Question 327Steam Plants - 1st Asst/Chief

The correct answer is B) warn the engineer of excessive pressure in the low pressure turbine casing. The sentinel valve is installed on a turbine casing to serve as a safety device. Its primary purpose is to vent excess pressure from the low pressure turbine casing and warn the engineer of any abnormal pressure buildup. This helps prevent damage to the turbine from excessive pressure. The other answer options are incorrect because: A) venting excess steam to the condenser is the role of the safety valve, not the sentinel valve; C) relieving excess pressure to extraction points is not the purpose of the sentinel valve; and D) warning of backflow from the exhaust trunk is not the function of the sentinel valve.