Apparatus for pumping a fluid

Claim 2

A blood pump comprising: a plurality of flexible vessels to contain blood; a plurality of rigid containers each enclosing a respective one of said vessels, said vessels and containers being transparent so as to allow visual monitoring of the blood in the vessels; actuator means to apply and withdraw a working fluid to and from each of said containers to respectively collapse and distend said vessels, said actuator means providing a pressure of working fluid such that the pressure of the pumped blood is of a similar order to human blood pressure; a plurality of blood flow conduits having a common inlet and a common outlet and connections therebetween with an opening disposed at the base of each of said vessels and above at least one of the common inlet and common outlet so as to avoid the formation of stagnant areas in the vessels and prevent transfer of air to the outlet; a plurality of valves respectively associated with said vessels forming part of said connections and each having two states to respectively communicate the associated vessel with said inlet and said outlet when such vessel is distended and collapsed; sensor means to detect the amount of blood in at least one of said vessels; and control means responsive to said sensor means to control said actuator means and said valve states in predetermined phase sequence to effect substantially continuous pumping between said common inlet and outlet.

Claim 3

Apparatus according to claim 1, comprising a plurality of weight-sensing devices, each one coupled with a respectively different one of said vessels, each operable to switch said control means from one phase to another in said sequence in response to a predetermined weight of fluid in the respective vessel.

Claim 4

A blood pump for extra corporeal circulation of blood, comprising: a plurality of rigid fluid-tight cylinders; a flexible fluid-tight container received in each cylinder; a plurality of first conduits, each communicating through each respective cylinder with the inside of the flexible container received in such cylinder; a plurality of second conduits, each communicating through each respective cylinder with the exterior of the flexible container received in such cylinder; pump means communicating with each of the second conduits for selectively pressurizing and partially evacuating the region within the respective cylinders, exteriorly of the flexible containers received in such cylinders; a blood inlet conduit for receiving blood flowing extra-corporeally; a valve block; all of said first conduits, said blood inlet conduit and said blood outlet conduit being connected to the valve block; first check valve means in the valve block for selectively automatically communicating the blood inlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing partial evacuation induced by said pump means and for stopping communication of the blood inlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing pressurization induced by said pump means; second check valve means in the valve block for selectively automatically communicating the blood outlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing pressurization induced by said pump means and for stopping communication of the blood outlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing partial evacuation induced by said pump means; means for sensing the amount of blood in each flexible container; control means controlling said pump means to alternately pressurize and partially evacuate said regions within the respective cylinders, through the respective second conduits; and signalling means functionally interconnecting the sensing means with the control means for signalling the control means to a. partially evacuate said region within each respective cylinder whose flexible container does not yet contain a first, predetermined, larger amount of blood until such first, predetermined amount is contained in such flexible container, and then to b. pressurize said region within each respective cylinder whose flexible container contains in excess of a second, predetermined, smaller amount of blood until such second, predetermined amount is contained in such flexible container; and means for staggering the operation of said pump means to generally continuously provide filling of at least one said flexible container and emptying of at least another said flexible container; the means for sensing the amount of blood in each flexible container being constituted by: a fixed support; means independently securing each cylinder, for support, to the fixed support and being configured to provide for limited movement of the respective cylinders vertically toward and away from the fixed support; spring means associated between each cylinder and the fixed support for permitting gravity induced vertical movement of each respective cylinder in one sense when the flexible container received therein is one being filled with and emptied of blood and for permitting spring restoration force-induced vertical movement of each respective cylinder in the opposite sense when the flexible container received therein is being the other of emptied of and filled with blood; first sensing means for each respective cylinder mounted to move therewith; and second stationarily-mounted sensing means for each respective cylinder, respective of said first and second sensing means being juxtaposed to activate said signalling means when the respective first and second sensing means become collocated.

Claim 5

A blood pump for extra corporeal circulation of blood, comprising: a plurality of rigid fluid-tight cylinders; a flexible fluid-tight container received in each cylinder; a plurality of first conduits, each communicating through each respective cylinder with the inside of the flexible container received in such cylinder; a plurality of second conduits, each communicating through each respective cylinder with the exterior of the flexible container received in such cylinder; pump means communicating with each of the second conduits for selectively pressurizing and partially evacuating the region within the respective cylinders, exteriorly of the flexible containers received in such cylinders; a blood inlet conduit for receiving blood flowing extra-corporeally; a valve block; all of said first conduits, said blood inlet conduit and said blood outlet conduit being connected to the valve block; first check valve means in the valve block for selectively automatically communicating the blood inlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing partial evacuation induced by said pump means and for stopping communication of the blood inlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing pressurization induced by said pump means; second check valve means in the valve block for selectively automatically communicating the blood outlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing pressurization induced by said pump means and for stopping communication of the blood outlet conduit with such of said first conduits as serve a said flexible container received in a said cylinder undergoing partial evacuation induced by said pump means; means for sensing the amount of blood in each flexible container; control means controlling said pump means to alternately pressurize and partially evacuate said regions within the respective cylinders, through the respective second conduits; and signalling means functionally interconnecting the sensing means with the control means for signalling the control means to a. partially evacuate said region within each respective cylinder whose flexible container does not yet contain a first, predetermined, larger amount of blood until such first, predetermined amount is contained in such flexible container, and then to b. pressurize said region within each respective cylinder whose flexible container contains in excess of a second, predetermined, smaller amount of blood until such second, predetermined amount is contained in such flexible container; and means for staggering the operation of said pump means to generally continuously provide filling of at least one said flexible container and emptying of at least another said flexible container; the means for sensing the amount of blood in each flexible container being constituted by: a fixed support; means independently securing each cylinder, for support, to the fixed support and being configured to provide for limited movement of the respective cylinders vertically toward and away from the fixed support; spring means associated between each cylinder and the fixed support for permitting gravity induced vertical movement of each respective cylinder in one sense when the flexible container received therein is one being filled with and emptied of blood and for permitting spring restoration force-induced vertical movement of each respective cylinder in the opposite sense when the flexible container received therein is being the other of emptied of and filled with blood; first sensing means for each respective cylinder mounted to move therewith; and second stationarily-mounted sensing means for each respective cylinder, respective of said first and second sensing means being juxtaposed to activate said signalling means when the respective first and second sensing means become collocated.

Claim 6

The blood pump of claim 2 wherein the flexible containers are constituted by synthetic plastic film bags.

Claim 7

The blood pump of claim 2 wherein the connection of the blood outlet conduit to the valve block lies below all the cylinders, and the first conduits connect with the respective flexible containers at the lower extents thereof to reduce the possibility of transferring air from within the flexible containers to the blood outlet conduit.