Position precedence rule. When resolving the float box position, the optimum vertical constraint takes precedence over the optimum horizontal constraint.
位置优先原则：在判断浮动框位置时，最佳垂直限制优于最佳水平限制。
2
The FV-4M1 should be mounted only in a vertical position as its operation is based on the vertical movement of the float (see Fig. 3).
排气阀FV-4M1只能采用直立安装方式，因为其工作原理是以浮子垂直上下运动为基础的（参阅图3）。
3
The position of the float on the riser should be fixed through calculation and site test and adjusted when necessary.