CN114910402A - Method and device for testing vapor permeability coefficient of porous material of building envelope - Google Patents
Method and device for testing vapor permeability coefficient of porous material of building envelope Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 76
- 230000035699 permeability Effects 0.000 title claims abstract description 64
- 238000000034 method Methods 0.000 title claims abstract description 40
- 239000011148 porous material Substances 0.000 title claims abstract description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 49
- 239000012266 salt solution Substances 0.000 claims abstract description 17
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 17
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- 230000008859 change Effects 0.000 claims abstract description 7
- 239000007788 liquid Substances 0.000 claims description 86
- 238000007789 sealing Methods 0.000 claims description 47
- 230000005540 biological transmission Effects 0.000 claims description 19
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 15
- 239000000741 silica gel Substances 0.000 claims description 15
- 229910002027 silica gel Inorganic materials 0.000 claims description 15
- 238000004364 calculation method Methods 0.000 claims description 14
- 238000012546 transfer Methods 0.000 claims description 11
- 239000000243 solution Substances 0.000 claims description 9
- 239000008367 deionised water Substances 0.000 claims description 7
- 229910021641 deionized water Inorganic materials 0.000 claims description 7
- 238000002474 experimental method Methods 0.000 claims description 6
- 238000005303 weighing Methods 0.000 claims description 5
- 238000005485 electric heating Methods 0.000 claims description 3
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- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
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Abstract
The invention relates to a method and a device for testing vapor permeability coefficient of a porous material of a building envelope. The sample holding member includes a sample holding ring and a fastener for holding a sample of porous material of suitable dimensions. The lower part and the upper part are used for containing two different saturated salt solutions, are connected with the sample fixing part and respectively form two closed spaces above and below the sample, so that two sides of the porous material sample keep a relatively constant relative humidity gradient. The air parameter recording and temperature control system is used for recording air parameters at two sides of the sample in the test process in real time and controlling the air temperature to a set value. According to the invention, the vapor permeability coefficients of the sample at different temperatures and water contents can be calculated by changing the set temperature, the type of the saturated salt solution and the mass change conditions of different parts.
Description
[ technical field ] A method for producing a semiconductor device
The invention relates to a method and a device for testing the performance of a building material, in particular to a method and a device for testing the vapor permeability coefficient of a porous material of an envelope structure, and belongs to the technical field of building engineering.
[ background of the invention ]
Besides heat, moisture can also be transmitted into the room through the building enclosure structure and is accumulated and released in the enclosure structure, so that the heat and humidity physical parameters of the enclosure structure and the indoor heat and humidity environment are changed, and further, the heat and humidity energy consumption of a heating and air conditioning system, the indoor human comfort level, and the mildew and condensation on the surface and the inside of the enclosure structure are influenced. The vapor permeability coefficient represents the speed of water vapor transmission in the material, and the determination of the parameter is important for measuring the influence caused by moisture transmission in the building envelope.
However, the vapor permeability coefficient of a material may vary depending on the temperature and water content of the material. China has broad breadth, various building climate partitions, and when the region and the season change, the vapor permeability coefficient of the material also changes greatly. Therefore, the vapor permeability coefficient should not be considered as a constant when measuring the effect of moisture transfer inside the building envelope; when testing the vapor permeability coefficient, the specific values of the vapor permeability coefficient under different temperature and water content conditions should be tested.
At present, the steam permeability coefficient is mainly measured by a dry/wet cup method at home and abroad, and the approximate process is as follows: injecting a certain amount of saturated salt solution into an open container, flatly placing a sample to be tested at the opening of the container, fixing the sample and the open container by using materials such as adhesive tapes, epoxy resin, paraffin and the like, then placing the open container in a constant-temperature constant-humidity box, enabling air at two sides of the sample to have constant relative humidity gradient as small as possible, calculating the vapor permeability coefficient of the sample through the weight gain/weight loss rate of the saturated salt solution, and expressing the vapor permeability coefficient as a single-value function of the environmental relative humidity.
As can be seen from the above testing process, the conventional testing device has the following disadvantages: 1) the traditional testing device only controls the relative humidity of one side of a sample, and the relative humidity of the other side of the sample needs to be controlled by a constant temperature and humidity box, so that the cost is high, and the occupied area is large; 2) the liquid level height and the air layer thickness in the cup are difficult to directly measure, and the influence of the transmission resistance of the steam in the air is inconvenient to correct; 3) the sample and the open container are fixed at one time, and the sample can not be reused: 4) the relative humidity and the temperature of the air on the two sides of the sample are difficult to adjust rapidly, and the vapor permeability coefficient of the sample under various working conditions is not easy to test. In addition to the test device, the conventional test method is also worth improving: 1) expressing the vapor permeability coefficient as a single-value function of relative humidity, which does not accord with the physical law and is expressed as a function of temperature and water content; 2) because of the influence of various factors, the relative humidity created by the saturated salt solution or the constant temperature and humidity chamber is not completely the same as the theoretical value, and the vapor permeability coefficient of the sample under the working condition can be accurately calculated only by directly measuring the air parameters (temperature, relative humidity and air pressure) at the two sides of the sample.
Therefore, in order to solve the above technical problems, it is necessary to provide an innovative method and apparatus for testing vapor permeability coefficient of porous material of building envelope, so as to overcome the above drawbacks in the prior art.
[ summary of the invention ]
The invention aims to provide a method for testing the vapor permeability coefficient of a porous material of a building envelope, which can calculate the vapor permeability coefficient of a sample at different temperatures and water contents by changing the set temperature, the type of a saturated salt solution and the mass change conditions of different parts.
The invention also aims to provide a device for testing the vapor permeability coefficient of the porous material of the building envelope, which has the advantages of simple structure, small number of parts, low failure rate, simple and convenient use and easy acquisition of test data, and can accurately measure the vapor permeability coefficient of the porous material of the building envelope at different temperatures and water contents.
In order to achieve the first object, the invention adopts the technical scheme that: a method for testing vapor permeability coefficient of a porous material of a building envelope 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 steam permeability coefficient under different temperatures or water contents needs to be measured, replacing the saturated salt solution type, and repeating the steps 2) to 5).
The method for testing the vapor permeability coefficient of the porous material of the envelope further comprises the following steps: the step 5) is specifically as follows:
5-1), the lower part liquid containing part and the upper part liquid containing part are assumed that the relative humidity in the closed space below the sample is larger than that in the closed space above the sample at the momentPart of the mass growth rate 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 the sample
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 Partial pressure difference meter for water vapourThe calculation formula 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 denoted as R air,d The formula for calculating the vapor transfer resistance of the lower air layer is:
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 by the following formula:
that is, the vapor permeability coefficient of the sample was obtained at a temperature T and a water content ω.
The method for testing the vapor permeability coefficient of the envelope porous material further comprises the following steps: 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; a soft silica gel sealing ring is attached to the surface of the sample fixing ring which is directly connected with the sample; 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 in 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 part liquid containing part and the upper part liquid containing part are connected with the sample fixing part through threads to form a closed space.
The method for testing the vapor permeability coefficient of the porous material of the envelope further comprises the following steps: 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.
The method for testing the vapor permeability coefficient of the porous material of the envelope further comprises the following steps: 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.
The method for testing the vapor permeability coefficient of the porous material of the envelope further comprises the following steps: 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.
The method for testing the vapor permeability coefficient of the porous material of the envelope further comprises the following steps: 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.
The method for testing the vapor permeability coefficient of the porous material of the envelope further comprises the following steps: 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, 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.
The method for testing the vapor permeability coefficient of the porous material of the envelope further comprises the following steps: 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
In order to achieve the second object, the invention adopts the technical scheme that: a vapor permeability coefficient testing device for a porous material of a building envelope comprises a sample fixing part, a lower part, an upper part and an air parameter recording and temperature control system, wherein the sample fixing part comprises a sample fixing part body and a sample fixing part body, and the air parameter recording and temperature control system comprises a sample fixing part body and a sample fixing part body, wherein the sample fixing part body comprises:
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.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the vapor permeability coefficients of the sample at different temperatures and water contents can be calculated by changing the set temperature, the type of saturated salt solution and the mass change conditions of different parts; meanwhile, the invention can finish the test without the assistance of expensive large-scale equipment such as a constant temperature and humidity box and the like, thereby reducing the test condition.
2. The invention can conveniently adjust the relative humidity and temperature of the air at two sides of the sample, is beneficial to measuring the water vapor permeability coefficient of the sample under the conditions of different temperatures and water contents, conforms to the physical law and is also beneficial to accurately predicting the moisture transfer in the enclosure structure;
3. the testing device has the advantages of simple structure, less parts, low failure rate, low single piece manufacturing cost and capability of combining a plurality of parts for use. In addition, the test method is simple and convenient, and test data are easy to obtain and more accurate;
4. the same sample can be used for multiple times, and the influence on the test result due to the difference of the samples is avoided.
[ description of the drawings ]
FIG. 1 is a schematic structural diagram of a vapor permeability coefficient testing device for a building envelope porous material of the invention.
FIG. 2 is a sectional view of a sample holding member in the present invention.
Fig. 3-1 is an exploded perspective view of the sample fixing member and the sample according to the present invention.
Fig. 3-2 is a perspective view of a sample holding member, a fastener, and a sample in accordance with the present invention.
Fig. 4 is a cross-sectional view of a lower member in the present invention.
Fig. 5 is a cross-sectional view of the upper member of the present invention.
FIG. 6 is a cross-sectional view of an air parameter recording and temperature control system of the present invention.
Fig. 7 is a partial cross-sectional view of the present invention.
[ detailed description ] embodiments
Referring to the attached drawings 1-7 in the specification, the invention relates to a steam permeability coefficient testing device for porous materials of building enclosures, which 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 1, a fastener 2, an upper temporary sealing cover 3 and a lower temporary sealing cover 4; magnets 3-1 and 4-1 are embedded in the bottom surface of the upper temporary sealing cover 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 folded, a space with a square section and a through up-down structure is formed; the surface of the sample fixing ring 1 directly connected with the sample is attached with a soft silica gel sealing ring 1-2; slots 1-3 are arranged at the joint of the two symmetrical parts of the sample fixing ring 1, and the two parts of the sample fixing ring 1 can be tightly connected through a fastener 2; magnets 1-4 are embedded on the upper surface and the lower surface of the sample fixing ring 1; the periphery of the sample fixing ring 1 is provided with threads 1-5; wing-shaped accessory components 1-6 are arranged in the centers of the threads 1-5; the upper part and the lower part of the wing-shaped accessory component 1-6 are respectively provided with a soft silica gel sealing ring 1-7, so that when the lower liquid containing part 5 and the upper liquid containing part 7 are connected with the sample fixing part through threads, a closed space is formed.
The fastener 2 consists of an upper half part 2-1 and a lower half part 2-2; the section of the upper half part 2-1 is square; the lower half part 2-2 is H-shaped; the lower half part 2-2 can be completely inserted into the empty groove 1-3 of the sample fixing ring 1, so that the two parts of the sample fixing ring 1 are tightly connected.
The lower part has the functions of containing saturated salt solution or deionized water, reading the liquid height and fixing the sensor, and consists of a lower liquid containing part 5 and a lower part temporary sealing cover 6; the bottom surface of the lower part temporary sealing cover 6 is embedded with a magnet 6-1.
A magnet 5-1 is embedded at the top of the wall surface of the lower liquid containing part 5 in the lower part; the inside of the wall surface of the lower liquid containing part 5 is marked with scale lines 5-2 from the bottom surface; a lower air parameter measuring module fixing groove 5-3 is formed in the wall surface of the lower liquid containing part 5 and used for fixing a lower air parameter measuring module 10; the upper part of the inner wall surface of the lower liquid containing part 5 is provided with threads 5-4; the lower liquid-containing portion 5 may be connected to the sample-fixing member by means of a screw 5-4 to form a closed space.
The upper part has the functions of containing saturated salt solution or deionized water and fixing the sensor, and consists of an upper liquid containing part 7, a top cover 8 and an upper part temporary sealing cover 9; thick soft silica gel sealing rings 8-1 are attached to the periphery of the top cover 8; the top surface of the upper part temporary sealing cover 9 is embedded with a magnet 9-1.
A magnet 7-1 is embedded at the bottom of the wall surface of the upper liquid containing part 7 in the upper part; the inside of the upper liquid containing part 7 is connected with a solution containing groove 7-2; an upper air parameter measuring module fixing groove 7-3 is formed in the wall surface of the upper liquid containing part 7 and used for fixing an upper air parameter measuring module 11; the lower part of the inner wall surface of the upper solution containing part 7 is provided with a thread 7-4; the upper solution-containing portion 7 may be connected to the sample-fixing member by means of a screw 7-4 to form a closed space.
The air parameter recording and temperature control system has the function of recording the temperature, the relative humidity and the pressure of air in the lower part and the upper part in real time, and consists of a lower air parameter measuring module 10, an upper air parameter measuring module 11, a temperature control cover 12, a base 13 and a data acquisition and temperature control module 14. The lower air parameter measuring module 10 is installed in the lower liquid containing part 5; the upper air parameter measuring module 11 is installed at the upper liquid containing portion 7. The lower member and the lower member are housed in the temperature control cover 12; the temperature control cover 12 is inserted into the base 13. 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, and can read various measured parameters.
The lower air parameter measuring module 10 in the air parameter recording and temperature control system is obtained by integrating a temperature sensor 10-1 with a measuring range of not less than 0-85 ℃ and a precision of not less than +/-0.5 ℃, a relative humidity sensor 10-2 with a measuring range of not less than 0-100% RH and a precision of not less than +/-3% RH, an air pressure sensor 10-3 with a measuring range of not less than 90000-110000 Pa and a precision of not less than 10Pa, the air parameter measuring module 10 is directly connected with a data acquisition and temperature control module 14 through an electric wire, and a silica gel soft plug 10-4 is sleeved on a connecting wire.
An upper air parameter measuring module 11 in the air parameter recording and temperature control system is obtained by integrating a temperature sensor 11-1 with a measuring range of not less than 0-85 ℃ and a precision of not less than +/-0.5 ℃, a relative humidity sensor 11-2 with a measuring range of not less than 0-100% RH and a precision of not less than +/-3% RH, an air pressure sensor 11-3 with a measuring range of not less than 90000-110000 Pa and a precision of not less than 10Pa, the air parameter measuring module 11 is directly connected with a data acquisition and temperature control module 14 through an electric wire, and a connecting wire is sleeved with a silica gel soft plug 11-4.
The temperature control cover 12 in the air parameter recording and temperature control system is formed by combining an electric heating layer 12-1, a heat insulation material layer 12-2 and a shell 12-3, and the temperature control cover 12 is connected with a base 13 through a conductive plug 12-4 to form a current path.
A base 13 in the air parameter recording and temperature control system is connected with a temperature control cover 12 through a conductive socket 13-1 and forms a current path; the base 13 is directly connected with the data acquisition and temperature control module 14 through an electric wire.
Method for testing vapor permeability coefficient of porous material of building envelope by adopting device
1) The sample fixing ring 1 and the fastener 2 are used for fixing the envelope porous material oven-dried sample, the upper temporary sealing cover 3 and the lower temporary sealing cover 4 are covered, the mass is weighed by an electronic balance and is recorded as m 0 。
2) And different types of saturated salt solutions or deionized water are configured, the lower liquid containing part 5 and the upper liquid containing part 7 are respectively injected, the upper temporary sealing cover 3 and the lower temporary sealing cover 4 are detached, and the lower liquid containing part 5 and the upper liquid containing part 7 are connected with the sample fixing part through threads.
3) The lower air parameter measuring module 10 and the upper air parameter measuring module 11 are placed into a lower air parameter measuring module fixing groove 5-3 and an upper air parameter measuring module fixing groove 7-3, the connected lower liquid containing part 5, upper liquid containing part 7 and sample fixing part are placed on a base 13, a temperature control cover 12 is covered to form a current path, and an experiment temperature T is set through a data acquisition and temperature control module 14 to start an experiment.
4) In the first stage, the mass of the sample is weighed once every 1 day by using an electronic balance, and the mass together with the sample fixing ring 1, the fastener 2, the upper temporary sealing cover 3 and the lower temporary sealing cover 4 is weighed until the difference between the two weighing results is not more than 0.1%, the mass is recorded as m at the moment, 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) and 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 using 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 out by the lower liquid containing part.
The method specifically comprises the following process steps:
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 denoted as R air,d The calculation formula of the steam transfer resistance of the lower air layer is as follows:
read out the thickness of the upper air layer, which is recorded 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.
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).
In summary, the invention sets up the characteristics of two different working condition air environments on two sides of the porous material of the enclosure structure to be tested, and can respectively monitor and set up the temperature, the relative humidity and the air pressure of the two air environments, so as to be used for testing the vapor permeability coefficient of the porous material of the enclosure structure under various working condition temperatures and water contents, thereby overcoming the defect that the existing device needs to be tested under the assistance of large equipment such as a constant temperature and humidity box, being beneficial to the development of multi-working condition tests and also improving the accuracy of test results. By adopting the device and the method, the vapor permeability coefficient of the porous material of the enclosure structure under different temperatures and water contents can be measured, so that the prediction result of the moisture transmission in the enclosure structure is more accurate and more accords with the actual condition, and great help is provided for the optimization of building load evaluation, heat preservation, heat insulation and steam insulation of the enclosure structure and the like.
The above embodiments are merely preferred embodiments of the present disclosure, which are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like, which are within the spirit and principle of the present disclosure, should be included in the scope of the present disclosure.
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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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115711913A (en) * | 2022-11-28 | 2023-02-24 | 浙江大学 | Method for measuring thermal resistance and wet resistance of multi-size building envelope structure member based on building wind tunnel |
| CN116930042A (en) * | 2023-09-19 | 2023-10-24 | 常州建昊建筑鉴定检测有限公司 | Building waterproof material performance detection equipment and method |
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2022
- 2022-04-26 CN CN202210444799.8A patent/CN114910402A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115711913A (en) * | 2022-11-28 | 2023-02-24 | 浙江大学 | Method for measuring thermal resistance and wet resistance of multi-size building envelope structure member based on building wind tunnel |
| CN116930042A (en) * | 2023-09-19 | 2023-10-24 | 常州建昊建筑鉴定检测有限公司 | Building waterproof material performance detection equipment and method |
| CN116930042B (en) * | 2023-09-19 | 2023-12-01 | 常州建昊建筑鉴定检测有限公司 | Building waterproof material performance detection equipment and method |
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