Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T7252--94
Valve-type orifice plate throttling device
Published on July 18, 1994
Ministry of Machinery Industry of the People's Republic of China
Implemented on July 1, 1995
Mechanical Industry Standard of the People's Republic of China
Valve-type orifice plate throttling device
1 Subject content and scope of application
JB/T7252-94
This standard specifies the terminology, type and basic parameters, technical requirements, test methods, inspection rules and marking, packaging, transportation and storage of valve-type orifice plate throttling devices.
This standard is applicable to valve-type orifice plate throttling devices (including standard orifice plates, valve-type main bodies with pressure-taking holes and front and rear measuring pipes) that use standard orifice plates as throttling parts and flange pressure taking.
Reference standards
GB1184
GB1801~1802
GB/T2624
GB9113.9~9113.13
Shape and position tolerancesTolerances and fits without tolerances
Flow measurement Orifice plates, nozzles and venturis for throttling devicesMeasuring the flow of fluids filling circular pipesIntegral steel pipe flanges
GB9115.17~9115.21Butt-welded steel pipe flangesGB12229||tt| |JB4730
JJG267
3 Terminology
3.1 Advanced orifice plate throttling device
Technical conditions for carbon steel castings of general valves
Non-destructive testing of pressure vessels
Verification procedures for flow measuring disc throttling devices
Flow measuring throttling devices with orifice plate lifting mechanism, which do not need to stop the medium transportation when replacing the orifice plate. 3.2 Ordinary valve type orifice plate throttling device
Flow measuring throttling device with orifice plate lifting mechanism, which do not need to remove the pipeline flange when replacing the orifice plate. 3.3 Simple wide orifice plate throttling device
Flow measuring throttling device without orifice plate lifting mechanism, which does not need to remove the pipeline flange when replacing the orifice plate: There are two connection types: flange connection and butt connection.
4 Types and basic parameters
4.1 Product model compilation method
The product model consists of the first letters of the Chinese pinyin and Arabic numerals, and is arranged as follows: Approved by the Ministry of Machinery Industry on July 18, 1994
Implemented on July 1, 1995
Model example:
JB/T7252-94
Nominal pressure (MPa×10)
Flange connection type (butt connection type is not marked)
Orifice plate is a throttling element
Product structure type: G-advanced type; P-ordinary type; J-simple type anti-H:S corrosion (not anti-HS corrosion, not marked) The nominal pressure is 4.0MPa. Anti-H, S corrosion, flange-connected advanced wide orifice throttling device. Its model is: KGKF-40. The model of the common wide orifice plate throttling device with a nominal pressure of 4.0MPa and flange connection is PKF-40. The model of the simple valve type orifice plate throttling device with a nominal pressure of 4.0MPa and flange connection is JKF-40. The nominal pressure is 4.0MPa, and the simple wide orifice throttling device with butt connection is model: JK-40. 4.2 Structural type
The typical structural type of the orifice throttling device (hereinafter referred to as the device) is shown in Figures 1 to 4. 12
Figure 1 Structural diagram of advanced valve-type orifice throttling device 1-orifice cover; 2-vent plug, 3-balance plug; 4-orifice body; 5-downstream measuring tube, 6-sliding plate, 7-oiling nozzle; 8-orifice guide plate: 9-orifice plate, 10-upstream measuring tube, 11-gear shaft: 12-pointer: 13-indicator plate: 14-reporting handle, 15-drain plug 2
JB/T 725294
Figure 2 Structural diagram of common valve type orifice throttling device 1- female cover: 2- valve body: 3- downstream measuring tube, 4- orifice guide plate: 5- orifice plate, 6- upstream measuring cover tube, 7- gear shaft, 8- crank handle: 9- sewage plug Figure 3 Structural diagram of simple reading type orifice throttling device- flange connection type 1- top plate; 2- pressure plate, 3- valve body, 4- downstream measuring tube, 5- orifice guide plate, 6- orifice plate, 7- upstream measuring tube; 8- sewage increase head 4.3
Basic parameters
JB/T725294||tt ||Figure 4 Simple valve type orifice throttling device - butt connection type structure diagram 1-neck plate; 2-pressure plate, 3-valve body: 4-downstream measuring tube: 5-orifice plate; 6-orifice plate, 7-upstream measuring tube: 8-drain plug buy fluid conditions: meet the requirements of Articles 5.2 and 5.3 of GB/T2624; nominal pressure p: 1.6~10MPa;
nominal diameter Dz: 50~600mm;
applicable temperature: -29~121℃;
applicable medium, natural gas, coal gas, water, light lubricant, light hydrocarbon, etc. 5 Technical requirements
The device shall comply with the provisions of this standard and be manufactured according to the drawings and technical documents approved by the prescribed procedures. 5.1
5.2 Shell performance
The shell (including the cover, body and upstream and downstream measuring pipes) must be subjected to a liquid pressure test at 1.5 times the nominal pressure. Within the duration specified in Table 1, there shall be no leakage or structural damage in any part. Table 1
Nominal diameter D
50~100
150~250
300~450
Shell performance test
Minimum test duration min
Sealing performance test
5.3 Sealing performance
JB/T725294
5.3.1 The sliding valve sealing pair shall be subjected to a liquid sealing test at 1.1 times the nominal pressure or a gas sealing test at a pressure of 0.6MPa. Within the duration specified in Table 1, when using a liquid test, there shall be no obvious visible dripping or moisture at the sealing part; when using a gas test, there shall be no air bubble leakage.
5.3.2 The orifice plate sealing pair shall be subjected to a gas sealing test at a pressure of 0.6MPa. Within the duration specified in Table 1, there shall be no air bubble leakage at the sealing part.
5.3.3 The device shall be tested for liquid tightness at 1.1 times the nominal pressure or for gas tightness at 0.6MPa. Within the duration specified in Table 1, there shall be no obvious dripping or moisture on the seal when testing with liquid; and no bubbles shall be leaked when testing with gas.
5.4 Body
Structural length L of wide body; advanced and ordinary types shall comply with the provisions of Table 2. Simple flange connection type shall comply with the provisions of Table 3. 5.4:1
Butt connection type shall comply with the provisions of Table 4. Structural length tolerance; when the nominal diameter D% is less than or equal to 250mm, the limit deviation is ±2mm; when the nominal diameter D is 250~500mm, the limit deviation is ±3mm. When the nominal diameter D is greater than 500mm, the limit deviation is ±4mm.
Nominal pressure
Nominal pressure P%
Structural length category
Long series
Long series
Short series
Long series
Short series
Long series
Short series
Structural length category
Long series
Short series
Long series
Short series
Long series
Short series
Long series
Short series
Nominal medical force
Nominal pressure
Structural length category
Long series
Short series
JB/T7252-94
Continued Table 3
Flange connection dimensions shall comply with the provisions of GB9113.9~9113.13. 5.4.2
The pressure tapping hole shall comply with the requirements of Article 7.2.1 of GB/T2624. 5.4.3
The limit deviation of the valve body diameter shall not be greater than Grade H11 in GB1801 and GB1802. The roundness tolerance of the diameter cylindrical surface shall not be lower than Grade 12 in GB5.4.4
1184. The coaxiality tolerance of the upstream and downstream diameters shall not be lower than Grade 12 in GB1184, and the roughness of the diameter cylindrical surface D%50~100mm shall not be lower than 6.3μm; D%150~600mm shall not be lower than 12.5μm. The coaxiality tolerance of the diameter axis and the inner cylindrical surface of the flange stop at both ends of the valve body shall not be lower than Grade 12 in GB1184. 5.5 Orifice
The design and manufacture of the orifice plate shall comply with the requirements of Article 7.1 of GB/T2624. 5.6 Measuring tube
The diameter of the measuring tube shall be equal to the diameter of the valve body. The length of the measuring tube, the upstream measuring tube length L, should not be less than 10D, and the downstream measuring tube length L should not be less than 5D. 5.6.3 The connection dimensions of the welding flanges at both ends of the upstream and downstream measuring pipes shall comply with the provisions of GB9115.17~9115.21. The flange welds at both ends of the upstream and downstream measuring pipes shall be subjected to ultrasonic and X-ray flaw detection in accordance with the provisions of JB4730. 5.6.4
5.6.5 The pipeline conditions of the measuring pipe shall comply with the requirements of Articles 6.1 and 6.5.1 of GB/T2624. 5.7 Assembly requirements
5.7.1 The installation of the orifice plate shall comply with the requirements of Article 6.5.2 of GB/T2624. 5.7.2 After the device is assembled, the parts of the diameter (including the orifice plate guide and seals) shall not protrude from the inner wall of the diameter, and there shall be no sudden changes at the connection between the wide body diameter and the diameter of the measuring pipe.
5.7.3 The distance from the end face of the orifice plate to the axis of the pressure tapping hole shall be 25.4±0.8mm. 5.7.4 For devices with orifice plate lifting mechanism, the orifice plate lifting and lowering shall be flexible after assembly. There shall be no jamming when opening and closing the slide valve. 5.8 Materials
5.8.1 The materials of the main parts of the device can be selected according to the provisions of Table 5. 6
Parts Name
Wide body, valve cover
Measuring tube
Internal components
Seals, packing
JB/T7252—94
General media
H, S partial pressure greater than 0.00035MPa media
Carbon pure steel
Austenitic stainless steel
Carbon steel
Carbon steel, ductile iron, etc. |tt||N-butadiene rubber, filled with PTFE
Stainless steel, ductile iron, low alloy steel (anti-corrosion treatment) Chloro rubber, filled with PTFE
5.8.2. The castings of the valve body and cover shall meet the requirements of GB12229 technical conditions. 5.8.3 For devices used in H,S gas, if the H,S partial pressure is greater than 0.00035MPa, the parts in contact with the medium in the device shall be made of materials resistant to H,S corrosion.
6 Test method
6.1 Shell performance test
6.1.1 Before the shell test, all parts of the device shall not be painted or coated with other coatings that may cover surface defects. 6.1.2 During the shell hydraulic test, the upstream and downstream ends shall be closed, and the advanced type shall be opened to clean the valve, and all packings and seals shall be pressed tightly enough to maintain the test pressure. During the test, the air in the body cavity should be exhausted and the pressure should be gradually increased to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.2 Sealing performance test
General requirements
The sealing test should be carried out after the shell test: Before the test, all parts shall not be painted or coated with other coatings that may conceal leakage: During the test, no external force that may affect the leakage of the sealing surface should be applied: Liquid sealing test leak detection method: Observe whether there is dripping and moisture at the sealing joint; Gas sealing test leak detection method: Pour clean water or apply soapy water or other similar solutions at the sealing joint, and observe the leakage of bubbles. 6.2.2 Sliding valve sealing test
After the valve body is assembled (without the orifice plate and guide plate, and without installing the pressure plate and top plate), close the upstream and downstream ends of the body, close the sliding valve, and press the packings and seals to maintain the test pressure. During the test, gradually pressurize to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged.
6.2.3 Orifice seal test
Press the orifice seal pair to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.2.4 Device seal test
Close the upstream and downstream ends. For devices with sliding valve mechanisms, the sliding valve must be opened, and the orifice plate and guide plate must be lifted to connect the upper and lower valve cavities. The packing seals must be tightened to maintain the test pressure. During the test, gradually pressurize to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.3 Device calibration
Device calibration should comply with the provisions of JJG267. 7 Inspection rules
7.1 Products must be inspected and qualified by the inspection department and accompanied by a product quality certificate before they can leave the factory. 7.2 Product inspection is divided into factory inspection and type inspection. "7.3 The factory inspection of products shall be in accordance with the provisions of Articles 6.1 and 6.2 of this standard and meet the requirements of Articles 5.2, 5.3 and 5.7 of this standard. t
JB/T7252-94
7.4 The type inspection items of products are the entire content of this standard. 7.5 Type inspection shall be carried out in any of the following situations: Product trial production and identification:
The product structure design has been greatly changed b.
When the national quality supervision agency proposes a type inspection requirement. 7.6 Sampling and judgment rules
7.6.1 Factory inspection should be carried out on each unit. Any unqualified item should be repaired. If it is still unqualified, the product is judged to be unqualified. 7.6.2 Type inspection should be carried out on one unit randomly selected from the qualified batch. If any item is unqualified, double sampling and re-inspection should be carried out. If the unqualified item is still unqualified, the batch of products is judged to be unqualified. 8 Standards Marking, packaging, transportation, storage
8.1 Marking
8.1.1 The valve body should be cast with the medium flow direction arrow, nominal diameter D% (mm), nominal pressure pn (MPaX10). 8.1.2 The sign should be placed in a conspicuous position on the device, and the sign should indicate: measurement mark and production license number, product name, model specification, actual value of measuring tube inner diameter D, applicable medium, applicable temperature, factory number, factory date, manufacturer name, trademark, etc. .1.3 The orifice plate shall be marked with: the measured value of the opening diameter d, the outer diameter, the thickness, the factory number, etc. 8.1.4 The measuring tube shall be marked with: the nominal pressure, the nominal diameter, the medium flow direction. The following contents shall be marked in a conspicuous position on the packaging box: 8.1.5
Shipping unit:
Name and address of the receiving unit;
Product name, model, specifications:
Total weight and length×width×height;
"Upward", "Moisture-proof\mark.
8.2 Packaging
8.2.1 After the device passes the test, the surface shall be cleaned of oil and dirt and coated with anti-rust; the inner cavity shall be cleaned of the remaining test medium: the machined surface shall be coated with anti-rust oil: blind plates shall be used at both ends to protect the flange sealing surface and the inner cavity. The device is fixed in a packaging box made of solid material, the orifice plate is packaged separately, and moisture-proof measures shall be taken in the box. 8.2.2
The following documents should be included in the packing box:
Product certificate:
Product manual:
Packing list:
List of random accessories.
8.3 Transportation
During transportation, the product should be protected from magnetic collision and rain. Inverted stacking is not allowed. 8.4 Storage
8.4.1 The device should be stored in a dry and ventilated room. Outdoor storage is not allowed. 8.4.2 Within 12 months from the date of delivery, under the normal operating conditions specified in the manual, the manufacturer shall be responsible for free warranty for damages caused by material defects, manufacturing quality, design, etc.2 During the shell hydraulic test, close the upstream and downstream ends. The advanced type must open the purge valve, and all packings and seals are pressed tightly enough to maintain the test pressure. During the test, the air in the body cavity should be removed and gradually pressurized to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.2 Sealing performance test
General requirements
The sealing test should be carried out after the shell test: Before the test, all parts shall not be painted or coated with other coatings that may cover leakage: During the test, no external force that may affect the leakage of the sealing surface should be applied: Liquid sealing test leak detection method: Observe whether there is dripping and moisture at the sealing joint; Gas sealing test leak detection method: Pour clean water or apply soapy water or other similar solutions at the sealing joint to observe the leakage of bubbles 6.2.2 Sliding valve sealing test
After the valve body is assembled (without the orifice plate and guide plate, and without the pressure plate and top plate), close the upstream and downstream ends of the body, close the sliding valve, and press all packings and seals to maintain the test pressure. During the test, gradually pressurize to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged.
6.2.3 Orifice seal test
Press the orifice seal pair to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.2.4 Device seal test
Close the upstream and downstream ends. For devices with sliding valve mechanisms, open the sliding valve, lift the orifice plate and guide plate, so that the upper and lower valve chambers are connected, and the packing seals are tightened to maintain the test pressure. During the test, gradually pressurize to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.3 Device calibration
Device calibration should comply with the provisions of JJG267. 7 Inspection rules
7.1 Products must be inspected and qualified by the inspection department and accompanied by a product quality certificate before they can leave the factory. 7.2 Product inspection is divided into factory inspection and type inspection. "7.3 The factory inspection of products shall be in accordance with the provisions of Articles 6.1 and 6.2 of this standard and meet the requirements of Articles 5.2, 5.3 and 5.7 of this standard. t
JB/T7252-94
7.4 The type inspection items of products are the entire content of this standard. 7.5 Type inspection shall be carried out in any of the following situations: Product trial production and identification:
The product structure design has been greatly changed b.
When the national quality supervision agency proposes a type inspection requirement. 7.6 Sampling and judgment rules
7.6.1 Factory inspection should be carried out on each unit. Any unqualified item should be repaired. If it is still unqualified, the product is judged to be unqualified. 7.6.2 Type inspection should be carried out on one unit randomly selected from the qualified batch. If any item is unqualified, double sampling and re-inspection should be carried out. If the unqualified item is still unqualified, the batch of products is judged to be unqualified. 8 Standards Marking, packaging, transportation, storage
8.1 Marking
8.1.1 The valve body should be cast with the medium flow direction arrow, nominal diameter D% (mm), nominal pressure pn (MPaX10). 8.1.2 The sign should be placed in a conspicuous position on the device, and the sign should indicate: measurement mark and production license number, product name, model specification, actual value of measuring tube inner diameter D, applicable medium, applicable temperature, factory number, factory date, manufacturer name, trademark, etc. .1.3 The orifice plate shall be marked with: the measured value of the opening diameter d, the outer diameter, the thickness, the factory number, etc. 8.1.4 The measuring tube shall be marked with: the nominal pressure, the nominal diameter, the medium flow direction. The following contents shall be marked in a conspicuous position on the packaging box: 8.1.5
Shipping unit:
Name and address of the receiving unit;
Product name, model, specifications:
Total weight and length×width×height;
"Upward", "Moisture-proof\mark.
8.2 Packaging
8.2.1 After the device passes the test, the surface shall be cleaned of oil and dirt and coated with anti-rust; the inner cavity shall be cleaned of the remaining test medium: the machined surface shall be coated with anti-rust oil: blind plates shall be used at both ends to protect the flange sealing surface and the inner cavity. The device is fixed in a packaging box made of solid material, the orifice plate is packaged separately, and moisture-proof measures shall be taken in the box. 8.2.2
The following documents should be included in the packing box:
Product certificate:
Product manual:
Packing list:
List of random accessories.
8.3 Transportation
During transportation, the product should be protected from magnetic collision and rain. Inverted stacking is not allowed. 8.4 Storage
8.4.1 The device should be stored in a dry and ventilated room. Outdoor storage is not allowed. 8.4.2 Within 12 months from the date of delivery, under the normal operating conditions specified in the manual, the manufacturer shall be responsible for free warranty for damages caused by material defects, manufacturing quality, design, etc.2 During the shell hydraulic test, close the upstream and downstream ends. The advanced type must open the purge valve, and all packings and seals are pressed tightly enough to maintain the test pressure. During the test, the air in the body cavity should be removed and gradually pressurized to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.2 Sealing performance test
General requirements
The sealing test should be carried out after the shell test: Before the test, all parts shall not be painted or coated with other coatings that may cover leakage: During the test, no external force that may affect the leakage of the sealing surface should be applied: Liquid sealing test leak detection method: Observe whether there is dripping and moisture at the sealing joint; Gas sealing test leak detection method: Pour clean water or apply soapy water or other similar solutions at the sealing joint to observe the leakage of bubbles 6.2.2 Sliding valve sealing test
After the valve body is assembled (without the orifice plate and guide plate, and without the pressure plate and top plate), close the upstream and downstream ends of the body, close the sliding valve, and press all packings and seals to maintain the test pressure. During the test, gradually pressurize to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged.
6.2.3 Orifice seal test
Press the orifice seal pair to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.2.4 Device seal test
Close the upstream and downstream ends. For devices with sliding valve mechanisms, the sliding valve must be opened, and the orifice plate and guide plate must be lifted to connect the upper and lower valve cavities. The packing seals must be tightened to maintain the test pressure. During the test, gradually pressurize to the test pressure. During the pressure maintenance and detection period, the test pressure should remain unchanged. 6.3 Device calibration
Device calibration should comply with the provisions of JJG267. 7 Inspection rules
7.1 Products must be inspected and qualified by the inspection department and accompanied by a product quality certificate before they can leave the factory. 7.2 Product inspection is divided into factory inspection and type inspection. "7.3 The factory inspection of products shall be in accordance with the provisions of Articles 6.1 and 6.2 of this standard and meet the requirements of Articles 5.2, 5.3 and 5.7 of this standard. t
JB/T7252-94
7.4 The type inspection items of products are the entire content of this standard. 7.5 Type inspection shall be carried out in any of the following situations: Product trial production and identification:
The product structure design has been greatly changed b.
When the national quality supervision agency proposes a type inspection requirement. 7.6 Sampling and judgment rules
7.6.1 Factory inspection should be carried out on each unit. Any unqualified item should be repaired. If it is still unqualified, the product is judged to be unqualified. 7.6.2 Type inspection should be carried out on one unit randomly selected from the qualified batch. If any item is unqualified, double sampling and re-inspection should be carried out. If the unqualified item is still unqualified, the batch of products is judged to be unqualified. 8 Standards Marking, packaging, transportation, storage
8.1 Marking
8.1.1 The valve body should be cast with the medium flow direction arrow, nominal diameter D% (mm), nominal pressure pn (MPaX10). 8.1.2 The sign should be placed in a conspicuous position on the device, and the sign should indicate: measurement mark and production license number, product name, model specification, actual value of measuring tube inner diameter D, applicable medium, applicable temperature, factory number, factory date, manufacturer name, trademark, etc. .1.3 The orifice plate shall be marked with: the measured value of the opening diameter d, the outer diameter, the thickness, the factory number, etc. 8.1.4 The measuring tube shall be marked with: the nominal pressure, the nominal diameter, the medium flow direction. The following contents shall be marked in a conspicuous position on the packaging box: 8.1.5
Shipping unit:bZxz.net
Name and address of the receiving unit;
Product name, model, specifications:
Total weight and length×width×height;
"Upward", "Moisture-proof\mark.
8.2 Packaging
8.2.1 After the device passes the test, the surface shall be cleaned of oil and dirt and coated with anti-rust; the inner cavity shall be cleaned of the remaining test medium: the machined surface shall be coated with anti-rust oil: blind plates shall be used at both ends to protect the flange sealing surface and the inner cavity. The device is fixed in a packaging box made of solid material, the orifice plate is packaged separately, and moisture-proof measures shall be taken in the box. 8.2.2
The following documents should be included in the packing box:
Product certificate:
Product manual:
Packing list:
List of random accessories.
8.3 Transportation
During transportation, the product should be protected from magnetic collision and rain. Inverted stacking is not allowed. 8.4 Storage
8.4.1 The device should be stored in a dry and ventilated room. Outdoor storage is not allowed. 8.4.2 Within 12 months from the date of delivery, under the normal operating conditions specified in the manual, the manufacturer shall be responsible for free warranty for damages caused by material defects, manufacturing quality, design, etc.4 Storage
8.4.1 The device should be stored in a dry and ventilated room. It is not allowed to be stored in the open air. 8.4.2 Within 12 months from the date of delivery, under the normal operating conditions specified in the manual, the manufacturer shall be responsible for free warranty for damages caused by material defects, manufacturing quality, design, etc.4 Storage
8.4.1 The device should be stored in a dry and ventilated room. It is not allowed to be stored in the open air. 8.4.2 Within 12 months from the date of delivery, under the normal operating conditions specified in the manual, the manufacturer shall be responsible for free warranty for damages caused by material defects, manufacturing quality, design, etc.
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