JPH03202749A - Target-frost-point generating apparatus - Google Patents

Abstract

PURPOSE:To generate a target frost point in a short time by judging whether water is completely frozen or not based on the changing rate of the temperature of the water in cooling, and controlling the temperature of ice after perfect icing is confirmed so that the target frost point is obtained. CONSTITUTION:The temperature of water W in a container 1 is lowered by a cooler 3. When the temperature becomes a freezing point or below, freezing is started. During the period wherein the water W is cooled and freezed, a microcomputer 61 computes the changing rate of the temperature based on the output of a temperature detecting end 5. When the rate of change reaches a predetermined range, it is judged that the water W is completely frozen. Thereafter, the operating amount of an electric heater 4 is computed so that the temperature of the ice becomes a target frost point in the microcomputer 61 based on the difference between the present ice temperature based on the output of the detecting end 5 and the target frost point that is set at a target- frost point setting part 62. The ice temperature can be brought to the target frost point quickly by operating the heater with an operating part 63 based on the operating amount.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a target frost point generating device for obtaining an atmosphere adjusted to a predetermined frost point in an environmental testing device or the like.

[Conventional technology]

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

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

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

[Problem to be solved by the invention]

However, according to this conventional method, even if the water is actually completely frozen, it is not possible to control the ice temperature to the target frost point until the initially predicted complete freezing temperature is reached. , it took that long to obtain air with the desired frost point.

Further, when setting the expected complete freezing temperature to be high in order to shorten this time, there is a fear that frost point control may be started without complete 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 conventional methods.

[Means to solve the problem]

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

[Function] According to the device of the present invention, the water contained in the container to obtain the target frost point is cooled by the cooling means while lowering the temperature to below the freezing point, and the rate of change in water temperature is sequentially measured during this cooling. , when the rate of change indicates that a complete freezing state has been entered, the ice temperature is controlled toward the target frost point, and the target frost point is finally obtained. By bringing air into contact with this water surface, air adjusted to the target frost point can be provided.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of an embodiment.

The embodiment shown in FIG. 1 includes a container 1 containing water W for obtaining a target frost point, a cooler 3 disposed inside the container, an electric heater 4 for temperature control, a temperature detection end 5, and a A regulator 6 is provided.

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

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

Incidentally, a flexible pipe 7 is provided above the container 1 and is open to the container side, and supplies dry air taken in from the lower flexible pipe 1 into the test chamber 8 of the environmental test apparatus.

The cooler 3 corresponds to an evaporator of a refrigeration system, not shown in its entirety, and has the ability to cool the water W to the lowest target frost point.

According to the above embodiment, the water W in the container 1 is cooled by the operation of the cooler 3, and its temperature gradually decreases, and as shown in FIG. Freezing begins and then completes freezing.

While the water W is being cooled and frozen in this way, the microcomputer 61 of the regulator 6 calculates the rate of change in 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 It is determined that the temperature has completely frozen, and after that, the temperature detection end 5
The operation amount of the electric heater 4 is calculated 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 so that the ice temperature moves toward the target frost point, and the operation unit 63 adjusts the operation amount to this operation amount. The heater 4 is operated based on this. The ice temperature thus quickly reaches the target frost point.

When the dry air taken into the corrugated tube 7 passes through the corrugated tube 7, it comes into sufficient contact with the ice surface whose frost point is controlled, and thus air adjusted to the target frost point is provided to the test chamber 8.

The determination of complete freezing of water W based on the rate of change in temperature is based on the rate of change of temperature.
This can be determined by detecting a large rate of temperature change from the start of cooling until freezing begins, followed by a slow rate of temperature change from the start of freezing to the completion of freezing, followed by a large rate of temperature change again. In this example, it is determined that freezing is complete when a predetermined large rate of temperature change occurs after the gradual rate of temperature change from the start of freezing to the completion of freezing.

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

Next, the operation of the microcomputer 61 will be explained based on the flowchart shown in FIG.

First, in step S1, initial settings such as setting the freezing flag F to O are performed. Next, in step S2, a target frost point is input based on the operation of the target frost point setting section 62. In step S3, the temperature of the water W is measured, and in step S4, it is determined whether or not the freezing flag F is set to 1.
If not, the process advances to step S5, where the water W is
The rate of change in temperature of water W is determined, and further in step S6
It is determined whether or not the ice has completely frozen. If complete freezing has not yet occurred, 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 temperature is set to the set frost point based on the set frost point and the temperature of the water W. The operating amount of the heater 5 is calculated, and the operating amount is instructed to the operating unit 63 in step Sll. The operation unit 63 operates the heater 4 to move toward the set frost point based on this operation amount.

After step 5llO, the process returns to step S3 again.

In this way, before the water W completely freezes, steps S3 and S
4, repeat S5, S6, S9, SIO and 311.

When it is determined that the water W has completely frozen in step S6 after steps 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. Set it again. Next, the operating amount of the heater 4 is calculated from the target frost point and ice W temperature set in step SIO, and the operating amount is instructed to the operating unit 63 in step Sll. The operation unit 63 operates the heater 4 based on this operation amount so that the ice temperature moves toward the target frost point. After step 5llO, the process returns to step S3 again. In this way, after complete freezing is confirmed in step S6, steps S3, S4, SIO, and Sll are repeated.

FIG. 4 shows another embodiment of the invention. According to this embodiment, a container 1 containing water W is surrounded by a jacket 9 containing brine B, and a watertight casing 2 containing a cooler 3 and a temperature control heater 4 is arranged within this jacket.

In other respects, the configuration is the same as that of the embodiment shown in FIG.

FIG. 5 shows still another embodiment, in which the container 10 containing water W is box-shaped and has a larger volume than that containing the water W, and the space 101 above the water W is This can be used as a test chamber for environmental testing equipment, and the other configurations are the same as the embodiment shown in FIG.

Note that the present invention is not limited to the above embodiments,
It can also be implemented in various other ways.

For example, in the embodiment described above, the ice temperature is controlled by operating the heater 4, but instead of controlling the ice temperature by operating the cooler 3.
The amount of refrigerant circulated to the cooler may be controlled by adjusting the opening degree of an expansion valve (not shown) in the refrigeration system including the cooler.

In this case, the operating section 63 is an operating section that can control the opening degree of the expansion valve.

Note that such an expansion valve whose opening degree can be adjusted may be an electronic expansion valve whose opening degree can be adjusted by a stepping motor.

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

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to provide a device that can generate a target frost point in a shorter time than conventional devices.

[Brief explanation of 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 the target frost point generator shown in Fig. 1, and Fig. 3 is similar to Fig. 1. FIG. 4 is a schematic block diagram of another embodiment of the present invention, and FIG. 5 is a schematic block diagram of still another embodiment of the present invention. ■, 10...Container 3...Cooler...Electric heater...Temperature detection end...Adjuster 1...Microcomputer 2...Target frost point setting section 3...Heater operation Department

Claims (1)

[Claims] (1) a container containing water for generating a target frost point, a means for cooling the water in the container below the freezing point, and a means for determining the rate of change in the water temperature during cooling by the cooling means;
A target frost comprising means for determining whether the water has completely frozen based on the rate of change, and means for controlling the ice temperature to obtain a target frost point after confirming complete freezing of the water based on the rate of change. Point generator.