Document Type and Number:
Japanese Patent JPH0370607
Kind Code:
B2
Abstract:
In the manufacture of cementitious board by depositing a slurry of hydraulic cementitious material, commonly gypsum plaster, between two facing sheets and forming it to the desired width and thickness prior to setting, the formation of voids in the core, due to air trapped in the slurry is avoided by vibrating the lower sheet (10) after the slurry (15) has been deposited on it, usually before the upper sheet (14) contacts the slurry, and subsequently vibrating the upper sheet when it comes into contact with the mass of cementitious slurry. The vibration of the lower sheet, for example by rotating polygonal shaft (20), causes bubbles of unwanted trapped air to rise through the slurry towards the upper surface and the accumulated bubbles are then broken by the vibration of the upper sheet, which may be accomplished by a second rotating shaft (21), before they become incorporated into the formed board as voids.
Inventors:
TOMASU ARUBAATO PIRUGURIMU
JON ROBAATO GURIIUZU
JON ROBAATO GURIIUZU
Application Number:
JP7487483A
Publication Date:
November 08, 1991
Filing Date:
April 27, 1983
Export Citation:
Assignee:
BPB INDUSTRIES PLC
International Classes:
B28B1/30; B28B1/087; B28B5/00; B28B19/00; B32B13/14
Next Patent: JPH0370608