2.8.14 Fittings
All fly ash conveying line fittings i.e. bends, elbows, laterals and spool pieces shall be alloy cast iron or basalt lined fittings. These shall be either flanged or plain end fittings.
All the fittings (bends, elbows/laterals spool pieces etc.) in the conveying lines shall be as per good Engg. practice and of large radius construction (min. 5D).
Alloy C.I or basalt lined (as the case may be) spool pieces of minimum 1.5 m length shall be provided at the discharge of every bend or lateral, which shall be directly welded to the bends/laterals or joined with either a flanged connection or a sleeve coupling with the bends/elbows.
Material of construction and other design parameters of the piping are as follows:
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Pipe size (I.D.) |
As required. |
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Type of Pipes |
Class-D cast iron pipes conforming to IS:1536 or BS:1211. |
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Type of Joints |
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Pipe to Pipe, Pipe to Fitting, Pipe to valve & valve to Fitting, Fitting to Fitting, |
Flanged/sleeve coupling |
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Fittings (Bends, elbows laterals and spool piece etc.), |
Ni-hard/chrome-alloy cast iron or equivalent. Minimum hardness 400 BHN. and wear back thickness minimum 20 mm. or |
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20 MM thk. Cast basalt lined MS fittings (MS sheet of 6 mm thickness) |
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Basalt Lining |
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Hardness |
8 mhos (Min.) |
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Bending strength |
300 Kg/cm2 (Min.) |
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Compressive strength |
4500 Kg/cm2 (Min.) |
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Density |
2.8 – 2.9 Kg/cm3 |
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Sleeve Couplings |
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Material of Construction |
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(a) Sleeve |
9.0 mm thick carbon steel ASTM-36/BS EN 10025: :1993 Grade S:275/355 or CI FG 260:IS:210 |
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(b) Flanges/End rings |
Carbon steel to ASTM –A-108/Cast IRON FG-260, IS:210 steel and rings shall be formed from hot rolled sect welds. |
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(c) Gasket |
: To suit ash temperature |
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Material Nitrile (NBR) BS:2494 Grade G/Neoprene
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Nuts & Bolts |
Hot dip galvanised as per IS:4759. Bolts, nuts and washer should be of similar material to those used for coupling housing/sleeves to minimise the possibility of galvanic corrosion. |
Spec Ash Handling Plant 