Propeller arrangement in a cathodic protection system
The invention relates to a propeller arrangement in a cathodic protection system for a marine vessel with a marine propulsion system, which cathodic protection system comprises a direct current power source with a positive terminal. The propulsion system comprises at least one driveline housing at least partially submerged in water; a torque transmitting drive shaft extending out of the driveline housing; and at least one propeller mounted on the drive shaft. According to the invention, the at least one propeller is electrically isolated from its drive shaft. Each electrically isolated propeller is electrically connected to a slip ring connector, which slip ring connector is in electrical connection with the positive terminal. The invention further relates to a vessel provided with such a propeller arrangement.
1 . Propeller arrangement in a cathodic protection system for a marine vessel with a marine propulsion system, which cathodic protection system comprises a direct current power source; the propulsion system comprising;
at least one driveline housing at least partially submerged in water;
a torque transmitting drive shaft extending out of the driveline housing;
at least one propeller mounted on the drive shaft;
wherein
the at least one propeller is electrically isolated from its drive shaft in an interface between an outer circumferential surface of the drive shaft and an inner circumferential surface of the propeller;
each electrically isolated propeller is electrically connected to a slip ring connector; which slip ring connector is in electrical connection with a terminal of the direct current power source.
2 . Propeller arrangement according to claim 1 , wherein each propeller hub has a slip ring connector attached to the hub upstream in the power flow direction.
3 . Propeller arrangement according to claim 1 , wherein the slip ring connector is annular and arranged surrounding and spaced from the drive shaft.
4 . Propeller arrangement according to claim 1 , wherein the slip ring connector is mounted onto an internal surface at one end of the propeller hub.
5 . Propeller arrangement according to claim 1 , wherein the slip ring connector is mounted between a first propeller hub and the driveline housing.
6 . Propeller arrangement according to claim 5 , wherein a further slip ring connector is mounted between a first propeller hub and a second propeller hub.
7 . Propeller arrangement according to claim 1 , wherein each slip ring connector is made from an inert metallic material.
8 . Propeller arrangement according to claim 1 , wherein the at least one propeller is made from an inert metallic material.
9 . Propeller arrangement according to claim 1 , wherein a torque transmitting electrically isolating component is mounted between the at least one propeller and the drive shaft.
10 . Propeller arrangement according to claim 1 , wherein a dielectric shield is provided between the at least one propeller and the drive shaft.
11 . Propeller arrangement according to claim 10 , wherein the dielectric shield comprises a layer of dielectric material extending along the drive shaft over at least the entire axial extension of the propeller hub.
12 . Propeller arrangement according to claim 1 , wherein slip ring connector is in electrical connection with a positive terminal of the direct current power source, so that the at least one propeller forms an anode.
13 . Propeller arrangement according to claim 1 , wherein slip ring connector is in electrical connection with a negative terminal of the direct current power source so that the at least one propeller forms a cathode.
14 . Marine vessel wherein the marine vessel is protected by a propeller arrangement according to claim 1 .