JB/T 13887-2020 Automatic recirculation valves
1 Scope
This standard specifies the terms and definitions, structural types, technical requirements, materials, examination and test methods, inspection rules, marking, packaging and transport of automatic recirculation valves.
This standard is applicable to automatic recirculation valves with nominal pressures of PN16–400, nominal diameters of DN25–500, pressure grades of Class150–2500, nominal pipe sizes of NPS1–20, and medium temperatures of -29–538 °C, which are used on steel T-shaped tee joint structures for petroleum, chemical, electric power and related industries.
It may also serve as a reference for other types of automatic recirculation valves.
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 150.3 Pressure vessels - Part 3: Design
GB/T 152.4 Fasteners - Counterbores for hexagon bolts and nuts
GB/T 196 General purpose metric screw threads - Basic dimensions
GB/T 197 General purpose metric screw threads - Tolerances
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature
GB/T 1239.2-2009 Cold coiled helical springs technical specifications - Part 2: Compressions spring
GB/T 4622.3 Specification of spiral wound gaskets
GB/T 6175 Hexagon nuts, style 2
GB/T 9124
(All parts) Steel pipe flanges
GB/T 9125 Fasteners for steel pipe flange joints
GB/T 12220 Industrial valves - Marking
GB/T 12221 Metal valves - Face to face, end to end, center to face and center to end dimensions
GB/T 12224 General requirements for industrial steel valves
GB/T 12229 General purpose industrial valves - Specification of carbon steel castings
GB/T 12230 General purpose industrial valves - Specification of stainless steel castings
GB/T 12235 Steel globe valves and lift check valve for petroleum, petrochemical and allied industries
GB/T 13927-2008 Industrial valves - Pressure testing
GB/T 30832 Valves - Test method of flow coefficient and flow resistance coefficient
JB/T 106 Valves marking and paint
JB/T 6438 Technical requirements for plasma arc overlaying welding for valve sealing surface
JB/T 6440 Methods of radiographic examination for steel castings valves
NB/T 47008 Carbon and alloy steel forgings for pressure equipment
NB/T 47010 Stainless and heat-resisting steel forgings for pressure equipment
NB/T 47013.5 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
automatic recirculation valve
automatic valve with a bypass, installed at the pump outlet, usually in a T-shaped tee structure; on the main, it is a flow-sensitive check valve that prevents backflow of the medium; on the bypass, it is a pressure-reducing valve that provides the minimum continuous flow necessary for the safe operation of the pump; the main and the bypass can switch automatically
3.2
minimum continuous flow
minimum continuous stable flow or minimum flow of the pump under minimum continuous thermal control flow conditions as specified in GB/T 3215-2007, generally provided by the pump manufacturer
3.3
main flow pressure drop
pressure difference between the inlet and the outlet when the main flow of the pump is at the rated flow of the pump
3.4
switch point
main flow at which the bypass is just closed
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Structural types
5 Technical requirements
5.1 Pressure-temperature rating
5.2 Bypass nominal dimensions
5.3 Structural length
5.4 Connection ends
5.5 Shell
5.6 Check valve disc
5.7 Sealing surface
5.8 Connection between the valve body and bonnet
5.9 Connecting flanges
5.10 Spring
5.11 Main flow pressure drop
5.12 Switch point
5.13 Bypass flow coefficient
5.14 Bypass pressure-reducing performance
5.15 Noise prediction
5.16 Non-destructive testing
5.17 Shell strength test
5.18 Sealing test
6 Materials
6.1 Shell
6.2 Check valve discs
6.3 Sealing surface overlaying welding
6.4 Internal components of bypass
6.5 Connecting gaskets
6.6 Connecting fasteners
7 Inspection and test methods
7.1 Material composition analysis
7.2 Mechanical properties of shell materials
7.3 Main flow pressure drop
7.4 Switch point
7.5 Bypass flow coefficient
7.6 Shell strength test
7.7 Sealing test
7.8 Marking
7.9 Non-destructive testing
8 Inspection rules
8.1 End-of-manufacturing inspection
8.2 Type test
9 Marking, packaging, storage and transport
9.1 Marking
9.2 Packaging, storage and transport
Annex A (Informative) Table of parameters for the selection of automatic recirculation valves
Bibliography
Figure 1 Typical structure of low-pressure automatic recirculation valves
Figure 2 Typical structure of high-pressure automatic recirculation valves
Table 1 Bypass nominal dimensions
Table 2 Structural length of the main
Table 3 Minimum wall thicknesses of the valve body
Table 4 Minimum diameter of connecting studs
Table 5 Overlaying welding materials of sealing surface
Table 6 Inspection items, technical requirements and test methods
Table A.1 Table of parameters for the selection of automatic recirculation valves
