Question { GNFC, 20528 }

why cenrifugal pump casing is called involute casing.

Answer

Yes it does look like an involute that's why it is called involute casing. The main reason behind this is that as the fluid moves through the casing some amount passes through the runner so, Q decreases and thus the velocity tends to decrease. To keep the velocity constant the cross sectional area is decreased so as to make up for the loss of velocity.

Question { Ingersoll Rand, 3566 }

What is difference between cast iron and grey cast iron.

Answer

Cast iron refers to a class of iron-carbon alloys in which the percentage of carbon is greater than 2%. While Grey cast iron is a class of cast iron which has Graphite flakes. The grey in grey cast iron comes from the grey fracture it forms while breaking.