CN103134914A - Microclimate instrument for measuring fabric moisture resistance and method thereof - Google Patents

Abstract

The invention relates to a microclimate meter and a method thereof for measuring the moisture resistance of fabrics. The microclimate meter includes a heating disc and a vertical water supply pipe. A sweating simulated skin is arranged above the heating disc, and the fabric to be tested is suspended in a heat preservation cover. On the cylinder and the support cross, the microclimate zone is between the simulated skin and the tested fabric. The vertical water supply pipe feeds water into the water-filled area between the heating disc and the simulated skin; an electric heating wire for heating is arranged under the heating disc; a first temperature sensor is provided on the surface of the sweating simulated skin, and the lower surface of the tested fabric A second temperature sensor and a humidity sensor are provided. The method is to calculate the moisture resistance of the fabric and the air layer above it by subtracting the moisture resistance of the air layer above it based on the measured sweat rate of the fabric, the temperature and relative humidity of the lower surface of the fabric and the temperature and humidity of the environment after the system reaches a steady state. The moisture resistance is the moisture resistance of the fabric. The invention can well measure the moisture resistance of pure moisture passing through the fabric.

Description

A kind of microclimate instrument and method for measuring fabric moisture resistance

technical field

The invention relates to the technical field of clothing measurement heat and humidity comfort testing, in particular to a microclimate meter and a method thereof for measuring the moisture resistance of fabrics.

Background technique

The main feature of the fabric made of fiber material as the main material of clothing is to have good moisture permeability. Measuring the moisture permeability of fabrics involves skin sweating simulation technology. At present, the sweating hot plate instrument proposed by the German Hohenstein Laboratory (skin model) and later became the international standard ISO11092 is basically used to measure the moisture resistance of fabrics. However, this The perspiration flat panel can not directly measure the sweat evaporation effectively through the fabric, but can only indirectly measure the power consumed by sweat vaporization. Two-step method (first measure the dry heat loss in the non-sweating state, and then measure the moisture heat loss in the sweating state) to measure the moisture resistance of the fabric. On the other hand, since the fabric under test is in direct contact with the sweating film, liquid water is more or less soaked into the fabric, thus adversely affecting the measurement results.

Contents of the invention

The technical problem to be solved by the present invention is to provide a microclimate meter and method for measuring the moisture resistance of fabrics, which can directly measure the amount of evaporated water passing through the fabrics, and at the same time avoid the problem of liquid water immersing into the fabrics and affecting the measurement results.

The technical solution adopted by the present invention to solve the technical problem is to provide a microclimate meter for measuring the moisture resistance of fabrics, which includes a heating disc and a vertical water supply pipe. A sweating simulated skin is arranged above the heating disc. The vertical water supply pipe passes water into the water-filled area between the heating disc and the simulated skin; the tested fabric is suspended above the sweating simulated skin, and an electric heating wire for heating is arranged under the heating disc. The surface of the simulated sweating skin is provided with a first temperature sensor, and the lower surface of the tested fabric is provided with a second temperature sensor and a humidity sensor; the first temperature sensor, the second temperature sensor and the humidity sensor are all connected to the The measurement and control system is connected, and the measurement and control system is used to control the heating of the electric heating wire.

The heating disc is provided with a thermal insulation cover, and the tested fabric is suspended above the sweating simulated skin through the thermal thermal cover and the supporting cross.

The sweat-simulating skin is arched and adopts a closed and isolated air layer technology.

The sweating simulated skin is a PTFE microporous membrane composite fabric.

The technical solution adopted by the present invention to solve the technical problem is: provide a method for using the above-mentioned microclimate meter for measuring the moisture resistance of fabrics, comprising the following steps:

(1) Use electric heating wire to heat, so that the microclimate instrument is in a stable state;

(2) According to the temperature and relative humidity of the lower surface of the fabric, as well as the temperature and relative humidity of the environment, calculate the moisture resistance of the tested fabric and the air layer above it;

(3) Subtract the moisture resistance of the air layer to obtain the moisture resistance of the tested fabric.

得到被测面料及其上方空气层的湿阻，其中：R_e是被测面料及上方空气层的总湿阻；A被测面料测试面积；P_uf是被测面料下表面温度下被测面料下表面的饱和水汽压；P_a是环境温度下环境的饱和水汽压；P_w是盛水容器中表面温度控制在t_w时饱和水汽压；RH_s是被测面料下表面的相对湿度；RH_a是环境的相对湿度；E是水的汽化热，30°C时E=0.675W·h/g；G是通过被测面料的水蒸发量，G=πd²Δh，d是垂直供水管内直径;⊿h是单位时间水位下降高度。In the step (2) adopted

Obtain the moisture resistance of the tested fabric and its upper air layer, wherein: R _e is the total moisture resistance of the tested fabric and the upper air layer; A is the test area of the tested fabric; _Puf is the tested fabric at the lower surface temperature of the tested fabric Saturated water vapor pressure of the lower surface; P _a is the saturated water vapor pressure of the environment at ambient temperature; P _w is the saturated water vapor pressure when the surface temperature in the water container is controlled at t _w ; RH _s is the relative humidity of the lower surface of the tested fabric; RH _a is the relative humidity of the environment; E is the heat of vaporization of water, E=0.675W h/g at 30°C; G is the water evaporation through the tested fabric, G=πd ² Δh, d is the inner diameter of the vertical water supply pipe ; ⊿h is the water level drop height per unit time.

来得到的空气层的湿阻，其中：R_e0是空气层的湿阻，Pa·m²/W；A₀是盛水容器中水面表面积，m²；P_w是水表面温度控制在t_w时饱和水汽压，Pa；G₀可通过加热一平底容器中的水使其表面温度与被测面料温度相同，计算单位时间单位面积的蒸发量获得，g/m²h。The moisture resistance of the air layer in the step (3) adopts

The moisture resistance of the air layer is obtained from the air layer, where: R _e0 is the moisture resistance of the air layer, Pa·m ² /W; A ₀ is the surface area of the water surface in the water container, m ² ; P _w is the temperature of the water surface controlled at t _w Saturated water vapor pressure at hour, Pa; G ₀ can be obtained by heating water in a flat-bottomed container to make its surface temperature the same as that of the fabric to be tested, and calculating the evaporation per unit area per unit time, g/m ² h.

Beneficial effect

Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the prior art: the present invention adopts a microclimate instrument for testing, and the fabric does not directly contact the sweating skin, but together with the annular wall A microclimate space is formed, a temperature sensor detects the surface temperature of sweating simulated skin, another temperature sensor and a relative humidity sensor are placed under the tested fabric to detect the temperature and relative humidity of the lower surface of the fabric. After the system reaches a steady state, the amount of water falling in the water supply pipe per unit time is equal to the sweating amount of the simulated skin and the moisture permeability through the tested fabric. Therefore, the biggest feature of this microclimate instrument is that it can directly measure The water evaporation rate of the tested fabric. In addition to the measured temperature and relative humidity of the lower surface of the fabric, as well as the temperature and relative humidity of the environment, the moisture resistance of the fabric and the air layer above it can be directly calculated according to the moisture resistance formula, and the moisture resistance of the air layer is subtracted, which is the fabric own moisture resistance. Because the fabric tested by this method does not directly contact the sweating skin, the liquid water precipitated from the skin cannot directly immerse into the fabric. Therefore, the moisture resistance measured by this method is the moisture resistance of pure moisture passing through the fabric.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a schematic diagram of an air layer moisture resistance measuring device in the present invention.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Embodiments of the present invention relate to a microclimate instrument for measuring the moisture resistance of fabrics, as shown in FIG. 1 , comprising a heating disc 3 and a vertical water supply pipe 13, and a sweating simulated skin 9 is arranged above the heating disc 3 , the vertical water supply pipe 13 passes water into the cavity between the heating disc 3 and the simulated skin 9; An electric heating wire 2 for heating is provided; a first temperature sensor 5 is provided on the surface of the sweating simulated skin 9, and a second temperature sensor 6 and a humidity sensor 7 are provided on the lower surface of the tested fabric 8; the first temperature The sensor 5 , the second temperature sensor 6 and the humidity sensor 7 are all connected to the measurement and control system, and the measurement and control system is used to control the heating of the heating wire 2 . The heating disk 3 is provided with a thermal insulation cover 12, and the tested fabric 8 is suspended above the sweating simulated skin 9 through the thermal insulation cover 12 and the supporting cross 11. An insulating cover 1 is provided under the heating disk 3, and a third temperature sensor 4 is provided on the insulating cover 1, and the third temperature sensor 4 is connected with the measurement and control system. Wherein, the sweating simulated skin 9 is arched, and adopts the technique of sealing and isolating the air layer 10 .

The using method of the present invention comprises the following steps: use electric heating wire to heat, make the microclimate instrument be in stable state; According to the temperature and relative humidity of the lower surface of the fabric, and the temperature and relative humidity of the environment, then calculate the temperature of the fabric under test and the air above it. The moisture resistance of the layer; the moisture resistance of the tested fabric is obtained by subtracting the moisture resistance of the air layer.

Using the microclimate instrument in the present invention, the fabric and the sweating skin do not directly contact, but form a microclimate space together with the annular wall, a temperature sensor detects the surface temperature of the sweating simulated skin, another temperature sensor and the relative humidity The sensor is placed under the tested fabric to detect the temperature and relative humidity of the lower surface of the fabric. After the system reaches a steady state, the amount of water falling in the water supply pipe per unit time is equal to the sweating amount of the simulated skin and the moisture permeability through the tested fabric. Therefore, the biggest feature of this microclimate instrument is that it can directly measure The water evaporation rate of the tested fabric. In addition to the measured temperature and relative humidity of the lower surface of the fabric, as well as the temperature and relative humidity of the environment, the moisture resistance of the fabric and the air layer above it can be directly calculated according to the moisture resistance formula, and the moisture resistance of the air layer is subtracted, which is the fabric own moisture resistance. Because the fabric tested by this method does not directly contact the sweating skin, the liquid water precipitated from the skin cannot directly immerse into the fabric. Therefore, the moisture resistance measured by this method is the moisture resistance of pure moisture passing through the fabric.

The microclimate instrument used in the present invention uses PTFE microporous membrane composite fabric as the simulated skin of sweating, and is fixed above the aluminum heating disc, and the vertical water supply pipe feeds water into the cavity between the disc and the simulated skin. Due to the pressure, the simulated skin swells into an arched shape. When working, the average temperature of the simulated skin is controlled at 35°C, and liquid water is precipitated through the microporous membrane of the simulated skin and evaporates to form "sweat". In the microclimate space between the simulated skin and the tested fabric, since the simulated skin is arched, if the skin temperature is completely consistent, the center temperature of the fabric sample will be higher than that of the surrounding area because the middle part is closer to the fabric sample. The present invention uses the technology of sealing and isolating the air layer in the simulated skin to reduce the temperature of the raised center of the simulated skin, so that the surface temperature difference of the fabric sample is about 1°C. At the same time, in the steady-state process of the micro-climate space, the distribution of moisture concentration is basically stable. By detecting the temperature and relative humidity of a certain point on the lower surface of the fabric, the moisture concentration value under the entire fabric sample can be obtained. Then the total moisture resistance of the air layer on the upper surface of the fabric can be calculated as:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; uf</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; RH</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; RH</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; G</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them: R _e is the total moisture resistance of the fabric and the upper air layer, P _a m ² /W; A fabric test area, m ² ; t _w is the temperature of the lower surface of the fabric, ℃; t _a is the ambient temperature, ℃; P _uf is the saturated water vapor pressure of the lower surface of the fabric at temperature t _w , Pa; P _a is the saturated water vapor pressure of the environment at temperature t _a , Pa; P _w is the saturated water vapor pressure when the surface temperature in the water container is controlled at t _w , Pa; RH _s is the relative humidity of the lower surface of the fabric, %; RH _a is the relative humidity of the environment, %; E is the heat of vaporization of water, and E is 0.675W h/g at 30°C; Water evaporation, Pa·m ² /W; G=πd ² Δh, d is the inner diameter of the vertical water supply pipe, m; ⊿h is the drop height of the water level per unit time, m.

As shown in Figure 2, the moisture resistance of the air layer can be calculated by heating the water in a flat-bottomed container to make its surface temperature the same as that of the fabric pattern, and calculating the evaporation per unit area per unit time.

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; R</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them: R _e0 is the moisture resistance of the air layer, Pa m ² /W; A _O is the surface area of the water surface in the water container, m ² ; P _w is the saturated water vapor pressure when the water surface temperature is controlled at t _w , Pa, G ₀ is the water evaporation of the water container when the surface water temperature is controlled at t _w , g/h, E is the vaporization heat of water, and E is 0.675W·h/g at 30°C.

Then the moisture resistance R _ef of the fabric sample is: R _ef =R _e −R _e0 .

Referring to the relevant humidity resistance test standards, under the constant temperature and humidity conditions of 20±0.5°C and relative humidity of 65%±3%, apply a wind speed of 1±0.3m/s above the fabric sample of the microclimate meter to simulate The average temperature of the skin is controlled at 35°C. After the system is balanced, the measured water level drop height is 53mm, the temperature of the lower surface of the fabric is 30°C, and the relative humidity has reached 100%. It is known that the inner diameter of the water supply pipe is 6mm. According to the above formula ( 1), the total moisture resistance of the fabric and the air layer above is 54Pa·m ² /W. According to the water container under the same test conditions as the microclimate meter, the measured water evaporation is 680g/m2h, then the moisture resistance of the air layer is 4Pa·m ² /W, and the moisture resistance of the fabric sample is 50Pa·m ² /W.

It is not difficult to find that the present invention uses a microclimate instrument for testing. The fabric and the sweating skin do not directly contact, but form a microclimate space together with the annular wall. One temperature sensor detects the surface temperature of the sweating simulated skin, and the other temperature sensor The sensor and the relative humidity sensor are placed under the tested fabric to detect the temperature and relative humidity of the lower surface of the fabric. After the system reaches a steady state, the amount of water falling in the water supply pipe per unit time is equal to the sweating amount of the simulated skin and the moisture permeability through the tested fabric. Therefore, the biggest feature of this microclimate instrument is that it can directly measure The water evaporation rate of the tested fabric. In addition to the measured temperature and relative humidity of the lower surface of the fabric, as well as the temperature and relative humidity of the environment, the moisture resistance of the fabric and the air layer above it can be directly calculated according to the moisture resistance formula, and the moisture resistance of the air layer is subtracted, which is the fabric own moisture resistance. Because the fabric tested by this method does not directly contact the sweating skin, the liquid water precipitated from the skin cannot directly immerse into the fabric. Therefore, the moisture resistance measured by this method is the moisture resistance of pure moisture passing through the fabric.

Claims (8)

1. A microclimate meter for measuring the moisture resistance of fabrics, comprising a heating disc (3) and a vertical water supply pipe (13), characterized in that a sweating simulated skin ( 9), the vertical water supply pipe (13) passes water into the water-filled area between the heating disc (3) and the simulated skin (9); the tested fabric (8) is suspended in the sweat simulation Above the skin (9) and below the heating disc (3), a heating wire (2) for heating is provided; the surface of the sweating simulated skin (9) is provided with a first temperature sensor (5), and the measured The lower surface of the fabric (8) is provided with a second temperature sensor (6) and a humidity sensor (7); the first temperature sensor (5), the second temperature sensor (6) and the humidity sensor (7) are all connected with the measurement and control The system is connected, and the measurement and control system is used to control the heating of the heating wire (2). 2. The microclimate meter for measuring the moisture resistance of fabrics according to claim 1, characterized in that, the heating disc (3) is provided with a thermal insulation cover (12), and the tested fabric (8) passes through The heat preservation cover (12) and the supporting cross (11) are suspended above the sweating simulated skin (9). 3. The microclimate meter for measuring the moisture resistance of fabrics according to claim 1, characterized in that the sweating simulated skin (9) is arched and adopts the technology of sealing and isolating the air layer (10). 4. The microclimate meter for measuring the moisture resistance of fabrics according to claim 1, characterized in that the sweating simulated skin (9) is a PTFE microporous membrane composite fabric. 5. a method for using the microclimate meter for measuring the moisture resistance of fabrics according to any one of claims 1-4, characterized in that, comprising the following steps: (1) Use electric heating wire to heat, so that the microclimate instrument is in a stable state; (2) According to the water evaporation through the fabric, the temperature and relative humidity of the lower surface of the fabric, and the temperature and relative humidity of the environment, the moisture resistance of the tested fabric and the air layer above it is calculated; (3) Subtract the moisture resistance of the air layer to obtain the moisture resistance of the tested fabric. 6. The method according to claim 5, characterized in that, in the step (1), when the microclimate instrument is in a steady state, the average temperature of the simulated skin is controlled at 35°C. 7. The use method according to claim 5, characterized in that, the step (2) uses

Obtain the moisture resistance of the tested fabric and its upper air layer, wherein: R _e is the total moisture resistance of the tested fabric and the upper air layer; A is the test area of the tested fabric; _Puf is the tested fabric at the lower surface temperature of the tested fabric Saturated water vapor pressure of the lower surface; P _a is the saturated water vapor pressure of the environment at ambient temperature; P _w is the saturated water vapor pressure when the surface temperature in the water container is controlled at t _w ; RH _s is the relative humidity of the lower surface of the tested fabric; RH _a is the relative humidity of the environment; E is the heat of vaporization of water, E=0.675W h/g at 30°C; G is the water evaporation through the tested fabric, G=πd ² Δh, d is the inner diameter of the vertical water supply pipe ; ⊿h is the water level drop height per unit time. 8. The use method according to claim 5, characterized in that, the step (3) uses

The moisture resistance of the air layer is obtained, wherein: R _e0 is the moisture resistance of the air layer; A ₀ is the surface area of the water surface in the water container; P _w is the saturated water vapor pressure when the water surface temperature is controlled at t _w ; G ₀ can be heated The surface temperature of water in a flat-bottomed container is the same as the temperature of the fabric to be tested, and the evaporation amount per unit area per unit time is calculated.

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