SE502759C2

SE502759C2 - Method and apparatus for applying fibers by means of friction charging

Info

Publication number: SE502759C2
Application number: SE9500229A
Authority: SE
Inventors: Raymond Petersson; Kjell K Alm
Original assignee: Seal Flock Ab
Priority date: 1994-03-06
Filing date: 1995-01-24
Publication date: 1996-01-08
Also published as: AU686772B2; KR970701591A; WO1995024272A1; NO302867B1; FI963517A; JPH10511032A; AU1965295A; CN1146167A; SE9500229L; NO963708D0; EP0750527A1; NO963708L; FI963517A0; SE9500229D0; CA2184911A1

Abstract

The invention refers to a method and a device for application of fibres on a base. The probelm that is solved by the present invention is to charge and convey fibres to a surface, on which the fibre is going to be applied, without need of using electrically powered units to generate a high voltage. This is carried out by friction charging of the fibre. This is achieved by using differences in electro-negativity between two materials. The application equipment includes a charging tube (8), through which the fibre is driven. The inside of the charging tube (8) consists of a dielectric material (9), for instance PTFE. This material is strongly electro-negative and therefore tears electrons from materials that have less electro-negativity.

Description

»av I C71 C) 10 15 20 25 30 35 »BJ 759 . x n 2 ytan. Kraftfältets styrka bestäms av mängden laddning. I en kantig partikel som fibern tjänstgör ändarna som elektroder, vilka släpper en del laddning till omgivningen. Därför kommer en kraftigt laddad partikel att avge en del laddning till Detta tyder pà att det finns en mättad laddning som en partikel av en viss form omkringliggande luft, som dä joniseras. kan bära. »Av I C71 C) 10 15 20 25 30 35» BJ 759. x n 2 surface. The strength of the force field is determined by the amount of charge. In an angular particle like the fiber, the ends serve as electrodes, which release some charge to the environment. Therefore, a heavily charged particle will emit some charge to This indicates that there is a saturated charge as a particle of a certain shape surrounding air, which is then ionized. can carry.

Föreliggande uppfinning avser sàledes ett förfarande för applicering av fibrer pà ett underlag, vid vilket underlaget förses med ett adhesiv och fibrerna ges en elektrisk laddning genom friktion mot ett dielektriskt material och riktas mot underlaget. Uppfinningen avser ocksa att det dielektriska materialet är anbragt pá en yta av ledande material som genom en jordledning är förbunden med jord och att den elektriska ström som flyter i jordledningen mäts och utgör ett matt pà mängden fibrer som laddats och att denna ström utnyttjas för att styra mängden fibrer som tillsätts sa att denna blir den avsedda. Den tillsatta fibermängden kan därvid regleras med hjälp av en doseringsanordning och en fläktanordning.The present invention thus relates to a method for applying fibers to a substrate, in which the substrate is provided with an adhesive and the fibers are given an electric charge by friction against a dielectric material and directed towards the substrate. The invention also relates that the dielectric material is applied to a surface of conductive material which is connected to earth through a ground wire and that the electric current flowing in the ground wire is measured and forms a mat on the amount of fibers charged and that this current is used to control the amount of fiber added so that it becomes the intended one. The amount of fiber added can then be regulated by means of a dosing device and a fan device.

Uppfinningen avser även en anordning för applicering av fibrer pà ett underlag, vilken innefattar minst en yta av ett dielektriskt material mot vilken fibrerna riktas med hjälp av en doseringsanordning och en fläktanordning och att de genom friktionen elektrisk laddade fibrerna riktas mot underlaget.The invention also relates to a device for applying fibers to a substrate, which comprises at least one surface of a dielectric material to which the fibers are directed by means of a dosing device and a fan device and that the fibers electrically charged by the friction are directed towards the substrate.

Denna kan vara sa utförd, att det dielektriska materialet är anbragt pá minst en yta av ledande material som genom en jordledning är förbunden med jord och att den elektriska ström som flyter i jordledningen mäts och utgör ett matt pá mängden fibrer som laddats och att denna ström utnyttjas för att styra mängden fibrer som tillsätts med hjälp av doseringsanordningen och fläktanordningen sa att mängden blir den avsedda.This can be designed in such a way that the dielectric material is applied to at least one surface of conductive material which is connected to earth through a ground wire and that the electric current flowing in the earth wire is measured and forms a mat on the amount of fibers charged and that this current is used to control the amount of fibers added by means of the dosing device and the fan device said that the amount becomes the intended one.

En utföringsform av föreliggande uppfinning visas schematiskt pa ritningen, där figur 1 visar den principiella uppbyggnaden av en anordning enligt uppfinningen, och 10 15 20 25 30 35 ,- 502 759 ° 3 figur 2 visar funktionen hos ett appliceringsmunstycke.An embodiment of the present invention is shown schematically in the drawing, where figure 1 shows the basic structure of a device according to the invention, and figure 2 shows the function of an application nozzle.

Som framgår av figur l är en fläkt l anordnad att avge ett luftflöde 2 till en doseringsanordning 3 för fibrer som kan vara anordnad med en behållare 4 från vilken fibrerna tas. luftflöde 5 innehållande fibrer till appliceringsanordningen 6, fibrerna laddas elektrostatiskt så att ett flöde 7 av luft med laddade fibrer avges. Av figur 2 framgår att det andra luftflödet 5 med huvudsakligen oladdade fibrer i appli- Doseringsanordningen 3 avger ett andra i vilken ceringsanordningen riktas mot en yta 9 av en exempelvis rör- formad del 8 av metall, varvid ytan 9 är belagd med PTFE eller annat material som ger fibrerna i flödet 7 elektrisk laddning. jordledningen 10, i vilken strömmen mäts genom mätanordningen Delen 8 av metall är kopplad till jord genom 11. Värdet på den uppmätta strömmen utgör ärvärde för en styranordning 12, som beroende på detta och ett inställt börvärde avger reglersignal till doseringsanordningen 3 och ev. även till fläkten 1.As can be seen from Figure 1, a fan 1 is arranged to deliver an air flow 2 to a dosing device 3 for fibers which can be arranged with a container 4 from which the fibers are taken. air flow 5 containing fibers to the application device 6, the fibers are electrostatically charged so that a flow 7 of air with charged fibers is delivered. Figure 2 shows that the second air flow 5 with substantially uncharged fibers in the applicator Dosing device 3 emits a second in which the curing device is directed towards a surface 9 of, for example, tubular part 8 of metal, the surface 9 being coated with PTFE or other material which gives the fibers in the flow 7 electric charge. the earth line 10, in which the current is measured through the measuring device The metal part 8 is connected to earth through 11. The value of the measured current is the actual value of a control device 12, which depending on this and a set setpoint emits control signal to the dosing device 3 and possibly also to the fan 1.

Adhesivet som utnyttjas för att fibern skall fastna på underlaget år ofta ett tvåkomponents hartslim och fibrerna är vanligen syntetfiber av exempelvis polyamid. De fibrer som kan komma i fråga för föreliggande uppfinning är emellertid icke begränsade till någon speciell typ, utan även exempelvis kolfibrer, glasfibrer eller liknande kan komma i fraga.The adhesive used for the fiber to adhere to the substrate is often a two-component resin adhesive and the fibers are usually synthetic fibers of, for example, polyamide. However, the fibers which may be considered for the present invention are not limited to any particular type, but also, for example, carbon fibers, glass fibers or the like may be considered.

Den fibertäthet, med vilken applicering enligt föreliggande uppfinning normalt utförs, kan uppgå till 50-300 fibrer per kvadratmm, företrädesvis mer än 150 fibrer per kvadratmm, med en fibertjocklek mindre än 0,1 mm, företrädesvis mindre än 0,05 mm och en längd uppgående till 0,5-5 mm, företrädesvis mindre än 3 m.The fiber density with which application according to the present invention is normally carried out can amount to 50-300 fibers per square mm, preferably more than 150 fibers per square mm, with a fiber thickness of less than 0.1 mm, preferably less than 0.05 mm and a length amounting to 0.5-5 mm, preferably less than 3 m.

Uppfinningen är icke begränsad till de ovan nämnda utföringsformerna utan den kan varieras på olika sätt inom patentkravens ram.The invention is not limited to the above-mentioned embodiments, but it can be varied in various ways within the scope of the claims.

Claims

502 759 _ lO 15 20 25 30 35 _ 4 PATENT CLAIMS

Method for applying fibers to a substrate, characterized in that the substrate is provided with an adhesive and that the fibers are given an electric charge by friction against a dielectric material and directed towards the substrate.

Method according to claim 1, characterized in that the dielectric material is applied to a surface of conductive material which is connected to earth through a ground wire and that the electric current flowing in the earth wire is measured and constitutes a measure of the amount of fibers charged and that this current is used to control the amount of fibers added so that it becomes the intended one.

Method according to claim 2, characterized in that the amount of fiber is determined by a dosing device and a fan device.

Method according to one of Claims 1 to 3, characterized in that the fibers have a length of between 0.5 and 5 mm and are applied with a density of up to 50-300 fibers per square mm.

Device for applying fibers to a substrate, characterized in that it comprises at least one surface of a dielectric material against which the fibers are directed by means of a dosing device and a fan device and that the fibers electrically charged by the friction are directed towards the substrate.

Device according to claim 5, characterized in that the dielectric material is applied to at least one surface of conductive material which is connected to earth through a ground wire and that the electric current flowing in the ground wire is measured and constitutes a measure of the amount of fibers charged and that this current is used to control the amount of fibers added by means of the dosing device and the fan device so that the amount becomes the intended one. »\ W 502 759 5

Device according to one of Claims 5 and 6, characterized in that the fibers have a length of between 0.5 and 5 mm and are applied with a density of 50-300 fibers per square mm.