JP2786705B2 - Target frost point generator - Google Patents

Description

The present invention relates to a target frost point generator for obtaining an atmosphere adjusted to a predetermined frost point in an environmental test device or the like.

[Conventional technology]

In an environmental test device or the like, in order to obtain an atmosphere adjusted to a predetermined frost point, usually, water is cooled to a temperature below the freezing point and frozen, and the temperature of the obtained ice is controlled toward the target frost point, Air is brought into contact with the ice.

However, even if the water is below the freezing point, there are two states: a supercooled water state (liquid) and a frozen state (solid).
In this case, there is a difference in the saturated steam pressure coexisting with the water or ice depending on these two states, and there is a difference in the amount of water contained in the gas even at the same temperature.

Therefore, to treat it as a frost point below freezing,
Areas in contact with gas must be frozen. For this reason, conventionally, the temperature of the ice is allowed to reach a temperature at which the water is expected to completely freeze, and then the ice is controlled to a desired frost point.

[Problems to be solved by the invention]

However, according to this conventional method, even if the water is actually completely frozen, the temperature of the ice cannot be controlled to the target frost point until the initial expected complete freezing temperature is reached. It took time to obtain air with the target frost point.

In addition, when the predicted complete freezing temperature is set to be higher to shorten this time, there is a risk that the frost point control may be started while completely freezing.

Therefore, an object of the present invention is to provide an apparatus that can generate a target frost point in a shorter time than in the related art.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention provides a container for containing water for generating a target frost point, means for cooling water in the container to a temperature below freezing, and a rate of change of the water temperature during cooling by the cooling means. Means for determining whether the water is completely frozen from the rate of change, and means for controlling the ice temperature to obtain a target frost point after confirming the complete freezing of the water based on the rate of change. It is intended to provide a target frost point generating device provided with:

(Operation)

According to the apparatus of the present invention, the water for obtaining the target frost point accommodated in the container is cooled while cooling down to a temperature below the freezing point by the cooling means, and the rate of change of the water temperature is measured successively during this cooling, Indicates that the ice has entered a completely frozen state, the ice temperature is controlled to the target frost point, and the target frost point is finally obtained. By bringing the air into contact with the ice surface, air adjusted to the target frost point can be provided.

[Example]

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

 FIG. 1 shows a schematic configuration of one embodiment.

In the embodiment shown in FIG. 1, a container 1 for storing water W for obtaining a target frost point, a cooler 3, a temperature control electric heater 4, a temperature detecting end 5, and a container And an adjuster 6.

The cooler 3 and the electric heater 4 are surrounded by the watertight casing 2.

The controller 6 is a microcomputer 61 (hereinafter referred to as “microcomputer”).
61 "), to which a target frost point setting unit 62 and an operation unit 63 of the electric heater 4 are connected. The output of the temperature detection terminal 5 is input to the microcomputer 61, and the operation unit 63 is connected to the heater 4 by wiring.

In addition, on the container 1, a flexible tube 7 opened to the container side is provided, and the dry air taken in from the flexible tube inlet 71 is supplied into the test chamber 8 of the environmental test apparatus.

The cooler 3 corresponds to an evaporator of a refrigerating apparatus (not shown) and has a capability of cooling the water W to a minimum target frost point.

According to the embodiment, the water W in the container 1 is cooled by the operation of the cooler 3 and gradually decreases in temperature. When the temperature falls below the freezing point (0 ° C.) as shown in FIG. Freeze begins and then freezes.

While the water W is cooled and frozen as described above, the microcomputer 61 of the controller 6 calculates the rate of change of the temperature based on the output from the temperature detection terminal 5, and when the rate of change falls within a predetermined range, the water W Is determined to be completely frozen, and then the temperature detector 5
From the difference between the current ice temperature based on the output from the controller and the target frost point set in the setting unit 62, the operation amount of the electric heater 4 is calculated so that the ice temperature goes to the target frost point. The heater 4 is operated based on the operation. Thus, the ice temperature quickly reaches the target frost point.

When the dry air taken into the flexible pipe 7 passes through the flexible pipe 7, the dry air sufficiently contacts the ice surface controlled at the frost point, and the air adjusted to the target frost point is provided to the test chamber 8.

The determination of complete icing of the water W based on the rate of change of the temperature is made after a large rate of temperature change from the time when the water W starts to be cooled to the time when icing is started, after a gradual temperature change from the start of icing to the completion of icing. The determination can be made by catching the large rate of change in temperature. In this example, the completion of freezing is determined when a predetermined large rate of change in temperature appears after the gentle rate of change in temperature from the start of freezing to the completion of freezing.

The line indicated by a two-dot chain line in the graph of FIG. 2 is based on the conventional method, and indicates that after reaching a predetermined expected freezing temperature, the ice temperature is controlled toward the target frost point. As can be seen from the graph, the target apparatus can reach the target frost point more quickly than in the conventional method.

Next, the operation of the microcomputer 61 will be described with reference to the flowchart shown in FIG.

First, in step S1, initialization such as setting the icing flag F to 0 is performed. Next, in step S2, the target frost point setting unit 62
The target frost point is input based on the operation of. In step S3, the temperature of the water W is measured. In step S4, it is determined whether or not the icing flag F is set to 1. If not, the process proceeds to step S5, where the temperature of the water W changes. The rate is obtained, and it is determined in step S6 whether the water W is completely frozen. If complete icing has not yet been performed, the frost point is set to a predetermined frost point lower than the target in step S9, and then the process proceeds to step S10, where the frost point moves from the set frost point and the temperature of the water W to the set frost point. Then, the operation amount of the heater 5 is calculated, and the operation amount is instructed to the operation unit 63 in step S11.
The operation unit 63 operates the heater 4 to the set frost point based on the operation amount.

After step S11, the process returns to step S3. Before the water W completely freezes, steps S3, S4, S5, S6,
S9, S10 and S11 are repeated.

If it is determined in step S6 that the water W has completely frozen in step S6 after step S3, S4 and S5, the freezing flag F is set to 1 in step S7, and the frost point is set to the target frost point in step S8. Reset to. Then step
The operation amount of the heater 4 is calculated from the target frost point and the ice W temperature set in S10, and the operation amount is instructed to the operation unit 63 in step S11. The operation unit 63 operates the heater 4 based on the operation amount so that the ice temperature goes to the target frost point. After step S11, the process returns to step S3. Thus one end step S6
After complete icing is confirmed in step S3, S4, S1
0 and S11 are repeated.

FIG. 4 shows another embodiment of the present invention. According to this embodiment, the container 1 for containing the water W is bent around the jacket 9 containing the brine B, and the watertight casing 2 containing the cooler 3 and the heater 4 for temperature control is arranged in this jacket. . The other points are the same as those of the embodiment shown in FIG.

FIG. 5 shows still another embodiment. In this embodiment, the container 10 for holding the water W has a box shape having a larger volume than that for containing the water W, and a space above the water W is provided.
101 can be used as a test room of the environmental test apparatus, and the other configuration is the same as that of the embodiment shown in FIG.

It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented in various other modes.

For example, in the above embodiment, the ice temperature is controlled by the operation of the heater 4. However, instead of this, the amount of refrigerant circulating to the cooler 3 is controlled by an expansion valve (not shown) in a refrigerating apparatus including the cooler. May be controlled by adjusting the opening degree. In this case, the operation unit 63 is an operation unit that can operate the expansion valve opening. An electronic expansion valve whose opening can be adjusted by a stepping motor can be considered as such an expansion valve whose opening can be adjusted.

It is also conceivable to combine the method of adjusting the opening degree of the expansion valve with the method of operating the heater in the above embodiment.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide an apparatus capable of generating a target frost point in a shorter time than in the related art.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of the present invention, FIG. 2 is a graph showing temperature changes of water and ice by a target frost point generator shown in FIG. 1, and FIG. FIG. 4 is a flowchart showing the operation of the microcomputer in the controller shown, FIG. 4 is a schematic configuration diagram of another embodiment of the present invention, and FIG. 5 is a schematic configuration diagram of still another embodiment of the present invention. 1, 10 Container 3 Cooler 4 Electric heater 5 Temperature detector 6 Controller 61 Microcomputer 62 Target frost point setting unit 63 Heater operation unit

Claims (1)

(57) [Claims] 1. A container for containing water for generating a target frost point, means for cooling the water in the container below the freezing point, means for determining a rate of change of the water temperature during cooling by the cooling means, A target frost comprising: means for determining whether or not the water has completely frozen from the rate of change; and means for controlling the ice temperature to obtain a target frost point after confirming the complete freezing of the water based on the rate of change. Point generator.