Pumps

Claim 1

A pump including: a. a reservoir for receiving materials to be pumped, b. a cylinder disposed below the reservoir, c. intake conduits connecting each end of the cylinder and the reservoir for permitting flow of material from the reservoir to the cylinder, d. discharge manifold having a discharge opening disposed adjacent the cylinder, e. discharge conduits connecting each end of the cylinder with the manifold for enabling flow of material from the cylinder to the manifold, f. a double-headed piston assembly mounted in the cylinder for reciprocal movement, said piston assembly including: i. a piston disposed axially of the cylinder and being of smaller diameter than the cylinder and having axially disposed cylindrical projections at each end thereof, ii. a cylindrical guide mounted on the cylindrical projection slideably engaging the cylinder walls, iii. oil passages extending through an opening out of opposite faces of the guide, iv. a felt washer having slideable fit with the cylinder mounted on the projection against the outer face of the guide, v. a pressure washer against the outer face of the felt washer, vi. a piston cup formed of a flexible material mounted on the projection against the pressure washer, vii. an expansion washer fitted over the projection against the cup, viii. a nut threaded on the projection adapted to be tightened against the expansion washer so as to obtain radial expansion of the expansion washer against the cup and radial expansion of the felt washer against the cylinder, g. means for reciprocating the piston, h. check valve assemblies in the intake and discharge conduits for preventing return flow of material from the cylinder back to the reservoir and for preventing return flow of fluid from the manifold back to the cylinder so that material is drawn from the reservoir and pumped into the manifold at each stroke of the piston assembly.