Pumps – Expansible chamber type – Inlet and discharge distributors at opposite ends of tubular...
Reexamination Certificate
2000-12-22
2002-10-15
Freay, Charles G. (Department: 3746)
Pumps
Expansible chamber type
Inlet and discharge distributors at opposite ends of tubular...
C417S392000, C417S394000, C604S153000, C210S321780, C210S323200
Reexamination Certificate
active
06464476
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to pumps, and more particularly to improvements in reciprocating linear pumps. The linear pump of the present invention is relatively simple and thus inexpensive to manufacture and maintain, yet has a surprisingly high pump efficiency. The pump of the present invention is particularly well suited for pumping blood intracorporeal or extra-corporeal bridge to a transplant or a total cardiac replacement. The pump may alternatively be used to pump sewage or wastewater, or may be used in other industrial, commercial, medical, astronautical, aeronautical, or military applications.
BACKGROUND OF THE INVENTION
Pumps have been used for centuries, and various types of pumps have been devised, including positive displacement pumps, rotary pumps, vane pumps, and centrifugal pumps. While many of these pumps are well suited for particular uses, pumps in general do not have a high efficiency, and are not well suited for special applications, such as pumping blood or pumping sewage wastewater.
Current pumps include the crew of Archimedes that interferes with axial blood flow. Many pumps cause damage to the blood components as these blood components make either direct or near contact that surfaces of the pump. Ventricular assist pumps currently employ mechanisms to move blood that stresses the blood in some situations and are non-pulsatile.
When pumping blood, constant flow by conventional pumps may cause “pumphead” because of the sustained vasiodilation. The alterations in the cellular components of the blood, typical with rotary and constant flow pumps, may be due to reactions with the vasodialted capillaries and the components of the blood reacting to this abnormal state. Ischemia may be present to the decreased lumen secondary to an accumulation of platelets and/or the blood not pulsing enough to create turbulence and transfer the gases and nutrients. This would thus be analogous to going too fast by a road sign. It may be due to the hemodynamics of fluid flow with a non-newtonian fluid. The pulse flow preferably allows for a psychological pause in the short duration dilated phase and the contraction may facilitate the movement of the blood components.
Various types of linear pumps have been devised, including linear pumps particularly intended for pumping blood. U.S. Pat. Nos. 5,676,162 and 5,879,375 disclose reciprocating pump and linear motor arrangements for pumping blood. The assembly includes a piston-valve which is placed at the inlet end of a hollow chamber. The valve leaflets may be in any arbitrary position. The pump module arrangement may occupy a space of no more than approximately 6 cm. in diameter and 7.5 cm. long. In a preferred embodiment, a quick connect locking system may be utilized, as shown in FIG. 3 of the '162 Patent. FIG. 11 of the '375 Patent illustrates the anatomical arrangement of a surgically implantable pump with a reciprocating piston-valve. Other patents directed to implantable pumps and or linear pumps include U.S. Pat. Nos. 5,676,651, 5,693,091, 5,722,930, and 5,758,666.
Conventional pumps have long been used to pump a slurry consisting of a fluid and a semi-solid material, which is common in sewage wastewater. Conventional wastewater pumps have significant problems due to pump plugging and abrasion, which increases repair and maintenance costs, and results in poor pump efficiency and/or short pump life.
The disadvantages of the prior art are either overcome or are reduced by the present invention, and improved linear pumps and methods of pumping fluids are hereinafter disclosed which overcome many of the disadvantages of prior art pumps, including relatively high cost of manufacture and/or poor pump efficiency.
SUMMARY OF THE INVENTION
The present invention is directed to highly versatile linear pumps. In one embodiment the pump may be used for pumping blood through a living body, and it may include a pump housing having a non-oxygenated blood inlet, a non-oxygenated blood outlet, an oxygenated blood inlet, and an oxygenated blood outlet. The pump may include both a non-oxygenated bladder and an oxygenated bladder each for receiving and for outputting blood at a desired pulse rate. The pump may further include a non-oxygenated blood inlet check valve, a non-oxygenated outlet check valve, an oxygenated blood inlet check valve, and an oxygenated blood outlet check valve for passing the blood through the pump. An inlet plate and an outlet plate may be secured to corresponding ends of each of the two bladders. The pump includes a prime mover for linearly moving an inlet plate secured to a respective bladder with respect to an outlet plate secured to the same bladder such that linear movement of the inlet plate with respect to the outlet plate alters the volume within the bladder to pump the blood. A control member is provided for controlling linear movement of the end plates and thereby controlling the first pulse rate and the second pulse rate caused by the pumping action of the first bladder and the second bladder, respectively. The pump flow for the decreased demand of the right ventricle may be accommodated by pump size, output, bladder size, or stroke volume.
The pump may be used extra-corporeal as a single unit to move blood through the inner chamber and a lubricant/thermal fluid through the outer chamber to maintain a comfortable state for the patient treated. The fluid that is passed through the outer chamber may be such to facilitate components to be moved through a selectively permeable inner bladder. This use is in a dialysis-like setting. Another embodiment only utilizes the inner chamber for fluid movement to realize the benefit of the parastalyic movement.
In still another embodiment, the pump may assist the heart as a left ventricular assist device with configuration and attachment such as is found in the Heart Mate II LVAS. In yet another embodiment, the pump is used as a wastewater pump and includes a housing having a throughbore about a central axis, an incoming end cap and outflowing end cap, a flexible generally tubular bladder defining an inner chamber and an outer chamber, an incoming inner chamber check valve, an outflowing inner chamber check valve, at least one incoming outer chamber check valve, at least one outflowing outer chamber check valve, and a power supply with electronics for controlling the attraction and repulsion of the end caps to cyclically move one end cap with respect to the other end cap along a central axis in a manner which cyclically varies the volume of both the inner chamber and the outer chamber, thereby creating propulsion forces and pumping the wastewater.
The pump according to the present invention may utilize magnetic propulsion and contraction forces to change the length and thus the internal volume within a flexible bladder, which may be reinforced with a weave comprising fibrous reinforcing members. In an alternate embodiment, hydraulic power to cylinders is controlled to effect movement of the end caps and thereby cyclically change the volume of the inner chamber and the outer chamber which are separated by the bladder. Volume changes within the bladder and in many applications between the bladder and the external housing may be used to generate the pumping forces.
To create compressive forces to move fluid, the pump may utilize one or more inner chambers and corresponding outer chambers which may each contribute to the pumping of fluid. The pump according to the present invention thus may fill an outer chamber with fluid as the inner chamber is venting, then fill the inner chamber with fluid while the outer chamber is venting. This feature minimizes the pressure differential, which decreases the work and thus the effort needed for the pump.
In one embodiment, the pump is used as a blood pump and two bladders are provided, preferably with counter offset check valves to ideally balance the pump operation with due concern to output demands. For this embodiment, the chamber exterior of the bladders may be vented to atmosphere, or alternatively
Guagliano Peter A.
Ross Anthony C.
Browning & Bushman P.C.
Solak Timothy P.
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