The difference of pressure between the outside air and the smoke-box gases may be measured by the difference of the water levels in the limbs of a U tube, one limb being in communication with the smokebox, the other with the atmosphere.
dished smokebox door, a rolled steel stovepipe and encased Ramsbottom safety valves.
drumhead smokebox onto the original barrel working at 180 lbs.
Each ejector is fitted with a non-return valve to prevent smokebox gases being drawn back through the ejector exhaust.
No one else had rectangular headboards carried across the center of the smokebox door.