| 摘要 |
<p>The door (1) has flaps (1a, 1b) articulated on hinges to release sufficient passage to extract or install an equipment (5) such as lifting pump and agitator, when the flaps are opened. One of the flaps is an operating flap with low width to release narrow operating passage in open position to prevent fall of a person, and the other flap with large width allows passage of a flexible link device such as cable and arm of an operator. An automatic locking mechanism prevents opening of the latter flap. Independent claims are also included for the following: (1) a method for extracting an equipment at bottom of a hollow space through an opening provided with a trap door (2) a method for repositioning an equipment in at bottom of hollow space through an opening provided with a trap door.</p> |
