| 摘要 |
A dispensing apparatus for dispensing a product from a container under pressure of a propellant by means of a composite piston (138). The apparatus has a valve (104) operated by means of an actuator (108) and a lever (166). The actuator cooperates with the valve and lever by means of a screw thread arrangement (110), such that turning actuator relative to the lever varies the flow rate of product out of the apparatus. The valve is a hollow cylindrical tube (104) which is open at one end and closed at the second end, either permanently or by means of a flap valve (112) which allows insertion of the product. A number of ports (116) are arranged around the circumference of the tube (104) adjacent to the second end to allow product to flow through the valve when the lever is operated. The composite piston (138) comprises a first piston (140a) coupled to a second piston (140b) by mutually engageable central stems (142a, b) and enclosing between the pistons a viscous substance which contacts the inside wall of the container to provide an effective seal. The piston arrangement of the apparatus stays together without the need for "necking in" the can and the apparatus can be filled with product by the manufacturer. |
