Patent ID: 8037897

Claim:
A novel valve apparatus having a longitudinal axis therethrough, comprising: a valve seat member that comprises a hollow bore and a first frustoconical contact surface that has an inner perimeter and an outer perimeter; a valve closure member that comprises a valve body and a second frustoconical contact surface that is adapted to seal against the first frustoconical contact surface in a strike face area, the valve closure member being movable along the longitudinal axis of the valve apparatus; a fluid flow path through the bore of the valve seat member and between the valve seat member and the valve closure member, the fluid flow path being closed when the second frustoconical contact surface is in contact with the first frustoconical contact surface; an elastomeric resilient valve insert member attached to the valve body member of the valve closure member, wherein said insert member: (a) has an inner perimeter and an outer perimeter, the inner perimeter being adjacent the strike face area on the second frustoconical contact surface, (b) is offset and adapted to contact the first frustoconical contact surface and form a seal therewith at the outer perimeter of the insert member before the first frustoconical contact surface comes in contact with the second frustoconical surface as the valve closes, and wherein (i) the insert offset of the insert member is greater at its outer perimeter than at its inner perimeter, and (ii) the insert offset of the insert member is greater at its outer perimeter than the diameter of the largest particle in any fluid to be pumped though the bore of the valve seat member, (c) is deformable, but substantially non-compressible, and (d) comprises a particle retaining means to accommodate solid particles that are trapped between the insert member and the valve seat member when the valve closes, said particle retaining means having at least one cavity (void space) that is in fluid contact with the flow path for fluids between the valve seat member and the valve closure member when the valve is open, and wherein said cavity (i) has an opening in fluid contact with the flow path for fluids that is large enough for particles to pass through the opening and into the cavity, (ii) is large enough to accommodate one or more solid particles within the interior of the cavity, and wherein (iii) the volume of the cavity contracts as the valve closes, whereby slurry is forced out of the cavity into the flow path and whereby solid particles are screened from the fluid and retained within the cavity, and clear fluid is directed inwardly toward the hollow bore of the valve seat member over the surfaces of the first and second frustoconical contact surfaces.