Classification of valves and valve testing standards

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　　Definition of valves: A general term for mechanical devices equipped with movable components, which are installed on pressure vessels, pressurized equipment, and their connecting pipelines to control the flow direction of the medium. Valves can be classified according to their working principles as follows: Gate valve: Also known as a gate plate valve, it belongs to the category of valves with forced sealing. Its sealing principle relies on the highly smooth and flat sealing surfaces of the gate and the valve seat, which fit together to prevent the flow of the medium; the sealing effect is enhanced by the use of a top mold, springs, or the shape of the gate itself. It mainly serves to block in the pipeline. When used as a cutoff medium, the flow path is direct when fully open, resulting in the lowest pressure loss during medium flow. 　　Globe valve: A globe valve, also known as a stop valve, belongs to the category of valves with forced sealing and is one of the most widely used types of valves. During opening and closing, the friction between the sealing surfaces is low, making it durable. The opening height is not large, it is simple to manufacture and easy to maintain. It is suitable not only for medium and low pressures but also for high pressures. As one of the most important shut-off valves, globe valves play a vital role in the aerospace industry. 　　Butterfly valve: A butterfly valve, also known as a flap valve, is a control valve with a simple structure. Its key component resembles a butterfly facing the wind and rotating freely. The disc of a butterfly valve is circular in shape, and it rotates around an axis located within the valve seat; the degree of rotation determines the degree to which the valve is open or closed. The valve disc is installed in the diameter direction of the pipeline. Within the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around its axis, with the rotation angle ranging from 0° to 90°; when it reaches 90°, the valve is in its fully open position. 　　Ball valve: A ball valve is a type of valve in which the closing element is driven by a valve stem and rotates around the axis of the valve. Ball valves are easy to operate, compact in size, can be manufactured in large diameters, offer reliable sealing, have a simple structure, and are easy to maintain. The sealing surface and the ball surface remain in a closed state, making them resistant to erosion by the medium. 　　Plug valve: A plug valve is a rotary valve in the form of a closure element or plug; it operates by rotating the plug around the center line of the valve body in order to achieve opening and closing. Its function is to block, divide the flow area, and change the direction of the medium. It has a simple structure, small external dimensions; only a 90-degree rotation is required for operation, and the fluid resistance is low. Its disadvantages are that the switch is difficult to operate, the sealing surface wears out easily, it gets stuck at high temperatures, and it is not suitable for regulating flow. 　　Check valve: Principle: A check valve is a valve that opens and closes automatically relying on the force of the fluid itself; its function is to prevent the medium from flowing in reverse. Under the pressure of the fluid moving in one direction, the valve disc opens; when the fluid moves in the opposite direction, it closes due to the pressure of the fluid and the weight of the valve disc, thereby blocking flow. Aliases: check valve, one-way valve, single-flow valve, etc. 　　Pressure reducing valve: A pressure reducing valve is an active valve that reduces the pressure of a fluid to a certain value; generally, the pressure downstream of the valve is less than 50% of the pressure upstream of it. There are many types of pressure relief valves, mainly piston-type and spring-diaphragm type. 　　Thermostat valve: A thermostat valve is also known as a steam trap, vapor-water valve, drain valve, return box, or return gate. Its function is to actively secrete the continuously generated condensate water, preventing steam from escaping. They are divided into thermodynamic steam traps and bell-type float steam traps, also known as bucket-type steam traps. 　　Safety valve: A safety valve is an important safety accessory on boilers, pressure vessels, and other pressurized equipment. The reliability of its operation and its performance are directly related to the safety of equipment and people, and are also closely connected to energy conservation and environmental protection. 　　The testing laboratory conducts pressure performance tests on valve products such as gate valves, globe valves, butterfly valves, check valves, ball valves, control valves, and pressure reducing valves. It also performs tests related to low-temperature operation, micro-leakage, chemical composition, mechanical properties, intergranular corrosion, chemical corrosion, welding procedure qualification, and metallographic examination. Help customers prevent valve damage and leaks in advance, thereby reducing environmental harm and losses for the customers. 　　Testing standards for valves:
GB/T 4213-2008 “Pneumatic control valves”
GB/T 8464-2008 “Steel and copper threaded valves”
GB/T 10869-2008 “Power plant control valves”
GB/T 12224-2005 “General requirements for steel valves”
GB/T 12232-2005 “Iron gate valves with flanged connections for general use”
GB/T 12233-2006 “Iron globe valves and lift check valves for general use”
GB/T 12234-2007 “Steel gate valves with bolted covers for the petroleum and natural gas industries”
GB/T 12235-2007 “Steel globe valves and lift check valves for the petroleum, petrochemical, and related industries”
GB/T 12236-2008 “Steel swing check valves for the petroleum, chemical, and related industries”
GB/T 12237-2007 “Steel ball valves for the petroleum, petrochemical, and related industries”
GB/T 12238-2008 “Flanged and wafer-type resilient-seated butterfly valves”
GB/T 12239-2008 “Industrial valves – Metal diaphragm valves”
GB/T 12240-2008 “Iron plug valves”
GB/T 12241-2005 “Safety valves – General requirements”
GB/T 12242-2005 “Pressure relief devices – Performance test methods”
GB/T 12243-2005 “Direct spring-loaded safety valves”
GB/T 12244-2006 “General requirements for pressure reducing valves”
GB/T 12245-2006 “Pressure reducing valves – Performance test methods”
GB/T 12246-2006 “Pilot-operated pressure reducing valves”
GB/T 12251-2005 “Steam traps – Test methods”
GB/T 13927-2008 “Industrial valves – Pressure testing”
GB/T 13932-1992 “Iron swing check valves for general use”
GB/T 19672-2005 “Technical specifications for pipeline valves”
GB/T 21385-2008 “Metal-sealed ball valves”
GB/T 21387-2008 “Axial flow check valves”
GB/T 22130-2008 “Steel plug valves”
GB/T 22653-2008 “Emergency shut-off valves for liquefied gas equipment”
GB/T 22654-2008 “Technical specifications for steam traps”
GB/T 24920-2010 “Steel pressure relief valves for the petrochemical industry”
GB/T 24925-2010 “Technical specifications for low-temperature valves”
JB/T 4730.2-2005 “Non-destructive testing of pressure equipment – Radiographic testing”
JB/T 4730.3-2005 “Non-destructive testing of pressure equipment – Ultrasonic testing”
JB/T 4730.4-2005 “Non-destructive testing of pressure equipment – Magnetic particle testing”
JB/T 4730.5-2005 “Non-destructive testing of pressure equipment – Penetrant testing”
JB/T 5296-1991 “General valves – Test methods for flow coefficient and flow resistance coefficient”
JB/T 5298-1991 “Steel slab gate valves for pipelines”
JB/T 6439-2008 “Magnetic particle testing of valve pressure parts”
JB/T 6440-2008 “Radiographic testing of cast steel valve pressure parts”
JB/T 6902-2008 “Liquid penetrant testing of valves”
JB/T 6903-2008 “Ultrasonic testing of forged steel valve parts”
JB/T 7248-2008 “Technical specifications for low-temperature steel castings used in valves”
JB/T 7747-2010 “Needle-type globe valves”
JB/T 7749-1995 “Technical specifications for low-temperature valves”
JB/T 7927-1999 “Appearance quality requirements for cast steel valve parts”
JB/T 8527-1997 “Metal-sealed butterfly valves”
JB/T 8691-1998 “Wafer-type knife gate valves”
JB/T 8858-2004 “Procedures for static pressure life testing of gate valves”
JB/T 8859-2004 “Procedures for static pressure life testing of globe valves”
JB/T 8860-2004 “Procedures for static pressure life testing of plug valves”
JB/T 8861-2004 “Specifications for static pressure life testing of ball valves”
JB/T 8863-2004 “Procedures for static pressure life testing of butterfly valves”
JB/T 8937-2010 “Wafer-type check valves”
JB/T 9092-1999 “Inspection and testing of valves”
API 594-2010 “Flanged, lugged, wafer-type, and butt-welded check valves”
API 598-2009 “Valve inspection and testing”
API 599-2007 “Steel plug valves with flanged, threaded, and welded connections”
API 600-2009 “Steel gate valves with flanged and butt-welded connections”
API 602-2009 “Steel gate valves, globe valves, and check valves with nominal sizes ≤ DN100 for the petroleum and natural gas industries”
API 603-2007 “Corrosion-resistant bolted bonnet gate valves – Flanged and butt-weld ends”
API 608-2008 “Metal ball valves with flanged, threaded, and welded connections”
API 609-2009 “Double-flanged, lugged, and wafer-type butterfly valves”
API 600-2015 “Steel gate valves with flanged and butt-welded connections”
API STD 602-2015 “Gate valves, globe valves, and check valves with sizes DN 100 (NPS 4) and smaller for the petroleum and natural gas industries”
API 622-2006 “Type testing of packing for process valves to prevent fugitive emissions”
API STD 623-2013 “Steel globe valves – Flanged and butt-weld ends, bolted bonnets”
API 624-2014 “Type testing of rising stem valves with FE graphite packing”
ANSI/API SPECIFICATION 6D-2010 “Pipeline valves”
HG 3158-2005 “Emergency shut-off valves for liquefied gas tank trucks”
BS EN 12266.1-2003 “Industrial valves – Pressure testing – Part 1: Pressure testing, test procedures, and acceptance criteria – Mandatory requirements”
BS EN 12266.2-2002 “Industrial valves – Pressure testing – Part 2: Tests, test procedures, and acceptance criteria – Additional requirements”
ISO 5208-2008 “Industrial valves – Pressure testing of metal valves”