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General specifications of iron valves for urban water supply
1 Subject content and scope of application
This standard specifies the design, materials, test methods, signs and general requirements for the design of gate valves, butterfly valves, plug valves and globe valves for grey and ductile iron in urban water supply. If this standard is not specified, it shall comply with the national or industrial standards for valve products.
This standard applies the nominal pressure PN ≤ 1.6MPa, the working pressure Pw ≤ 1.6MPa, the driving mode is manual, electric, hydraulic or pneumatic, as a water supply valve for cutting or regulating in the process of water intake, water production and distribution in urban areas.
2 Reference standard GB 4216.1～4216.10 Gray cast iron pipe flange and gasket GB 9876 Rubber seal rubber for water supply and drainage pipe GB 12220 General valve mark GB 12221 Flange connection metal valve structure length GB 12222 Multi-turn valve drive connection GB 12223 Partial rotary valve drive unit connection GB 12226 General valve grey iron casting technical condition GB 12227 General valve ductile iron casting technical condition GB/T 12252 General valve supply requirements GB 12380.1～12380.6 Conveal integral ductile iron pipe flange GB/T 13927 General valve pressure test JB/T 5300 General valve material ZB J16 002 Valve electric device technical condition ZB J16 009 Valve pneumatic device technical condition
3 Technical requirements
3.1 housing (including valve body and bonnet)
3.1.1 Shell wall thickness
3.1.1.1 For urban water supply valves for underground transmission and distribution pipelines, when the nominal diameter is DN≤1200mm, the minimum wall thickness of the casing shall be designed according to the pressure level of 1MPa nominal pressure; when the DN>1200mm, the minimum wall of the casing The thickness can be designed according to the nominal pressure of 0.6MPa. When using the special needs, it can be designed according to 1MPa when ordering.
3.1.1.2 For urban water supply valves for water, water purification and application, the minimum wall thickness of the casing shall be in accordance with the general valve requirements and shall not be specified.
3.1.2 valve body
3.1.2.1 The connection dimensions of the flange shall be in accordance with the provisions of GB 4216.1 ~ 4216.10 or GB 12380.1 ~ 12380.6.
3.1.2.2 The structural length of the flanged connection valve shall be in accordance with the provisions of GB 12221.
3.1.2.3 For gate valves with a nominal diameter of DN ≥ 800 mm, a sewage tank should be provided on the side of the water inlet of the valve. The sump should have an inlet hole or a mud release port.
3.2 valve stem
3.2.1 Valve stem packing structure design should consider non-stop water replacement, maintenance and maintenance.
3.2.2 stem square head
For valves that are opened and closed with a detachable wrench, the dimensions of the stem square are as shown in Table 1.
Table 1
A square head
38×38mm
B square head
70mm
3.3 Operation
3.3.1 Operating direction of valve opening and closing
When facing the handwheel or the handle, clockwise rotation is the valve closing, and counterclockwise rotation is the valve opening. Special requirements are stated in the order contract.
3.3.2 Opening and closing operation torque
Under nominal pressure, the maximum operating torque required to open and close the valve shall not exceed the requirements of Table 2.
Table 2
Nominal diameter DN, mm
Maximum operating torque, N·m
500～800
720
>800
1440
When the opening and closing operation torque is greater than 1440 N·m, there should be a reduction gear.
3.3.3 opening and closing indicator
3.3.3.1 In addition to the open rod valve which can display the valve opening degree, the opening and closing indicator should be set for the urban water supply valve with the nominal diameter DN greater than 300mm. The position indicated by the opening and closing indicator shall be the same as the degree of opening and closing of the valve. When the operator faces the opening and closing member, the degree of opening and closing of the valve should be clearly observed.
3.3.3.2 For underground or open-air urban water supply valves with a nominal diameter DN greater than 300 mm, the drive section of the opening and closing indicator must be installed in a closed protective device.
3.3.3.3 The indicator should be installed securely, adjusted correctly, clearly indicated and durable.
3.3.4 Opening and closing mechanical limit device
For butterfly valves and plug valves for urban water supply, the opening and closing terminals shall be provided with mechanical limit devices, and the mechanical limit devices shall be able to withstand 2 times the maximum operating torque.
3.4 Drive unit
3.4.1 For electric-driven valves, the electric device shall comply with the provisions of ZB J16 002; for valves driven by air such as air, the pneumatic device shall be in accordance with the provisions of ZB J16 009.
3.4.2 Under normal operating conditions, the maximum control torque generated by the electric device shall be greater than or equal to 1.5 times the torque required by the valve and less than 2 times.
3.4.3 The limit switch and torque switch should be set in the open and closed positions of the motor drive.
3.4.4 When the hydraulically actuated valve is closed, there should be a buffer in the hydraulic system.
3.4.5 For valves such as gate valves and globe valves driven by electric, hydraulic and pneumatic forces, the dimensions of the connecting flange of the bracket and the drive unit shall comply with the provisions of GB 12222.
3.4.6 For valves such as butterfly valves and plug valves driven by electric, hydraulic and pneumatic forces, the dimensions of the connecting flange of the bracket and the drive unit shall comply with the provisions of GB 12223.
4 materials
4.1 All components, packings and seals of urban water supply valves shall not be contaminated with tap water. Among them, the rubber sealing ring rubber should meet the requirements of GB 9876.
4.2 Gray iron castings shall comply with the provisions of GB 12226; ductile iron castings shall comply with the provisions of GB 12227.
4.3 When a manufacturer uses a special coating to prevent corrosion, it should not contaminate the water source.
4.4 The stem shall be made of stainless steel containing not less than 11.5% chromium. Cast copper must not be used.
4.5 The fasteners used in the fixed parts of the valve are made of stainless steel.
4.6 The dial and the rotating pointer of the opening and closing indicator are made of corrosion-resistant materials such as stainless steel.
4.7 The materials of other parts of urban water supply valves shall be selected in accordance with JB/T 5300.
5 Test methods
5.1 Pressure test
5.1.1 The test acceptance of the urban water supply valve must be carried out one by one, and the test medium is water at normal temperature.
5.1.2 Before the test, the sealing surface must be cleaned. There should be no thin oil film layer on the valve seat to prevent scratches. The air in the cavity should be drained.
5.1.3 The test of urban water supply valves shall be carried out in accordance with the provisions of GB/T 13927.
5.1.4 The maximum allowable leakage of the non-metallic elastic sealing valve sealing test shall be carried out according to the Class A requirements of GB/T 13927; the maximum allowable leakage of the metal sealing valve sealing test shall be carried out according to the Class C requirements of GB/T 13927.
5.2 Drive test
Valves with drive units shall be assembled in the production plant and tested for opening and closing at rated pressure until the performance of the drive unit is acceptable.
6 Inspection rules The inspection of urban water supply valves is divided into factory inspection and type inspection.
6.1 Factory inspection
6.1.1 Valves for urban water supply shall be qualified by the inspection department of the production plant and shall be delivered with the certificate of conformity.
6.1.2 The factory inspection of valves for urban water supply shall be carried out one by one.
6.1.3 Factory inspection When there are no other additional items specified in the order contract, the following shall be included:
a. shell test;
b. Sealing test;
c. drive device test;
6.2 Type inspection
6.2.1 Type inspection should be carried out in one of the following cases:
a. Trial production and evaluation of new products;
b. Significant changes in design, process, materials, etc.
6.2.2 Type inspection shall include the following:
a. Factory inspection;
b. casting quality inspection;
c. Repeat the switch operation test at least 5 times.
7 signs
7.1 The marking of valves for urban water supply shall be carried out in accordance with the provisions of GB 12220.
7.2 The maximum working pressure must be indicated on the sign of the valve for urban water supply.
7.3 The special code in the model of the urban water supply valve is indicated by “Gâ€.
8 Packaging, transportation, storage
The packaging, transportation and storage of urban water supply valves shall be carried out in accordance with the provisions of GB/T 12252.
Additional information:
This standard was proposed by the Standardization Institute of the Ministry of Construction of the People's Republic of China.
This standard is under the jurisdiction of the North China Design Institute of China Municipal Engineering, which is managed by the Ministry of Construction of the People's Republic of China.
This standard was drafted by the Shanghai Public Utilities Research Institute.
The main drafters of this standard are Wang Shixi, Zhu Rongqing and Ying Wei.
This standard is entrusted to the Shanghai Public Utilities Research Institute for interpretation.
General technical requirements for iron valves for urban water supply
General technical requirements for iron valves for urban water supply in urban construction industry standards of the People's Republic of China CJ/T 3049-1995