Apparatus for the manufacture of tension screens

摘要

A screen assembly, the process for its manufacture, the apparatus used in the process and an adhesive presenting a system and the final product for accurately tensioned bonded screens. The screens include a screen frame and screen cloth bonded thereto by adhesive using bisphenol F epoxy resin, amine adduct hardener, a substantial percentage of amorphous silica and small amounts of glycerin and fumed or precipitated silicon dioxide. Titanium dioxide may also be employed for color. A screen assembly apparatus includes a screen cloth tensioning frame and a platform positionable adjacent a tensioned screen cloth. The platform includes heating elements about the periphery of a sheet heater on a lift table. The heating elements receive a screen frame which can be lifted into contact with a screen cloth in the tensioning frame. The sheet heater approaches the screen cloth itself. A thermal control cycle is presented which allows the screen frame to cool prior to the tensioned screen. Blowers enhance the cooling process of the screen frame. Resilient devices are provided to maintain tension in the screen cloth irrespective of heat expansion and to maintain a uniform pressure of the peripheral heating elements against the screen frame and in turn against the screen cloth.