US2644373A

US2644373A - Apparatus for the continuous production of cement-fiber sheets

Info

Publication number: US2644373A
Application number: US765092A
Authority: US
Inventors: Salvaneschi Pino
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-10-31
Filing date: 1947-07-31
Publication date: 1953-07-07
Anticipated expiration: 1970-07-07

Description

3 1 7 t 3 w m h S I. t 2 w h s 2 July 7, 1953 P. SALVANESCHI APPARATUS FOR THE CONTINUOUS PRODUCTION OF CEMENT-FIBER SHEETS Filed July 31, 1947 lm'enfar 3 3w dam/yaw: iwqflyl? y 7, 1953 f P. SALVANESCHI 2,644,373

APPARATUS FOR THE CONTINUOUS PRODUCTIQN 0F CEMENT-FIBER SHEETS 2 Sheets-Sheet? Filed July 31, 1947 I r 5 ,w w m M M w A .5 f u A 6 0 N mm 3 I. o o P .m mm mm on n 3 E m 8 v mu mm on 4 h mm mm o N pm 0 H an A process is already known tio n of pipes and'other similar hollow bodies in which tubes are formed on a porous or permeable cylinder, inside' ofwhich a vacuum is'applied, through the action of one ormore vibratory feedtetbleSi-bonveniently operated around said cyl- Patented July 7, 1953 1 UNITED STATES PAT NT; OFFICE APPARATUS FOR THE CONTINUOUS PRO- DUCTION 0F CEMENT-FIBER SHEETS Pino Salvaneschi, Bron i, Italy 4 Application July-31, 1947, Serial No. 765,092 In Italy October 31, 1942 Section 1, Public Law 90, August s, 1946. i"

Patent expires October 31, 1962 '1 Claims.

-The present inventionrelates to a process and apparatus for producing sheets composed of mixtures offibers and cement. Y I

for the producinder.

-Intheabove mentioned known process, the production of the pipe through the formation of a layer "of'the desired thickness on the cylinder 1 after the latter has accomplished only one revolu- "tionis'obtained.'-' 1 1 Furthermore, this known process provides a v vibrocompacting action;exertedsimultaneously with the revolving 'motion and the application of vacuum in the inside ofcylinder. a w r -To produce cement sheets, for'example,-from mixtures offibers and cement or the like, it is expedient to form, by the above specified process, a ;pipe of suitable length and diameter, which is "theiicut along a generatrix, and finally unwound on a plane; {This system of cutting'and unwinding i'S- already known, and generally applied-in j'p'asteboa-rdmaking by well known machines.

However; itisobvious that the above mentioned known proce'ss only permits intermittent or discontinuous production. Moreover, the amount of additional processing off-'the sheet produced in such a-manner' depends,- at least to'a certain extent, uponits length, andconsequently upon the-cylinder diameter. 'It follows that,- after all,

-'should sheets of various length be produced,

either the-"cylinder has to be replaced to have a circumference substantially equal to the length ofthe desired sheet, or large lossesof material inthe' form' of 'scraps have to be suffered as the -length-of the formed sheet is trimmed to the desired dimension.

All of'the "above specified disadvantages'can be prevented by combining the known process with asystem which applies the vacuum in timed rela'tionship to the action of feeding and vibro- {compacting device's associated with. the rotated cylinder in accordance with the present inven- Accordingly, an object of the present inven- :tion is toprovide a process which allows continu- I -.-ous production of sheets-of constant width and indefin e, c st of s cce s vin Q constant. w dthr n a e te m n l t is al a oss bl i t Process e bqfiy i th i iqe.ta-gbtaiasheets=rtfaelreesirl1inis hed sides, by giying to the surface on 'which the sheets are formed a shape such as to sharply delimit the edges of said sheets, and/or to give to the sheets a predeterminedprofile.

Moreover, the devices-for the carryinginto effect of this invention are of simpler design,

being also more economically joperated'than' the already known types," and adapted to produce roughened, striped or longitudinally ribbed sheets, which are therefore particularly suitable' for'linings,coatings-or the like. I

It has been ascertained thatfshort fibres inay be advantageously; employed for obtaining-a product-with high waterproof properties and strength, by reason of the peculiar distribution of the fibers caused bythe action of the'vibrat- 'ng feeding hopper and of the vibro-compacting devices.

' In the accompanying drawings, illustrative embodiments of the invention are shown, by way of example, but it is to be understood that it is possible to carry into effect the'invention through other types of apparatus without departing from the'scope of'the invention. Inthe drawings:

"Fig. "'1 shows a diagrammatic cross-section of a machine for the continuous production of fsheetsn Fig, 2 shows an endless travelling band, fitted the machine of the-kind shownin Fig. 1, for

the continuousproduction of successive sheetsof predetermined length; Fig. 3 shows another machine for the continuous production of sheets having a predetermined length. r p

Fig. 4 shows a detail of the vibrating hopper of the device in Fig. 3.

Fig. 5 shows a detail of the vibrating compacting or compressing unit associated with the device'of Fig.3. 7

Fig. 6 shows a vacuum slide-valve, to be employed with the apparatus of Figs. 3 to 5, inclusive. L

" Referring first to Fig. 1,-wherein an apparatus embodying the present invention 'is illustrated,

reference numeral {I indicates a rotatable hollow drum or cylinder having a porous or permeable peripheral wall and mounted for rotation about a horizontal axis. The opposite ends of the'lc'ylinder l are preferably sealed by end'walls, and

a unit is provided in the interior of the'drum for exerting an inwardly-directed suction effect on successive portions of the porous periphery of, the. cylinder, as the latter is rotated. This suction exerting unit includes angularly related radialflwallsi andi l'h eld fixed position withtion 9. V sothat the-section 8 moves relative thereto as frontwall. I0. the lower; portion of the front wall I acts" to 3 in the cylinder and extending from the axis of rotation of the latter, substantially to the inside surface of the cylinders porous periphery. Sealing elements 3 and are carried by the outer edges of the walls 2 and 4, respectively, and engage slidably against the inner surface of the cylinders periphery. A conduit connects to the space defined between walls 2 and 4, adjacent the junction of the latter, and leads to an evacuating device (not shown) of conventional construction for exerting a suction or vacuum against the inside of the portion of the cylinders periphery located between the sealing elements 3 and 5. As the cylinder l rotates and the walls 2 and 4 are stationary, it is apparent that progressive sections of the cylinders periphery are successively subjected'to theisuction or vacuum in the space between walls 2 and 4.

As seen in Fig. 1, the walls 2 and 4 are anguv larly related by approximately 60, with the wall ,z'extending substantially vertically upward from the axis-of rotation and with the wall 4 being inclined in the direction of rotation of the cylinder as indicated by the arrow. Thus, as the cyltinder I .is rotated, the peripherythereof is exposed to Vacuum as it passes the uppermost position and continues tobe so exposed for approximately the following 6090f rotation. The interiorof cylinder I,'not included in the space between walls 12 ;and 4, is communicated with the atmosphere, so that, as the periphery of the cyl- =indermoves past sealing element 5, the pressures-inside and outside of the porous periphery are equalized and continue thus until the sealing element 3"is again reached. d q

A'fabric or porous felt'band. l2 extends: over v at least that portion of the periphery of cylinder l which is defined between the sealing elements 3 and 5 and moves with the cylinders periphery asthe latter is rotated. Upon leaving the periphery at a point after sealing element 5, the .band orweb I2 is supported by a suitable conveyor I1 for example, a roller conveyor of conventional construction. The band or Web [2 has a width slightly in excess of the width of the.

sheets to be formed thereon. I d

The mixture of fiber and cement, or other similar materials, from which the sheets are to be formed, is preferably in a pasty or damp con- ..dition, as distinguished from the wet mix or .10; which, at its lower portion, extends parallel to the'periphery of cylinder I and a" rear wall formed by an upper section 8 and a lower sec- The lower section 9 may be stationary,

the hopper is vibrated, or for "the sake of simplicity may be secured to section-,8 for movement with'the latter.- Side walls complete the hopper and may move with the front and back walls or be stationary. At least the front wall l0 and the rear wall section 8 are secured together andare mounted for vibrating motion in the direction of the two-headed arrow of Fig. 1 and about an axis H displaced forwardly of the Thus, as the hopper is vibrated,

compress or' compact the pasty ordampmixture distributed on the surface of web or band I 2. Since the underlying portion of the cylinders periphery and hence the porous web l2 are subjected to a vacuum during the distribution and initial compacting of the mixture, water and air are withdrawn from the mixture into the space between walls 2 and 4 and then evacuated from that interior space by the vacuum producing device associated therewith. Further, the'vacuum or suction acting on the under surface of'band l2 during distribution of the mixture on the latter serves to ensure the even distribution of the mixture over the entire surface of the band subjected to the vacuum.

Arranged in front of the hopper I, that is, spaced from the hopper in the direction of the rotation of cylinder 1, is a compacting or compressing device which includes a hammer or com- .pa'cting'f member I 3 mounted on an arm [4 pivotally mounted at l5 for vibratory movement in the direction of the two-headed arrow so'that the member l3 subjects the sheet [6 being produced to repeated and rapid compacting blows during the terminal portion of the travelof the band I 2 over the space defined between the seals 3 and 5. Thus, the remainder of the moisture and air occluded-within the mixture is driven out of the sheet I 6- and evacuated while the sheet is simultaneously compacted to increase the density and strength'thereof.

When the band [2 has-moved past the sealing element 5, and is no longer subjected to the vacuum effect, it is free to be. removed from the peripheral surface of cylinder. land to be guided by the roller conveyors I! with the plastic continuous sheetlfi thereon. In-the device of-Fig. l, the band or web -I2;is of substantially great length and is intendedto be wound. on and off two drums (not shown) located at opposite sides of the illustrated device as motion is imparted to the web or band by the rotated cylinder 1.

In the embodiment of the invention illustrated in Fig. 2, parts corresponding to thosedescribed in conncetion with the device of Fig. 1 arev indicated by the same reference numerals. The

embodiment of Fig. 2 is-intended to continuously producesuccessivesheets 0f predetermined length rather than the onecontinuous sheet of indeterminate length produced with the previously described device. In order to continuously produce such successive sheets, the web of band IZ-of the device-in Fig. 2 is provided with solid or impervious ribs l8 rigidly fixedon-the bandand extending transversely on the latter. The ribs are slightly shorter than the width of the band,iand slightly thinner than the sheet to be produced. The band 12 is a continuous element and passes over a loose or idler roller 19. 20 is a revolving brush with water sprayer, and diagrammatically represents a band washing device in place of which one of the already known beater types, having a'beating action integrated with the water sprayer, mightbeemployed. The walls 8- and- [0 of the hopper I, together with the vibrated compacting member l3,rbehave precisely as shaking tables, as in the embodiment of Fig. 1, and are suitably located and operated adjacent the cylinder surface. In the apparatus of Fig. 1 or 2 the mixture, which is-continuously poured into the hopper! by the pipe 6, is uniformly and regularly fed onth'e band owing to the'combined effectof the-gravity, of vibrations, of the suction and of the forward motion of the band whichis driven'by the -revolvin'gporous or 'permeablecylinder.

gof the band I2.

The numeral 2| is the A portion of the excess water, and the most of the air contained in the mixture, after filtering through the fabric band l2, fiow through the porous peripheral wall of the cylinder, then are sucked into the space defined by the walls 2, 4 and sealing elements 3, 5 and exhausted by the associated vacuum pump. The wall ll) of the vibrating hopper acts, as already said, as a shak- '.ing table, by feeding the mixture and causing a taneously with the relative motion of the sheet carried by the band, and with the suction effect exerted inside of the length of cylinder defined between the seals 3 and 5. a

, In each of Figs. 1 and 2, only asingle hopper is shown by way of example. In the practice,

' however, it maybe necessary to employ several hoppers, acting successively, in order to produce a sheet composed by a number of superposed layers, of the same or different fibrous or nonfibrous material. The same can be said for the vibratory compacting device, of which more than one may be employed, with the purpose of repeating the compacting of the sheet, as well as smoothing and finishing the-latter.

After the continuous sheet has been produced on the device'of Fig. 1, the, sheet is cut transversely as desired by means of one of the already known devices, such as automatic shears, a thin Carborundum wheel, or a suitably arranged bandsaw. The sheets so obtained can'be submitted to further processing. Another band can be secured to the trailing end of band l2 so as to obtain a continuous production. The band'l2,

conveniently wound-up on a drum, can be employed again after having been washed.

The variation shown in Fig. '2, permits the elimination of all hand washing and manipulations of the band, since the band in this embodiment is of the endless type. Moreover, this arrangement is adapted for the continuous production of sheets already cut to the desired l8 fixed on the band and made length. The ribs are slightly shorter of metal, rubber or leather,

than the width of the band, and slightly thinner than the sheet, and being impermeable eliminate the suction effect in the areas, of the band coveredby the ribs so thatthe mixture discharged -onto the ribs is drawn off the latter onto the adjacent exposed areas of the band, no mixture remaining on the ribs, and consequently sheets can'be obtained which are already'cut and finished on all four sides. The numeral I! in Fig.

4 2 is one of these finished sheets, and to takeoff .the same, it is sufficient to lay on it a plate; with a curvature equal to that which shall be taken .by the plastic sheet when, being no longer rel tained by the suction effect, it will only besubjected to the gravity action and will-fall clear The variation of Fig. 3, together with the corresponding details (Figs. 4, 5y'and 6), shows apparatus for carrying the invention into effect, by which the practical requirements can be better fulfilled when cylinders of large diameter are employed. g a

frame, on which the cyl- 6 inder 40, the axles 26 andil4, and the shafts130 and '38 are fitted. The cylinder 40 is supported thereof into an annular groove formed in a face of the member 52. The periphery Of cylinder 40 is in the form of a hollow annular channel of. substantially rectangular cross-section (Fig. 4) and having spaced radial partitions therein (Fig. 3) .to divide the interior of that channel .into a plurality of relatively sealed chambers: a,

11., each having a porous or foraminous outer wall. Each of the cylinder chambers is connected to a radial pipe communicating the respective chamber with the radially opening end of the related port or passage of valve member 52.

e An annular distributor member 45, fixedly mounted in relation to the frame 21, engages slidably in the groove formedin the face of valve member 52 (Fig. 6) and is:formed with a hollowed out section 4B extending circumferentially for approximately 90 and opening axially at the side of the distributor engaging in the valve member groove for communication with the axially opening ends of 'the successive valve ports as the latter come into registry with the hollowed out section 46. A conduit 41 connects. to the hollowed out section 46 and communicates the latter with a vacuum pump (not shown) or other similar device for establishing a vacuum or relatively low pressure in the hollowed-out section of distributor 45, and hence in those chambers of the cylinder'periphery corresponding to the valve ports registering with the section 46. As shown by the dotted lines in Fig; 3, the hollowed-out section 46 is disposed'tooccupy the upper left quadrant of the circular'path of the valve member 52, so that, with the cylinder in the position of Fig. 3, chambers Z, m, n and a are'subjected to the vacuum effect. As the cylinder 40 is rotated, in' the direction of the arrow of Fig. 3, the chambers successively occupying the positions of the chambers Z, m, nand a in that view'are subjected to the vacuum effect.

Seals

49 and 50 are carried by the distributor 45 and engage against valve member 52 to prevent leakage at the sliding surfaces of theseelements. As seen in Fig. 6, the distributor 45 is also formed. with an annular slot 48 extending therethat, as a chamber moves past the positionof chamber I in'Fig. 3, such chamber is vented to the atmosphere to equalize the pressures atuthe opposite sides of the porous outer wall thereof.

A webor band of porousmaterial may run over the cylinder '40, as in the previously, described embodiments,or the sheets may be formed,

directly on the surface of the cylinder which is provided with circumferentially spaced transverse ribs 379 of impervious material, so that, as in the apparatus of Fig. 2, successive sheetsof predetermined length are produced by. reason of the fact that the vacuum is only effective at opintermediate areas between successive ribs.

The pasty or damp mixture is conveyed to the location of the machine by a duct 6 which discharges into a hopper 22 similar to the previously described hopper l. Hopper 22 includes a front wall having a lower portion formed to com- .pact the mixture against the cylinder surface as the hopper is vibrated, a rear wall including an upper section 23 vibrating with the front wall ..and a lower section 24 which may be formedof resilient material, such as rubber, to permit the .ribs 39 to pass under the hopper to finish the side edges of the sheets during the final compacting of the latter.

In operation, the apparatus Of Fig. '3 performs substantially in the same manner as the devices described in connection with Figs. 1 and 2. When a section of the cylinder arrives under the hopper 22 and is subjected to the vacuum effect, the pasty mixture is discharged onto the cylinder in -the form of a sheet and is initially compacted by the vibrated front wall 25 of the hopper s0 that the removed water and air are drawn inwardly through the porous cylinder periphery into the underlying cylinder chamber for evacuation by the vacuum pump.

When, owing to the revolving motion of the cylinder, a sheet is brought out from under the compacting element 32 and the pressures at opposite sides of the cylinder wall are equalized, the

sheet is removed in the manner previously described, while on the opposite side of the cylindivide the cylinder in whatever number of chambers may be desired for producing any desired number of sheets at each revolution Of the cylinder.

Moreover, the apparatus shown in Fig. 3 can be provided with the endless band or web of Fig.

2, with or without the ribs 18, or with an elongated web combined with or without the roller table ll of Fig. l.

It should be noted that with the apparatus and process heretofore described, the thickness of the sheet can be varied from point to point of its cross-section by suitable shaping of the =hoppers, cylinder surfaces and compacting elements. Therefore, it is possible to produce longitudinally striped 0r ribbed sheets, since this exclusively depends from the profile of the hopper- -wall 25, andof the vibratory counter-mold or compacting elements 3| and 32.

As in the embodiments of Figs. 1 and 2, the apparatus Of Fig. 3 may include more than one hopper so that sheets may be produced; which are composed of successivelayers of the same or different mixtures.

Having now. particularlydescribed and ascertained the nature of my said invention and in what manner the same isto be performed, I declare that what I claim is:

1. A device for making cement-asbestos sheet material comprising a revolving drum rotating about a horizontal axis and having a permeable cylindrical wall, a permeable belt travelling eralwall. 55

a filtering web running over said peripheral wall aroundsaid drumfor an angle of less than 360,

means for creating a vacuum at the insideof part of the portion of said cylindrical wall covered by said'belt, a hopper for discharging a pasty cement-asbestos mixture downwardly onto the initial portion of said part of the beltand including a surface lying against said initialportion of said part of thebelt on said drum, a second surface lying on said belt in succession after said first mentioned surface, means for oscillating said first mentioned and said second mentioned surfaces in directions-angularly disposed -to said respective surfaces, and means for removing the material formed on said beltafter the belt has left the drum. I

2. Apparatus for the continuous production of cement-fiber sheets comprising arotatable'cylinder mounted for rotation about a horizontal axis and having a porous peripheral wall, a hopper disposed for discharging a pasty cementfiber mixture downwardly onto said wall of the cylinder and including a hopper Wall section extending along and adjacent to a portion of said peripheral wall of the cylinder, means for vibrating said hopper wall section in the direction radially of said cylinder, means for creating a vacuum at theinside Of said peripheral walland over a zone extending from the location of said hopper in the direction of rotation for less than 360, compacting" means disposed adjacent said peripheral wall at the terminal portion ofsaid vacuum zone and including a rockable member I mounted at its center for-swinging about an axis parallel to said axis of the cylinder, compacting 'elements at the opposite ends of said rockable tive tosaid rockable member in the direction ments may be equalized.

- 4. Apparatus according to claim 2; wherein said compacting elements are formed with pro- 'jections at the opposite ends thereof for finishing the side edges of the mixture on said periph- 5. Apparatus according to claim 2; including and in contact with the latter at least throughout said vacuum zone.

6. Apparatus for the continuous production of cement-fiber sheets comprising a cylinder rotatable about a horizontal axis and having a porous peripheral. wall, a hopper disposed for dischargthe vacuum at the areas of said peripheral wall disposed between successive impervious ribs, means for. compacting the mixture on said pe- '9' ripheral wall during passage through said vacuum zone, and means for removing the compacted mixture from said peripheral wall after passage out of said zone.

7. Apparatus according to claim 6; including an elongated filtering Web carrying said ribs and contacting said peripheral wall at least throughout said zone for receiving the discharged mixture.

PINO SALVANESCHI.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 775,511 Binns Nov. 22, 1904 I 1,347,724 Wagner July 27, 1920 1,547,613 Salisbury July 28,1925

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