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