THE SUBWAYS AND TUNNELS OF NEW YORK: METHODS AND COSTS

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Page 351 - ... speed), divide the number of gallons by 4 then extract the square root, and the product will be the diameter in inches of the pump cylinder. To find quantity of water elevated in one minute...
Page 297 - in both Fig. i and Fig. 2, must ream the outer edge of the hole and keep it round and free from rifles. In Fig. 2 it will be noted that the circle described by the corners of the bit at the base of the bevel is much smaller than the circle described by the chisel edges. This causes an excess of wear on the corners of the chisel edges, the bit rapidly loses its gage, as well as its efficiency, and it is almost impossible to keep the hole round. Rifles form and these cause the rotation parts of the...
Page 297 - ... without the attendant difficulties of resharpening. With this bit, as in the case of the X-bit, the piston must revolve a half turn before the cutting edges will strike in the same place a second time. It is as easily resharpened as the regular square cross-bit. The X-bit itself is shown in Fig.
Page 290 - ... of impact of the steel upon the rock. Perhaps the most gratifying, and also surprising, revelation of all in connection with the Electric-Air drill is the now indisputable fact that it takes only from one-third to one-fourth of the power, at the power-house, to drive it to do the same work. This is accounted for by the fact that the same air is used over and over, and that all of its elastic force is availed of in both directions instead of exhausting the charge for each stroke at full pressure....
Page 289 - ... is accelerated. In the same way by the action of the other pulsator piston the opposing pressure upon the advancing side of the drill piston is a diminishing pressure instead of the constant atmospheric resistance, and these combined cause a greater unbalanced difference of pressures upon the opposite sides of the drill, a more rapid acceleration of the piston movement and a consequent higher velocity and force at the moment of impact of the steel upon the rock. • Perhaps the most gratifying...
Page 346 - ... compared with two-stage isothermal, is 91.7 per cent. Volumetric efficiency is 94.2 per cent. Taken as a whole, this is a splendid record of performance; though some slight defects may be noted in the details of the cards.
Page 7 - They read as follows: 1 . Never enter the caisson with an empty stomach. 2. Use as far as possible a meat diet, and take warm coffee freely. 3. Always put on extra clothing on coming out, and avoid exposure to cold. 4. Exercise as little as may be during the first hour coming out, and lie down if possible. 5. Use intoxicating liquors sparingly; better not at all. 6. Take at least eight hours
Page 351 - Petroleum weighs 6} pounds per US gallon, 42 gallons to the barrel. To convert imperial gallons into US gallons, multiply by the factor 1.2. To convert US gallons into imperial gallons, multiply by the factor .8333. A...
Page 346 - The reduction of pressure produced by elbows and tees is equal to two-thirds of that caused by globe valves. The following are the additional lengths of straight pipe to be taken ii to account for elbows and tees.
Page 301 - Fig. 19 is the same bit at about the time that the original cross that was formed on the bar of octagon steel has become exhausted. The other system of hand-sharpening is known as the fuller and dollie system. By this system the stock is first drawn sharp at the corners as shown in Fig.

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