Reg. 283, Reg. 284, Reg. 285, Reg. 286
METHOD OF CONSTRUCTION
||All castings shall
be smooth, sound and free from flaws, cracks or other
injurious defects. Variations in thickness at any part
shall be gradual and substantial fillets shall be provided.
||The body of a boiler
mounting shall be connected to the boiler flange by a
strong and stiff neck. In no case shall the thickness
of the neck of bronze mounting be less than 3/16 inch
for sizes up to and including 3/4 inch bore.
Packing of Cocks
| The bodies of all cocks except
those for pressure gauges shall be packed with asbestos
or other heat resisting material and shall be or substantial
design, those over one inch bore shall have special provision,
other than the gland for securing the plug.
Water gauge column cocks may be either asbestos packed
or solid plug type.
Covers and Spindles
||Valves of 1½
inch bore and over directly connected to boilers, and
other valves of 2½ inch bore and over where fitted
with a cover shall have such cover secured by bolts or
studs and the screwed portion of the spindle shall be
outside the stuffing box. All valves for superheated steam
shall be fitted with an external screwed spindle.
|| Where the covers
of valves are secured by studs, the studs shall be screwed
into the body with full thread for a length of at least
one diameter. The stud holes shall not penetrate into
the pressure space of any casting.
|| Valves with screwed
covers shall be fitted with suitable locking device to
prevent rotation of the cover.
Direction of Operation
|Valves shall be clearly marked
to indicate the direction of flow. Valves directly connected
to boilers shall be fitted with indicators to show clearly
whether the valve is closed or open and all valves shall
open by anti-clockwise rotation.