Pumps – Expansible chamber type – Bellows-type chamber
Patent
1988-05-27
1990-05-15
Smith, Leonard E.
Pumps
Expansible chamber type
Bellows-type chamber
417478, 600 16, 92117R, F04B 4300
Patent
active
049253778
DESCRIPTION:
BRIEF SUMMARY
Field of Invention
The present invention relates to a pump for pumping biological fluids, in particular blood.
The pump according to the invention has primarily been developed for use as an extracorporeal blood pump in conjunction, for instance, with surgical operations, dialysis, oxygenation processes, etc. It is also conceivable, however, for a pump according to the invention to be constructed in a manner which would enable it to be implanted in a patient, as an artificial heart.
BACKGROUND OF THE INVENTION
Extracorporeal blood pumps used today in conjunction with surgical procedures, dialysis, blood oxygenation, etc. are almost exclusively in the form of peristaltic roller pumps. Peristaltic pumps when used in the present context are encumbered with a number of serious drawbacks, however. For example, when pumping blood with the aid of a roller operated peristaltic pump it is difficult to prevent damage to blood corpuscles in the pumped blood, when the hose through which the blood is conducted is subjected to the pressure of the rollers. Thus, it is difficult to avoid part of the blood corpuscles present from being crushed and destroyed as the hose is compressed by the rollers acting thereon. Even though the compression rollers do not close the hose completely, but leave a narrow through passage, the flow velocities occuring in this narrow passage are so high as to cause damage to the blood corpuscles in the blood pumped therethrough. Another serious problem is encountered with the use of such pumps when the flow of blood to the inlet side of the pump radically diminishes or ceases completely, for example as a result of a blockage at the end of the catheter connecting the pump to a blood vessel. Such blockages are liable to occur with relative ease, for example as a result of abutment of the catheter orifice with the wall of the aforesaid blood vessel. In cases such as these a peristaltic pump will continue to carry out a pumping action, and in doing so will create on the inlet side of the pump subpressures of such magnitude as to cause serious injury to the patient connected to the pump. In addition it is difficult to adapt the flow and pressure characteristics of a peristaltic pump to what can be considered suitable characteristics from a physiological aspect. The use of especially designed centrifugal pumps as extracorporeal blood pumps has also been tried to some extent. Such pumps expose the pumped blood to extremely high shear forces, which are liable to damage the blood corpuscles. In order to achieve high pressures, it is necessary to employ extremely high rotational velocities.
SUMMARY OF THE INVENTION
Consequently, the object of the present invention is to provide an improved blood pump intended primarily for extracorporeal use, but which can also conceivably be constructed as an artificial heart for implantation.
BRIEF DESCRIPTION OF DRAWING
FIG. 1: FIG. 1 is a cross-sectional view of a first embodiment of the invention.
FIG. 2: FIG. 2 is a cross-sectional view of a second embodiment of the invention.
FIG. 3: FIG. 3 is a cross-sectional view of a third embodiment of the invention.
DETAILED DESCRIPTION OF EMBODIMENTS
The pump according to the invention illustrated in FIG. 1 comprises a cylinder 1 which is made of some suitable material and has an inlet end 1a and an outlet end 1b. The cylinder 1 has a constant cross-section throughout its length. Spaced axially in the cylinder 1 are two discs or plates 2 and 3 which cover substantially the whole cross-sectional area of the cylinder. Each of the discs 2, 3 is carried by a respective spindle 4 and 5 each of which is journalled for axial movement in a respective stationary holder 6 and 7, the holders being so formed and being so arranged in the cylinder 1 as to enable the two discs to move reciprocatingly through a predetermined distance in the cylinder 1. The discs may be acted upon advantageously in one direction of movement thereof by respective springs 8 and 9, and driven in their opposite directions of movement by suitable drive
REFERENCES:
patent: 194010 (1877-08-01), Stewart
patent: 229563 (1880-07-01), Van Eps
patent: 2686006 (1954-08-01), Hasselquist
patent: 4111616 (1978-09-01), Rankin
patent: 4781716 (1988-11-01), Richelsoph
Rotellar, A Blood Pump Which Minimizes Haemolysis, Jan. 25, 1958, p. 197, The Lancel.
Derwant's abstract No. 858 816 E/26, SU H7554, 23 Jul. 1975.
Inacio Jorge
Nilsson Erling
Data Promeditech I.N.C. AB
Smith Leonard E.
Szczecina Jr. Eugene L.
LandOfFree
Pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-618704