Specifications Part 1 - Water Supply, Sewerage and Tube Well Works
Specifications Part 1 - Water Supply, Sewerage and Tube Well Works
Specifications Part 1 - Water Supply, Sewerage and Tube Well Works
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8.29.1.2 The total length of the valve should be as per the table below:Diameter (mm)Total length ofvalve (mm)500 1850550 1850600 1920650 1950700 2000750 2100800 2300850 2300900 2150950 23001000 2400Dim Tol +/- 15 mm max8.29.1.3 The valve should be provided with 2 to 4 (four) Nos. of h<strong>and</strong> holes of adequatesize to facilitate insertion <strong>and</strong> removal of springs by h<strong>and</strong> (if required) withoutremoving the valve from line. A suitable cover shall be provided on each of theh<strong>and</strong> hole.8.29.1.4 A 'Bypass pipe' with a Valve of 80 NB for 500 - 650 mm, 100 NB for 700 950mm <strong>and</strong> 150 NB for 1000 mm <strong>and</strong> above should be provided for connectingupstream <strong>and</strong> downstream sides of Zero Velocity valve should be provided.Minimum two plugs should be provided to mount Pressure gauges at theupstream <strong>and</strong> downstream of the valve.8.29.1.5 Adequate transportation support should be provided on the valve as an integralpart of the valve.8.29.1.6 Internal: Closing Disc is mounted on 'Central Rod' cladded with Stainless Steel(SS as per AISI304) for the adequate length so that the disc moves on thecladded portion. Bush of the disc should be lined securely with Brass sleeve(minimum 3 mm thick) for smooth sliding of the disc.8.29.1.7 Disc is held in closed position by a adequate number of 'Stainless SteelSprings' (SS as per AISI304). The anti-rotation guides should be provided onthe edge of 'Central Disc' with minimum resistance to flow <strong>and</strong> minimumpossibility to lock during sliding of the disc. The 'Anti Rotation Guide' should becladded with Stainless Steel Strip (SS as per AISI304) <strong>and</strong> 'Guide Fork' linedwith brass liners. The valve should be provided with a 'Stationary CentralDome' to create an annular streamlined passage for smooth flow of water.8.29.1.8 Painting: 2 (Two) coats of Coal tar Epoxy Paint from inside <strong>and</strong> outside.Material of Construction of principal parts:S. No. ITEMS MATERIALa Entry Barrel Shell <strong>and</strong> Coneb Exit Barrel Shell <strong>and</strong> Conec Lap Ringd Guide Domee Central Shaft (S.S. Lined) MS IS:2062 Fe. 410W Af Spring S.S. 304Urban Administration & Development Department Page 101
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