A spring-powered jet injector was designed for animal vaccine injection.It has the feature of continuous drug delivery and injection.Several parameters are critical to the injection quality,such as nozzle diameter,volume of drug delivered,ampoule diameter,and jetting force.As two important factors to evaluate the injection quality,the injection pressure determines whether the jet can erode and penetrate

into the skin,and the jet power effectively describes the injection completeness.A physical model was presented to predict the injection pressure and jet power with given system parameters.The model was validated by experimental results.Finally,an example was given to determine the system variables through calculation.

设计了一种以弹簧为动力、可以连续吸药及注射的无针注射系统,影响无针注射质量的主要系统参数有喷孔直径、药物注射剂量、活塞（安瓿）直径、推射力等。喷射穿刺能力与注射完全度是对动物疫苗进行无针注射质量评价的重要指标,与喷射最大压力和喷射功率相关。给出了在给定系统参数情况下预测喷射压力与喷射功率的物理模型,并用实验验证了模型的正确性。最后通过计算给出了确定系统参数的一个实例。

无针注射, 喷射, 滞止压强, 疫苗