GB/T 2679.13-1996 Determination of air permeability of paper and paperboard (medium range) Bendtsen method
Some standard content:
GB/T 2679.13--1996
This standard is equivalent to the international standard ISO5636-3:1992 "Determination of air permeability of paper and paperboard (medium range) - Part 3: Bendtsen method", which is equivalent to the international standard in technical content, but with some textual modifications. The Bendtsen instrument specified in this standard can also be used for the determination of roughness, but the results of the determination are different. The former uses surface leakage, while the latter uses the air flow through the paper surface. Appendix A and Appendix B of this standard are both standard appendices. This standard was proposed by the China Light Industry General Association.
This standard is under the jurisdiction of the National Technical Committee for Standardization of Paper Industry. This standard was drafted by the Guangdong Paper Research Institute and the China Pulp and Paper Industry Research Institute. The main drafters of this standard are: Sun Shaofang and Chen Xi. 330
GB/T 2679.13—1996
ISOForeword
ISO (International Organization for Standardization) is a worldwide federation of national standards research institutes (ISO member states). The development of international standards is usually carried out through ISO technical committees. Member states interested in projects for which technical committees have been established have the right to participate in the technical committees. International organizations of both governmental and non-governmental nature related to ISO may also participate in this work. ISO works closely with the International Electrotechnical Organization (IEC) on all electrotechnical standards. After the draft international standard is approved by the technical committee, it is sent to member states for voting. At least 75% of member states must vote in favor before it can be published as an international standard.
International standard ISO5636-3 was drafted by ISO/TC6, Technical Committee for Pulp, Paper and Paperboard, Subcommittee SC2, Test Methods and Quality Indicators for Paper and Paperboard.
ISO5636 consists of the following parts, with the general title: Paper and board--Determination of air permeance (medium range) and the following sub-titles:
Part 1: General method,
-Part 2: Schober method;
Part 3: Bendtsen method;
-Part 4: Sheffield method,
Part 5: Gurley method.
Appendix A and Appendix B are components of ISO5636. 331
1 Scope
National Standard of the People's Republic of China
Paper and board--Determination of air permeance (medium range) Bendtsen method
Paper and board--Determination of air permeance (medium range) Bendtsen method This standard specifies the method for determining the air permeability of paper and board using the Bendtsen instrument. Note: The Bendtsen instrument can also be used for the determination of Bendtsen roughness. GB/T2679.13-1996
eqv 1s 5636-3: 1992
This standard applies to paper and paperboard with air permeability between 0.35μm/(Pa·s) and 15uμm/(Pa·s). This standard does not apply to paper and paperboard with rough surface, such as crepe paper and corrugated base paper, because such paper is difficult to clamp and causes air leakage. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T450--89 Paper and paperboard sample collection GB/T10739--89 Pulp, paper and paperboard sample processing and testing standard 3 Terminology
3.1 Air permeability: The average air flow rate passing through a unit area of a sample in a unit time under a unit pressure difference, expressed in micrometers per Pascal seconds [1 mL/(m2.Pa· s)=l μm/(Pa· s)]. 4 Principle
The sample is clamped between a sealing gasket and a circular plane of known diameter, so that the absolute air pressure on one side of the sample is equal to the atmospheric pressure. The pressure difference on both sides is very small during the test, but it is quite stable. Within the specified time, the air flow rate passing through the test area is measured. 5 Instrument
The Bentsen instrument consists of a compressor, a pressure buffer container, a rotor flowmeter with a pressure regulating valve and a measuring head, see Figure 1. The maintenance details of the Bentsen instrument are shown in Appendix A (Standard Appendix). 5.1 Compressor
The compressor is used to generate airflow with a pressure of about 127kPa. If necessary, a filter can be installed to ensure that the air is clean and oil-free. 5.2 Pressure buffer container
The volume is about 10L and is installed between the compressor and the flow meter. 5.3 Pressure regulator
The flow meter inlet uses a pressure regulator to control the air pressure. Generally, this instrument has three pressure regulators, and the pressure control is 0.74kPa±0.01kPa, 1.47kPa±0.02kPa and 2.20kPa±0.03kPa. This standard stipulates that the pressure is 1.47kPa, that is, 150g should be used. 332 approved by the State Administration of Technical Supervision on May 21, 1996
Implementation on December 1, 1996
Pressure regulator heavy bowl.
5.4 Flowmeter
GB/T2679.13—1996
Generally, there are three different ranges of rotor flowmeters, namely 10mL/min～150mL/min, 50mL/min～500mL/min and some instruments are 300mL/min～3 000mL/min, and the readings are required to be accurate to 2 ml/min, 5 mL/min and 20 mL/min respectively.
Three capillaries with different flow rates should be prepared to calibrate the flowmeter, one for each flowmeter. The capillary itself should be accurately calibrated under the same pressure difference as the measuring head (such as calibration with a soap bubble meter). The calibration details of the flowmeter and capillary can be found in Appendix B (Standard Appendix). Note: Other calibration methods for flowmeters that meet the requirements of this standard may also be used, but this should be noted in the report. B
A—compressor; B-pressure buffer container; C—pressure stabilizing valve, D—central unit; E—sample clamping device Figure 1 Bentsen Instrument
5.5 Measuring head
The measuring head is used to clamp the sample between the annular plate and the annular sealing gasket. The dimensions of the annular ring and the sealing gasket should ensure that the test area of the clamped sample is 10cm±0.2cm2. If the sealing gasket is worn or deformed, it should be replaced in time. The measuring head and the flowmeter are connected with a rubber tube or plastic tube with an inner diameter of 5mm~6mm and a length of no more than 600mm. 6 Sample collection, preparation and processing
6.1 The sample is collected in accordance with GB/T450.
6.2 Cut no less than 10 test pieces of 50mm×50mm and mark the front and back sides. The test range of the sample cannot be touched by hand. The test surface should be free of folds, wrinkles, holes, watermarks or other unnecessary defects. 6.3 The sample is treated and tested according to the standard atmosphere of GB/T10739. 7 Test steps
7.1 Place the instrument on a stable workbench and adjust it to a horizontal level. Start the compressor and ensure that there is no vibration that affects the reading. 7.2 Select a flow meter with an appropriate range, try to use a 1.47kPa pressure regulator, and make the reading range within 80% of the flow meter scale. It is best not to use a flow rate less than 30mL/min and greater than 1200mL/min, because at high airflow, the pressure loss between the flow meter and the measuring head is enough to offset the calibration of the flow meter.
Turn the ventilation valve to allow airflow to flow into the selected flow meter, and then gently place the 1.47kPa pressure regulator on the shaft and rotate it. Note: The pressure regulator can only be placed on the shaft after the airflow flows in, and it should be taken out before stopping. 7.3 Adjust the outlet valve of the flow meter to increase the airflow, and connect it to the measuring head with a 600mm pipe (if the pipe is too long, it will cause pressure fluctuations between the flow meter and the measuring head). 7.4 Check for air leakage: Use a 10mL/min~150mL/min flowmeter, and clamp a smooth and hard non-metallic plate against the sealing gasket at the measuring head to check for air leakage. If the reading is not zero, check whether the non-metallic plate is damaged or defective. Make sure that the sealing gasket is in tight contact with the non-metallic thick plate, and check whether the air flow pipeline is tight to prevent leakage. Note: The flowmeter outlet has two outlet pipes. The measuring head should be connected to the outlet pipe for measuring air permeability according to the instrument instructions. 333
GB/T 2679.13—1996
7.5 Calibrate the flowmeter: Use an appropriate capillary to replace the measuring head. The air flow reading should be consistent with the calibration reading, accurate to ±5%. 7.6 Clamp the test piece between the annular plate and the sealing gasket, and record the flowmeter reading after clamping for 5s. The reading accuracy should meet the requirements of 5.4. Note: If high pressure is used, the sealing gasket will be damaged. 7.7 During the test, the front side of half of the test piece should face the gasket, and the back side of half of the test piece should face the gasket. 7.8 After the test, take out the pressure regulating valve first and then turn off the compressor. 8 Result representation
8.1 Calculation of air permeability (P)
Use 1.47kPa standard pressure difference and calculate the air permeability (P) of each test piece according to formula (1), μm/Pa·s; P = 0. 011 3 q
Where: 9-
The amount of air passing through the test surface of the sample per minute, mL/min. 8.2 Arithmetic mean
Calculate the arithmetic mean of the air permeability, expressed in um/(Pa·s), accurate to two significant figures. If there is a significant difference in the air flow between the front and back sides of the sample, calculate the arithmetic mean of the air permeability of each side separately. 8.3 Standard deviation
Repeat the test results and calculate its standard deviation or coefficient of variation, retaining two significant figures. 9 Test report
The test report shall include the following items:
a) This standard number:
b) The number of the tested pieces;
c) The range of the flow meter used;
d) If 1.47kPa is not used, the air pressure used shall be indicated;
e) The arithmetic mean of the test results;
f) The standard deviation or coefficient of variation of the test results;
g) Abnormalities during the test or operations that differ from this standard. 334
A1 Pressure regulating valve
GB/T 2679.13—1996
Appendix A
(Appendix to the standard)
Maintenance and maintenance of the Bentson instrument
The integrity of the pressure regulating valve shall be maintained, and its edges shall be avoided from being damaged when the pressure regulating valve is placed. The axial holes of the pressure regulating valve and the supporting valve shall be kept clean, without oil and dust, and lubricating oil shall not be added. First, let the air flow through, then put the pressure regulating valve on the shaft. The pressure regulating valve should be removed before stopping the air flow. A2 rotor flowmeter
For newly installed or reinstalled flowmeters after disassembly and cleaning, carefully check whether the rotor rotates freely. A rotor that does not rotate will affect the reading, especially at low flow rates. Check whether there are foreign objects brought into the flowmeter (such as instrument gaskets, particles that fall off the connecting pipe), otherwise it will affect the reading. Inspection method: Start the compressor, and after the air flow begins to flow, gently place the 1.47kPa pressure regulating valve on the shaft so that its rotation direction is consistent with the air flow direction of the axial hole, and the pressure regulating valve can rotate continuously and smoothly. Change the outlet valve of the flowmeter to change the outlet flow, and check whether the rotors of each flowmeter rotate smoothly and whether there are foreign objects entering the flowmeter with the air flow. If the rotor is found embedded in the bottom or top spring, and the rotor still cannot rotate freely after gently tapping the instrument when the airflow passes through the tube, you can use a special wrench to disassemble the round nuts at the bottom and top of the flowmeter, remove the metal block at the top, gently take out the flowmeter glass tube, remove foreign matter, and adjust the spring shape to prevent the rotor from being embedded again. The bottom spring should be limited to the concentric hole horizontal to the flowmeter, and the top spring should be limited to the concentric hole vertical to the flowmeter. If the flowmeter tube or rotor is dirty, the reading will be high. It can be cleaned with carbon tetrachloride and then dried with air flow. If it is washed with liquid detergent (10% aqueous solution), it should be cleaned with steamed stuffing water after washing and then dried with air flow. If the flowmeter tube is broken, it should be replaced.
All connecting tubes (rubber or plastic) should be checked regularly for wear and tear, and all tubes should be replaced once a year. A3 Pressure difference check
Use the connector to connect the (water column) pressure gauge and the corresponding capillary to the flow meter output. When the air flow rate is as follows, the pressure error should be within 5% of the ideal reading of the pressure gauge.
a) 10~150 mL/min rotor flowmeter:
Air flow, mL/min
Ideal reading of pressure gauge, mm
b) 50～~500mL/min rotor flowmeter: Air flow, mL/min
Ideal reading of pressure gauge, mm
c) 300～3000mL/min rotor flowmeter: 100
For air flow below 1200mL/min, the ideal reading of the pressure gauge is 150±10mm. To ensure that the test pressure drop is not too significant, the inner diameter of the pipe connecting the measuring head is 5~~6 mm and the length is not more than 600 mm. 335
B1 Calibration of flowmeter with capillary
GB/T 2679.13—1996
Appendix B
(Appendix of standard)
Calibration of capillary and flowmeter
The rotor of flowmeter is very sensitive to wear. If the scale reading differs from the specified value of the connected capillary by more than 5%, the following steps should be adopted:
B1.1 Calibrate two adjacent flowmeters with capillary. B1.2 If both readings are high, check the cleanliness of flowmeter and rotor and clean them if necessary. B1.3 If both readings are low, check the blockage of the system, such as folded pipes. B1.4 If the two readings are inconsistent, or B1.2 and B1.3 cannot determine the fault, calibrate the flowmeter with a soap bubble meter or other device at a pressure of 1.47 kPa.
B1.5 If the flowmeter or capillary is judged to be broken from the result of B1.4, it should be replaced. B2 Calibration of rotor flowmeter with soap bubble meter
B2.1 Instruments and materials
B2.1.1 Soap bubble meter
The soap bubble meter (Figure B1) consists of the following parts: a glass bottle with a volume of 1L;
a volume meter (carefully calibrated between two scales), with 100mL, 250mL and 1500mL scales, and different scale ranges can be obtained by reliably replacing the volume meter;
a needle valve (control valve).
B2.1.2 Stopwatch.
B2.1.3 Soap solution: 3% to 5% liquid detergent aqueous solution. B2.2 Calibration steps
Remove the measuring head at the outlet hose of the flowmeter and connect the hose to the soap bubble meter A. First, vent the air flow, then place the 1.47kPa pressure regulating valve on the shaft and rotate it. Open the vent valve, and the air flow is directed from the flow meter to the soap bubble meter for calibration. Carefully adjust the pipe clamp and the needle valve to make the flow of the flow meter constant. Quickly squeeze the rubber ball at the bottom of the volume meter to allow the soap bubble to enter the volume meter. Measure the time it takes for the soap bubble to pass between the two scales of the calibrated volume, expressed in seconds. The range of the selected volume meter should allow the measurement time to exceed 30s, repeat the measurement of 6 different air flows, and record the atmospheric pressure at that time.
GB/T2679.13-1996
A—Connection point; B—1L glass bottle; C—Needle valve; D Volume meter, E-Rubber ball Note: The system can produce calibration errors under high air flow pressure drop. In order to eliminate this error, the length and diameter of the tube must be the same as the test. Figure B1' Soap Bubble Meter
B2.3 Calculation
Check whether the reading error of the flow meter is within 5%. If not, a correction diagram can be drawn. Correct the air flow rate according to formula (B1) for each measurement time and measurement volume.
p×V× 60
102.8 X t
0. 584 p × V
.(B1)
- Air flow rate, expressed in mL/min, calibrated to 102.8 kPa conventional atmospheric pressure (101.3 kPa) and operating pressure at 23°C Where: 9—
pressure (1.47 kPa)";
Volume meter volume, mL,
Time for the soap bubble to pass between the two scales of the volume meter, sp—The sum of the actual atmospheric pressure and the (water column) pressure gauge, expressed in kPa. B3 Capillary Calibration
Connect the capillary between the outlet of the Bentsen flowmeter and point A of the soap bubble meter, and remove the control valve and the tube on the top of the volume meter. Measure the time for the soap bubble to pass through according to B2.2, and calculate the air flow according to B2.3. 33713—1996
Appendix A
(Standard Appendix)
Maintenance and Care of Bentsen Instruments
The integrity of the pressure regulating valve should be maintained, and its edge should be avoided from being damaged when the pressure regulating valve is placed. The axial holes of the pressure regulating valve and the supporting valve should be kept clean, without oil and dust, and lubricating oil should not be added. First, let the air flow through, then put the pressure regulating valve on the shaft, and remove the pressure regulating valve before stopping the air flow. A2 Rotor Flowmeter
For newly installed or reinstalled flowmeters after disassembly and cleaning, carefully check whether the rotor rotates freely. A non-rotating rotor will affect the reading, especially at low flow. Check whether there is any foreign matter brought into the flowmeter (such as particles from the instrument gasket and connecting pipe), otherwise it will affect the reading. Inspection method: Start the compressor, and after the air flow starts to flow, gently place the 1.47kPa pressure regulating valve on the shaft so that its rotation direction is consistent with the air flow direction of the axial hole, and the pressure regulating valve can rotate continuously and smoothly. Change the outlet valve of the flowmeter to change the outlet flow, and check whether the rotor of each flowmeter rotates smoothly and whether there is any foreign matter entering the flowmeter with the airflow. If the rotor is found to be embedded in the bottom or top spring, and the rotor still cannot rotate freely after gently tapping the instrument when the airflow passes through the tube, you can use a special wrench to disassemble the round nuts at the bottom and top of the flowmeter, remove the metal block at the top, gently take out the glass tube of the flowmeter, remove the foreign matter, and use the method of adjusting the shape of the spring to prevent the rotor from being embedded again. The bottom spring should be limited to the concentric hole horizontal to the flowmeter, and the top spring should be limited to the concentric hole vertical to the flowmeter. If the flowmeter tube or rotor is dirty, it will cause the reading to be high. It can be cleaned with carbon tetrachloride and then dried with air flow. If it is washed with liquid detergent (10% aqueous solution), it should be cleaned with steamed stuffing water after washing and then dried with air flow. If the flowmeter tube is broken, it should be replaced.
The wear of all connecting tubes (rubber or plastic) should be checked regularly, and all tubes should be replaced once a year. A3 Pressure difference check
Use the connector to connect the (water column) pressure gauge and the corresponding capillary to the flow meter output. When the air flow rate is as follows, the pressure error should be within 5% of the ideal reading of the pressure gauge.
a) 10~150 mL/min rotor flowmeter:
Air flow, mL/min
Ideal reading of pressure gauge, mm
b) 50～~500mL/min rotor flowmeter: Air flow, mL/min
Ideal reading of pressure gauge, mm
c) 300～3000mL/min rotor flowmeter: 100
For air flow below 1200mL/min, the ideal reading of the pressure gauge is 150±10mm. To ensure that the test pressure drop is not too significant, the inner diameter of the pipe connecting the measuring head is 5~~6 mm and the length is not more than 600 mm. 335
B1 Calibration of flowmeter with capillary
GB/T 2679.13—1996
Appendix B
(Appendix of standard)
Calibration of capillary and flowmeter
The rotor of flowmeter is very sensitive to wear. If the scale reading differs from the specified value of the connected capillary by more than 5%, the following steps should be adopted:
B1.1 Calibrate two adjacent flowmeters with capillary. B1.2 If both readings are high, check the cleanliness of flowmeter and rotor and clean them if necessary. B1.3 If both readings are low, check the blockage of the system, such as folded pipes. B1.4 If the two readings are inconsistent, or B1.2 and B1.3 cannot determine the fault, calibrate the flowmeter with a soap bubble meter or other device at a pressure of 1.47 kPa.
B1.5 If the flowmeter or capillary is judged to be broken from the result of B1.4, it should be replaced. B2 Calibration of rotor flowmeter with soap bubble meter
B2.1 Instruments and materials
B2.1.1 Soap bubble meter
The soap bubble meter (Figure B1) consists of the following parts: a glass bottle with a volume of 1L;
a volume meter (carefully calibrated between two scales), with 100mL, 250mL and 1500mL scales, and different scale ranges can be obtained by reliably replacing the volume meter;
a needle valve (control valve).
B2.1.2 Stopwatch.
B2.1.3 Soap solution: 3% to 5% liquid detergent aqueous solution. B2.2 Calibration steps
Remove the measuring head at the outlet hose of the flowmeter and connect the hose to the soap bubble meter A. First, vent the air flow, then place the 1.47kPa pressure regulating valve on the shaft and rotate it. Open the vent valve, and the air flow is directed from the flow meter to the soap bubble meter for calibration. Carefully adjust the pipe clamp and the needle valve to make the flow of the flow meter constant. Quickly squeeze the rubber ball at the bottom of the volume meter to allow the soap bubble to enter the volume meter. Measure the time it takes for the soap bubble to pass between the two scales of the calibrated volume, expressed in seconds. The range of the selected volume meter should allow the measurement time to exceed 30s, repeat the measurement of 6 different air flows, and record the atmospheric pressure at that time.
GB/T2679.13-1996
A—Connection point; B—1L glass bottle; C—Needle valve; D Volume meter, E-Rubber ball Note: The system can produce calibration errors under high air flow pressure drop. In order to eliminate this error, the length and diameter of the tube must be the same as the test. Figure B1' Soap Bubble Meter
B2.3 Calculation
Check whether the reading error of the flow meter is within 5%. If not, a correction diagram can be drawn. Correct the air flow rate according to formula (B1) for each measurement time and measurement volume.
p×V× 60
102.8 X t
0. 584 p × V
.(B1)
- Air flow rate, expressed in mL/min, calibrated to 102.8 kPa conventional atmospheric pressure (101.3 kPa) and operating pressure at 23°C Where: 9—
pressure (1.47 kPa)";
Volume meter volume, mL,
Time for the soap bubble to pass between the two scales of the volume meter, sp—The sum of the actual atmospheric pressure and the (water column) pressure gauge, expressed in kPa. B3 Capillary Calibration bzxZ.net
Connect the capillary between the outlet of the Bentsen flowmeter and point A of the soap bubble meter, and remove the control valve and the tube on the top of the volume meter. Measure the time for the soap bubble to pass through according to B2.2, and calculate the air flow according to B2.3. 33713—1996
Appendix A
(Standard Appendix)
Maintenance and Care of Bentsen Instruments
The integrity of the pressure regulating valve should be maintained, and its edge should be avoided from being damaged when the pressure regulating valve is placed. The axial holes of the pressure regulating valve and the supporting valve should be kept clean, without oil and dust, and lubricating oil should not be added. First, let the air flow through, then put the pressure regulating valve on the shaft, and remove the pressure regulating valve before stopping the air flow. A2 Rotor Flowmeter
For newly installed or reinstalled flowmeters after disassembly and cleaning, carefully check whether the rotor rotates freely. A non-rotating rotor will affect the reading, especially at low flow. Check whether there is any foreign matter brought into the flowmeter (such as particles from the instrument gasket and connecting pipe), otherwise it will affect the reading. Inspection method: Start the compressor, and after the air flow starts to flow, gently place the 1.47kPa pressure regulating valve on the shaft so that its rotation direction is consistent with the air flow direction of the axial hole, and the pressure regulating valve can rotate continuously and smoothly. Change the outlet valve of the flowmeter to change the outlet flow, and check whether the rotor of each flowmeter rotates smoothly and whether there is any foreign matter entering the flowmeter with the airflow. If the rotor is found to be embedded in the bottom or top spring, and the rotor still cannot rotate freely after gently tapping the instrument when the airflow passes through the tube, you can use a special wrench to disassemble the round nuts at the bottom and top of the flowmeter, remove the metal block at the top, gently take out the glass tube of the flowmeter, remove the foreign matter, and use the method of adjusting the shape of the spring to prevent the rotor from being embedded again. The bottom spring should be limited to the concentric hole horizontal to the flowmeter, and the top spring should be limited to the concentric hole vertical to the flowmeter. If the flowmeter tube or rotor is dirty, it will cause the reading to be high. It can be cleaned with carbon tetrachloride and then dried with air flow. If it is washed with liquid detergent (10% aqueous solution), it should be cleaned with steamed stuffing water after washing and then dried with air flow. If the flowmeter tube is broken, it should be replaced.
The wear of all connecting tubes (rubber or plastic) should be checked regularly, and all tubes should be replaced once a year. A3 Pressure difference check
Use the connector to connect the (water column) pressure gauge and the corresponding capillary to the flow meter output. When the air flow rate is as follows, the pressure error should be within 5% of the ideal reading of the pressure gauge.
a) 10~150 mL/min rotor flowmeter:
Air flow, mL/min
Ideal reading of pressure gauge, mm
b) 50～~500mL/min rotor flowmeter: Air flow, mL/min
Ideal reading of pressure gauge, mm
c) 300～3000mL/min rotor flowmeter: 100
For air flow below 1200mL/min, the ideal reading of the pressure gauge is 150±10mm. To ensure that the test pressure drop is not too significant, the inner diameter of the pipe connecting the measuring head is 5~~6 mm and the length is not more than 600 mm. 335
B1 Calibration of flowmeter with capillary
GB/T 2679.13—1996
Appendix B
(Appendix of standard)
Calibration of capillary and flowmeter
The rotor of flowmeter is very sensitive to wear. If the scale reading differs from the specified value of the connected capillary by more than 5%, the following steps should be adopted:
B1.1 Calibrate two adjacent flowmeters with capillary. B1.2 If both readings are high, check the cleanliness of flowmeter and rotor and clean them if necessary. B1.3 If both readings are low, check the blockage of the system, such as folded pipes. B1.4 If the two readings are inconsistent, or B1.2 and B1.3 cannot determine the fault, calibrate the flowmeter with a soap bubble meter or other device at a pressure of 1.47 kPa.
B1.5 If the flowmeter or capillary is judged to be broken from the result of B1.4, it should be replaced. B2 Calibration of rotor flowmeter with soap bubble meter
B2.1 Instruments and materials
B2.1.1 Soap bubble meter
The soap bubble meter (Figure B1) consists of the following parts: a glass bottle with a volume of 1L;
a volume meter (carefully calibrated between two scales), with 100mL, 250mL and 1500mL scales, and different scale ranges can be obtained by reliably replacing the volume meter;
a needle valve (control valve).
B2.1.2 Stopwatch.
B2.1.3 Soap solution: 3% to 5% liquid detergent aqueous solution. B2.2 Calibration steps
Remove the measuring head at the outlet hose of the flowmeter and connect the hose to the soap bubble meter A. First, vent the air flow, then place the 1.47kPa pressure regulating valve on the shaft and rotate it. Open the vent valve, and the air flow is directed from the flow meter to the soap bubble meter for calibration. Carefully adjust the pipe clamp and the needle valve to make the flow of the flow meter constant. Quickly squeeze the rubber ball at the bottom of the volume meter to allow the soap bubble to enter the volume meter. Measure the time it takes for the soap bubble to pass between the two scales of the calibrated volume, expressed in seconds. The range of the selected volume meter should allow the measurement time to exceed 30s, repeat the measurement of 6 different air flows, and record the atmospheric pressure at that time.
GB/T2679.13-1996
A—Connection point; B—1L glass bottle; C—Needle valve; D Volume meter, E-Rubber ball Note: The system can produce calibration errors under high air flow pressure drop. In order to eliminate this error, the length and diameter of the tube must be the same as the test. Figure B1' Soap Bubble Meter
B2.3 Calculation
Check whether the reading error of the flow meter is within 5%. If not, a correction diagram can be drawn. Correct the air flow rate according to formula (B1) for each measurement time and measurement volume.
p×V× 60
102.8 X t
0. 584 p × V
.(B1)
- Air flow rate, expressed in mL/min, calibrated to 102.8 kPa conventional atmospheric pressure (101.3 kPa) and operating pressure at 23°C Where: 9—
pressure (1.47 kPa)";
Volume meter volume, mL,
Time for the soap bubble to pass between the two scales of the volume meter, sp—The sum of the actual atmospheric pressure and the (water column) pressure gauge, expressed in kPa. B3 Capillary Calibration
Connect the capillary between the outlet of the Bentsen flowmeter and point A of the soap bubble meter, and remove the control valve and the tube on the top of the volume meter. Measure the time for the soap bubble to pass through according to B2.2, and calculate the air flow according to B2.3. 337
Air flow, mL/min
Ideal pressure gauge reading, mm
b) 50～~500mL/min rotor flowmeter: Air flow, mL/min
Ideal pressure gauge reading, mm
c) 300～3000mL/min rotor flowmeter: 100
For air flow below 1200mL/min, the ideal pressure gauge reading is 150±10mm. In order to ensure that the test pressure drop is not too significant, the inner diameter of the pipe connecting the measuring head is 5~~6 mm and the length is not more than 600 mm. 335
B1 Calibration of flowmeter with capillary
GB/T 2679.13—1996
Appendix B
(Appendix of standard)
Calibration of capillary and flowmeter
The rotor of flowmeter is very sensitive to wear. If the scale reading differs from the specified value of the connected capillary by more than 5%, the following steps should be adopted:
B1.1 Calibrate two adjacent flowmeters with capillary. B1.2 If both readings are high, check the cleanliness of flowmeter and rotor and clean them if necessary. B1.3 If both readings are low, check the blockage of the system, such as folded pipes. B1.4 If the two readings are inconsistent, or B1.2 and B1.3 cannot determine the fault, calibrate the flowmeter with a soap bubble meter or other device at a pressure of 1.47 kPa.
B1.5 If the flowmeter or capillary is judged to be broken from the result of B1.4, it should be replaced. B2 Calibration of rotor flowmeter with soap bubble meter
B2.1 Instruments and materials
B2.1.1 Soap bubble meter
The soap bubble meter (Figure B1) consists of the following parts: a glass bottle with a volume of 1L;
a volume meter (carefully calibrated between two scales), with 100mL, 250mL and 1500mL scales, and different scale ranges can be obtained by reliably replacing the volume meter;
a needle valve (control valve).
B2.1.2 Stopwatch.
B2.1.3 Soap solution: 3% to 5% liquid detergent aqueous solution. B2.2 Calibration steps
Remove the measuring head at the outlet hose of the flowmeter and connect the hose to the soap bubble meter A. First, vent the air flow, then place the 1.47kPa pressure regulating valve on the shaft and rotate it. Open the vent valve, and the air flow is directed from the flow meter to the soap bubble meter for calibration. Carefully adjust the pipe clamp and the needle valve to make the flow of the flow meter constant. Quickly squeeze the rubber ball at the bottom of the volume meter to allow the soap bubble to enter the volume meter. Measure the time it takes for the soap bubble to pass between the two scales of the calibrated volume, expressed in seconds. The range of the selected volume meter should allow the measurement time to exceed 30s, repeat the measurement of 6 different air flows, and record the atmospheric pressure at that time.
GB/T2679.13-1996
A—Connection point; B—1L glass bottle; C—Needle valve; D Volume meter, E-Rubber ball Note: The system can produce calibration errors under high air flow pressure drop. In order to eliminate this error, the length and diameter of the tube must be the same as the test. Figure B1' Soap Bubble Meter
B2.3 Calculation
Check whether the reading error of the flow meter is within 5%. If not, a correction diagram can be drawn. Correct the air flow rate according to formula (B1) for each measurement time and measurement volume.
p×V× 60
102.8 X t
0. 584 p × V
.(B1)
- Air flow rate, expressed in mL/min, calibrated to 102.8 kPa conventional atmospheric pressure (101.3 kPa) and operating pressure at 23°C Where: 9—
pressure (1.47 kPa)";
Volume meter volume, mL,
Time for the soap bubble to pass between the two scales of the volume meter, sp—The sum of the actual atmospheric pressure and the (water column) pressure gauge, expressed in kPa. B3 Capillary Calibration
Connect the capillary between the outlet of the Bentsen flowmeter and point A of the soap bubble meter, and remove the control valve and the tube on the top of the volume meter. Measure the time for the soap bubble to pass through according to B2.2, and calculate the air flow according to B2.3. 337
Air flow, mL/min
Ideal pressure gauge reading, mm
b) 50～~500mL/min rotor flowmeter: Air flow, mL/min
Ideal pressure gauge reading, mm
c) 300～3000mL/min rotor flowmeter: 100
For air flow below 1200mL/min, the ideal pressure gauge reading is 150±10mm. In order to ensure that the test pressure drop is not too significant, the inner diameter of the pipe connecting the measuring head is 5~~6 mm and the length is not more than 600 mm. 335
B1 Calibration of flowmeter with capillary
GB/T 2679.13—1996
Appendix B
(Appendix of standard)
Calibration of capillary and flowmeter
The rotor of flowmeter is very sensitive to wear. If the scale reading differs from the specified value of the connected capillary by more than 5%, the following steps should be adopted:
B1.1 Calibrate two adjacent flowmeters with capillary. B1.2 If both readings are high, check the cleanliness of flowmeter and rotor and clean them if necessary. B1.3 If both readings are low, check the blockage of the system, such as folded pipes. B1.4 If the two readings are inconsistent, or B1.2 and B1.3 cannot determine the fault, calibrate the flowmeter with a soap bubble meter or other device at a pressure of 1.47 kPa.
B1.5 If the flowmeter or capillary is judged to be broken from the result of B1.4, it should be replaced. B2 Calibration of rotor flowmeter with soap bubble meter
B2.1 Instruments and materials
B2.1.1 Soap bubble meter
The soap bubble meter (Figure B1) consists of the following parts: a glass bottle with a volume of 1L;
a volume meter (carefully calibrated between two scales), with 100mL, 250mL and 1500mL scales, and different scale ranges can be obtained by reliably replacing the volume meter;
a needle valve (control valve).
B2.1.2 Stopwatch.
B2.1.3 Soap solution: 3% to 5% liquid detergent aqueous solution. B2.2 Calibration steps
Remove the measuring head at the outlet hose of the flowmeter and connect the hose to the soap bubble meter A. First, vent the air flow, then place the 1.47kPa pressure regulating valve on the shaft and rotate it. Open the vent valve, and the air flow is directed from the flow meter to the soap bubble meter for calibration. Carefully adjust the pipe clamp and the needle valve to make the flow of the flow meter constant. Quickly squeeze the rubber ball at the bottom of the volume meter to allow the soap bubble to enter the volume meter. Measure the time it takes for the soap bubble to pass between the two scales of the calibrated volume, expressed in seconds. The range of the selected volume meter should allow the measurement time to exceed 30s, repeat the measurement of 6 different air flows, and record the atmospheric pressure at that time.
GB/T2679.13-1996
A—Connection point; B—1L glass bottle; C—Needle valve; D Volume meter, E-Rubber ball Note: The system can produce calibration errors under high air flow pressure drop. In order to eliminate this error, the length and diameter of the tube must be the same as the test. Figure B1' Soap Bubble Meter
B2.3 Calculation
Check whether the reading error of the flow meter is within 5%. If not, a correction diagram can be drawn. Correct the air flow rate according to formula (B1) for each measurement time and measurement volume.
p×V× 60
102.8 X t
0. 584 p × V
.(B1)
- Air flow rate, expressed in mL/min, calibrated to 102.8 kPa conventional atmospheric pressure (101.3 kPa) and operating pressure at 23°C Where: 9—
pressure (1.47 kPa)";
Volume meter volume, mL,
Time for the soap bubble to pass between the two scales of the volume meter, sp—The sum of the actual atmospheric pressure and the (water column) pressure gauge, expressed in kPa. B3 Capillary Calibration
Connect the capillary between the outlet of the Bentsen flowmeter and point A of the soap bubble meter, and remove the control valve and the tube on the top of the volume meter. Measure the time for the soap bubble to pass through according to B2.2, and calculate the air flow according to B2.3. 337
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