CN114910402A - Method and device for testing vapor permeability coefficient of porous material of building envelope - Google Patents

Abstract

The invention relates to a method and a device for testing the vapor permeability coefficient of porous materials of an enclosure structure, which consists of a sample fixing part, a lower part, an upper part, an air parameter recording and a temperature control system. Specimen-holding components include specimen-retaining rings and fasteners for holding appropriately sized specimens of porous material. The lower part and the upper part are used to accommodate two different saturated salt solutions, connect with the sample fixing part, and form two closed spaces above and below the sample respectively, so that the two sides of the porous material sample can be kept relatively constant. Relative Humidity Gradient. The air parameter recording and temperature control system is used to record the air parameters on both sides of the sample in real time during the test, and control the air temperature to the set value. By changing the set temperature, the type of saturated salt solution and the quality change of different parts, the invention can calculate the vapor permeability coefficient of the sample under different temperatures and water contents.

Description

A method and device for testing the vapor permeability coefficient of porous materials of enclosure structures

【Technical field】

The invention relates to a method and a device for testing the performance of building materials, in particular to a method and device for testing the vapor permeability coefficient of a porous material of an enclosure structure, and belongs to the technical field of construction engineering.

【Background technique】

In addition to heat, moisture will also be introduced into the room through the building envelope, and accumulated and released in the envelope, which changes the thermal and moisture physical parameters of the envelope and the indoor thermal and humidity environment, which in turn affects the energy consumption of heating and air conditioning, and the indoor heat and humidity. Human comfort, mildew and condensation on the exterior and interior of the envelope had an impact. The vapor permeability coefficient characterizes the speed of water vapor transfer in the material, and determining this parameter is crucial to measure the impact of moisture transfer in the building envelope.

However, the vapor permeability coefficient of a material will vary with the temperature and moisture content of the material. my country has a vast territory and various building climate zones. When the regions and seasons change, the vapor permeability coefficient of materials also changes greatly. Therefore, when measuring the effect of moisture transfer in the building envelope, the vapor permeability coefficient should not be regarded as a constant; when testing the vapor permeability coefficient, its specific value under different temperature and moisture content should also be tested.

At present, the dry/wet cup method is mainly used at home and abroad to measure the steam permeability coefficient. The sample and the open container are fixed with epoxy resin, paraffin and other materials, and then placed in a constant temperature and humidity box, so that the air on both sides of the sample has a constant and as small a relative humidity gradient as possible. The vapor permeability coefficient of the sample was obtained by calculating the weight loss rate, and it was expressed as a single-valued function of the relative humidity of the environment.

It can be seen from the above test process that the traditional test device still has the following deficiencies: 1) The traditional test device only controls the relative humidity on one side of the sample, and the relative humidity on the other side of the sample needs to be controlled by a constant temperature and humidity chamber, High cost and large footprint; 2) It is difficult to directly measure the height of the liquid level in the cup and the thickness of the air layer, and it is inconvenient to correct the influence of the vapor transmission resistance in the air; 3) The sample and the open container are fixed at one time, and the sample cannot be Reuse: 4) It is difficult to quickly adjust the relative humidity and temperature of the air on both sides of the sample, which is not conducive to testing the vapor permeability coefficient of the sample under various working conditions. In addition to the test device, the traditional test method is also worth improving: 1) the vapor permeability coefficient is expressed as a single-valued function of relative humidity, which does not conform to physical laws, and should be expressed as a function of temperature and moisture content; 2) due to various factors Influence, the relative humidity created by the saturated salt solution or the constant temperature and humidity box is not exactly the same as the theoretical value. Only by directly measuring the air parameters (temperature, relative humidity and air pressure) on both sides of the sample can the sample be accurately calculated. The vapor permeability coefficient under this condition.

Therefore, in order to solve the above-mentioned technical problems, it is indeed necessary to provide an innovative method and device for testing the vapor permeability coefficient of porous materials of enclosure structures, so as to overcome the defects in the prior art.

[Content of the invention]

The purpose of the present invention is to provide a method for measuring the vapor permeability coefficient of porous materials of an enclosure structure, which can calculate the temperature and moisture content of the sample at different temperatures by changing the set temperature, the type of saturated salt solution, and the quality changes of different parts. the vapor permeability coefficient.

Another object of the present invention is to provide a device for testing the vapor permeability coefficient of porous materials of an enclosure structure. Vapor permeability coefficients of structural porous materials at different temperatures and moisture contents.

In order to achieve the above-mentioned first purpose, the technical solution adopted in the present invention is: a method for testing the vapor permeability coefficient of porous materials of an enclosure structure, which comprises the following process steps:

1), use the sample fixing ring and the fastener to fix the dry sample of the porous material of the enclosure structure, cover the upper temporary sealing cover and the lower temporary sealing cover, and weigh the mass with an electronic balance, which is recorded as m ₀ ;

2), configure different kinds of saturated salt solutions or deionized water, inject them into the lower liquid holding part and the upper liquid holding part respectively, remove the upper temporary sealing cover and the lower temporary sealing cover, so that the lower liquid holding part and the upper liquid holding part are removed The upper liquid holding part is connected with the sample fixing part by threads;

3), put the lower air parameter measurement module and the upper air parameter measurement module into the lower air parameter measurement module fixing slot and the upper air parameter measurement module fixing slot, and connect the connected lower liquid holding part and upper liquid holding part with The sample fixing part is placed on the base, and the temperature control cover is covered to form a current path, and the experimental temperature T is set through the data acquisition and temperature control module to start the experiment;

4) In the first stage, the sample mass is weighed with an electronic balance every 1 day until the difference between the two weighing results does not exceed 0.1%, the mass at this time is recorded as m, the moisture content of the sample mass is calculated, and Denoted as ω, the formula for calculating mass moisture content is:

5), in the second stage, take the quality of the lower liquid holding part and the upper liquid holding part once every 1 day with an electronic balance, continuously weigh more than 5 days, and record the lower liquid holding part and the upper liquid holding part. The mass change rate, and according to the air parameters in the two confined spaces above and below the sample recorded by the data acquisition and temperature control module and the thickness of the air layer read out from the lower liquid holding part, the steam of the sample under the condition of the moisture content is calculated. permeability coefficient;

6), if it is necessary to measure the steam permeability coefficient at different temperatures or moisture contents, change the type of saturated salt solution, and repeat steps 2) to 5).

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further as follows: the step 5) is specifically:

5-1), assuming that the relative humidity in the closed space below the sample is greater than the relative humidity in the closed space above the sample, the mass growth rate of the lower liquid holding part and the upper liquid holding part is _Gu , when G _d and When the difference between G _u does not exceed 5%, it is considered that the test process is correct, and the test continues; when the difference between G _d and G _u exceeds 5%, the test is considered to have failed, and it is necessary to reconfirm whether the components are tightly connected, and repeat the procedure from step 1) Start the test; denote the surface area of the sample parallel to the horizontal plane as A, calculate the steam transfer rate per unit area, and denote it as g _v , the calculation formula of the steam transfer rate per unit area is:

空气压力p_u；下方空气参数为温度T_d、相对湿度

空气压力p_d；当T、T_u与T_d间相差均不超过5％时，认为测试过程无误，测试继续；当T、T_u与T_d间相差超过5％时，认为此次测试失败，应重新确认各部件是否连接紧密，并重新由步骤1)开始测试；计算试样上方与下方两个密闭空间内的水蒸气分压力，并分别记为p_v,u和p_v,d，试样上方与下方两个密闭空间内的水蒸气分压力的计算公式分别为：

和

计算试样两侧水蒸气分压力差，并记为Δp_v，水蒸气分压力差的计算公式为：Δp_v＝p_v,d-p_v,u；计算测试装置中蒸汽传递的总阻力，并记为R_total，测试装置中蒸汽传递的总阻力的计算公式为：

5-2), according to the air parameters in the two confined spaces above and below the sample recorded by the data acquisition and temperature control module, the air parameters above are temperature _Tu , relative humidity

Air pressure p _u ; the air parameters below are temperature T _d , relative humidity

Air pressure p _d ; when the difference between T, _Tu and T _d is not more than 5%, the test process is considered to be correct, and the test continues; when the difference between T, _Tu and T _d exceeds 5%, the test is considered to have failed , should reconfirm whether the components are tightly connected, and start the test again from step 1); calculate the partial pressure of water vapor in the two closed spaces above and below the sample, and record them as p _v,u and p _v,d respectively, The formulas for calculating the partial pressure of water vapor in the two closed spaces above and below the sample are:

and

Calculate the water vapor partial pressure difference on both sides of the sample, and denote it as Δp _v . The calculation formula of the water vapor partial pressure difference is: Δp _v =p _v,d -p _v,u ; Calculate the total resistance of steam transmission in the test device, And denoted as R _total , the calculation formula of the total resistance of steam transmission in the test device is:

读出上方空气层厚度，记为h_air,u，计算上方空气层的蒸汽传递阻力，并记为R_air,u，上方空气层的蒸汽传递阻力的计算公式为：

5-3), according to the thickness of the lower air layer read from the lower liquid holding part, denoted as h _air,d , and calculate the vapor transfer resistance of the lower air layer according to the standard atmospheric pressure p ₀ and the ideal gas constant R of water vapor, and Denoted as R _air,d , the formula for calculating the vapor transfer resistance of the lower air layer is:

Read out the thickness of the upper air layer, denoted as h _air,u , calculate the steam transfer resistance of the upper air layer, and denote it as R _air,u , the calculation formula of the steam transfer resistance of the upper air layer is:

即得到了该试样在温度为T、含水率为ω情况下的蒸汽渗透系数。5-4), record the thickness of the sample as h, calculate the vapor permeability coefficient of the sample, and record it as δ, the calculation formula of the sample vapor permeability coefficient is:

That is, the vapor permeability coefficient of the sample under the condition of temperature T and moisture content ω is obtained.

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further as follows: the sample fixing ring is composed of two symmetrical parts, which form a space with a square cross section and an upper and lower connection when they are closed; the sample fixing ring is directly connected to the sample. A soft silicone sealing ring is attached to the connecting surface; a slot is provided at the junction of the two symmetrical parts of the sample fixing ring, and the two parts of the sample fixing ring are tightly connected by a fastener; The lower surface is embedded with magnets; the outer periphery of the sample fixing ring is provided with threads; the center of the threads is provided with a wing-shaped accessory member; the wing-shaped accessory member is attached with a soft silicone sealing ring up and down, so that the lower liquid holding part and the upper liquid holding part pass through The thread is connected with the sample fixing part to form a closed space.

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further as follows: the fastener is composed of an upper half and a lower half; the cross section of the upper half is square; the lower half is H-shaped; the lower half is completely inserted In the empty groove of the sample fixing ring, the two parts of the sample fixing ring are tightly connected.

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further as follows: a magnet is embedded on the top of the wall surface of the lower liquid holding part; There is a lower air parameter measurement module fixing groove inside the wall of the holding part, which is used to fix the lower air parameter measurement module; the inner wall of the lower liquid holding part is provided with a thread on the upper part; the lower liquid holding part is connected to the sample through the screw thread. The fixed parts are connected and form a closed space.

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further as follows: a magnet is embedded in the bottom of the wall surface of the upper liquid holding part; a solution holding tank is connected inside the upper liquid holding part; the upper liquid holding part is There is an upper air parameter measurement module fixing groove inside the wall surface of the tester, which is used to fix the upper air parameter measurement module; the lower part of the wall surface of the upper solution holding part is provided with a thread; the upper solution holding part is connected with the sample fixing part through the thread , and form a closed space.

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further: the lower air parameter measurement module is composed of a temperature sensor with a measurement range of not less than 0 to 85°C and an accuracy of not less than ±0.5°C, and a measurement range of not less than 0 to The relative humidity sensor with 100% RH and accuracy not less than ±3% RH, the measurement range of not less than 90000~110000Pa and the air pressure sensor with accuracy not less than 10Pa is integrated. The air parameter measurement module is connected with the data acquisition and temperature control module through wires Directly connected, the wiring is covered with a silicone soft plug.

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further: the upper air parameter measurement module is composed of a temperature sensor with a measurement range of not less than 0 to 85°C and an accuracy of not less than ±0.5°C. The measurement range is not less than 0 to 85°C. The relative humidity sensor with 100% RH and accuracy not less than ±3% RH, the measurement range of not less than 90000~110000Pa and the air pressure sensor with accuracy not less than 10Pa is integrated. The air parameter measurement module is connected with the data acquisition and temperature control module through wires Directly connected, the wiring is covered with a silicone soft plug.

The method for testing the vapor permeability coefficient of the porous material of the enclosure structure of the present invention is further as follows: the temperature control cover is obtained by combining an electric heating layer, a thermal insulation material layer and a shell, and the temperature control cover is connected to the base through a conductive plug to form a current path; The base is connected with the temperature control cover through a conductive socket and forms a current path; the base is directly connected with the data acquisition and temperature control module through wires

In order to achieve the above-mentioned second purpose, the technical scheme adopted in the present invention is: a steam permeability coefficient testing device for porous materials of an enclosure structure, which includes a sample fixing part, a lower part, an upper part, an air parameter recording and a temperature control system:

The sample fixing part is used to fix the sample, and is composed of a sample fixing ring, a fastener, an upper temporary sealing cover and a lower temporary sealing cover; the bottom surface of the upper temporary sealing cover and the lower side The top surface of the temporary sealing cover is embedded with magnets;

The lower part is composed of a lower liquid holding part and a temporary sealing cover of the lower part; the bottom surface of the temporary sealing cover of the lower part is embedded with a magnet;

The upper part is composed of an upper liquid holding part, a top cover and a temporary sealing cover of the upper part; a thick soft silicone sealing ring is attached around the top cover; the top surface of the temporary sealing cover of the upper part is embedded with a magnet;

The air parameter recording and temperature control system is composed of a lower air parameter measurement module, an upper air parameter measurement module, a temperature control cover, a base and a data acquisition and temperature control module; the lower air parameter measurement module is installed in the lower liquid holding part The upper air parameter measurement module is installed in the upper liquid holding part; the lower part and the lower part are accommodated in the temperature control cover; the temperature control cover and the base are plugged; the data acquisition and temperature control module and the lower air The parameter measurement module and the upper air parameter measurement module are electrically connected.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention can calculate the vapor permeability coefficient of the sample at different temperatures and moisture contents by changing the set temperature, the type of saturated salt solution and the quality changes of different parts; at the same time, the present invention can be used without constant temperature and humidity. The test is completed with the aid of expensive large equipment such as a box, which reduces the test conditions.

2. The present invention can more conveniently adjust the relative humidity and temperature of the air on both sides of the sample, which is conducive to measuring the water vapor permeability coefficient of the sample under different temperatures and moisture contents, conforms to physical laws, and also helps to protect the enclosure. Accurate prediction of moisture transfer within structures;

3. The testing device of the present invention has the advantages of simple structure, small number of components, low failure rate, low cost per piece, and can be used in combination with multiple pieces. In addition, the test method is simple, the test data is easy to obtain and relatively accurate;

4. The same sample of the present invention can be used multiple times to avoid the influence of sample differences on the test results.

【Description of drawings】

FIG. 1 is a schematic structural diagram of the apparatus for testing the vapor permeability coefficient of the porous material of the enclosure structure according to the present invention.

FIG. 2 is a cross-sectional view of the sample fixing member in the present invention.

3-1 is an exploded perspective view of the sample fixing member and the sample in the present invention.

3-2 is a perspective view of the sample fixing member, the fastener and the sample in the present invention.

4 is a cross-sectional view of a lower member in the present invention.

Fig. 5 is a cross-sectional view of an upper member in the present invention.

6 is a cross-sectional view of the air parameter recording and temperature control system in the present invention.

Fig. 7 is a partial cross-sectional view of the present invention.

【Detailed ways】

Please refer to the accompanying drawings 1 to 7 of the description, the present invention is a test device for the vapor permeability coefficient of porous materials of an enclosure structure, which consists of a sample fixing part, a lower part, an upper part, an air parameter recording and a temperature control system.

The function of the sample fixing part is to fix the sample, which is composed of a sample fixing ring 1, a fastener 2, an upper temporary sealing cover 3 and a lower temporary sealing cover 4; the upper temporary sealing cover Magnets 3-1 and 4-1 are embedded in the bottom surface of 3 and the top surface of the lower temporary sealing cover 4.

Further, the sample fixing ring 1 in the sample fixing part is composed of two symmetrical parts; when the sample fixing ring 1 is closed, a space with a square cross-section and up and down is formed; the sample fixing ring 1 is directly connected to the sample. A soft silicone sealing ring 1-2 is attached to the connecting surface; a slot 1-3 is provided at the junction of the symmetrical two parts of the sample fixing ring 1, and the two parts of the sample fixing ring 1 can be tightened by the fastener 2 Connection; the upper and lower surfaces of the sample fixing ring 1 are embedded with magnets 1-4; the outer periphery of the sample fixing ring 1 is provided with threads 1-5; the center of the thread 1-5 is provided with a wing-shaped accessory member 1-6; -6 Soft silicone sealing rings 1-7 are attached up and down to form a closed space when the lower liquid holding part 5 and the upper liquid holding part 7 are connected with the sample fixing part by threads.

The fastener 2 is composed of an upper half part 2-1 and a lower half part 2-2; the upper half part 2-1 is square in section; the lower half part 2-2 is "H" shape; the lower half part 2-2 It can be completely inserted into the empty grooves 1-3 of the sample fixing ring 1, so that the two parts of the sample fixing ring 1 are tightly connected.

The function of the lower part is to hold saturated salt solution or deionized water, read the liquid height and fix the sensor, which is composed of the lower liquid holding part 5 and the temporary sealing cover 6 of the lower part; the temporary sealing cover 6 of the lower part is composed of The bottom surface of the magnet 6-1 is embedded.

A magnet 5-1 is embedded on the top of the wall surface of the lower liquid holding part 5 in the lower part; inside the wall surface of the lower liquid holding part 5, a scale line 5-2 is marked from the bottom; The inner wall of the part 5 is provided with a lower air parameter measurement module fixing groove 5-3 for fixing the lower air parameter measurement module 10; the inner wall of the lower liquid holding part 5 is provided with a thread 5-4 on the upper part; The placing part 5 can be connected with the sample fixing part through the thread 5-4 to form a closed space.

The function of the upper part is to hold saturated salt solution or deionized water and fix the sensor, which is composed of the upper liquid holding part 7, the top cover 8 and the temporary sealing cover 9 of the upper part; The top surface of the temporary sealing cover 9 of the upper part is embedded with a magnet 9-1.

A magnet 7-1 is embedded in the bottom of the wall of the upper liquid holding part 7 in the upper part; the interior of the upper liquid holding part 7 is connected with a solution holding groove 7-2; the interior of the wall of the upper liquid holding part 7 There is an upper air parameter measurement module fixing groove 7-3 for fixing the upper air parameter measurement module 11; the lower part of the wall surface of the upper solution holding part 7 is provided with a thread 7-4; the upper solution holding part 7 can pass through The thread 7-4 is connected with the sample fixing part to form a closed space.

The function of the air parameter recording and temperature control system is to record the temperature, relative humidity and pressure of the air in the lower part and the upper part in real time. The base 13 is composed of a data acquisition and temperature control module 14 . The lower air parameter measurement module 10 is installed in the lower liquid holding part 5 ; the upper air parameter measurement module 11 is installed in the upper liquid holding part 7 . The lower part and the lower part are accommodated in the temperature control cover 12 ; the temperature control cover 12 and the base 13 are plugged. The data acquisition and temperature control module 14 is electrically connected with the lower air parameter measurement module 10 and the upper air parameter measurement module 11, which can read various parameters measured.

The lower air parameter measurement module 10 in the air parameter recording and temperature control system consists of a temperature sensor 10-1 with a measurement range of not less than 0 to 85°C and an accuracy of not less than ±0.5°C, and a measurement range of not less than 0 to 100% RH. , The relative humidity sensor 10-2 with an accuracy of not less than ±3%RH, a measurement range of not less than 90000-110000Pa, and an air pressure sensor 10-3 with an accuracy of not less than 10Pa are integrated. The air parameter measurement module 10 collects data through wires It is directly connected with the temperature control module 14, and the wiring is covered with a silicone soft plug 10-4.

The upper air parameter measurement module 11 in the air parameter recording and temperature control system consists of a temperature sensor 11-1 with a measurement range of not less than 0 to 85°C and an accuracy of not less than ±0.5°C, and a measurement range of not less than 0 to 100% RH. , The relative humidity sensor 11-2 with an accuracy of not less than ±3%RH, the air pressure sensor 11-3 with a measurement range of not less than 90000-110000Pa and an accuracy of not less than 10Pa is integrated. The air parameter measurement module 11 collects data through wires It is directly connected with the temperature control module 14, and the wiring is covered with a silicone soft plug 11-4.

The temperature control cover 12 in the air parameter recording and temperature control system is obtained by combining the electric heating layer 12-1, the thermal insulation material layer 12-2 and the outer shell 12-3. The temperature control cover 12 is connected to the base 13 through the conductive plug 12-4. connected and form a current path.

The base 13 in the air parameter recording and temperature control system is connected to the temperature control cover 12 through a conductive socket 13-1 to form a current path; the base 13 is directly connected to the data acquisition and temperature control module 14 through wires.

Test method for vapor permeability coefficient of porous materials of building envelope by using the above device

1), the sample fixing ring 1 and the fastener 2 fix the dry sample of the porous material of the enclosure structure, cover the upper temporary sealing cover 3 and the lower temporary sealing cover 4, and weigh the mass with an electronic balance, denoted as m ₀ .

2), configure different kinds of saturated salt solution or deionized water, inject the lower liquid holding part 5 and the upper liquid holding part 7 respectively, remove the upper temporary sealing cover 3 and the lower temporary sealing cover 4, and make the lower liquid The holding part 5 and the upper liquid holding part 7 are connected to the sample fixing part by threads.

3), the lower air parameter measurement module 10 and the upper air parameter measurement module 11 are inserted into the lower air parameter measurement module fixing groove 5-3 and the upper air parameter measurement module fixing groove 7-3, and the connected lower liquid storage part 5 , The upper liquid holding part 7 and the sample fixing part are placed on the base 13, and the temperature control cover 12 is covered to form a current path, and the experiment temperature T is set through the data acquisition and temperature control module 14 to start the experiment.

4), in the first stage, the mass of the sample is weighed with an electronic balance every 1 day together with the sample fixing ring 1, the fastener 2, the upper temporary sealing cover 3 and the lower temporary sealing cover 4. Until the difference between the two weighing results does not exceed 0.1%, the mass at this time is recorded as m, the mass moisture content of the sample is calculated, and it is recorded as ω, and the calculation formula for mass moisture content is:

5), in the second stage, take the quality of the lower liquid holding part and the upper liquid holding part once every 1 day with an electronic balance, continuously weigh more than 5 days, and record the lower liquid holding part and the upper liquid holding part. The mass change rate, and according to the air parameters in the two confined spaces above and below the sample recorded by the data acquisition and temperature control module and the thickness of the air layer read out from the lower liquid holding part, the steam of the sample under the condition of the moisture content is calculated. permeability coefficient.

Specifically include the following process steps:

5-1), assuming that the relative humidity in the closed space below the sample is greater than the relative humidity in the closed space above the sample, the mass growth rate of the lower liquid holding part and the upper liquid holding part is _Gu , when G _d and When the difference between G _u does not exceed 5%, it is considered that the test process is correct, and the test continues; when the difference between G _d and G _u exceeds 5%, the test is considered to have failed, and it is necessary to reconfirm whether the components are tightly connected, and repeat the procedure from step 1) Start the test; denote the surface area of the sample parallel to the horizontal plane as A, calculate the steam transfer rate per unit area, and denote it as g _v , the calculation formula of the steam transfer rate per unit area is:

空气压力p_u；下方空气参数为温度T_d、相对湿度

空气压力p_d；当T、T_u与T_d间相差均不超过5％时，认为测试过程无误，测试继续；当T、T_u与T_d间相差超过5％时，认为此次测试失败，应重新确认各部件是否连接紧密，并重新由步骤1)开始测试；计算试样上方与下方两个密闭空间内的水蒸气分压力，并分别记为p_v,u和p_v,d，试样上方与下方两个密闭空间内的水蒸气分压力的计算公式分别为：

和

计算试样两侧水蒸气分压力差，并记为Δp_v，水蒸气分压力差的计算公式为：Δp_v＝p_v,d-p_v,u；计算测试装置中蒸汽传递的总阻力，并记为R_total，测试装置中蒸汽传递的总阻力的计算公式为：

5-2), according to the air parameters in the two confined spaces above and below the sample recorded by the data acquisition and temperature control module, the air parameters above are temperature _Tu , relative humidity

Air pressure p _u ; the air parameters below are temperature T _d , relative humidity

Air pressure p _d ; when the difference between T, _Tu and T _d is not more than 5%, the test process is considered to be correct, and the test continues; when the difference between T, _Tu and T _d exceeds 5%, the test is considered to have failed , should reconfirm whether the components are tightly connected, and start the test again from step 1); calculate the partial pressure of water vapor in the two closed spaces above and below the sample, and record them as p _v,u and p _v,d respectively, The formulas for calculating the partial pressure of water vapor in the two closed spaces above and below the sample are:

and

Calculate the water vapor partial pressure difference on both sides of the sample, and denote it as Δp _v . The calculation formula of the water vapor partial pressure difference is: Δp _v =p _v,d -p _v,u ; Calculate the total resistance of steam transmission in the test device, And denoted as R _total , the calculation formula of the total resistance of steam transmission in the test device is:

读出上方空气层厚度，记为h_air,u，计算上方空气层的蒸汽传递阻力，并记为R_air,u，上方空气层的蒸汽传递阻力的计算公式为：

5-3), according to the thickness of the lower air layer read from the lower liquid holding part, denoted as h _air,d , and calculate the vapor transfer resistance of the lower air layer according to the standard atmospheric pressure p ₀ and the ideal gas constant R of water vapor, and Denoted as R _air,d , the formula for calculating the vapor transfer resistance of the lower air layer is:

Read out the thickness of the upper air layer, denoted as h _air,u , calculate the steam transfer resistance of the upper air layer, and denote it as R _air,u , the calculation formula of the steam transfer resistance of the upper air layer is:

即得到了该试样在温度为T、含水率为ω情况下的蒸汽渗透系数。5-4), record the thickness of the sample as h, calculate the vapor permeability coefficient of the sample, and record it as δ, the calculation formula of the sample vapor permeability coefficient is:

That is, the vapor permeability coefficient of the sample under the condition of temperature T and moisture content ω is obtained.

6), if it is necessary to measure the steam permeability coefficient at different temperatures or moisture contents, change the type of saturated salt solution, and repeat steps 2) to 5).

To sum up, the present invention sets the characteristics of two air environments under different working conditions on both sides of the porous material of the enclosure under test, and can monitor and set the temperature, relative humidity and air pressure of the two air environments respectively, for The test of the vapor permeability coefficient of the porous material of the envelope structure under various working conditions of temperature and moisture content makes up for the defect that the existing device needs to be tested with the aid of large equipment such as constant temperature and humidity chambers, which is conducive to the development of multi-working conditions testing. , which also improves the accuracy of the test results. By adopting the device and method, the vapor permeability coefficient of the porous material of the envelope structure under different temperatures and moisture contents can be measured, so that the prediction result of the moisture transfer inside the envelope structure is more accurate and more in line with the actual situation, and it can be used for building load evaluation. , The optimization of thermal insulation and steam insulation of the envelope structure has provided great help.

The above specific embodiments are only preferred embodiments of this creation, and are not intended to limit this creation. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this creation shall be included in this creation. within the scope of protection.

Claims (10)

1. A method for testing vapor permeability coefficient of porous material of a building envelope is characterized by comprising the following steps: the method comprises the following process steps:

1) fixing a porous material oven-dried sample of the enclosure structure by using a sample fixing ring and a fastener, covering an upper temporary sealing cover and a lower temporary sealing cover, weighing the mass by using an electronic balance, and recording the mass as m ₀ ；

2) Preparing different kinds of saturated salt solutions or deionized water, respectively injecting the saturated salt solutions or the deionized water into the lower liquid containing part and the upper liquid containing part, and detaching the upper temporary sealing cover and the lower temporary sealing cover to enable the lower liquid containing part and the upper liquid containing part to be connected with the sample fixing part through threads;

3) placing a lower air parameter measuring module and an upper air parameter measuring module into a lower air parameter measuring module fixing groove and an upper air parameter measuring module fixing groove, placing a connected lower liquid containing part, an upper liquid containing part and a sample fixing part on a base, covering a temperature control cover to form a current path, setting an experiment temperature T through a data acquisition and temperature control module, and starting an experiment;

4) in the first stage, the mass of the sample is weighed once every 1 day by using an electronic balance until the difference between the two weighing results is not more than 0.1%, the mass is recorded as m, the mass water content of the sample is calculated and recorded as omega, and the calculation formula of the mass water content is as follows:

5) in the second stage, the mass of the lower liquid containing part and the mass of the upper liquid containing part are weighed once every 1 day by an electronic balance, the change rate of the mass of the lower liquid containing part and the mass of the upper liquid containing part is recorded for more than 5 days continuously, and the vapor permeability coefficient of the sample under the condition of the water content is calculated according to the air parameters in the two closed spaces above and below the sample recorded by the data acquisition and temperature control module and the thickness of the air layer read by the lower liquid containing part;

6) and if the vapor permeability coefficient under different temperatures or water contents needs to be measured, replacing the type of the saturated salt solution, and repeating the steps 2) to 5).

2. A method for testing vapor permeability coefficient of a porous material of a building envelope according to claim 1, characterized in that: the step 5) is specifically as follows:

5-1), assuming that the relative humidity in the closed space below the sample is higher than the relative humidity in the closed space above the sample, the mass growth rate of the lower liquid containing part and the upper liquid containing part is G _u When G is _d And G _u When the difference is not more than 5%, the testing process is considered to be correct, and the testing is continued; when G is _d And G _u When the difference is more than 5%, the test is considered to fail, whether the connection of each part is tight or not is confirmed again, and the test is started again from the step 1); the surface area of the sample parallel to the horizontal plane is designated A, the vapor transmission rate per unit area is calculated and designated g _v The vapor transfer rate per unit area is calculated by the formula:

5-2) according to the air parameters in the upper and lower closed spaces of the sample recorded by the data acquisition and temperature control module, wherein the upper air parameter is the temperature T _u Relative humidity of

Air pressure p _u (ii) a The lower air parameter is the temperature T _d Relative humidity of

Air pressure p _d (ii) a When T, T _u And T _d When the phase difference does not exceed 5%, the testing process is considered to be correct, and the testing is continued; when T, T _u And T _d When the difference is more than 5%, the test is considered to fail, whether the connection of each part is tight or not is confirmed again, and the test is started again from the step 1); calculating the partial pressure of water vapor in two closed spaces above and below the sample, and respectively recording as p _v,u And p _v,d The calculation formulas of the partial pressures of the water vapor in the two closed spaces above and below the sample are respectively as follows:

and

calculating partial pressure difference of water vapor on two sides of the sample and recording the partial pressure difference as delta p _v The calculation formula of the partial pressure difference of the water vapor is as follows: Δ p _v ＝p _v,d -p _v,u (ii) a The total resistance to vapor transmission in the test unit was calculated and recorded as R _total The calculation formula of the total resistance to steam transmission in the test unit is:

5-3), the thickness of the lower air layer, recorded as h, read from the lower liquid containing part _air,d And according to the standard atmospheric pressure p ₀ The vapor transmission resistance of the underlying air layer was calculated from the ideal gas constant R for water vapor and is noted as R _air,d The calculation formula of the steam transfer resistance of the lower air layer is as follows:

read the thickness of the upper air layer, and record as h _air,u The vapor transmission resistance of the upper air layer is calculated and is denoted as R _air,u The formula for calculating the steam transfer resistance of the upper air layer is as follows:

5-4), recording the thickness of the sample as h, calculating the vapor permeability coefficient of the sample as delta, and calculating the vapor permeability coefficient of the sample according to the formula:

that is, the vapor permeability coefficient of the sample was obtained at a temperature T and a water content ω.

3. A method for testing vapor permeability coefficient of a porous material of a building envelope according to claim 1, characterized in that: the sample fixing ring consists of two symmetrical parts, and a space which is square in section and is through up and down is formed when the sample fixing ring is folded; the surface of the sample fixing ring directly connected with the sample is attached with a soft silica gel sealing ring; slots are arranged at the joint of the two symmetrical parts of the sample fixing ring, and the two parts of the sample fixing ring are tightly connected through a fastener; magnets are embedded on the upper surface and the lower surface of the sample fixing ring; the periphery of the sample fixing ring is provided with threads; wing-shaped accessory components are arranged in the center of the thread; the upper part and the lower part of the wing-shaped accessory component are respectively provided with a soft silica gel sealing ring, so that the lower liquid containing part and the upper liquid containing part are connected with the sample fixing part through threads to form a closed space.

4. A method for testing vapor permeability coefficient of porous material of a building envelope according to claim 3, characterized in that: the fastener consists of an upper half part and a lower half part; the section of the upper half part is square; the lower half part is in an H shape; the lower half part is completely inserted into the empty groove of the sample fixing ring, so that the two parts of the sample fixing ring are tightly connected.

5. A method for testing vapor permeability coefficient of a porous material of a building envelope according to claim 1, characterized in that: a magnet is embedded at the top of the wall surface of the lower liquid containing part; the inner part of the wall surface of the lower liquid containing part is marked with scale marks from the bottom surface; a lower air parameter measuring module fixing groove is formed in the wall surface of the lower liquid containing part and used for fixing the lower air parameter measuring module; the upper part of the inner wall surface of the lower liquid containing part is provided with threads; the lower liquid containing part is connected with the sample fixing part through threads and forms a closed space.

6. The envelope porous material vapor permeability coefficient test method of claim 1, characterized in that: a magnet is embedded at the bottom of the wall surface of the upper liquid containing part; the inside of the upper liquid containing part is connected with a solution containing groove; an upper air parameter measuring module fixing groove is formed in the wall surface of the upper liquid containing part and used for fixing an upper air parameter measuring module; the lower part of the inner wall surface of the upper solution containing part is provided with threads; the upper solution containing part is connected with the sample fixing part through threads and forms a closed space.

7. A method for testing vapor permeability coefficient of a porous material of a building envelope according to claim 1, characterized in that: the lower air parameter measuring module is formed by integrating a temperature sensor with a measuring range of not less than 0-85 ℃ and a precision of not less than +/-0.5 ℃, a relative humidity sensor with a measuring range of not less than 0-100% RH and a precision of not less than +/-3% RH, and an air pressure sensor with a measuring range of not less than 90000-110000 Pa and a precision of not less than 10Pa, the air parameter measuring module is directly connected with the data acquisition and temperature control module through an electric wire, and a silica gel soft plug is sleeved on a wiring.

8. A method for testing vapor permeability coefficient of a porous material of a building envelope according to claim 1, characterized in that: the upper air parameter measuring module is formed by integrating a temperature sensor with a measuring range of not less than 0-85 ℃ and a precision of not less than +/-0.5 ℃, a relative humidity sensor with a measuring range of not less than 0-100% RH and a precision of not less than +/-3% RH, and an air pressure sensor with a measuring range of not less than 90000-110000 Pa and a precision of not less than 10Pa, the air parameter measuring module is directly connected with the data acquisition and temperature control module through an electric wire, and a silica gel soft plug is sleeved on a wiring.

9. A method for testing vapor permeability coefficient of a porous material of a building envelope according to claim 1, characterized in that: the temperature control cover is formed by combining an electric heating layer, a heat insulation material layer and a shell, and is connected with the base through a conductive plug to form a current path; the base is connected with the temperature control cover through the conductive socket and forms a current path; the base is directly connected with the data acquisition and temperature control module through an electric wire.

10. The utility model provides a building envelope porous material vapor permeability coefficient testing arrangement which characterized in that: the device comprises a sample fixing part, a lower part, an upper part and an air parameter recording and temperature control system:

the sample fixing part is used for fixing a sample and consists of a sample fixing ring, a fastener, an upper temporary sealing cover and a lower temporary sealing cover; magnets are embedded in the bottom surface of the upper temporary sealing cover and the top surface of the lower temporary sealing cover;

the lower part consists of a lower liquid containing part and a lower part temporary sealing cover; a magnet is embedded in the bottom surface of the lower part temporary sealing cover;

the upper part consists of an upper liquid containing part, a top cover and an upper part temporary sealing cover; thick soft silica gel sealing rings are attached to the periphery of the top cover; a magnet is embedded on the top surface of the temporary sealing cover of the upper part component;

the air parameter recording and temperature control system consists of a lower air parameter measuring module, an upper air parameter measuring module, a temperature control cover, a base and a data acquisition and temperature control module; the lower air parameter measuring module is arranged on the lower liquid containing part; the upper air parameter measuring module is arranged on the upper liquid containing part; the lower part and the lower part are accommodated in the temperature control cover; the temperature control cover is inserted into the base; the data acquisition and temperature control module is electrically connected with the lower air parameter measuring module and the upper air parameter measuring module.

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