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.

[Ill.u.s.tration]

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.

=AIR BRAKE QUESTIONS=

COMPRESSOR GOVERNOR

1. Q. When steam is first turned on, what must it pa.s.s through before entering the compressor?

A. The compressor governor.

2. Q. What does Fig. 1 represent?

A. This shows a sectional view of the SF compressor governor in open position.

3. Q. What is the duty of the compressor governor?

A. To automatically regulate the main reservoir pressure by controlling the steam to the compressor.

4. Q. How are the regulating portions of the governor designated?

A. The one having two pipe connections and a light regulating spring is known as the excess pressure head; the other, with a single pipe connection and heavy regulating spring, as the maximum pressure head.

5. Q. When does the excess pressure head control the flow of steam to the compressor?

A. When the automatic brake valve is in any one of its first three positions; namely, release, running and holding positions.

6. Q. With the automatic brake valve in release, running or holding position, what pressure is in chamber "f" above the diaphragm? In chamber "d" below the diaphragm?

[Ill.u.s.tration: Fig. 1. The SF-4 Compressor Governor.

Connections: FVP, Feed Valve Pipe. ABV, Automatic Brake Valve.

MR, Main Reservoir. B, From Boiler. P, To Air Pump.]

A. Air, at feed valve pipe pressure, enters at the connection marked "FVP" and flows to chamber "f" above the diaphragm; this pressure acts in conjunction with the regulating spring 27 in creating the total pressure on the diaphragm. Air at main reservoir pressure flows through the automatic brake valve to the connection marked "ABV" to chamber "d"

under the diaphragm.

7. Q. At what pressure is the regulating spring in the excess pressure head adjusted?