Load suspension and weighing system for a dialysis machine reservoir

Patent metadata

Field	Value
Publication number	US-9841310-B2
Application number	US-201514848012-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Dec 24, 2012
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

A load suspension and weighing system for a removable reservoir unit of a portable dialysis machine includes a centrally located flexure assembly. The flexure assembly includes magnets and a number of flexure rings which allow for movement of the magnets about a fixed circuit board. Sensors in the circuit board sense changes in the magnetic field as the magnets move in relation to the circuit board. The magnetic field changes produce a voltage output which is used by a processor to generate weight calculations. The top of the flexure assembly is attached to the interior of the dialysis machine. The entirety of the reservoir unit is suspended by a first internal frame that is attached to the bottom of the flexure assembly. Having a single flexure assembly positioned above the reservoir unit provides more accurate weight measurements while also preventing damage to the assembly from water spillage.

First claim

We claim:

1. A suspension system for suspending a load applied by a reservoir inside a dialysis machine, said system comprising:
said reservoir configured to be in fluid communication with the dialysis machine;
a frame having a first plurality of members, said frame defining a structure around which a portion of said dialysis machine is formed;
a top member attached to at least one of said first plurality of members by a first connector;
a bottom member attached to a second plurality of members by a second connector, the second plurality of members being configured to suspend the reservoir; and
a circuit board positioned between said top member and said bottom member;
wherein said top member, bottom member, and circuit board are configured to attach to said frame such that, when the reservoir is placed on the bottom member, the load translates through said bottom member and top member directly to said frame without placing said load on said circuit board.

2. The system of claim 1 , wherein said top member further comprises a first plurality of magnets and said bottom member further comprises a second plurality of magnets, wherein said first and second plurality of magnets generate a magnetic field within said system.

3. The system of claim 2 , wherein said circuit board further comprises a plurality of sensors configured to output a voltage based on sensed displacement of said magnetic field about said circuit board when the load is applied by the reservoir suspended from said bottom member, and a processor configured to output a weight measurement based on said voltage output.

4. The system of claim 2 , wherein at least one of the first plurality of magnets and second plurality of magnets lies in a same plane and are spaced 120 degrees apart.

5. The system of claim 2 , wherein said magnets comprise Neodymium magnets and said magnets are heated for a predetermined period of time prior to assembly of said system to process irreversible magnetic losses that naturally occur over time with heat.

6. The system of claim 1 , wherein said second plurality of members comprises at least two tracks configured to slidably receive the reservoir.

7. The system of claim 6 , wherein each of said at least two tracks extends along a front to back axis of said dialysis machine and comprises a front end and a back end, and wherein said second plurality of members further comprises a back plate connected to said back ends of said at least two tracks.

8. The system of claim 1 , further comprising at least one flexing structure attached to said top member, wherein said at least one flexing structure is positioned between said top member and said circuit board and is in physical communication with said circuit board, and wherein said at least one flexing structure comprises at least one flexing member for allowing movement of said top member in relation to said circuit board and in tandem with said bottom member.

9. The system of claim 8 , further comprising at least one flexing structure attached to said bottom member, wherein said at least one flexing structure is positioned between said bottom member and said circuit board and is in physical communication with said circuit board, and wherein said at least one flexing structure comprises at least one flexing member for allowing movement of said bottom member in relation to said circuit board and in tandem with said top member.

10. The system of claim 9 , wherein the at least one flexing structure attached to said top member is a flexure ring and wherein said at least one flexing member is a curved arm and the at least one flexing structure attached to said bottom member is a flexure ring and wherein said at least one flexing member is a curved arm.

11. The system of claim 10 , wherein each flexure ring comprises three curved arms displaceable in a same plane about a center portion of said ring as said load is suspended.

12. The system of claim 10 , comprising an additional flexure ring positioned between said top member and said circuit board and an additional flexure ring positioned between said bottom member and said circuit board.

13. The system of claim 12 , wherein said curved arms of said flexure rings are arranged in parallel to minimize out of plane moments of said system.

14. The system of claim 10 , wherein said system includes at least one spacer element between each of said at least one flexure rings and said circuit board.

15. The system of claim 1 , wherein said first connector is adapted to mount to said at least one of said first plurality of members of said frame at a position along a vertical axis extending through a center of said dialysis machine.

16. The system of claim 1 , wherein said second connector is adapted to attach said second plurality of members at a position along a vertical axis extending through a center of said dialysis machine.

17. The system of claim 1 , wherein said circuit board further comprises copper and wherein said copper is adapted to magnetically dampen mechanical oscillations of said load suspended from the system and attached to the bottom member.

18. A method for suspending a load applied by a reservoir inside a dialysis machine, comprising the steps of:
providing said reservoir configured to be in fluid communication with the dialysis machine;
providing a suspension system attached to a point along a vertical axis of said dialysis machine, said system comprising:
a frame having a first plurality of members, said frame defining a structure around which a portion of said dialysis machine is formed;
a top member attached to at least one of said first plurality of members by a first connector;
a bottom member attached to a second plurality of members by a second connector, the second plurality of members being configured to suspend the reservoir; and
a circuit board positioned between said top member and said bottom member;
wherein said top member, bottom member, and circuit board are configured to attach to said frame such that, when the reservoir is placed on said bottom member, the load translates through said bottom member and said top member directly to said frame without placing said load on said circuit board; and,

applying said load to the bottom member of said system by positioning the reservoir on said second plurality of members.

19. The method for suspending a load of claim 18 , wherein said top member further comprises a first plurality of magnets and said bottom member further comprises a second plurality of magnets, wherein said first and second plurality of magnets generate a magnetic field within said system, further wherein said circuit board further comprises a plurality of sensors configured to output a voltage based on sensed displacement of said magnetic field about said circuit board when the load is applied by said reservoir suspended from said bottom member, and a processor configured to output a weight measurement based on said voltage output, said method further comprising the step of using said voltage output of sensors to calculate a weight of contents of said reservoir.

20. The method for suspending a load of claim 19 , wherein said suspension system further comprises:
at least one flexing structure attached to said top member, wherein said at least one flexing structure is positioned between said top member and said circuit board and is in physical communication with said circuit board, and wherein said at least one flexing structure comprises at least one flexing member for allowing movement of said top mem

Assignees

• Fresenius Medical Care Holdings Inc

Inventors

• Fulkerson Barry Neil
• Fazio Joe
• Huang Alec
• Kelly Brian Thomas
• Nolan Tam
• Smith Mark

Classifications

• G01G3/15

  measuring variations of magnetic properties · CPC title

• G01G19/14

  for weighing suspended loads (G01G3/00 takes precedence; incorporation of weighing devices in cranes B66C1/40, B66C13/16) · CPC title

• A61M2205/3393

  by weighing the reservoir · CPC title

• G01G17/04 Primary

  for weighing fluids, e.g. gases, pastes · CPC title

• G01L1/044

  of leaf springs · CPC title