Abstract: A coupling is provided preferably for a vortex valve for use on an outlet pipe in a sewerage system. The coupling comprises an outer component for insertion into a bore of a pipe, and an inner component which is inserted into the outer component, ramp means being provided between the two components, whereby the outer component is expanded to seal against the bore when the inner component is inserted into the outer component so as to engage the second ramp portion. The ramp means comprise first and second portions of different inclinations. The vortex valve has a circumferential inlet which is adjustable.

Abstract: A coupling is provided preferably for a vortex valve for use on an outlet pipe in a sewerage system. The coupling comprises an outer component for insertion into a bore of a pipe (62), and an inner component (26) which is inserted into the outer component, ramp means being provided between the two components, whereby the outer component is expanded to seal against the bore when the inner component (26) is inserted into the outer component so as to engage the second ramp portion. The ramp means comprise first and second portions (28, 30) of different inclinations. The vortex valve has a circumferential inlet (11) which is adjustable.