2.8.26 Ash Slurry Sump Isolation Plug Valves, Sump Liners and Agitating Nozzles

2.8.26               Ash Slurry Sump Isolation Plug Valves, Sump Liners and Agitating Nozzles

 

                        The ash slurry sump shall have two(2) isolated compartments in combined ash disposal pump house. Each compartment shall serve two (2) nos. streams of combined ash disposal pumps.  The bottom ash and fly ash slurries shall be led to a common distribu­tion trough at the top of the slurry sumps which will have manually operated plug valves enabling the slurry to flow to the desired compartments (corresponding to the pump steams in operation).

 

                        It shall be possible to operate slurry sump isolation valves from top of sump level. The valve shall be provided with gear operator if effort required to operate the valve exceeds 25 kgf.

 

                        Material of construction for slurry sump isolation valves shall be corrosion and abrasion resistant and shall be of quality most suited to proposed application. Suitable measures to protect the bearings from ash ingress shall be provided.

 

                        Valves shall be suitable for outdoor duty.

 

                        All the slurry distribution troughs and sump compartments shall be provided with abrasion liners in the areas of slurry impingment.

 

                        A layout drawing including cross section of slurry trenches shall be submitted. The Bidder shall furnish the section and dimensions of the trench liners as per the slopes indicated elsewhere in this specification to convey the slurry by gravity to the slurry sump. A free board of min. 100 mm shall be provided for the trench liners.

 

                        Cast iron lining (IS:210, FG 260) for the inner walls of the slurry trench/sump shall be provided by Contractor. The lining should be minimum 20 mm thick, on side walls and 30 mm thick at bottom”.

 

                        Bidder shall provide adequate number of high velocity water jetting/agitating nozzles in the slurry trenches/sumps to avoid setting of ash particles at the bottom of the trenches/sumps. The material of jetting/agitating nozzles shall be anti corrosion tool steel of hardness 500-550 BNH.

 

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