The invention refers to a device for separating a surface layer of a liquid by
a container submerged in the liquid. The container includes a bottom, a wall member,
connected to the bottom and having a variable length, and a separating member,
which is connected to the wall member and communicates with a space in the container
via an opening. An overflow portion of the separating member is located below a
free liquid surface of the surface layer and permits the flowing of liquid. A discharge
conduit extends from the space for liquid discharge. A floating member, connected
to the separating member, floats on the liquid outside the container and exerts
a lifting force upon the separating member in a direction prolonging the wall member.
A submerging member is connected to the separating member and located below the
over flow portion. The submerging member has a mass and exerts a downwardly directed
force, so that the overflow portion is located below the free liquid surface, and
a lifting force due to liquid pressure when the space has been filled with such
a quantity of liquid that the submerging member partly is located in the liquid,
wherein the overflow portion will be above the free liquid surface.
