Patent EP-1835207-A1 (EP)
Inventor: GRUBER-NADLINGER THOMAS
IPC: F16J15/44
Filed: 2007-02-13
Abstract: The shaft seal for sealing a gap between rotating- and standing components or between two sealing components (1, 2, 5, 7) in a paper machine, comprises a magnetic couple provided to adjust the width of the sealing gap (8), and a pressure spring (6), which exerts a tension force on the sealing components, which act against the force of the magnetic couple. The sealing components rotate at different speeds and are non-rotatably or rigidly attached to or integrated with one another. The magnets of the magnetic couple are attached to or integrated into the sealing components. The shaft seal for sealing a gap between rotating- and standing components or between two sealing components (1, 2, 5, 7) in a paper machine, comprises a magnetic couple provided to adjust the width of the sealing gap (8), and a pressure spring (6), which exerts a tension force on the sealing components, which act against the force of the magnetic couple. The sealing components rotate at different speeds and are non-rotatably or rigidly attached to or integrated with one another. The magnets of the magnetic couple are attached to or integrated into the sealing components and exert an attractive or repulsive force to one another. The sealing components form a labyrinth-shaped or partially labyrinth-shaped sealing gap and have a hollow shaft or solid shaft rotating around a vertical axis of the components, and a vertical housing that supports the shaft or vertical stands, which support the shaft. The sealing components are arranged in such a manner that the components are relatively axially displaceable to one another due to thermal expansion and the magnitude of the relative displacement amounts to a multiple of the width of the sealing gap along the axial direction of the components, for example 10 millimeters. The shaft or solid shaft is a bearing of a paper machine roller. The sealing gap is limited to greater than 0-1 millimeter by arrangement and sizing of the sealing components, the magnetic couple and the pressure spring. The sealing components are designed in the form of concentric rings, and the magnetic couple is designed as permanent magnets having ring-shaped magnets, which concentric to the axis of rotation. The magnets are arranged in such a manner that the north-north or south-south poles of the magnets face to one another or are sequentially arranged along the axial direction of the components. The magnets exhibit a strongly diminishing characteristic curve of the repulsive force along the distance to one another, so that with decreasing distance, the repulsive force increases. The pressure spring exhibit a strain-independent tension force. The pressure spring is formed by additional magnetic couples with a direction of action of the force that is opposite to the direction of action of the force of the magnetic couple, which encloses the sealing gap. The magnetic couple comprises a deactivatable electromagnet to close the sealing gap through deactivation of the magnetic force by the pressure spring during standstill of the components, or within a specified relative range of rotational speed of the components, and an electromagnet, whose magnetic force is adjustable to change and/or to close the extension of the sealing gap as a function of the relative rotational speed between the components by variable adjustment of the magnetic force. The closing of the sealing gap takes place by reversing the polarity of the magnets. The electromagnet is connected to a generator, whose rotor rotates at a speed that is similar to or is a function of the speed of the rotating component to automatically regulate the magnetic force as a function of the rotational speed. The generator is integrated in the shaft seal or the rotor of the generator is non-rotatably attached to or integrated into the rotating component. The sealing components have a component, which is tiltable and/or displaceable along the axis of rotation at an axially intersecting plane and which is held at a specified distance to the other sealing component by the magnetic couple and the pressure spring for tilting and/or shifting motion of the other sealing component. An independent claim is included for a paper machine.