Smart shunt devices and methods

Patent metadata

Field	Value
Publication number	US-9861524-B2
Application number	US-201414213170-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Mar 14, 2013
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

Devices and methods for the measurement and control of fluid using one or two capacitors are described. The devices use Micro-Electro-Mechanical-Systems (MEMS) and radio-frequency inductive coupling to sense the properties of a fluid in a tube. The single and double capacitor devices may be coupled to shunts implantable in a patient and operable to be interrogated non-invasively. The shunts employing the novel capacitor devices are insensitive to stray signals such as the orientation of a patient's head. The devices are operable to employ a wireless external spectrometer to measure passive subcutaneous components.

First claim

What is claimed is:

1. A device comprising a micro-electromechanical system (MEMS) sensor having a single capacitor, comprising a rigid capacitor plate and a flexible capacitor plate separated by a distance forming a gap, wherein the flexible capacitor plate is operable to deform in response to pressure exerted by a fluid, wherein the capacitor plates are coupled to an inductor forming a capacitor-inductor loop, wherein the device is operable to convert deformation of the flexible capacitor plate into a change in a resonant absorption of the capacitor-inductor loop.

2. The device according to claim 1 further comprising an external circuit operable to induce an alternating current in the capacitor-inductor loop and measure the absorption resonance to convert the deformation of the flexible capacitor plate in response to the fluid into a change in capacitance.

3. The device according to claim 1 wherein at least one of the capacitor plates includes a surface at least partially coated with an oil.

4. The device according to claim 1 comprising a vent extending from the gap operable to permit background pressure at the sensor to be cancelled by a differential measurement.

5. The device according to claim 1 comprising a flow sensor comprising a chamber formed between an inlet of the fluid-conveying channel and the flexible capacitor plate, the chamber operable to receive fluid exiting the channel and further comprising an outlet formed in the chamber to permit flow of the fluid out of the chamber, wherein pressure of the fluid in the chamber causes the flexible capacitor plate to deform toward the rigid capacitor plate and thereby reduce the separation between the flexible and rigid capacitor plates and reduce the capacitance relative to the capacitance when no flowing fluid is present.

6. The device according to claim 5 wherein the fluid exits the outlet to a tube with a calibrated flow resistance to contact an opposite side of the flexible capacitor plate, wherein the device measures a pressure difference across the membrane.

7. The device according to claim 1 comprising a pressure sensor further comprising a shunt tube comprising an opening adjacent a chamber formed adjacent the flexible capacitor plate, wherein pressure of the fluid is transmitted through the fluid to the chamber.

8. The device according to claim 7 , wherein the gap between the capacitor plates is sealed and comprises a fixed quantity of gas, and wherein a change in pressure of the fluid changes the capacitance and resonant property of the capacitor-inductor loop.

9. The device according to claim 1 coupled to a shunt operable to be implanted in a body of a patient, wherein the flexible capacitor plate is positioned to be in fluid connection with a fluid-conveying channel of the shunt.

10. The device according to claim 9 wherein the shunt is an ocular shunt.

11. The device according to claim 9 further comprising a flow regulation device comprising a valve disposed in the channel of the shunt.

12. A device comprising a micro-electromechanical system (MEMS) sensor having a single capacitor, comprising two flexible capacitor plates separated by a distance forming a gap, wherein the flexible capacitor plates are operable to contact a fluid and deform in response to pressure exerted by the fluid, wherein the flexible capacitor plates are coupled to an inductor forming a capacitor-inductor loop, wherein the device is operable to convert deformation of the flexible capacitor plates into a change in a resonant absorption of the capacitor-inductor loop.

13. The device according to claim 12 wherein the capacitor comprises two chips bonded together, wherein each chip comprises a rigid structure housing a flexible capacitor plate.

14. The device according to claim 12 further comprising an external circuit operable to induce an alternating current in the capacitor-inductor loop and measure the absorption resonance to convert the deformation of the flexible capacitor plate in response to the fluid into a change in capacitance.

15. The device according to claim 12 comprising a vent extending from the gap operable to permit background pressure at the sensor to be cancelled by a differential measurement.

Assignees

• New Jersey Inst Technology

Inventors

• Thomas Gordon Albert
• Farrow Reginald Conway
• Kanwal Alokik

Classifications

• G01L9/0073

  using a semiconductive diaphragm · CPC title

• G01L9/0072

  using variations in capacitance · CPC title

• G01L9/007

  using variations in inductance · CPC title

• G01F1/64

  by measuring electrical currents passing through the fluid flow; measuring electrical potential generated by the fluid flow, e.g. by electrochemical, contact or friction effects (G01F1/58 takes precedence) · CPC title

• A61M2205/0244

  Micromachined materials, e.g. made from silicon wafers, microelectromechanical systems [MEMS] or comprising nanotechnology · CPC title