Abstract: A method and apparatus for producing SO.sub.2 -containing gas and cement clinker by splitting waste gypsum and anhydrite, using paper fibers as the reducing agent, and firing the splitting residue with additives. The cement forming additives are formed into a mixture with the anhydrite and the mixture is compacted before the final drying and calcining, whereupon the anhydrite containing mixture is subjected to the splitting reaction and firing to form the clinker.

Abstract: A method and apparatus for producing SO.sub.2 -containing gas and cement clinker by splitting waste gypsum and anhydrite, using paper fibers as the reducing agent, and firing the splitting residue with additives. The cement forming additives are formed into a mixture with the anhydrite and the mixture is compacted before the final drying and calcining, whereupon the anhydrite containing mixture is subjected to the splitting reaction and firing to form the clinker.

Abstract: A rotary kiln has a generally cylindrical housing centered on and extending along an axis inclined to the horizontal and having an upper upstream end and a lower downstream end and a drive that rotates the kiln about its axis. Particles to be heat-treated are fed into the housing at the upstream end and are extracted from the downstream end. A plurality of axially separate heat-exchange radiators fixed in the housing are connected axially in series and a fluent heat-exchange medium is flowed serially through the radiators from the downstream end of the housing to the upstream end of the housing.

Abstract: Production of plasterboard includes spreading of a mixture formed of gyps fibers and water onto a continuously moving belt to form a spread layer subsequently precompressed to 110% to 180% of a final board thickness and successively wetted from both sides and thereafter compressing the wetted layer to the final board thickness.

Abstract: Process and apparatus for the continuous production of gypsum fiber plates in which the fiber component is dewatered and rediluted with water recovered from the gypsum-fiber suspension after it has been spread on a belt, passed over at least two suction boxes and densified on the last suction box by a densifying device engaging the filter cake layer from the top.

Abstract: A process and apparatus for the continuous production of a uniform layer of oose material on a forming belt has a receiving belt onto which the loose product is deposited by a gravity chute in strips transverse to a travel direction of the receiving belt. A smoothing device above the receiving belt engages the strip layer over the entire length thereof on the receiving belt and smooths the material before it passes to a dispersing device directly or via said dispersion belt.

Abstract: The invention is directed to an apparatus for the production of plate-sha bodies from a mixture of plaster and fibrous materials. The apparatus has a conveying means, spreading means, a first and second press, an afterwetting station and a setting and drying station. The afterwetting station is located between the first press and the second press and has separate means for wetting the upper side and the underside of a raw board being processed. The separate wetting means can be independently controlled.

Abstract: A module for the construction of a cleaning room ceiling has a housing wh can be fitted like a tile in the ceiling and which is divided internally into three chambers. A fan in an upper false floor draws air into the housing along an upper chamber which is aligned with a sound-damping lining. Sound-damping baffles are provided on the underside of the upper floor and the upper side and lower floor in the intermediate chamber and the bottom of the lower chamber is closed by high efficiency particle filters.

Abstract: A method of treating plasterboard production scrap wherein the pieces of the plasterboard scrap having the plaster attached to paper components, is passed through an apparatus which comprises a cylindrical housing in which radial arms carry ploughshares riding along the wall of the vessel and cutting heads are provided between the paths of the ploughshares. The apparatus so reduces the pieces that a homogeneous mixture of fibers of the paper components and granular gypsum is formed. This product mixed with raw gypsum provides a calcinable mixture which can be calcined for use in producing additional plasterboard.

Abstract: Plasterboard is made by first spreading a mixture of plaster, fibers and er and then pressing this moist mixture to form the raw board. The upper and lower surfaces of the raw board are then wetted and the thus wetted raw board is pressed with a pressure less than the original consolidation pressure.

Abstract: A mixer for mortar has part of its water feed introduced between a rotating isk and the floor of the disk housing, this water being propelled outward through an annular constriction in the clearance between the disk and the housing so that the rotor is kept constantly pressured by the inflowing water. The rest of the water is introduced through inlets spaced in a ringlike arrangement in the housing cover so as to produce a continuous water film on the rotating disk, onto which the powdered plaster and any other additives are fed.

Abstract: In the process for making gypsum fiberboard the boards are formed or molded rom a mash containing calcium sulfate dihydrate and fiberous material. By heating and subsequently cooling the boards the dihydrate is first converted into the hemihydrate and subsequently recrystallized again to the dihydrate. Known processes require day line setting times which are economically disadvantageous. According to the present invention these times are shortened by pulling or drawing water, an aqueous solution or a water containing mixture through the boards after the cooling step. Advantageously a setting accelerating agent can be dissolved in the water. By these features the setting time can be shortened to less than two hours. By addition of a binding agent, e.g. starch, to the fluid drawn through the boards the strength of the boards is increased.

Abstract: A cylindrical cutter head comprises a cutter head body having a cylindrical surface which is centered on an axis and which is formed with a plurality of radially outwardly open main grooves extending parallel to the axis and each having relative to a normal direction of rotation of the body about the axis a leading flank and a trailing flank. These flanks are generally planar and converge radially outward. A disposable knife blade in each of the grooves is pressed against the trailing flank thereof by an outwardly tapered centrifugal wedge braced radially between the blade and the leading flank. Each groove is formed immediately forward of its trailing flank with a radially inwardly projecting groove extension. Thus wide regrindable blades can be fitted in the groove with their rear edges seated in the respective groove extensions.

Abstract: A cylindrical cutter head for a wood planing machine has mounted in its cumference a number of disposable knife blades which are clamped in place with the help of centrifugal wedges in lengthwise grooves. Between each disposable knife blade and each centrifugal wedge there is positioned a bracket of L-shaped profile consisting of a base strip which is immovably attached to the cutter head body and a clamping strip bearing against the knife blade, this clamping strip being elastically deformable to a small extent. By means of a conformal relation of a profiled region of the disposable knife blade with a corresponding profiled region of the clamping strip, the disposable knife blade is held firmly in position when clamped in. After loosening of the centrifugal wedge, the disposable knife blade can be easily withdrawn in a lengthwise direction and can be replaced with accurate positioning.

Abstract: The invention relates to a continuous dryer for veneer. In addition to terature sensors near the inlet and middle zones to determine heat demand and to control heat input in these zones, the dryer also has an infrared detector at the exit end to determine surface temperature and thus to determine residual moisture of the veneer. The signal from this infrared detector is processed to give a control signal for blowers in the drying zones near the exit. By this means, more precise and reliable control in final moisture is achieved. Variations in dryer load, initial moisture, wood density, and sheet thickness can be better tolerated.

Abstract: The sailing and floating of the sheets which has occurred uncontrollably at certain speeds is avoided so that an exact stacking is permitted at high speeds. The vacuum conveyor is a vacuum belt conveyor whose vacuum box with circulating vacuum belts extends over the entire stacking location and the brake device. The brake device comprises an upper circulating belt supported by a vacuum chamber whose upper strand reaches up to the stacking location. Thus the sheets during the stacking process are guided precisely and do not float freely.

Abstract: A drying apparatus for sheets of sliced veneer has two conveyor belts lying one above the other running together jointly around a partially curvilinear, looped path guided by a plurality of guide apparatuses, the belts being positioned so that the sheets may be inserted between the belts for transport in a direction transverse to their widths, wherein the conveyor belts run rectilinearly between at least two of the adjacent guide apparatuses for a distance at least equal to half the maximum width of the sheets fed between the belts. The guide apparatuses may be rotatable cylindrical structures, for example rollers or cylinders, whose axes of rotation preferably all lie in the same horizontal plane. These rotatable cylindrical structures may be provided with brakes, drying and heating units as well. Furthermore the drying apparatus provides a velocity difference between the belts of from 2% to 5% and the belts passing between adjacent pairs of rollers are inclined at angles from 30.degree. to 75.degree..

Abstract: A method of and apparatus for producing gypsum fiber boards includes introducing shaped boards provided of a mash of calcium sulphate dihydrate and fibrous material and possibly additives after dewatering and shaping the mash into at least one pressure vessel and to heat the boards at saturated steam atmosphere to 120.degree.-160.degree. C. over a predetermined period. Thereafter, the boards are allowed to cool down within the pressure vessel to a temperature of about 100.degree. or less before being discharged therefrom.

Abstract: A drying apparatus for sheets of sliced veneer has two conveyor belts lying one above the other running together jointly around a partially curvilinear, looped path guided by a plurality of guide apparatuses, the belts being positioned so that the sheets may be inserted between the belts for transport in a direction transverse to their widths, wherein the conveyor belts run rectilinearly between at least two of the adjacent guide apparatuses for a distance at least equal to half the maximum width of the sheets fed between the belts. The guide apparatuses may be rotatable cylindrical structures, for example rollers or cylinders, whose axes of rotation preferably all lie in the same horizontal plane. These rotatable cylindrical structures may be provided with brakes, drying and heating units as well. Furthermore the drying apparatus provides a velocity difference between the belts of from 2% to 5% and the belts passing between adjacent pairs of rollers are inclined at angles from 30.degree. to 75.degree..

Abstract: A continuous drier for plywood sheets is provided at its inlet end with a nsing device measuring the width and the spacing of the plywood sheets entering the drier. The values measured by the sensing device are transmitted to a control device, which by means of a calculator regulates the speed of a conveyor transporting the plywood sheets through consecutive sections of the drier in such a manner that the plywood sheets follow each other closely on the conveyor without overlapping. Each of the sections is provided with a heater and a ventilator which blows air over the heater, and the hot air is directed by installations onto the plywood sheets. In order to compensate the effect of the varying speed of the conveyor with respect to the drying of the plywood sheets, the control device preferably controls also the volume of the streams of hot air by varying the speed of the ventilators. This will result in a considerable saving of the driving energy.