Liquid level indicating

• US 10,107,667 B2
• Filed: 12/12/2017
• Issued: 10/23/2018
• Est. Priority Date: 10/28/2015
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Cumbie, Michael W., Browning, Robert N. K.
• Primary Examiner(s): West, Paul
• Application Number:
  US15/839,587
• Publication Number:
  US 20180100753A1
• Time in Patent Office: 315 Days
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B41J 2/17566 Ink level or ink residue control
• CPC Class Codes: B41J 2/195 for monitoring ink quality
• CPC Class Codes: B41J 2002/17579 Measuring electrical impedance for ink level indication
• CPC Class Codes: G01F 23/22 by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water involving the use of floats G01F23/30
• CPC Class Codes: G01F 23/246 thermal devices
• CPC Class Codes: G01F 23/247 for discrete levels
• CPC Class Codes: G01F 23/248 Constructional details; Mounting of probes
• CPC Class Codes: H05B 3/82 Fixedly-mounted immersion heaters

Abstract

Examples provide a series of heaters supported at different depths within the volume. A series of temperature sensors is supported at different depths within the volume. The temperature sensors output signals indicative of dissipation of heat from the heaters to indicate a level of the liquid within the volume.

Claims

1. An apparatus comprising:

an elongated strip to extend into a volume containing a liquid;

a series of heaters supported by the strip along the strip, each of the heaters at a different location along the strip that corresponds to a different depth within the volume when the strip extends into the volume; and

a series of temperature sensors supported by the strip along the strip, each of the temperature sensors at a different location along the strip that corresponds to a different depth within the volume when the strip extends into the volume, wherein the series of heaters and the series of temperature sensors are supported by a same surface of the strip, wherein the temperature sensors are to output signals indicative of dissipation of heat from the heaters to indicate a level of the liquid within the volume, and

wherein the series of heaters and the series of temperature sensors form a series of stacks supported by the same surface of the strip, each respective stack in the series of stacks comprising a respective heater and a respective temperature sensor that are one over another in respective different layers above the same surface of the strip.

2. The apparatus of claim 1, wherein the elongated strip comprises silicon.

3. The apparatus of claim 1, wherein the series of heaters and the series of temperature sensors are encapsulated.

4. The apparatus of claim 1, wherein the series of stacks are arranged as an array of stacks along a length of the elongated strip.

5. The apparatus of claim 1, further comprising an encapsulation layer extending over a first stack of the stacks to protect at least one of the heater and temperature sensor in the first stack from the liquid.

6. The apparatus of claim 1, wherein the heaters and the temperature sensors are separate and distinct.

7. The apparatus of claim 1, wherein each of the heaters comprises a resistor.

8. The apparatus of claim 1, further comprising:

a chamber defining the volume to contain the liquid; and

a print head fluidly coupled to the chamber to receive liquid from the volume.

9. The apparatus of claim 1, further comprising a processing unit to receive a signal output by a temperature sensor of the temperature sensors and to determine a level of the liquid within the volume based upon the signal.

10. The apparatus of claim 1, further comprising:

a carrier supporting the elongated strip, wherein the elongated strip comprises;

a first layer over the same surface supporting the series of heaters; and

a second layer over the same surface supporting the series of temperature sensors.

11. The apparatus of claim 1, wherein activation of each respective heater of the series of heaters generates a heat pulse for sensing by a respective temperature sensor of the series of temperature sensors.

12. A liquid container comprising:

a chamber having a volume to contain a liquid;

a strip;

a series of heaters supported by a first surface of the strip along the chamber, the heaters at different depths within the volume; and

a series of temperature sensors supported by the first surface of the strip along the chamber, the temperature sensors at different depths within the volume, wherein the temperature sensors are to output signals in response to heat pulses from the heaters, the signals indicating a level of the liquid within the volume;

wherein the series of heaters and the series of temperature sensors form a series of stacks supported by the first surface of the strip, each respective stack in the series of stacks comprising a respective heater and a respective temperature sensor that are one over another in respective different layers above the first surface of the strip.

13. The liquid container of claim 12, wherein each of the heaters comprises a resistor.

14. The liquid container of claim 12, further comprising:

a carrier supporting the strip, wherein the strip comprises;

a first layer over the first surface supporting the series of heaters; and

a second layer over the first surface supporting the series of temperature sensors.

15. The liquid container of claim 12, wherein the series of heaters and the series of temperature sensors are encapsulated.

16. The liquid container of claim 12, further comprising an encapsulation layer extending over a first stack of the stacks to protect at least one of the heater and temperature sensor in the first stack from the liquid.