inspection , repair and replacement of prayon filter trays and channels in pa plant , fact cd . , inspection , repair and replacement of prayon filter trays and channels in pa plant , fact cd . , fabrication of hollow shafts of prayon filter trays : collection of required materials and consumables from store . hollow shafts shall be fabricated out of salvaged 200 nb/ sch 160 200 nb pipe/sch 160 ss 316l pipe and end flange out of 25 mm ms plate . transport the fabricated shafts and flanges to workshop for machining and collect them back after machining and transport to work site as per instructions from engineer in charge . , encasing of prayon filter shaft ( filter hose side ) :make required arrangements for the work . remove the existing ms encasing on the hv9 shaft by grinding . fabricate new encasing out of 6mm ms plate by rolling to required profile . encase the shaft area with new encasing in two halves . full weld the encasing on all joint areas . suit the bearing on the bearing area by proper grinding . inspect the flange for any repair . damaged flange areas shall be welded and ground as per instructions . , repair works in spare filter trays . shift and transport the spare filter tray to earmarked area . clean thoroughly the spare filter tray . position the filter tray properly and suitably . leak test the tray by filling water . all arrangements for leak testing including fabrication and providing end dummies shall be done by the contractor . inspect for leaks . also inspect the trays for any surface cracks . collect the required materials for repair from store and transport to work site . repair the leaked and cracked areas by proper grinding the crack/leak area and repair welding with suitable electrode . suitable pad plate is to be provided as per instructions . the welding area shall be dp tested and inspected by engineer in charge . after the repair welding is successfully completed , leak test the tray again . once the leak test is successful drain the water and transport the tray to earmarked storage area as per instructions from engineer in charge , the tray has to be neatly and safely stacked . the leak test for the trays has to be carried out as many number of times till the test results to no leak . all arrangements for leak test will be under contractors scope . , replacement of filter tray end hollow shaft ( cell control lever side ) :clean thoroughly the filter tray . shift and transport the filter tray to the earmarked area . assemble the filter tray on the fixture and perfectly . provide steady pins for firmness . grind the cladding on the shaft . dismantle / cut the existing end shaft . prepare the edges with proper grinding . assemble new shaft , properly align the shaft with the filter tray . full weld the shaft with the tray using suitable electrode . properly grind the weld joint and carry out dp test . any flaw detected will have to be reworked . provide stiffeners for the weld joint area with the tray as required . after complete welding and grinding provide an encasing of hv9 material covering the weld joint area and on hollow shaft upto the bearing area , and full weld on the encasing using suitable electrode as per instructions from engineer in charge . once the replacement work is complete , unmount the tray from the fixture and transport the tray to the stacking area as per the instructions from engineer in charge . clear the site and transport the scrap to area earmarked / scrapyard . , fabricate filter support channel :collect the required material from store and transport to work site . take measurement from existing filter support channel , using ms ismc and ms plate as per the instructions from engineer in charge . all joints shall be full welded . pad plates shall be provided at required areas / joints and shall be full welded as per instructions from concerned engineer . all welding areas shall be properly ground to facilitate rubber lining . once the fabrication is complete shift and transport the channels to rubber lining area for rubber lining . after completion of rubber lining transport the support channel to stacking area and safety stack the channels as per instructions . , replacement of prayon filter support channel :transport the spare support channel to prayon filter site . collect the required tools / tackles / consumables from store / work shop . after getting process clearance and positioning of filter trays , cut and dismantle the existing support channel . grind and finish the welding areas on the filter frame . erect the new support channel to the required position . properly position the channel and correct the alignment of the channel with the frame . properly / full weld the joint areas with the channel and filter frame . take trail run and confirm the position of channel is correct with the position of the tray and there is no entangling of filter tray with the channel . any rework arising out of this i . e . , repositioning and re welding of channels etc . shall be done as per instructions from concerned engineer . after successful trial run , clear the site and transport the scrap to area earmarked / scrapyard . , replacement of prayon filter tray :after getting process clearance dismantle the splash guards , cell control lever , filter hose etc . of the tray to be replaced . dismantle the ci bearings of the tray . shift and transport the tray to the repair bay . repair the tray for the damage / cracks etc . set new ci bearings on the filter shafts . ensure the bearings suits the filter shafts ( bearings have only design clearance with shaft ) under the supervision of concerned engineer . shift and transport the repaired / spare tray assembly to the site and erect the filter tray to position . position the ci bearings on the frame and properly tighten the base bolts and cover bolts . mount the control level assembly , filter hose and splash guards etc . take trial run and ensure the tray doesnt entangle with other trays / filter support channel . any rework arising out of this shall be done by the contractor . after successful trial run clear the site and transport the scrap to earmarked area / scrap yard as per instructions .