Essay Example on Postcolonial Literature

Anode marking Cleaning the cavity by shovel Placing new anode Covering of anode New anode thus set starts drawing current after 2-3 hours. To check if new anode is set properly, it should withdraw current within the range of 0. NV to 1. 5 NV after 16 hours. Defects in anode change: I) Low set anodes- In this case, anode draws higher current. It can result in clad failure and block drop and hence disturb the metal stability.

The anode set Like this will draw less current.

Consequently, the neighboring anodes will draw high current causing a voltage shake. Improper swiveling- This leaves coke and big crust pieces Jutting out in the cavity forming mushrooms and spikes which will move the metal in the pot ,resulting in voltage shake. Improper Anode Covering- This causes anode burning and drop outs.The dally production of metal In the pot room Is 2-2. 4 tons approximately.

I Norte, tenure Is a need to nave a magnetic Ana tamale Dalliance, metal pad stability and to prevent extra heat loss due to high metal level.

For this purpose, tapping is performed using a 16 ton capacity nonmagnetic hook which maintains an optimum bath level limiting the cooling tendency of pot. 16 MAT Tapping trolley Firstly, the pouring spout is closed with an asbestos ring. The tapping hose pipe goes into the venture. The tapping hole is made bigger or skimming is done to scoop out coke or lose carbon dust using a preheated carbon scoop.

Around 3 ladles, again preheated to avoid explosion with moisture, are used with a tare weight of not more than 8000 keg.

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The siphon of the ladle is placed into the tapping hole and the air valve is opened to start the tapping operation. The final weight of the ladle must not exceed the desired weight by more than 20 kegs. After tapping; the ladle is placed on Mats for transport. A pot controller keeps a check on the tapping process based on he voltage increasing trend. If the voltage detected is higher than 80 NV, the primary anode is lowered automatically for about 0. 8 seconds.

This helps in maintaining the anode cathode distance constant, when metal level falls during tapping. Further if anode effect occurs, tapping is put to a halt till the termination of anode effect. If the voltage deviation between expected voltage and the voltage detected in continuous 3 min after aluminum tapping starts is less than numb or total time of anode lowering is less than cosec, automatic aluminum tapping control exit function is activated. The final metal tapping amount depends on pot temperature, metal height, bath height, and Creosote ratio and noise level within the pot.

Other factors controlling the tapping amount are voltage shake, anode effects and other abnormalities. As already mentioned, the anode beam gets consumed eventually and has a total traveling distance of only 40 SMS, it needs to be raised to maintain a constant anode and cathode distance of 4. 5 SMS. Beam raising employs two auxiliary hooks of 16 tons capacity each for carrying the beam raising Gig. All through this, a hose reel coming out of APT gives a compressed IR supply to the beam raising assembly for maintaining a recommended pressure of 6 bars.

Each anode rod is inserted into the green legs of Gig frame and the hooks are left loose so that whole frame rests on superstructure of pot . A wrench is lowered until the tool is completely on the spindle of the anode clamp . So now, the clamps are loosened and there is a horizontal beam raising ensuring pot voltage does not exceed 200 NV. When the beam rises to the required point, all the clamps are tightened, anode rods are released, Gig frame moves to a clear position above the pot ND the same operation goes on in next half of the pot.