Dry chemical mix system for hemodialysis

• US 4,812,239 A
• Filed: 05/15/1987
• Issued: 03/14/1989
• Est. Priority Date: 05/15/1987
• Status: Expired due to Term

• Current Assignee: Baxter International Inc.
• Original Assignee: CD Medical Incorporated (Baxter International Inc.)
• Inventors: Willock, Charles B., Mills, Gary N.
• Primary Examiner(s): SPEAR JR, FRANK
• Application Number:
  US07/051,054
• Time in Patent Office: 669 Days
• Field of Search: 366/279, 366/343, 366/328, 366/21, 366/28, 210/169, 210/647, 210/34.3, 210/96.2, 210/34.1, 422/265, 422/279, 422/269
• US Class Current: 210/647
• CPC Class Codes: A61M 1/1656 Apparatus for preparing dialysates
• CPC Class Codes: A61M 1/1657 with centralised supply of dialysate or constituent thereof for more than one dialysis unit
• CPC Class Codes: A61M 1/1666 by dissolving solids
• CPC Class Codes: B01F 21/10 using driven stirrers
• CPC Class Codes: B01F 35/20 Measuring; Control or regulation
• CPC Class Codes: B01F 35/21 Measuring
• CPC Class Codes: B01F 35/71705 using belts
• CPC Class Codes: B01F 35/7176 using pumps

Abstract

An apparatus for preparing dialysate solution directly from a dry chemical mix for continuous supply to a dialysis machine is disclosed. The preferred embodiment includes a drum for containing the dry chemical mix, a conveyor belt, a mixing vessel and monitoring equipment. The drum includes internal baffles that cause the dry chemical to be deposited onto the end of the conveyor belt as the drum rotates. The conveyor belt passes the chemical through a profile-determining gate and into the top of a funnel-shaped mixing vessel. The rate at which the conveyor belt delivers the chemical to the mixing vessel is governed by an electronic circuit that measures the conductivity of the dissolved solution and adjusts the belt speed as necessary to maintain the conductivity at a set value. The dissolved solution flows out the side of the mixing vessel and into a flow controller which regulates the rate at which dialysate can be withdrawn.

Claims

1. A method for providing dialysate solution to a hemodialysis apparatus comprising the steps:

introducing a dry chemical dialysate mix to a dissolution vessel at a substantially constant rate;

introducing a fluid to the dissolution vessel at a substantially constant rate;

facilitating the dissolution of the dry chemical dialysate mix into the fluid in the dissolution vessel;

detecting a physical characteristic of the dissolved solution and producing an output signal corresponding thereto;

providing a reference signal corresponding to a desired value of the physical characteristic;

comparing the output signal with the reference signal and producing a control signal corresponding thereto;

adjusting the rate at which the dry chemical dialysate mix or the fluid is introduced to the dissolution vessel in response to said control signal so as to regulate the detected physical characteristic of the dissolved solution substantially to the desired value; and

continuously removing dissolved solution for supply to the hemodialysis apparatus.

2. The method of claim 1 which further comprises the steps:

continuously depositing dry chemical dialysate mix onto the surface of a fluid in a wider upper portion of a tapered dissolution vessel; and

continuously introducing fluid through a fluid introduction port in a narrow lower portion of said tapered dissolution vessel.

3. An apparatus for the on-line preparation of dialysate solution used in hemodialysis therapy directly from a dry dialysate chemical mix comprising:

supply means for containing the dry dialysate chemical mix;

a dissolution vessel;

means for conveying dry dialysate chemical mix from the supply means to the dissolution vessel at a substantially constant rate;

means for providing dissolution liquid to the dissolution vessel at a substantially constant rate; and

means for withdrawing dissolved dialysate solution from the dissolution vessel at a substantially constant rate and for making said solution available to a dialysis machine.

4. The apparatus of claim 3 which further comprises means for agitating the dry dialysate chemical mix contained with the supply means to prevent said mix from caking.

5. The apparatus of claim 3 which further comprises means for varying the rate at which either the dry dialysate chemical mix or the dissolution liquid is provided to the dissolution vessel so as to maintain the concentration of the resulting dialysate solution at a substantially constant value.