Derrick Corporation

Alex DeMay

Kurt Stodolka

Keith F Wojciechowski

James R Colgrove

Anthony J Lipa

A screen assembly is formed by attaching side edges of a plurality of screen elements to each other. Reinforcing fibers may be embedded in the material of selected screen elements. The reinforcing fibers extend in a direction in which the screen assembly will be tensioned to secure the screen assembly to a screening machine. Hook strips may be attached to ends or sides of the screen assembly to facilitate mounting the screen assembly to a screening machine.

Injection molded screening apparatuses and methods

A disclosed screening apparatus includes a subgrid, and a screen element attached to the subgrid via laser welding at a plurality of attachment positions such that, under vibrational excitation, the screen element has a pre-determined profile of vibrational motion relative to the subgrid. The screen element may be attached at a maximal number of attachment locations to the subgrid to minimize relative motion of the screen element and the subgrid under vibrational excitation, or the screen element may be attached a sub-set of the maximal number of attachment locations to allow vibrational motion of the screen element relative to the subgrid. A disclosed method may include attaching a plurality of screen elements to a respective plurality of subgrids, attaching the plurality of subgrids to one another to form a screening pre-assembly, and cutting edges of the screening pre-assembly to form the screen assembly having a perimeter with a pre-determined shape.

Thermoplastic polyurethane (TPU) compositions, methods for producing TPU compositions, methods of using TPU compositions, and apparatuses produced therefrom are disclosed. Disclosed TPU compositions include a thermoplastic polyurethane polymer, a heat stabilizer, a flow agent, and a filler material. The filler may be a glass fiber. Disclosed TPU compositions have improved thermal stability and improved flow properties suitable for injection molding of articles of manufacture having a large plurality of fine openings or pores. Articles produced from the composition have superior thermal stability, abrasion resistance, and chemical resistance. Example articles include screening members for vibratory screening machines. Further embodiments include compositions without heat stabilizers, flow agents, and filler materials, and compositions in which two TPU materials having different harnesses are combined to generate a material with a pre-determined hardness. Injection molded screen elements having openings from 25 to 150 microns and open screening area from 10% to 35% are disclosed.

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Buffalo, NY, United States of America

Alex DeMay