JPH0526828A - Method and device for measuring liquid water content in air - Google Patents

Abstract

PURPOSE:To measure the liquid water content in the air regardless of the diame ter of mists and, at the same time, to eliminate restriction to the installing location of a measuring device. CONSTITUTION:After the air to be measured is led into a measurement container 16 while the air is heated through a lead-in section 15 provided with a heater, the temperature and relative humidity in the container 16 are measured. An arithmetic section 14 calculates the water vapor content in the air from the measurements and finds the liquid water content in the air by subtracting the saturated water vapor content decided by the temperature of the air from the calculated water vapor content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the amount of fog water floating in a mist state due to supersaturation of water in the atmosphere.

[0002]

2. Description of the Related Art The amount of water in the atmosphere can be measured by measuring the temperature and relative humidity in the air when the amount of water contained is in the unsaturated region. However, when the amount of water contained in the atmosphere increases and the supersaturated region is reached, a liquid state called fog exists, so that the measurement of the amount of water contained is not easy. However, measuring the amount of fog water is very important to set the amount of fog water in the atmosphere to a required value, for example, when an artificial stain test is performed on an insulator by the fog method.

FIG. 4 is a perspective view showing an example of the configuration of a conventional measuring apparatus for measuring the amount of fog water in the atmosphere. A wind tunnel 2 is arranged in a measured atmosphere 1 containing fog, and two holes 3 are formed in the wind tunnel 2 to penetrate a pipe wall. A stainless wire 4 having a diameter of 200 μm is passed through the hole 3, and the wire 4 is stretched in a triangular shape by two rotating shafts 5 and pins 6.
A pin hole 7 penetrates the pin 6, and the wire 4 is passed through the pin hole 7. On the other hand, the pin 6 is arranged so that its lower end is in contact with the recording paper 8, and the pin 6 is fixed by a supporting device (not shown). The recording paper 8 can be wound in the direction of arrow B by two winding shafts 9.

In FIG. 4, the measured atmosphere 1 is sucked together with fog water in the direction of arrow C by a suction fan (not shown) in the wind tunnel 2. The sucked fog water adheres to the wire 4 in the wind tunnel 2. When the wire 4 is moved in the direction of arrow D by the rotating shaft 5 for a certain period of time, the wire 4 is squeezed by the pin hole 7 at that time, so that the fog water adhering to the wire 4 accumulates on the recording paper 8 as water droplets. The recording paper 8 is made of water blue treated paper and has the property of being dyed when water adheres to it. Reference numeral 10 in FIG. 4 denotes a dyed portion, and the area of this dyed portion 10 is proportional to the amount of fog water attached to the wire 4. The area of the dyeing unit 10 is obtained, and the proportional constant determined by the configuration of the measuring device is checked in advance by calibration, so that the amount of fog water in the measured atmosphere 1 can be converted. When performing the next measurement, the recording paper 8 is shifted in the B direction by a predetermined distance so that the lower end of the pin 6 comes to the undyed portion. By repeating this operation, the amount of fog water can be measured many times.

[0005]

However, the conventional apparatus described above has a problem that the smaller the particle size of the fog water, the worse the adhesion to the wire.

In general, a Van der Waals force due to an intermolecular attractive force works between adjacent objects, and the adhesion force of a water drop to a wire is due to this force. The larger the particle size is, the stronger the adhesive force when the water droplet contacts the wire. That is, when the water droplet contacts the wire, the water droplet itself deforms from a spherical shape to a flat shape, and the larger the particle diameter, the larger the contact area with the wire. Since the combined force of van der Waals forces acting per unit area becomes the adhesive force, the adhesive force increases as the particle size of the water droplet increases. Therefore, if the mist has a small particle size, it becomes difficult to adhere to the wire. The method of attaching mist to the wire as shown in FIG. 4 has a problem that the measured value of the amount of mist water is inevitably small in the case of an atmosphere in which mist with a small particle size exists. Further, it is necessary to bring the wind tunnel and the pin as close as possible so that the adhered state of water droplets does not change during the movement of the wire, and there is also a restriction on the installation location of the measuring device.

In addition to the wire method as shown in FIG. 4, methods for measuring airborne particles include a light scattering method and a β ray absorption method. However, in these methods, it is necessary to perform sampling with a tube-shaped one, and therefore, in the case of fog, it is likely to adhere to the tube or vaporize in the middle, and the measurement accuracy is extremely poor.

It is an object of the present invention to provide a method and apparatus for measuring the amount of fog water in the atmosphere, which enhances the measurement accuracy irrespective of the particle size of the fog and has no restriction on the place of installation.

[0009]

In order to achieve the above-mentioned object, the method according to the present invention is a method in which the atmosphere to be measured containing fog water is heated to a predetermined temperature, and the fog water contained is entirely converted to steam. To calculate the amount of water vapor in the measured atmosphere from the temperature and relative humidity in this measurement container, and subtract the saturated amount of water vapor determined by the temperature of the measured air from this amount of water vapor to determine the amount of fog in the atmosphere. Shall seek.

Further, the apparatus according to the present invention includes an atmospheric temperature sensor for detecting and outputting the temperature of the atmosphere to be measured containing fog water, an introducing portion provided with a heater for heating the atmosphere to be measured to a predetermined temperature, and A measurement container in which the measured atmosphere is introduced into the measurement unit in a state where all the fog water contained therein is changed to steam through an introduction unit, a container temperature sensor for detecting and outputting the temperature in the measurement container, and a relative humidity in the measurement container. A humidity sensor that detects and outputs the temperature sensor, a calculation unit that receives the output signals of the atmospheric temperature sensor, the container temperature sensor, and the humidity sensor, respectively, and calculates and outputs the fog water amount of the measured atmosphere, and the output of this calculation unit The calculation unit calculates the amount of water vapor in the measured atmosphere from the temperature and relative humidity in the measuring container. And it calculates a fog amount of water in the air by subtracting the saturated steam amount determined by the temperature of the air to be measured.

[0011]

According to the structure of the present invention, the atmosphere to be measured containing fog water is heated to a predetermined temperature by the introduction portion provided with the heater, and the fog water contained is entirely introduced into the measurement container in the state of being steam. The temperature and the relative humidity of the measured atmosphere introduced into the measurement container are obtained by the container temperature sensor and the humidity sensor in the measurement container. The calculation unit calculates the amount of water vapor in the measured atmosphere from the temperature and the relative humidity. Furthermore, by subtracting the saturated water vapor amount determined by the temperature of the measured atmosphere from the amount of water vapor by this calculation unit, this value is the amount that was in the fog state due to supersaturation in the space, that is, It is equivalent to the amount of fog water.

[0012]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a sectional view showing the arrangement of an apparatus for measuring the amount of fog water in the atmosphere according to the embodiment of the present invention. The temperature of the measured atmosphere 11 containing fog water is detected by the atmospheric temperature sensor 13 provided in the space 12, and the output signal 13S is sent to the arithmetic unit 14 via the amplifier 13A. Introductory part 15 is space 12
And the measurement space 16 and the introduction part 1
A pump 17 such as a diaphragm is provided in the middle of 5, and the atmosphere 11 to be measured is sucked in the direction of arrow E, sent into the measurement container 16, and exhausted from the outlet 19. Introductory part 1
5, the pump 17 and the measuring container 16 are covered with a heat insulating material 18. The measuring container 16 is provided with a container temperature sensor 20 and a humidity sensor 21, which detect the temperature and relative humidity of the sucked air, and output signals 20S and 21S to the arithmetic unit 14 via amplifiers 20A and 21A, respectively. Has been. The calculation unit 14 receives the output signals 13S, 20S and 21S and outputs the output signal 14S, and the display unit 22 receives the output signal 14S and displays it on a time chart or the like.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 and is an enlarged sectional view showing the structure of the introducing portion 15. A heater 24 connected to lead wires 25 and 26 via an insulator 27 is arranged on the outer wall surface of a metal tube 23 that sends the measured atmosphere 11. The outermost periphery is covered with a heat insulating material 18. Lead wire 25, 2
6 are arranged side by side in the longitudinal direction of the introducing portion 15, and a current is supplied to the heater 24 in the circumferential direction of the introducing portion 15 by supplying power from both. The heater 24, the insulator 27, and the lead wires 25, 26 are generally sold as a unit as a unit, for example, under the trade name of "auto trace" from Raychem, USA. The heater 24 is a mixture of polymer and conductive particles, and has a self-temperature controllability.
That is, the heater 24 has a function of increasing its resistance value and lowering the temperature when the temperature rises, and decreasing the resistance value and raising the temperature when the temperature lowers. Therefore, the metal tube 2
The temperature can be kept uniform at any position in the longitudinal direction of No. 3. The metal tube 23 is made of stainless steel and has an outer diameter of 8 mm,
A polyurethane foam tube is used as the heat insulating material 18.

Returning to FIG. 1, the air to be measured 11 is heated to a predetermined temperature (above the temperature at which all the fog water contained therein becomes steam) by the introduction part 15 and sent into the measuring container 16. As described above, the measured atmosphere 11 is generated by the heater 24 shown in FIG.
Since the temperature is set to a predetermined constant temperature, the introduction part 15 and the pump 1
7. No condensation occurs in the measurement container 16. The calculation unit 14 calculates the amount of water vapor in the measured atmosphere 11 from the temperature and relative humidity in the measurement container 16, and the space 1 is calculated from this amount of water vapor.
The amount of fog water in the space 12 can be obtained by subtracting the amount of saturated steam determined by the temperature of 2.

Next, a method of calculating the amount of fog water in the calculation unit 14 of FIG. 1 will be described. Space 12, measuring container 1
6 and T ₁ and T ₂ [° K], respectively, and measuring container 16
The relative humidity inside is set to H _R [%], and these values are detected by each sensor. Letting Y ₁ and Y ₂ be the saturated water vapor amount [kg / m ³ ] of each of the space 12 and the measurement container 16 (maximum water vapor density that can exist as water vapor at that temperature), Y _i = X _i /{0.004555 ( X _i +0.662) T _i } (1) Here, i = 1 or 2, and X _i = 0.622 P (T _i ) / {760 −P (T _i )} (2)

[0016]

[Equation 1]

P (T _i ) in the equation (3) is a saturated vapor pressure curve at the temperature T _i expressed by an approximate equation, and the error is + 3% in the range of 0 ° C to 70 ° C. To -1.
Within 7%. Thus, the fog amount of water F (kg / m ³⁾ per unit volume in the space 12 becomes _{F = Y 2 · (H R} / 100) -Y 1 ...... (4). That is, the first term of the equation (4) corresponds to the water vapor density (absolute humidity H _A ) actually existing in the measurement container 16,
Water content per unit volume actually existing in the space 12
Is equal to (sum of steam and fog). Therefore, if the saturated water vapor amount Y ₁ of the space 12 is subtracted from the absolute humidity H _A , the fog water amount F in the space 12 is obtained, and it is possible to perform measurement without leaking even if the particle diameter of the fog is small. Further, since the sensor in the space 12 is only the atmospheric temperature sensor 13, and the introduction part 15 can be stretched by 10 m or more in the longitudinal direction, there is no restriction on the installation place of the measuring device.

FIG. 3 is a characteristic diagram showing the actual measurement results by the fog water amount measuring device of FIG. The horizontal axis shows time t, and the vertical axis shows temperature, absolute humidity or amount of fog water. Outer diameter 8mm,
The atmosphere 15 to be measured is kept at 40 ° C. to 60 ° C. by the introduction part 15 made of a metal tube 23 made of stainless steel having a length of 10 m
The time change of the fog water amount F when the space 12 was heated to (= T ₂ ) and the fog was sprayed to the space 12 was obtained. Spraying was started at time t ₁ and stopped at time t ₂ . The characteristic curve 28 is the temperature T _{1 of the} space 12, the characteristic curve 29 is the absolute humidity H _A of the measured atmosphere 11, and the characteristic curve 30 is the fog water amount F of the space 12. The amount of fog water or the absolute humidity becomes negative in a state where the fog water does not exist in the space 12, indicating that the water vapor is unsaturated. The conventional measuring device shown in FIG. 4 is not able to determine the amount of water vapor when it is unsaturated, while the device according to the present invention has the advantage that it can also determine the water vapor density when it is unsaturated.

[0019]

As described above, according to the method of the present invention, the atmosphere to be measured is heated by the introduction part provided with the heater and guided to the measurement container. The temperature and relative humidity of the measuring container and the space temperature of the measured atmosphere were measured, and the amount of fog water in the space was calculated by the calculation unit from these measured values. By this method, it is possible to measure the fog in the measured atmosphere including all those having a small particle size, and it is possible to improve the measurement accuracy.

Further, since the atmospheric temperature sensor is installed in the space and the measurement can be performed at a distance of 10 m or more from the space through the introduction part, there is no restriction on the installation place of the measuring device.

Furthermore, since the amount of water vapor in the space where the water vapor is unsaturated can also be determined, the fog water amount measuring device according to this method can also be used as an absolute hygrometer, and a measuring device having a wide measuring range can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of a fog water amount measuring device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a characteristic diagram showing measurement results obtained by the fog water amount measuring device of FIG.

FIG. 4 is a perspective view showing a configuration example of a conventional fog water amount measuring device.

[Explanation of symbols]

11 Measured atmosphere 12 spaces 13 Air temperature sensor 14 Operation part 13A amplifier 20A amplifier 21A amplifier 15 Introduction 16 measuring vessels 17 pumps 18 Insulation 19 exit 20 Container temperature sensor 21 Humidity sensor 22 Display 23 Metal tube 24 heater 25 lead wire 26 Lead wire 27 Insulator

Claims (2)

[Claims] 1. The atmosphere to be measured containing fog water is heated to a predetermined temperature, and the fog water is introduced into a measuring container in a state where all of the fog water is converted into water vapor. A method for measuring the amount of fog water in the atmosphere, the method comprising: calculating the amount of water vapor in the atmosphere and subtracting the amount of saturated water vapor determined by the temperature of the atmosphere to be measured from the amount of water vapor to obtain the amount of fog water in the atmosphere. 2. An atmospheric temperature sensor for detecting and outputting the temperature of the atmosphere to be measured containing fog water, an introducing portion provided with a heater for heating the atmosphere to be measured to a predetermined temperature, and the object to be measured through this introducing portion. A measuring container that is introduced in a state where the atmosphere contains all of the fog water contained in water vapor, a container temperature sensor that detects and outputs the temperature inside the measuring container, and a relative humidity inside the measuring container that is detected and output. A humidity sensor, a calculation unit that receives the output signals of the atmospheric temperature sensor, the container temperature sensor, and the humidity sensor, and calculates and outputs the amount of fog water in the measured atmosphere, and the measured atmosphere that receives the output signal of this calculation unit And a display unit that displays the amount of fog water, the calculation unit calculates the amount of water vapor in the measurement atmosphere from the temperature and relative humidity in the measurement container, and from the amount of water vapor the temperature of the measurement atmosphere Apparatus for measuring the fog amount of water in the atmosphere, characterized by calculating the fog amount of water in the air by subtracting the full saturation water vapor content.