When injection of an innerplunger of the refill of the pen insulin syringe stops, the convex plunger is tallied with the top of a refill bottle and fills the whole space.
当笔式胰岛素注射器笔芯内柱塞推注到终止时，凸型柱塞与笔芯瓶顶部相吻合，充满整个空间。
2
A sheath (30) closes the opening (18) and embraces an inner portion of the plunger (25), whereby pumping chamber (33) is defined between the pump body (11) and the sheath (30).