IL43328A - Process and apparatus for manufacturing glass fibre mats by winding - Google Patents

Description

Process and apparatus for manufacturing glass fibre mats by winding TAMIS LTD C/ 41151 This invention relates to an improved process and apparatus for manufacturing glass fibre mats. Such glass fibre mats consist of a plurality of superimposed layers of glass fibres and are. generally employed after impregnation with a suitable bonding agent for insulating purposes.

A known process for manufacturing glass fibre mate (hereinafter referred to as a process of the kind specified) see e-rg. French Patent No. 1,357,859 /comprises the steps of renderin glass molten in a tank, drawing from an apertured base of the tank a row of molten glass ^fibres of extent l^, winding said row of fibres on a drum of length l^ which is rotatable about a horizontal axis and reciprocatably displacing the tank and said row in a direction parallel to the axis with a stroke l^ wherein lg^ l^ ♦ l^.

In general, and with a process of the kind specified, successive layers of glass fibres are wound onto the drum.

When the required number of glass fibre layers have been wound onto the thus coated drum the drawing of the fibres and the rotation of the drum is interrupted and the cylindrical glass fibre shell is slit along a generatrix thereof and the rectangular glass fibre element is detached from the drum and is generally folded or roiled about a side thereof which is equal in length to the peripheral circumference of the drum.

In order to form the mats, the rectangular element is manually unfolded and the glass fibre portion thereof is manually stretched by a predetermined amount and passed for subsequent impregnation. When the stretching and impregnation of one element is about to be completed, the procedure is r^-interrupted and the adjacent edge of a successive elemn ^ is joined to the trailing edge of the element already stretched and the procedure is then restarted. Thus, the time period during which stretching and impregnation of an element can proceed without interruption is determined by the length of the element which corresponds to the length of the drum on which the element has been wound. Thus, the shorter the drum the shorter the length of the element and the greater the interruptions required for joining the edges of successive elements together.

With a process of the kind specified and in view of the fact that the glass fibre row is of a finite and indeed substantial extent (l^) the length of the glass fibre element wound on the drum cannot be of uniform thickness and at each end of the drum the thickness will in fact taper over a length l^ from a minimum at the end of the drum to a maximum,corresponding to the uniform thickness of the central portion of the element, at a distance l^ from the end of the drum. These non-uniform end portions cannot be used in the formation of the mats and must be ranoved from the elements prior to stretching, impregnation and coupling. Thus, with an element of a predetermined length a significant proportion thereof r.ust be discarded at the very outset and this leads to increases in production costs and time.

It Is therefore an object of the present invention to provide a new and improved process for producing glass fibre mats of the kind specified in which the above referred to disadvantages are substantially reduced.

According to the present invention there is provided a process of the kind specified for manufacturing glass fibre mats comprising the steps of drawing two collinear rows of molten glass fibres each of extent l^ which are spaced apart by a fixed distance l^, reciprocatably displacing said rows in a direction parallel to the axis of the winding drum of length l, with a stroke l^, where l^ is substantially equal to ^+l^ end where 1*2 ^ 21^+1^.

With the process in accordance with the present invention the two rows of glass fibres are wound on a drum which is of substantially greater length (at least twice as long) than the drum used in accordance with the known process of the kind specified. By virtue of the reciprocating motion of the spaced apart rows in accordance with the present invention the tapering portion wound from a first row at the end of its stroke at the mid-point of the drum is supplemented by the corresponding tapering portion wound by the second row at the beginning of its stroke at the mid-point of the drum. In this way the glass fibre layers at the mid-point of the drum are substantially equal in thickness to the layers on either side of the mid-point. Only the end portions of the drum are covered with non-uniform tapering layers.

If now the drum used with the process in accordance with the invention is twice the length of the drum used with a conventional process of the kind specified the useful length of a glass fibre element, i.e., the length of uniform thickness produced with a double length drum of the process in accordance with the present invention is 2^ - 21^. When this is compared with the useful length of two elements produced with a drum of half the length in accordance with the conventional process this length is It can thus be clearly seen that the element produced in accordance with the present Invention has It Is thua obvious that the process in accordance with the present invention leads to very considerable ' economies in terms of material and time and furthermore by virtue of the fact that longer lengths of elements are involved less time interruptions need be taken into acoount when the elements have to be joined together to form the mats as described above.

In accordance with a specific aspect of the present invention there is provided apparatus for carrying out the process in accordance with the present invention comprising tank means within which glass can be rendered molten, means for drawing two rows of glass fibres spaced apart by a fixed amount from said tank means and means for reeiprocatably displacing said tank means with a predetermined stroke.

For a better understanding of the present invention and in order to show how the same may be carried out in practice reference wil now be made to the accompanying drawings in which Figs, la and lb show schematically two dentical sete of known apparatus for producing glass fibre mats in a known manner,.

Pigs, 2a and 2b are cross-sectional views of the drums shown in Pigs,, la and lb taken along the lines tla-IIbj Ilb-IIb, ig.s 3 shows schematically apparatus for producing glass fibre mats In accordance with the present invention when carrying out the process in accordance with the invention, and Pigs, 1 and 2 illustrate the use of conventional apparatus and method in producing glass fibre elements f * use in subsequently forming glass fibre mats. A melting tank 1 is displaceable on an overhead rail 2 and is fed with glass for melting via a hopper 3 located below the tank 1 and rail 2 is a horizontally disposed drum 4 (of length 2) which is rotatable (by means not shown) about a horizontal axle %, Drawn from the tank 1 is a row of glass fibres 6 of extent l^. As the drum rotates the tank is reciprocated, with respect thereto with a stroke l^ such that 12 l^ +■ l^.

It can readily be seen from Figs. 2 of the drawings, that the glass fibre element wound on to the drum has a length, substantially equal to lg but which has portions of nonuniform thickness of length 21^. If now as seen in the drawings 2 such elements (Figs. 2a and 2b) are formed, the portions of non-uniform thickness of a pair of elements of total length 21g are of length 41·^ and these non-uniform thickness portions are not useful in forming the glass fibre mats and must be discarded.

If now we consider the arrangement shown in Pig, 3 of the drawings we have here a pair of identical melting tanks la and lb, rigidly coupled together by means of a coupling lc and displaceable by means not shown on an overhead rail 2.

The tanks la and lb are respectively fed with glass for melting via hoppers 3a and 3b. Located below the tanks la and lb and the overhead rail 3 is a horizontally disposed drum 4* which is rotatable by means not shown about a horizontal axle 5' .

Drawn from each tank is a row of glass fibres^.' of extent l^, the tanks being so coupled together that the rowe of glass fibres 6' are spaced apart by a distance l^. With the glass fibres drawn from the tanks and wound around the drum, the tanks la and lb are reciprocatably displaced to the right and to the left from the full line positions to the broken line positions shown in the drawings. The displacement stroke of the tanks is 1,-and where the length of the drum is l'g it can be seen that T*2 Is substantially equal to 21,- + 1'^.

As can be clearly seen from the drawings and in particular Fig. 4 thereof, the row 6· of glass fibres originatin from the tank la will result in the winding, on the left hand half of the drum 4' , of an element which has a central portion of length l^ of uniform thickness bordered o either end with tapering portions of length 1·^. Similarly the glass fibre row 6* emerging from the tank lb forms the basis of an element formed on the righthand end of the drum of similar constitution. The two tapering portions located in the mid-portion of the drum compelement each other so as to constitute a region of thickness which is uni orm and equal to that of the regions on either side thereof.

Thus, as explained above there is produced by this method a glass fibre element which can subsequently be formed into a lass fibre mat which has a length l 2 greater than (in this specific case double) the length of the drum 19 used i accordance with the conventional process. With such a double lengt element however only the end portions thereof of length ^ have to be discarded whilst the mid-portion is perfectly usable. In this way the element produced in accordance with the present invention includes substantially less (21g) waste material than two equivalent elements formed by a conventional method with a drum of conventional length.

It will be realised that whilst theoretically the same results could be achieved by using a single tank displaceable over a elongated drum with a stroke double the stroke of the tanks in accordance with the present invention the time Involved in reciprocating such a tank would be so considerable as to render the process entirely uneconomical.

Whilst the invention has been specifically described using two coupled together tanks and a drum of length double that of a conventional drum it will be appreciated that more than two tanks can bo employed with drums of lengths other than double the length of the conventional element.

Furthermore, whilst in the specific embodiment described above two conventional tanks have been used coupled together a single tank can be employed with means for drawing therefrom two rows of glass fibres spaced by the required amount·

Claims (5)

1. A process of the kind specified for manufacturing glass fibre mats comprising the steps of drawing two collinear rows of molten glass fibres each of extent l^ which are spaced apart by a fixed distance l^, reciprocatably displacing said rows in a direction parallel to the axis of the winding drum of length l^ with a stroke l^, where lj is substantially equal to 1^+1^ and where l^ ^ 21^+1^.

2. A process of the kind specified substantially as hereinbefore described by way of example and with reference to the accompanying drawings.

3. Apparatus for carrying out the process according to Claim 1 comprising tank means within which glass can be rendered molten, means for drawing two rows of glass fibres, spaced apart by a fixed amount, from said tank means and means for reciprocatably displacing said tank means with a predetermined stroke.

4. Apparatus according to Claim 3, wherein said tank means comprises a pair of tanks coupled together so as to be displaceable as a single unit.

5. Apparatus for carrying out the process according to Claim 1 substantially as hereinbefore described by way of example and with reference to the accompanying drawings. BENJAMIN J. BARISH Advocate, Patent Attorney, P.O. Box 23008, Tel Aviv, ISRAEL.