API RP 615:2010 pdf download

API RP 615:2010 pdf download.Valve Selection Guide.
5.1.4.1 General
Butterfly valves covered by API 609 are available in several configurations induding double flanged, and lug/wafer types that provde tight shutoff in the closed position but are also suitable foi flow regulation. Materials available include gray iron, ductile iron, bronze, steel, nickel-base alloy, and special alloys. These valves are intended for installation between flanges. Butterfly valves are defined in API 609 as two maor types. Category A (see 5.1.4.2) and Category B(see 5.1.4.3).
5.1.4.2 Category A Butterfly Valves
Manufacturer’s rated cold working pressure (CWP) butterfly valves, usually with a concentric disc and seat configuration. Sizes covered are NPS 2 through NPS 48 for valves having ASME Class 125 or Class 150 flange bolting patterns. These valves are often lined with a nonmetallic material that may extend over the flange faces to serve as a gasket material. See Figure A.10 fora typical Category A Butterfly Valve.
5.1.4.3 Category B Butterfly Valves
Pressure-temperature-rated butterfly valves that have an offset seat and either an eccentric o’ a concentric disc configuration are available in Class 150. 300, and 600. These valves may have a seat rating less than the body rating. API 609 lists the minimum seat pressure-temperature ratings for PTFE and reinforced PTFE materials, Seat rating for other materials Is determined by agreement with the manufacturer.
The body rating is determined from ASME Standards B16.34 (standard dass), B16.42 for ductile iron, or B16.24 for cast copper alloys depending on the body material. Category B butterfly valves are specified in sizes up to NPS 48 for double flanged designs and up to NPS 24 for lug and water designs. The lug type or ‘single flanged has bolting lugs provided threaded as standard but optionally may be ordered drilled through. Category B valves are known as Thigh performance” butterfly valves. See Figure A.11 for a typical category B Butterfly Valve.
5.1.4.4 Triple Offset Designs
In addition to the double offset disc designs, there is also the triple offset design, which uses an angled-seat geometry to allow shaft dosing torque to compress the sealing element more tightly to provide for a better seal. Since the body seat has a complex geometry. repair or replacement of a damaged seat may require special equipment. See Figure A.12 for an example of a triple offset design.
5.1.4.5 OrientatIon Considerations
Although butterfly valves are operable in any orientation, the preferred orientation for butterfly valves is with the stem horizontal to avoid debris collection and bearing wear that may occur with the stern vertical.
5.1.5 Globe Valves
Although mainly considered for throttling service, globe valves are another valve type that may be used as a block valve. These will be discussed in more detail In 5.3.