| 摘要 |
<p>There is provided a vortex-valve (40) which comprises a housing defining a vortex chamber (44), the housing having an inlet (46) through which liquid may enter the vortex chamber (44) in a manner to promote swirl within the vortex chamber (44) and an outlet (30) at one axial end of the vortex chamber (44). A wall of the housing is provided with an opening (4) which is normally closed by a closure, this closure (6) being operable between the closed position and an open position in which liquid may enter the vortex chamber (44) by-passing the inlet (46). The vortex-valve (40) may be provided at the outlet of a gully and is useful in enabling a blockage, which may occur at the inlet (46) of the vortex-valve (40), to be by-passed, thereby draining any accumulated liquid in the gully. The blockage may then be removed when the gully is relatively dry.</p> |
