Liquid level detection device, accumulator, and air-conditioning apparatus

Patent metadata

Field	Value
Publication number	US-11175172-B2
Application number	US-201816646184-A
Country	US
Kind code	B2
Filing date	Sep 12, 2018
Priority date	Sep 29, 2017
Publication date	Nov 16, 2021
Grant date	Nov 16, 2021

Abstract

A liquid level detection device detecting a liquid level of a liquid in a container includes a heater configured to heat the container, a plurality of temperature sensors provided at different heights of the container, and configured to detect a surface temperature of the container, and a controller configured to detect the liquid level of the liquid in the container, based on the surface temperature of the container detected by the plurality of temperature sensors when the heater is caused to heat.

First claim

The invention claimed is:

1. A liquid level detection device detecting a liquid level of a liquid in a container, comprising:
a plurality of heaters configured to heat the container;
a plurality of temperature sensors provided at different heights of the container, and configured to detect surface temperatures of the container; and
a controller configured to control the heating by the heaters based on the surface temperatures of the container detected by the plurality of temperature sensors, and detect the liquid level of the liquid in the container based on the surface temperatures of the container detected by the plurality of temperature sensors when the heaters are caused to heat;
wherein the plurality of temperature sensors and the plurality of heaters are arranged in an alternating pattern on the container such that the plurality of temperatures sensors do not overlap the plurality of heaters, none of the plurality of temperatures sensors is adjacent to another of the plurality of temperatures sensors, and none of the plurality of heaters is adjacent to another of the plurality of heaters.

2. The liquid level detection device of claim 1 , wherein
the plurality of temperature sensors include
a reference temperature sensor installed at a lowermost portion, and configured to detect a reference temperature, and
a determination temperature sensor installed at a position higher than the reference temperature sensor, and
the controller
calculates a temperature difference between the reference temperature detected by the reference temperature sensor, and a surface temperature detected by the determination temperature sensor,
and
determines a position of the liquid level of the liquid in the container based on comparison of the temperature difference and a threshold for the temperature difference.

3. The liquid level detection device of claim 2 ,
wherein the reference temperature sensor is installed at a position where the liquid exists.

4. The liquid level detection device of claim 2 , wherein
the controller determines that the liquid level of the liquid in the container exists in an area at a lower side from the determination temperature sensor when the temperature difference is the threshold or more.

5. The liquid level detection device of claim 2 , wherein
the controller further includes a notifier configured to notify a determination result by the liquid level determination section.

6. The liquid level detection device of claim 1 , further comprising:
a belt section that is long, wherein the plurality of heaters and the plurality of temperature sensors are provided on the belt section, and
the belt section is wound around the container so that a longitudinal direction of the belt section is along a height direction of the container in such a manner that the plurality of heaters and the plurality of temperature sensors contact a surface of the container.

7. An accumulator that separates refrigerant into liquid refrigerant and gaseous refrigerant, and is the container that stores the liquid refrigerant, wherein
the liquid level detection device of claim 1 is attached, and
the liquid level detection device detects a liquid level of the stored liquid refrigerant.

8. The accumulator of claim 7 , comprising:
a U-shaped outflow pipe having a liquid inlet allowing the liquid refrigerant to flow in and a gas inlet taking in the gaseous refrigerant formed, and allowing the refrigerant flowing in to flow out, wherein
the plurality of temperature sensors include
a first temperature sensor installed at a lowermost portion, and configured to detect a reference temperature, and
a second temperature sensor installed at an uppermost portion,
the first temperature sensor is provided at a lower side from the liquid inlet, and
the second temperature sensor is provided at a lower side from the gas inlet.

9. The accumulator of claim 7 ,
wherein the liquid level detection device is attached to a surface.

10. An air-conditioning apparatus, comprising the accumulator of claim 7 .

11. The air-conditioning apparatus of claim 10 , further comprising:
a compressor in which a suction side of the refrigerant is connected to an outflow side of the refrigerant in the accumulator, and configured to compress the refrigerant flowing out from the accumulator and discharge the refrigerant, wherein
the controller controls a compressor frequency based on a position of a liquid level of the liquid refrigerant that is detected.

12. The air-conditioning apparatus of claim 11 , wherein the controller determines the compressor frequency so that a higher detected liquid level position of the liquid refrigerant results in a lower compressor frequency.

13. The air-conditioning apparatus of claim 12 , further comprising an outside temperature sensor that detects an outside temperature,
wherein
the controller controls the heaters based on the outside temperature detected by the outside temperature sensor, and
when the outside temperature is equal to or lower than a third set temperature, the heaters is turned on.

14. The air-conditioning apparatus of claim 10 , further comprising:
a compressor in which a suction side of the refrigerant is connected to an outflow side of the refrigerant in the accumulator, and configured to compress the refrigerant flowing out from the accumulator and discharge the refrigerant;
a heat exchanger configured to condense the refrigerant;
a bypass configured to bypass a high-pressure side and a low-pressure side of the compressor;
a bypass valve provided in the bypass, and configured to circulate or shut off the refrigerant flowing in the bypass by opening and closing;
a discharge temperature sensor configured to detect a discharge temperature of the refrigerant discharged from the compressor; and
a condensing temperature sensor configured to detect a condensing temperature of the refrigerant flowing in the heat exchanger, wherein
the controller
calculates a difference value between the discharge temperature and the condensing temperature, and control opening and closing of the bypass valve based on the calculated difference value, and a position of the liquid level of the liquid refrigerant that is detected.

15. The air-conditioning apparatus of claim 14 , wherein
the bypass is provided to bypass a discharge side and a suction side of the compressor.

16. The air-conditioning apparatus of claim 14 , wherein
the bypass is provided to bypass a discharge side of the compressor, and an inflow side of the refrigerant in the accumulator.

17. The accumulator of claim 7 , further comprising a refrigerant temperature sensor that detects a temperature of a refrigerant that flows in, wherein
the controller controls the heaters based on the surface temperatures of the container detected by a plurality of the temperature sensors and the refrigerant temperature detected by the refrigerant temperature sensor, and
turns the heaters on when a temperature difference between a first surface temperature of the container detected by a first temperature sensor selected from the plurality of temperature sensors and the refrigerant temperature is equal to or lower than a second set temperature.

18. The liquid level detection device of claim 1 , wherein the controller controls the heaters based on the surface temperatures of the container detected by a plurality of the temperature sensors, and
when the surface temperatures of the container detected by the plurality of temperature sensors are equal to or lower than a first set temp

Assignees

• Mitsubishi Electric Corp

Inventors

• Asanuma Hiroaki
• Okano Hiroyuki
• Okochi Kazuki
• Maruyama Hiroki

Classifications

• G01F23/804

  containing circuits handling parameters other than liquid level · CPC title

• F25B43/00

  Arrangements for separating or purifying gases or liquids (in analysers or rectifiers F25B33/00); Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat (F25B40/00 takes precedence) · CPC title

• G01F23/246 Primary

  thermal devices · CPC title

• G01F23/247 Primary

  for discrete levels · CPC title

• G01F23/0015

  with a whistle or other sonorous signal · CPC title