A. The header is a simple casting, divided by partition walls into
saturated and superheated steam passages. It is located between the dry
pipe and the steam pipes, the same as the nigger head in a saturated
locomotive. The dry pipe is in communication with the saturated steam
passages and the steam pipes with the superheated steam passages and
these are in communication with each other through the superheated
units.
9. Q. Describe the construction of superheater units and their
connection to the header.
A. The units are composed of four seamless steel pipes, connected by
three return bends. Of the four pipes, two are straight and two are bent
upward and connected to the header by means of a clamp and bolt; one end
of the unit is in communication with the saturated steam passage and the
other with the superheated steam passage in the header casting.
10. Q. Trace the flow of steam through the top header fire tube
superheater.
A. When the engine throttle is open, saturated steam passes through the
dry pipe into the saturated steam passage of the header casting. From
this passage it enters one end of the unit, passing backward toward the
fire-box, forward through one of the straight pipes and the front return
bend, backward through the other straight pipe to the back return bend,
and forward through the bent pipe and upward into the superheater steam
passage of the header, from which it enters the steam pipes and is
carried to the steam chest.
11. Q. What should be the position of throttle valve when running a
superheater locomotive?
A. The engine should always be run with as wide open throttle as the
conditions will permit, regulating the steam admission to the cylinders
according to work to be performed.