Lesson 4 - Steam Technology
This lesson takes a closer look at steam technology. It explores the generation of steam in boilers, as well as the distribution system and its components. It also considers the legal requirements associated with steam technology.
Point of Reflection – Reconvene
Welcome back. So, what were your thoughts?
Boiler pressure control should never allow the boiler pressure to go beyond the rating for the boiler. Normally, the pressure is controlled by controlling the fuel supply. A pressure switch can also be used to shut off the fuel supply if this value is reached. Lastly, a mechanical safety feature in the form of a pressure relief valve should be fitted to the boiler. (We will cover pressure relief valves later on in the lesson.)
The boiler water level should also be carefully controlled to ensure that the tubes are covered before the burner is allowed to start. Level control is also required to ensure that the water level is never too high, which in turn should thus avoid water carryover to the steam network. The water pump is controlled by a level transmitter. Typically, there are two independent level switches that will shut the burner off if a low level is detected. A high-level switch can also shut off the water pump if a high level is detected.
Another potentially dangerous situation occurs if the flame goes out. If the fuel continues to be pumped into the boiler, this could result in an explosion when it is ignited. Thus a flame detection system shuts a valve on the fuel supply to the boiler if a flame is not detected.
Before we move on to steam distribution, we need to discuss one more critical topic related to generation – water. We cannot make steam without water!