US 3914079 A
A succession of rectangular mats, consisting essentially of asbestos fibers or other filamentary material held together by a wet hydraulic binder such as cement, are conveyed between two endless belts through the gap between a pair of horizontal platens of a press. At least the lower belt and platen are perforated to enable the application of suction to the underside of the mats whereby the same are held in fixed position on the lower belt at least on approaching the press and during compaction between the platens. The upper belt and platen may also have openings for facilitating the separation of the resulting board from the upper belt, upon the reopening of the press, by a blast of air under pressure.
Claims available in
Description (OCR text may contain errors)
United States Patent  3,914,079 Kober Oct. 21, 1975  APPARATUS FOR PRODUCING BOARDS OF 3,353,236 11/1967 Stedman 425/DIG. 201 FILAMENTARY MATERIAL 3,737,276 6/1973 Hill et a1. 425/406 X 3,801,243 4/1974 Smith et al 425/80 Inventor: Harald Kober, Wanne-Eickel,
Germany Primary Examiner-Robert L. Spicer, Jr.  Assignee: G. Siempelkamp & C0., Krefeld, n y, g Firm-Karl ROSS; Herbert Germany Dubno  Filed: July 23, 1973 57 ABSTRACT  Appl. No.: 381,435 1 A succession of rectangular mats, consisting essentially of asbestos fibers or other filamentary material  Forelgn Apphcatlon Pnomy Data held together by a wet hydraulic binder such as ce- July 29, 1972 Germany 2237362 ment, are conveyed between two endless belts through the gap between a pair of horizontal platens of a press. I 425/ At least the lower belt and platen are perforated to en- 425/437; 425/DIG. 200 able the application of suction to the underside of the  Int. Cl. B29C 3/04 mats whereby the same are held in fixed position on  Field of Search 264/109; 425/80, 81, 8,6, the lower belt at least on approaching the press and 425/371, 225, 324 R, 406, 96, 411, DIG. during compaction between the platens. The upper 200, DIG. 201, 75, 437; /151 belt and platen may also have openings for facilitating the separation of the resulting board from the upper  References Cited belt, upon the reopening of the press, by a blast of air UNITED STATES PATENTS under Pressure- 2,457,784 12/1948 Slayter 425/80 X l 6 Claims 3 Drawing Figures 3,226,764 l/l966 l-Ioslettler 425/80 T0 HAT PRESS 021v: PRocmnm-R SUPPLIEE 1 l t 20 I I9 351.1- DRIVE US. Patent Oct.21, 1975 Sheet10f2 3,914,079
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US. Patent Oct. 21, 1975 Sheet 2 of2 3,914,079
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2 /6 W COMPRESSED corzgessw All? APPARATUS FOR PRODUCING BOARDS OF FILAMENTARY MATERIAL FIELD OF THE INVENTION My present invention relates to a method of and an apparatus for producing boards of filamentary material, e.g., asbestos fibers, held together by a hydraulic binder such as cement applied in a wet state to a mat of such fibers.
BACKGROUND OF THE INVENTION Boards of this description can be serially produced by forming a continuous web, consisting of the fibrous material impregnated by the wet binder, on the periphery of a rotating drum and cutting this web into usually rectangular sections consituting the mats that are to be compacted in a press with relatively reciprocable lower and upper platens. Conventional transporting mechanisms, designed to convey these mats to the press, cannot handle them as fast as they come from the supply drum; this is true because the wet mats slide easily on a fast-moving conveyor and thus do not invariably remain thereon in a position designed to align them with the press platens just prior to their closure. It has therefore been the practice heretofore to assemble a number of such mats, with interposition of separating layers, in a stack for joint compaction in the press. The stacking and subsequent unstacking of these mats requires additional equipment and/or manual work; also, since the several mats of a stack at the instant of pressing have been in existence for different lengths of time and have therefore reached different degrees of preliminary setting of their binder, production is not uniform.
' OBJECTS OF THE INVENTION The general object of my present invention is to provide a method of producing such boards without the need for initial stacking, i.e., with individual pressing of each mat as soon as it arrives from the supply station.
A related object is to provide an apparatus for making such boards by simple means and in a continuous operation.
SUMMARY OF THE INVENTION In accordance with my present invention, the oncoming mats are consecutively moved on a perforated conveyor through a pressing station for compaction with expulsion of excess water therefrom; the mats are held in position on the conveyor, on their way to the press as well as within same, by suction continuously applied to their undersides through the conveyor.
To facilitate the maintenance of the applied suction inside the press, the lower press platen has perforations communicating with suction means such as the intake side ofa pump, the same or similar suction means communicating with perforations of a support surface disposed substantially at the level of the lower platen on the entrance side of the press. If desired, such a perforated support surface subjected to suction may also be provided again substantially at the level of the lower platen on the exit side of the press, both perforated surfaces being overlain by the upper run of the conveyor which passes between the perforated lower press platen and the confronting upper press platen. If desired, either or both of these platens may be heated to accelerate the hardening of the binder; in any event, the water squeezed out from the mat during the compaction step is drained off through the perforations of the lower platen which thus have a dual function.
According to another advantageous feature of my invention, the mat-carrying perforated conveyor is synchronized with an endless band which passes, in its entirety or at least with its lower run, between the two platens above that conveyor so that each mat is sandwiched between the conveyor and the band on traveling through the gap between the platens. The band may also be perforated in order to be traversed by a blast of air or other fluid under pressure, exiting from one or more passages in the upper platen upon the reopening of the press, which serves to separate the compacted mat from the upper platen and from the band upon its discharge from the press. The continued application of suction to the underside of the mat as it exits from the press, via a second perforated support surface as mentioned above, further aids in this separation.
If the upper platen is vertically reciprocable, the band overlying the conveyor should be somewhat yieldable or guided with enough slack to allow for such reciprocation. The lower platen is preferably stationary so as not to subject the matsto sudden level changes. If the press frame carrying these platens is fixedly positioned, the motion of the conveyor and of the overlying band may be temporarily halted at the instant of press closure; it is also possible, e.g., as disclosed in commonly owned US. Pat. No. 3,607,561, to mount this press frame on a horizontally movable carriage and to let it travel with the upper conveyor run during the time of closure, the press returning to its starting position immediately thereafter in preparation for the compaction of the next mat.
BRIEF DESCRIPTION OF THE DRAWING The above and other features of my invention will now be described in detail with reference to the accompanying drawing in which:
FIG. 1 is a side-elevational view, partly in section, of a pressing station forming part of an apparatus for producing filamentary boards in accordance with this invention:
FIG. 2 is a view similar to that of FIG. 1, but drawn to a larger scale, of the entrance side of the pressing station; and
FIG. 3 is a cross-sectional view taken on the line III- III of FIG. 1.
SPECIFIC DESCRIPTION The apparatus shown in the drawing comprises a conventional one-stage press with a frame 1, a vertically reciprocable beam 2 carrying an upper platen 4, and a stationary beam 3 supporting a lower platen 5. The beam 2 is coupled to a conventional driving mechanism 18 controlled by a programmer 20 in the rhythm of a nonillustrated supply station, such as the aforedescribed drum, delivering a succession of mats l2 essentially composed of asbestos fibers and cement. The mats are deposited on an endless conveyor belt 8 in the form of a wire mesh, this belt being led around two rollers 23, 24 with its upper run passing through the gap between platens 4 and 5. Roller 23 is shown coupled to a driving mechanism 19 which is also controlled by the programmer 20. If necessary, the belt 8 may be composed of a plurality of sections articulated to one another, the movement of the belt being so co-ordinated with the operating speed of the supply station that the mats l2 deposited on the belt do not come to rest on the junctions between these segments.
Platen 5 is provided with a system of internal channels 6 opening at a multiplicity of locations at its top side overlain by the upper run of the perforated belt 8. These channels communicate, through a conduit 6, with a vacuum chamber in a hollow support 10 whose perforated upper surface is level with that of platen 5; support 10 is rigid with beam 3 and underlies the upper run of belt 8 upstream of thepress, i.e., on the side where the oncoming wet mats 12 enter the gap between platens 4 and 5. A similar hollow support 17 on the downstream side, also rigid with beam 3, underlies the upper belt run and forms a vacuum chamber communicating via a pipe 6" with the channels 6 of platen 5. The two vacuum chambers and the channels 6 are maintained under low pressure by being connected to the intake side of a suction pump 21 .via a conduit 22.
An endless band 9, whose construction may be similar to that of belt 8, passes with its two runs through the press gap immediately below the upper platen 4. The latter, as shown in FIG. 3, is provided with internal passages 16 to which a blast of compressed air is delivered, under the control of programmer 20, upon every rise of beam 2 and platen 4 after the compaction of a mat 12 between the two platens. The air blast passes through the perforations of band 9 and helps detach the compressed mat from that band and from the upper platen.
The continuous operation of suction pump 21 insures that each mat 12 remains in an invariable position relative to the upper run of belt 8, from the point of its delivery to the belt by the supply station to the point of its dischargefrom that belt on the exit side of the press.
To control the moisture content of each mat, especially on its top side subjected to more rapid evaporation, a sprinkler 14 continuously irrigates the band 9 on the entrance side of the press where this band is led around rollers 13, one of them being shown driven by mechanism 19 in synchronism with the band 8. At the exit side, where the band 9 passes around guide rollers 23, a continuously rotating scrubbing brush 15 cleans that band from adhering debris which are swept into an exhaust 24.
It will be apparent that the single suction pump 21 may be replaced by a plurality of such pumps respectively connected to channels 6, vacuum chamber 10' and the corresponding chamber of support 17; the latter support could also be omitted in some instances.
The apparatus shown in the drawing can be operated at a conveyor speed which normally, in the absence of suction means 21 and perforated support 10, would cause the mats 12 to slide onthe band 8 before reaching the press platen 4.
If the apertures of the perforated conveyor 8 are large, a fine-mesh wire screen or the like may be interposed between each mat and the conveyor, either as a continuous element or divided into individual sections,
as shown in commonly owned application Ser. No. 381,436 filed by me jointly with E. J. C. Huydts on even date herewith.
Compressed asbestos-cement boards produced with this apparatus can be used as substrates for making laminated plates of the type described in my copending application Ser. No. 143,569 filed May 14, 1971, now,
patent No. 3,753,827.
I claim: 1. An apparatus for producing boards of filamentary material, comprising:
a press including a perforated lower platen and an upper platen spacedly overlying said lower platen,
said platens being vertically reciprocable relatively to each other;
a perforated endless conveyor having an upper run.
passing between said platens; support means for said conveyor provided with a perforated surface substantially level with said lower platen at least on an entrance side of the press underneath said upper run; and
suction means communicating with the perforations.
of said surface and of said lower platen for holding in position a filamentary mat, permeated by a wet.
hydraulic binder, deposited uponsaid conveyor outside the press for compaction between said platens.
2. An apparatus as defined in claim 1 further comprising an endless band having at least a lower run pass ing between said platens above said conveyor, said band and said conveyor being coupled to each other for synchronous motion with said mat sandwiched therebe- 4. An apparatus as defined in claim 2,.further comprising irrigation means trained upon said band on said entrance side for controlling the moisture of the mat before compaction.
5. An apparatus as. defined in claim 2, further comprising cleaning means for the mat-contacting surface of said band atan exit side of the press.
6. An apparatus as defined in claim 1 wherein said support means has another perforated surface, commu-,
nicating withsaid suction means, disposed underneath said upper run substantially at the level of said lower platen on an exit side of the press. l =l