Fluid level sensor

Patent metadata

Field	Value
Publication number	US-9476752-B2
Application number	US-201414504136-A
Country	US
Kind code	B2
Filing date	Oct 1, 2014
Priority date	Oct 1, 2014
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

A capacitive fluid level sensor is provided for receiving data indicative of the level of fluid remaining in a fluid container. In various embodiments, the capacitive fluid level sensor may be spaced below and a distance away from the fluid container to be measured, and may comprise a fluid level sensor and an ambient sensor, wherein the fluid level sensor and the ambient sensor are coplanar. In various embodiments, the ambient sensor may be spaced a distance away from the fluid level sensor, such that electric fields generated by the fluid level sensor and the ambient sensor, respectively, do not overlap. Based at least in part on capacitance levels determined by the fluid level sensor and the ambient sensor, the fluid level sensor may generate data indicative of the fluid level in at least a portion of the fluid container located above the fluid level sensor.

First claim

That which is claimed:

1. A fluid dispensing system comprising:
a container defining an internal fluid volume configured for storing and dispensing fluid;
a target capacitance sensor comprising a target transmitter electrode and a target receiver electrode that are coplanar with one another and positioned a distance away from the container, the target capacitance sensor being configured to generate a target electric field to detect a capacitance of a target zone comprising a target portion of the container's internal fluid volume;
an ambient capacitance sensor comprising an ambient transmitter electrode and an ambient receiver electrode that are positioned a distance away from the container, the ambient capacitance sensor being configured to generate an ambient electric field to detect a capacitance of an ambient zone outside of the container; and
one or more processors in communication with the target capacitance sensor and the ambient capacitance sensor, the one or more processors configured to generate a signal indicative of the level of fluid present within the internal fluid volume based at least in part on the capacitance detected by the target capacitance sensor and the capacitance detected by the ambient capacitance sensor.

2. The fluid dispensing system of claim 1 , wherein the target capacitance sensor is positioned such that it is aligned with the target portion of the container, and wherein the ambient capacitance sensor is positioned such that it is not aligned with the container.

3. The fluid dispensing system of claim 2 , wherein:
the target capacitance sensor is aligned with the target portion of the container such that a vertical axis perpendicular to a face of the target transmitter electrode extends through the target portion of the container and the target capacitance sensor.

4. The fluid dispensing system of claim 2 , wherein the target capacitance sensor is positioned below the target portion of the container.

5. The fluid dispensing system of claim 2 , wherein the ambient transmitter electrode and the ambient receiver electrode are coplanar with one another and coplanar with the target transmitter electrode and the target receiver electrode.

6. The fluid dispensing system of claim 1 , wherein the target zone and the ambient zone do not substantially overlap.

7. The fluid dispensing system of claim 1 , further comprising a housing configured to receive the container, and wherein:
the container is removable from the housing; and
the target capacitance sensor and ambient capacitance sensor are provided on a printed circuit board secured to the housing.

8. The fluid dispensing system of claim 1 , wherein the signal indicative of the level of fluid present within the internal fluid volume comprises a signal indicating that the level of fluid in the internal fluid volume is less than a predefined threshold fluid level.

9. The fluid dispensing system of claim 8 , wherein the one or more processors are additionally configured to:
determine a differential capacitance based at least in part on the capacitance detected by the target capacitance sensor and the capacitance detected by the ambient capacitance sensor;
monitor changes in the differential capacitance over time; and
generate the signal indicative of the level of fluid present within the internal fluid volume upon determining that the differential capacitance has changed more than a threshold amount over a predefined increment of time.

10. The fluid dispending system of claim 8 , further comprising a fluid pump, and wherein:
the one or more processors are further configured to disable the fluid pump upon determining that the level of fluid within the fluid volume is less than the predefined threshold fluid level.

11. The fluid dispensing system of claim 1 , wherein the container is a first container and the target capacitance sensor is a first target capacitance sensor, the system additionally comprising:
a second container defining a second internal fluid volume configured for storing and dispensing fluid; and
a second target capacitance sensor comprising a second target transmitter electrode and a second target receiver electrode that are coplanar with one another and positioned a distance away from the second container, the second target capacitance sensor being configured to generate a second target electric field to detect a capacitance of a second target zone comprising a target portion of the second container's second internal fluid volume; and wherein:
the one or more processors are in communication with the second target capacitance sensor and the ambient capacitance sensor, the one or more processors configured to generate a signal indicative of the level of fluid present within the second internal fluid volume based at least in part on the capacitance detected by the second target capacitance sensor and the capacitance detected by the ambient capacitance sensor.

12. The fluid dispensing system of claim 11 , wherein the second target capacitance sensor is positioned such that it is aligned with the target portion of the second container, and wherein the ambient capacitance sensor is positioned such that it is not aligned with the second container.

13. The fluid dispensing system of claim 11 , wherein:
the ambient capacitance sensor comprises:
a first ambient capacitance sensor comprising the ambient transmitter electrode and the ambient receiver electrode; and
a second ambient capacitance sensor comprising a second ambient transmitter electrode and a second ambient receiver electrode that are positioned a distance away from the second container, the second ambient capacitance sensor being configured to generate a second ambient electric field to detect a capacitance of a second ambient zone outside of the second container; and

the one or more processors are in communication with the first target capacitance sensor, the first ambient capacitance sensor, the second target capacitance sensor, and the second ambient capacitance sensor, the one or more processors configured to generate a signal indicative of the level of fluid present within the second internal fluid volume based at least in part on the capacitance detected by the second target capacitance sensor and the capacitance detected by the second ambient capacitance sensor.

14. The fluid dispensing system of claim 13 , wherein the first target capacitance sensor, first ambient capacitance sensor, second ambient capacitance sensor, and second target capacitance sensor are coplanar with one another.

15. A capacitive fluid level sensing device comprising:
a target capacitance sensor comprising a target transmitter electrode and a target receiver electrode that are coplanar with one another, the target capacitance sensor being configured to generate a target electric field to detect a target capacitance of a target zone;
an ambient capacitance sensor comprising an ambient transmitter electrode and an ambient receiver electrode that are coplanar with one another and coplanar with the target transmitter electrode and the target receiver electrode, the ambient capacitance sensor being configured to generate an ambient electric field to detect an ambient capacitance of an ambient zone, wherein the ambient zone does not substantially overlap the target zone; and
one or more processors configured to:
determine a combined capacitance measurement based at least in part on a differential between the target capacitance and the ambient capacitance; and
generate a signal indicative of the combined capacitance measurement.

16. The capacitive fluid level s

Assignees

• Sealed Air Corp

Inventors

• Vilag Brian Vincent
• Mierzejewski Kenneth

Classifications

• G01F23/268

  mounting arrangements of probes · CPC title

• G01F23/263 Primary

  by measuring variations in capacitance of capacitors · CPC title

• B67D7/3272

  using pumps · CPC title

• G01F23/266

  measuring circuits therefor · CPC title

• G01F23/265 Primary

  for discrete levels · CPC title