Some standard content:
Chemical Industry Standard of the People's Republic of China
Test Method for Sealing Performance of Rubber Gaskets
1 Question Content and Applicable Pressure Range
HG/ T 2700-95
960754
This standard specifies two methods, A and B, for determining the sealing performance of rubber gaskets to liquids or gases at standard room temperature. This standard is applicable to standard room temperature, and uses leakage rate to evaluate the sealing performance of rubber gaskets under different compressive loads. Method A: Applicable to the determination of liquid leakage, and Method B! Used for the determination of gas leakage.
2 Reference standards
GB/T1690 Test methods for vulcanized rubber liquids GB2941 Standard temperature, humidity and temperature for environmental conditioning and testing of rubber specimens GB/T5723 Determination of dimensions of test specimens and products for vulcanized rubber or thermoplastic rubber testing GB9865 Preparation of vulcanized rubber samples and test specimens 3 Test principle
Apply a specified load to the annular specimen between two smooth steel flange surfaces, introduce the test medium into the center of the annular specimen, and apply a specified pressure to the medium after heating: For the gasket sealing performance test: it is recommended to use liquid A (see GB/T1690 Table 2), and the leakage rate is measured by the change of the liquid level of the liquid column indicator installed in the upstream of the gasket sealing performance test device pipeline. For the gas tightness test, it is recommended to use nitrogen, and the leakage rate is measured by the change of the liquid level of the liquid column indicator installed in the upstream of the gasket sealing performance test device pipeline.
4 Test Lai Zi
: The gasket sealing performance test device is mainly composed of a test flange, a pressure sensor, a liquid column indicator, a pressure regulating chest and pipelines, etc., and its connection is shown in Figure 1.
Approved by the Ministry of Chemical Industry of the People's Republic of China on May 5, 1995 and implemented on January 1, 1996
HG/T 2700 -
Figure 1 Gasket sealing performance tester test pipeline diagram Figure 1-Pressure regulator: 2-valve: 3-tee; 4-water area: 5-valve: 6-tee; %Liquid column indicator: 8-busy oil tank; 9-valve: 10-tee; 11-valve: 12-circuit valve; 13-tee; 14-liquid column indicator: 15-valve 16-tee: 17-valve: 18-pressure wheat: 19-loading nut; 20-pressure sensor: 21-plug; ·22-test chamber 41 Test flange
It consists of an upper and a lower steel flange, and the surface roughness Ra of its working surface is 0.80~1.60μm. 4.2 Pressure sensor
The diameter of the calibrated load sensor is faster than the required load range. 4.3 Liquid column indicator
A pressure-resistant glass tube with a length of about 280 mm, an inner diameter of about 1.6 mm, and a graduation value of 0.05 mL. 4.4 Pressure regulating valve
Used to adjust and control the gas source force.
4.5 Pipeline
Used to connect various components.
5 Sample
5.1 Sample preparation
The sample should be prepared according to the method specified in GB9865, either by molding or punching. The surface of the sample should be flat, without scratches and cracks.
5.2 Sample size
拼垮球票: Its inner diameter is 32.20~32.30mm, the outer diameter is 44.20~44.30mm, and the thickness is 0.70~0.80mm. 5. 3 Dimension measurement
HG/T 2700 —95
The thickness of the sample should be measured according to method A specified in GB/T5723, and the measurement value should be accurate to 0.01mm. 5.4 Number of samples
At least 3 samples for each material
5.5 Environmental conditioning of samples
Before the test, the prepared samples should be conditioned at standard room temperature according to GB2941. 6 Test steps
6. 1 Method A: Liquid leakage test
6.1.1 Cleaning of test flange
To remove the residues from the previous test, the working surfaces of the upper and lower flanges of the test flange should be cleaned. If necessary, use trifluoroethane to clean and check whether there are cracks or scratches. 6.1.2 Leakage inspection before test
Before the test, drain the water in the water storage tank 4, replace the annular sealing gasket sample with a rubber sheet with good elasticity (thickness of 2.5 mm or more), assemble it according to 6.1.3, and apply a load of 500 kgf, then open all the connecting valves in the system (only valve 12 and valve 15 are closed), and then fill the system with 0.21 MPa of effective gas, apply thin liquid to the system components and their pipeline connections, and visually check whether there is leakage. The test can be carried out only when there is no leakage. 6.1.3 Installation of the test sample
Place the test sample at the center of the lower flange of the test flange, put the upper flange on so that it is aligned with the lower flange, install the pressure sensor, and make the top plate of the test part produce the specified load (clamping force) on the test sample within 1 minute.6.1.4 Filling of the test liquid
First close valves 2 and 9. Open valves 15 and 11, close valve 17, and then open valve 12 to allow the test liquid in the oil tank 8 to flow into the test chamber and the liquid column indicator 14 through the pipeline, open the screw plug on the upper flange: when a small amount of test liquid flows out of the plugging hole, it means that the test chamber has been filled with test liquid. , continue filling until the liquid column in the liquid column indicator 14 reaches more than 1/2 of the liquid column indicator height, close valve 12, and then close valve 15.6.1.5 Determination of liquid leakage rate
Open the pressure regulating valve 1, so that the pressure gauge 18 indicates the specified pressure value (if not specifically stated, generally 0.21MPa), gently open the valve 17, and let the gas pass through the pipeline to the upper end of the liquid column indicator to squeeze the liquid column. After the liquid level of the liquid column indicator stabilizes, open valve 17 to the maximum to make the liquid in the test chamber reach the specified pressure. After stabilization for 5 minutes, read the liquid level height of the liquid column indicator 14 at 5 minutes. Take this reading as the starting reading, and read and record the liquid level height of the liquid column indicator at regular intervals. The time interval (such as 5, 10, 30 minutes or 1 hour) should be selected according to the surface movement speed of the liquid column indicator, calculate the average volume change of three consecutive intervals, and express the liquid leakage rate in terms of the number of declines per hour. Note: The liquid leakage process is generally quite slow, and the test process often takes 1 to several hours. ② If there is no leakage for more than 2 hours, the working pressure can be appropriately increased after consultation with the user, but the maximum working pressure shall not exceed 0.5MP. 6. 1.6 Pressure relief of pipeline system
After the test is completed, close the valve 1 and then close the valve 17, open the upper flange plug, use a beaker to collect the test liquid discharged from the liquid column indicator and its downstream pipeline, then remove the flange load, remove the upper flange and the sample. Then open valves 1 and 17, and use the pressure-carrying gas to blow out the residual test liquid in the pipe. Pour the collected test liquid back into the oil storage 8 or dispose of it properly. 6.2 Method B: Gas leakage test
6.2.1 Cleaning of test flange
Same as 6.1.1,
6.2.2 Leakage check before test
Same as 6.1.2.
ww.bzsoso：com6.2.3 Installation of test specimen
Same as 6. 1.3,
HG/T2700—95
6.2.4 Determination of gas leakage rate
Close chest doors 2, 9, 11 and 17, open valves 5 and 9, slowly open valve 2 and pressure regulating valve 1, so that the pressure gauge 18 indicates a relatively small pressure (such as below 0.05MPa). At this time, the pressure-carrying gas is passed to the closed water storage tank and the test chamber through the three-way joint. The water in the water storage tank will enter the liquid column indicator 7 along the pipeline and form a water column of a certain height (generally not exceeding 1/3 of the height of the liquid column indicator). Close the reading door 2 to prevent the water column from overflowing the water column indicator 7 and entering the pipe. Adjust the pressure regulating valve 1 so that the pressure gauge 18 indicates the specified pressure (generally 0.10MPa unless otherwise specified). Then open valves 17 and 11 to fill the test chamber with pressure-carrying gas. At this time, the gas pressure in the test chamber immediately reaches the specified pressure and is balanced with the gas pressure in the water tank. The water column in the liquid column indicator 7 drops. By adjusting the opening degree of valves 17 and 11, the water column surface is at a height convenient for observation (below 1/3 of the liquid column indicator). Immediately close valve 11, then close valve 17, and open valve 2 to the maximum. At this time, the water column surface no longer moves significantly. Wait for it to stabilize to 0.5min, let the pressure at both ends of the axilla column indicator 7 fully balance, then close valve 5, and stabilize for another 3min, record the height of the water column at 3min as the starting reading, and then observe the well to record the height of the water column at regular intervals (such as 10, 5, 1min and 30s, etc.), calculate the average value of the change in the height of the water column at three consecutive time intervals, and convert it into a gas leakage rate expressed in milliliters per hour. Note: The D gas leakage process is quite fast, and the test can be completed within 30mln, so the water column height must be read quickly and accurately. @The maximum working pressure shall not exceed 0.21MPa. 6.2.5 Pressure relief of pipeline system
After the test, first close valve 1, open valve 17, then open valve 15, slowly release the pressure in the water tank, then open valve 11 to release the pressure in the closed test chamber. Test report
The test report shall include the following contents:
Name or code of sample:
Test method used (A or B):www.bzxz.net
Test medium and pressure applied to the medium: The load (clamping force) of the flange used:
Test temperature and duration of the leakage test: Average leakage rate of the sample:
Tester and reviewer:
Test date,
Additional notes:
This standard is issued by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China, and this standard is under the jurisdiction of the Northwest Rubber Industrial Products Research Institute of the Ministry of Chemical Industry: This standard was drafted by the Northwest Rubber Industrial Products Research Institute of the Ministry of Chemical Industry, and the drafters of this standard were Li Zongqi, Shuai Zhengcai, and Sun Liqun.
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