146
THE HONGKONG GOVERNMENT GAZETTE, MARCH 11, 1910.
224.
The pressure of the steam in water-tube boilers is sometimes greater than at the engines. Why is this, and what percentage above the engine pressure does it amount to? How is this difference of pressure maintained ?
225.
Describe any automatic method of feeding water-tube boilers. Of what material are the tubes made?
226.
Describe the construction of any steam turbine you are acquainted with, which is used on board ship. How is the expansion of steam effected? How many propeller shafts are employed, and how many propellers?
227.
Is the same power in a steam turbine available to go astern as to go
228.
Of what material are the propellers made in a steam turbine ?
220.
ahead?
How many pounds of coal per indicated horse-power pe: hour are burnt with this type of engine? Name the type of boiler in use?
230.
Describe one of the several classes of refrigerating machinery in use on board s-ip. Several types exist, one being more economical than the rest. Which is it?
231.
Describe the defects to which the selected type is subject.
232.
How are the defects overcome?
Name the parts?
How frequently are the parts opened out for examination ?
233.
How frequently are the condensers of refrigerating plants opened for examination ? How frequently are the coils tested by hydraulic pressure? On which side of the coil is corrosion most commonly found? Why should this be so?
234.
Where ammonia is used in refrigerating machinery, should the machinery by preference be isolated? Why? In reply, give what information you possess bearing on the matter, naming the ships for purposes of identification.
235.
Explain how the ammonia is removed from the tubes in which it is supplied, and how passed into the refrigerating machine.
236.
What objection is there to the presence of water in the ammonia?
237.
Describe the ammonia process of refrigeration.
238.
Of what material are the parts made which are in contact with the ammonia?
239.
Are escape-valves fitted to the compressors of ammonia machines?
240.
What is the maximum pressure found in the compressors of ammonia machines ?
241.
What kind of pressure and other gauges are used in ammonia machines?
242.
Explain how carbonic acid is removed from the tubes in which it is supplied, and how passed into the refrigerating machine.
243.
What objection is there to the presence of water in the carbonic acid?