The use of threaded holes in pressure parts in centrifugal pumps pumps

The use of threaded holes in pressure parts shall be minimised. To prevent leakage in pressure sections of casings, metal, equal in thickness to at least half the nominal bolt or stud diameter, plus the allowance for corrosion, shall be left around and below the bottom of drilled and threaded holes.

a) Internal bolting shall be of a material fully resistant to corrosive attack by the pumped liquid.

b) Studs shall be supplied on all main casing joints unless cap screws are specifically approved by the purchaser.