THE HONGKONG GOVERNMENT GAZETTE, MARCH 11, 1910.
138.
141
In the construction of smoke-box doors and of dry uptakes, what provision is made to lessen the amount of radiation ?
139.
How can the formation of black smoke be prevented? Describe smoke preventing apparatus.
140.
What is meant by "circulation" in a boiler, and what are the results of defective
circulation?
141.
What means are sometimes adopted to improve the circulation in a boiler?
142.
By what arrangement is the circulation promoted in a "hay stack" boiler?
143.
Describe a ship's side air-pump discharge valve, in what respects does it sometimes differ from a common stop valve, and what attention does it require ?
141.
What is the construction of a feed escape valve, to what is its discharge connected, and how is its loading regulated? Where should the escaping water flow?
145.
When there is no feed escape valve what is the arrangement of the feed valves or cocks?
146.
What is the measure of a horse-power? How is indicated horse-power ascertained ?
147.
Has "nominal horse-power" a fixed meaning? What is the use of this expression? What is generally taken as the measure of one horse-power nominal?
148.
What is "back pressure in a cylinder? About how much is it in each of the cylinders in your last steamer? Is excessive cushioning ever a trouble under certain condi- tions in modern engines? Say when and why and in which cylinder this occurs?
What is meant by "speed of piston"? modern marine engines?
149.
About how much is the speed of piston in
150.
atmospheric pressure"? What is its average amount? What instrument
What is ( tells this amount?
""
What is "gross pressure" or
by the steam gauge ?
151.
"absolute pressure"?
What pressure is it that is shown
152.
})
What is meant by "cutting off steam? How is it done? What part of the valve regulates the cut off?
153.
What is a piston slide valve? Describe its construction. Why are such frequently employed in place of the common slide valve? Have they any disadvantages compared with a common slide valve? If so, name them.
154.
What fixes the time of closing the exhaust? After the exhaust is closed and before the port opens for steam, what becomes of the steam that is in the cylinder?
155.
What is the "lead" of the valve? What is its object? About what amount is it?
""
136.
What is the cover or "lap" of the valve? What is its object? About what proportion of the stroke of the valve is it made ?