| 摘要 |
A pump-type dispenser for a fluid product is described which incorporates a single outlet check valve and a follower piston slidably mounted therewithin. The dispenser includes an axially extending bore of a tubular container body for housing a product to be dispensed and having an upper end from which the product is dispensed and an open lower end. The follower piston is slidably mounted within the lower end of the bore of the container body to support the product thereabove. The piston is constructed of resilient material and comprises a face portion adapted to contact the product and a peripherally attached sidewall. The sidewall is formed with at least one peripheral contact band conforming to the shape of the cross section of the bore, and having the peripheral contact band dimensioned to provide an interference fit within the bore which exerts a predetermined normal force against the inner surfaces of the bore in static condition, thereby establishing a predetermined frictional resistance to movement of the piston within the bore. The predetermined frictional resistance is substantially equivalent in both upward and downward directions of axial displacement of the piston within the bore. |
