20.  Q. How would you reverse conveyor screw in tank?

A. Lower handle 10 on operation rod on boiler head to bottom position.  Move screw conveyor, reverse lever 12 back to rear or reverse position, raise handle 10 on operating rod to center position.

21.  Q. How would you stop conveyor screw in tank?

A. Place conveyor reversing lever 12 in center position.

22.  Q. How would you reverse right or left elevator screw?

A. Raise elevator pawl shifter 26 on top of the vertical shaft to upper position.

23.  Q. How would you stop right or left elevator screw?

A. Raise elevator pawl shifter 26 on top of the elevator to middle position.

24.  Q. How would you locate clogs in case the stoker stalls?

A. First, shut off pressure to stoker engine cylinder by closing valve 6.  Second, move operating valve lever 10 to its lowest position.  Third, place tender conveyor reverse lever 12 in center.  Fourth, place right elevator pawl shifter 26 in neutral position.  Fifth, raise operating valve lever 10 to center position.  Sixth, open valve 6 sufficiently to run left elevator to ascertain if it operates freely.  Cut in right elevator by lowering pawl shifter 26, and if stoker stops, the obstruction is in the right elevator.  If it continues to operate, then the obstruction is in the tank conveyor.

25.  Q. How would you remove clogs?

A. Clogs in upright elevators usually occur at the bottom.  Raise the door in the engine deck and remove the obstruction if in the elevator, reverse the elevator screw forcing the obstruction back down in transfer hopper.  It may be a small mine spike lodged above this point, and by removing the nut at top of elevator casing and removing the door the obstruction can be easily removed.

26.  Q. If the clog is in the tank conveyor, how would it be removed?

A. The clog will usually be found in the crushing zone.  Reverse the tank conveyor screw, forcing the obstruction back, when it can be removed from the trough.

27.  Q. How far should the conveyor screw be run backwards?

A. Not more than three revolutions.

[Illustration]

Parts of duplex locomotive stoker 1.  Conveyor Trough. 2.  Conveyor Screw. 3.  Angle Ring. 4.  Crusher. 5.  Operating Head. 6.  Driving Engine Cylinder. 7.  Reverse Valve. 8.  Piston Rod. 9.  Transfer Hopper. 10.  Left Elevator Casing. 11.  Left Elevator Screw. 12.  End of Elevator Screw Shaft. 13.  Elevator Pawl Shifter. 14.  Elevator Pawl Casing. 15.  Distributors. 16.  Left Distributor Elbow. 17.  Right Distributor Elbow. 18.  Dividing Rib. 19.  Right Elevator Casing. 20.  Oil Box. 21.  Conveyor Reverse Lever. 22.  Conveyor Oil Cups. 23.  Rack Housing. 24.  Rack. 25.  Conveyor Pawl Casing. 26.  Conveyor Screw Flexible Connection Sleeve. 27.  Conveyor Screw Flexible Connection. 28.  Conveyor Slide Support Roller. 29.  Conveyor Slide Support. 30.  Conveyor End Bearing and Gear Case. 31.  Conveyor Screw Gear. 32.  Conveyor Screw Driving Gear.