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API St 609:2009 pdf download

API St 609:2009 pdf download.Butterfly Valves: Double-flanged, Lug- andWafer-type.
For unidirectional valves, the marking shall be maximum unidirectional dead-end pressure .ux, where xxx represents 90 % of the lowest pressure in the appropriate direction determined from the prototypical tests. Additionally, the manufacturer will include this information in catalogs and installation, maintenance, and operating documents.
4.8 Operating Mechanisms
4.8.1 Levers, gear operators, handwheel, and automatic actuators shall be equipped with provisions to prevent movement of the disc from the desired set position dunng normal operating conditions. Normal operating conditions include throttling service when specified by the purchaser.
4.8.2 In addition to the requirements of the valve design, torque requirements for operation vary considerably with changes in flow media, operating pressure, and fluid velocity. Actuators shall be compatible with the operating torque requirements. It is recommended that conditions under which valves are to be operated are specified by the purchaser and are carefully evaluated by the manufacturer to determine the maximum resultant torque.
4.8.3 Valves shall be closed by turning the shaft and attached operating device (such as a handle) in the clockwise direction.
4.8.4 The operating mechanism (lever or gear) shall be designed such that the operator input force applied to handle or handwheel required to operate the valve at the manufacturer’s published torque requirement, does not exceed the operator input force capability values given in MSS SP-91, using a position multiplier of 0.5. In no case shall the input force exceed 360 N (80 Ib).
4.9 Electrical Continuity
When specified in the purchase order, valves shall incorporate an electrostatic feature that ensures electncal continuity between the shaft and the body or the shaft, body, and disc. The valve shall have electrical continuity across the discharge path, with a resistance of not more than 10 ohms. To test for continuity, a new dry valve shall be cycled at least five times, and the resistance shall be measured using a DC power source not exceeding 12 volts.
4.10 Packing Gland Bolting—Category B Valves Only
4.10.1 When used, gland bolting shall pass through holes in the gland. The use of open slots is not permitted in the cover flange, cover, adjuster, or gland.
4.10.2 Packing gland bolts shall be designed so that the bolt stresses shall not exceed one-third (1/3) of the minimum ultimate tensile strength of the bolt with a packing stress of 38 MPa (5500 psi) and a gland bolt temperature of 38°C (100 °F).
5 Materials
5.1 Body
The bodies of double-flanged, lug- and wafer-type butterfly valves shall be made of a material conforming to a
purchaser-selected material specification in accordance with the applicable ASME standard listed in Section 2.
5.2 Trim
5.2.1 All wetted materials shall be the manufacturer’s standard unless the purchaser specifies otherwise. Trim is defined as the seating surfaces of the body, disc, disc-to-shaft connection hardware (e.g. keys, pins, screws, etc.) and any internal fasteners that are in contact with the process fluid. Shaft and bushing materials shall be determined by the manufacturer, taking into account similar corrosion properties as the trim selection while also meeting design requirements of 4.5.
5.2.3 Trim shall not be welded to cast or ductile iron.
5.3 Seat Retainer—Category B Valves Only
Seat retainer plates, if applicable, shall be of the same nominal chemical composition as the body material. Retaining fasteners shall be at least intermediate strength as defined in ASME B16.5.
5.4 Packing or Shaft Seal Materials
Packing or shaft seal materials shall be suitable for the specified service at the valve’s pressure-temperature rating and shall be the manufacturer’s choice, unless otherwise specified in the purchase order.
5.5 Gland Bolting
Gland bolts shall be at least intermediate strength as defined in ASME B16.5.
5.6 Operating Mechanisms—Category B Valves Only
To prevent change of valve position, particularly in the case of a fire, materials for the valve handle or gear box
operator position device shall have a melting temperature of 760 °C (1400 °F) or higher.
6 Examination, Inspection, and Testing
6.1 Examination Requirements
The manufacturer shall examine all valves as specified in API 598.
6.2 Inspection by the Purchaser
If inspection by the purchaser is specified in the purchase order and a detailed procedure is not included, inspection shall be in accordance with API 598. If inspection is not specified in the purchase order, the valve shall be capable of meeting the inspection requirements described in API 598.
6.3 Pressure Tests
Each valve shall be pressure tested as specified in API 598.
6.4 Repair of Defects
6.4.1 When examination, inspection, or testing reveals defects in the body of a steel or alloy valve, the defects shall be repaired by the ASTM standard specified in the purchase order. If none are specified, the defects may be repaired as permitted by the most applicable ASTM material specification listed in Table 1 of ASME Bi 6.34.
6.4.2 When examination, inspection, or testing reveals defects in the body of a nonferrous valve, the defects may be repaired as permitted by the applicable ASTM specification for the material.
6.4.3 Welding, brazing, plugging, peening, or impregnation to repair defects in gray iron, ductile iron, or copper alloy castings is not permitted.


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