JPS63307509A - Method and device for preventing dew or 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 electronic dew point/frost point meter has a calculation function that calculates the frost point based on the measured temperature and relative humidity, and a display function that digitally displays them. It will be done. The principle of its operation will be briefly explained: The relationship at phase equilibrium between liquid and gas is generally given by Kleibo's equation.

dP λ where λ is the latent heat of evaporation, '1zu2' volume in liquid or gas, and P is vapor pressure.

Assuming that λ is constant with respect to temperature and integrating equation 1), λM T P == c... -...j-...(2
). However, M: molecular weight, R: gas constant, and C: integral constant. Since equation (2) is an approximate equation, in reality, two points (p, T
Substituting s), (p, Tz) into equation (2)81
The constant c1□ is determined by s2 λM. For example (9,205,
285) (92,56,312) (unit: rMmHg)
Substituting P, :'t162X1o9 *xp (-5278/T
)"=(5), and the conversion formula for water's saturated water vapor pressure and temperature is found. The value found by equation (5) is not much different from the value of the saturated water vapor pressure found experimentally.

Next, if the relative humidity measured by the humidity detector is H and the water vapor pressure of the measurement atmosphere is P, there is a relationship between the two, so P=P, XI/100... ...(5). The measurement base - the dew point TD of the air indicates the temperature at which the water vapor pressure P of the surrounding air should become the saturated water vapor pressure at measurement 5J, so
By replacing p −+p 57-4'i' in equation (5), To=527 a/ In (P/t 162X
10') ..." (6).Equations (3), (5)
By substituting (6), TD=-s273/ln(belief n
5xp(-sz7s/T))...(7).

By equation (7), if we know the relative humidity H and temperature T, we can determine the dew point TD.
is found. TDi obtained by equation (7) has almost no error from the actual value.

By rewriting the above relational expressions (3) to (7) at a temperature equal to the saturated water vapor pressure in equilibrium with ice, H
The frost point TD is determined from the measured values of and T.

The electronic dew point/frost point meter has a built-in digital calculation processing program, and can measure relative humidity H and temperature T! 1 (frost) point TDft is calculated. Such electronic dew point/frost point meters are commercially available as dew/frost modules.

FIG. 1 is an explanatory diagram showing the structure of the base of the present invention, and FIG. 2 is a flowchart thereof. A temperature sensor 1 placed in contact with the window glass or wall surface W as a part to prevent dew condensation or frost formation, or in as much contact as possible when this is not possible, measures the surface temperature thereof. On the other hand, the dew/frost module, that is, the electronic dew point/frost point meter 3 measures the atmosphere, that is, the indoor temperature and relative humidity, using the built-in temperature sensor and humidity sensor (separate units are also possible). The 'C1M point is calculated using the formula.

A thermistor is generally used as a temperature sensor.

As the humidity sensor 5, many humidity sensing elements have been developed in recent years, and any of them can be used.
Zirconia, Ittria + Zirconia or C
A moisture-sensitive resistor, which is constructed by sintering a ceramic to which a stabilizer such as OSM is added onto a patterned electrode formed on a substrate, is excellent in terms of robustness and operational stability.

Glass surface temperature is always atmospheric dew on the glass surface (fl)
If the temperature can be maintained above the point, in principle, no condensation (frost) will occur. Therefore, in the present invention, the temperature difference (glass surface temperature - indoor air dew point) is calculated, and the calculated temperature difference is compared with a set temperature difference selected from the range of t5 to 3°C, for example. For example, if the set temperature difference is 2℃, the calculation f
The magnitude relationship between the 4 degree difference and 2 degrees Celsius is determined. When the calculated temperature difference is greater than 2°C, there is plenty of time before condensation occurs, but when the calculated temperature difference is less than 2°C, condensation is imminent.
Preventive measures must be taken promptly.

The control circuit 5 performs such comparison and determination and generates a control output.

When it is determined that the calculated temperature difference is less than or equal to a set temperature difference (for example, 2° C.), the atmospheric humidity reducing means 7, shown here as a ventilation fan, is activated. As the atmospheric humidity low range means, the optimal means for dehumidification is selected depending on the atmosphere. For example, air conditioner,
An example is a heater. The control output signal is transmitted via the operation control means 6 to drive the ventilation fan 7 when the calculated temperature difference is less than the set temperature difference, and to stop the ventilation fan 7 when the calculated temperature difference exceeds the set temperature difference. An appropriate relay circuit or the like may be used as the operation control means.

A more preferable method of driving a ventilation fan is to use two-step temperature settings. The ventilation fan is commanded to stop based on a set temperature difference (eg, 4° C.) selected from 3 to 5° C., which is higher than the above set temperature difference (eg, 2° C.). In this case, when the calculated temperature difference becomes 2° C. or less, the ventilation fan is activated, and when the calculated temperature difference becomes 4° C. or more, the ventilation fan is stopped. Ventilation fans operate until temperatures below 2°C to 4°C. By doing this,
Condensation (frost) can be prevented more stably and safely than in the case of a single temperature difference setting method.

In addition, if a large-scale building is equipped with multiple ventilation fans or ventilation fans that output multiple rotation speed levels, more fine-grained control can be achieved by setting two or more set temperature differences. I can do it.

For temperature measurement of condensation (frost) prevention areas, (I) Use of temperature module for 6 degree measurement, (n
) Dew/frost module probe switching, and (II
I) Several other schemes can be implemented. The following is an example of its configuration.

(I) Method of installing a temperature module together with the dew (11) module 8: (a) Using a microcomputer (see Figure 3 (a)) The dew point information from the dew/frost module 3 and the temperature information from the temperature module 8 are transferred to the microcomputer. 9, a microcomputer compares the two, and outputs a control output. ON by microcomputer
/OFF control bisteresis and offset can be added. Due to the use of temperature module and microcontroller,
The price will be higher.

(b) Using a logic circuit (see Figure 3(b)) Instead of the microcontroller in (a) above, use a logic IC that is cheaper.
It is composed of only 10 pieces.

Hysteresis, offset, etc. are also configured using logic ICs.

(n) I! - Switching of the probe of the frost module This is characterized by the use of a sensor switching circuit 12 as an alternative to the temperature module of (I). This is an attempt to reduce costs accordingly. An external sensor circuit for temperature measurement is connected to the dew/frost module, and the external sensor and internal sensor are switched every sample period to output dew (frost) point data and temperature data in one circuit (dew/frost module circuit). It is something to do.

(1) Using a microcomputer (see Figure 4 (1)) (I)
According to (a).

(b) Use of logic circuit (see Figure 4(b)) (I
) According to b. For example, output is taken once every 2 seconds.

This is a very practical example in terms of cost and accuracy.

(e) Use of comparator ICl3 (see Figure 4(c)) (Todoroki) This is intended to be simpler and cheaper than (b). There is no hysteresis. Adjust the offset on the probe side. Change temperature sensor probe constants. For example, when the glass window surface temperature is 25°C, it is adjusted so that it is displayed (output) as 21°C. This will bring the dew point to 21
℃, the control output is generated when the glass surface temperature is 4 degrees Celsius above the dew point.

(To) Others (a) Complete control circuit [method of including it in the mail %]
Although it is expensive, it is ideal in terms of operation and is used in applications where there is a strong need to prevent condensation (frost).

(b) Analog circuit usage method (see Figure 5) A thermometer (IC temperature sensor, etc.) using an analog circuit is used and a D-A converter 15 is used to convert the dew (frost) point data into an analog signal. , and the control output is generated by the analog converter A regulator 16. Hysteresis, offset, etc. are performed using analog circuits.

FIG. 6 shows an example of the configuration of the sensor switching circuit. The sensor 1 for measuring ambient temperature and humidity may be either an internal type or an external type. The sensor 2 is for measuring the temperature on the side of the glass window.

Example 1 As shown in Fig. 7, dew/frost module with built-in thermistor and humidity sensor (DFM-001) 5 and thermistor 1, which is a temperature sensor for the dew condensation prevention part, were used to prevent condensation in the living room of a general residence. went. The outside air was -5°C and the guide temperature was 20°C and relative humidity 60%. The external thermistor was installed on the window W. The module was placed in the living room.

Module 3 displays the dew point [12, OJ and temperature r2n, oJ of the air in the living room. In FIG. 7, P is a power source (3-1 sv). The operation of the ventilation fan 7 was controlled by the relay circuit 6.

Using a single setting method with a set temperature difference of 2°C or less and a two-step setting method with a set temperature difference of 2°C and 4°C, the effectiveness of preventing condensation was confirmed while driving and stopping the ventilation fan. No dew condensation occurred, and extremely smooth dew condensation prevention was achieved.

Example 2 An electronic dew point/frost point meter consists of an electronic circuit and a sensor in the detection section, but if the circuit system is not moisture-proof, it cannot be used stably for a long period of time in an atmosphere with a relative humidity of 80% or higher. I can't.

For this reason, a method can be considered in which a part of the circuit system and the sensor probe including the sensor of the detection section are connected to a single module circuit. FIG. 8 shows such an embodiment. russian pa vd
An external sensor syrup (moisture-proof type, 5P-001) 20 is placed inside the roof, and a dew/frost module circuit 22 is placed inside the ventilation fan 7 in association with the control circuit 5 and the relay circuit 6.

As in Example 1, suitable prevention of dew condensation was achieved. Example 1
In 2 and 2, it was optimal to use a heat exchange type ventilation fan 7 so as not to lower the room temperature.

The above example uses a residence, but as mentioned at the beginning, the present invention has many other applications. For example, in the case of a refrigerated display case, it is effective to apply the dew condensation prevention measures of the present invention because if condensation occurs, the contents become invisible. In this case, a ventilation fan, air conditioning equipment, etc. are used as the humidity reducing means. The present invention can also be used in the rear window of an automobile. In this case, a glass heat wire controller or a heater is used as the humidity reduction means.

In addition, in optical instruments such as laser measuring instruments, dew condensation may occur on lenses under the environment in which they are used. In this case, the present invention can be applied by using a hot air blower or a dehumidifier as a means for reducing atmospheric humidity. The present invention provides a method for tying (
It is equally applicable in situations where material damage, mold, etc., or malfunctions are likely to occur due to the occurrence of frost, and if the atmosphere can be controlled.

A true dew condensation (frost) prevention effect that prevents condensation II (frost) can be realized efficiently and stably without causing deterioration of the humidity sensor.

It has high accuracy, reliability, and practicality.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the basic configuration of the present invention, Fig. 2 is a flowchart thereof, Figs. 5(a) and 3(b) are explanatory diagrams of a practical example using a temperature module, Fig. 4(&), 4(b
) and 4(c) are explanatory diagrams of practical examples using sensor switching circuits, Fig. 5 is an explanatory diagram showing an example of analog system, and Fig. 6
7 shows a configuration example of the sensor switching circuit, FIG. 7 shows a configuration example related to the first embodiment, and FIG. 8 shows a configuration example related to the second embodiment. 1: Temperature sensor W: Window glass 3: Anti-frost module 5: Control circuit 6: Operation control means 7: Humidity reduction means (ventilation fan) 8: Temperature module 9: Microcomputer 10: Logic circuit 12: Senna switching circuit 13: Comparator IC 15: D-A converter 16: Analog comparator circuit 2〇2 Dew/box external sensor probe 22: Dew/frost module circuit, -1"1 Figure 1 Figure 2 Figure 3 (a) Figure 3 ( b) Figure 4(0) Figure 4(b) Figure 4(C)

Claims (1)

[Claims] 1) (a) Measuring the temperature of the dew or frost prevention area in the atmosphere and also measuring the temperature and relative humidity of the atmosphere; (b) From the measured temperature and relative humidity of the atmosphere. Calculate the dew point or frost point of the atmosphere; (c) Calculate the temperature difference by subtracting the atmosphere calculated dew point or frost point from the measured temperature of the dew or frost prevention area; (d) The calculated temperature difference indicates dew condensation. Alternatively, a method for preventing dew condensation or frost formation, which includes activating an atmospheric humidity reducing means when the temperature difference falls below a set temperature difference for frost prevention. 2) Equipped with (a) a temperature sensor placed in contact with or in close proximity to a dew or frost prevention area in the atmosphere, and (b) a temperature sensor and a humidity sensor that measure the temperature and relative humidity of the atmosphere, an electronic dew point/frost point meter having a circuit for calculating the dew point or frost point from the ambient temperature and relative humidity; a control circuit that determines the magnitude of the calculated temperature difference obtained by subtracting the difference from the set temperature difference for preventing condensation or frost; (d) atmospheric humidity reducing means; (e) reducing the atmospheric humidity according to the determination of the control circuit. and an actuation control means for controlling activation and deactivation of the dew or frost prevention device. 3) The device according to claim 2, in which a temperature sensor and a humidity sensor of an electronic dew point/frost point meter and a calculation circuit are integrated. 4) The device according to claim 2, wherein the temperature sensor and humidity sensor of the electronic dew point/frost point meter and the calculation circuit are separate bodies. 5) The device according to claim 2, wherein the control circuit includes a temperature module and a microcomputer or a logic circuit. 6) The device according to claim 2, wherein the control circuit includes a sensor switching circuit, a microcomputer, a logic circuit, or a comparator IC. 7) The device according to claim 2, wherein the temperature sensor is of an analog type and the control circuit includes a DA converter and an analog comparator circuit.