| 摘要 |
<p>The present invention relates to a control device for a controlled non-return valve provided in large hydraulic distributors. During the mode of operation where the double acting hydraulic ram is in a non-movable state, a means is utilized to communicate a control pressure to the one-way non-return check valve to positively maintain the check valve in a closed state thereby eliminating the accidental opening of the return valve and maintaining the double acting hydraulic ram in its initial position.</p> |
