Patent ID: 6514108
Filing Date: 2003-02-04
Classification: B63H

Abstract:
An ocean-going ship, said ship comprising:a propeller; a shaft mounted for rotation of said propeller; bearing means to journal said shaft; a bushing mounted on said shaft; said bushing having a first end immersed in water when said ship is afloat on water, and a second end opposite said first end near said bearing means; a plurality of seals mounted on said bushing; said plurality of seals comprising lip seals; a plurality of annular elements to maintain said plurality of seals in spaced apart relationship on said bushing; said plurality of annular elements being configured and disposed to provide a plurality of first annular chambers for lubricant to lubricate at least said bearing means; said bushing comprising an annular surface at said second end thereof; said annular surface at said second end of said bushing being configured and disposed to form a portion of a second annular chamber for lubricant to lubricate said bearing means; said plurality of seals being configured and disposed to minimize ingress of water and to retain lubricant for said bearing means in said second annular chamber; at least one seal of said plurality of seals being configured and disposed adjacent to said bearing means; a sensor; said sensor being configured and disposed to sense at least one parameter representative of pressure variations of a lubricant in said second annular chamber due to axial oscillations of said shaft; said sensor being further configured to produce a signal representative of pressure variations of a lubricant in said second annular chamber due to axial oscillations of said shaft; a comparator element; said comparator element being configured and disposed to receive signals representative of pressure variations of a lubricant in said second annular chamber due to axial oscillations of said shaft; said comparator element further being configured to compare signals representative of pressure variations of a lubricant in said second annular chamber due to axial oscillations of said shaft with desired pressure conditions; a control element; said control element being configured and disposed to receive signals from said comparator element to effectuate compensation for pressure variations of a lubricant in said second annular chamber due to axial oscillations of said propeller shaft; an expandable and contractable element; said expandable and contractable element being configured to be filled with a pressure medium and to exert pressure on a lubricant in said second annular chamber to compensate for pressure variations of a lubricant in said second annular chamber due to axial oscillations of said propeller shaft; said comparator being further configured to pass signals, to said control element, to effectuate compensation for pressure variations of a lubricant in said second annular chamber due to axial oscillations of said propeller shaft; and said control element being configured to control the extent of filling of said expandable and contractable element to thus adjust pressure conditions exerted upon a lubricant in said second annular chamber with a phase shift of approximately 180 degrees for an actual lubrication pressure condition in said second annular chamber; thus forming an arrangement to compensate and to minimize lubrication pressure fluctuations, of a ship's stern tube seal arrangement, due to axial oscillations of said propeller shaft.