Marking of valves
The mandatory and optional symbols for general-purpose valves are listed below. For manual valves, if the handwheel size is large enough, the handwheel should be equipped with an arrow indicating that the valve is closed or additional "open" "closed" words.
General valve marking items (GB12220): nominal diameter (DN); nominal pressure (PN); material code of pressurized parts; manufacturer's name or trademark; media flow arrow; sealing ring (gasket) code; limit temperature (℃); thread code; limit pressure; production plant number; standard number; melting furnace number; inner material code; station number; lining material code; quality and test mark. The inspector's seal; year and month of manufacture; flow characteristics.
General valve specific markings are specified as follows.
(1) 1-4 items in the table above are required to use the logo, for DN ≥ 50 mm valve, should be marked on the valve body; for DN ≤ 50 mm valve, marked on the body or nameplate, as specified by the product designer.
(2) Table 5 and 6 above only when a certain type of valve standards are required to use the logo, they should be marked on the valve body and flange respectively.
(3) If there are no special provisions in the various types of valve standards, the above table 7-19 is the need to choose to use the logo. When needed, can be marked on the valve body or label.
For pressure reducing valves, in addition to the markings on the valve body as specified in the above table, there should also be: a: factory date; b: applicable media; c: outlet pressure.
For steam traps, as specified in the table above, the sign can be located on the valve body or on the label. Signs for Steam Traps (GB12249) The following signs must be used.
Product model number; nominal diameter; nominal pressure; manufacturer's name and trademark; media flow direction; ZUI high working pressure; ZUI high working temperature.
Optional symbols: valve body material; ZUI high allowable pressure; ZUI high allowable temperature; ZUI high drainage temperature; factory number, date.
Marking of safety valve (GB12241)
Mark on the valve body: nominal diameter DN; valve body material; manufacturer's name or trademark; when the size or pressure level of the inlet and outlet connection part is equivalent, there should be an arrow indicating the direction of media flow
Mark on the plate: valve design allows ZUI high working temperature (℃); rectification pressure (MPa); based on the standard number manufacturer's benchmark model; rated displacement coefficient or for the benchmark media rated displacement; flow area (mm2); open height (mm) over the pressure percentage.
Valve symbols are similar, but there are still some differences, in order to avoid errors, this knowledge or we need to understand the master
