ASTM F1565:19 pdf download

ASTM F1565:2019 pdf download.Standard Specification for Pressure-Reducing Valves for Steam Service.
(I) Through-bolts or studs threaded the entire length and fitted with a nut on each end. Threads on bolts, studs, and nuts shall be Class 2 fit in accordance with ASME B 1. 1.
(2) Studs with interference fit at the tap end sufficient to preclude inadvertent backing out and a Class 2 fit at the nut end.
Bonnet and bottom cover shall be located by body guiding (that is. a close tolerance fit between machined diameters on the body, bonnet, and bottom cover) rather than depending on studs or bolts for location. Spiral wound gaskets shall be fully retained, and the joints shall have metal-to-metal take-up to provide controlled compression of the gaskets. To assure easy gasket removal, not more than two gasket-retaining faces for each gasket shall be formed on a single part. Joint design shall assure parallel alignment of the guide bushings. Sufficient bolting area shall be provided to maintain metal-to-metal make-up over at least a three-year period. Bearing surface of nuts and their respective surfaces on the valve shall he finished machi ned.
6. 1 . 10 Body construction—Valve bodies shall be machined from a one-piece casting or forging and shall he of basic globe configurations with in-line inlet and outlet ports. Steam lines, except for the external downstream pressure sensing line (where used), shall be internally ported in the body and bonnet. Body passages shall produce gradual changes in flow direction so as to reduce any effects of concentrated impingement and 90° turns. In portions of the valve subject to velocity increases and flow direction changes, such as immediately downstream of the seat, the design shall eliminate direct impingement against the walls at close range.
6.1.11 Control connections—Where external downstream sensing is used, a ½-in, iron pipe size (i.p.s.) flanged connection, which is either cast or forged integral with the body or bonnet or welded, shall be provided.
6. 1 . 1 2 Internal Trim—Internal trim (except welded or brazed-in seat rings) shall be readily replaceable without requiring removal of the valve body from the line. The main plug or disk shall be single seated. Guiding of the plug or disk shall prevent binding or seizing and insure proper seating under all design conditions. This requirement shall be maintained with interchangeable parts and under any tolerance stack-up condition.
6. 1 . 13 Set Point Adjustment—Means shall be provided for adjusting the set point through the specified range, with the valve under pressure. The adjusting or loading device shall be safeguarded against accidental change in set point.
6.1.14 Valve Specification Coding—Basic valve design features shall he specified and recorded using the following valve coding system. The valve specification code contains four fields of information, which describe the construction features of the valve. Each of these four fields are further assigned their respective codes in accordance with Tables 2-5.