tailieunhanh - Liquid Process Piping Episode 12

Tham khảo tài liệu 'liquid process piping episode 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | EM 1110-1-4008 5 May 99 Step 4. A standard package anode will be used so this type of anode is reviewed to determine how many anodes are required to satisfy the current. The weight of a standard packaged magnesium anode is kg see TM 5-811-7 Table C-4 . The current output to ground is calculated for the anode see TM 5-811-7 eqn. C-2 . i f P T thrust generated N Do outer diameter of pipe mm P design pressure MPa angle of bend degree For the 90 bends -T - . I 50 mm I 2 . 90 I T90 2 I I MPa sin -y 694 N where C 120 000 for a well coated structure see TM 5- 811-7 f see TM 5-811-7 Table C-4 y see TM 5-811-7 Table C-5 P average soil resistivity 4 500 -cm i Cfy 120 000 .A ma P 4 500 cm For the 45 bends 50 mm I 2 _ . I 45 50 2 I MPa sin -y- 376 N Step 5. The number of anodes required is determined see TM 5-811-7 eqn. C-3 . I ma 0 49 . r s i ma The area of the thrust block is calculated by see TI 81403 equation C-2 ATB fs a The kg anode satisfies the current output requirements. Smaller packages anodes are not readily available. THRUST BLOCKS see TI 814-03 Water Distribution for guidance Thrust blocks are required at the 90 and 45 bends. Concrete thrust blocks will be used so the area of the thrust block will be determined. Because the pipes are already cathodically protected additional protection or insulation between the concrete and the pipe is not required. The thrust at each bend is calculated first see TI 814-03 eqn. C-1 . DA 2 . 2 P sin I 2 T 2 where ATB area of thrust block mm2 T thrust generated N a safe soil bearing value MPa assume MPa fs safety factor typically For the 90 bends 694 N 2 A 51 mm 90TB MPa For the 45 bends Aon 376 N 28 mm2 90TB MPa where C-32 i. Line XXX-PYS-101 Chemical Feed from Bulk Polymer to Polymer Day Tank Referencing Sketch C-10 Polymer demand m3 day therefore assuming a 15 minute fill the maximum flow rate Q x 10-2 m3 min x 10-4 m3 s Existing .