Wafer elements for progressing cavity stators
AssigneeSmith International, Inc.
InventorJohn E. Tschirky
Life of this patent
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Abstract
A progressive cavity motor with a bifoil stator assembled in a straight-sided wafer array and methods of formation of said stators.
Claims19
A stator for a helicoidal progressing cavity transducer comprising a plurality of wafers, each having an internal wall substantially perpendicular to the wafer surface and arranged one after the other in array, each having a bifoil opening of the same geometry and the same height and the same minor and major axis, the axis of each wafer angularly displaced counterclockwise from the like axis of adjacent wafers in the array of wafers, by an angle a in degrees which is given by the formula:
- ##EQU10## where (h) is the thickness of the wafer, (P.sub.s) is the length of one pitch of the stator, and means to securely fasten said wafers to each other in said array.
A method of forming a laminated stator which comprises mounting a form having a helicoidal surface of pitch (P.sub.s) and whose cross section through its length contains a bifoil opening of uniform geometry and dimensions, assembling in a longitudinal array on the said form, a plurality of wafers having an opening of the same bifoil geometry and having an internal surface substantially perpendicular to the wafer surface, and having thickness (h), which is a small fraction of the said pitch (P.sub.s), securing said wafers to each other against angular displacement, removing said form from said longitudinal array.
Dependencies are inferred from the claim text.