JPS6015859B2 - Cooler defrost device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a defrosting device for freezing and refrigeration equipment, and more particularly to a device for detecting the amount of frost on freezing and refrigeration equipment using a simple method and performing efficient defrosting.

Conventionally, the time to defrost a cooler of a freezing or refrigeration device has been determined by a timer device based on a predetermined cumulative time since the end of the previous defrost.

Since the predetermined cumulative time using this method is generally determined based on the operating conditions that cause the most frost, defrosting is performed even when there is little frost on the food and there is no need to defrost, which is a problem in terms of product overflow management and energy saving. There were many inconveniences from this point of view. In recent years, this method has been improved and is now widely used in household refrigerators, etc., by calculating the cumulative operating time of the refrigerator, that is, the closing time of the thermostat inside the refrigerator, and defrosting when the cumulative operating time of the refrigerator reaches a predetermined value. There is a defrosting control method that starts.

This method has an automatic function that defrosts according to the load of the cooler, that is, when the load is 4.5 cm, the defrost interval becomes longer, and when the load is large, the defrost interval becomes shorter. Although it is simple and ingenious in that it does not require any accessory equipment such as a temperature detection mechanism, it has the following drawbacks.
First of all, the amount of mist deposited is not proportional to the load on the cooler. For example, if the thermostat in the refrigerator is closed most of the time, that is, if the cooler is large in number, the refrigerator is in continuous operation, and the head heat ratio of the refrigerator load is very large, the thermostat In a defrosting control device that operates by integrating the closing time, a complicated defrosting operation is performed even though the amount of frost on the heat transfer surface of the cooler is very small. Although this example is a very extreme case, the actual heat ratio of the heat removed by the cooler is not constant depending on the conditions, but is influenced by the temperature of the cooler, the air condition at the cooler inlet, etc. In other words, the cumulative start time of defrost by the defrost controller based on the cumulative closing time of the thermostat is determined by the appropriate defrost cycle when the ambient conditions are high such as in the summer and the refrigerator is at continuous or maximum operating rate. , the amount of frost on cooling during that cumulative time is the limit value for efficient operation of the equipment. However, when ambient conditions drop, such as in winter, the sensible heat ratio of the amount of heat removed by the cooler naturally increases, and even for the same cumulative time, the amount of frost on the cooler is small, meaning that it is better to start defrosting earlier. The time to start defrosting cannot be selected using this method.
Furthermore, when the operating rate of the refrigerator decreases, the frost on the cooler naturally partially melts, the density of the frost increases, and the thickness of the frost layer decreases, making it possible to lengthen the defrosting interval. The biggest problem is that the cumulative time set on the timer device is designed assuming the worst case scenario, and in reality, the defrosting frequency may be higher than necessary. be.

The present invention has been made to improve the various drawbacks of the conventional examples described above, and the defrosting of the cooler is started by the logical product of the temperature of the object to be cooled and the cumulative ON time of the temperature detector that drives the refrigerator. It's up to you to decide.

The details of the present invention will be explained below according to the illustrated embodiments.

FIG. 1 is a block diagram of a control circuit in which the present invention is applied to an operation control device for freezing and refrigeration equipment. In this figure, 1 is a first temperature detection device that detects the refrigerator room temperature; A refrigerator 4 serving as a cooling means is driven and stopped through an adjustment circuit 2 and a gate 3. 5 is a timer device that integrates the output time of the ON signal from the temperature control circuit 2, and outputs a signal to the gate circuit 6 at a predetermined integrated time.

A second temperature detection device 7 detects the temperature of the object to be cooled stored in the refrigerator compartment and inputs the detected temperature to the control circuit 8.

The control circuit 8 outputs a signal to the gate circuit 6 when the output of the second temperature detection device 7 exceeds a predetermined temperature. The gate circuit 6 receives the signal from the timer device 5, and
If there is a signal from the control circuit 8, the signal is output and the defrosting device 9 is driven. At this time, the output from the gate circuit 6 is also input to the gate 3, and the operation of the refrigerator 4 is stopped. For those configured as above,
The defrosting device 9 is activated only when there is an output from the timer device 5 and an output from the control circuit 8, that is, when the accumulated operating time of the refrigerator 4 is at least a predetermined value and the temperature of the object to be cooled is at least the set value. Therefore, if the temperature of the object to be cooled, that is, the temperature of the refrigerator compartment, is sufficiently low and defrosting is not necessary, defrosting will not be performed even if the cumulative operating time of the refrigerator 4 is greater than a predetermined value. It turns out.

The temperature of the object to be cooled changes more slowly than the temperature of the refrigerator or the temperature difference between the inflow and outflow air of the cooler, so if this temperature exceeds the set value, it is certain that the cooler has frosted. This increases reliability against changes in the operation of the refrigeration cycle compared to detecting the temperature of the refrigerator compartment or the temperature difference between the air flowing in and out of the cooler.

As described above, according to the present invention, defrosting is started based on the logical product of the cumulative operation time of the refrigerator and the temperature of the object to be cooled. Optimum defrosting control is possible in that the operation is carried out, and practical effects such as power saving and prevention of temperature rise inside the refrigerator can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the defrosting device of the present invention. The same reference numerals in the figures indicate the same or equivalent parts, 1 is the first temperature detection device, 4 is the refrigerator, 5 is the timer device, 6 is the gate circuit, 7 is the second temperature detection device, and 9 is the defrosting device. It is. Figure 1

Claims (1)

[Claims] 1. A first temperature detection device that detects the room temperature of the object to be cooled and outputs a signal for controlling on/off of the refrigerator, a second temperature detection device that detects the temperature of the object to be cooled, and the first temperature detection device. a timer device for accumulating the on-signal output time from the device; a defrosting device for removing frost attached to the cooled chamber and the cooler to be cooled; A defrosting device for a cooler, comprising: a gate circuit that starts the operation of the defrosting device when the output from the temperature detecting device exceeds a predetermined value.