CoC Oral Exam Preparation (Part – 17): Boiler Safety Valve

Boiler Safety Valves protect the boiler from over pressurisation. As per the requirements, at least two safety valves should be fitted to the boiler and both are mounted on a common manifold with a single connection to the boiler. Boiler with super heater, normally three safety valves are fitted; two to the boiler drum and one to the superheater. The superheater must be set to lift first to ensure a flow of steam through the superheater.

Improved High Lift Boiler Safety Valve:


Fig: Improved Highlift Boiler Safety Valve

The sketch shown is improve high lift safety valve . The are usually mounted 2 Nos. on a single chest. Valve , seat , spindle , compression screw and bush are made of non-corroded metal and valve chest is made of cast steel.
This valve improve than other type as because:

  • Using wingless valve to improve steam flow
  • Floating cylinder arrangement can prevent piston seizure.

Read more