System and method for monitoring a flow of dialysis fluid in a dialysis machine

• US 5,792,367 A
• Filed: 08/16/1996
• Issued: 08/11/1998
• Est. Priority Date: 02/18/1994
• Status: Expired due to Term

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: Gambro AB (Baxter International Inc.)
• Inventors: Wejfeldt, Gunilla, Mattisson, Leif
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US08/693,263
• Time in Patent Office: 725 Days
• Field of Search: 210/85, 210/87, 210/90, 210/143, 210/321.65, 210/433.1, 210/637, 210/646, 210/739, 210/741, 210/742, 210/929, 604/4-6, 364/500, 364/502, 364/510, 73/1.01, 73/1.16, 73/1.57, 73/38, 73/40, 73/865.9
• US Class Current: 702/100
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/1647 with flow rate measurement of the dialysis fluid, upstream and downstream of the dialyser
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: G01F 1/363 with electrical or electro-mechanical indication G01F1/37 and G01F1/38 take precedence
• CPC Class Codes: G01F 25/13 using a reference counter
• CPC Class Codes: G05D 7/0682 using a plurality of flow sources
• CPC Class Codes: Y10S 210/929 Hemoultrafiltrate volume measurement or control processes

Abstract

Apparatus for monitoring flow of a dialysis fluid through a dialyzer is disclosed including a computer for calculating the flow rate of the dialysis fluid into and out of the dialyzer based on the formula P-P_O =k*Qⁿ in which P is the pressure in the dialysis fluid between a throttle and a pump either upstream or downstream of the dialyzer, P_O is the pressure in the dialysis fluid on the opposite side of the throttles from the pump, k is a characteristic coefficient for the throttle, Q is the flow of the dialysis fluid through the throttle, and N is a characteristic exponent for the throttle, and the apparatus includes microprocessor for calculating the values of k and P_O prior to use and for calculating the value of P_O during use of the dialyzer. Methods for carrying out such monitoring are also disclosed.

Claims