Q. What is meant by triple expansion engine?
A. A triple expansion engine has three cylinders using the same steam expansively in each one.
Q. What is the clearance of an engine as the term is applied at the present time?
A. Clearance is the space between the cylinder head and the piston head with the ports included.
Q. What is the principal which distinguishes a non-condensing from a condensing engine?
A. Where no condenser is used, and the exhaust steam is open to the atmosphere, it is a non-condensing engine.
A. To form a vacuum and thus remove the atmospheric and back pressure that would otherwise be on the piston, thereby getting more useful work out of the steam.
A. By the steam used being constantly condensed by the cold water or cold tubes, and the air pump constantly clearing the condenser.
Q. Why does condensing the used steam form a vacuum?
A. Because a cubic foot of steam at atmospheric pressure shrinks into about one cubic inch of water.
Q. What is a condenser as applied to an engine?
A. The condenser is that part of an engine into which the exhaust steam enters and is condensed.
Q. About how much gain is there by using the condenser?
A. Seventeen to twenty-five per cent. where cost of water is not figured.
Q. What do you understand by the use of steam expansively?
A. Where steam admitted at a certain pressure is cut off and allowed to expand to a lower pressure.
Q. How many inches of vacuum gives the best result in a condensing engine?
Q. What is meant by a horizontal compound tandem engine?
A. One cylinder being back of the other with two pistons on the same rod.
A. Outside lap is that portion of the valve which extends beyond the ports when valve is placed on the center of its travel; inside lap is that portion of valve which projects over the ports on inside or toward the middle of the valve.
A. It gives expansion to the steam in the cylinder.
A. The point where the center of shaft, center of wrist-pin and center of piston rod are in the same straight line.
Q. From what cause do belts have power to drive shafting?
A. Before starting it and as often while running as is necessary.
Q. What is the tensile strength of American boiler iron?
A. 40,000 to 60,000 pounds per square inch.