Impeller housing
Apparatus and methods are described including manufacturing a housing for an impeller of a blood pump by placing an inner lining around a mandrel, placing a cylindrical portion of a frame around the inner lining, and placing a distal portion of an elongate tube around a portion of the frame. While the distal portion of the elongate tube is disposed around the portion of the frame, the inner lining, the frame, and the distal portion of the elongate tube are heated, via the mandrel, and pressure is applied from outside the distal portion of the elongate tube, such as to cause the distal portion of the elongate tube to conform with a structure of the struts of the frame, and to cause the inner lining and the distal portion of the elongate tube to become coupled to the frame. Other applications are also described.
1. A method, comprising:
manufacturing a housing for an impeller of a blood pump by:
placing an inner lining around a mandrel;
placing a cylindrical portion of a frame around the inner lining, the cylindrical portion of the frame including struts that define a generally cylindrical shape;
placing a distal portion of an elongate tube around at least a portion of the frame, the elongate tube including a proximal portion that defines at least one blood outlet opening;
while the distal portion of the elongate tube is disposed around at least the portion of the frame, heating the inner lining, the frame and the distal portion of the elongate tube, via the mandrel; and
while heating the inner lining, the frame, and the distal portion of the elongate tube, applying pressure from outside the distal portion of the elongate tube, such as to cause the distal portion of the elongate tube to conform with a structure of the struts of the frame, and such as to cause the inner lining and the distal portion of the elongate tube to become coupled to the frame.
2. The method according to claim 1 , further comprising, subsequent to causing the inner lining and the distal portion of the elongate tube to become coupled to the frame, shaping a distal end of the frame to define a widened inlet.
3. The method according to claim 1 , further comprising, subsequent to causing the inner lining and the distal portion of the elongate tube to become coupled to the frame, shaping a portion of the frame to form a converging region, such that the frame defines a narrowing in a vicinity of a location within the frame that is configured to house the impeller.
4. The method according to claim 1 , wherein:
the inner lining and the elongate tube include an inner lining and elongate tube that are made from different materials from each other, and a thermoforming temperature of a material from which the inner lining is made is higher than a thermoforming temperature of a material from which the elongate tube is made, and
heating the inner lining, the frame, and the distal portion of the elongate tube comprises heating the inner lining, the frame, and the distal portion of the elongate tube to a temperature that is above the thermoforming temperature of the material from which the elongate tube is made and below the thermoforming temperature of the material from which the inner lining is made.
5. The method according to claim 1 , wherein applying pressure from outside the distal portion of the elongate tube comprises applying pressure from outside the distal portion of the elongate tube using an outer tube that is made of silicone.
6. The method according to claim 1 , wherein placing the distal portion of the elongate tube around at least a portion of the frame comprises placing the distal portion of the elongate tube around the entire cylindrical portion of the frame, such the distal portion of the elongate tube overlaps with the entire inner lining.
7. The method according to claim 1 , wherein applying pressure from outside the distal portion of the elongate tube, such as to cause the inner lining and the distal portion of the elongate tube to become coupled to the frame comprises coupling the inner lining to an inner surface of the cylindrical portion of the frame, such that the inner lining forms a substantially cylindrical tube.
8. The method according to claim 7 , wherein the struts within the cylindrical portion of the frame are shaped to define cells, and a width of each of the cells as measured around a circumference of the cylindrical portion is less than 2 mm.
9. The method according to claim 1 , wherein placing the distal portion of the elongate tube around at least a portion of the frame comprises placing the distal portion of the elongate tube around only a portion of the cylindrical portion of the frame, such the distal portion of the elongate tube does not overlap with the entire inner lining.
10. The method according to claim 9 , wherein placing the distal portion of the elongate tube around only a portion of the cylindrical portion of the frame comprises preventing radial expansion of the portion of the cylindrical portion of the frame around which the distal portion of the elongate tube is placed, thereby causing the portion of the cylindrical portion of the frame around which the distal portion of the elongate tube is placed to be narrower than a portion of the cylindrical portion of the frame around which the elongate tube is not placed.