Method and apparatus for sterilization of a centrifugal pump
AssigneeMICI Limited Partnership IV
InventorsEarl W. Clausen, Lloyd C. Hubbard
Life of this patent
Estimating the term…
Abstract
A centrifugal blood pump has a face seal between a pump housing wall and a hub of an impeller which provides upon assembly a gas permeable seal at a seal interface surrounding a shaft defining the rotational axis of the impeller. This seal separates a blood pumping chamber from a separate chamber housing lubricants and bearings for impeller rotation. Prior to rotation of the impeller, the blood pump is sterilized by exposure to ethylene oxide gas which passes through the gas permeable seal interface to also sterilize the interior of the bearing chamber in the pump. Upon rotation of the impeller, the seal interface, which is perpendicular to the axis, is converted to a gas and liquid impermeable seal.
Claims23
A method of forming a gas permeable seal about an opening through a wall and converting that seal into a gas impermeable seal after a desired gas passage through the seal, the method comprising the steps of;
- providing a first seal face fixed with respect to a wall about an opening therethrough;
- covering the opening with a rotatable member having a second seal face in abutment with the first seal face, the first and second seal faces being generally planar with one of said seal faces being smooth and the other seal face being uneven to form a gas permeable seal about the opening through the unevenness of the uneven seal face;
- and
- rotating the rotatable member and second seal face thereon with respect to the first seal face, after said desired gas passage, to burnish the unevennness of the uneven seal face and create a gas impermeable seal between the first and second seal faces about the opening.
A method of forming a gas permeable seal about a shaft which defines a rotational axis and converting that seal into a gas impermeable seal after a desired gas passage through the seal, the method comprising the steps of:
- providing an annular, first seal face around the shaft with the first seal face being generally perpendicular to the rotational axis and fixed with respect to the shaft;
- covering a portion of the shaft with a rotatable hub having a second seal face mounted with respect thereto and in abutment with the first seal face, the first and second seal faces being generally planar with one of said seal faces being smooth and the other seal face being uneven to form a gas permeable seal therebetween through the unevenness of the uneven seal face;
- and
- rotating the hub and second seal face with respect to the first seal face, after said desired gas passage, to burnish the unevenness of the uneven seal face and create a gas impermeable seal between the first and second seal faces.
A centrifugal pump comprising:
- a pump housing;
- wall means for dividing an interior of the pump housing into a drive chamber and a pumping chamber;
- a shaft extending in an axial direction from the drive chamber through the wall means into the pumping chamber to define a rotational axis;
- an impeller mounted with respect to the shaft for rotation about the rotational axis within the pumping chamber, the impeller having a hub;
- seal means between the wall means and the hub for providing a gas permeable seal at a seal interface surrounding the shaft between the drive chamber and the pumping chamber;
- and
- means for converting the seal means into a gas impermeable seal upon rotation of the shaft with respect to the pump housing.
A centrifugal pump comprising:
- a pump housing having a pumping chamber therein;
- a shaft extending in an axial direction from a wall of the pump housing into the pumping chamber to define a rotational axis;
- an impeller for rotation about the rotation axis within the pumping chamber, the impeller having a hub;
- seal means between the wall of the pump housing and the hub for providing a gas permeable seal at a seal interface surrounding the shaft between the pumping chamber and an interior portion of the hub adjacent the shaft;
- and
- means for converting the seal means into a gas impermeable seal upon rotation of the hub with respect to the pump housing.
A method of sterilizing a centrifugal pump for biological fluids, the method comprising the steps of:
- dividing an interior of a centrifugal pump into first and second chambers;
- sealing the first chamber from an exterior of the centrifugal pump except through an opening from the first chamber into the second chamber;
- providing a generally planar first seal face fixed with respect to the opening on one side thereof;
- covering the opening with a rotatable member having a generally planar second seal face in abutment with the first seal face, one of the planar seal faces being smooth and the other planar seal face being uneven relative to the smooth seal face to form a gas permeable seal about the opening;
- and
- exposing the pump and second chamber therein to a medical sterilization gas to contact and sterilize the pump exterior and second chamber and the first chamber through the gas permeable seal and opening into the first chamber;
- the member and second seal face thereon being rotatable with respect to the first seal face to smooth by burnishing the unevenness therebetween and create a gas impermeable seal between the first and second seal faces about the opening.
Dependencies are inferred from the claim text.