Reg. 287, Reg. 288, Reg. 289
|The valves and spindles shall
be efficiently guided and means shall be provided in every
case to prevent them leaving their guides. The working
parts shall have sufficient clearance to ensure freedom
of movement under all conditions of service.
||Flanges shall be
in accordance with the tables for the appropriate
pressure (Appendix E).
||In the case of safety
valves, the drilling, thickness and bolting of inlet flanges
shall be in accordance with tables for the appropriate
pressure and material and for the diameter of flange adopted.
In the case of outlet flanges the pressure taken shall
be the pressure on the outlet side of the valve.
||For the purpose
of determining particulars of flanges for blow down and
scum pipe fittings, the design pressure of the fittings
shall be assumed to be the working pressure of the boiler.
||All flanges shall
be machined on the face, spot faced, or machined at the
back, and the bolt holes shall be drilled.
|Where separate seats are fitted
they shall be efficiently secured. Means shall be provided
in every case to prevent the valves leaving their guides.