US2417375A

US2417375A - Apparatus for producing seamless hollow bodies of felted fibrous material

Info

Publication number: US2417375A
Application number: US476026A
Authority: US
Inventors: Newbould Maurice George Robert
Original assignee: PAPERCRETE Ltd
Current assignee: PAPERCRETE Ltd
Priority date: 1942-03-06
Filing date: 1943-02-15
Publication date: 1947-03-11
Anticipated expiration: 1964-03-11

Description

Marcl1 11,1947. MQRNEWBOULD ,4 7, 7

APPARATUS FOR PRODUCING SEAMLESS HOLLOW BODIES OF. FELTED FIBROUS MATERIAL A Filed Feb. 15, 1943 A 4 Sheets-Sheet 1 "Fig 1a.-

. gGlzhfliembould, a

J1 r M March 11, 1947.

M. G. R. NEWBOULD 9417, 375 APPARATUS FOR PRODUCING SEAMLESS HOLLOW BODIES OF FELTED FIBROUS MATERIAL Filed Feb. 15, 1943 4 Sheets-Sheet 2 March 11, 194-7. m .R. NEWBO U 2,417,375

' APPA ilgII-lJLow .G RATU OR PRCDUCING SEA SS BODIES OF FELTED FIBROUS MATER Filed Feb. 15, 1945 4 Sheets-Sheet 3 March 11, 1947. M. G. 2,417,375

APP TUS FOR RIJ-ZIXIELOW I ESS TE R. NEWBOULD PROD ING SEAML D ES OF FELTE I ROUS MA Filed Feb. 1943 4 Sheets-Sheet 4 Patented Mar. 11, 1947 APPARATUS FOR PRODUCING SEAMLESS HOLLOW BODIES OF FELTED FIBROUS MATERIAL Maurice George Robert Newbould, London S. W. 1, England, assignor to Papercrete Limited,

London, England Application February 15,1943, Serial No. 476,026

In Great Britain March 6, 1942 Claims.

This invention relates to the production of hollow bodies of felted fibrous material by the aspiration of a fluent fibrous pulp against the surface of a foraminous member.

The processes for the manufacture of seamless hollow bodies in the manner above referred to may broadly be divided into two classes, namely, (a) that in which the fluent fibrous pulp is introduced within a foraminous mould with which may be associated an expansible and contractable core element, the extraction from the mouldof the body formed by the felted mass of deposited the core element and carried by the outer mould materia1 being effected by causing it to contract,

and (b) that in which the fibrous component of a fluent fibrous pulp is deposited on a foraminous core element which in certain cases has been arranged so that it may be expanded and. contracted, the outer mould element in such case being a rigid non-foraminous member or a member comprising a plurality of sections adapted to be moved toward and away from the body formed on the inner mould element.

The object of the present invention is to provide an improved process of and apparatus for forming seamless hollow bodies by the deposition of the fibrous component of a fluent fibrous pulp on the outer surface of a foraminous core element co-operating with an outer expansible non-foraminous mould element or overform.

According to the invention. the body formed by the deposition of the fibrous component of the fluent fibrous pulp on the foram nous core element is subjected to compression and is thereafter expanded or distended to free it from the core element and is transported by the outer mould element or overform which is correspondingly expanded to a position where the felted mass of fibrous material may be dried or further treated, after it has been freed from the outer mould or overform as the result of its further expansion.

Normally after the fluent fibrous pulp has been deposited on the foraminous core element, a considerable proportion of the residual water contained in the deposited layer of fibrous component is removed by aspiration of air through the fibrous material deposited on the inner mould element.

Apparatus according to the invention comprises an outer non-foraminous mould element or overform so constructed and arranged that it may be contracted to consolidate the felted mass of fibrous material deposited on the core element and thereafter expanded to a degree sufficient to enable the felted mass to be freed from element" or overform to, and deposited by the further expansion or distension of the overform which frees or detaches the felted mass from it, at the position wherethe felted mass of fibrous material may be dried or further treated.

Preferably, in accordance with the invention, the outer non-foraminous mould element is so construcmd and arranged that it may be expanded and contracted by producing a difierence in the pressure operating on its inner and outer surfaces. 7

Thus, in accordance with the invention, the outer non-foraminous mould. element may be formed mainly of a flexible or elastic material such as rubber provided with reinforcements adapted to restrict its distortion without restricting its expansion or distension and may be secured w thin a chamber furnished with connections whereby the pressure between the walls of the chamber and the flexiblenon-foraminous mould element may be varied in order to, effect or permit of its expansion and contraction.

As above indicated, two degrees of expansion are provided for and any appropriate means may be employed to limit the degree of expansion to enable the article formed of the felted mass of fibrous material to be detached from the foraminous core element and to be supported by the outer mould element so that it may be carried to the place where the formed body is to be dried or further treated, and thereafter to be expanded in order that the outer mould element may be freed from the formed body.

For controlling the expansion and limiting the distortion of the outer flexible mould element, it may be provided witha plurality of spaced se mental elements of relatively rigid material extending from a position adjacent to its top, and

with each of these members there may be pivotally connected at two or more points in its length and thus at two or more zones in the height of the outer flexible mould element levers in turn pivotally connected with the outer rigid casing, the outer ends of the levers positioned at each of the zones being connected together by, for instance, a ring with which is associated a ram or rams operating in a cylinder or cylinders connected with a reservoir into which and from which water will be displaced in the expansion sired distortion, a disc preferably faced with Wire gauze may be associated with the upper end of the flexible mould element, the disc bein'g pro-' vided withan extension slidable in guides provided in the casing or chamber with which the flexible mould element is associated.

I To assist in freeing the body of felted fibrous material'from the foraminous core element means may-be'provided for introducing air under pressure into the core element and to assist in detaching, the formed body of felted fibrous material from the outer mould element or overform means may be provided for introducing air under pressure between the surface of the formed body and the inner surface of the outer mould element or-overform.

To retainthe body of felted fibrous material in position in the outer mould element or overform in order that the body may be carried by the mould element'to its position for further treatment, meansmay be provided for producing a pressure below atmospheric pressure between the formed body and the surface of the disc forming the end of the outer mould element or overform in contact with it, in which case the connection with the means for producing the reduced pressure will be interrupted at anappropriate time to enable theformed body of felted fibrous material to become detached, air under a pres sure in excess of atmospheric pressure being normally thereafter introduced between the surface of the formed body and the surface of the inner mould element or overform to assist in detaching the formed body from the flexible outer mould: element which will be distended to its maximum extent to facilitate such detachment and to enable it to be again brought into position over the core element after the stuff chamber has been recharged with pulp and a further body formed of fibrous pulp has been deposited upon the foraminous core.

To enable the outer mould element to be moved into position with respect to the core element for compressing the hollow body and to be removed from this position taking with it the formed body, the outer mould element may be associated with means for lowering it into position for the moulding operation, and thereafter moving it into a position in which the article is to be deposited or detached from the outer mould element or overform for further treatment.

Such means may comprise a crane or the like. The connection of the outer mould element with the crane or the like may be associated with means for releasably locking the outer mould element against the seating provided on the base of the foraminous core element. 1

The connection may, for example, comprise spring urged toggle links so arranged that when the outer mould element is in position over the foraminous core element, the toggle levers will move about their connections to cause link ele- 4 ments associated with them to engage in recesses provided in an extension of the chamber into which the fluent fibrous pulp is introduced and in which is contained the foraminous core element, the stuff chamber being provided with means for introducing the fluent fibrous pulp and an overflow arranged at an appropriate height to ensure that the pulp, when introduced, does not exceed the desired level, means for withdrawing at appropriate times the excess of pulp and means for draining away the water passing through the foraminous core element and optionally drawing air through the body of felted fibrous material formed thereon. V V

The foraminous core element may be secured to a base providing a seating for the lower edge of the chamber with which the outer mould element is associated in order that a gas and liquidtight joint may be secured between the outer mould element and the base on which theforaminous core element is secured.

The base of the foraminous inner core element will normally be located in a'stuff chest, that is to say, a chamber'into which the fluentmass of fibrous material is introduced and atrthe upper endof this chamber means may be provided as above indicated for locking the outer mould element into position so that its lower end will be firmly. engaged on the seating.

The invention will be described further. in detail and by way of example with reference to the construction shown in the accompanying draw ings, in which:

Figures 1a and 1b are respectively composite views in sectional'elevation showing the various working parts. v V

Figures 2a and 2b are respectively a left-hand half section and a right-hand halfsection on a plane indicated by the line A-A in Figure 1a, one half showing certain elements inone position, and the other half showing the elements in another position.

Figure 3 is a vertical cross section on a plane,

indicated by the line BB in Figure 2b.

The construction illustrated comprises essentially a stuff chamber I into which the fluentfibrous pulp is introduced by way of an inlet 2 at the base of the chamber which adjacent to its upper portion is furnished with an overflow3 at an appropriate height above the upper end of the foraminous core element which is secured to a base provided within the chamber.

The core element comprises an inner member 4 extending from the base 5 to a position close to the top of the core element, the purpose of which is to limit or reduce'the free space within 7 the core element.

In the construction illustrated, the inner member 4 is a vessel open at its upper end and in operation of the apparatus it will become filled with the water separating from the pulp and thus, in

efifect, will operate as a solid member in limiting or reducing the free space'within the core ele- V In operation, the, outer mould being raised, the fluent fibrous pulp will be introduced into the stuif chamber through a. stuff inlet pipe 2. The water component of the pulp will pass through the wire gauze covering of the inner mould ele-- ment, and its suspended fibres will be deposited on the exterior surface thereof.

This water is, however, not allowed to pass away through the opening 9 providedin the base of the core element and the pipe it associated therewith as a valve (not shown) associated with this pipe will be kept closed until the level of the stufi in the stuff chamber reaches a predetermined height above the top of the wire gauze covering.

In starting up the apparatus some of the separated water will flow into the inner member t which will thereafter remain filled with water and thus in effect function as a solid body.

The purpose of this inner member 4 is to reduce the effective volume of the interior of the core member and thus ensure the raising of the level of the pulp in the pulp chamber at a greater rate than would be possible if the inner member Were not provided, which in turn operates to prevent an undue thickening of the deposited layer at a position adjacent to the lower end of the core member.

When the liquid has risen to the predetermined height, the valve associated with the pipe i!) will be opened and water will be sucked away, the pipe being connected to some source of suction, the stuff being continuously supplied until the layer of fibrous material deposited on the foraminous core element has reached the desired thickness, after which the supply of the fluent fibrous pulp will be interrupted and the Water in the foraminous core element will continue to be sucked away through the pipe in and an outlet valve on the pipe ii will be opened to permit the escape of the excess stuff from the stuff chamber. After this air is sucked through the deposited layer of felted fibre by the connection of the pipe it! with a vacuum pump.

The outer mould element is then brought into position over the core element.

This outer mould element comprises essentially an outer casing i2 furnished at its lower end with a surface 43 adapted to co-operate with a seating It provided on the base 5 supporting the foraminous core element and at its upper end with a disc i5 furnished with a tubular stem iii slidable in a guide I! provided in the cover I8 of the casing to which is secured means for raising and lowering the outer mould element.

Within the outer casing there is located a sleeve formed of two layers of rubber is, [to secured at its upper end to the disc 55 above referred to by means of a clamping ring i511, the disc being covered with wire gauze i 5b, the lower end of the sleeve being clamped to a ring 25 by retaining ring 28a and connected with the lower end of the outer casing 12 which is formed, as above stated, with a seating surface 53 adapted to make a fluid-tight joint at M with the base 5 to which the foramincus core element is secured.

The sleeve is furnished with a plurality of segmental slats 2| of steel or the like located between the two layers of rubber 19, Na extending from a point adjacent to its upper end to a point adjacent to its lower end to permit thedistension and contraction, of the sleeve but preventing its distortion and with each of these slats there is connected, at, a, position adjacent to its 6 upper end by a pin 38, a lever 22 secured on a pivot 23 provided in an annular chamber. 24 about the outer casing (see also Figures 2a and 2b), a similar arrangementbeing provided adjacent to the lower end of each of the slats.

The levers of the upper and lower sets thereof .are each connected to a ring 25 rotatable in guidesin one of the annular chambers, and with each of these rings there is associated rams 26 operating in cylinders 21 connected with a res: ervoir 21a (Figure 3), a valve being provided in the connection 28, see Figure 3, between each cylinder and the reservoir for establishing and interrupting communication between the cylinders and reservoir.

Means is provided at lfia for introducing air under pressure into the space between the sleeve and the outer casing of the outer mould element in order that the sleeve may be forced against the deposited mass of felted fibrous material in order to consolidate it.

On the introduction of air under pressure by way of the pipe 16a into the space between the sleeve l9 and the outer case E2 of the outer mould element the sleeve contracts initially by an amount equal to the lost motion provided by the holes 29 in the levers 22 .in which the pins 30 are engaged and upon further contraction which is promoted by the action of air under pressure the sleeve by means of its connections with the levers, causes rotation of the ring 25 in a clockwise direction thereby causing a, linear motion of the rams 26 inthe cylinders 27..

The valve between the cylinders and the reservoir is at this time open so that the cylinders fill with water;

The layer of fibre deposited on the inner case element is thus consolidated and when astate of equilibrium is reached, this valve is closed. The space between the ram and the closed end of the cylinder remains fiiled with water. The airpressure between the rubber sleeveand the outer casing is released. This causes no motion of the sleeve ,or parts connected with it, as the sleeve is so dimensioned that it will fit tightly or under some tension over the body of felted material formed on the foraminous core element.

Air pressure is now introduced in the foraminous core element by way of the pipe 3|, causing a distension of the web and the sleeve with it, equivalent to the lost motion or slack in the sleeve bracket provided by the holes 29 in which the pins 30 are engaged with the levers 22 Any further distension of the bag isnow resisted by the reaction of the water in the cylinders, i. e. a pressure is created within the cy1inder to resist further movement of the levers and sleeve. However, by this time the web (or felted fibrous layer) is freed from the foraminous core element. Coincident with the taking up of this lost motion a vacuum or a condition of reduced pressure is normally produced within the space between the sleeve and the outer casing by connection of the pipe led with a pump.

This serves to keep the sleeve and also the web sufficiently distended and simultaneously a sub-atmospheric pressure is admitted to hollow spindle i5 and so through the gauze face of disc i5 to the outer side of the formed hollow body so enabling the web to be lifted away from the foraminous core element.v

The outer mould element is then raised and for raising it, as above indicated, it may be associated with a crane adapted, not only to lower it but to swing the outer mould element into the body may be deposited on means for eiiecting its further treatment as, for instance, on a drying frame, the hookof the crane being engaged with a shackle on the end of the rod 32. f

' When the outer mould element is this position the connection between the reservoir and the rams controlling the motion of the levers is opened and the pressure between the, walls of the sleeve and the outer casing of the outer mould element is, if necessary, further reduced by connection of the pipe 56a with a vacuum pump or the like.

The sleeve is thus distended or expanded and at this time or subsequently air under pressure is introduced past the disc 55 by way of the pipe i6 and through the gauze and thus about the end and walls of the formed body, these two operations resulting in the detachment of the moulded body of material from the outer mould element, after which the outer mould element while still distended may be returned into the position in which it is suspended above and subsequently lowered over the foraminous core element.

In order that when it is lowered it may be locked in position over the core element durin the pressing operation by the sleeve in consolidating the felted fibrous material, a system of links 33 may be arranged with the shackle by which the outer mould element is secured to the crane, the links being associated with a spring or springs 34 adapted to cause them to force outward means 35 adapted. to engage in recesses 36 provided on the upper portion of the stufi chamber.

To wash away any fibrous material adhering to the foraminous core element after the removal of one formed hollow, body and prior to the reintroduction of the foraminous pulp into the stuff chamber, water is admitted by way of the pipe 31 connected to the distributor 38, the water so admitted operating to flush the forarninous member.

As will be understood a seamless hollow body formed of a plurality of independently consolidated layers of fibrous pulp may be produced by the apparatus described, in which case the overform or outer mould element will be brought into position with respect to the foraminous core element at appropriate times in order to consolidate the individually deposited layers, the deposition of such layers being secured'by the introduction of a further body of fluent pulp after the layer previously deposited on the core element has been consolidated on removal therefrom in the manner generally above described.

Where, as may be desirable, material additional to that forming the fluent fibrous pulp is introduced into the stud chamber for the purpose, for instance, of reducing the porosity of the formed body of felted fibrous material or renexpansible and contractable non-foraminous mould element, a casing surroundin said nonforaminous mould element, means supporting the mould element and said casing in spaced relation tothe core element, means for introducing air under pressure into the casing for contracting the mould element to compress-said body of fibrous material on the core element, meansfor expanding the non-foraminous mould element on sufiicient for the body of fibrous material to be a detached from the foraminous core element and to'be retained within the mould element, means for raising the mould element, and means forreleasing the limiting means to accommodate, further expansion of the non-foraminous mould element to facilitate release of the fibrous body.

2. Apparatus for forming seamless hollow bodies by aspiration of a liquid suspension of fibrous pulp comprising, a yet, a foraminous core element in said vat, means for introducing a liquid suspension of fibrous pulp between the innersurface of the vat and the outer surface of the core element, means for withdrawing liquid which separates from the pulp and passes through the ioraminous core element leaving a body of fibrous material thereon, an expansible and contractable non -foraminous mould element, a casing surrounding said'm'ould element and secured to the lower extremity thereof, a seating surface on the lower end of said casing, a seating surface carried by said vat for engagement by the first dering it waterproof, these materials may be introduced with the fluent pulp or subsequently.

I claim: V

1. Apparatus for forming seamless hollow bodies by aspiration of a liquid suspension of fibrous pulp comprising, a vat, a foraminous core element in said vat, means for introducing a liquid suspension of fibrous pulp between themner surface of the vat and the outer surface of the foraminous core element, means for Withdrawing liquid which separates from the pulp through the foramin'ous core element leavinga body of fibrous material deposited thereon, an

seatin surface and suppcrtingthe mould element and said casing in spaced relation to said core element,.means for introducing air under pressure into said casing contracting the mould element to compress the fibrous material on the core element, means for introducing air under pressure into the foraminous core element to expand and facilitate detachment of the fibrous material therefrom, means limiting the expansion of the mould element, means for raising the mould element, and means for releasing the limiting means to accommodate further expansion of the mould element, a

3. Apparatus for forming hollow bodies by aspiration of a liquid suspension of fibrous pulp comprising, a vat, a foraminous core element in said vat, means for introducing a liquid suspension of fibrous pulp between the inner surface of the vat and the outer surface of the foraminous core element, means for withdrawing iiquid which separates from the pulp and passes through the foraminous core element leaving a body of fibrous material thereon, an expansible and contractable non-foraminous mould element, formed mainly of rubber having spaced relatively. rigid slots therein grouped to provide segmental elements, levers connected to the segmental elements, "a casing surrounding said non-foraminous mould element, pivotal connections on said'casing for said levers, a ring around said casingja connec element, means for expandingrthe non-forame inous mould element, said interrupting means limiting expansion of said mould element to an extent sufiicient to enable the fibrous body to be detached from said core element, means for raising the mould element, and said interrupting means being operable to enable further expansion of the mould element to facilitate release of the fibrous body.

4. Apparatus for forming hollow bodies by aspiration of a liquid suspension of fibrous pulp comprising, a vat, a foraminous core element in said vat, means for introducing a liquid suspension of pulp fibers between the inner surface of the vat and the outer surface of the core element, means for withdrawing liquid which passes through the foraminous core element leaving a body of fibrous material thereon, an expansible and contractable, non-foraminous mould element, levers connected to said mould element at circumferentially spaced points, a casing surrounding said mould element, pivotal connections on said casing for said levers, a ring around said casing, a hydraulic ram connected to said ring, a cylinder for said ram, a liquid reservoir, a tubular connection between the cylinder and said reservoir, means for interrupting said tubular connection, means for contracting the mould element to compress the fibrous body on the core element, means for expanding the mould element, said interrupting means limiting expansion of said mould element, means for raising the mould element, and the opening of said interrupting means enabling further expansion of the mould element to facilitate the release of the fibrous body.

5. Apparatus for forming hollow bodies by aspiration of a liquid suspension of fibrous pulp comprising, a vat, a foraminous core element in said vat, means for introducing a liquid suspension of fibrous pulp between the inner surface of the vat and the outer surface of the foraminous core element, means for withdrawing the liquid which passes through the foraminous core element leaving a body of fibrous material deposited thereon, an expansible and contractable non-foraminous mould element and having spaced segmental elements of relatively rigid material, levers connected to the segmental elements, a casing surrounding said non-foraminous mould element and secured to its lower end thereof, a seating surface on the lower end of the casing, a seating surface carried by the vat engaging with the seating surface on the casing, pivotal connections on the casing for the levers, rings extending about the chamber adjacent to its upper and lower end, a connection between each of the levers and the adjacent ring, a hydraulic ram secured to each of the rings, cylinders in which such rams operate, a liquid reservoir, tubular connections between the cylinders and said reservoir into and from which liquid will be displaced as the result of movement of the levers and rings in consequence of the expansion and contraction of the mould element, means for interrupting the connection between the cylinders and the reservoir to maintain the levers in the position into which they mould element, means for raising the mould element, and the opening of said interrupting means enabling further expansion of the non-foraminous mould element to facilitate the release of the body of fibrous material.

MAURICE GEORGE ROBERT NEWBOULD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 293,220 Bodge Feb. 12, 1884 1,637,532 Oliver et a1. Aug. 2, 1927 2,337,574

Sloan et al. Dec. 28, 1943