Liquid filter with connection flange

A combination of a filter and a connection flange, the combination comprising:

• a filter comprising a filter housing comprising an inner end for connection to a connection flange and an outer end connected to a detachable cover, the inner end comprising a filter inlet duct, a filter return duct and a plurality of coaxially spaced radial filter seals for providing a seal between the filter housing and the connection flange, the filter further comprising a removable filter insert;
• the connection flange comprising a connection inlet duct in matching registry with the filter inlet duct and a connection return duct in matching registry with the filter return duct, the connection flange further comprising a plurality of coaxially spaced sealing surfaces, each sealing surface being in matching registry with one of said radial filter seals;
• the radial filter seals comprising a first radial filter seal and a second radial filter seal;
• the filter return duct is defined by a first cylindrical wall surrounding a first axis having a first radially outer surface with a first peripheral groove therein for accommodating the first radial filter seal, the connection return duct comprising a first radially inwardly facing sealing surface, the first cylindrical wall and the first radial filter seal matably engaging the first radially inwardly facing sealing surface of the connection return duct of the connection flange;
• a second cylindrical wall surrounding said first cylindrical wall, the filter inlet duct is disposed between the first cylindrical wall and the second cylindrical wall, the second cylindrical wall comprising a second radially outer surface with a second peripheral groove therein for accommodating the second radial filter seal, the connection inlet duct comprising a second radially inwardly facing sealing surface, the second cylindrical wall and the second radial filter seal matably engaging the second radially inwardly facing sealing surface of the connection inlet duct of the connection flange, wherein said filter housing can be rotated about said first axis with respect to said connection flange to a plurality of angular positions;
• and
• locking means for securing the filter housing against the connection flange, wherein said locking means secures said filter housing against rotation about said first axis with respect to the connection flange, and wherein said locking means permits said filter housing to be rotationally secured at a plurality of said angular positions with respect to said connecting flange.