| 摘要 |
A trap for a waste outlet for use in drainage facilities is described which provides a water seal. The trap comprises a one-way valve (23) at the trap inlet (14) and a pressure one-way valve (24) at the trap outlet (16) such that, in addition to prevent ingress of animals from the soil pipe to the buildings, prevents ingress of odours and the water seal being sucked away. The pressure valve (24) allows in the presence of a negative pressure differential across the outlet one-way pressure valve that air can pass through the pressure valve (24) to relieve the pressure differential but in the event of a positive pressure differential, air is prevented from passing through the oneway pressure valve (24). |
