| 摘要 |
A dispenser has a piston (4) slidable in a first cylinder (11) connected to a second cylinder (12) of smaller diameter. A first tubular member connected to the piston provides a discharge passage and a second tubular member extends through the first cylinder into the second cylinder during the actuating stroke. A sliding seal is formed between the second tubular member and the second cylinder and an aperture (26) provided in the second tubular member acts as both inlet and outlet port during the actuating stroke and return stroke respectively. A valve member (31) controls direction of flow through the aperture and is axially movable by a stem extending through the first tubular member and connected to an actuator (60). Lost motion between the piston and stem provides automatic actuation of the valve member and can be selectively locked to provide locking means preventing discharge. The pump dispenser is particularly suited for dispensing lotions. |
