A propulsion unit (1) for a marine vessel, comprising a shell structure (2), a shaft (4) rotatably coupled to a propulsion motor (3) inside the shell structure (2), and a propeller (5) coupled to the shaft (4) outside the shell structure (2). A shaft seal arrangement (6) is provided to engage the shaft (4), such that at least a first seal chamber (6a) is delimited between adjacent seal lips (6′) and the shaft (4). A first lubrication arrangement is provided for circulating a first lubricant through the first seal chamber (6a). The first lubrication arrangement (7) further comprises a first lubricant heat exchanger (7e) arranged at least partly outside of the shell structure (2) for conducting the first lubricant therethrough and for transferring heat from the first lubricant to an outside environment of the shell structure (2). A propulsion unit for a marine vessel, including a shell structure, a shaft rotatably coupled to a propulsion motor inside the shell structure, and a propeller coupled to the shaft outside the shell structure. A shaft seal arrangement is provided to engage the shaft, such that at least a first seal chamber is delimited between adjacent seal lips and the shaft. A first lubrication arrangement is provided for circulating a first lubricant through the first seal chamber. The first lubrication arrangement further includes a first lubricant heat exchanger arranged at least partly outside of the shell structure for conducting the first lubricant therethrough and for transferring heat from the first lubricant to an outside environment of the shell structure.

A method and an arrangement for sealing a propeller shaft located under water. The propeller shaft is arranged at a pod of a ship and an air chamber is provided circumferentially around the propeller shaft. The method includes supplying compressed air from a compressed air source to the air chamber, discharging compressed air from the air chamber in an air return line and colleting liquid present in the compressed air discharged from the air chamber in an intermediate leakage tank that is provided in the air return line. The method includes closing the air return line upstream of the intermediate leakage tank, and supplying compressed air to the intermediate leakage tank to effect flowing of liquid present in the intermediate leakage tank to a leakage tank.

An arrangement and a method for sealing a propeller shaft of a marine vessel. The arrangement including a shaft seal arrangement and a lubrication arrangement including a lubricant circulation line for conducting lubricant to and from the shaft seal arrangement and a lubricant circulator. The lubricant circulation line includes a connection line that is connected in fluid connection with the lubricant circulation line downstream of the lubricant circulator and upstream of the shaft seal arrangement, and that is connected in fluid connection with a second part of the lubricant circulation line so as to selectively conduct a part of the flow of lubricant past the shaft seal arrangement. At least one hydraulically operated pressure relief means is configured to control the flow of lubricant in the connection line.

An arrangement and a method for sealing a propeller shaft of a marine vessel. The arrangement includes a propeller shaft rotatable supported with at least one bearing, a bearing arrangement, a first lubrication arrangement including a first lubricant circulation line for conducting first lubricant to and from the bearing arrangement, a shaft seal arrangement for sealing the propeller shaft against sea water, and a second lubrication arrangement including a second lubricant circulation line for conducting second lubricant to and from the shaft seal arrangement. A first heat exchanger is in thermal contact with the first lubricant circulation line and in thermal contact with the second lubricant circulation line.

A shaft seal includes a shaft engaging portion configured to couple to a shaft extending through a wall. The shaft seal includes a flange configured to sealingly engage the wall. The shaft seal includes a body extending between the shaft engaging portion and the flange. The seal is configured to allow radial and axial movement of the shaft relative to the wall while maintaining a seal between the flange and the wall.

A protective device for a stern tube seal of a propeller-driven vessel, wherein an intermediate space is left open between a stern tube and a propeller hub, which intermediate space is covered by a tubular protective cover concentric with the propeller hub, which protective cover is fixedly anchored to the stern tube and axially overlies the propeller hub leaving an annular gap, wherein a ring concentric with the propeller hub and U-shaped in radial section is disposed inside the protective cover in the intermediate space between the stern tube and the propeller hub, the U-opening of which ring is directed radially outward, and wherein the ring is at least partially formed of a material that has a pourable consistency at 20° C.

This propulsion unit for an aquatic vehicle consists of a mobile casing mounted in a pivot connection in relation to a hull element of the aquatic vehicle, a drive shaft of a propeller, said shaft being mounted rotatably within the mobile casing by means of at least one bearing consisting of a closed space adapted to be filled with a hydraulic fluid, an electrical machine being adapted to drive the rotary drive shaft in relation to the mobile casing, where the propulsion unit further consists of a module for conditioning the hydraulic fluid contained in the closed space of the bearing. The propulsion unit also consists of a control device to control the conditioning, the control device consisting of a temperature sensor and capable of activating the conditioning of the hydraulic fluid contained in the closed space according to the temperature measured by the temperature sensor.

A sealing device for a drive shaft is disclosed and described. The sealing device for a drive shaft comprises a housing disposed to surround the drive shaft between the inner space and the outer space, a plurality of sealing members axially separated from each other between the housing and the drive shaft to seal between the housing and the drive shaft, fixing ring members interposed between the plurality of sealing members to maintain the separation distance between the sealing members, and a fixing member secured to the housing to apply an axial pressure to the plurality of sealing members and fixing ring members, wherein a concave-convex section is formed on at least one of the close surfaces of the fixing ring member and the sealing member, which face each other.

A sealing system for sealing a shaft located under water includes a bush mountable on the shaft and fixed to the shaft, a housing fixed with respect to the bush and surrounding a first portion of the bush, a lubricant chamber and an air chamber in the housing and open to the bush, the lubricant chamber being sealed with respect to the air chamber by a seal ring, a mechanical seal outside the housing and surrounding a second portion of the bush, an air supply line and an air discharge line connected to the air chamber, and a quantity of lubricating oil in the lubricant chamber, the lubricating oil being in fluid communication with a lubricant tank via at least one oil line, wherein an air pressure in the air chamber is greater than an oil pressure in the lubricant chamber.

The invention relates to a ring seal which comprises a main body capable of implementing a seal by static contact relative to a first cylindrical element, and a first circumferential lip capable of engaging by friction with a cylindrical surface of a second cylindrical element, said cylindrical elements being substantially coaxial and mounted so as to pivot relative to one another. The main body comprises a front surface configured to be in axial contact with a front surface of the first cylindrical element, the main body comprising a second circumferential lip radially opposite the first circumferential lip and capable of being in radial contact with a cylindrical surface of the first cylindrical element.