Also, the annular BOP is used to locate the position of tooljoints or drill collars (by pulling through the closed element until an increase in the pulling force is required).

• 在浮式钻井操作中，这一特性允许即使钻柱由于浮动设备的升沉运动而在关闭的元件中往复运动时环形防喷器也能被关闭和发生作用。