How Water Tube Type Steam Boilers Work
One of the latest advances in steam boiler technology is the use of water tube boilers. This type of boiler is distinct from conventional fire tube boilers. Water tube boilers are more efficient than fire tube boilers, generating more steam but using less fuel. They are also much safer than fire tube boilers and easier to manage when it comes to routine inspections and maintenance. So how exactly do these water tube boilers operate?
How does it work?
It starts with the burner. When fuel is burned inside the furnace it creates hot gas that flows throughout the boiler. In some cases, the gas will hit the back wall of the boiler and then bounce back toward the other end of the boiler. This helps to create even more heat inside the boiler, which can help reduce the amount of fuel needed to generate heat at optimal levels.
While this hot gas is moving throughout the boiler, it heats up the water inside a series of tubes that sit in the middle of the boiler. These water tubes are shaped like a rectangle and roughly the length of the boiler itself. The tubes are also completely sealed and can withstand a great deal of pressure so that no water can leak out and no fire or gas can penetrate the inside of the tube. Essentially, the fire and gas produced by the burner hover around the water tubes, heating them and the water inside them externally.
This is a notable difference from fire tube boilers, in which the water that’s being used to create steam will surround the heat source. With water tube boilers, the heat source is dispersed throughout the boiler and surrounds the water tubes, which is not only more efficient but also requires less water. The water is also able to move and circulate throughout the tubes, which can put less stress on the boiler, a feature not seen in fire tube boilers.
The water that has been heated inside the tubes rises to the top of the boiler into the steam drum. Sitting at the bottom of the steam drum is boiling water that continues to be heated by the fire and gas created by the burner. This boiling water ultimately becomes steam that can then be released by the boiler to be used for heating and other purposes.
The process typically takes only a few minutes, creating usable steam at a much higher rate than fire tube boilers, which can take an extended period of time to reach peak production levels.
Water-tube boilers also have a downcomer tube that connects the steam drum to the feedwater drum. If the steam cools and condenses back into water droplets, that water can drain from the steam drum to the feedwater drum via the downcomer tube. This allows that water to re-enter the boiler’s water supply, go back into the tubes, and once again be turned into useful steam. Again, this helps to reduce the amount of water needed inside the boiler.
The entire process is not only done quicker than with traditional boilers but it can also be done in a much smaller area. As a result, water tube boilers have a smaller footprint than conventional fire tube boilers, making room for more boilers than can further enhance efficiency.
Contact Miura today to learn more about water tube type boilers.