(57) The invention is concerned with an interceptor tank, of the kind installed in drainage
systems such as at garages, to prevent liquid of low specific gravity such as oil
or petrol from being discharged with surface water into the sewage system. In accordance
with the invention an interceptor tank (6) is divided into three generally superposed
separation chambers (8,10,12) by partitions (14,16). Inlet means (42) is provided
by which water containing petrol or oil is delivered to the lowermost chamber (8),
the partitions being provided with apertures (26, 28) whereby water may pass upwardly
from the lowermost to successively higher chambers, and through an outlet (38). A
supplementary compartment (18) is provided, which is connected to the chambers in
a manner whereby liquid of a specific gravity less than 1 may flow therefrom into
the supplementary compartment, the supplementary compartment having an outlet (48)
through which low s.g. liquid may flow, which is positioned at a level higher than
the outlet (38) from the uppermost chamber. Liquid from the supplementary chamber
(18) flows through the outlet (48) into a collection chamber (50) from which water
may be removed from the lower part, and low s.g. liquid from the upper part.
|
|
