Abstract: A blade including a body having a leading edge, a trailing edge, a surface point of maximum camber, and a low pressure surface extending between the leading edge and the trailing edge. The body further includes a high pressure surface extending between the leading edge and the trailing edge on an opposite side of the body relative to the low pressure surface. The low pressure surface includes a leading edge surface extending from the leading edge to the surface point of maximum camber. The blade further includes at least two ridges located on the leading edge surface, each ridge extending generally parallel to the leading edge.

Abstract: A pump seal is provided for use in a pump suited to move high viscosity and abrasive materials. A piston in the pump has a substantial amount of clearance relative to the cylinders in which it operates with the seal providing substantially the only contact in sealing between the piston and the cylinders. The seal is formed of a relatively soft, elastomeric material which is normally of a plainer, annular shape. Along with a rigid annular ring plate, the elastic ring is sandwiched between the closure member and housing member. The ring plate has a curved surface facing the closure member which serves to backup and support the relatively soft elastic ring under pressure.