Patent ID: 7810649
Filing Date: 2010-10-12
Classification: B07B

Abstract:
1. A frame over which woven wire mesh is to be stretched and secured to form a sieving screen which can be used to screen solids from drilling mud recovered from down-hole when drilling for oil or gas comprising a rectilinear moulded plastics frame having edge regions by which it is secured in place in a shaker and defining a plurality of rectilinear windows formed by an orthogonal array of intersecting ribs also of moulded plastics material at least some of which are internally reinforced by a structure comprising two spaced apart layers of orthogonal intersecting spaced apart wires, running parallel to the length and breadth of the rectilinear shape of the frame within the ribs to increase their rigidity, wherein: 1) the edge regions of the frame are reinforced internally by metal box-section members joined at their four corners and defining a perimeter reinforcement and 2) the ends of the wires are secured to the box-section member, and wherein the ends of the two layers of wires are secured to the upper and lower faces of the perimeter reinforcement.