Pressure Measurement Devices, Methods, and Systems

Patent metadata

Field	Value
Publication number	US-2023112605-A1
Application number	US-202218078299-A
Country	US
Kind code	A1
Filing date	Dec 9, 2022
Priority date	May 31, 2011
Publication date	Apr 13, 2023
Grant date	—

Abstract

A method for measuring pressure includes securing a flow channel to a chassis of a measurement device, the flow channel having a flexible wall with a first mechanical engagement feature presented from an external surface thereof. The method also includes engaging the mechanical engagement feature with a complementary engagement member connected to a force transducer, the securing being effective to immobilize the flow channel relative to the force transducer, and detecting at least one of the position and orientation of the of the flow channel relative to transducer and comparing to at least one of a predefined position and orientation. Further, the method includes generating a signal responsive to the detecting, flowing a fluid through the flow channel, and transmitting forces caused by displacement of the flexible wall through the complementary engagement member to the force transducer. Further, electrical signals are generated responsively to a state of the force transducer.

First claim

What is claimed is:

1 . A method for measuring pressure, comprising:
securing a flow channel to a chassis of a measurement device, the flow channel having a flexible wall with a first mechanical engagement feature presented from an external surface thereof; engaging the first mechanical engagement feature with a complementary engagement member connected to a force transducer; the securing being effective to immobilize the flow channel relative to the force transducer; detecting at least one of a position and orientation of the of the flow channel relative to transducer and comparing to at least one of a predefined position and orientation; generating a signal responsive to the detecting; flowing a fluid through the flow channel; transmitting forces caused by displacement of the flexible wall through the complementary engagement member to the force transducer; and generating electrical signals responsively to a state of the force transducer and converting the electrical signals to an indication of pressure.

2 . The method of claim 1 , wherein the securing includes forcing the flow channel to the chassis and preventing movement of the flow channel relative to the chassis.

3 . The method of claim 1 , wherein the securing includes activating a single drive through a mechanical actuator to cause the engaging and the securing.

4 . The method of claim 3 , wherein the mechanical actuator includes a pair of cams.

5 . The method of claim 1 , wherein the flowing includes flowing blood.

6 . The method of claim 5 , wherein the flowing includes flowing the fluid through a first portion connected to a first port with a first cross-sectional shape that transitions to a second portion connected to a second port that has a second cross-sectional shape, wherein the first and second cross-sectional shapes are constant or enlarge toward a respective access of the port such that an internal portion of the flow channel may be formed by pins that can be withdrawn from the flow channel after molding it.

7 . The method of claim 5 , wherein the flowing includes flowing the fluid through a first portion connected to a first port with a first cross-sectional shape that transitions to a second portion connected to a second port that has a second cross-sectional shape, wherein the first and second cross-sectional shapes are constant or enlarge toward a respective access of the port such that the flow channel has no more than one internal flow area expansion in either flow direction.

8 . The method of claim 1 , wherein the flow channel is a self-supporting rigid pod structure with a fluid channel therethrough.

9 . The method of claim 1 , wherein the engaging includes clamping the first mechanical engagement feature.

10 . The method of claim 9 , wherein the first mechanical engagement feature includes a protrusion.

11 . The method of claim 1 , wherein the engaging includes using a motion that includes no urging of the first mechanical engagement feature.

12 . A pressure measuring system, comprising:
a pressure pod with a diaphragm and inlet and outlet ports fluidly coupled to a chamber within the pressure pod, a first surface of the diaphragm facing the chamber and forming a major part of a wall of the chamber and a second major surface of the diaphragm facing away from the chamber and carrying a mechanical engagement feature thereon; a force measuring station having a mechanical engagement member configured to engage with the mechanical engagement feature of the diaphragm, the mechanical engagement member and the mechanical engagement feature of the diaphragm being operable to permit the diaphragm to apply a pulling force to the mechanical engagement member, which force is in a direction tending to move the diaphragm toward the chamber upon application of a negative pressure within the chamber, wherein the force measuring station is configured to generate a signal responsively to a force applied to the mechanical engagement feature.

13 . The system of claim 12 , wherein the chamber has a hemicylindrical shape whose wall flows smoothly into a full cylindrical shape of one of the inlet port and the outlet port.

14 . A pressure measurement pod for use in blood circuits, comprising:
a pressure sensing pod including a chamber; the pod defining a flexible, moveable, fluid-impermeable diaphragm having a first major side thereof facing an interior of the chamber and a second major side opposite the first major side; the second major side facing outwardly away from the chamber, the diaphragm having an engagement component configured to engage an external force measurement device from the second major side; the pod having ports on opposite sides of the chamber or the diaphragm first major side, the chamber having a major dimension perpendicular to an axis of one of the ports that is the same or smaller than an internal dimension of one of the one of the ports.

15 . The pod of claim 14 , wherein the chamber has a cylindrical interior surface.

16 . The pod of claim 14 , wherein the engagement component includes at least one of a projection integral with the diaphragm, a magnet, a ferromagnetic material or member, a Velcro fastener, a hook, an eye, a threaded recess, a threaded projection, a blade lock, a snap, and a surface with an adhesive face.

17 . The pod of any of claim 14 wherein the engagement component includes a fastener.

Assignees

• Nxstage Medical Inc

Inventors

• Brugger James M
• Treu Dennis M
• Burbank Jeffrey H
• Newell Scott W
• Schnell William J
• Buckler Kenneth E

Classifications

• G01L19/0046

  using isolation membranes (G01L13/026 and G01L19/0645 take precedence) · CPC title

• A61M1/3659

  Cannulae pertaining to extracorporeal circulation · CPC title

• G01L19/003

  using a detachable interface or adapter between the process medium and the pressure gauge · CPC title

• G01L19/0023

  for flowthrough systems having a flexible pressure transmitting element · CPC title

• G01L9/006 Primary

  of metallic strain gauges fixed to an element other than the pressure transmitting diaphragm · CPC title