Question 320Steam Plants - Assistant Engineer

The correct answer is A) introduce a control for maintaining constant steam pressure regardless of boiler load. The standardizing relay is a key component in a pneumatic automatic combustion control system for a boiler. Its primary function is to maintain a constant steam pressure regardless of changes in the boiler load. By monitoring the steam pressure and adjusting the air/fuel ratio accordingly, the standardizing relay ensures that the boiler operates at the desired pressure, even as the load on the boiler fluctuates. The other options are incorrect because they do not accurately describe the function of the standardizing relay. Option B refers to maintaining constant superheated steam temperature, which is a different control parameter. Option C is about controlling the boiler drum water level, which is typically handled by a separate control system. Option D describes a backup for manual control, which is not the primary purpose of the standardizing relay.