Magnetically suspended and rotated rotor

An artificial heart for implantation in the body of a human subject comprising:

• a first pump comprising a housing constructed of or coated with a blood compatible material having an inlet passage fluidly connectable to the subject's left atrium and an outlet passage fluidly connectable to the subject'aorta;
• and
• a second pump comprising a housing constructed of or coated with a blood compatible material having an inlet passage connectable to at least one of the subject's superior vena cava and inferior vena cava and an outlet passage fluidly connectable to the subject's pulmonary artery;
• wherein the housing of each of said pumps has an impellor chamber disposed between the housing inlet passage and the housing outlet passage;
• and wherein each of said pumps further comprises:
• an impellor disposed in the housing impellor chamber and rotatable therein about an impellor rotation axis for drawing blood from the housing outlet passage;
• magnetic suspension means disposed partially on the impellor and partially on the housing for magnetically suspending the impellor in said impellor chamber out of contact with the walls of the pump chamber, comprising:
• permanent magnet impellor means comprising an assembly of permanent magnets mounted on the impellor and on the housing for exerting forces on the impellor tending to align the rotation axis of the impellor with a selcted support axis of the housing while tending to drive the impellor axially away from a selected null position on said support axis at such times that the impellor is axially displaced from the null position;
• an electromagnet mounted on the housing and positioned thereon to exert a force directed along the support axis on portions of the permanent magnet impellor support means disposed on the impellor at such times that an electric current is passed through the electromagnet, the electromagnet thereby exerting an axial force on the rotor;
• and
• electromagnet control means mounted on the housing for detecting a displacement of the impellor from a control position of the impellor on the support axis and passing a current through the electromagnet to drive the impellor toward the control position;
• and
• impellor drive means disposed partially on the impellor and partially on the housing for turning the impellor about said rotation axis, wherein portions of the impellor drive means disposed on the impellor are coupled solely magnetically to portions of the impellor drive means disposed on the housing.

A pump for pumping blood implantable in the human body to provide a replacement for, or an assist to, the natural heart, comprising:

• a housing constructed of or coated with a blood compatible material having an inlet passage and an outlet passage for connecting the pump into the circulatory system of the person into which the pump is implanted, the housing having an impellor chamber fluidly interposed between the inlet passage and the outlet passage;
• an impellor constructed of or coated with a blood compatible material disposed in the housing impellor chamber and rotatable therein about an impellor rotation axis for drawing blood into the housing inlet passage and discharging blood from the housing outlet passage;
• magnetic suspension means for magnetically suspending the rotor in said pump chamber out of contact with the walls of the impellor chamber, comprising:
• permanent magnet impellor support means comprising an assembly of permanent magnets mounted on the impellor and on the housing for exerting forces on the impellor tending to align the rotation axis of the impellor with a selected support axis of the housing while tending to drive the impellor axially away from a selected null position on said support axis at such times that the impellor is axially displaced from the null position;
• an electromagnet mounted on the housing and positioned thereon to exert a force directed along the support axis on portions of the permanent magnet impellor support means disposed on the impellor at such times that an electric current is passed through the electromagnet, the electromagnet thereby exerting an axial force on the rotor.
• electromagnet control means mounted on the housing for detecting a displacement of the impellor from a control position of the impellor on the support axis and passing a current through the electromagnet to drive the impellor toward the control position;
• impellor drive means mounted on the housing for sensing the pressure in the inlet passage of the housing related to the flow of blood in the circulatory system and magnetically coupled to the impellor for rotating the impellor at a rate varying in accordance with a selected relationship to the value of the pressure in the inlet passage of the housing;
• and wherein the combined center of gravity of the impellor and portions of the impellor drive means and permanent magnet impellor support means disposed thereon is positioned at the center of buoyancy of the impellor, and wherein a cavity is formed in the impellor to match the average specific gravity of the impellor and portions of the drive means and the permanent magnet impellor support means thereon to the specific gravity of blood.

A pump implantable in the human body to provide a replacement for, or an assist to, the natural heart, comprising:

• a housing constructed of or coated with a blood compatible material having an inlet passage and an outlet passage for connecting the pump into the circulatory system of the person into which the pump is implanted, the housing having an impellor chamber fluidly interposed between the inlet passage and the outlet passage;
• an impellor constructed of or coated with a blood compatible material disposed in the housing impellor chamber and rotatable therein about an impellor rotation axis for drawing blood into the housing inlet passage and discharging blood from the housing outlet passage;
• magnetic suspension means for magnetically suspending the rotor in said pump chamber out of contact with the walls of the impellor chamber, comprising:
• permanent magnet impellor support means comprising an assembly of permanent magnets mounted on the impellor and on the housing for exerting forces on the impellor tending to align the rotation axis of the impellor with a selected support axis of the housing while tending to drive the impellor axially away from a selected null position on said support axis at such times that the impellor is axially displaced from the null position;
• an electromagnet mounted on the housing and positioned thereon to exert a force directed along the support axis on portions of the permanent magnet impellor support means disposed on the impellor at such times that an electric current is passed through the electromagnet, the electromagnet thereby exerting an axial force on the rotor,
• electromagnet control means mounted on the housing for detecting a displacement of the impellor from a control position of the impellor on the support axis and passing a current through the electromagnet to drive the impellor toward the control position;
• comprising:
• means for selecting the control position in a displaced relationship to the null position along said support axis, whereby the permanent magnet impellor support means will exert a force on the impellor at such times that the impellor is in the control position, thereby enabling the permanent magnets of the permanent magnet impellor support means to balance a static force exerted axially on the impellor;
• impellor drive means mounted on the housing for sensing a preselected physical quantity related to the flow of blood in said circulatory system and magnetically coupled to the impellor for rotating the impellor at a rate varying in accordance with a selected relationship to the value of said quantity;
• and wherein the combined center of gravity of the impellor and portions of the impellor drive means and permanent magnet impellor support means disposed thereon is positioned at the center of buoyancy of the impellor, and wherein a cavity is formed in the impellor to match the average specific gravity of the impellor and portions of the drive means and the permanent magnet impellor support means thereon to the specific gravity of blood.