drop valve meaning in English

(蒸汽机中上下活动的)活门，活阀。

In chapter 4 , the principle drawing of the system is presented after adding a constant - pressure - drop valve . the operating principal of the valve is briefly introduced . the static mathematical model is built up and study is carried out by means of simulation under the circumstance of matlab , then the static working point is obtained
对定差减压阀作了简要的介绍，根据系统工作原理图建立静态数学模型进行仿真研究，由仿真结果分析系统静态工作特性，得到静态工作点；然后，建立系统动态模型，对其动态特性进行非线性仿真研究，并就环境因素变化对系统工作特性的影响作了详细分析。
This paper supplied a new way through variable frequency variable speed ( vfvs ) to change its output flow rate and adding a constant - pressure - drop valve , which could solve the defects in hydraulic pressure servo control system , such as low efficiency in control system , short life , poor ability in resisting pollution , low efficiency in driving system and flow rate , pressure pulse . and this way was proved to be effective
本论文针对传统伺服控制系统效率不高、元件寿命短、抗污染能力差、驱动系统效率低、存在流量及压力脉动等缺陷，利用先进的交流变频调速技术改变液压泵转速的容积调速新方法，提出了在液压系统中加一个定差减压阀的新思路，较好地解决了液压伺服系统存在的上述问题。