API STD 603:2001 pdf download

API STD 603:2001 pdf download.Corrosion-Resistant, Bolted Bonnet Gate Valves-Flanged and Butt-Welding Ends.
The stem connection shall prevent the stein from turning or disengaging from the gate while the valve is in service. The stem train (stein. gate. stem nut. handwheel. and handwheel nut) shall be designed to fail outside the pressure boundary in the event of the application of excessive handwheel torque to over come a locked gate. The strength of the stem (in tension) outside the pressure boundary shall not be less than the calculated (theoretical) failure load based on the external thread root area and the specified minimum ultimate tensile strength of the stem material. The strength (in tension) of the stem-to-gate connection and of all parts of the stem within the pressure boundary shall be greater than the strength at the root of the external threads.
4.6.3 Valves shall have a stem operated by a rotating stein nut mounted at the top of the yoke. The stem nut shall have a hexagonal shank, a round shank with a keyway. or another drive of equivalent strength and durability for attachment to the handwheel. For valves larger than NPS 6 in Class ISO. NPS 4 in Class 300 or NPS 2 in Class 6(X) the stem nut arrangement shall be designed to:
a. permit the removal of the handwheel. without allowing the stem and gale to drop into the closed position. ii the hand- wheel is removed when the valve is in the open position.
b. allow the stem nut to be replaced. with the stem secured. without afTccting the pressure retaining capability of the bonnet assembly.
However, replacement under pressure is not recommended. When a threaded hushing is used to retain the stem nut, the bushing shall be retained by a weld or other suitable means to ensure that there is no movement during operation of the valve. Metal peening (staking) is not permitted.
4.6.4 The threads of the stem and stem nut shall be Acme type conforming to ASME B 1.5 or stub threads conforming to ASME BI.X (minor modifications are permitted for either thread), The Acme thread major diameter may be less by a maximum of 1/16 in. (1.6 mm) than the diameter of the stem that passes through the packing. On direct handwheel-operated valves, these threads shall be left-handed threads. (Clockwise rotation of the handwheel shall close the valve.)
4.6.5 Stern threads shall project outside the stem nut on a new closed valve by a distance that is at least equal to the required wear travel distance. The maximum projection distance of the stem thread shall be five times the wear travel distance for valves NPS 6 and smaller and three times the wear travel distance for valves NPS 8 and larger.
4.6.6 The stem shall have an integral conical or spherical backseat surface to seat against the bonnet backseat when the gate is fully open.
4.6.7 The stem shall have a surface finish Ra of 32 J4 in. (O.8Op m) or smoother in the area in contact with the packing.
If a lantern ring is furnished, the stuffing box shall he tapped opposite the center of the installed lantern ring and shall be fitted with a threaded solid round- or hex-head plug greater than or equal to NPS ‘/4. The plug shall be in accordance with the requirements of ASME B 16.11. The stuffing box shall have a boss as specified in ASME B 16.34. When a lantern ring is furnished, the stuffing box depth shall be at least equivalent to that of a minimum of three uncompressed rings of packing above the lantern ring and three uncompressed rings of packing below the lantern ring, plus the length of the lantern ring.
4.8 BOLTING
4.8.1 Bonnet and yoke bolting shall be headed bolts or continuously threaded stud bolts with heavy semi-finished hexagonal nuts confoniing to the requirements of ASME 1118.2.2. When headed bolts are used they shall be limited to class ISO in sizes NPS 8 and smaller and class 300 in sizes NPS 6 and smaller. Bonnet bolting for valves NPS 3/4 and smaller may utilize cap (see 4.2.4).
4.8.2 Gland bolting shall be headed bolts, hinged cycholts, or studs with hexagonal nuts.
4.8.3 Bolting that is 1 inch in diameter or smaller shall have coarse (UNC) threads. Bolting larger than 1 inch shall be 8-thread series (8 UNC). Bolt threads shall be Class 2A and nut threads Class 2B in accordance with ASME B 1.1. Ilowever. skids used for gland bolting shall be secured with a Class 5 interference-Ilt in accordance with ASME B 1.12.
4.9 OPERATION
4.9.1 Unless otherwise specified in the purchase order, the valve shall be operated directly by a handwhecl.
4.9.2 If chainwheel operation is required. the type of chain- wheel and chain required shall be specified in the purchase order.