MECHANICAL ENGINEERING.-PART I. FIRST PAPER. The Board of Examiners. 1. Write a short Essay on the various methods used for utilizing human power to drive machinery. 2. Describe and sketch a windmill of about 1 horsepower for pumping water, and explain clearly how it is prevented from racing and causing injury during gusts of special intensity. 3. Describe and sketch a gravity water-wheel suitable for a fall of 20 feet, and a discharge of 3 cubic feet per second. Calculate its power, and the number of revolutions per minute it should make, and point out the various sources of loss, showing how they may be obviated. 4. Draw a neat section of the cylinder piston and slide valve of a small steam-engine, and explain how the valve is proportioned so as to cut off the steam before the end of the stroke, and at the same time obtain a free exhaust and a sufficient amount of cushioning. 5. Describe the construction and mode of testing the gas-engine in the laboratory, giving as many numerical results as you can. MECHANICAL ENGINEERING.-PART I. SECOND PAPER. The Board of Examiners. 1. Write an essay on the Indicator, showing how its construction has been modified to suit the higher pressures and speeds adopted in modern practice. Illustrate your answer by neat sketches of various forms of indicator and diagrams such as you would expect to obtain from various forms of steam and gas engines. 2. Make neat sketches fully detailed and dimensioned of a stationary steam boiler of ordinary form, with all its necessary fittings, suitable for a simple non-condensing engine of about 70 indicated horse-power, and give a brief description of the same. 3. Describe fully the method you would adopt to make a complete test of an engine and boiler, such as one of those in the City Electrical Station. 4. Write an essay on external and internal combustion air engines, and illustrate the same with sketches of as many forms as you can, and numerical results of their performances. 5. Briefly describe the construction and use of the following instruments:- (a) Fuel calorimeter. (b) Steam calorimeter. (c) Absorption dynamometer. MECHANICAL ENGINEERING.-PART II. The Board of Examiners. 1. Describe fully, with sketches, the following:- (d) Hooke's universal joint. 2. Give all the information you can as to the best methods of proportioning the teeth of wheels in view of strength and smooth running. 3. Describe and criticise the following forms of pump : (a) Single-acting plunger pump. (b) Bucket and plunger pump. (c) Two-cylinder double-acting pump, with cranks at right angles. (d) Three-cylinder single-acting plunger pump, with 4. Describe fully, with sketches, the following:- (d) A three-phase generator. 5. Write an Essay on the transmission of power by electricity for railway, tramway, and factory purposes, comparing it with the steam locomotion, the cable tramway, and shafting and belts respectively. K HYDRAULIC AND SANITARY ENGINEERING, INCLUDING IRRIGATION. (FOURTH YEAR B.C.E.) FIRST PAPER. The Board of Examiners. 1. Examine the conditions necessary for the existence of a standing wave in a channel of uniform section throughout. A smooth concrete channel rectangular in section is 4 feet wide, and has a fall of 2 feet per mile. A sluice-gate is placed in the channel which heads the water up, above the gate, to a height of 4 feet, and the gate is opened 1 inch. Determine (a) The depth of water in the channel when the flow has become regular. (b) The mean velocity of the water at the foot of the standing wave. (c) The flow in the channel remaining as above, determine the opening of the gate at which the standing wave will commence at the gate, and the corresponding depth of water in the channel above the gate. 2. An artesian bore is 3,000 feet deep and lined throughout with 5-inch iron casing. The static pressure is 150 lbs. per square inch, and the free flow 400,000 gallons per day. Determine the horse-power available with a motor of 75 per cent. efficiency. If an 18-inch Pelton wheel is to be used, at what speed should it run? 3. Design a jet elevator to raise 8,000,000 gallons of clean water per day a vertical height of 10 feet through 300 feet of 12-inch wrought-iron pipes. The pressure water has a working head of 500 feet near the nozzle. Determine the efficiency of the plant. HYDRAULIC AND SANITARY ENGINEERING. SECOND PAPER. The Board of Examiners. NOTE.-ONE question only to be answered. (a) Design a water tower of iron throughout to hold 60,000 gallons. Top water level 80 feet above ground, and low water level 60 feet above ground. Prepare sketches for working drawings of all essential details. Take out the quantities of each class of ironwork in the tank, and prepare an estimate of the cost. Or, (b) Design an inverted siphon to carry 20,000,000 gallons of sewage per day under a river in which the water is 20 feet deep; bottom width, 200 feet, and 4 to 1 side slopes; depth from surface to bottom of river, 25 feet. The material of both banks and bottom is silt The invert level of the sewer before it reaches the river is 15 feet below natural surface. Draw up a specification for placing the siphon in position, after its construction on one of the banks of the river. |