US3065787A - Apparatus for the production of webs of fibre material - Google Patents

Description

Nov. 27, 1962 K. RESCHENEDER 3,065,787

APPARATUS FOR THE PRODUCTION OF WEBS OF FIBRE MATERIAL Filed July 13, 1960 2 Sheets-Sheet 1 Iran/enter K.H68C12/ezbeder Filed July 13, 1960 Nov. 27, 1962 K. RESCHENEDER 3,065,787

APPARATUS FOR THE PRODUCTION OF WEBS OF FIBRE MATERIAL 2 Sheets-Sheet 2 Unite rates 3,065,787 APPARATUS FOR THE PRQDUCTIQN F WEB 0F FIBRE MATERIAL Karl Rescheneder, Voeirlahruck, Austria, assignor to Eternit-Werke Ludwig Hatschek, Vocklahruclr, Austria Filed July 13, 1960, Ser. No. 42,723 Claims priority, application Austria July 14, 1959 Claims. (Cl. 162-327) The invention relates to an apparatus for the production of webs of fibre material, especially asbestos cement webs, using a cylinder mould machine or other webforming machines in which an alignment of fibres in the direction of motion of the Web carrier is effected by the motion of said web carrier.

It is a well known fact that webs of fibre material are usually produced on cylinder mould machines or other web-forming machines such, for example, as those in which the pulp is drawn by a suction chest, over which a felt slides. This processing of fibre material entails various disadvantages however.

Thus the reinforcing fibres are combed out by the rotating cylinder or a moving felt serving as a web carrier and are laid parallel to the direction of motion. The higher the angular velocity and hence the working speed, the more the fibres are straightened. This combed-out layer of fibres, which are straightened at one end, results in relatively considerable strength differences in a position normal and parallel to the direction of production, and this is undesirable especially in the case of sheets of fibre material. In order therefore to improve the flexural tensile strength which is considerably lower in the direction parallel to the direction of the Web of material, it was hitherto necessary to use an increased fibre charge and this means an increase in the costs of raw material.

There has been no lack of attempt to obviate this drawback by bringing the fibres in a crossed position in relation to one another. There has not, however, hitherto been any satisfactory technical solution to this prob lem. Methods known heretofore, for example, comprise the use of various means in the stock of cylinder box to produce a flow extending in the direction of the cylinder axis. The results obtained are, however, very modest and the fiexural tensile strengths obtained in the parallel direction to the web hardly approach the strength values that can 'be obtained in the position normal (transversely) to the fibre, because the entire box filling is set in motion and the necessary speed of flow of the stock circulation can be obtained only with difiiculty, especially in the case of high-speed machines. advantage of these processes is the destruction of the freeness of the stock, as is very important for good production, because the pulp, which is constantly kept in circulation in its entirety, whether by pumps or other devices, becomes greasy through an excess of preparation,

consequently drains badly, interferes with the operation of the clarifying devices, and has a very adverse effect on manufacturing conditions. For this reason, none of these processes has become established on an industrial scale.

It has also already been proposed that a set of plates,

consisting of approximately vertical plates disposed side by side at small distances from one another should be Another considerable distion of the fibres. The movement can only remain a moderate one, the level of the material fluctuating between the two end faces of the cylinder box, according to the size of the set of plates and their speed. The preferential direction of the fibres as determined by the cylinder motion can be influenced only to a minor extent. Moreover, during the change of the stroke a neutral zone forms in which the direction of the fibres is again determined practically only by the direction of motion of the cylinder, even if only for a short time. The reciprocating motion and the resulting continual change of level also make it difiicult to keep the flow uniform over the entire Working width.

The attempt has therefore also already been made to influence the fibre direction by means of rotating agi tators. According to a known proposal in this direction, numerous agitators disposed in parallel relationship to the cylinder mould axis are provided approximately in the centre between the cylinder and the stock box wall. Although this produces a regular loop motion of the stock with its branches situated between the agitators and the cylinder or the container wall, the deflection from the tangential fibre direction that can be obtained with it is very small. It is also obvious that the effect of the large number of agitators in this arrangement is not very considerable. A slow agitator movement gives very little result and a rapid movement would completely destroy the desired looping motion of the material. Apart from the complex nature of the apparatus, which renders necessary a large number of journals which are taken out of the cylinder box and Which have to be sealed, it can be used only with very light substances which do not tend to sink, such as occur in the paper industry. Such an arrangement could not be used in the, fibre cement industry, since the heavy suspended matter is not whirled up.

The above disadvantages are obviated in the apparatus equipped with rotary agitators according to the invention, by the fact that the agitators, which are combined to form at least one insert, are disposed preferably close together and rotatably about axes which are approximately tangential, especially perpendicular, to the cylinder mould and are situated advantageously in the absorptive zone of the web carrier, for example near the cylinder mould or the moving felt.

The rotation of agitators disposed in this manner gives a horizontal alignment of the fibres, the individual fibres coming on to the mould at a greater or lesser angle in dependence on the agitator speed which is, for example controllable. The apparatus according to the invention has the effect that only the material situated directly at the absorptive region of the web carrier is subjected to any influencing. Moreover, an absorption-promoting effect is achieved by centrifugal force, which throws the material against the cylinder mould or the moving felt.

Practical tests on the apparatus according to the invention have shown a hitherto unattainable increase of the flexural tensile strength of the resulting fibre web parallel to its direction of motion without any appreciable drop in the strength transversely to the direction of motion. This is due on the one hand to the fibre arrangement achieved and on the other hand to the fact that the twirling motion produced directly by the web carrier precludes any nest formation in the fibre material.

It has proved advantageous to make the insert movable transversely to the direction of motion of the web carrier, for example in the direction of the longitudinal axis of the cylinder mould, since a reciprocating motion of the insert, preferably by about half the width of the agitators, prevents any striation at the neutral regions of the fleece during the production process.

In order to restrict the twirling motion of the fibres to the immediate region in front of the web carrier, the individual agitators of the insert may be disposed in chambers which are open towards the web carrier. The agitators are advantageously equipped with straight or, for example, S-shaped blades. The blade spindles of the agitators may be extended in the downward direction and carry at their lower ends propeller-like or screw-like devices which drive the pulp upwards and hence prevent the material from sinking in the case of a particularly thick consistency.

The drawing illustrates one exemplified embodiment of the apparatus according to the invention.

FIG. 1 is a diagrammatic view of a part of a cylinder mould machine equipped with the apparatus according to the invention, and FIG. 2 is a side view of a single agitator.

FIGS. 3, 4, and 6 show further embodiments and details, respectively, of the apparatus according to the invention.

Reference 1 denotes the cylinder box which serves to receive the fibre material and in which is situated the cylinder mould 2, from which the fibre web formed is removed by means of the couch roll 3 and the conveyor felt 4. The insert 5 is disposed near the cylinder mould and comprises a plurality of individual agitators 6. The level of liquid outside the cylinder mould is denoted by reference a and the level inside the said mould is denoted by b.

The absorption of the pulp by the cylinder mould is eifected immediately after the empty mould dips into the pulp. As soon as the meshes of the mould have been closed by a layer of pulp the absorption of the cylinder is practically completed. According to the invention, therefore, the direction of the fibres is influenced at this point without the flow of the remaining filling of the cylinder box being in any way effected.

The abovementioned horizontal fibre alignment is formed by the said agitators which have, for example, perpendicular rotating blades.

The agitators are equipped with rectangular straight blades 7 or S-shaped blades 8, which are driven by a common driving shaft 9. Semi-cylindrical guard plates are illustrated in front of some of the agitators on the side remote from cylinder mould 2, so that the action of the agitators is restricted to the region directly in front of the cylinder mould. The complete insert 5 is capable of reciprocating in the direction of the longitudinal axis of the cylinder mould 3. The speed of this motion may be controllable.

The agitator 6 shown in FIG. 2 carries not only the blades 7 but also, on downwardly extended spindle, a propeller 19 which prevents the fibre materials from sinking.

A plurality of inserts may be provided at the periphery of the cylinder mould. The construction illustrated, however, has the advantage that the driving mechanism 11 of the agitators can be disposed outside the pulp.

The blades may also run in the cylinder box without any screening.

FIG. 3 shows an arrangement including electric motor M as the driving means and an infinitely variable gear 12 for regulating the rotational speed of the agitators 6 by means of the shaft 9.

According to FIG. 4 an eccentric 13 is provided which is actuated by a drive 14 over a belt or a chain 15. This eccentric permits the infinitely variable gear .12 as well as the insert 5 cooperating therewith the reciprocating motion above mentioned.

When a plurality of web-forming means are used, for

example multi-cylinder machines, the direction of rotation of the agitators in the successive boxes-as illustrated in FIG. 5may be opposed to one another so that a crossing of the fibres is obtained.

In FIG. 5 such a device with three series-connected cylinder boxes is illustrated.

The speeds of the individual agitators of one and the same insert may be made different in order to achieve diiferent strength zones in the webs of fibre material. This can be attained, as shown in FIG. 6 of the drawing, by means of infinitely variable gears 16 known per se which are interpositioned between the shaft 9 and each individual agitator 6.

What I claim is:

1. In an apparatus for producing fibre webs, particularly asbestos cement webs, a container for fiber material, cylindrical web forming means mounted in the container, movable web carrier means cooperable with said cylindrical web forming means so that movement of the web carrier means effects an alignment of the fibres in the direction of movement of the web carrier means and means for avoiding unilateral alignment of the fibres, said last-named means including a plurality of rotatable agitating means, means mounting said rotatable agitating means in said container in closely spaced apart relationship in a direction transverse to said cylindrical web-forming means for rotation about axes substantially tangential to said cylindrical Web-forming means, and drive means for rotating said agitating means.

2. An apparatus as claimed in claim 1, further including means for reciprocating said agitating means transversely with respect to the direction of movement of the web carrier means while said drive means rotates said agitating means.

3. An apparatus as claimed in claim 1, including means for regulating the speed of rotation of the agitating means.

4. An apparatus as claimed in claim 2, including means for regulating the speed of reciprocation of said agitating means.

5. An apparatus as claimed in claim 3, including infinitely variable gear means for rotating the agitating means.

6. An apparatus as claimed in claim 1, further including wall means defining a chamber for each agitating means with each chamber being open in a direction facing the web carrier means.

7. An apparatus as claimed in claim 1, in which each agitating means includes a fiat blade-like body.

8. An apparatus as claimed in claim 1, in which each agitating means includes an S-shaped blade-like body.

9. An apparatus as claimed in claim 1, in which each agitating means includes a blade-like body, a spindle for the body extending beyond the lower end of the body, and a propeller-like component on the extended portion of the spindle.

10. An apparatus as claimed in claim 1, including infinitely variable gear means for each agitating means for rotating the agitating means at different speeds whereby the influencing of the fibre deposit is variable in the zones wf the various agitating means.

References Cited in the file of this patent UNITED STATES PATENTS 1,771,600 Yoder July 29, 1930 1,808,055 Millspaugh June 2, 1931 2,216,817 Kutter Oct. 8, 1940 2,304,735 Leeson Dec. 8, 1942

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