Some standard content:
Machinery Industry Standard of the People's Republic of China
JB/T6804-93
Vibration-resistant pressure gauge
Published on July 9, 1993
Implementation on January 1, 1994
Published by the Ministry of Machinery Industry of the People's Republic of China 1 Subject content and scope of application
Machinery Industry Standard of the People's Republic of China
Vibration-resistant pressure gauge
JB/T680493
This standard specifies the product classification, technical requirements, test methods, inspection rules, as well as marking, packaging and storage of vibration-resistant pressure gauges. This standard applies to direct indicating pressure gauges with filling liquid and dampers in the case; it also applies to direct indicating pressure gauges with filling liquid in the case (hereinafter referred to as instruments). 2 Reference standards
GB4439
GB4451
JB/5528
ZBY002
ZBY003
3 Terms
Working conditions of industrial automation instruments - vibration Industrial automation instruments Vibration (sinusoidal) test method Pressure gauge scale and division
Basic environmental conditions and test methods for transportation and storage of instruments and meters General technical conditions for instrument and meter packagingwww.bzxz.net
Decrement ratio
The ratio of the actual indicated pressure change amplitude of the instrument to the input pressure change amplitude. Pulsation error
The difference between the median value of the actual indicated pressure change range of the instrument and the median value of the input pressure change range. 4 Product classification
4.1 The instrument is divided into two types: the case is filled with filling liquid and the case is filled with filling liquid and has a damper. 4.2 Nominal diameter of the instrument shell:
60;100;150;200mms
4.3 The accuracy level of the instrument is divided into:
1.5;2.5;4.0.
4.4 The scale and division of the meter shall comply with the provisions of JB/T5528. 4.5 The thread of the instrument connector:
M14×1.5;M20×1.5;R1.5;R2.
Note: If the user has special requirements for the product classification regulations, they can negotiate with the manufacturer. 5 Technical requirements
5.1 Normal working conditions
5.1.1 Instrument working environment temperature:
Approved by the Ministry of Machinery Industry on July 9, 1993
Implemented on January 1, 1994
JB/T6804-93
Only for the instrument working environment temperature in one of the following two temperature ranges -5~55℃ and -25～55℃.
5.1.2 Instrument working vibration conditions:
The instrument working vibration conditions shall not exceed the two vibration levels of V·H·4 and V·H·5 specified in GB4439 -5.1.3 The instrument is generally used to 3/4 of the upper limit of the measurement. Note: The working environment temperature and vibration level selected for different types of instruments must be clearly stated in the enterprise standard or product manual. 5.2 Reference working conditions
Under the following conditions, the basic error, back-and-forth error, tapping displacement, and pointer deflection stability of the instrument shall comply with the provisions of the relevant clauses. a. The instrument is in the normal working position (if not specified, the normal working position refers to vertical installation); b. The load is stable and the change should be uniform when increasing or decreasing the load; c. The ambient temperature is 20±5℃.
5.3 Basic error
The basic error of the instrument is expressed as the reference error, and its value should be within the range specified in Table 1. Table 1
Accuracy
Upper limit of measurement
Less than 10%
Basic error limit (upper limit of measurement %)
Upper limit of measurement
10%~90%
Note: The accuracy level of the instrument is determined by the basic error limit within the range of 10% to 90% of the upper limit of measurement. 5.4 Back-and-forth error
The back-and-forth error of the instrument should not be greater than the absolute value of the basic error limit. 5.5 Tap displacement
Measurement upper limit
90% or more
At any position within the measurement range, tap the case to make the pointer or dial swing freely. The change in the indicated value should not be greater than the absolute value of the basic error limit.
5.6 Pointer deflection stability
During the measurement process, the pointer or dial of the instrument should not jump or stagnate. 5.7 Overload
The instrument should withstand an overload test of 30 minutes as specified in Table 2. After the test, it should meet the requirements of Articles 5.3 to 5.6. Table 2
Upper limit of measurement MPa
>60~100
5.8 Influence of temperature
Load (upper limit of measurement %)
When the ambient temperature deviates from 20±5℃, the indication error of the instrument shall not be greater than the range specified in the following formula:△≤±(8+K△t)
The allowable value of indication error when the ambient temperature deviates from 20±5℃ is expressed in the same way as the basic error, %; where—
The absolute value of the basic error limit specified in Article 5.3 of this standard, %; At-tt, C;
Any temperature value of the instrument within the temperature range selected in Article 5.1.1 of this standard; t2
When t2 is higher than 25℃, it is 25℃; when tz is lower than 15℃, it is 15℃; JB/T6804-93
K——When the elastic element is a fork spring, its value is 0.16%/℃. When the elastic element is a spring tube: the spring tube is filled with filling liquid, and its value is 0.1%/℃; the spring tube is not filled with filling liquid, and its value is 0.04%/℃. 5.9 Resistance to pulsation of the measured medium
This clause applies to instruments with dampers. When the load is pulsating pressure:
a, the reduction ratio of the instrument is not greater than 0.5;
b. The pulsation error of the instrument is not greater than twice the basic error limit. 5.10 Alternating load
The instrument shall withstand the alternating load test of the sine waveform as specified in Table 3. After the test, it shall comply with the provisions of 5.3 to 5.6. Table 3
Measurement upper limit MPa
>60~100
5.11 Anti-working environment vibration
Alternating amplitude (measurement upper limit %)
The vibration level that the instrument can withstand should be selected from V·H·4 and V·H·5 specified in GB4439. The indication error of the instrument in vibration according to the selected vibration level should not be greater than three times the basic error limit. After the test, the instrument should still meet the requirements of Articles 5.3 to 5.6. 5.12 Anti-transport environment performance
The instrument should meet the requirements of ZBY002 under the conditions of transportation packaging. Among them: a. High temperature and relative humidity items are exempted;
b. Low temperature is -40℃;
c. Free fall height is 250mm.
After the test, it should meet the requirements of Articles 5.3 to 5.6. 5.13 Case sealing
After the filling liquid is injected into the case of the instrument, there should be no leakage. 5.14 Appearance
The visible part of the instrument should be free of obvious flaws and scratches, and the joint thread should be free of obvious burrs and damage. All signs, numbers, words and symbols should be clear and correct.
6 Test method
For the test sequence and the interval time between items, see Appendix A (Supplement). 6.1 Test conditions
6.1.1 Temperature
According to the reference working conditions in 5.2.
Note: ①Factory inspection may not be carried out under the reference temperature conditions, but the instrument shall still comply with the provisions of Article 5.35.6 of this standard under the reference working conditions.
②For damping adjustable instruments, the test should be carried out under a certain value of the reduction ratio within the range of 0.30 to 0.35. During the test, the damper shall not be adjusted.
6.1.2 Standard instrument
The absolute value of the absolute error allowable value of the standard instrument used shall not be greater than 1/3 of the absolute value of the absolute error allowable value of the instrument being measured.6.1.3 Inspection point
The scale line marked with numbers shall be used as the inspection point.3
6.1.4 Inspection method
JB/T6804-93
Inspection shall be conducted by comparing the instrument with the standard instrument.6.2 Basic error inspection
6.2.1 During inspection, the load shall be increased steadily from zero point, and the specified inspection point shall be inspected to the upper limit of measurement, and maintained for 3 minutes, and then the load shall be reduced steadily. Each inspection point shall be inspected to zero point.
6.2.2 The basic error shall be inspected once before and after tapping in the forward and reverse travel. The reading shall be made after the indication is stable, and the indication after tapping shall not exceed the provisions of Article 5.3.
6.3 Back and forth difference test
In the test of 6.2, check the difference between the positive stroke and reverse stroke indications of the same test point after tapping. 6.4 Tap displacement test
In the test of 6.2, check the difference between the indications of the same test point before and after tapping. 6.5 Pointer deflection stability test
Use the load evenly and slowly from zero point to the upper limit of measurement, and then reduce the load evenly and slowly to zero point to observe the stability of the instrument pointer or dial deflection.
6.6 Overload test
Under the test conditions of 6.1.1, the instrument shall be subjected to overload test as specified in Table 2. After removing the load, it shall be tested according to 6.2 to 6.5 within 30 minutes.
6.7 Temperature influence test
Put the instrument in a constant temperature box, gradually increase (decrease) the temperature to the upper (lower) limit of the temperature range specified in 5.1.1 of this standard, and make the instrument bear a load of 2/3 of the upper limit of measurement. After the temperature stabilizes and remains for not less than 3 hours, perform temperature influence test on the indication of the instrument after tapping according to the method specified in 6.2.1.
6.8 Test against pulsation of the measured medium
Under the test conditions of 6.1.1, install the meter on an alternating load machine that can generate a sinusoidal waveform and a frequency of 60±5 times/min, and apply a load so that its median value is at a test point between 40% and 50% of the upper limit of measurement. The load change amplitude is 15% of the upper limit of measurement. After the alternating amplitude of the meter is stable, check the meter reduction ratio and pulsation error. 6.9 Alternating load test
Under the test conditions of 6.1.1, install the meter on an alternating load machine that can generate a sinusoidal waveform and a frequency of 60±5 times/min for testing. The alternating amplitude and number of times shall comply with the provisions of Table 3. After the test, the meter shall be inspected within 30 minutes according to 6.2 to 6.5. 6.10 Test of anti-working environment vibration performance
The instrument shall be tested according to the test procedure specified in GB4451 for instruments with working vibration conditions of V·H·4 or V·H·5, corresponding to the parameters of 2-B or 3-C specified in GB4451 respectively. Among them: a. The durability test adopts a fixed frequency test. During the test, the load shall be applied to the instrument to a test point between 50% and 60% of the upper limit of the measurement. During the vibration, observe whether the maximum value of the instrument pointer or dial deviating from this point meets the provisions of Article 5.11. b. The final vibration response check can be omitted. c. After the test, the instrument shall be restored for 30 minutes and then tested according to Articles 6.2-6.5. 6.11 Test of anti-transportation environment performance
The test shall be carried out according to the method specified in ZBY002. After the test, the instrument shall be tested according to Articles 6.2 to 6.5. 6.12 Case sealing test
Put the instrument case in water, add 0.07MPA air pressure from the filling hole or exhaust hole of the case, and keep it for 5 minutes, then observe whether the case leaks.
6.13 Appearance inspection
Visual inspection.
7 Inspection rules
71 Factory inspection
71.1 Inspection items
a. Basic error;
b, back and forth difference;
c. Tap displacement;
d. Pointer deflection stability;
e. Appearance.
7.1.2 Sampling and judgment rules
JB/T6804-93
The factory inspection department shall inspect each instrument according to the factory inspection items. When one item of an instrument fails to meet the standards, the instrument is judged as an unqualified product. Only instruments that meet all the specified factory inspection items can be judged as qualified products and can only leave the factory with a product certificate.
7.2 Type test
7.2.1 Inspection items
In the following cases, the instrument shall be subject to type inspection according to all technical requirements of this standard: a. Trial design of new products;
b. Regular inspection of batch-produced instruments once a year; c. When there are major changes in design, process, materials, etc.; d. When the instrument that has been stopped for more than one year is produced again. Note: The test in item b and d of item 6.11 may not be carried out. 7.2.2 Sampling and judgment rules
In the cases of item a and c of item 7.2.1, three instruments shall be randomly selected from the trial samples as the inspected products; in the cases of item b and d of item 7.2.1, four instruments shall be randomly selected from the same batch of products as the inspected products. Only when each product meets the requirements of the specified inspection items, the type inspection will pass. If one item of a product does not meet the requirements, a and c will fail the inspection, and b and d will be doubled for inspection. After the inspection, only when all the products meet the requirements of all inspection items, the type inspection will pass, otherwise the type inspection will not pass.
8 Marking, packaging and storage
8.1 Marking
Instruments should generally be marked with:
a. Manufacturer name or trademark;
b. Instrument name;
c. Unit of measurement;
d. Accuracy level:
e. Year and month of manufacture and instrument number or batch number; f. Normal working environment temperature;
g. Vibration resistance level.
Note: f and d can be marked in the instrument manual or other signs. 8.2 Packaging
The instrument packaging should comply with the provisions of ZBY003. The packaging protection type shall be determined by the manufacturer. 8.3 Storage
The instrument should be stored in a ventilated and dry room. The indoor air should be clean and non-corrosive to the instrument. 5
Overload
Anti-pulsation of the measured medium
Alternating load
Anti-vibration performance in the working environment
Anti-transportation environment performance
JB/T6804-93
Appendix A
Test sequence and interval time between items
(Supplement)
Indication inspection includes basic error, back and forth difference, tapping displacement and pointer deflection stability inspection
Before inspection, the instrument should be Place at reference temperature for no less than 4 hours and conduct indication test within 30 minutes after the test
Park for no less than 1 hour
Place at room temperature for no less than 2 hours
Place at reference temperature for no less than 4 hours
Conduct indication test within 30 minutes after the test
Place at reference temperature for no less than 2 hours
Instrument case sealing
Note: The instrument's anti-transportation environment performance and instrument case sealing performance tests can be conducted separately. Additional notes:
This standard was proposed and managed by Xi'an Industrial Automation Instrument Research Institute. This standard was drafted by Xi'an Industrial Automation Instrument Research Institute. The main drafters of this standard: Song Jianjun, Zhang Shaoping, Zhang Zhilan, Zou Hengwen, Zhu Liqiang. People's Republic of China
Mechanical Industry Standard
Vibration-resistant Pressure Gauge
JB/T6804-93
Instrumentation and Metering Comprehensive Technology Department of the Ministry of Machinery Industry, Beijing Machinery Enterprise Association, Printing Service Department, Printing
Instrumentation and Metering Comprehensive Technology Management of the Instrument Group of the Ministry of Machinery Industry*
First Edition in March 1995
Print Quantity: 150 Copies
July 1997
Cost: 5.00 YuanAfter the test, the instrument must be restored for 30 minutes and then inspected according to 6.2-6.5. 6.11 Test for resistance to transportation environment
Test according to the method specified in ZBY002. After the test, the instrument shall be inspected according to 6.2-6.5. 6.12 Case sealing test
Put the instrument case into water, add 0.07MPA air pressure from the filling hole or exhaust hole of the case, and keep it for 5 minutes, then observe whether the case has air leakage.
6.13 Appearance inspection
Visual inspection.
7 Inspection rules
71 Factory inspection
71.1 Inspection items
a. Basic error;
b, back and forth difference;
c. Tap displacement;
d. Pointer deflection stability;
e. Appearance.
7.1.2 Sampling and judgment rules
JB/T6804-93
The factory inspection department shall inspect each instrument according to the factory inspection items. When one item of an instrument fails, it shall be judged as an unqualified product. Only instruments that pass all the prescribed factory inspection items can be judged as qualified products and can be shipped with a product certificate.
7.2 Type test
7.2.1 Inspection items
In the following cases, the instrument shall be type inspected according to all the technical requirements of this standard: a. New product trial production;
b. Instruments produced in batches shall be inspected once a year; c. When there are major changes in design, process, materials, etc.; d. When an instrument that has been stopped for more than one year is produced again. Note: Tests in item b and d may not be conducted for item 6.11. 7.2.2 Sampling and judgment rules
In the two cases of a and c in 7.2.1, three instruments shall be randomly selected from the trial samples as the inspected products; in the two cases of b and d in 7.2.1, four instruments shall be randomly selected from the same batch of products as the inspected products. Only when each inspected product meets the requirements of the specified inspection items, the type inspection of this item is passed. If one item of a product does not meet the requirements, the inspection of a and c will be failed, and the samples of b and d will be doubled for re-inspection. After the inspection, the type inspection will be passed only when all the inspected products meet the requirements of all inspection items, otherwise the type inspection will be rejected.
8 Marking, packaging and storage
8.1 Marking
Instruments should generally be marked with:
a. Manufacturer name or trademark;
b. Instrument name;
c. Unit of measurement;
d. Accuracy level:
e. Year and month of manufacture and instrument number or batch number;
f. Normal working environment temperature;
g. Vibration resistance level.
Note: f and g can be marked in the instrument manual or other signs. 8.2 Packaging
Instrument packaging should comply with the provisions of ZBY003. The packaging protection type shall be determined by the manufacturer. 8.3 Storage
Instruments should be stored in a ventilated and dry room. The indoor air should be clean and non-corrosive to the instrument. 5
Overload
Anti-pulsation of measured medium
Alternating load
Anti-vibration performance in working environment
Anti-transportation environment performance
JB/T6804-93
Appendix A
Test sequence and interval time between items
(Supplement)
Indication inspection includes basic error, back and forth difference, tapping displacement and pointer deflection stability inspection
Before inspection, the instrument should be Place at reference temperature for no less than 4 hours and conduct indication test within 30 minutes after the test
Park for no less than 1 hour
Place at room temperature for no less than 2 hours
Place at reference temperature for no less than 4 hours
Conduct indication test within 30 minutes after the test
Place at reference temperature for no less than 2 hours
Instrument case sealing
Note: The instrument's anti-transportation environment performance and instrument case sealing performance tests can be conducted separately. Additional notes:
This standard was proposed and managed by Xi'an Industrial Automation Instrument Research Institute. This standard was drafted by Xi'an Industrial Automation Instrument Research Institute. The main drafters of this standard: Song Jianjun, Zhang Shaoping, Zhang Zhilan, Zou Hengwen, Zhu Liqiang. People's Republic of China
Mechanical Industry Standard
Vibration-resistant Pressure Gauge
JB/T6804-93
Instrumentation and Metering Comprehensive Technology Department of the Ministry of Machinery Industry, Beijing Machinery Enterprise Association, Printing Service Department, Printing
Instrumentation and Metering Comprehensive Technology Management of the Instrument Group of the Ministry of Machinery Industry*
First Edition in March 1995
Print Quantity: 150 Copies
July 1997
Cost: 5.00 YuanAfter the test, the instrument must be restored for 30 minutes and then inspected according to 6.2-6.5. 6.11 Test for resistance to transportation environment
Test according to the method specified in ZBY002. After the test, the instrument shall be inspected according to 6.2-6.5. 6.12 Case sealing test
Put the instrument case into water, add 0.07MPA air pressure from the filling hole or exhaust hole of the case, and keep it for 5 minutes, then observe whether the case has air leakage.
6.13 Appearance inspection
Visual inspection.
7 Inspection rules
71 Factory inspection
71.1 Inspection items
a. Basic error;
b, back and forth difference;
c. Tap displacement;
d. Pointer deflection stability;
e. Appearance.
7.1.2 Sampling and judgment rules
JB/T6804-93
The factory inspection department shall inspect each instrument according to the factory inspection items. When one item of an instrument fails, it shall be judged as an unqualified product. Only instruments that pass all the prescribed factory inspection items can be judged as qualified products and can be shipped with a product certificate.
7.2 Type test
7.2.1 Inspection items
In the following cases, the instrument shall be type inspected according to all the technical requirements of this standard: a. New product trial production;
b. Instruments produced in batches shall be inspected once a year; c. When there are major changes in design, process, materials, etc.; d. When an instrument that has been stopped for more than one year is produced again. Note: Tests in item b and d may not be conducted for item 6.11. 7.2.2 Sampling and judgment rules
In the two cases of a and c in 7.2.1, three instruments shall be randomly selected from the trial samples as the inspected products; in the two cases of b and d in 7.2.1, four instruments shall be randomly selected from the same batch of products as the inspected products. Only when each inspected product meets the requirements of the specified inspection items, the type inspection of this item is passed. If one item of a product does not meet the requirements, the inspection of a and c will be failed, and the samples of b and d will be doubled for re-inspection. After the inspection, the type inspection will be passed only when all the inspected products meet the requirements of all inspection items, otherwise the type inspection will be rejected.
8 Marking, packaging and storage
8.1 Marking
Instruments should generally be marked with:
a. Manufacturer name or trademark;
b. Instrument name;
c. Unit of measurement;
d. Accuracy level:
e. Year and month of manufacture and instrument number or batch number;
f. Normal working environment temperature;
g. Vibration resistance level.
Note: f and g can be marked in the instrument manual or other signs. 8.2 Packaging
Instrument packaging should comply with the provisions of ZBY003. The packaging protection type shall be determined by the manufacturer. 8.3 Storage
Instruments should be stored in a ventilated and dry room. The indoor air should be clean and non-corrosive to the instrument. 5
Overload
Anti-pulsation of measured medium
Alternating load
Anti-vibration performance in working environment
Anti-transportation environment performance
JB/T6804-93
Appendix A
Test sequence and interval time between items
(Supplement)
Indication inspection includes basic error, back and forth difference, tapping displacement and pointer deflection stability inspection
Before inspection, the instrument should be Place at reference temperature for no less than 4 hours and conduct indication test within 30 minutes after the test
Park for no less than 1 hour
Place at room temperature for no less than 2 hours
Place at reference temperature for no less than 4 hours
Conduct indication test within 30 minutes after the test
Place at reference temperature for no less than 2 hours
Instrument case sealing
Note: The instrument's anti-transportation environment performance and instrument case sealing performance tests can be conducted separately. Additional notes:
This standard was proposed and managed by Xi'an Industrial Automation Instrument Research Institute. This standard was drafted by Xi'an Industrial Automation Instrument Research Institute. The main drafters of this standard: Song Jianjun, Zhang Shaoping, Zhang Zhilan, Zou Hengwen, Zhu Liqiang. People's Republic of China
Mechanical Industry Standard
Vibration-resistant Pressure Gauge
JB/T6804-93
Instrumentation and Metering Comprehensive Technology Department of the Ministry of Machinery Industry, Beijing Machinery Enterprise Association, Printing Service Department, Printing
Instrumentation and Metering Comprehensive Technology Management of the Instrument Group of the Ministry of Machinery Industry*
First Edition in March 1995
Print Quantity: 150 Copies
July 1997
Cost: 5.00 Yuan3 Storage
The instrument should be stored in a ventilated and dry room. The indoor air should be clean and non-corrosive to the instrument. 5
Overload
Anti-measurement medium pulsation
Alternating load
Anti-working environment vibration performance
Anti-transportation environment performance
JB/T6804-93
Appendix A
Test sequence and interval time between items
(Supplement)
Indication inspection includes basic error, back and forth difference, tapping displacement and pointer deflection stability inspection
Before inspection, the instrument should be Place at reference temperature for no less than 4 hours and conduct indication test within 30 minutes after the test
Park for no less than 1 hour
Place at room temperature for no less than 2 hours
Place at reference temperature for no less than 4 hours
Conduct indication test within 30 minutes after the test
Place at reference temperature for no less than 2 hours
Instrument case sealing
Note: The instrument's anti-transportation environment performance and instrument case sealing performance tests can be conducted separately. Additional notes:
This standard was proposed and managed by Xi'an Industrial Automation Instrument Research Institute. This standard was drafted by Xi'an Industrial Automation Instrument Research Institute. The main drafters of this standard: Song Jianjun, Zhang Shaoping, Zhang Zhilan, Zou Hengwen, Zhu Liqiang. People's Republic of China
Mechanical Industry Standard
Vibration-resistant Pressure Gauge
JB/T6804-93
Instrumentation and Metering Comprehensive Technology Department of the Ministry of Machinery Industry, Beijing Machinery Enterprise Association, Printing Service Department, Printing
Instrumentation and Metering Comprehensive Technology Management of the Instrument Group of the Ministry of Machinery Industry*
First Edition in March 1995
Print Quantity: 150 Copies
July 1997
Cost: 5.00 Yuan3 Storage
The instrument should be stored in a ventilated and dry room. The indoor air should be clean and non-corrosive to the instrument. 5
Overload
Anti-measurement medium pulsation
Alternating load
Anti-working environment vibration performance
Anti-transportation environment performance
JB/T6804-93
Appendix A
Test sequence and interval time between items
(Supplement)
Indication inspection includes basic error, back and forth difference, tapping displacement and pointer deflection stability inspection
Before inspection, the instrument should be Place at reference temperature for no less than 4 hours and conduct indication test within 30 minutes after the test
Park for no less than 1 hour
Place at room temperature for no less than 2 hours
Place at reference temperature for no less than 4 hours
Conduct indication test within 30 minutes after the test
Place at reference temperature for no less than 2 hours
Instrument case sealing
Note: The instrument's anti-transportation environment performance and instrument case sealing performance tests can be conducted separately. Additional notes:
This standard was proposed and managed by Xi'an Industrial Automation Instrument Research Institute. This standard was drafted by Xi'an Industrial Automation Instrument Research Institute. The main drafters of this standard: Song Jianjun, Zhang Shaoping, Zhang Zhilan, Zou Hengwen, Zhu Liqiang. People's Republic of China
Mechanical Industry Standard
Vibration-resistant Pressure Gauge
JB/T6804-93
Instrumentation and Metering Comprehensive Technology Department of the Ministry of Machinery Industry, Beijing Machinery Enterprise Association, Printing Service Department, Printing
Instrumentation and Metering Comprehensive Technology Management of the Instrument Group of the Ministry of Machinery Industry*
First Edition in March 1995
Print Quantity: 150 Copies
July 1997
Cost: 5.00 Yuan
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