Gravity casting

Gravity Mold Casting Gravity Pulls It Down... 

Design Applications of Gravity Cast Zinc, International Lead Ziuc Research Organization/Zinc Institute, New York, 1972, 36 pp. 

Traditionally, sodium dichromate dihydrate is mixed with 66° Bh (specific gravity = 1.84) sulfuric acid in a heavy-walled cast-iron or steel reactor. The mixture is heated externally, and the reactor is provided with a sweep agitator. Water is driven off and the hydrous bisulfate melts at about 160°C. As the temperature is slowly increased, the molten bisulfate provides an excellent heat-transfer medium for melting the chromic acid at 197°C without appreciable decomposition. As soon as the chromic acid melts, the agitator is stopped and the mixture separates into a heavy layer of molten chromic acid and a light layer of molten bisulfate. The chromic acid is tapped and flaked on water cooled roUs to produce the customary commercial form. The bisulfate contains dissolved CrO and soluble and insoluble chromic sulfates. Environmental considerations dictate purification and return of the bisulfate to the treating operation. 

GRAVITY DIE CASTING PROCESS CAPABILITY MAP FOR IRON AND COPPER AND ZINC ALLOYS... 

Cast iron 50 pounds per cubic foot—specific gravity 7.21... 

Wrought iron —485 pounds per cubic foot—specific gravity 7.77 Cast iron —450 pounds per cubic foot—specific gravity 7.21... 

The parameters of pipe bore, flow, length of pipe, and specific gravity can be used to determine pressure loss. The calculators are versatile in that they can be used for pressure losses of under 1 mbar and for up to 50 bar. Scales for both cast iron and steel pipe are available for greater accuracy. 

Blowdown sumps should be constructed from brick and/or concrete and the blowdown lines should drain under gravity. Where the blowdown lines enter the sump they should turn to discharge downwards and the bottom of the sump should be protected below this area with a cast iron tray to prevent erosion. The drain or overflow from the pit should be at such a level to produce a weir effect, thus holding water for dilution. 

Gravity die cast ZA alloy test plates and 99.99% pure rolled zinc samples were exposed at a waste water treatment plant in Detroit, Michigan, USA. The results after one year are summarised in Table 4.38 . 

Fatigue strength (5 x 10 cycles) Sand or gravity cast 52 104 172... 

Pressure die cast Impact strength (J) Sand gravity 48 57 20 25 48... 

Never use cast iron fittings or pipe in process situations unless there is only gravity pressure head (or not over 10 psig) or ihe fluid is nonhazardous. One exception is in some concentrated sulfuric acid applications however, extreme caution must be used in the design of the safety of the system area. Never use in pulsing or shock service. 

AVT Barg BD BDHR BF BOF BOOM BOP BS W BSI BTA Btu/lb BW BWR BX CA CANDUR CDI CFH CFR CHA CHF CHZ Cl CIP CMC CMC CMC COC All-Volatile treatment bar (pressure), gravity blowdown blowdown and heat recovery system blast furnace basic oxygen furnace boiler build, own, operate, maintain balance of plant basic sediment and water British Standards Institution benzotriazole British thermal unit(s) per pound boiler water boiling water reactor base-exchange water softener cellulose acetate Canadian deuterium reactor continuous deionization critical heat flux Code of Federal Regulations cyclohexylamine critical heat-flux carbohydrazide cast iron boiler clean-in-place carboxymethylcellulose (sodium) carboxy-methylcellulose critical miscelle concentration cycle of concentration... 

Color, yellow character, hazy glucose (-) ketones (-) specific gravity 1.020 pH 5.0 (+) protein coarse granular casts, 5 to 10/low-powered field white blood cell (WBC) count, 5 to 10/high-powered field red blood cell (RBC) count, 2 to 5/high-powered field no bacteria nitrite (-) blood small osmolality 325 mOsm urinary sodium 77 mEq/L (77 mmol/L) creatinine 63 mg/dL (5569 pmol/L)... 

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