Abstract: Recovery time of hydraulic lock is influenced by many factors, which is often required to be controlled in an exact range during the practical use. On the basis of analysing the operational principle for the hydraulic lock, the cause of the datum discreteness for the recovery time is found out, it is that the control rod in the hydraulic lock affected the effective flow area of the throttle gate. Through the establishment of the hydraulic oil channels physical model and mathematical model as well as the further calculation and analysis, it is concluded that the throttle gate and the annular gap are the most important factors to the recovery time. The datum of the recovery time are clarified to be in line with the requirements of the design criterion by choosing the proper parameters for the throttle gate and the annular gap. The accuracy of the calculation results is finally verified through experiments.

Key words: Annular gap, Hydraulic oil channels Throttle gate, Recovery time