Water pressure regulator for hemodialysis apparatus

• US 4,828,693 A
• Filed: 09/22/1987
• Issued: 05/09/1989
• Est. Priority Date: 09/22/1987
• Status: Expired due to Term

• Current Assignee: Baxter Travenol Laboratories Incorporated Deerfield IL
• Original Assignee: Baxter Travenol Laboratories Incorporated (Baxter International Inc.)
• Inventors: Cameron, Norman F., Lindsay, Edward R., Aid, James D.
• Primary Examiner(s): Therkorn, Ernest G.
• Assistant Examiner(s): Lee, Coreen Y.
• Application Number:
  US07/099,545
• Time in Patent Office: 595 Days
• Field of Search: 210/90, 210/134, 210/321.71, 210/637, 210/646, 210/137, 210/188, 210/195.2
• US Class Current: 210/137
• CPC Class Codes: A61M 1/1658 Degasification
• CPC Class Codes: A61M 1/1662 with heat exchange between fresh and used dialysate

Abstract

A pressure regulating system for a hemodialysis machine utilizes a deaeration pump and a regulator in a deaeration loop for minimizing pressure and flow transients in a heated water supply. The deaeration loop has the pump, a deaeration pressure regulator, a deaerator, and a back pressure regulator. The pump produces a negative pressure in heated water entering the deaeration pressure regulator to circulate the water in the deaeration loop and to enhance removal of air from the water. The back pressure regulator controls the loop water pressure to a value greater than the incoming water pressure and supplies water to the dialyzer system of the machine isolated from supply water pressure and flow variations.

Claims

1. In a hemodialysis apparatus having means for supplying heated water under pressure in which said water is subject to pressure and flow transients, a deaeration and pressure regulating system isolated from said pressure transients, comprising:

(a) deaeration pressure regulating means connected to receive said heated water for regulating a negative pressure of said heated water;

(b) deaeration means having an input connected to said deaeration pressure regulator to receive said heated water under negative pressure for removing air therefrom, and an outlet for deaerated water;

(c) pump means, having an input connected to said outlet to receive deaerated water from said deaeration means, for producing said negative pressure; and

(d) back pressure regulating means having

(i) a housing having an inlet connected to said output of said pump means, an outlet connected to said deaeration pressure regulating means, and an outlet connected to supply a flow of said heated deaerated water to said hemodialysis apparatus at a first flow rate,

(ii) a valve seat and valve, said valve operatively connected to a diaphragm in said housing; and

(iii) biasing and adjustment means operatively connected to said diaphragm for adjusting said pressure of said circulating heated water, said back pressure regulating means connected to an output of said pump means and to said deaeration pressure regulating means, whereby said deaeration pressure regulator means, said deaeration means, said pump means and said back pressure means form a deaeration loop, said back pressure means for controlling the pressure of said heated water circulating in said deaeration loop independently of the regulated pressure of said water from said source, said back pressure regulating means having an output for providing said hemodialysis apparatus with heated deaerated water at a constant pressure.

2. The apparatus as recited in claim 1 in which said deaeration pressure regulating means includes:

a first chamber having a first input connected to said heated water supplying means and a second input connected to said back pressure regulating means;

a second chamber adjacent said first chamber having an output connected to said input of said deaeration means; and

a pressure regulating valve disposed between said first and second chambers, said valve biased to a closed position when said deaeration pump is nonoperative and to an open position responsive to said negative pressure.

3. The apparatus as recited in claim 2 in which said first and second chambers include a bleed orifice therebetween.

4. The apparatus as recited in claim 1 in which said deaeration pressure regulating means includes:

a first chamber having an input connected to said heated water supplying means;

a second chamber adjacent said first chamber having an output connected to said input of said deaeration means and an input connected to said back pressure regulating means; and

a pressure regulating valve disposed between said first and second chambers, said valve biased to a closed position when said deaeration pump is nonoperative and to an open position responsive to said negative pressure.

5. The apparatus as recited in claim 1 in which said pump means is a positive displacement gear pump.

6. The apparatus as recited in claim 1 which further includes:

a flow restrictor disposed between said housing inlet and said pump output;

a rinse line connected across said flow restrictor to form a flow of heated deaerated water at a second flow rate much smaller than said first flow rate around said restrictor; and

at least one rinse port connected to said rinse line.