Tubes pass through holes in the front and rear tube sheets and are expanded tight, then beaded or seal-welded. The flat sheets are held against pressure by the tubes and by stays. The rear sheet sees the hottest gas, so scale buildup on its water side quickly overheats it, leading to leaking tube ends, cracked ligaments between holes, and expensive retubing.
Weeping at four tube ends on the rear tube sheet, we'll re-roll them Saturday and hydro it.
Leaks at the rear tube sheet after a hard start are a classic sign of thermal shock or scale under the tube ends.
Also heard as
- tubesheet
- tube plate
Related terms
Firetube boiler
A boiler in which hot combustion gases run through tubes that are surrounded by the water being heated.
Scale
A hard mineral crust that forms on boiler heat transfer surfaces from calcium, magnesium and silica in the water.
Punch the tubes
To clean soot from firetube boiler tubes by running a brush on a long rod through each one.
Fireside
The surfaces of a boiler exposed to flame and combustion gases, as opposed to the waterside surfaces in contact with water.