Defrost control apparatus and method for a refrigerating system

• US 5,251,454 A
• Filed: 01/30/1992
• Issued: 10/12/1993
• Est. Priority Date: 01/31/1991
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yoon, Kwang H.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/827,336
• Time in Patent Office: 621 Days
• Field of Search: 62/156, 62/155, 62/140, 62/152, 62/154, 62/234, 62/180, 62/186, 62/80, 62/81, 62/82
• US Class Current: 62/156
• CPC Class Codes: F25D 21/006 with electronic control circuits
• CPC Class Codes: F25D 2700/10 Sensors measuring the temperature of the evaporator
• CPC Class Codes: Y10T 74/20486 Drum and cable

Abstract

A thermistor is mounted between the fins of an evaporator. The thermistor senses the temperature about the evaporator when a blow fan mounted at the evaporator is driven and when it halts. The two sensed temperatures are compared, so that when the difference of the two temperatures is below a first set value, a defrost operation starts. When the temperature about the evaporator is above a second set value, the defrost operation is completed.

Claims

1. A refrigerating system including an evaporator, a fan for blowing air through the evaporator and a defrost heater, comprising:

a temperature sensing means disposed near the evaporator;

a microprocessor for obtaining a difference between a temperature sensed by the temperature sensing means when the fan is driven and a temperature sensed by the temperature sensing means when the fan is paused, said microprocessor controlling the fan, initiating a defrost operation by driving the defrost heater when the difference in temperature is less than a first set value, and completing the defrost operation by turning off the defrost heater when the temperature sensed by the temperature sensing means is greater than a second set value.

2. A refrigerating system as claimed in claim 1, which further includes fixing means comprised of two arms coupled to the evaporator at a spaced apart distance, and a frame connecting the two arms and having the temperature sensing means mounted thereon.

3. A refrigerating system as claimed in claim 2, wherein the length of the arms are shorter than the thickness of the permissible frost.

4. A defrost control method for a refrigerating system which periodically detects a temperature about an evaporator by a temperature sensing means mounted in a predetermined space near the evaporator and determines a defrost start time from the sensed temperatures, comprising the steps of:

sensing at least two temperatures with the temperature sensing means, a first temperature being sensed during the driving of the fan and a second temperature being sensed during a pause of the fan;

completing the defrost operation by turning off the defrost heater when the temperature sensed by the temperature sensing means is greater than a second set valve.