Hemodialysis apparatus with degassing means for the dialysis solution

• US 4,770,769 A
• Filed: 07/16/1985
• Issued: 09/13/1988
• Est. Priority Date: 09/02/1978
• Status: Expired due to Fees

• Current Assignee: Fresenius AG (Fresenius SE & Co. KGaA)
• Original Assignee: Fresenius AG (Fresenius SE & Co. KGaA)
• Inventors: Schael, Wilfried
• Primary Examiner(s): Richman, Barry S.
• Assistant Examiner(s): Jordan, Richard D.
• Application Number:
  US06/755,772
• Time in Patent Office: 1,155 Days
• Field of Search: 210/96.2, 210/97, 210/104, 210/109, 210/137, 210/149, 210/181, 210/188, 210/195.2, 210/257.2, 210/258, 210/321, 210/416, 210/433.2, 210/927, 210/929, 210/175
• US Class Current: 210/96.2
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1607 before use, i.e. upstream of dialyser
• CPC Class Codes: A61M 1/1609 after use, i.e. downstream of dialyser
• CPC Class Codes: A61M 1/1639 linked by membranes
• CPC Class Codes: A61M 1/1692 Detection of blood traces in dialysate
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3379 Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/705 Testing of filters for leaks
• CPC Class Codes: Y10S 210/929 Hemoultrafiltrate volume measurement or control processes

Abstract

The ultra-filtration in a hemodialysis operation is controlled by a control apparatus which is connected to a balancing device (1) and to a dosing device (9) to form a closed loop control circuit for the metered supply of dialysis concentrate into the balancing device and for the metered supply of fresh dialysis solution into the dialyzer. The closed loop control circuit controls the alternating supply of fresh dialysis solution into one chamber of a balancing device and the withdrawal of used-up dialysis solution from the other chamber of the balancing device. The closed loop control circuit also controls a pump for the metered withdrawal of used-up dialysis solution out of the dialysis circulatory system. The dosing device operates as a proportionality device to produce fresh dialysis solution from water and dialysis concentrate whereby the concentrate is dosed and the dialysis solution is also dosed or metered.

Claims

1. A hemodialysis apparatus, comprising dialyzer means (4, 5), fresh dialysis solution supply means (50, 51, 52, 53, 54) and used dialysis solution discharge means (57, 85), said dialyzer means (4, 5) including a dialyzer housing (4) and a semi-permeable membrane (5) dividing said dialyzer housing into a dialyzing chamber means and into blood chamber means connectable to a patient, said dialyzing chamber means having an inlet and an outlet, first conduit means connected at one end thereof to said blood chamber means and connectable at another end thereof to a patient, second conduit means connected to said inlet and outlet of dialyzing chamber means, to said fresh dialysis solution supply means, and to said used dialysis solution discharge means for providing a flow circuit therebetween, said fresh dialysis solution supply means comprising two balancing chambers (22, 23), a movable element (24, 25) in each of said two balancing chambers (22, 23) for dividing each of said balancing chambers into two balancing spaces (22a, 22b and 23a, 23b) thereby providing a total of four balancing spaces, a first set of controllable valve means (14, 17, 18, 21) in said second conduit means for alternately connecting one balancing space (22a or 23a) of a first group of two (22a, 23a) of said four balancing spaces to said inIet of said dialying chamber means and to said fresh dialysis solution supply means to alternately supply fresh dialysis solution into said dialyzing chamber means from said fresh dialysis solution supply means through said first group of two balancing spaces, a second set of controllable valve means (15, 16, 19, 20) in said second conduit means for alternately connecting one balancing space (22b or 23b) of a second group of two (22b, 23b) of said four balancing spaces to said outlet of said dialyzing chamber means and to said used dialysis solution discharge means to alternately discharge used dialysis solution from said dialyzing chamber means into said used dialysis solution discharge means through said second group of two balancing spaces, said second conduit means forming a closed dialysis solution circulating circuit between said dialyzing chamber means and the respective one of said balancing chambers, means connected to said closed dialysis solution circuilating circuit for removing a determined quantity of ultrafiltrate from said closed dialysis solution circulating circuit, first degassing means (56) connected to said fresh dialysis solution supply means and to said first group of two balancing spaces for supplying degassed fresh dialysis solution into said first group of two balancing spaces, second degassing means connected to said outlet of said dialyzing chamber means and to said second group of two balancing spaces for supplying degassed used dialysis solution into said second group of two balancing spaces, whereby always fresh degassed dialysis solution is balanced against used degassed dialysis solution, pump means operatively connected to said second conduit means for crculating dialysis solution in said closed dialysis solution circulating circuit, and control means operatively connected to said first and second sets of controllable valve means for operating said first and second sets of controllable valve means so that one balancing space of said first group of balancing spaces reoeives fesh dialysis solution while the other balancing space of said first group of balancing spaces supplies fresh dialysis solution into said dialyzing chamber means, and so that one balancing space of said second group of balancing spaces discharges used dialysis solution while the other balancing space receives used dialysis solution, whereby one balancing chamber is being filled with fresh dialysis solution, thereby discharging used dialysis solution while the other balancing chamber is being filled with used dialysis solution from said dialyzing chamber means, thereby discharging fresh dialysis solution into said dialyzing chamber means and vice versa, wherein said pump means include a variable capacity pump and a pump motor for driving said variable capacity pump, and wherein said control means for said first and second sets of controllable valve means operate said first and second sets of controllable valve means so that the charging of fresh dialysis solution into one balancing chamber presently disconnected from said inlet of said dialyzing chamber means, is already completed when a supply of fresh dialysis solution from the other balancing chamber into the dializing chamber means becomes exhausted.

2. The apparatus of claim 1, wherein said control means for said first and second sets of controllable valve means comprise sensor means operatively arranged for sensing end positions of said movable elements to thereby switch-over said sets of controllable valve means in response to said movable elements reaching a respective end position, whereby a switch-over signal is derived from that balancing chamber which is presently connected to said closed dialysis solution circulating circuit.

3. The apparatus of claim 2, wherein said fresh dialysis soluion supply means comprise mixing means connected to a source of water and to a source of dialysis concentrate, and dosing means connected to said mixing means for supplying said dialysis concentrate to said mixing means, said control means being also connected to said dosing means for controlling the dosing means also in response to said movable elements reaching an end position, whereby a dosing operation is cased for each switch over of said first and second sets of controllable valve means.

4. The apparatus of claim 1, further comprising means for monitoring a concentration of said fresh dialysis solution flowing to said inlet of said dialyzing chamber means.

5. The apparatus of claim 1, further comprising third conduit means (68) operatively interconnecting said first and second degassing means, further valve means (48) in said third conduit means, operating means connected to said further valve means, fluid level sensor means (49) in said second degassing means (47) for said used dialysis solution, connected to said operating means of said further valve means (48) for operating said further valve means (48) in response to a fluid level in said second degassing means (47).

6. The apparatus of claim 1, comprising further valve means (48) operatively connected to said second degassing means for venting said second degassing means (47).

7. The apparatus of claim 6, further comprisign a level sensor (49) in said second degassing means (47) for sensing a liquid level in said second degassing means and for operating said further valve means in response to a certain liquid level in said second dagassing means.

8. The apparatus of claim 1, further comprising a bypass conduit (83) connected to said second degassing means, volumetric pump means (7) having an inlet connected to said bypass conduit and a pump outlet, ultra-filtrate sample conduit means (85) connected to said pump outlet for gathering liquid withdrawn from said second degassing means into a measuring container.

9. A hemodialysis apparatus, comprising dialyzer means (4, 5), fresh dialysis solution supply means (50, 51, 52, 53, 54) and used dialysis solution discharge means (57, 85), said dialyzer means (4, 5) including a dialyzer housing (4) and a semi-permeable membrane (5) dividing said dialyzer housing into a dialyzing chamber means and into blood chamber means connectable to a patient, said dialyzing chamber means having an inlet and an outlet, first conduit means connected at one end thereof to said blood chamber means and connectable at another end thereof to a patient, second conduit means connected to said inlet and outlet of said dialyzing chamber means, to said fresh dialysis solution supply means, and to said used dialysis solution discharge means for providing a flow circuit therebetween, said fresh dialysis solution supply means comprising two balancing chambers (22, 23), a movable element (24, 25) in each of said two balancing chambers (22, 23) for dividing each of said balancing chambers into two balancing spaces (22a, 22b and 23a, 23b) thereby providing a total of four balancing spaces, a first set of controllable valve means (14, 17, 18, 21) in said second conduit means for alternately connecting one balancing space (22a or 23a) of a first group of two (22a, 23a) of said four balancing spaces to said inlet of said dialyzing chamber means and to said fresh dialysis solution supply means to alternately supply fresh dialysis solution into said dialyzing chamber means from said fresh dialysis solution supply means through said first group of two balancing spaces, a second set of controllable valve means (15, 16, 19, 20) in said second conduit means for alternately connecting one balancing space (22b or 23b) of a second group of two (22b, 23b) of said four balancing spaces to said outlet of said dialyzing chamber means and to said used dialysis solution discharge means to alternately discharge used dialysis solution from said dialyzing chamber means into said used dialysis solution discharge means through said second group of two balancing spaces, said second conduit means forming a closed dialysis solution circulating circuit between said dialyzing chamber means and the respective one of said balancing chambers, ultrafiltrate pump means (7) connected to said closed dialysis solution circuilating circuit for removing a determined quantity of ultrafiltrate from said closed dialysis solution circulating circuit, first degassing means (56) connected to said fresh dialysis solution supply means and to said first group of two balancing spaces for supplying degassed fresh dialysis solution into said first group of two balancing spaces, second degassing means (47) connected to said outlet of said dialyzing chamber means and to said second group of two balancing spaces for supplying degassed used dialysis solution into said second group of two balancing spaces, whereby always fresh degassed dialysis solution is balanced against used degassed dialysis solution, circulation pump means (67) operatively connected to said second conduit means for circulating dialysis solution in said closed dialysis solution circulating circuit, and control means operatively connected to said first and second sets of controllabel valve means for operating said first and second sets of controllable valve means so that one balancing space of said first group of balancing spaces receives fresh dialysis solution while the other balancing space of said first group of balancing spaces supplies fresh dialysis solution into said dialyzing chamber means, and so that one balancing space of said second group of balancing spaces discharges used dialysis solution while the other balancing space receives used dialysis solution, whereby one balancing chamber is being filled with fresh dialysis solution, thereby discharging used dialysis solution while the other balancing chamber is being filled with used dialysis solution from said dialyzing chamber means, thereby discharging fresh dialysis solution into said dialyzing chamber and vice versa, said ultrafiltrate pump means for removing a determined quantity of ultrafiltate from said closed dialysis solution circulating circuit comprising a volumetric pump (7) delivering a precisely predetermined liquid quantity with each individual pump stroke, said ultrafiltrate pump means (7) being connected with its suction inlet to a bubble-free part of said closed dialysis solution circulating circuit, said circulation pump means (67) having a suction inlet also connected to an outlet of said second degassing means (47) for maintaining used dialysis liquid at a reduced pressure at all times to keep gasses from entering into solution in said used dialysis liquid.

10. The apparatus of claim 9, wherein said volumetric pump is a membrane pump.

11. The apparatus of claim 9, wherein said second degassing means (47) comprise an air separator chamber (47) having a dialysis liquid inlet means and dialysis liquid outlet means and an air outlet in an upper portion of said air separator chamber, means for controlling the level of dialysis liquid in said air separator chamber (47), and a degassing pump means (54) connected by a conduit (68) with said air outlet, said degassing pump means (54) providing in said air separator chamber (47) a reduced pressure which is more intensive than a reduced pressure caused by said means for removing a determined quantity of ultrafiltrate.

12. The apparatus of claim 11, wherein said means for controlling the level of dialysis liquid in said air separator chamber (47) comprise a liquid level sensor (49) and a valve (48) connected in said conduit (68) between said air outlet and said degassing pump means (54), said valve (48) being operable in response to a switching signal from said level sensor (49).

13. A homodialysis apparatus, comprising dialyzer means (4, 5), fresh dialysis solution supply means (50, 51, 52, 53, 54) and used dialysis solution discharge means (57, 85), said dialyzer means (4, 5) including a dialyzer housing (4) and a semi-permeable membrane (5) dividing said dialyzer housing into a dialyzing chamber means and into blood chamber means connectable to a patient, said dialyzing chamber means having an inlet and an outlet, first conduit means connected at one end thereof to said blood chamber means and connectable at another end thereof to a patient, second conduit means connected to said dialyzing chamber means, to said fresh dialysis solution supply means, and to said used dialysis solution discharge means for providing a flow circuit therebetween, sald fresh dialysis solution supply means comprising two balancing chambers (22, 23), a movable element (24, 25) in each of said two balancing chambers (22, 23) for dividing each of said balancing chambers into two balancing spaces (22a, 22b and 23a, 23b) thereby providing a total of four balancing spaces, a first set of controllable valve means (14, 17, 18, 21) in said second conduit means for alternately connecting one balancing space (22a or 23a) of a first group of two (22a, 23a) of said four balancing spaces to said inlet of said dialyzing chamber means and to said fresh dialysis solution supply means to alternately supply fresh dialysis solution into said dialyzing chamber means from said fresh dialysis solution supply means through said first group of two balancing spaces, a second set of controlable valve means (15, 16, 19, 20) in said second conduit means for alternately connecting one balancing space (22b or 23b) of a second group of two (22b, 23b) of said four balancing spaces to said outlet of said dialyzing chamber means and to said used dialysis solution discharge means to alternately discharge used dialysis solution from said dialyzing chamber means into said used dialysis solution discharge means through said second group of two balancing spaces, said second conduit means forming a closed dialysis solution circulating circuit between said dialyzing chamber means and the respective one of said balancing chambers, means connected to said closed dialysis solution circulating circuit for removing a determined quantity of ultrafiltrate from said closed dialysis solution circulating circuit, first degassing means (56) connected to said fresh dialysis solution supply means and to said first group of two balancing spaces for supplying degassed fresh dialysis solution into said first group of two balancing spaces, second degassing means (47) connected to said outlet of said dialyzing chamber means and to said second group of two balancing spaces for supplying degassed used dialysis solution into said second group of two balancing spaces, whereby always fresh degassed dialysis solution is balanced against used degassed dialysis solution, pump means operatively connected to said second conduit means for circulating dialysis solution in said closed dialysis solution circulating circuit, and control means operatively connected to said first and second sets of controllable valve means for operating said first and second sets of controllable valve means so that one balancing space of said first group of balancing spaces receives fresh dialysis solution while the other balancing space of said first group of balancing spaces supplies fresh dialysis solution into said dialyzing chamber means, and so that one balancing space of said second group of balancing spaces discharges used dialysis solution while the other balancing space receives used dialysis solution, whereby one balancing chamber is being filled with fresh dialysis solution, thereby discharging used dialysis solution while the other balancing chamber is being filled with used dialysis solution from said dialyzing chamber means, thereby discharging fresh dialysis solution into said dialyzing chamber and vice versa, said second degassing means (47) comprising an air separator chamber (47) having dialysis liquid inlet means and dialysis liquid outlet means and an air outlet in an upper portion of said air separator chamber, means for controlling the level of dialysis liquid in said air separator chamber (47), and a degassing pump means (54) connected by a conduit (68) with said air outlet, said degassing pump means (54) providing in said air separator chamber (47) a reduced pressure which is more intensive than a reduced pressure caused by said means for removing a determined quantity of ultrafiltrate.