Moineau pumping device having a ball coupling
A pumping device is provided which comprises a Moineau pump with a helical rotor inside a helical cavity of a stator, driver means, and a drive connecting rod coupled by a respective coupling to a driving shaft of the driver and to one end of the rotor. Each coupling comprises a spherical head secured to the connecting rod and housed in a cavity that is cylindrical of revolution with the same diameter as and secured coaxially to the end of the rotor of the driving shaft; and a ball housed partly in a cup of the spherical head with its axis perpendicular to the axis of the connecting rod and partly in a lateral recess of the cavity.
1. A pumping device comprising a pump with progressive cavities or Moineau pump with a helical rotor inside a helical cavity of a stator, drive means with a driving shaft roughly coaxial with the cavity of the stator, and a drive connecting rod which is inserted between the driving shaft of the drive means and one end of the rotor to both of which it is coupled by respective coupling means arranged so that said connecting rod follows rotation of the rotor about its own axis, and rotation of the axis of the rotor about the axis of the cavity of the stator,
wherein each of said coupling means comprises
a spherical head secured to the connecting rod at the rotor end or the driving shaft end, respectively,
a cavity that is cylindrical of revolution with the same diameter as said spherical head so as to accommodate the latter and secured coaxially to the rotor end or the driving shaft end of the connecting rod, respectively, and
a ball housed, in part, in a cup in the shape of a spherical cap of a complementary shape made in the spherical head which is arranged in such a way that its axis is roughly perpendicular to the axis of the connecting rod at the rotor or at the driving shaft end respectively and, in part, in a lateral recess of complementary dimensions made in the cavity that is cylindrical of revolution,
whereby the ball forms an offset rotary articulation of said spherical head about a center of said ball compatible with the movement of the double rotation inherent to the Moineau pump and allowed the connecting rod to be inclined appreciably with respect to the end of the rotor or of the driving shaft, respectively, as the driving shaft that drives the rotor rotates.
2. The pumping device according to claim 1 , wherein the spherical head is secured to said connecting rod, and wherein the cavity that is cylindrical of revolution is provided on the end of the rotor and on the drive shaft, respectively.
3. The pumping device according to claim 2 , wherein said connecting rod comprises a rigid bar forming the shank of the rod, to the respective ends of which two spherical heads are secured.
4. The pumping device according to claim 1 , wherein said cavity that is cylindrical of revolution is defined in a hollow sleeve secured to the end of the rotor or to the end of the driving shaft, and wherein said lateral recess provided in said cavity is defined by a hole passing radially through the lateral wall of said sleeve and by a ring attached to the outer wall of said sleeve to externally close said hole.
5. The pumping device according to claim 4 , wherein said outer ring is fixed to the sleeve by at least one radial screw.
6. The pumping device according to claim 1 , wherein the annular part of the inner wall of the sleeve situated between said lateral recess and the end of the sleeve is of frustoconical shape.