Ejector piston
AssigneeS.A. des Anciens Etablissements Paul Wurth
InventorPierre H. Mailliet
Life of this patent
Estimating the term…
Abstract
Leakage of viscous material past an ejector piston, for example the piston of a clay gun employed in plugging blast furnace tapholes, is eliminated by a piston and ring design which exposes in excess of 50% of the leading and inner diameter surfaces of an expandable ring directly to the viscous material. Also, the leading face of the piston ring is outwardly inclined in the direction of piston travel and a complementary surface to this inclined face is provided on the piston. Expansion of the ring results from the reaction on the inclined face and inner diameter of the pressurized viscous material.
Claims31
In an apparatus for use in the dispensing of viscous material, the apparatus including a cylinder having a longitudinal axis from which the material is expelled under pressure via an opening of reduced diameter, an improved ejector piston for installation in the cylinder comprising:
- a piston body;
- holding plate means, said holding plate means being affixed to said piston body at the forward end thereof in the direction of piston travel during the delivery stroke to expell material from the cylinder, said holding plate means cooperating with said piston body to define a groove about the periphery of said piston body, said groove having a base portion and outwardly extending wall portions, said holding plate means at least in part defining a plurality of circumferentially spaced flow paths through said plate means for material in the cylinder in front of the piston body, said flow paths directly communicating with the base of said groove;
- and
- piston ring means disposed in said groove, said piston ring means including at least one ring member having a leading face inclined radially outwardly and forwardly with respect to said axis, a portion of said ring member inclined leading face being directly exposed to material in the cylinder via said flow paths, a portion of said piston ring means facing the base portion of said groove also being directly exposed to material in the cylinder via said flow paths.
Dependencies are inferred from the claim text.