"TRENT" TURBINES. UNI £63 £70 £80 £105 £125 £165 £200 £235 £300 £450 "NEW VICTOR" TURBINE. A VERTICAL PATTERN. Diameter in Inches. 6 Cost with case 73 97 117 15 19 23 27 31 35 398 431 £25 £30 £35 £40 £50 £65 £80 $125 $150 $175 $200 $250 $325 $400 471 511 55 £90 £110 £135 £165 £200 $450 $550 $675 $825 $1,000 CENTRAL DISCHARGE TURBINES, SUCH AS THE "WAVERLEY," ETC. Diameter in Inches 6 8 IO 12 131 18 20 24 26 30 35 38 42 48 52 55 £21 £27 £31 £35 £41 £51 £61 £71 $105 $135 $155 $175 $205 $255 $305 $355 £28 £34 £40 £47 £55 £66 £77 £90 $140 $170 $200 $235 $275 $330 $385 $450 Cost, vertical with £24 $120 Cost, horizontal £75 £93 £120 £147 £175 £200 £220 £240 £265 £290 $375 $465 $600 $735 $875 $1,000 $1,100 $1,200 $1,325 $1,450 case. with case. "LITTLE GIANT DOUBLE " TURBINE. £28 £32 £36 £40 £45 £50 £55 £60 £70 £95 £120 £150 $140 $160 $180 $200 $225 $250 $275 $300 $350 $475 $600 $750 Cost of Turbines. The preceding figures of cost of various turbines are not designed to indicate any comparative advantages which each may possess, but are simply tabulated with a view to affording a comparison between the cost of a turbine installation and that of any other prime motor. The prices are in all cases copied from manufacturers' lists. They are taken in the order mentioned in our preliminary remarks. Water-pressure Engines.-These useful little engines are of a high comparative efficiency, and are made in several forms. The best known are those of Ramsbottom, Haag & Rigg. They usually consist of a cylinder or cylinders oscillating upon trunnions, and connected without a crosshead to a cranked shaft. An air-vessel is provided by which the shocks of the cutting-off of the supply by the movable ports, or valve-gears, are mitigated. In the first and last mentioned types three cylinders are employed, thus dividing the duty around the circle. The writer designed one in which four were employed, each receiving pressure only during one-fourth of the stroke, and that fourth being the most effective portion upon the crank. During the remainder of the stroke each plunger drew water from its neighbor, which was at that time on its return stroke. By a simple arrangement of cross-ports each piston became its own valve. Such an arrangement may be expected to give a very high useful effect. Other designs have been made in which, the crank being fixed, the cylinders turn around it, being enclosed in a suitable casing. This is a very useful type for capstan work. The general efficiency of these machines may run as high as 80 per cent. The stroke of these engines is usually about 4 to 41⁄2 times the bore of the cylinder, and the piston speed employed about 60 feet per minute. The power is to be found as follows: Q = Quantity of water in cubic feet per minute. H= Head in feet. The effective power will = .00151 × Q × H. The supply of water should be free, and angles and sharp bends should be avoided. The velocity of the supply should not exceed 400 feet per minute. The proper diameter of supply pipe: For single-cylinder engines = bore of cylinder in inches x .41 = diameter of supply-pipe in inches. For double-cylinder engines = bore of cylinder in inches x .68 diameter of supply-pipe in inches. Where a high-pressure water-supply exists at a very cheap rate, these engines will be found clean and efficient motors for small powers. They may be located anywhere at will, and fixed as easily as a small steam-engine, but should not be used with pressures less than 20 lbs. per square inch. In cases where the risk of fire would cause extra premiums for insurance, these water-engines would be found a good substitute for a steam-engine, and possess particular advantages over the latter as regards cleanliness, absence of smell, and readiness for immediate operation. Against these must be set the liability to freeze up unless protected from the action of frost. PARTICULARS AND COST OF THREE-CYLINDER WATER-ENGINES. Schmid's is another type of single-cylinder water-pressure engine which has given a very high percentage of useful effect under trial, and is designed for use with a highpressure supply. It is stated that so high a percentage as 89 has been reached in effective work with these engines. In most of them by reversing the action the machine becomes a good pump, the exhaust pipe being then the suction and the supply becoming the delivery pipe. GENERAL PARTICULARS AND POWERS OF SINGLE-CYLINDER WATERPRESSURE ENGINES. Diam. of Cylinder. 1′′ 2′′ Revs. per minute. Imp. gals.of wat- 300' head=129.9 2" 2" 3" 4" 5' 9" 300 275 6" 460 930 1,525 2,275 4,200 6,900 10,260 15,000 20,920 30,080 36,780 .57 .35 .75 .43 95 |