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Second Stage or Advanced Examination.
INSTRUCTIONS.

Read the General Instructions on page 1.

Draw the example shown on Diagram Y. It should be drawn on the side of the paper on which the candidate's number is printed.

Answer briefly any three, but not more than three, of the following questions.

Foolscap paper must not be used for this stage. No credit will be given for any work in this stage on foolscap paper.

Example to be drawn.
Diagram Y.

Valve box and valves of a pump for charging an hydraulic accumulator.

In the diagram a portion of the pump barrel and piston are shown for information, but no part of them is required to be drawn in any of the views.

(p.) Draw the outside elevation of the valve box from the same position of view as that of the sectional elevation shown in the diagram, the pump barrel being supposed to be removed.

(q.) In projection with (p), to the right of it, draw a sectional elevation of the valve box, across the plane of AB, as viewed from the left, showing the valve in place. (r.) Also draw, projected from (p), to the left of it, an end view of the valve box, as seen from the left-hand end. Scale

Do not draw the plan.

Do not draw the elevation in section.

(140.)

Do not draw the valve separated from the valve box, and
Do not draw dotted lines representing hidden parts.

Questions, only three to be answered.

The sketches in answer to these questions should be drawn freehand. (g.) Point out the various ways in which a screwed bolt and nut may yield to the forces to which they are subjected. Calculate the diameter of the screwed end of a piston rod for a cylinder of 20" diameter, the greatest pressure on the piston being assumed to be 80 pounds per square inch. Give dimensioned sketches of the nut.

(h.) Give sketches showing the construction of a block to fit some form of Stephenson's curved link, used in reversing engines, in which the block is so made as to be capable of being adjusted for wear. (20.) (k.) Give sketches showing the construction of a bracket to be secured to a plain cylindrical column, suitable for providing a bearing for a horizontal shaft which carries a vertical load. (20.) (1.) Quote two instances, differing as much as possible from one another in construction, where rollers are used in machines for the purpose of diminishing friction. Give sketches showing the construction in each instance.

(20.) (m.) Give an instance in which some portion of a machine is case-hardened, and sketch the form of the case-hardened portion. Describe how the process of case-hardening is performed, and how the hardened surface is made accurate and smooth.

(20.) (n.) In the pump for charging an hydraulic accumulator shown in diagram Y, trace the course of the water, and describe the action of the valves, during both the out stroke and the in stroke of piston rod. Determine the diameter of the piston rod by the use of which the volume of water delivered by the pump will be the same in each stroke. Explain the purpose of the small sloping holes in the valve box covers. (20.)

Honours Examination.

INSTRUCTIONS.

Read the General Instructions on page 1.

You are permitted to answer only eight of the following questions. The same number of marks is allotted to each question.

The sketches and answers to these questions may be drawn and written on foolscap paper, which may be obtained on application to the superintendents of the examination.

The sketches may be in pencil, and, except in answer to question 54, need not be drawn to scale, but should be neat and in good proportion. The written answers should be in ink, and must adjoin the sketches to which they refer.

NOTE FOR CANDIDATES IN HONOURS. The paper which was formerly worked at home by candidates for Honours in this subject has been discontinued, and an examination at South Kensington substituted for it. This examination will only be open to candidates who answer the present paper sufficiently well to give them a reasonable chance, if the South Kensington papers are well answered, of obtaining a 1st or 2nd class. Honours candidates admissible to the examination at South Kensington will be so informed in due course.

51. Give a general account of the methods and apparatus employed in getting mechanical work done by means of the pressure of high-pressure fluid. Quote a variety of instances, and illustrate with sketches. Point out the advantages due to the form of the working chamber to which the high-pressure fluid is admitted, how a continuous motion is maintained, and any important difference in the construction due to the character of the high-pressure fluid which is used, as, for example, steam, air, or water.

(50.)

N.B-No details relating to valves are required in the answer to this question.

52. The quantity and the pressure of fluid supplied to, or delivered from, a machine are regulated by valves, which are opened and closed in the following five ways:

(1.) Position of valve adjusted by hand at the will of the operator.

(2.) Position of valve altered by automatic mechanism when desired limits of quantity and pressure are about to be exceeded.

(3.) Position of valve continuously altered by automatic mechanism to maintain a regular flow of fluid to and from the machine.

(4.) Position of valve altered by pressure of fluid itself, and regular flow thereby maintained.

(5.) Valve opened by hand of operator to admit fluid, but automatically closed by the consequent movement of the machine.

Enumerate as many distinct instances as you can of the employment of each of the five systems of operating valves above mentioned, and, with the aid of sketches, give detailed information relating to one example of each of three of the systems.

N.B.-Credit for details relating to systems (2), (3), and (5) will be given at twice the rate of that for (1) and (4).

53. Mention as many distinct instances as you can, differing constructively from one another, in which energy, which is transmitted continuously in one direction by means of a rope, belt, or other tension element, is employed to do work in overcoming some kind of resistance. In each case state the means provided for stopping the transmission of the energy, or ceasing the utilization of the energy.

Select any one of the instances you have quoted with which you are most familiar and with the aid of sketches describe the details of the construction.

(50.) 54. The tubes of a boiler, in which the water surrounds the tubes, are spaced 3" from centre to centre, both horizontally and vertically. One-fourth of the number are steel stay-tubes, which should be designed to bear the whole load, without any assistance from the other tubes. The test pressure to which the boiler is subjected is 225 lbs. per square inch. The internal diameter of the tubes is 2", and the thickness of each steel tube-plate is 18". Determine the suitable thicknesses of the tubes, and draw to scale, full-size views showing the attachment of a stay-tube and an ordinary tube to the tube plates at both ends.

16

Give all particulars relating to the construction and fitting of the tubes which are not apparent in the drawings. (50.) 55. Determine the dimensions suitable for the safety-valves and springs, either of a marine boiler, the area of the firegrate of which is 60 square feet, and working pressure of steam 110 lbs. per square inch; or those for the boiler of an English express locomotive engine.

Give sketches showing the construction of the safety valves and the fittings belonging thereto for one of the boilers.

(50.)

56. Show the construction of a slide-valve and cylinder ports by sketching a section

valve and piston rods.

taken through the axes of the Determine and insert figures

showing the dimensions suitable under the following circumstances:

Diameter of cylinder, 15".

Speed of piston, 500 feet per minute.

Length of cylinder ports, 12".

Angle of crank at admission of steam, 6°.

Cut off at three-fourths the stroke.

No inside lap.

N.B.-Show the calculations and diagrams by means of which your estimations were made.

(50.)

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