API 594:2004 pdf download

API 594:2004 pdf download.Check Valves: Flanged, Lug, Wafer and Butt-welding.
The total cross-sectional area of the bolts shall be in accordance with the requirements of ASME B 16.34.
4.1.16 When valst design utilires a stem that estends beyond the pressure boundary. it shall be provided with a means so that, in the esent of a structural failure of stem-to- closure attachment items, the stem will not he ejected through the pressure boundary while the salve is under pressure.
4.2 PLATES AND DISC
Valves are classitied as follosss:
a. A single-plate valve has a plate or disc that closes the valve when how reversal or gravity forces the plate or disc against the valve-body seat. This closure may he aided by the use of springs or other devices.
b. A dual-plate valve has plates that close the valve with the assLstancc of one or more springs, when flow reversal forces the plates against the valve’body seat.
c. For Type ‘A’ single-plate valves and Type ‘B’ valves. when a nut is used to assemble the disc or plate to the hinge arm, the nut shall be secured to prevent separation; the use of a single tack weld, lock washer or luck nut are not acceptable means.
4.3 SEATiNG SURFACES
4.3.1 The body and plate or disc seating surfaces may be of deposited weld metal, integral metal, mechanically retained metal, or a resilient material. On bpe ‘A’ single-plate salves and ‘type ‘B’ valves, a resilient seal ring ‘nay be fitted either to the body or plate seat as specified by the purchaser. The ring shall be designed to give a full metal to metal seal if the resilient seal is inoperative or rentosed,
4.3.2 Welding is not pennitted on cast iron or ductile iron.
43.3 hlraiing is permitted on cast iron and ductile iron only for attaching seating surfaces to the body or the plate and only if agreed to by the purchaser and the manufacturer. Furnace hraiing is the only type of hrasing permitted and maybe used only if the parts are heated under closely controlled conditions, in a uniform manner, and to a temperature no higher than the lower critical temperature of the base material. Cooling shall be in the furnace or in still air.
44 EXTERNAL BOLTS AND ThREADED HOLES
4.4.1 Bolts and threaded holes with a diameter I in- or smaller shall have coarse (UNCI threads. Those larger than I in. diameter shall be of the eight-thread series IS UN).
Bolt threads shall he Class 2A, and nut threads shall be Class 2B. Threads shall conform toASMli B 1.1.
8.2 VALVE OPENINGS
8.2.1 Esept for the ends 01 small. indisidually packaged valves. valve ends shall be covered to protect the gasket surfaces and valve internals during shipment and storage. The protective covei shall be wood, wood tibet. plastic, or metal and securely anached to the salve ends by bolts. Mccl straps. or suitable friction lorking devices. The covers shall be no smaller than the outside diameter of the valve ends and designed so that the valves cannot be installed without cornplete removal of the covers.
8.2.2 All threaded connections in the salve body shall be lifled with solid, fully tightened plugs conforming to ASME 1116.11. or ASME 1116.14. Gray iron or malleable iron plugs shall only be used on gray iron or ductile iron salves respectively.
8.3 PACKAGING
8.3.1 Whcn espot’t packaging is not specified in the purchase order. valves may he shipped loose. pallcmied. or packed in a hos or crate. Valves shall he packaged to prevent damage during shipment.
8.3.2 Whcn the purchase order specifies cspon packaging. salws shall be shipped in wooden hoses or crates, individually or collectively, and packed to present their shifting within the package. (The shipping agent representing the pwvhaser will normally provide detailed instructions.)
9 Recommended Spare Parts
4 lam specitied on the purchase order, the s’cndor shall submit a complete list of spare parts. The list shall include cross-sectional or assembly-type drawings for idcnlihcation with part numbers.