API 594:2010 pdf download

API 594:2010 pdf download.Check Valves: Flanged, Lug, Wafer, and Butt-welding.
5.1.3.1 Welding a flange to a valve body shall be by full penetration butt-welding. The welding procedure and the welder or welding operator shall be qualified in accordance with ASME-BPVC, Section IX. Valves having flanges attached by welding shall meet the requirements of paragraph 2.1.6 of ASME B16.34.
5.1.3.2 Integral or other alignment rings (centering backing rings) used to facilitate welding shall be completely removed after the weld is completed.
5.1.4 Type ‘A’ valves larger than DN 600 (NPS 24) in Classes 150, 300, and 600 shall have body-flange bolt patterns suitable for the lug or double-flanged type, outside diameters suitable for the wafer type, and gasket surface dimensions compatible with the flange standards specified in the purchase order.
5.1.5 Flange faces with ring-joint grooves shall conform to the dimensions shown in either ASME B16.5 or ASME B16.47, as applicable.
5.1.6 Flange facing finishes shall be:
— Type ‘A’ valves only: gray iron and ductile iron valves shall be finished as specified in MSS SP-6;
— Type ‘A’ and Type ‘B’ valves; steel, nickel-alloy, and other alloy valves shall be finished as specified in ASME
B16.5.
5.1.7 Auxiliary connections are required only when specified by the purchaser:
— Type ‘A’ valves only: For gray iron and ductile iron valves the size, type, and location of auxiliary connections shall be the manufacturer’s standard unless otherwise agreed by the manufacturer and the purchaser.
— Type ‘A’ and Type ‘B’ valves; For steel, nickel alloy and other alloy valves auxiliary connections shall comply with the requirements of ASME B16.34, Section 6.3. The location and designation of auxiliary connections shall be manufacturer’s standard for Type ‘A’ valves and per ASME Bi 6.34, Figure 1(b) for Type ‘B’ valves.
5.1.8 The valve may have either an integral or a removable seat ring. Sealing compounds or greases shall not be used when assembling seat rings; however, a light lubricant having a viscosity no greater than kerosene may be used to prevent galling of mating threaded surfaces.
5.1.9 Tapped test openings are permitted only if specified in the purchase order. If a tap is made in the body for testing the valve, the tap shall not be larger than DN 15 (NPS 1/2). After testing. the tapped hole shall be fitted with an ASME B16.11 or ASME 816.14 threaded solid round or hex-head plug. The test tap may require a boss to provide the minimum thread engagement, as specified in ASME B16.34.
5.1.1 0 For Type ‘A’ valves a tapped blind hole shall be provided in the body of valves which are either NPS 10 or larger, or which weigh more than 50 lb (23 kg), for attachment of an eye bolt or equivalent lifting device. The hole shall be tapped with a coarse (UNC) Class 2B thread, conforming to ASME BI .1. If an eyebolt is specified in the purchase order, it shall conform to ASME 818.15.
5.1.11 Unless otherwise specified in the purchase order, for Type ‘A’ valves the lugs of lug type valves and flanges of double-flanged type valves shall be provided with non-threaded (drilled) bolt clearance holes.
5.1.12 Butt-welding ends shall conform to the requirements of ASME B16.25 for the bore specified for use without backing rings.
5.1.13 Conversion of a flanged end to a butt-welding end is not permitted except by agreement between the purchaser and manufacturer.
5.6 Gasket Surface
Fasteners in the flange seating surface shall be recessed to or below the flange gasket level. Interruptions in the seating area of a centered ASME B16.20 spiral-wound gasket for valve sizes DN 150 (NPS 6) and larger shall not exceed the limitations given in Figure 1. The permissible surface interruptions on smaller size valves shall be as agreed between purchaser and manufacturer but shall not exceed 50 % of the gasket seating width.
NOTE The degree ol Interruption may affect the sealability of a spiralwound gasket.
6 Material
6.1 Body and Cover
The body of Type ‘A valves and the body and cover of Type ‘B’ valves shall be made of a material conforming to a purchaser selected material specification listed in the applicable ASME standard as referenced in 4.1.
6.2 Plateand Disc
Plate or disc shall be made of a material whose corrosion resistance is greater than or equal to that of the valve body.
6.3 Cover Gasket (Type ‘B’ Valves)
6.3.1 The cover flange gasket shall be:
— solid metal, corrugated or flat;
— filled metal jacketed, corrugated or flat;
— metal ring joint:
— spiral-wound metal gasket with filler and a centering/compression ring.