Technical requirements for pre-insulated directly buried valve of urban heating
1 Scope
This standard specifies the general requirements, requirements, test methods, inspection rules, marking, transportation and storage of pre-insulated directly buried valve of urban heating.
This standard is applicable to the manufacturing and inspection of pre-insulated directly buried valve with continuous operating temperatures greater than or equal to 4°C, less than or equal to 120°C, occasional peak temperatures less than or equal to 140°C, and working pressures less than or equal to 2.5 MPa.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1224 General requirements for industrial steel valves
GB/T 13927-2008 Industrial valves - Pressure testing
GB/T 29046 Test methods of technical specification for pre-insulated directly buried district heating pipes
GB/T 29047 Prefabricated directly buried insulating pipes and fittings with polyurethane foamed-plastics and high density polyethylene casing pipes
CJJ/T 81 Technical specification for directly buried hot-water heating pipeline in city
JB/T 12006 Steel pipe welded ball valve
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
valve assembly
components composed of high density polyethylene casing pipe (hereinafter referred to as casing pipe), polyurethane foamed-plastics insulating layer (hereinafter referred to as insulating layer), steel welded valve and valve extension pipes
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3.2
valve extension pipes
steel pipes welded at both ends of the valve for convenience of thermal insulation and installation of the valve
3.3
welding end on valve
end at the joint between the valve extension pipe and the working steel pipe
3.4
breakaway thrust/breakaway torque
torque required to open and close the valve at maximum pressure difference
3.5
bending moment
moment generated when the valve is subjected to bending load
3.6
valve unload
state of the valve without axial force and bending moment
4 General requirements
4.1 The schematic diagram of valve assembly structure is shown in Figure 1.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
5 Requirements
5.1 Valves
5.2 Valve assembly
6 Test methods
6.1 Valves
6.2 Valve assembly
7 Inspection rules
7.1 Inspection classification
7.2 End-of-manufacturing inspection
7.3 Type inspection
8 Marking, transportation and storage
8.1 Marking
8.2 Transportation
8.3 Storage
Annex A (Normative) Axial force and bending moment table
Annex B (Normative) Test method for radial bending moment
Bibliography
