This standard specifies the structure, parameters, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of needle stop valves. This standard is applicable to needle stop valves with nominal pressure PN ≤ 32.0 MPa and nominal diameter DN3 ~ 25 mm. Needle stop valves with other parameters can refer to it. JB/T 7747-1995 Needle stop valve JB/T7747-1995 standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Needle Stop Valve
Subject Content and Scope of Application
JBT7747.-.95
This standard specifies the structural type, parameters, technical requirements, test methods, inspection rules, markings, installation, transportation and storage of needle stop valves
This standard applies to needle stop valves with nominal pressure PX32.0MPa and nominal diameter IN3~25mm. Needle stop valves with other parameters can refer to it.
Reference Standards
GB 699
GB1018
GB1220
(G31221
G 730G
GB 7307
(GB9131
Ordinary thread
Ordinary thread
Basic size (diameter 1 ~ 600mm)
Tolerance and matching (diameter 1 ~ 355mm)
Technical conditions for high-quality magnetic structural steel
Nominal pressure of pipeline components
Stainless steel bars
Heat-resistant steel bars
Pipe threads sealed with Sichuan threads
Pipe threads sealed with non-threads
Steel pipe flanges
GB12220
GB12224
GB 12228
General valves
Steel valves
General valves
GB/T 12252Www.bzxZ.net
J3/\T 1751
J3/T5300
JB/T7748
Z13 JI6 006
Pressure-temperature grade
·General requirements
Technical conditions for carbon steel forgings
General valve supply requirements
Valve structural elements Socket welding connection and piping end dimensions General valve materials
Valve clearing and determination method
Valve testing and inspection
3 Structural types and parameters
3.1 Structural types
The main structural types of needle stop valves are shown in Figures 1, 2 and 3. Approved by the Ministry of Machinery Industry of the People's Republic of China on June 20, 1995 and implemented on January 1, 1996
JB/T 7747
1 Valve body: 2 Valve seat: 3-valve disc: 1. Valve cover: 5 Valve cup; 6 Packing pad; 7 Packing; 8 Packing gland:! Chen cover nut; 10 Handwheel Figure
1 Valve body; 2 Valve disc packing pad 1 Packing: 5... Valve stem 6 Valve cup nut. Lock nut 8 Handwheel Figure 2
3.2 Parameters
JB/T 7747- 95
1·Valve body, 2·Valve disc: 3·Valve cover 4·Valve stem. 5·Stuffing pad 6·Stuffing; 7·Stuffing gland: 8·Gland nut 9. Figure 3
3.2.1 The nominal diameter DN of the needle stop valve is 3.6.0.15.20.23mm. 3.2.2 The nominal pressure of the needle stop valve is in accordance with the provisions of G131048. 4 Technical requirements
4.1 Pressure and temperature grade
The pressure and temperature of the needle stop valve The pressure and temperature grades are in accordance with the provisions of GB9131. For materials whose pressure and temperature grades are not specified in GB9131, they shall be in accordance with the relevant standards or design regulations.
4.2 Valve body connection ends
4.2.1 The valve body connection ends are in the form of: internal threads at both ends, external threads at both ends, external threads at one end and internal threads at the other end, welding at both ends, etc. 4.2.2 The internal thread connection shall adopt a tapered pipe thread, which shall comply with the provisions of (iB7306, thread size! The corresponding relationship of nominal diameter 1V shall be in accordance with the provisions of Table 1.
Nominal diameter IN, mn
Thread size
4.2.3For external thread connection, pipe thread or ordinary thread shall be used. When pipe thread is used, it shall comply with the provisions of G137307; when ordinary thread is used, it shall comply with the provisions of G13196G13197
For external thread connection, ordinary thread shall be used. The connection end shall be equipped with joints, joint nuts and joint seals. 4.2.4For the general connection of welding connection, the dimensions of the connection end shall be in accordance with the provisions of J13/T1751. For the parts not specified in [B/T1751, the provisions of the contract or design shall be followed.
4.3Valve body and valve cover
JB/T 7747-95
4.3.1The minimum wall thickness of the valve body and valve cover shall be in accordance with the provisions of GB12224. 4.3.2 The valve body and valve cover are recommended to adopt an integral structure (Figure 2), or a split structure (see Figure 1 and Figure 3). The connection between the split structure valve body and valve cover must be reliable. 4.4 Valve disc
4.4.1 The valve disc and valve stem are designed as a whole, and the valve disc can also be assembled with the valve stem. After assembly, the valve disc should be able to rotate flexibly and be connected reliably. 4.4.2 The valve disc sealing surface can be directly processed on the valve disc, or it can be welded. The valve disc adopts a conical or spherical sealing surface. 4.5 Valve stem
The valve stem can be in the form of lower thread or thread. 4.5.2H
The threaded engagement length of the valve stem and valve cover or the valve stem and valve stem nut shall not be less than 1.4 times the diameter of the valve stem. 4.5.3 The thread of the valve stem and valve cover or the valve stem and valve stem nut shall comply with the provisions of GB16 and 197. 4.6 Valve seat
4.6.1 The valve seat and valve body can be connected by threaded connection, rolling connection or crimping connection, or can be directly added or welded on the valve body. 4.6.2 The connection thread of the valve seat with threaded connection shall comply with the provisions of GB196 and (FB197. 4.6.3 It is strictly forbidden to use sealants when assembling the valve seat, but light lubricating oil is allowed. 4.6.4 There should be an appropriate hardness difference between the seat and the valve disc. 4.7 Stuffing box Stuffing
4.7.1 The depth of the stuffing box shall not be less than the stuffing pad plus six turns of stuffing. When polyvinyl fluoride formed stuffing is used, the depth of the stuffing box shall not be less than the packing pad plus six turns of stuffing. When polyvinyl fluoride formed stuffing is used, the depth of the stuffing box shall not be less than the packing pad plus six turns of stuffing. No small ring packing,
4.7.2 The packing in the packing should be fully filled before the gland is pressed. For non-shaped packing, the section should be cut into 45°. And the cut of each ring of packing should be assembled according to the 120° variable fork.
4.8 Handwheel
The handwheel is closed in the clockwise direction. There should be an arrow indicating the closing direction and the word "off" on the rim, or an arrow between open and close and the words "beautiful".
4.9 Shell strength and sealing requirements
4.9.1 The shell test of the needle stop valve shall comply with the provisions of 2.13J16006, 4.9.2 The maximum allowable leakage of the needle stop valve sealing test shall comply with the provisions of ZBJ16006. 4.10 Cleanliness requirements
The total mass of impurities and dirt contained in the inner surface of the needle stop valve (including all internal parts) shall not exceed ten (.034.11 Materials
4.11.1 The materials of the main parts can be selected according to JB/T5300. 4.11.2 The materials of the valve body and valve cover shall comply with the provisions of GB12228, GB1220, GB1221 or GH699. 5 Test methods
5.1 The test method of the body test shall be in accordance with 5.2 The test method of sealing test shall be in accordance with the provisions of ZBJ16006. 5.3 The test method of shell material shall be in accordance with the provisions of GB12228, GB699, GB1220 or G131221. 5.4 The test method of cleanliness shall be in accordance with the provisions of JB/T7748. 6 Inspection rules
6.1 Inspection
6.1.1 Each needle stop valve must be inspected before leaving the factory. 6.1.2 The inspection items include:
Shell test;
Seal test.
JB/T7747 ---95
6.1.3 The shell test and seal test of each needle stop valve must comply with the provisions of Article 1.9 before it can be shipped. 6.2 Type inspection
6.2.1 Type inspection should generally be carried out in any of the following situations: a.
When a new product or old product is transferred to the factory for production; after formal production, if there are major changes in structure, materials, and processes that may affect product performance: during normal production, periodic inspection is carried out regularly or after a certain amount of production is accumulated: after a long-term suspension of production, when production is resumed; when the inspection results are significantly different from the last type inspection; when the national quality supervision agency proposes a requirement for type inspection. Type inspection is carried out by randomly selecting from the stock needle stop valves that have passed the inspection of the quality inspection department of the manufacturer, or randomly selecting from the needle stop valves that have been supplied to users but have not been used. The minimum number of units for sampling for each specification is 30, and the number of sampling units is 3. When the user is sampled.The number of units for sampling is not limited, and the number of sampling units is still 3. When conducting quality assessment on the entire series, the sampling inspection department can select 2 to 3 typical specifications from the series for inspection according to the situation. The number of units for sampling for each specification shall not be less than 30 units and the number of sampling units shall be 3.
Type inspection items include:
Shell test;
Seal test;
Shell material:
Cleanliness.
6.2.4 The shell test and seal test of each needle stop valve to be inspected must comply with the provisions of Article 4.9; the shell material must comply with the provisions of Article 4.11.2; the cleanliness shall comply with the provisions of Article 4.10. If the cleanliness index of one of the needle stop valves to be inspected is lower than the provisions of Article 4.10. It is allowed to draw a specified number of sampling units from the needle stop valves for sampling. When inspecting again, all inspection items must meet the requirements, otherwise it will be judged as unqualified.
7 Marking, packaging, transportation and storage
7.1 The marking of needle stop valves shall comply with the provisions of GB12220. 7.2 The packaging, transportation and storage of needle stop valves shall comply with the provisions of CB/T12252. Additional remarks:
This standard is proposed by the National Technical Committee for Valve Standardization. This standard is under the jurisdiction of the Hefei General Machinery Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Hefei General Machinery Research Institute of the Ministry of Machinery Industry and Tunxi High-Pressure Valve Factory. The main drafters of this standard are Qiu Xiaolai, Chen Yaqin, Li Baosheng, Pan Li and Shan Shuqin. 1
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