초록 ▼

A pump assembly (1) for an atomizing piston pump comprising a piston (16) slidably located in a cylinder (4), a variable volume fluid storage chamber (5) in communication with the cylinder on one side of the piston, means (18) for varying the volume of the chamber, resilient means (17) urging the va

A pump assembly (1) for an atomizing piston pump comprising a piston (16) slidably located in a cylinder (4), a variable volume fluid storage chamber (5) in communication with the cylinder on one side of the piston, means (18) for varying the volume of the chamber, resilient means (17) urging the varying means into a position corresponding to the minimum volume of the chamber, a fluid flow passageway (30, 31) through the piston, a resilient valve member (25) normally closing the passageway and deforming means (23) for deforming the valve member so as to open the passageway only after the piston has moved relative to the cylinder by a predetermined amount greater than zero. The pump assembly has application to dispensing metered doses of medicinal products and ensures that the dispensed dose is independent of finger pressure applied to the actuator.

대표청구항 ▼

A pump assembly for an atomising piston pump comprising a piston slidably located in a cylinder, a variable volume fluid storage chamber in communication with the cylinder on one side of the piston, means for varying the volume of the chamber, resilient means urging the varying means into a position

A pump assembly for an atomising piston pump comprising a piston slidably located in a cylinder, a variable volume fluid storage chamber in communication with the cylinder on one side of the piston, means for varying the volume of the chamber, resilient means urging the varying means into a position corresponding to the minimum volume of the chamber, a fluid flow passageway through the piston, a resilient valve member normally closing the passageway and deforming means for deforming the valve member so as to open the passageway only after the piston has moved relative to the cylinder by a predetermined amount greater than zero, the piston including a cylindrical surface in which an aperture of the passageway is formed, the resilient valve member including a sleeve portion which overlays the cylindrical surface where it normally obturates the aperture, the sleeve portion is axially compressible by the deforming means so as to at least partially uncover the aperture to open the passageway, the resilient valve member is movable with and mounted coaxially on the piston and further comprises a piston ring portion of larger radius than the sleeve portion, the piston ring portion forming a circumferentially complete seal between the piston and the cylinder throughout at least part of the piston stroke.