AIL Gate Valves conform to API Standard 600 for Steel Gate Valves - Flanged and Butt welding ends. The valves are exceptionally sturdy, rugged and durable.

Body and Bonnet The body is cast with uniform sections and generous radius fillets to prevent stress concentrations. The body has a straight through port without recess except between the seats, which ensures minimum turbulence, erosion and resistance to flow. Long guide ribs in the body match with the full length guide slots in the wedge for accurate alignment and guidance. The bolted bonnet, Outside Screw and Yoke type is fitted with a back seat bush to guide the stem and provide a back seat when the valve is fully open and under pressure. The Yoke is cast integral with the bonnet in valves up to 12" (300mm) size. This ensures accurate alignment of the stem and reduces weight. The Body-Bonnet joint for ASME Class 150 valves is oval in shape and flat faced. In ASME Class 300 and 600 valves, the bonnet joint is circular in shape and male-female type. Valves in 2" (50mm) size have a square body-bonnet configuration.

Flexible Wedge AIL's one piece cast flexible wedge minimizes stress concentration. Wedge flexibility assures tight seating over a wide range of differential pressures and temperatures. It also adjusts for slight mis-alignments caused by pipeline deflections. The stem to wedge thrust is applied close to the wedge centre. This reduces lateral stem loading and provides for more accurate disc movement. Seat Rings Seal welded seat rings offer minimum pressure drop. Leakage through the path between the seat rings and the body is also eliminated. The seating surfaces are ground and lapped. Seat rings of gate valves in 2" (50mm) size are flared into the body.

Stem The heat treated 13% Cr. Steel stem has accurate threads for wide engagement with the yoke sleeve. The heavy forged 'T' head engages with the T-slot in the wedge. The stem also has an integral self adjusting radial back seat shoulder which matches with the back seat bush in the bonnet. The stem surface is precisely machined and ground to reduce friction which minimizes leakage and extends stem packing life. Stem to wedge connnection meets the requirements as per API Recommended Practice 591-Appendix 'C' Stuffing Box The stuffing Box with a smooth surface finish holds a minimum 5 packing rings. This ensures tightness and extends the life of packing rings. ASME Class 300 and 600 valves can be supplied with a lantern ring arrangement on request.

Yoke Sleeve Cast in austenitic ductile iron alloy to provide resistance to heat, corrosion and wear, this alloy is also copper free. The long thread engagement assures accurate alignment of the stem. In ASME Class 600 valves of size 6" (150mm) and above, the Yoke sleeve is mounted on thrust bearings to facilitate easy operation. Flange drilling and facing finish Standard range of AIL flanged valves in sizes up to 24" (600mm) are finished with end flanges faced, drilled and spot faced to ASME B16.5 RF. Class 600 valves are offered with RTJ end flanges on request. Flanges of larger size valves are drilled as per ASME B16.47 Series A. The standard finish offered on the raised face is 125-250 µ in Ra (AARH) spiral serration. Concentric serration and smooth finish can also be offered on request. Operation All valves are provided with a steel/ductile iron/malleable iron handwheel for manual operation. Valves in size 24" C1 150; 20" C1 300; 16" C1 600 and above are offered with a fully enclosed bevel gear unit as a standard. Standards AIL Cast Steel Gate Valves conform to API Standard 600 and applicable requirements of BS 1414 standard.

MATERIAL OF CONSTRUCTION for standard valve Item No. Description Material  1  Body  ASTM A216 Gr.WCB  2  Body Seat Ring  ASTM A105 + HF  3  Wedge  ASTM A216 Gr.WCB  + 13% Cr. Steel  4  Stem  ASTM A182 Gr.F6a  5  Gasket  ASTM A308  6  Bonnet  ASTM A216 Gr.WCB  7  Stud  ASTM A193 Gr. B7  8  Stud Nut  ASTM A194 Gr. 2H  9  Backseat Bush  13% Cr. 10  Packing  Graphite with braided  end rings 11  Gland  Steel 12  Gland Flange  ASTM A105/A216  Gr. WCB 13  Eye Bolt  Cr-Mo Steel 14  Eye Bolt Nut  ASTM A563 Gr. B 15  Groove Pin  Steel 16  Yoke Sleeve  (Stem Nut)  ASTM A439  Type D2 17  Grease Fitting  Steel 18  Retainer Nut  Steel/Ductile Iron/  Malleable Iron 19  Handwheel 20  Handwheel Nut *  Name Plate  SS 304

FIGURE No. 113 - 8

AIL ASME CLASS 300 GATE VALVE

AIL ASME CLASS 600 GATE VALVE

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