# US 2018/0321077 A1 · Load Suspension and Weighing System for a Dialysis Machine Reservoir

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- Number: US 2018/0321077 A1
- Document ID: US20180321077A1
- Status: Published application
- Kind: A1
- Application number: 15/808,189
- Filed: 2017-11-09
- Published: 2018-11-08
- Earliest claimed: 2012-12-24
- Assignees: Fresenius Medical Care Holdings, Inc.
- Applicants: Fresenius Medical Care Holdings, Inc.
- Inventors: Barry Neil Fulkerson; Joe Fazio; Alec Huang; Brian Thomas Kelly; Tam Nolan; Mark Smith
- Web page: https://patentgrep.com/patent/US20180321077A1

## CPC

- G01G 17/04: for weighing fluids, e.g. gases, pastes
- A61M 1/3621: {Extra-corporeal blood circuits (single-needle circuits A61M1/30)}
- B01D 61/30: Accessories; Auxiliary operation
- G01G 3/15: measuring variations of magnetic properties
- G01G 19/14: for weighing suspended loads (G01G3/00 takes precedence; incorporation of weighing devices in cranes B66C1/40, B66C13/16)
- A61M 2205/3393: by weighing the reservoir
- G01L 1/04: by measuring elastic deformation of gauges, e.g. of springs
- G01L 1/044: {of leaf springs}
- G01L 1/046: {of spiral springs}
- G01G: WEIGHING (sorting by weighing B07C5/16)
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)

## 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.

## Claims

### Claim 1

A flexure assembly for weighing and suspending loads, said flexure assembly comprising:
a. a top component comprising a first plurality of magnets;
b. a bottom component comprising a second plurality of magnets, wherein said first plurality of magnets and said second plurality of magnets generate a magnetic field within said flexure assembly;
c. a circuit board positioned between said top assembly and said bottom assembly and comprising a plurality of magnetic field sensors and a processor;
d. at least one flexing structure attached to said top assembly and positioned between said top assembly and said circuit board, wherein said at least one flexing structure comprises at least one flexing member for allowing movement of said top assembly in relation to said circuit board and in tandem with said bottom assembly; and
e. at least one flexing structure attached to said bottom assembly and positioned between said bottom assembly and said circuit board, said at least one flexing structure comprising at least one flexing member for allowing movement of said bottom assembly in relation to said circuit board and in tandem with said top assembly.

### Claim 2 (depends on 1)

The flexure assembly of claim 1 wherein the at least one flexing structure attached to said top assembly is a flexure ring and wherein said at least one flexing member is a curved arm.

### Claim 3 (depends on 2)

The flexure assembly of claim 2 wherein the at least one flexing structure attached to said bottom assembly is a flexure ring and wherein said at least one flexing member is a curved arm.

### Claim 4 (depends on 3)

The flexure assembly of claim 3, comprising an additional flexure ring positioned between said top assembly and said circuit board and an additional flexure ring positioned between said bottom assembly and said circuit board.

### Claim 5 (depends on 1)

The flexure assembly of claim 1, wherein said top assembly is adapted to attach to an attachment point of a dialysis machine and wherein said attachment point is positioned along a vertical axis extending through a center of said dialysis machine.

### Claim 6 (depends on 1)

The flexure assembly of claim 1, wherein said bottom assembly is adapted to attach to an attachment point of a first internal frame of a dialysis machine and wherein said attachment point of the first internal frame is positioned along a vertical axis extending through a center of said dialysis machine.

### Claim 7 (depends on 3)

The flexure assembly of claim 3, wherein said flexure assembly includes at least one spacer element between each of said at least one flexure rings and said circuit board.

### Claim 8 (depends on 1)

The flexure assembly of claim 1 further comprising copper wherein said copper is adapted to magnetically dampen mechanical oscillations of structures suspended from the flexure assembly and attached to the bottom assembly.

### Claim 9 (depends on 3)

The flexure assembly of claim 3, wherein said flexure rings are comprised of aluminum.

### Claim 10

A method for weighing and suspending loads of a reservoir unit of a dialysis machine, comprising the steps of:
a. providing a flexure assembly, said flexure assembly attached to a point along a vertical axis of said dialysis machine, said flexure assembly comprising:
i. a top component comprising a first plurality of magnets;
ii. a bottom component comprising a second plurality of magnets, wherein said first plurality of magnets and said second plurality of magnets generate a magnetic field within said flexure assembly;
iii. a circuit board positioned between said top assembly and said bottom assembly and comprising at least one magnetic field sensor and a processor;
iv. at least one flexing structure attached to said top assembly and positioned between said top assembly and said circuit board, said at least one flexing structure comprising at least one flexing member for allowing movement of said top assembly in relation to said circuit board; and
v. at least one flexing structure attached to said bottom assembly and positioned between said bottom assembly and said circuit board, said at least one flexing structure comprising at least one flexing member for allowing movement of said bottom assembly in relation to said circuit board; and,
b. applying a load to the bottom assembly of said flexure assembly, wherein the application of said load pulls on said flexure assembly, resulting in a displacement of said magnetic field about said circuit board, wherein said at least one magnetic field sensor senses the displacement of the magnetic field and generates a voltage output and wherein said processor receives the voltage output and generates a weight measurement based on the voltage output.

### Claim 11 (depends on 10)

The method for weighing and suspending loads of claim 10 wherein the at least one flexing structure attached to said top assembly is a flexure ring and wherein said at least one flexing member is a curved arm.

### Claim 12 (depends on 11)

The method for weighing and suspending loads of claim 11 wherein the at least one flexing structure attached to said bottom assembly is a flexure ring and wherein said at least one flexing member is a curved arm.

### Claim 13 (depends on 12)

The method for weighing and suspending loads of claim 12 wherein at least one of the flexure ring attached to said bottom assembly or the flexure ring attached to the top assembly comprises aluminum.

### Claim 14 (depends on 12)

The method for weighing and suspending loads of claim 12, comprising an additional flexure ring positioned between said top assembly and said circuit board and an additional flexure ring positioned between said bottom assembly and said circuit board.

### Claim 15 (depends on 11)

The method for weighing and suspending loads of claim 11, wherein the first plurality of magnets lie in a same plane and are spaced 120 degrees apart.

### Claim 16 (depends on 12)

The method for weighing and suspending loads of claim 12, wherein the second plurality of magnets lie in a same plane and are spaced 120 degrees apart.

### Claim 17

A dialysis system having an assembly for weighing and suspending loads, said assembly comprising:
a first component comprising a first plurality of magnets;
a second component comprising a second plurality of magnets, wherein said first plurality of magnets and said second plurality of magnets generate a magnetic field within said assembly; and
a circuit board positioned between said first component and said second component and comprising a plurality of magnetic field sensors for outputting a voltage based on changes to said magnetic field and a processor, wherein said processor is configured to output a weight measurement based on said voltage output.

### Claim 18 (depends on 17)

The dialysis system of claim 17 further comprising at least one flexing structure attached to said first component and positioned between said first component and said circuit board, said at least one flexing structure comprising at least one curved member for allowing movement of said first component in relation to said circuit board.

### Claim 19 (depends on 18)

The dialysis system of claim 18 further comprising at least one flexing structure attached to said second component and positioned between said second component and said circuit board, said at least one flexing structure comprising at least one curved member for allowing movement of said second component in relation to said circuit board.

### Claim 20 (depends on 17)

The dialysis system of claim 17 further comprising a first internal frame attached to said second component, said first internal frame having a top plate attached to said second component, at least two tracks configured to slidably receive a reservoir unit, and a plate having a plurality of electrical contact elements configured to be in physical and electrical contact with a contact plate on said reservoir unit.