This concerns a device whose filtering membrane (4) is gripped annularly at the periphery between an annular transverse wall (32) forming part of a drainage body and an axially oriented cylindrical wall (9) of an intake body, which lateral wall has an elastomer seal (13) which forms the edge thereof and by means of which this wall comes into contact with the membrane (4), this device being provided with a second seal (55) which has an arched profile, the external annular end (61) of which bears against said annular transverse wall (32) radially beyond said membrane (4), and the internal end (57) of which is connected to said seal (13) on the lateral wall (9) of said reservoir (5), hereinafter referred to as the first seal.