JPS60273A - Detector for frost - 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 U relates to a frost detection device that optically detects frost adhering to an evaporator of a refrigerator or the like.

Generally, removing frost from the evaporator of refrigerators and other freezers is done by
It defrosts the air at regular intervals based on the cumulative operating time of the compressor. However, the amount of frost on the evaporator of the refrigerator 111' etc. depends on the outside temperature and humidity of the refrigerator itself, as well as the opening and closing of the refrigerator door! It depends largely on the contents stored in the refrigerator, and the method described above will not remove it in case of emergency.
However, there were drawbacks such as defrosting not being carried out properly despite the low refrigerating capacity of the evaporator.

Therefore, in order to eliminate this drawback, it has been considered to install an optical detector between the fins as a means of directly detecting all the silk deposits, but since the fin spacing is extremely narrow, the entire detector is very small. When using a semiconductor element as a size detector, the temperature of the evaporator body drops to -40°C during cooling operation and reaches 60°C during defrosting, which is a severe temperature difference condition. Currently, it has not been put into practical use in reeds due to problems such as the requirement for severe cold resistance and thermal shock resistance.

The present invention aims to eliminate such drawbacks, and one embodiment thereof will be described below with reference to the accompanying drawings.

In Fig. 1, 1 is an evaporator of a refrigerator or other freezer;
2 is a pipe through which the refrigerant passes; 3 is a fin plate disposed perpendicular to the pipe; 4 is a frost detection hole provided in the fin plate; This is a frost detector having a light transmitting body provided for transmitting and receiving light, and issues a defrosting command by detecting a change in the amount of passing light due to progress of frost formation in the frost detection hole 4.

That is, the frost detector 5 will be explained in further detail in FIGS. 2 and 3. The frost detector 5 includes an optical transmitting/receiving section 6 that transmits and receives light.
and an optical transmission section 7 that transmits the light from this optical transmission/reception section. The light transmitting/receiving section 6 has a light source 8 such as a lamp on the light emitting side and a light receiving element 9 such as a cadmium sulfide photocell on the light receiving side. Alternatively, there is a method of using a semiconductor element such as a light emitting diode or a phototransistor for emitting and receiving light. The light transmitting section 7 is made of transparent resin, and the light transmitting body 10 on the light emitting side and the light transmitting body 11 on the light receiving side are arranged in parallel. By cutting both ends of the optical transmission part Y at 45 degrees as shown in the figure, the light 12 transmitted through the optical transmission part 7 enters the cut surface 13 at 45 degrees within the transmission part and is reflected at the same 45 degrees. Therefore, the light emitting section 14 of the light emitting side optical transmission body 10
In this case, since the light is transmitted to the outside of the optical transmission section orthogonally to the optical transmission section 7, the light enters the optical transmission section 7 at right angles to the light receiving section 15 of the light receiving side optical transmission body 11, and the cutting Face 13
After being reflected, the light travels through the light transmission section γ and reaches the light receiving element 9.

In order to prevent the leakage of light from the light transmitting section 7 other than the light emitting section 14 and the light receiving section 15 and ensuring the reflection on the cutting surface 13, Part 1
It is effective to fully evaporate aluminum or the like over the entire optical transmission group, leaving only the light transmitting section 5. By making the length of the optical transmitting section 7 sufficiently long, the light source 8 and the light receiving element 9 can be separated from the evaporator 1. Since it can be installed at any location, problems such as cold resistance and thermal shock resistance are solved. In fact, the optical transmitting section 7 and the optical transmitting/receiving section 6 can be made sufficiently small so that they can operate in extremely narrow spaces such as between the fins of an evaporator. Since the areas of the light emitting section 14 and the light receiving section 15, which transmit and receive light, are small, it is possible to narrow down the optical axis, and the scattering of light can also be minimized, so that frosting is always stable and very reliable. can be detected.

As is clear from the above explanation, the frost detection device of the present invention is
A pair of optical transmission bodies is arranged opposite to the frost detection hole provided in the evaporator, and the tip of the optical transmission body is cut so that the side opposite to the detection hole is tapered, and the optical transmission body is Since the light emitting source and light receiving source are placed at the rear end, the light emitting and light receiving sources can be protected from cold and heat, and the optical transmitter and each of the above sources can be miniaturized and the light beam can be made thinner, allowing for more accurate landing. It has an excellent effect of detecting frost and defrosting it.

[Brief explanation of drawings]

FIG. 1 is a plan view of a part of a freezing chamber equipped with a frost detection device N according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the device, and FIG. 3 is a plan view illustrating the operation of the device. . 4. Frost detection hole, 10, 11... optical transmission body, 8. light emitting source, 9 light receiving element (light receiving source). Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 3

Claims (1)

[Claims] A pair of optical transmission bodies are arranged opposite to the frost detection holes provided in the evaporator, and the tips of the optical transmission bodies are cut so that the side opposite to the detection holes is tapered, and the rear end of the optical transmission bodies is A frost detection device characterized in that a light-emitting source and a light-receiving source are respectively arranged in the respective parts.