JB/T 4278.6-1993 Rubber and plastic wire and cable test equipment verification method Natural ventilation thermal aging test chamber
Some standard content:
ICS29.060
Registration No.: 32039—2011
Mechanical Industry Standard of the People's Republic of China
JB/T4278.6—2011
Replaces JB/T4278.61993
Verification procedure for test equipment of rubber plastic wire and cablePart6:Natural ventilation thermalaging test oven2011-05-18 Issued
2011-08-01 Implementation
The Ministry of Industry and Information Technology of the People's Republic of China Issued ForewordwwW.bzxz.Net
Normative references
Verification items and technical requirements
Verification equipment..
Verification method
Determination of ventilation rate
5.3 Verification of test chamber 1 as work space
Calculation of verification results.
6.1 Calculation of ventilation rate.| |tt||6.2 Calculation of temperature deviation,
Processing of verification results,
Appendix A (Informative Appendix) Original record of ventilation frequency test of aging test chamber Appendix B (Informative Appendix) Test chamber temperature test record Appendix C (Normative Appendix) Sample table of verification certificate contents 1
Air density
JB/T4278.6—2011
JB/T4278 "Verification methods for rubber and plastic wire and cable test instruments and equipment" is divided into 19 parts : Part 1: General:
Part 2: Low temperature impact test device:
- Part 3: Flexure test device:
Part 4: Abrasion test device:
Part 5: Vertical combustion test device for single insulated wires and cables: Part 6: Natural ventilation heat aging test chamber: Part 7: Constant temperature water bath;
Part 8: Low temperature test chamber:
Part 9: Oxygen bomb, air bomb aging test chamber; - Part 10: Spark test Machine:
Part 11: Low temperature winding test machine;
Part 12: High temperature pressure test device: Part 13: Forced ventilation heat aging test chamber; Part 14: Fire resistance test device:
Part 15: Bundled combustion test device: Part 16: Smoke density test device;
Part 17: Carbon black content test device: Part 18: Single copper core insulated thin wire and cable multiplied by straight combustion test device: Part 19: Insulation scratch resistance tester. This part is Part 6 of JB/T4278.
JB/T4278.6--2011
This part replaces JB/T4278.6-1993 "Verification methods for rubber and plastic wire and cable test equipment Part 6: Natural ventilation heat aging test chamber".
Compared with JB/T4278.6-1993, the main changes of this part are as follows: the temperature deviation is changed from "shall comply with the wire and cable test method standard" to "shall comply with the temperature deviation in the wire and cable product standard" (3.3 of this edition, 3.2 of the 1993 edition); the verification cycle of the aging test chamber is changed from "2 years" to "1 year" (7.5 of this edition, 6.7 of the 1993 edition). Appendix A and Appendix B of this part are informative appendices, and Appendix C is a normative appendix. This part is proposed by the China Machinery Federation. This part is under the jurisdiction of the National Wire and Cable Standardization Technical Committee (SAC/TC213). Drafting units of this part: Shanghai Cable Research Institute, Shanghai Huapu Cable Co., Ltd., Wuxi Yongling Electronic and Electrical Equipment Co., Ltd. The main drafters of this part: Fan Hongxin, Liu Enju, Zhang Mingjie, Zhang Weijun. The previous versions of the standard replaced by this part are: JB4278.6-1986, JB/T4278.6-1993. 1 Scope
Verification methods for rubber and plastic wire and cable test equipment Part 6: Natural ventilation thermal aging test chamber JB/T4278.6-2011
This part of JB/T4278 specifies the verification items and technical requirements, verification instruments, verification methods, verification results and processing of natural ventilation thermal aging test chambers.
This part is applicable to the determination of the number of air changes and the verification of the working space in the natural ventilation thermal aging test chamber for wires and cables. 2 Normative references
The clauses in the following documents become the clauses of this part through reference in this part of JB/T4278. For any referenced document with an H date, all subsequent amendments (excluding errata) or revisions are not applicable to this part. However, parties to an agreement based on this part are encouraged to study whether the latest versions of these documents can be used. For any referenced document without an H date, the latest version shall apply to this part.
JB/T4278.1-2011 Verification methods for rubber and plastic wire and cable test equipment Part 1: General 3 Verification items and technical requirements
The technical requirements of the natural ventilation heat aging test chamber shall comply with the provisions of JB/T4278.1-2011 in addition to the provisions of this part. 3.2 At the specified test temperature, the total air replacement frequency in the chamber shall be (8 to 20) times/h. 3.3 The temperature deviation of the working space of the natural ventilation heat aging test chamber shall comply with the provisions on temperature deviation in the wire and cable product standards. 4 Calibration instruments
4.1 Thermocouple group: A thermocouple group is composed of 9 thermocouples of nickel-chromium-copper-nickel (constantan), nickel-chromium-nickel silicon or other materials with a wire diameter of 0.5mm and a node diameter of not more than 2.0mm. The 9 thermocouples should be composed of wires of the same spool so that the difference in thermoelectric potential between them when converted into a temperature difference below 200℃ is not more than 0.2℃. 4.2 DC digital voltmeter: The actual measurement deviation is less than 0.05%. When using nickel-chromium-copper-nickel (constantan) thermocouples, the resolution of the digital voltmeter is not less than 10uV; when using other thermocouples, the resolution of the digital voltmeter is not less than 1μV. 4.3 Thermocouple conversion switch.
4.4 Single-phase standard electric energy meter or digital power meter: 0.5 level. 4.5 Standard mercury thermometer: second level.
4.6 Stopwatch: graduation value 0.1s.
5 Verification method
5.1 Procedure
5.1.1 Determine the ventilation frequency of the test chamber.
5.1.2 Verify the working space of the test chamber.
5.2 Determination of ventilation frequency
5.2.1 Close all ventilation openings of the test chamber. Use adhesive tape to seal the door, air inlet and outlet, thermometer socket and other parts where air exchange between the inside and outside of the chamber is possible.
5.2.2 Place a standard mercury thermometer at the geometric center of the test chamber to observe the temperature in the test chamber and adjust the temperature of the test chamber to within ±2°C of the required temperature of the test. After the temperature in the chamber is balanced, keep the temperature constant for 1 hour. 5.2.3 Use a standard electric energy meter to measure the power consumption of the heater of the test chamber in a sealed state for 0.5 hour or more, and convert it into average power P1. The start and end of the two-position control heater test chamber should be measured at the corresponding points of the "on-off" heating cycle of the test chamber. 5.2.4 Remove the sealing tape, adjust the position of the inlet and outlet vents, and keep the temperature constant for 1 hour after the temperature in the chamber is balanced. Use the same method to measure the power consumption of the test chamber heater in the unsealed state and convert it into average power P25.2.5 Measure the ambient temperature at a distance of about 2m from the test chamber, at a position approximately horizontal to the bottom of the test chamber, and at least 0.6m away from any physical object. The difference between the temperature inside the chamber and the ambient temperature should be the same in the two states of the test chamber, and the error should be less than 0.2℃. 5.2.6 After the measurement, calculate according to 6.1. If the ventilation frequency of the test chamber does not meet the test conditions, the position of the inlet and outlet vents can be readjusted and measured according to the method of 5.2.4.
5.2.7 If the ventilation frequency of the test chamber still does not meet the requirements of 3.2 under the extreme conditions of the position of the inlet and outlet vents, the test chamber is unqualified and no further verification of the working space is required. 5.2.8 For the original record of the ventilation frequency test, please refer to Appendix A. 5.3 Verification of the working space of the test chamber
5.3.11. The working space is called the measured space during the verification process. The measured space is located near the center of the test chamber, and its interface is parallel to the interface of the space inside the chamber. Its height is not less than 150mm, and its length and width are generally (200~250)mm. The geometric center point of the measured space should not deviate from the temperature sensing end of the thermometer indicating the test temperature of the test chamber by 25mm. 5.3.2 Use 9 thermocouples to measure the temperature of 9 measuring points in the measured space, 1 measuring point is the center point of the measured space, and the other 8 measuring points are the 8 vertices of the measured space. The length of the thermocouple at each measuring point in the test chamber is not less than 300mm. 5.3.3 Adjust the temperature of the test chamber so that the temperature of the test chamber does not deviate from the required temperature of the test by ±2°C. 5.3.4 Start measuring 1 hour after the test chamber reaches thermal stability, and quickly record the thermoelectric potential of the thermocouples at the 9 measuring points. Measure once every 5 minutes (0th minute, 5th minute, 10th minute, 15th minute, 20th minute), and complete 5 measurements. 5.3.5 See Appendix B for the test chamber temperature test record. 6 Calculation of verification results
6.1 Calculation of ventilation frequency
Calculate the ventilation frequency N of the test chamber per hour according to formula (1): N
Wherein:
3590(PP)
Vd(T,-T,)
N Ventilation frequency, in times per hour (times/h); P.
Average power when the valve is closed, in watts (W); P2
Average power when the valve is open, in watts (W): Ti
Ambient temperature, in degrees Celsius (℃): T2
Temperature inside the chamber, in degrees Celsius (℃); Volume occupied by the air in the test chamber, in liters (L); Density of the ambient air during the test, in grams per liter (g/), see Table 1. Table 1
Air density
·（1）
6.2 Calculation of temperature deviation
6.2.1 Calculation of spatial temperature deviation
Table 1 (continued)
JB/T4278.6——2011
Calculate the average value of the incandescent electromotive force of 9 measuring points for 5 measurements respectively, and convert it into the average temperature of each measuring point by looking up the graduation table. Taking the average temperature of the center point of the measured space as the reference, calculate the spatial temperature deviation of the average temperature of each measuring point and the average temperature of the center point according to formula (2) (accurate to 0.1℃):
Where:
--Spatial temperature deviation of the first vertex of the measured space (T1～8), in degrees Celsius (℃); T---Average temperature of the ith vertex of the measured space (18), in degrees Celsius (℃);--Average temperature of the center point of the measured space, in degrees Celsius (℃). To
6.2.2 Calculation of time temperature fluctuation
According to formula (3), calculate the difference between the highest temperature and the lowest temperature of each of the 8 vertices in the measured space in 5 measurements, and obtain the time temperature fluctuation of the measured space (accurate to 0.1℃):
b,=bamax-bimir
Wherein:
Time temperature fluctuation of the first vertex (=1~8), in degrees Celsius (℃): The highest temperature of the i-th vertex (1~8), in degrees Celsius (℃); The lowest temperature of the i-th vertex (=1~8), in degrees Celsius (℃). 6.2.3 Calculation of temperature deviation
The temperature deviation is the combination of spatial temperature deviation and time temperature fluctuation. The temperature deviation is calculated according to formula (4) (accurate to 0.1°C): b,
AT, =a, +
Where:
i-th vertex temperature deviation (1～8), unit is Celsius (°C); i-th vertex spatial temperature deviation (=1～8), unit is Celsius (°C); b-i-th vertex time temperature fluctuation (1～8), unit is Celsius (°C). 7 Processing of verification results
7.1 Check the calculation results of 6.2.3 (keep 1 significant figure). If the maximum temperature deviation meets the requirements of 3.3, the measured space is the working space.
7.2 Check the calculation results. If the temperature deviation of the measured space does not meet the requirements of the wire and cable product standards, the position of the measured space in the test chamber can be changed or the measured space can be changed to a smaller size and then retested. In order to ensure that the thermocouple at the original center of the measured space does not exceed 25 mm from the temperature sensing end of the thermometer due to the change of the measured space, the position of the thermocouple can be slightly moved. At this time, the thermocouple at this measuring point can no longer be located at the center of the measured space after the change. 7.3 This verification method does not include the verification of the test chamber test temperature indicating instrument (or thermometer). For a test chamber where the test temperature is displayed by a temperature indicating instrument and the temperature sensing element of the instrument cannot be located at the center of the working space, the deviation between the temperature indicator value indicated at the verification temperature and the actual temperature at the center of the working space should be given in the verification results. 7.4 A verification certificate shall be issued to the qualified test chamber, and a verification result notice shall be issued to the unqualified test chamber. The content of the calibration certificate is shown in Appendix C. The certificate should indicate the base temperature, the location of the air inlet and outlet holes, and the temperature and use of the working space. The calibration cycle of the natural ventilation heat aging test chamber is generally set at 1 year. 7.5
Inspection unit:
Test piece model:
Test piece manufacturer:
Test temperature (℃):
Appendix A
(Informative Appendix)
Original record of ventilation frequency test of aging test chamberTest date:
Test piece name:
Factory number:
Test chamber size (length × width × height) (mm):Thermocouple model and number:
Test instrument model and number:
Measurement of chamber ventilation:
Test chamber
Test chamber
Wind sheath position
The ventilation times N of the test chamber is calculated as follows:
Wherein: V=
Test results: Wind width position
Room temperature:
℃: Humidity:
Cold end temperature (℃):
Standard electric energy meter
Number of doors (5A)
3590(PP）
Vd(T,-T)
Ventilation times
%: Test:
Verification:
Temperature inside the chamber
JB/T4278.6-2011=a, +
Wherein:
i-th vertex temperature deviation (1～8), in degrees Celsius (℃); i-th vertex space temperature deviation (=1～8), in degrees Celsius (℃); b—i-th vertex time temperature fluctuation (1～8), in degrees Celsius (℃). 7 Processing of verification results
7.1 Check the calculation results of 6.2.3 (keep 1 significant digit). If the maximum temperature deviation meets the requirements of 3.3, the measured space is the working space.
7.2 Check the calculation results. If the temperature deviation of the measured space does not meet the requirements of the wire and cable product standards, the position of the measured space in the 3
JB/T4278.6--2011
test box can be changed or the number of people in the measured space can be changed and retested. In order to ensure that the thermocouple at the original center point of the measured space will not exceed 25mm from the temperature sensing end of the thermometer due to the change of the measured space, the position of this thermocouple can be slightly moved. At this time, the thermocouple at this measuring point can no longer be located at the center of the measured space after the change. 7.3 This verification method does not include the verification of the test temperature indicating instrument (or thermometer) of the test chamber. For the test chamber where the test temperature is displayed by the temperature indicating instrument and the temperature sensing element of the instrument cannot be located at the center of the working space, the deviation between the value indicated by the temperature indicator at the verification temperature and the actual temperature at the center of the working space should be given in the verification result. 7.4 A verification certificate shall be issued to the test chamber that passes the verification, and a verification result notice shall be issued to the unqualified one. The content of the verification certificate is shown in Appendix C. The certificate shall indicate the base temperature, the location of the inlet and outlet vents, and the temperature and use of the working space. The verification cycle of the natural ventilation heat aging test chamber is generally set at 1 year. 7.5
Inspection unit:
Test piece model:
Test piece manufacturer:
Test temperature (℃):
Appendix A
(Informative Appendix)
Original record of ventilation frequency test in aging test chamberTest date:
Test piece name:
Factory number:
Test chamber dimensions (length × width × height) (mm):Thermocouple model and number:
Test instrument model and number:
Measurement of ventilation in test chamber:
Test chamber
Test chamber
Wind sheath position
The ventilation times N of the test chamber is calculated as follows:
Wherein: V=
Test results: Wind width position
Room temperature:
℃: Humidity:
Cold end temperature (℃):
Standard electric energy meter
Number of doors (5A)
3590(PP）
Vd(T,-T)
Ventilation times
%: Test:
Verification:
Temperature inside the chamber
JB/T4278.6-2011=a, +
Wherein:
i-th vertex temperature deviation (1～8), in degrees Celsius (℃); i-th vertex space temperature deviation (=1～8), in degrees Celsius (℃); b—i-th vertex time temperature fluctuation (1～8), in degrees Celsius (℃). 7 Processing of verification results
7.1 Check the calculation results of 6.2.3 (keep 1 significant digit). If the maximum temperature deviation meets the requirements of 3.3, the measured space is the working space.
7.2 Check the calculation results. If the temperature deviation of the measured space does not meet the requirements of the wire and cable product standards, the position of the measured space in the 3
JB/T4278.6--2011
test box can be changed or the number of people in the measured space can be changed and retested. In order to ensure that the thermocouple at the original center point of the measured space will not exceed 25mm from the temperature sensing end of the thermometer due to the change of the measured space, the position of this thermocouple can be slightly moved. At this time, the thermocouple at this measuring point can no longer be located at the center of the measured space after the change. 7.3 This verification method does not include the verification of the test temperature indicating instrument (or thermometer) of the test chamber. For the test chamber where the test temperature is displayed by the temperature indicating instrument and the temperature sensing element of the instrument cannot be located at the center of the working space, the deviation between the value indicated by the temperature indicator at the verification temperature and the actual temperature at the center of the working space should be given in the verification result. 7.4 A verification certificate shall be issued to the test chamber that passes the verification, and a verification result notice shall be issued to the unqualified one. The content of the verification certificate is shown in Appendix C. The certificate shall indicate the base temperature, the location of the inlet and outlet vents, and the temperature and use of the working space. The verification cycle of the natural ventilation heat aging test chamber is generally set at 1 year. 7.5
Inspection unit:
Test piece model:
Test piece manufacturer:
Test temperature (℃):
Appendix A
(Informative Appendix)
Original record of ventilation frequency test in aging test chamberTest date:
Test piece name:
Factory number:
Test chamber dimensions (length × width × height) (mm):Thermocouple model and number:
Test instrument model and number:
Measurement of ventilation in test chamber:
Test chamber
Test chamber
Wind sheath position
The ventilation times N of the test chamber is calculated as follows:
Wherein: V=
Test results: Wind width position
Room temperature:
℃: Humidity:
Cold end temperature (℃):
Standard electric energy meter
Number of doors (5A)
3590(PP）
Vd(T,-T)
Ventilation times
%: Test:
Verification:
Temperature inside the chamber
JB/T4278.6-2011
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