BALANCED FLOW DIALYSIS MACHINE
First Claim
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1. A dialysis cassette for a renal therapy machine, the cassette comprising:
- a housing configured and arranged to be placed in the machine;
a flexible membrane attached to the housing, the membrane and housing cooperating with the machine to perform a valving function controlling flow of a renal failure therapy fluid;
fluid pathways within the housing for routing the renal failure therapy fluid; and
at least one balancing system and at least four valves operably connected to the at least one balancing system, the balancing system operably connected to the fluid pathways and to pumps for pumping the renal failure therapy fluid, the at least one balancing system configured to equalize the flow of the renal failure therapy fluid to and from a dialyzer or a patient,wherein the cassette and the at least one balancing system are responsive to at least one pressure sensor for sensing a pressure of the renal failure therapy fluid and conveying a signal representative of the pressure to a controller of the machine, wherein the controller and the signal are configured to control the valves for a flow of renal failure therapy fluid to and from the at least one balancing system so that a pressure of the fresh renal failure therapy fluid to the at least one balancing system is equal to a pressure of spent renal failure therapy fluid to the at least one balancing system.
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Accused Products
Abstract
A system and method for balancing flows of renal replacement fluid is disclosed. The method uses pressure controls and pressure sensing devices to more precisely meter and balance the flow of fresh dialysate and spent dialysate. The balancing system may use one or two balancing devices, such as a balance tube, a tortuous path, or a balance chamber.
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Citations
25 Claims
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1. A dialysis cassette for a renal therapy machine, the cassette comprising:
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a housing configured and arranged to be placed in the machine; a flexible membrane attached to the housing, the membrane and housing cooperating with the machine to perform a valving function controlling flow of a renal failure therapy fluid; fluid pathways within the housing for routing the renal failure therapy fluid; and at least one balancing system and at least four valves operably connected to the at least one balancing system, the balancing system operably connected to the fluid pathways and to pumps for pumping the renal failure therapy fluid, the at least one balancing system configured to equalize the flow of the renal failure therapy fluid to and from a dialyzer or a patient, wherein the cassette and the at least one balancing system are responsive to at least one pressure sensor for sensing a pressure of the renal failure therapy fluid and conveying a signal representative of the pressure to a controller of the machine, wherein the controller and the signal are configured to control the valves for a flow of renal failure therapy fluid to and from the at least one balancing system so that a pressure of the fresh renal failure therapy fluid to the at least one balancing system is equal to a pressure of spent renal failure therapy fluid to the at least one balancing system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A dialysis cassette for a renal therapy machine, the cassette comprising:
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a housing for the cassette configured and arranged to be placed in the machine; a flexible membrane attached to the housing, the membrane and housing cooperating with a controller of the machine to operate valves controlling a flow of a renal failure therapy fluid; fluid pathways within the housing for routing the renal failure therapy fluid; at least one balancing system operably connected to the fluid pathways, and at least four valves operably connected to the at least one balancing system, wherein the at least one balancing system is configured to equalize the flow of the renal failure therapy fluid to and from a dialyzer or a patient, and optionally, a temperature sensor for sensing a temperature of the renal failure therapy fluid within the at least one balancing system; and a separator in the at least one balancing system, the separator configured to move freely within the balancing system, wherein the controller is configured to control the valves for the flow of the renal failure therapy fluid to and from the at least one balancing system so that a pressure of the fresh renal failure therapy fluid to the at least one balancing system is equal to a pressure of spent renal failure therapy fluid to the at least one balancing system. - View Dependent Claims (12, 13, 14)
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15. A method of equalizing fluid flow in a dialysis cassette for a renal therapy machine, the method comprising:
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providing a renal failure therapy machine with a controller and a dialysis cassette therefor, the cassette and the controller configured for equalizing flow of fresh and spent dialysis fluid; sequentially pumping the fresh and spent dialysis fluid into at least one balancing system of the cassette; optionally, selecting an operating pressure for the at least one balancing system; and controlling a flow of the fresh and spent dialysis fluid into the at least one balancing system so that a pressure of the fresh dialysis fluid in the at least one balancing system when the at least one balancing system is filled with fresh dialysis fluid equals a pressure of the spent dialysis fluid in the at least one balancing system when the at least one balancing system is filled with spent dialysis fluid, and if an operating pressure has been selected, wherein the pressures in the at least one balancing system equal the operating pressure. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method of equalizing fluid flow in a dialysis cassette for a renal therapy machine, the method comprising:
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providing a renal failure therapy machine with a controller and a dialysis cassette therefor, the cassette and the controller configured for equalizing flows of fresh and spent dialysis fluid; sequentially pumping the fresh and spent dialysis fluid into at least one balancing system of the cassette, the at least one balancing system operably connected to at least four valves for inflow and outflow of dialysis fluid; sensing a pressure of the fresh dialysis fluid and the spent dialysis fluid in the at least one balancing system; and controlling a flow of the fresh and spent dialysis fluid into the at least one balancing system so that a pressure of the fresh dialysis fluid in the at least one balancing system when the at least one balancing system is filled with fresh dialysis fluid equals a pressure of the spent dialysis fluid in the at least one balancing system when the at least one balancing system is filled with spent dialysis fluid. - View Dependent Claims (22, 23, 24, 25)
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Specification