Valve Practical Signs

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The mandatory and optional flag items for general-purpose valves are listed below. For manual valves, if the size of the handwheel is large enough, the handwheel should be provided with an arrow indicating the valve is closed or the words “open” and “closed” are added.

General valve marking project (GB12220):Nominal diameter (DN);Nominal pressure (PN);Material code of pressure parts;Manufacturer’s name or trademark;the arrow of the medium flow direction;Sealing ring (pad) code;Limit temperature (℃);thread code;ultimate pressure;The serial number of the manufacturer;Standard;melting furnace number;Internal material code;work station number;Lining material code;quality and test marks;Inspector’s stamp;Year and month of manufacture;flow characteristics.

The specific signs of general valves are specified as follows:

(1) Items 1-4 in the above table are the signs that must be used. For valves with DN ≥ 50mm, they should be marked on the valve body;For valves with DN≤50mm, whether to mark on the valve body or on the nameplate is specified by the product designer

(2) Items 5 and 6 in the above table are the only signs that must be used when there is such a requirement in a certain type of valve standard, and they should be marked on the valve body and flange respectively.

(3) If there are no special provisions in various valve standards, the above items 7-19 are the signs to be used as needed. When required, can be marked on the valve body or on the plate.

For the pressure reducing valve, in addition to the requirements in the above table, the mark on the valve body should also include: a: date of manufacture; b: applicable medium; c: outlet pressure.

The steam trap is specified in the following table, and the mark can be set on the valve body or on the sign. Signs of steam traps (GB12249) must be used:

Product model; nominal diameter; nominal pressure; manufacturer’s name and trademark; medium flow direction; maximum working pressure; maximum working temperature.

Optional signs: valve body material; maximum allowable pressure; maximum allowable temperature; maximum discharge temperature; factory serial number and date.

Safety valve logo (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 parts are equivalent, there should be an arrow indicating the flow direction of the medium

Marks on the plate: the maximum allowable working temperature of the valve design (℃); the set pressure (MPa); the reference model of the manufacturer based on the standard number; the rated displacement coefficient or the rated displacement for the reference medium; flow area (mm2 ); the opening height (mm) exceeds the pressure percentage.

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