 6 ventionella statiska eliminatorer 49, 50 omedelbart fore upplindnin.gen pa valsen 29. Filmslangen 10 som upplindades pa valsen 29 visade sig vara fullstandigt fri fran elektrostatiska laddningar och kunde latt 8ppnas utan nagon tendens hos filmen 10 att vilja atertaga det hoppressade tillstandet. Possible static charge p5. The surface of the film tube 10 was removed with the aid of cone, 6 conventional static eliminators 49, 50 immediately before winding on the roll 29. The film tube 10 wound on the roll 29 was found to be completely free of electrostatic charges and could be opened without any tendency to the film 10 to want to recapture the compressed state.

For kontrollens skull upprepades den kontin.uerliga framstallningen av filmslang utan att nhgon spanning palades elektroderna 31, 32. Den erhallna filmen 10 upplindad pa valsen 29 var svar att Oppna och efter att ha Oppnats atertog den sitt tillslutna stadium cla den slapptes. For the sake of control, the continuous production of film tubing was repeated without any voltage being applied to the electrodes 31, 32. The obtained film 10 wound on the roller 29 was in response to opening and after being opened it resumed its closed stage until it was released.

I sa.dana fall cla filmslangen pa ett icke onskvart satt klibbar fast vid elektroderna till foljd av nodvandigheten att anvanda hoga spanningar, kan dragningseffekten pa filmslangen reduceras genom anvandning av fritt roterande elektroder eller fixerade elektroder med fritt roterande elektriskt isolerade reglerhylsor. In such cases, if the film hose is adhered to the electrodes in a non-adherent manner due to the need to use high voltages, the pulling effect on the film hose can be reduced by using freely rotating electrodes or fixed electrodes with freely rotating electrically insulated control sleeves.

Awn can i exemplen endast har refererats till framstallning av polyetenfilmslang, är uppfinningen tillamplig pa flexibel filmslang av andra for elektrostatiska laddningar kan.sliga material, sasom polyamider, polyestrar, cellulosaacetat, polystyren, polyvinylidenklorid, polyvinylklorid, polykarbonat eller liknande material med hog elektrisk isoleringsformaga. Although in the examples only reference has been made to the production of polyethylene film tubing, the invention is applicable to flexible film tubing of other electrostatic charge-capable materials such as polyamides, polyesters, cellulose acetate, polystyrene, polyvinylidene chloride, polyvinyl chloride, high electrostatic polycarbonate or similar insulating materials.

Andra organ an elektroder placerade pa 6m-se sidor om den uppblasta filmslangen kunna anvandas for att alstra elektrostatisk spanning i det gasformiga mediet inuti filmen. Ett par elektroder kunna placeras rid sidan om varandra pa samma sida om den uppblasta filmen eller ocksa kunna elektroderna best& av en serie av frista.ende atskilda element eller delar placerade pa den ena eller hada sidorna av den uppblasta filmen. Vidare kan en enkel elektrod matad med en intermittent hog spanning fran en konventionell Tesla-spole anvandas i omedelbar narhet av eller i kontakt med den uppblasta filmen. Other means of electrodes placed on 6m-s sides of the inflated film tube may be used to generate electrostatic voltage in the gaseous medium within the film. A pair of electrodes may be placed side by side on the same side of the inflated film or the electrodes may also consist of a series of independently separated elements or parts placed on one or both sides of the inflated film. Furthermore, a single electrode fed with an intermittent high voltage from a conventional Tesla coil can be used in the immediate vicinity of or in contact with the inflated film.

Andra anordningar an elektrostatiska falt kunna anvandas for att jonisera det gasformiga mediet inuti den uppblasta filmen, t. ex. ultraviolett ljus med hog energi, rOntgenstralning, bombardering med partiklar med hog energi eller sadana elektriska radiofrekvensimpulser som kunna erhallas fran ett spar i i en vagledare eller rid flagon diskontinuitet i en radiofrekvenstransmissionsledning. Other electrostatic field devices may be used to ionize the gaseous medium within the inflated film, e.g. ultraviolet light with high energy, X-rays, bombardment with high energy particles or such electrical radio frequency pulses that can be obtained from a save in a waveguide or ride flag discontinuity in a radio frequency transmission line.

Claims

Patent claim:

Salt to substantially reduce or eliminate electrostatic charges on the inside of a flexible film hose of a material susceptible to electrostatic charge, characterized in that the film is continuously passed between two different pairs of rollers, that it is inflated between the separate pairs of rollers by means of an enclosed bubble of a gaseous medium, sufficient to expose substantially the entire inside of the film tube to the gaseous medium and that the gaseous medium is ionized inside the film tube to such an extent that electrostatic charges present on the inside of the film tube are substantially electrically neutralized.

2. A kit according to claim 1, characterized in that the gaseous medium is ionized by being subjected to an electrostatic voltage, developed between a pair of spaced apart electrodes, which are placed next to the film hose and fed with an electric alternating voltage of a size sufficient to ionize the gaseous medium but not sufficient to give rise to a spark discharge between the electrodes.

3. A kit according to claim 2, characterized in that the film tube is placed between the electrodes and inflated to such an extent that, in the absence of the electrodes, it would assume a diameter greater than the space between the electrodes, whereby the electrodes are in contact with and partially enveloped by the film hose.

4. A set according to any one of claims 13, characterized in that the film hose is treated while it continuously passes from clamp rollers for film hose in a spray device for film hose to a collecting roller.

5. sat according to some of the preceding patent claims, may be characterized by the fact that the film hose consists of polyethylene.

Device for substantially reducing or eliminating electrostatic charges on the inside of running flexible film hose of a material susceptible to electrostatic charge according to claims 1-5, characterized in that the dies comprise a pair of spaced apart rollers, between which the film hose passes, holding means for holding an entrapped bubble of a gaseous medium trapped within the film tubing between the rollers, a pair of spaced apart electrodes disposed adjacent the running, inflated film tubing and an electric shunt voltage source connected to the electrodes to produce an electrostatic voltage between the electrodes of this size; the gaseous medium inside the film tube is ionized to such an extent that the pH inside the film tube of the existing electrostatic charges is substantially electrically neutralized, but does not sufficiently give rise to a spark discharge between the electrodes.

7. A device according to claim 6, characterized in that the spaced apart pairs of rollers are connected to further rollers so as to form clamping rollers for holding the gaseous medium trapped inside the film hose.

Device according to claim 6 or 7, characterized in that the film hose passes between the electrodes and that the electrodes are rod-shaped and arranged opposite each other on opposite sides of the inflated film hose.

Device according to any one of claims 6-8, characterized in that the electrodes are filled with an electrically insulating material.

Device according to claim 9, characterized in that the usual electrode consists of a piece of glass tube, which is coated on the inside with a layer of electrically conductive colloidal graphite.

Device according to any one of patent claims 6-10, characterized in that the distance between the electrodes amounts to 1.6-6.35 mm.

12. A device according to any one of patent claims 6-11, characterized in that at least a pair of staple rollers are arranged on each side of the lane, which is traversed by the inflated film hose, in order to grip the folded edges of the film.

13. Device according to any one of claims 6-12, characterized in that a control means when registering that too large material parts accompany the film hose causes the electrodes to freeze.

14. Device according to claim 13, characterized in that the control means comprises a pair of completely separate racks, each of which has an electrode and forms one. opening, through which the film hose passes before it passes between the electrodes, whereby at least one of the racks can be pivoted away from the second member which supported the electrode connected thereto when material larger than the width of the opening presses against the rack. Request publications: