This set of Thermal Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Reciprocating Steam Engine – Parts, Working and Terminology – 1”.
1. The engine cylinder of a reciprocating steam engine is made of _____
a) Cast-iron
b) Chromium
c) Aluminum
d) Speed steel
View Answer
Explanation: In a reciprocating steam engine, the cylinder is made of cast-iron. It is bored out perfectly true. In case of small engines, it is integral with the frame. It is produced by casting.
2. The engine cylinder of a reciprocating steam engine is produced using casting operation. The casting of the cylinder consists of two chamber, namely _____
a) Steam chamber and condensing chamber
b) Cylinder chamber and valve chamber
c) Top chamber and bottom chamber
d) back chamber and front chamber
View Answer
Explanation: The engine cylinder of a reciprocating steam engine is casted, the casting consists of two chambers, cylinder chamber and valve chamber. Steam ports connect the cylinder ends with the steam chest.
3. Which of the following statement about steam ports (of reciprocating steam engines) is FALSE?
a) They connect the engine cylinder with the steam chest
b) The steam ports should have large cross-section
c) Steam reaches the engine cylinder after passing through the steam ports
d) The purpose of steam ports is to throttle the steam as it passes through
View Answer
Explanation: The engine cylinder is connected at its end with the steam chest through steam ports. Steam is supplied to the cylinder through the steam ports. The cross-sectional area of the steam ports should be large, so that it can admit enough steam into the cylinder. If the steam port is not large enough the steam will be throttled or wiredrawn.
4. In an engine cylinder (of a reciprocating steam engine), the end of cylinder through which the piston rod passes is known as _____
a) crank end
b) front end
c) top end
d) cover end
View Answer
Explanation: Crank end or back end or bottom end, is that end of the engine cylinder through which the piston rod passes. Therefore, crank end is the correct answer. The other end of the cylinder is covered fully by a cover and it is known as cover end or front end or top end.
5. Which of the following statement about stuffing box (in a reciprocating steam engine) is TRUE?
a) Stuffing box is the casing which engine assembly is placed
b) Stuffing box guides the crank shaft
c) Stuffing box provides a steam-tight hole for the piston rod to pass through, to prevent steam leakage
d) Stuffing box serves no purpose during engine operation
View Answer
Explanation: Piston rod passes through the crank end of the cylinder, at this end the piston rod must pass through a steam-tight hole, to prevent leakage of steam. Stuffing box does this job. The piston passes through the steam-tight hole in stuffing box, ensuring that no steam is leaked.
6. The name of the non-conducting material covering the engine cylinder, of a reciprocating steam engine, to reduce condensation of the steam is called _____
a) graphite
b) ceramide
c) leading
d) lagging
View Answer
Explanation: As the steam expands, it cools down as tends to condense. To avoid this the steam engine cylinder is steam-jacketed. Covering the cylinder with lagging (a non-conducting material), the steam condensation is further reduced.
7.Steam is admitted into the engine cylinder from a reservoir of steam called as _____
a) Stuffing box
b) Steam chest
c) Eccentric
d) Cross-head
View Answer
Explanation: Steam chest acts as a reservoir of steam and allows the steam into engine cylinder during the admission stroke of the piston. It is closed with a cover called steam chest cover. It is cast integral with the cylinder.
8. What is the function of a piston in a reciprocating steam engine?
a) It converts the pressure energy of the steam to its reciprocating movement
b) It converts its reciprocating energy to pressure energy of the steam
c) It acts a reservoir to store steam
d) It reheats the steam before entering into the steam chest
View Answer
Explanation: The function of the piston in a reciprocating steam engine is to covert the pressure energy to its reciprocating movement. It moves inside the cylinder, end to end. Piston is made of forged steel, cast steel or cast iron.
9. Which of the following statements about the piston rings is FALSE?
a) Piston rings prevent leakage of steam
b) Piston rings reduce the friction between the piston and wall
c) Piston rings are generally made of cast iron
d) Piston rings are fixed to the engine cylinder
View Answer
Explanation: The function of piston rings is to prevent leakage of steam and to reduce the friction between the piston and the wall. They are usually made of cast iron. Piston rings are fixed to the piston and not the engine cylinder.
10. Stuffing box is made of _____
a) Chromium
b) Aluminum
c) Cast iron
d) Cast steel
View Answer
Explanation: Stuffing box is made of cast iron. A stuffing box is used to prevent the leakage of fluid where a sliding or rotating piece passes through a vessel containing fluid at a certain pressure. In case of reciprocating steam engine, it used to prevent the leakage of steam.
11. Cross-head of a reciprocating steam engine is usually made of wrought iron, cast steel or forged steel.
a) True
b) False
View Answer
Explanation: Cross-head connects the outer end of the piston rod to the small end of the connecting rod. It is made of wrought iron, forged steel or cast steel. Cross-heads of small size are usually forged as one with the piston rod.
12. The end of the piston rod is joined to the connecting rod by _____
a) Cross-head
b) D-slide valve
c) Stuffing box
d) Steam chest
View Answer
Explanation: Cross-head slides inside the guide. It connects the piston rod to the connecting rod. It receives the reciprocating motion from the piston rod. In some engines the guide is cast with the frame of the cylinder.
13. Which of the following statements about cross-head of a reciprocating steam engine is FALSE?
a) It connects the piston rod with the connecting rod
b) Piston rod in some engines is joined to the cross-head by screwing
c) In some engines cotter joint is used to join piston rod with the cross-heads
d) Knuckle-joint is used to join cross-head and piston
View Answer
Explanation: The piston rod is either screwed to the cross-head or a cotter joint is used to join the two. In some engines the piston rod is forged to the cross-head end. The reciprocating piston rod and the oscillating connecting rod are joined by the cross-head.
14. What is the function of a connecting rod in a reciprocating steam engine?
a) It converts the circular motion of the crankshaft into the reciprocating motion of the piston rod
b) It converts the reciprocating motion of the crankshaft into reciprocating motion of the piston rod
c) It converts the reciprocating motion of the piston rod and cross-head into circular motion of the crankshaft
d) It converts the circular motion of the piston rod and cross-head into circular motion of the crankshaft
View Answer
Explanation: The connecting rod in a reciprocating steam engine, joined to the piston rod end by cross-head, converts the reciprocating motion of the piston rod and cross-head into circular motion of the crankshaft. Connecting rod performs oscillatory motion.
15. The connecting rod of a reciprocating steam engine is made by casting.
a) True
b) False
View Answer
Explanation: The connecting rod of a reciprocating steam engine is made of steel forging of rectangular, I, H or circular section. one end of the connecting rod is connected to the crank and the other to the cross-head.
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