Patent ID: 8480884

Claim:
For diesel internal combustion engines, an improved filter unit comprising a cup shaped outer casing ( 2 ) closed on an upper end by a cover ( 3 ) on which a fuel inlet conduit ( 4 ) and a fuel outlet conduit ( 5 ) are positioned, the interior of the casing ( 2 ) being separated by a toroidal filtering baffle ( 6 ) into a first and a second separated chambers ( 10 , 11 ) to which the fuel inlet conduit ( 4 ) and the fuel outlet conduit ( 5 ) are connected respectively, the lower end ( 61 ) of the filtering baffle ( 6 ) being supported by a lower surface of the casing ( 2 ); a device ( 9 ) associated with said filter unit for determining the degree of clogging of the filtering baffle ( 6 ); a tube shaped hole ( 20 ) defined in said lower surface of said casing ( 2 ), an outer circumference of the filtering baffle being larger than the tube shaped hole; a support element ( 8 , 100 ) sealingly received in said tube shaped hole and inserted into an axial hole ( 63 ) extending within the filtering baffle ( 6 ) to which the support element ( 8 , 100 ) is sealingly connected, and wherein said device ( 9 ) for determining the degree of clogging of the filtering baffle ( 6 ) is sensitive to the difference between the fuel pressure in said first and second chambers ( 10 , 11 ), is located inside said support element ( 8 , 100 ), wherein the support element together with the device ( 9 ) for determining the degree of clogging is removable from the bottom of the casing ( 2 ) through the tube shaped hole, wherein said device ( 9 ) comprises a cup-shaped body ( 90 ), from a base of which there branches a stem ( 91 ) having a central through hole ( 92 ), wherein the stem ( 91 ) is inserted into a central hole ( 81 ) in a cover ( 82 ) of the support element ( 8 , 100 ) and the opposite end of the cup-shaped body ( 90 ) is inserted into a hole in a portion ( 80 ) of the support element ( 8 , 100 ), and wherein the cup-shaped body ( 90 ) accommodates an axially slidable piston ( 93 ), which divides the interior of the cup shaped body ( 90 ) into two non-communicating chambers ( 12 , 13 ), including a third chamber ( 12 ) communicating with the first chamber ( 10 ) via the hole ( 92 ) of the stem ( 91 ) and a fourth chamber ( 13 ) communicating with the second chamber ( 11 ) via an additional hole ( 83 ) present in the support element ( 8 , 100 ).