| 摘要 |
<p>A gate valve 1 comprises a valve body having a passageway 3, a valve housing 4 and a valve assembly comprising a valve stem 6 carrying a gate 7. The valve stem 6 has threads 9 engaging a spindle nut 10. The upper part 11 of the valve stem 6 has circumferential grooves (13, Fig. 2) engaging complementary surfaces on an encircling collar 12.</p> |
