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Reg. 307 B, Reg. 308, Reg. 309

Torsion Bars

 
Torsion bars shall be manufactured from steel which shall have a yield point of not less than 141 kg./mm² (90 tons/in2.).

Note.-Special steels developed by individual Manufacturers may be accepted by the Chief Inspector of Boilers at their discretion.


Reg. 308

Dimensions

For ordinary lift valves, the compression or extension of safety valve springs required to load the valves to the set pressure shall not be less than one quarter of the diameter of the valve due consideration being given in the case of spring loaded lever safety valves to the ratio of leverage. The proportion of unloaded length to external diameter of the spring shall not exceed 4:1.

These requirements do not apply to full lift and high lift safety valves.



Reg. 309

Determination of Working Pressure

1. The maximum working pressure to be allowed for steel springs of round, square or rectangular section shall be determined from the following formulae:-

For Springs in Extension.

(a) Round section: -

W.P.= 10,000 p Eqn. (80)
DACK

(b) Square section: -

W.P.= 33,333 d³ Eqn. (81)
DACK


(c) Rectangular section: -

W.P.= 160,000 B² H² Eqn. (82)
DACK (3B+1.8H)

where all dimensions in inches

For Springs in Compression.- The working pressure calculated by the above equation may be increased by 25 per cent.
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Message from Chairman of Central Boilers Board About Central Boiler Board History of Indian Boiler Regulations Foreword Contents Chapter Wise Contents Regulation Wise List of Amendments
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