Modern Machine-Shop Practice Part 269

What are the known causes of priming? Why is priming wasteful? Can blowing off at the safety valve cause priming? What are other causes of priming? How can priming be detected? What would you do to stop priming?

What would you do to prevent priming? What parts of the engine would you attend to if the boiler primes? II. 370.

=Low water.=--What would you do if the water got dangerously low in the boiler? In such a case how would you regulate the dampers? What do you consider dangerously low? What is blowing down a boiler? II. 370.

=Cleaning a boiler.=--How often would you clean a boiler? II. 371.

=Water falling.=--What would you suppose was going wrong if the pump was kept going and the water still fell in the boiler? II. 370.

=Empty pump.=--What causes a pump to fail? II. 370.

=Blowing down.=--How much would you blow down a boiler? How low should the pressure get before the water is let out? What would be the result if the boiler was blown off under a high pressure? What would you do after the water is all out of the boiler? II. 371.

=Special examination.=--What parts would you pay special attention to in examining the boiler after cleaning it? II. 371.

=Hammer test.=--What does the "hammer test" consist of? II. 371.

=Washing and scaling.=--What determines the periods at which a boiler should be washed out and scaled? II. 371.

=Regulating dampers.=--How would you regulate the dampers when letting the fire out? II. 371.

=Naming the parts.=--Name all the parts of a simple or plain D slide-valve engine, beginning with the cylinder. II. 372.

=Dividing the parts.=--Into what three divisions may the parts of a plain slide-valve engine be divided? II. 372.

=Defining clearance.=--What is the meaning of the word "clearance" as applied to an engine cylinder? II. 372.

=Finding equal clearance.=--How would you proceed to find if the clearance in the cylinder was equal at each end? II. 372, 404.

=Parts of valve motion.=--What parts const.i.tute the valve motion or valve gear? II. 372.

=The driving parts.=--What parts const.i.tute the driving or power-transmitting mechanism? II. 372.

=Lubricating attachments.=--Name the attachments used upon an engine cylinder to lubricate the piston and valves. II. 373.

=Pet c.o.c.k.=--What is the difference between a cylinder pet c.o.c.k and a cylinder relief valve? II. 373.

=Relief valves.=--What are cylinder relief valves used for? II. 373.

=Quick steam admission.=--Which gives the quickest steam admission, a long and narrow or a wide and short steam port, both having the same area? II. 373.

=Placing the piston-ring split.=--At what part of the cylinder bore should the split of a piston ring be placed? II. 374.

=Fitting a piston ring.=--How tight should a piston ring fit to the cylinder bore? II. 374.

=Testing steam tightness.=--How would you test the steam tightness of a piston? II. 374.

=Jacketed.=--What is a jacketed cylinder? II. 374.

=Valve gear.=--What is a releasing valve gear? What is a positive valve gear? II. 374.

=Packing a stuffing box.=--About how full of packing would you fill a stuffing box for a piston gland? II. 375.

=Connecting rods.=--What are the two princ.i.p.al kinds of connecting rods?

What is meant by the angularity of a connecting rod? II. 375.

=Oiling guide bars.=--Which guide-bar is the most difficult to oil, the top or the bottom one? II. 375.

=Effect of angularity.=--What effect does the angularity of the connecting rod have on the piston motion? Is this effect increased or diminished by shortening the connecting rod? II. 375.

=Crank at full power.=--When the crank is at its point of full power, is the piston in the middle of the cylinder? Is it nearer to the crank-end or the head-end of the cylinder? II. 375.

=Piston motion irregular.=--What causes the piston to have irregular motion? II. 375.

=Live steam period.=--What const.i.tutes the live steam period of a position? II. 376.

=Cut-off.=--What is the point of cut-off? II. 375.--What is a separate cut-off valve, and what event does it control in the supply of the steam to the cylinder? How is the point of cut-off varied when a cut-off valve is used? II. 378.

=Working expansively.=--What causes the steam to be worked expansively in an engine cylinder? II. 402.

=Follower.=--What is a piston follower? II. 374.

=Valve lead.=--What is the lead of valve? II. 376.

=Valve lap.=--What is the lap of a valve? II. 376.

=Admission.=--What is the point of admission? II. 376.

=Cushioning.=--At what point in the valve travel does cushioning begin?

II. 376.

=Release and compression.=--What are the points of release and of compression? II. 376.

=Double-ported valve.=--What is a double-ported valve? II. 377.

=Valves.=--What is a griddle valve? What is a balanced valve? II.

377.--What is a piston valve? II. 378.

=Slide and piston valves.=--Is there any difference between the action of a plain slide valve and a piston valve if both have the same amount of lap, lead, and travel? II. 378.

=Cut-off diagram.=--Make a diagram to give the dimensions of a slide valve, to cut off at 3/4 stroke, the valve travel being 4 inches. II.

380.

=Reversing an engine.=--What is the ordinary means provided for reversing an engine? II. 383.

=Full gear.=--What is the meaning of the term full gear, with regard to a link motion? II. 383.

=Third use Of link motion.=--What does a link motion accomplish besides enabling the engine to run in either direction? II. 383.

=Slide valve for link motion.=--What are the two operations to be performed in setting the slide valve of an engine having a link motion?