Refrigerator

Abstract: A refrigerator is provided with means (30) for blocking and unblocking a cooling air path to a cooling compartment. Temperatures at, at least, two locations in the cooling compartment are sensed. If the difference between the sensed temperatures is greater than a threshold, the cooling air path is cyclically blocked and unblocked. Furthermore, if the average of the temperatures is above further threshold, the air path is fully unblocked otherwise it is only partially unblocked.

Description: The present invention relates to a method of supplying cooling air to a cooling compartment of a refrigerator, the method comprising the steps of sensing the temperature at a first and second positions plurality of position in a cooling compartment of a refrigerator and controlling the blocking of a cooling air path to the cooling compartment in dependence on the sensed temperature and a refrigerator which operates according to such a method. Such a method is known from GB-A-2201014. In general, as shown in Figure 1, a refrigerator has a compressor 14 for compressing refrigerant, an evaporator 7 for generating cool air by evaporating the refrigerant supplied from the compressor 14, and a fan 10 for blowing the cool air generated by the evaporator 7. A duct member 12 forming a cool air duct is installed at the back of a fresh food compartment 3. The duct member 12 has a plurality of cool air discharge ports 13 opening into the fresh food compartment 3. Cool air blown by the fan 10 flows into the cool air duct, and is then supplied to the fresh food compartment 3 through the cool air discharge ports 13. The fresh food compartment 3 has a door 2, and the fresh food compartment 3 is partitioned into a plurality of spaces by shelves 4. At the upper part of the fresh food compartment 3, a cover 5 for shielding the evaporator 7 is installed. The evaporator 7 is fixed by a holder 8 in a space 6 formed by the cover 5. While the refrigerator is operating, frost forms on the evaporator 7. The cooling efficiency of the evaporator 7 is lowered by the frost. Consequently, the refrigerator is equipped with a heater 9 for removing the frost, and defrosts the evaporator 7 by heating the evaporator 7 using the heater 9 when the refrigerator is has been operating for a predetermined period of time. A temperature sensor (not shown) is installed in the fresh food compartment 3. When the temperature measured by the temperature sensor is higher than a temperature set by a user, the refrigerator begins to operate the compressor 14 and the fan 10. Then the evaporator 7 generates cool air, and the cool air is supplied into the cool air duct by the fan 10. The cool air supplied into the cool air duct is discharged into the fresh food compartment 3 through the cool air discharge ports 13, and thereby the food stored in the fresh food compartment 3 is cooled. GB-A-2201014 discloses an example of a refrigerator to which the present invention may be applied. A method according to the present invention is characterised in that the sensed temperature values are compared and, if the sensed temperature value differential is greater than a threshold value, the cooling air path is cyclically blocked and unblocked. Preferably, an average of the sensed temperature values is taken and if, when the cooling air path is not being cyclically blocked and unblocked, the average is greater than a threshold and, the cooling air path is fully unblocked otherwise the cooling air path is partially unblocked. Preferably, the method includes the step of driving a fan for generating a cooling air flow in the cooling air path, if the average of the sensed temperature values is greater than a user-set temperature, otherwise not driving the fan. A refrigerator according to the present invention includes a cooling air path to a cooling compartment, a fan for generating a cooling air flow in the cooling air path for cooling the cooling compartment, a plurality of temperature sensing means for sensing temperature in the cooling compartment, means for blocking and unblocking the cooling air path and control means responsive to the outputs of the temperature sensing means to operate the refrigerator according to the method of claim 1. Preferably, the refrigerator includes a plurality of cool air discharge ports opening into the cooling compartment and said means for blocking and unblocking the cooling air path comprises opening/closing member for opening/closing the cool air discharge ports for supplying a cooling compartment with cool air and a motor for driving said opening/dosing member. Preferably, said motor is a stepper motor. An embodiment of the present invention will now be described, by way of example, with reference to Figures 2 to 6 of the accompanying drawings, in which:- Figure 1 is a partial cutaway perspective view of a prior art refrigerator; Figure 2 is a block diagram of a control device of a refrigerator according to the present invention; Figures 3 through 5 are side sectional views showing the operation of the opening/closing device controlled by a control method according to the present invention; and Figure 6 is a flow chart showing a control method according to the present invention. In the following description, parts common to the refrigerator according to the present invention and the above-described prior art refrigerator will not be described in detail again. However, the same reference signs are employed. Referring to Figure 2, a refrigerator has a microcomputer 25 for controlling the overall operation of the refrigerator, first and second temperature sensors 21, 22 for measuring the temperature in the fresh food compartment 3, an opening/closing device driving part 26 for driving an opening/closing device, a compressor driving part 27 for driving the compressor 14, and a fan driving part 28 for driving the fan 10. The first and second temperature sensors 21, 22 measure the temperature at the different positions in the fresh food compartment 3. The temperatures measured respectively by the first and second temperature sensors 21, 22 are input into the microcomputer 25. The driving parts 26, 27, 28 are controlled by the microcomputer 25. The opening/closing device 30 for opening and closing the cool air discharge ports 13 is, as shown in Figures 3 through 5, comprises of an opening/closing member 16 disposed near the duct member 12 for opening and closing the cool air discharge ports 13, a motor 17 for driving the opening/closing member 16, and a power transmission 18 for transmitting the power of the motor 17 to the opening/closing member 16. The opening/closing member 16 is formed with a plurality of air holes 16a. According to the position of the opening/closing member 16, the cool air discharge ports 13 of the duct member 12 are open as shown in Figure 3, or closed as shown in Figure 5. The power transmission 18 is comprised of a cam and gears which convert rotational movement of the motor 17 to up-and-down movement of the opening/closing member 16. A reed switch 20 is installed at the bottom of the power transmission 18, and a magnet 19 for operating the reed switch 20 is installed at the bottom of the opening/closing member 16. When the opening/closing member 16 is moved down by the operation of the motor 17, the cool air discharge ports 13 are closed as shown in Figure 3, and the reed switch 20 is closed by the magnet 19. Then, the microcomputer 25 senses the completion of the closing operation of the opening/closing member 16, and stops operating the motor 17. The motor 17 is driven by the opening/closing device driving part 26 controlled by the microcomputer 25. The motor 17 is a stepper motor which can be driven bidirectionally. Since the rotational position of the stepper motor can be precisely controlled, it is easy to control to opening/closing member 16 to position it in open, partially open, and close positions as shown in Figures 3 through 5 respectively. Furthermore, since the motor 17 can be controlled bidirectionally, movement between the positions shown in Figures 3 through 5 is rapidly performed. In other words, if a motor which can be rotated in one direction is adopted, the opening/closing member 16 is moved serially through its positions in the order open, partially open, close, partially open, and open, so a number of steps will be required in order to move it from the partially open position to the open position or to the close position. However, selective and direct movement from the partially open position to the open position or to the close position can be performed according to the rotational direction of the motor 17. Referring to Figure 6, during operation of the refrigerator, the microcomputer 25 measures (step S1) the temperatures R1, R2 at two positions in the fresh food compartment 3 using the first and second temperature sensors 21, 22. The microcomputer 25 calculates (step S2) the average temperature X of the measured temperatures R1, R2. The microcomputer 25 compares (step S3) the average temperature X with a set temperature which is a temperature corresponding to the cooling intensity preset by a user. If the average temperature X of the fresh food compartment 3 is lower than the set temperature, the fresh food compartment 3 is sufficiently cool. Therefore, the microcomputer 25 controls the compressor driving part 27 and the fan driving part 28 to stop (step S4) operation of the compressor 14 and the fan 10, and controls the opening/closing device driving part 26 to close (step S5) the cool air discharge ports 13 as shown in Figure 5. Then, cool air is not generated in the evaporator 7 and the supply of cool air into the fresh food compartment 3 is stopped. If the average temperature X of the fresh food compartment 3 is higher than the set temperature, the fresh food compartment 3 is not sufficiently cool. Accordingly, the microcomputer 25 controls the compressor driving part 27 and the fan driving pat 28 to operate (step S6) the compressor 14 and the fan 10 and the evaporator 7 generates cool air. Then, the microcomputer 25 calculates the difference between the measured temperatures R1, R2, and judges (step S7) whether the temperature difference is more than two degrees centigrade or not. If the temperature difference is more than two degrees centigrade, the microcomputer 25 determines that the temperature in the fresh food compartment 3 is not uniform, and if the temperature difference is less than two degrees centigrade, the microcomputer 25 determines that the temperature in the fresh food compartment 3 is uniform. Here, the criterion for determining whether the temperature in the fresh food compartment 3 is uniform or not is an example. However, a different temperature difference may be used in consideration of the size, kind, etc of the refrigerator. When the temperature difference is higher than two degrees centigrade, the microcomputer 25 drives the motor 17 so that the opening/closing member 16 repeats (step S8) the opening/closing operation of the cool air discharge ports 13. The repetition of the opening/closing operation is performed by driving the motor 17 continuously in one rotational direction. That is, when the motor 17 is driven in one rotational direction continuously, the opening/closing member 16 cycles through its open and close positions which are shown in Figure 3 and Figure 5, respectively. Then, the supply of the cool air through the cool air discharge ports 13 is performed intermittently, and the open degree of the cool air discharge ports 13 varies, whereby the velocity of the cool air discharged through the cool air discharge ports 13 varies. Therefore, the circulation effect of the cool air in the fresh food compartment 3 is enhanced, and thereby the temperature in the fresh food compartment is kept uniform. If the temperature difference is below two degrees centigrade, the microcomputer 25 compares (step S9) the calculated average temperature X with a predetermined temperature. Here, the predetermined temperature is a little higher than the set temperature set by the user. For example, if the temperature set by the user is four degrees centigrade, the predetermined temperature is six degrees centigrade. The predetermined temperature varies according to the set temperature, which is pre-programmed in the microcomputer 25. If the average temperature X is higher than the predetermined temperature, the microcomputer 25 totally opens (step S10) the cool air discharge ports 13 as shown in Figure 3. Then, plenty of cool air is supplied to the fresh food compartment 3 through the cool air discharge ports 13. If the average temperature X is lower than the predetermined temperature, that is, if the average temperature X is between the set temperature and the predetermined temperature, the microcomputer 25 partially opens (step S11) the cool air discharge ports 13 as shown in Figure 4. Then, a small amount of cool air is supplied into the fresh food compartment through the cool air discharge ports 13. According to such a process, the amount of cool air supplied to the fresh food compartment 3 is controlled according to the rising degree of temperature in the fresh food compartment 3, so the temperature in the fresh food compartment 3 is maintained to the set temperature efficiently. As described above, according to the present invention, when the distribution of the temperature in the fresh food compartment is uneven, the cool air discharge ports are cyclically opened and closed so that the temperature in the fresh food compartment becomes uniform. Furthermore, since the amount of supplied cool air is controlled according to the rising degree of the temperature, the set temperature is kept efficiently. In particular, according to the present invention, since the comparison of the set temperature and the temperature in the fresh food compartment is performed on the basis of the average temperature of the temperatures measured at a plurality of positions in the fresh food compartment, overcooling does not occur at one position even when the temperature at the other position rises.

Claims: A method of supplying cooling air to a cooling compartment (3) of a refrigerator, the method comprising the steps of:- sensing the temperature at a first and second positions in a cooling compartment (3) of a refrigerator; and controlling the blocking of a cooling air path to the cooling compartment (3) in dependence on the sensed temperature, characterised in that the sensed temperature values are compared and, if the sensed temperature value differential is greater than a threshold value, the cooling air path is cyclically blocked and unblocked. A method according to claim 1, wherein an average of the sensed temperature values is taken and if, when the cooling air path is not being cyclically blocked and unblocked, the average is greater than a threshold and, the cooling air path is fully unblocked otherwise the cooling air path is partially unblocked. A method according to claim 1 or 2, including the step of driving a fan (10) for generating a cooling air flow in the cooling air path, if the average of the sensed temperature values is greater than a user-set temperature, otherwise not driving the fan (10). A refrigerator including a cooling air path to a cooling compartment (3), a fan (10) for generating a cooling air flow in the cooling air path for cooling the cooling compartment (3), a plurality of temperature sensing means (21, 22) for sensing temperature in the cooling compartment (3), means (30) for blocking and unblocking the cooling air path and control means (25) responsive to the outputs of the temperature sensing means to operate the refrigerator according to any one of claims 1 to 3. A refrigerator according to claim 4, including a plurality of cool air discharge ports (13) opening into the cooling compartment (3) and said means (30) for blocking and unblocking the cooling air path comprises an opening/closing member (16) for opening/closing the cool air discharge ports for supplying a cooling compartment with cool air and a motor (17) for driving said opening/closing member (16). A refrigerator according to claim 5, wherein said motor (17) is a stepper motor.

Inventors: KIM JAE-IN, PARK HAE-JIN, YOO HAN-JOO, KIM, JAE-IN, PARK, HAE-JIN, YOO, HAN-JOO
Applicants: SAMSUNG ELECTRONICS CO LTD, SAMSUNG ELECTRONICS CO., LTD.
Application year: 1998
Main classification: F25D29
IPC codes: F25D17, F24F13, F25D29