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3-Disk Hydraulic Motor / Pump

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Mouvement de Pascal - The three disks, that are the active elements in the subject mechanism, move in accordance with the following statement: The constant rotation of each disk about a vertical axis through it's centroid, is at half the angular rate of the constant rotation of the centroid about a fixed point.  The result is that each point in the disk traces a planar curve, known as a Limacon of Pascal.

The angled view, at upper right, shows the disk shapes.  The lower [top] view shows disks 1,2, and 3 in initial [A] position, and second [B] position, with centroid advanced 60 degrees about the centroid axis, and orientation advanced 30 degrees about the centroid.



Identity - Below left is a Limacon from a reference text.  At the right is the view of the lower housing of the subject pump, before the ports were cut in and added.  All  three disks are always in contact with the dark, curved surface.  The upper edge, which is always in contact with the horizontal centerline of the disks, has the shape of a Limacon.




Rotor - The rotor turns on an axis through the origin of the Limacon.  Lowest below, is the lower housing, with disks in the valving position.  The second view adds the rotor. The third adds the upper housing



Positive Displacement, Valving, and Continuous Flow -  At the moment in the rotation, shown above, The chamber with curved walls, between two of the disks, is sealed.  Immediately after, The leading disk, acting as a valve, opens the chamber to the outlet port.  Then the trailing disk pushes the chamber contents toward the outlet.  After 60 degrees of rotor rotation, the former trailing disk is now leading the third disk, and the chamber is again sealed.  Thus the flow is continuous, and nearly constant.


The Action -   Note that the extended planes of all three disks, intersect in a singular vertical line.  This line is the axis of the rotor.  The rotor controls the rotation of each disk about its centroid, and the rotation of all three centroids, about the rotor's axis.  The position of each disk, within the plane determined by the rotor, is controlled by the curved cavity in the housings.


Reversibility - This continuous flow, with positive displacement, works equally well with flow in either direction.  Described above as a pump, the device is an equally good hydraulic motor.