| 摘要 |
PROBLEM TO BE SOLVED: To improve the operation reliability of a pump by imparting, to at least either a membrane or a center duct, such a shape as to prevent a sealed annular zone, which hinders the outflow of a metered and distributed material present in the pump chamber, from being formed between the membrane and the center duct when the volume of the pump chamber decreases. SOLUTION: When a push button 5 is pressed, a center duct 32 causes an end wall 52 of a membrane 50 to move downward, and when elongated, the membrane 50 undergoes elastic deformation to cause the center duct to move. When the push button 5 is moving downward, a metered and distributed substance contained in a pump chamber 34 is discharged into a space between the center duct 32 and the center part 51 of the membrane 50, then arrives at an opening 36, and arrives at an end piece 35 for metering and distribution. When the push button 5 is moving downward, a flexible lip 53 is supported under pressing in the state of being sealed by an inner skirt 20. During this time, a buldge installed in the membrane 50 comes apart from a channel for the metered and distributed substance and thus prevents an annular zone in a sealed state from being formed between the center duct 32 and the center part 51 of the membrane 50. |
