坐落短节的底部“不过”台肩上。“不过”台肩可阻止向下的移动，但阀并未锁

坐落短节的底部“不过”台肩上。“不过”台肩可阻止向下的移动，但阀并未锁紧在短节中。 以阻止向上的移动。止回阀在收回操作中靠移动打开大旁通口来保持平衡。

It sits on the "but" shoulder at the bottom of the nipple. The "however" shoulder prevents downward movement, but the valve is not locked in the nipple. To prevent upward movement. The check valve is balanced by moving and opening the large bypass port during the retraction operation.

Located at the bottom of the nipple "but" on the shoulder. However, the shoulder can prevent downward movement, but the valve is not locked in the nipple. To prevent upward movement. The check valve is balanced by moving to open the large bypass port in the retraction operation.