REFRIGERATOR AND CONTROLLING METHOD THEREOF

• US 20130042638A1
• Filed: 02/17/2011
• Published: 02/21/2013
• Est. Priority Date: 02/23/2010
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Hoyoun, Kim, Youngjin, Eom, Yonghwan
• Granted Patent: US 9,328,953 B2
• Time in Patent Office: Days
• US Class Current: 62/80
• CPC Class Codes: F25B 2700/111 using an emitter and receiver, e.g. sensing by emitting light or other radiation and receiving reflection by a sensor
• CPC Class Codes: F25D 21/006 with electronic control circuits
• CPC Class Codes: F25D 21/02 Detecting the presence of frost or condensate
• CPC Class Codes: F25D 21/06 Removing frost defrosting cycles F25B47/02
• CPC Class Codes: F25D 2700/02 Sensors detecting door opening
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/0251 Solidification, icing, curing composites, polymerisation
• CPC Class Codes: G01N 2291/102 one emitter, one receiver
• CPC Class Codes: G01N 29/48 by amplitude comparison

Abstract

The refrigerator of the present invention comprises: a refrigeration cycle composed of a compressor, a condenser and an expansion unit; an evaporator for evaporating a refrigerant which passes through the expansion unit; a heating unit for providing the heat for defrosting the evaporator; and a frost sensor unit which is provided at one side of the evaporator for sensing the amount of frost on the evaporator, and is characterized in that an operation of the frost sensor unit is started on the basis of whether operation conditions of the frost sensor unit are recognized and the heating unit selectively generates the heat according to the sensed result of the frost sensor unit. According to one embodiment of the present invention, the amount of frost on the evaporator is easily determined by the operation of the frost sensor unit and the evaporator is effectively defrosted according to the amount of frost determined thereby.

Claims

1. A refrigerator:

a compressor, a condenser, and an expansion unit that constitute a refrigeration cycle;

an evaporator that evaporates a refrigerant that has passed through the expansion unit;

a heating unit that provides heat for defrosting the evaporator; and

a frost sensor unit that is provided at one side of the evaporator to sense the amount of frost on the evaporator,

wherein the operation of the frost sensor unit starts on the basis of whether operation conditions of the frost sensor unit are recognized and the heating unit selectively generates heat in accordance with the sensing result of the frost sensor unit.

2. The refrigerator of claim 1, wherein the frost sensor unit includes:

a sound-source transmitting unit that generates a sound-source of a first volume to the evaporator; and

a sound-source receiving unit that receives a sound-source of a second volume formed after the sound-source transmitted by the sound-source transmitting unit reflects from or passes through the evaporator.

3. The refrigerator of claim 2, further comprising a control unit that controls the heating unit to generate heat, when the difference between the first volume and the second volume reaches a predetermined value.

4. The refrigerator of claim 2, wherein the sound-source transmitting unit is a sound wave transmitting unit that transmits a sound wave within the audio frequency band or an ultrasonic wave transmitting unit that transmits an ultrasonic wave at the audio frequency band or more.

5. The refrigerator of claim 2, wherein the sound-source receiving unit includes a microphone or an ultrasonic wave sensor.

6. The refrigerator of claim 2, wherein the sound-source transmitting unit and the sound-source receiving unit are provided at one side of the evaporator, respectively, and

the sound-source of the second volume is a sound-source generated by the sound-source of the first volume reflected from the evaporator.

7. The refrigerator of claim 2, wherein the sound-source receiving unit is disposed opposite the sound-source transmitting unit with the evaporator therebweteen, and the sound-source of the second volume is a soundsource generated by the sound-source of the first volume passing through the evaporator.

8. The refrigerator of claim 1, wherein the difference value between the first volume and the second volume changes in proportion to the amount of frost generated on the evaporator.

9. The refrigerator of claim 1, wherein the frost sensor unit includes a photographing device that is provided at one side of the evaporator and operates to photograph the evaporator.

10. The refrigerator of claim 9, wherein the photographing device includes:

a photographing unit that photographs frost on the evaporator and the surrounding background; and

a lighting unit that emits light to the evaporator when the photographing unit takes a picture.

11. The refrigerator of claim 9, further comprising a control unit that determines the amount of frost on the evaporator from the image taken by the photographing device and controls the heating unit to operate when the amount of frost exceeds a predetermined amount.

12. The refrigerator of claim 11, wherein the control unit acquires pixels values that are proportioned to the amount of frost on the evaporator by applying image processing.

13. The refrigerator of claim 12, wherein the image processing includes binarization that separates the frost from other images in the acquired image to determine the amount of frost on the evaporator.

14. The refrigerator of claim 1, wherein the operational conditions include whether an operation time of the refrigeration cycle has passed a predetermined time.

15. The refrigerator of claim 1, further comprising:

a storage chamber where cold air is supplied; and

a door that selectively close the storage chamber,

wherein the operational conditions include whether the number of times of opening the door is a predetermined number of times or more or whether the open time of the door has passed a predetermined time.

16. A refrigerator comprising:

a storage chamber where reserves are cooled and stored;

an evaporator that supplies cold air to the storage chamber;

a defrosting heater that removes frost generated on the surface of the evaporator;

a transmitting unit that is provided at one side of the evaporator and transmits a sound wave or an ultrasonic signal of a predetermined magnitude;

a receiving unit that receives a signal of a magnitude smaller than that of the sound wave or the ultrasonic signal; and

a control unit that controls the defrosting heater to operate, when the magnitude of the signal received by the receiving unit is smaller than a predetermined value.

17. The refrigerator of claim 16, wherein the transmitting unit transmits an ultrasonic signal and the receiving unit is the transmitting unit.

18. The refrigerator of claim 16, wherein the signal received by the receiving unit is a signal reflecting from or passing through a refrigerant pipe or cooling fins that are provided in the evaporator.

19. The refrigerator of claim 16, wherein the transmitting unit and the receiving unit operate with a cycle of a predetermined time interval.

20. A method of controlling a refrigerator, comprising:

exchanging heat in an evaporator, when a refrigeration cycle is performed;

operating a frost sensor unit that senses the amount of frost on the evaporator, when a predetermined condition is satisfied;

recognizing the amount of frost on the evaporator; and

determining operation of a heating unit on the basis of whether the amount of frost is a predetermined value or more.

21. The method of claim 20, wherein whether the predetermined condition is satisfied is determined in accordance with whether an operation time of the refrigeration cycle, the number of opening refrigerator doors, and the open time of the doors are predetermined values or more.

22. The method of claim 20, wherein the operating of a frost sensor unit includes:

transmitting a sound-source signal from a soundsource transmitting unit; and

sensing the sound-source signal with a soundsource receiving unit.

23. The method of claim 20, wherein the operating of a frost sensor unit includes:

photographing the evaporator with a photographing unit; and

extracting pixels corresponding to frosting on the evaporator by applying binarization to an image of the evaporator.