This standard is applicable to the determination of the air permeability of daily-use coarse pottery, fine pottery and fine pottery products at room temperature. It can also be used to determine the air permeability of refractory products, building ceramics, porous ceramics, etc. GB 4736-1984 Method for determination of air permeability of daily-use pottery GB4736-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for permeability gas of pottery ware of daily use
Standard test method for permeablity gas of pottery ware of daily useUDC 666.64 : 539
GB4736—84
This standard is applicable to the test of the permeability of daily-use pottery, fine pottery and fine ceramic products at room temperature. It can also be used to test refractory products, building ceramics, porous ceramics, etc.
The permeability of daily-use pottery refers to the ability of daily-use pottery products to pass gas under a certain pressure difference. The method is to apply three different pressure differences at both ends of the sample, measure the nitrogen flow through the sample with a rotor flowmeter, and then calculate the permeability according to Andarcy's law.
Note: The technical standard takes into account the dynamic viscosity of the gas, so the results obtained cannot be directly compared with the results obtained by the method that does not consider the dynamic viscosity of the gas.
2 Equipment and use
2.1 The permeability test device is shown in Figure 1, and the process is shown in Figure 2. Figure 1 Permeability test device
National Bureau of Standards 1984-11-02 Issued
1985-08-01 Implementation
GB 4736-B4
1-Gas cylinder, 2-Regulating pressure packaging: 3-Gas tube: 4-Switch valve: 3-Gas buffer: 6-Effective gas valve, 7-Purge gauge, 8, 9-U-tube pressure gauge 10-Sample holder, 11-Pressure gauge, 12-Regulating pressure! 13—Plane valve Figure 2 Flowchart
2.1.1 Inlet measurement range is as follows:
0.1~1.51/mins
1 ~ 5 l/min
2.1.2 Outlet full or filled with bad effect,
0.005-0.051/minl
0.01~n.151/minl
0.1~1.51/minl
1 51/min.
2.t.3 Sample holder (3) and ring (Figure 4) sample
Figure 3 Sample holder
GB 47364
Liquid film
2.2 The sampling machine uses G200 engineering gold example stone drill, the drill hole diameter is 50mm. 2.3 Surface grinding machine.
2. 4 Electric drying oven.
2.5 Vernier caliper, precision 0.02mm.
Sample preparation
1. = 50 - H
H-sample thickness
Figure 4 Gasket ring
3.1 Take the bottom of six products of the same variety, and vertically drill several cylindrical (or sheet) samples with a diameter of 50mm. For glazed products, use a surface grinder to grind the macro-axial layer and the middle layer. For sintered products without glaze, the surface must also be ground off until the two surfaces of the sample are parallel. Thickness deviation of the same group of test blocks: less than 0.5mm for thin products: less than 1mm for thick-walled products. The thickness of the test block depends on the product and is generally close to the product thickness. When making comparative tests on different products, the thickness of the test block should be consistent, but one surface of the product should still be retained (only the glaze layer and the middle should be removed. For large products that should not be destroyed, a large sample of the test block can be made, and its thickness is equal to the bottom of the product. The manufacturing process conditions should be consistent with the product. The plane of the large sample of the test block must be larger than 100 mm, and then the sample is taken with a drill and the glaze layer is polished. 3.2 Select four pieces of the ground test sample, rinse them with water, and then place them in a drying oven under electric heating at 105-110℃. 4 Test steps
4.1 Check the air tightness of the permeability test device and the test plate system. 4.1.1 Use a zero permeability Steel is made into a concave cylinder with an outer weight of 50mm and a height of 50mm for empty test. According to the steps in Sections 4.3 and 4.4, the inlet pressure is adjusted to 250m%. If the internal force of the inlet system does not drop within 2 to 3min, and there is no pressure and flow in the outlet system, the entire measurement system can be considered to be airtight. 4.2 While doing the empty test, use soapy water to pass through the air line to check the double cylinder to each part of the outlet system until there is no leakage.
4.2 Measure the diameter and height of the test block with an accuracy of 0.1mm. 4
4.3 Sampling
GB 4736--84
4.3.1 Place the test block in the sealed cavity in the middle of the sample holder. If the thickness of the test block is less than 50mm, a gasket can be added to adjust the height to close to 50mmbZxz.net
4.3.2 Inflate with an air pump so that the latex bushing in the sealed cavity tightly wraps the sample to seal the side surface of the sample. The pressure in the sealed cavity is controlled at about t.5kgf/cm*.
4.9.3 Screw on the mold base and mold cover, connect the inlet and outlet pipes, and start the measurement. 4.4 Adjust the intake system
4..1 Open the hydrogen cylinder cock and adjust the output pressure to about 3kgf/cm2. 4.2 Turn on the switch valve to inflate the buffer. 4.4.3 Open the plane reading door and For the micro-adjusting valve, select the appropriate inlet air flow meter from large to small (select the one that is close to the full scale).
4.5 Adjust the outlet system
For the flat valve and micro-adjusting valve, select the appropriate outlet air flow meter from large to small (select the one that can almost reach the full scale)
4.6 After the inlet and outlet systems are stable, record the pressure, flow and temperature of the inlet and outlet systems during measurement. Each test block is measured under at least two different pressure differences. The inlet and outlet pipes can also be connected to the same pressure gauge to directly measure the pressure difference. When the pressure difference is large, a mercury pressure gauge is used, and when the pressure difference is small, a water column pressure gauge is used. 5 Result calculation
Calculated according to Darcy's law, the formula is:
K= 2.16×10°m
formula, K
air permeability, μm2,
-dynamic viscosity of nitrogen at test temperature, Pa·s, thickness of test block, mm,
diameter of test block, mm,
gas flow rate, I/min;
pressure difference between inlet pressure P and outlet pressure P at both ends of the test block, mm water column (or mm mercury column). The relative deviation between the air permeability measured at different pressure differences and its average value of the test block is less than 6%, otherwise it shall be re-measured. The dynamic viscosity of nitrogen at different temperatures is shown in Table 1. Table 1
Dynamic sticky orbit
[7, 1 × 10 6
17.2 ×10 -6
17.2 × 10 -6
17.3×10-6
17.3×10-G
17.4×10-#
17.4×10-*
17.5 × 10 -h
17.5 ×10 -6
Dynamic viscosity
17.6×10-6
17.6 × 10-5
17.7 × 10 -*
17.7 ×10-6
17.7 × 10-6
17.8×10-6
17.8×10-4
17.9×10-6
17.9 × 10-6
Dynamic viscosity
18,0×10-5
18.0×10-6
18. 1 × 10-6
18.1×10-6
[8.2× 10-6
18.2×10-6
18.2×10-6
18.3×10-6
6Records and reports
The original records and test reports of daily random air permeability determination are shown in Tables 2 and 3. Table 2 Daily test record of permeability of separators
Measurement unit:
Submitted quantity
Test sample
Test item
Test diameter
Test pressure
K=2.16×10mm
Main content:
Additional information:
kgf/cm2
l/in
Table 3 Test report
Sample number
Report number
Report date
kgf/cm2
Tester
Tester
This standard was proposed by the Ministry of Light Industry of the People's Republic of China and approved by the Ceramics Research Institute of the Ministry of Light Industry. This standard was drafted by the Jiangsu Ceramics Research Institute and the main drafters of this standard were Zhang Baoyu and Xu Yuyang.
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