JPS58158477A - Controller for defrostation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a defrosting control device for a refrigerator-freezer or the like.

In general, in various types of cooling devices such as refrigerators, frost adhering to the surface of the cooler is one of the main causes of lowering the cooling capacity, and p1 defrosting measures are important.

In the past, most defrosting devices used a timer to integrate the operating time of the compressor and start defrosting when the integrated time reached a predetermined time. In the case of the above type, defrosting is performed regardless of the amount of frost, so it is not preferable from the viewpoint of energy saving.

On the other hand, if a frost sensor is used to detect the amount of frost and defrosting is performed according to the amount of frost, unnecessary defrosting can be avoided and efficient defrosting control can be expected.

However, the state of frost on the cooler varies greatly depending on environmental conditions, etc., especially when frost grows rapidly in one part, the air flow changes; In some cases, frost may stop forming near the frost sensor and the output of the frost sensor may no longer change. In this case, the frost sensor cannot detect frost formation, so
There was a drawback that defrosting could not be carried out for any length of time.

The present invention has been made in view of the above-mentioned problems, and it is possible to obtain a highly reliable defrost control device that defrosts reliably by starting defrosting within a predetermined time regardless of the output of a frost sensor. That is.

A detailed explanation will be given below using an example shown in the drawings.

Fig. 1 is a block diagram of the device of the present invention, in which 1 is a microprocessor used for control, and 66 is a frost detection device that can easily be provided with a timer function using software. The sensor is, for example, an optical transmission type box sensor having characteristics as shown in curve (a) in FIG. 2, and detects the frosting state based on an increase or decrease in the amount of light from a light emitting diode.

7 is a conventionally used temperature sensor for detecting the end of defrosting, which senses when the frost melts and the temperature around the cooler rises due to the operation of the defrosting circuit (not shown). This is to stop the defrosting circuit. 8 is a relay for switching between cooling operation and defrosting operation, and output port 4
Through the microprocessor 1, either the cooling operation or the defrosting operation can be switched.

Note that 5 is a comparator and 2 is a memory.

Now, in Fig. 2, frost amount M (frost sensor output V +
) to start defrosting.

When power is supplied, the microprocessor 1 first checks whether the output of the frost sensor 6 is below the detection level Vl or not through the input port 3 to the comparator 5! ! l) Check. When the output of the frost sensor 6 is below the level v1, the relay 8 is switched to the defrosting operation, otherwise the relay 8 is switched to the cooling operation through the output port 4.

During the cooling operation, the output of the frost sensor 6 is monitored while integrating the operation time of the microprocessor-Nd compressor, and if the amount falls below the reference level V1, it is determined that the frost amount is the amount that should be defrosted, and the defrosting operation is started. Switch to . Also, during the defrosting operation, the output of the temperature sensor 7 is monitored, and when the temperature reaches a predetermined temperature or higher, it is determined that the defrosting has ended and the operation is switched to the cooling operation.

On the other hand, as described above, the state of frost on the cooler varies greatly depending on environmental conditions and the like, and there may be cases where frost growth stops around the installation location of the frost sensor 6. in this case,
Since the output of the frost sensor 6 does not reach the reference level for any length of time, defrosting will not be performed if the microprocessor 1 simply monitors the output of the frost sensor 6.

Therefore, in the present invention, the above-mentioned microprocessor
1 is provided with a timer defrosting start means for starting defrosting regardless of the output level of the frost sensor 6 when the cumulative value of the operating time of the compressor reaches a predetermined time.

Therefore, even if the output of the frost sensor 6 does not reach the reference level no matter how long it takes, if the cumulative operating time of the compressor reaches a predetermined time, the timer defrosting start means is activated and the defrosting circuit is driven. Once the defrosting circuit is activated and defrosting is performed, the output of the frost sensor 6 is restored and normal operation is resumed.

FIG. 3 shows a flowchart of the apparatus of the present invention.

First, press the start button to supply power and step S
Set to the initial state with 1.

Next, in step S2, a signal from the frost sensor 6 is input through the input port 3, and the presence or absence of frost formation is determined within the microprocessor 1.

If there is no frost at all, or if the amount of frost is below a predetermined amount (No), the process moves to step S8, where a cooling operation is performed by the operation of the output port 4 and the relay 8. It will be done.

At this time, if the frost detection is YES, the process moves to step S8, where the defrosting operation is switched via the output port 4 and the relay 8, and then the process proceeds to step S9, where it is determined whether the defrosting operation has ended or not. Detected by temperature sensor 7.

In step S4, frost formation detection is performed at predetermined intervals during the cooling operation, and if YES, the process proceeds to step S8, and if NO, the process proceeds to step S5. In step S5, it is determined whether the compressor is ON or OFF, and if the compressor is OFF, the process returns to step 4, and if the compressor is ON, the process moves to steno'7's6, where the timer defrosting starting means is activated. A timer count is performed.

Then, in step S7, it is determined whether or not the timer count has reached a predetermined time. If NO, the process returns to step S4, and if YES, the process proceeds to step S8.

Note that when the defrosting operation is started in step 'Ss, the timer count is set to the initial state. Therefore, if there is no abnormality in the frost sensor 6, the frost sensor 6 is activated and defrosting is performed before the timer count of the timer defrosting starting means reaches a predetermined time.

As described above, the present invention provides a defrosting control device that detects frost formation using a frost sensor and performs defrosting, which is equipped with a timer defrosting start means for starting defrosting regardless of the output of the sensor. Therefore, defrosting can be reliably performed while taking advantage of the defrosting characteristics of the frost sensor, and a remarkable effect can be achieved in that highly reliable defrosting control can be performed.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of the device of the present invention, FIG. 2 is a diagram showing the output characteristics of a frost sensor used in the device of the present invention, and FIG. 3 is a flowchart of the device of the present invention. I: Microprocessor, 6° frost sensor.

Claims (1)

[Claims] 1. In a defrost control device that detects frost formation using a frost sensor and performs defrosting, when the output of the frost sensor does not reach the reference level within a predetermined time, defrosting is performed regardless of the output of the frost sensor. A defrosting control device characterized by comprising a timer defrosting start means for starting frosting.