JB/T 9094-1999 Technical requirements for emergency shut-off valves for liquefied petroleum gas equipment
Some standard content:
JB/T 9094--1999
This standard is a revision of Z13J16008
8-1990 "Technical conditions for emergency shut-off valves for liquefied petroleum gas equipment". The main technical differences between this standard and ZBJ16008-1990 are as follows: 1. The structure, technical elements and expression rules of the standard are modified according to GB/T1.3-1997; 2. The numerator p (d-2c) in the brackets of the calculation formula for the minimum wall thickness of the valve body in the technical requirements of ZBJ160081990 is changed to p (d. + 2c); 3. The material of the pilot valve 1Cr18Ni9 is changed to stainless steel or carbon steel with nickel-phosphorus plating on the surface; 4. The over-temperature closing performance is changed from the valve temperature reaching 70C ± 5 (to 75℃ ± 5 (; 5. The test pressure and test method of the shell test are changed from GB4981 to GB/T13927; 6. For the melting test of fusible components, the melting temperature of 70℃±5℃ is changed to 75℃±5℃. This standard will replace ZBJ16008--1990 from the date of implementation.
This standard is proposed and managed by the National Valve Standardization Technical Committee. The drafting unit of this standard: Beijing Valve Research Institute. The main drafter of this standard: Lu Peiwen.
1 Scope
Mechanical Industry Standard of the People's Republic of China
Emergency Shut-off Valve for Liquefied Petroleum Gas Equipment
Technical Conditions
Emergency Shutoff valve for LPG equipment--Technical specification
JB/T 9094 . 1999
Replaces ZB J16 008--90
This standard specifies the general technical requirements, test methods, inspection rules, marking and supply requirements for emergency shutoff valves and over-flow valves. This standard applies to emergency shutoff valves and over-flow valves for liquefied petroleum gas storage and transportation equipment, and also to emergency shutoff valves and over-flow valves used on liquid ammonia storage and transportation equipment.
2 Cited 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 the parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T699--1988 Technical conditions for high-quality carbon structural steel GB/T 1220-1992
2 Stainless steel bars
GB/T 4240--1993
Stainless steel wire
GB/T 9113. 1~~9113.26--1988
GB/T 12220--1989
GB/T 12228—1989
GB/T 12229--1989
GB/T1 3927—1992
JB/T 6697---1993
JB/T 7748 -- 1995
JB/T 7927-1999
JIB/T 7928--1999
3 Terms
3.1 Emergency shut-off valve
Integral steel pipe flange
General valve
General valve
Technical conditions for carbon steel forgings
Technical conditions for carbon steel castings
General valve
General valve pressure test
Basic technical conditions for tractor electrical equipment
Valve cleanliness and determination method
Appearance quality requirements for valve steel castings
General valve supply requirements
A valve installed on a tank truck (tank car), storage tank or pipeline, which is closed quickly by manual or automatic operation in the event of an accident. 3.2 Overflow valve
A valve that automatically closes when the flow rate of the medium in the pipeline exceeds the pressure difference caused by the rated value 3.3 Rated flow
The maximum flow allowed before the overflow valve automatically closes. 3.4 Closing time
When the emergency shut-off valve is closed by hydraulic or pneumatic pressure, the time from the operator starting to act to the closure of the liquid flow is expressed in $. Approved by the State Bureau of Machinery Industry on July 12, 1999 and implemented on January 1, 2000
3.5 Built-in
Emergency shut-off valve with the main part inside the tank. 3.6 Externalbzxz.net
JB/T9094-1999
Emergency shut-off valve installed on the outer flange of the tank or on the pipeline. 4 Classification
4.1 Structural form
4.1.1 The structural form of the emergency shut-off valve for pipelines is shown in Figure 1. 4.1.2 The structural form of the emergency shut-off valve for automobile tank trucks is shown in Figures 2 and 3. 4.1.3 The structural form of the emergency shut-off valve for train tank trucks is shown in Figure 4. 4.7.4 The structural form of the emergency shut-off valve for spherical tanks is shown in Figures 5 and 6. Cylinder head
Sealing ring
Zhanzhai head
Oil cyanide
JB/T 9094---1999
Teng Mo end
JB/T 9094--1999
Cylinder body
Pilot valve
Upper valve cover
Upper spring
Lower spring
Lower wide cover
4.2 The model compilation method of the emergency cut-off valve is as follows: Model compilation method
Simple emergency cut-off valve
Combination of emergency cut-off valve and over-current limiting valve
Combination of emergency cut-off valve, over-current limiting valve and stop valve Combination of emergency cut-off valve, over-current limiting valve and ball valve JB/T9094--1999
DN 100--DN 300
Nominal pressure
Valve sealing surface material
Valve body type
Installation method
Connection method
Transmission method
-Type
5 Technical requirements
5.1 Parameters
Transmission method
Connection type
Quick connector
Installation type
Valve body type
Valve sealing surface material
Nylon plastic
JB/T90941999
5.1.1 The maximum working pressure of the valve is the design pressure of the tank body, as specified in Table 1. Table 1
Type of filling medium
Butadiene
Mixed gas with butane and propane as main components, with the mixing ratio of butane above 70% (molar)
5.1.2 The operating temperature of the valve is -40～+50℃. 5.2 Valve body
5.2.1 The minimum wall thickness of the valve body is calculated as follows: Where: t-
Nominal pressure PN
t = 1. 5[2[8,]-
p(d, + 2c)
The minimum calculated value of the valve body wall thickness, mm;
Design pressure, take the nominal pressure PN, MPa; [a]—Permissible tensile stress of the material at room temperature, N/mm\; 574
Maximum working pressure
Valve inlet diameter, mm;
JB/T 9094—1999
An additional margin, mm, determined by the designer, can be 1~3mm. 5.2-2 Flange connection dimensions shall comply with the provisions of GB/T9113.1~~9113.26. 5.3 Materials
The materials used for emergency shut-off valves shall be resistant to corrosion by liquefied petroleum gas and low temperatures of -40°C; copper materials are not allowed for emergency shut-off valves for liquid ammonia.
5.3.1 Carbon steel castings shall comply with the provisions of GB/T12229. 5.3.2 Carbon steel forgings shall comply with the provisions of GB/T12228. 5.3.3 The pilot valve shall be made of stainless steel and comply with the provisions of GB/T1220, and its surface shall be heat treated; it may also be made of carbon steel and comply with the provisions of GB/T699, and its surface shall be plated with nickel-phosphorus; its surface hardness shall not be less than HV874. 5.3.4 The spiral compression spring in contact with the medium shall be made of 1Cr18.Ni9 and comply with the provisions of GB/T4240. 5.3.5
The fusible alloy used for the fusible plug shall ensure melting at 75°C ± 5°C; its chemical composition shall comply with the provisions of Table 2. Table 2
5.3.6 O-rings should be made of materials resistant to liquefied petroleum gas or liquid ammonia. 5.4 Performance requirements
5.4.1 Sealing performance
The test pressure is 0.1MPa and the maximum working pressure respectively, and the test medium is air (or nitrogen). The leakage shall not exceed 2×DNml./min.
5.4.2 Over-current cut-off valve performance
When the flow rate of the medium at the valve outlet reaches the rated flow rate, the valve shall be able to close automatically, and the rated flow rate error is allowed to be within 10% of the soil. 5.4.3 Closing time shall be in accordance with the provisions of Table 3.
Nominal diameter DN,mm
65~100
5.4.4 Vibration resistance
Closing time, 5
The vibration resistance of the emergency shut-off valve for tank trucks shall comply with the provisions of "Products in other parts" in JB/T6697-~1993. 5.4.5 Over-temperature closing performance
The emergency shut-off valve shall ensure automatic closing when the temperature of the valve itself reaches 75℃±5℃. 5.4.6 Natural closing performance
For valves opened and closed by oil pressure or air pressure, the valve should be able to be placed continuously for 48 hours when fully open without natural closing. 5.4.7 Repeated operation performance
It should be able to be opened and closed 2000 times under no-load conditions to meet the factory performance requirements. 6 Test methods
6.1 Shell test
6.1.1The test pressure and test method shall comply with the provisions of GB/T13927. 6.1.2The test duration shall comply with the provisions of Table 4. 675
Nominal diameter DN, mm
Test duration, min
6.2 Leakage test
6.2.1 The test pressure is the maximum working pressure. 6.2.2 The test medium is air or nitrogen.
JB/T9094-1999
65~200
6.2.3 During the test, the valve is in the open state, the outlet end is closed, and the pressure is introduced from the inlet end. The connection and sealing parts of the screw plug, cross shaft, valve body and valve cover shall not leak.
6.2.4 The test duration shall be in accordance with the provisions of Table 5. Table 5
Nominal diameter DN, mm
Test duration, min
Airtight test
65~200
The test pressure is 0.1MPa and the maximum working pressure respectively. 6.3.2
The test medium is air or nitrogen
250~~450
6.3.3 During the test, the valve is in the closed state, and the pressure is introduced from the inlet. The total leakage of the two sealing surfaces of the pilot valve and the overflow valve shall not exceed the provisions of 4.4.1.
6.3.4 The test duration shall be in accordance with the provisions of Table 5. 6.4 Action test
Use oil or air to apply the same test pressure as the maximum working pressure in the flow direction of the medium. When the emergency shut-off valve starts to operate, it must be guaranteed to be closed within the time specified in Table 3.
6.5 Overflow performance test
6.5.1 The test medium is water, oil or air. 6.5.2 During the test, the valve is in the open state, and the medium is introduced from the inlet. When the rated flow is reached, the overflow valve shall be automatically closed. 6.5.3 The rated flow error is allowed to be within ±10%. 6.5.4 The overflow test system is shown in Figure 7. 1
1--Relief valve: 2-Centrifugal pump: 3-Pressure regulating tank; 4, 6, 8---Valve: 5-Wheel flowmeter; 7-Test cut-off valve; 9, 10, 11-Pressure gauge Fig. 7
6.6 Natural closing test
Emergency cut-off valve opened and closed by oil pressure or air pressure, open the valve and stop adding oil to the hydraulic system. The valve should meet the requirements of 4.4.6.
6.7 Vibration test
6.7.1 The valve is in the closed state, and the vibration test is carried out according to the provisions of "other parts of the product" in JB/T6697-1993.576
JB/T9094-1999
6.7.2 After the vibration test, the valve is subjected to external inspection. The parts should be free of damage, the fasteners should not be loose, and the "press and release" inspection items should be qualified. 6.8 Repeated operation test
The valve is repeatedly operated under no-load state. The "press and release" inspection items should be qualified every 500, 1000, 1300, 1600, 1800, 2000 times of opening and closing.
6.9 Fusible element melting test
The fusible element of the emergency shut-off valve should be melted when the temperature reaches 75℃±5℃ according to the test device shown in Figure 8. During the test, the liquid in the device should be frequently stirred, and the average temperature should rise by 1°C every 2 to 3 minutes, gradually approaching the specified temperature. 5
1 Heat source; 2—Steel pipe; 3—Water or oil; 4—Test object; 5—Internal pressure regulating valve; 6—Thermometer; 7—Stirring rod Figure 8
7 Inspection rules
7.1 Delivery inspection
7.1.1 Each valve must undergo factory inspection, and can only be shipped after all inspection items are qualified. 7.1.2 Factory inspection items, technical requirements and inspection methods shall be in accordance with the provisions of Table 6. Table 6
Inspection items
Shell test
Leakage test
Airtightness test
Action test
Overcurrent performance test
Natural closing test
Vibration test
Repeated operation test
Fusible element melting test
Minimum wall thickness of valve body
Inspection of cleanliness of inner cavity
Appearance inspection
7.2 Type inspection
Inspection category
Factory inspection
Type inspection
Technical requirements
Inspection and test
GB/T 13927
JB/T6697
Conventional measuring tools
JB/T7748
JB/T7927
JB/T9094—1999
7.2.1 Type inspection shall be carried out in any of the following cases: a) trial production appraisal when new products or old products are transferred to the factory for production; b) during formal production, this inspection shall be carried out periodically after a certain amount of production has been accumulated; c) during formal production, when there are major changes in structure, materials, and processes that may affect product performance; d) when the product is resumed after a long period of suspension; e) when there is a significant difference between the factory inspection result and the last type inspection result; f) when the quality supervision agency proposes a type inspection requirement. 7.2.2 Type inspection shall be carried out by sampling inspection. The inspection samples can be randomly selected from the qualified inventory products inspected by the quality inspection department of the production plant, or randomly selected from the products that have been supplied to users but not used and are in the factory state. The minimum batch and sampling quantity of each specification shall be in accordance with the provisions of Table 7. When sampling by users, the minimum batch for sampling is not limited by Table 7, and the sampling quantity shall still be in accordance with the provisions of Table 7. Table 7
Nominal diameter DN, mm
Minimum number of units for sampling
7.2.3Type inspection items, technical requirements, tests and inspection methods shall be in accordance with the provisions of Table 6. Number of sampling units
7.2.4The shell test, leakage test and airtightness test results of each valve to be inspected in the type inspection must comply with the provisions of the corresponding technical requirements in Table 6; if one of the indicators of a valve in the other inspection items does not comply with the provisions of the technical requirements in Table 6, it is allowed to re-select the specified number of sampling units from the valves for sampling. When re-inspected, the results of all inspection items must comply with the provisions of the technical requirements in Table 6, otherwise it will be judged as unqualified.
8 Marking
Marking shall comply with the provisions of G13/T12220.
9 Supply requirements
Supply requirements shall comply with the provisions of JB/T7928.3 During the test, the valve is in the closed state, and the pressure is introduced from the inlet. The total leakage of the two sealing surfaces of the pilot valve and the overflow valve shall not exceed the provisions of 4.4.1.
6.3.4 The test duration shall be in accordance with the provisions of Table 5. 6.4 Action test
Use oil or air to apply the same test pressure as the maximum working pressure in the flow direction of the medium. When the emergency shut-off valve starts to operate, it must be guaranteed to be closed within the time specified in Table 3.
6.5 Overflow performance test
6.5.1 The test medium is water, oil or air. 6.5.2 During the test, the valve is in the open state, and the medium is introduced from the inlet end. When the rated flow is reached, the overflow valve shall be automatically closed. 6.5.3 The rated flow error is allowed to be within ±10%. 6.5.4 The overflow test system is shown in Figure 7. 1
1--Relief valve: 2-Centrifugal pump: 3-Pressure regulating tank; 4, 6, 8---Valve: 5-Wheel flowmeter; 7-Test cut-off valve; 9, 10, 11-Pressure gauge Fig. 7
6.6 Natural closing test
Emergency cut-off valve opened and closed by oil pressure or air pressure, open the valve and stop adding oil to the hydraulic system. The valve should meet the requirements of 4.4.6.
6.7 Vibration test
6.7.1 The valve is in the closed state, and the vibration test is carried out according to the provisions of "other parts of the product" in JB/T6697-1993.576
JB/T9094-1999
6.7.2 After the vibration test, the valve is subjected to external inspection. The parts should be free of damage, the fasteners should not be loose, and the "press and release" inspection items should be qualified. 6.8 Repeated operation test
The valve is subjected to repeated operation test under no-load state. The "press and release" inspection items should be qualified every 500, 1000, 1300, 1600, 1800, 2000 times of opening and closing.
6.9 Fusible element melting test
The fusible element of the emergency shut-off valve should be melted when the temperature reaches 75℃±5℃ according to the test device shown in Figure 8. During the test, the liquid in the device should be frequently stirred, and the average temperature should rise by 1°C every 2 to 3 minutes, gradually approaching the specified temperature. 5
1 Heat source; 2—Steel pipe; 3—Water or oil; 4—Test object; 5—Internal pressure regulating valve; 6—Thermometer; 7—Stirring rod Figure 8
7 Inspection rules
7.1 Delivery inspection
7.1.1 Each valve must undergo factory inspection, and can only be shipped after all inspection items are qualified. 7.1.2 Factory inspection items, technical requirements and inspection methods shall be in accordance with the provisions of Table 6. Table 6
Inspection items
Shell test
Leakage test
Airtightness test
Action test
Overcurrent performance test
Natural closing test
Vibration test
Repeated operation test
Fusible element melting test
Minimum wall thickness of valve body
Inspection of cleanliness of inner cavity
Appearance inspection
7.2 Type inspection
Inspection category
Factory inspection
Type inspection
Technical requirements
Inspection and test
GB/T 13927
JB/T6697
Conventional measuring tools
JB/T7748
JB/T7927
JB/T9094—1999
7.2.1 Type inspection shall be conducted in any of the following cases: a) trial production appraisal when new products or old products are transferred to the factory for production; b) during formal production, this inspection shall be conducted periodically after a certain amount of production has been accumulated; c) during formal production, when there are major changes in structure, materials, and processes that may affect product performance; d) when the product is resumed after a long period of suspension; e) when there is a significant difference between the factory inspection result and the last type inspection result; f) when the quality supervision agency proposes a type inspection requirement. 7.2.2 Type inspection shall be conducted by sampling inspection. The inspection samples can be randomly selected from the qualified inventory products inspected by the quality inspection department of the production plant, or randomly selected from the products that have been supplied to users but not used and are in the factory state. The minimum batch and sampling quantity for each specification shall be in accordance with the provisions of Table 7. When sampling by users, the minimum batch for sampling is not limited by Table 7, and the sampling quantity shall still be in accordance with the provisions of Table 7. Table 7
Nominal diameter DN, mm
Minimum number of units for sampling
7.2.3Type inspection items, technical requirements, tests and inspection methods shall be in accordance with the provisions of Table 6. Number of sampling units
7.2.4The shell test, leakage test and airtightness test results of each valve to be inspected in the type inspection must comply with the provisions of the corresponding technical requirements in Table 6; if one of the indicators of a valve in the other inspection items does not comply with the provisions of the technical requirements in Table 6, it is allowed to re-select the specified number of sampling units from the valves for sampling. When re-inspected, the results of all inspection items must comply with the provisions of the technical requirements in Table 6, otherwise it will be judged as unqualified.
8 Marking
Marking shall comply with the provisions of G13/T12220.
9 Supply requirements
Supply requirements shall comply with the provisions of JB/T7928.3 During the test, the valve is in the closed state, and the pressure is introduced from the inlet. The total leakage of the two sealing surfaces of the pilot valve and the overflow valve shall not exceed the provisions of 4.4.1.
6.3.4 The test duration shall be in accordance with the provisions of Table 5. 6.4 Action test
Use oil or air to apply the same test pressure as the maximum working pressure in the flow direction of the medium. When the emergency shut-off valve starts to operate, it must be guaranteed to be closed within the time specified in Table 3.
6.5 Overflow performance test
6.5.1 The test medium is water, oil or air. 6.5.2 During the test, the valve is in the open state, and the medium is introduced from the inlet end. When the rated flow is reached, the overflow valve shall be automatically closed. 6.5.3 The rated flow error is allowed to be within ±10%. 6.5.4 The overflow test system is shown in Figure 7. 1
1--Relief valve: 2-Centrifugal pump: 3-Pressure regulating tank; 4, 6, 8---Valve: 5-Wheel flowmeter; 7-Test cut-off valve; 9, 10, 11-Pressure gauge Fig. 7
6.6 Natural closing test
Emergency cut-off valve opened and closed by oil pressure or air pressure, open the valve and stop adding oil to the hydraulic system. The valve should meet the requirements of 4.4.6.
6.7 Vibration test
6.7.1 The valve is in the closed state, and the vibration test is carried out according to the provisions of "other parts of the product" in JB/T6697-1993.576
JB/T9094-1999
6.7.2 After the vibration test, the valve is subjected to external inspection. The parts should be free of damage, the fasteners should not be loose, and the "press and release" inspection items should be qualified. 6.8 Repeated operation test
The valve is repeatedly operated under no-load state. The "press and release" inspection items should be qualified every 500, 1000, 1300, 1600, 1800, 2000 times of opening and closing.
6.9 Fusible element melting test
The fusible element of the emergency shut-off valve should be melted when the temperature reaches 75℃±5℃ according to the test device shown in Figure 8. During the test, the liquid in the device should be frequently stirred, and the average temperature should rise by 1°C every 2 to 3 minutes, gradually approaching the specified temperature. 5
1 Heat source; 2—Steel pipe; 3—Water or oil; 4—Test object; 5—Internal pressure regulating valve; 6—Thermometer; 7—Stirring rod Figure 8
7 Inspection rules
7.1 Delivery inspection
7.1.1 Each valve must undergo factory inspection, and can only be shipped after all inspection items are qualified. 7.1.2 Factory inspection items, technical requirements and inspection methods shall be in accordance with the provisions of Table 6. Table 6
Inspection items
Shell test
Leakage test
Airtightness test
Action test
Overcurrent performance test
Natural closing test
Vibration test
Repeated operation test
Fusible element melting test
Minimum wall thickness of valve body
Inspection of cleanliness of inner cavity
Appearance inspection
7.2 Type inspection
Inspection category
Factory inspection
Type inspection
Technical requirements
Inspection and test
GB/T 13927
JB/T6697
Conventional measuring tools
JB/T7748
JB/T7927
JB/T9094—1999
7.2.1 Type inspection shall be conducted in any of the following cases: a) Trial production and appraisal of new products or old products when they are transferred to the factory for production; b) During formal production, this inspection shall be conducted periodically after a certain amount of production has been accumulated; c) During formal production, if there are major changes in structure, materials, and processes, which may affect product performance; d) When the product is resumed after a long period of suspension; e) When the factory inspection results are significantly different from the last type inspection; f) When the quality supervision agency proposes a type inspection requirement. 7.2.2 Type inspection shall be conducted by sampling inspection. The inspection samples can be randomly selected from the qualified inventory products inspected by the quality inspection department of the production plant, or randomly selected from the products that have been supplied to users but not used and are in the factory state. The minimum batch and sampling quantity of each specification shall be in accordance with the provisions of Table 7. When sampling by users, the minimum batch for sampling is not limited by Table 7, and the sampling quantity shall still be in accordance with the provisions of Table 7. Table 7
Nominal diameter DN, mm
Minimum number of units for sampling
7.2.3Type inspection items, technical requirements, tests and inspection methods shall be in accordance with the provisions of Table 6. Number of sampling units
7.2.4The shell test, leakage test and airtightness test results of each valve inspected in the type inspection must comply with the provisions of the corresponding technical requirements in Table 6; if one of the indicators of a valve in the other inspection items does not comply with the provisions of the technical requirements in Table 6, it is allowed to re-select the specified number of sampling units from the valves for sampling. When re-inspected, the results of all inspection items must comply with the provisions of the technical requirements in Table 6, otherwise it will be judged as unqualified.
8 Marking
Marking shall comply with the provisions of G13/T12220.
9 Supply requirements
Supply requirements shall comply with the provisions of JB/T7928.1 Type inspection shall be conducted in any of the following cases: a) trial production identification of new products or old products when they are transferred to the factory for production; b) during formal production, this inspection shall be conducted periodically after a certain amount of production has been accumulated; c) during formal production, when there are major changes in structure, materials, and processes that may affect product performance; d) when the product is resumed after a long period of suspension; e) when the factory inspection results are significantly different from the last type inspection; f) when the quality supervision agency makes a type inspection request. 7.2.2 Type inspection shall be conducted by sampling. Inspection samples may be randomly selected from the inventory products that have passed the inspection of the quality inspection department of the production plant, or randomly selected from the products that have been supplied to users but have not been used and remain in the factory state. The minimum batch and sampling quantity for each specification shall be in accordance with the provisions of Table 7. When sampling is conducted by the user, the minimum batch for sampling is not subject to the restrictions of Table 7, and the sampling quantity shall still be in accordance with the provisions of Table 7. Table 7
Nominal diameter DN, mm
Minimum number of units for sampling
7.2.3Type inspection items, technical requirements, tests and inspection methods shall be in accordance with the provisions of Table 6. Number of sampling units
7.2.4The shell test, leakage test and airtightness test results of each valve under inspection during type inspection must comply with the corresponding technical requirements in Table 6; if one of the indicators of a valve in the remaining inspection items does not comply with the technical requirements in Table 6, it is allowed to re-sample the specified number of valves from the sampling. During the re-inspection, the results of all inspection items must comply with the technical requirements in Table 6, otherwise it will be judged as unqualified.
8Marking
Marking shall comply with the provisions of G13/T12220.
9Supply requirements
Supply requirements shall comply with the provisions of JB/T7928.1 Type inspection shall be conducted in any of the following cases: a) trial production identification of new products or old products when they are transferred to the factory for production; b) during formal production, this inspection shall be conducted periodically after a certain amount of production has been accumulated; c) during formal production, if there are major changes in structure, materials, and processes, which may affect product performance; d) when the product is resumed after a long period of suspension; e) when the factory inspection results are significantly different from the last type inspection; f) when the quality supervision agency makes a type inspection request. 7.2.2 Type inspection shall be conducted by sampling. Inspection samples may be randomly selected from the inventory products that have passed the inspection of the quality inspection department of the production plant, or randomly selected from the products that have been supplied to users but have not been used and remain in the factory state. The minimum batch and sampling quantity for each specification shall be in accordance with the provisions of Table 7. When sampling is conducted by the user, the minimum batch for sampling is not subject to the restrictions of Table 7, and the sampling quantity shall still be in accordance with the provisions of Table 7. Table 7
Nominal diameter DN, mm
Minimum number of units for sampling
7.2.3Type inspection items, technical requirements, tests and inspection methods shall be in accordance with the provisions of Table 6. Number of sampling units
7.2.4The shell test, leakage test and airtightness test results of each valve under inspection during type inspection must comply with the corresponding technical requirements in Table 6; if one of the indicators of a valve in the remaining inspection items does not comply with the technical requirements in Table 6, it is allowed to re-sample the specified number of valves from the valves for sampling. During the re-inspection, the results of all inspection items must comply with the technical requirements in Table 6, otherwise they will be judged as unqualified.
8Marking
Marking shall comply with the provisions of G13/T12220.
9Supply requirements
Supply requirements shall comply with the provisions of JB/T7928.
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