Science and Industry, Հատոր 7Colliery Engineer Company, 1902 |
From inside the book
Արդյունքներ 100–ի 1-ից 5-ը:
Էջ 7
... part of the heat that is useful to us . The loss of heat at the chimney will generally run from 20 to 40 per cent . One pound of pure carbon when burned will yield an average of 14,500 heat units , each equal to 778 ft . lbs 7.
... part of the heat that is useful to us . The loss of heat at the chimney will generally run from 20 to 40 per cent . One pound of pure carbon when burned will yield an average of 14,500 heat units , each equal to 778 ft . lbs 7.
Էջ 8
... cent . of the heat is used . The rule for finding the efficiency of a boiler is as follows ( see " Foley's Mechanical Engineers ' Reference Book " ) : " Given the heat value of the fuel in thermal units per pound , and the number of ...
... cent . of the heat is used . The rule for finding the efficiency of a boiler is as follows ( see " Foley's Mechanical Engineers ' Reference Book " ) : " Given the heat value of the fuel in thermal units per pound , and the number of ...
Էջ 26
... cent .; to 1 H. P. , 50 to 60 per cent .; 1 to 2 H. P. , 60 to 75 per cent . ; 2 to 3 H. P. , 75 to 85 per cent . ; 3 to 5 H. P. , 85 to 90 per cent .; 5 to 10 H. P. , 90 to 95 per cent . Also , as a guide to the power required to drive ...
... cent .; to 1 H. P. , 50 to 60 per cent .; 1 to 2 H. P. , 60 to 75 per cent . ; 2 to 3 H. P. , 75 to 85 per cent . ; 3 to 5 H. P. , 85 to 90 per cent .; 5 to 10 H. P. , 90 to 95 per cent . Also , as a guide to the power required to drive ...
Էջ 27
planer , punch press not used during test , average 4.87 H. P. 47 per cent . being required to drive shaft and belt overhead from motor on the floor . Test No. 12. Group of 20 machines , 8 lathes , 4 milling machines , 3 planers and ...
planer , punch press not used during test , average 4.87 H. P. 47 per cent . being required to drive shaft and belt overhead from motor on the floor . Test No. 12. Group of 20 machines , 8 lathes , 4 milling machines , 3 planers and ...
Էջ 35
... pounds . ON is the clearance volume = 8 per cent . of the piston displacement . The line PQ is drawn from OR to some point on the compression line . From C , a point on the expansion line just before WHAT THE INDICATOR DIAGRAM TELLS US 35.
... pounds . ON is the clearance volume = 8 per cent . of the piston displacement . The line PQ is drawn from OR to some point on the compression line . From C , a point on the expansion line just before WHAT THE INDICATOR DIAGRAM TELLS US 35.
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Common terms and phrases
alternating current amount ampere-turns amperes angle armature battery belt binding post boiler brass carbon cent circuit circular mils coal coil condenser connected copper crosshead cut-off cylinder diagram diameter direct current direction distance dynamo efficiency electric electromotive force engine equal feedwater feet field fire flow force formula friction fuel furnace give given grate heater heating surface holes horsepower increase iron joint lamp length load machine machinery magnetic mean effective pressure means mechanical metal method motor necessary number of turns obtained ohms operation pipe piston plant plates pounds practical pressure pulley pump resistance revolutions per minute rheostat SCIENCE AND INDUSTRY Scranton shaft shown in Fig shunt side speed square inch steam steam engine steel stroke superheated switch tank temperature tion tubes turbine valve voltage voltmeter volts weight wheel winding wire
Սիրված հատվածներ
Էջ 632 - AH a unit of resistance, the international ohm, which is based upon the ohm equal to 109 units of resistance of the CGS system of electromagnetic units, and is represented by the resistance offered to an unvarying electric current by a column of mercury at the temperature of melting ice, 14.4521 grams in mass, of a constant cross-sectional area and of the length of 106.3 centimetres.
Էջ 455 - Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it is compelled by force to change that state.
Էջ 512 - Every body continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it.
Էջ 258 - Bushings must be long enough to bush the entire length of the hole in one continuous piece, or else the hole must first be bushed by a continuous waterproof tube.
Էջ 240 - In the history of mechanical art two modes of progress may be distinguished — the empirical and the scientific. Not the practical and the theoretic, for that distinction is fallacious : all real progress in mechanical art, whether theoretical or not, must be practical. The true distinction is this : that the empirical mode of progress is purely and simply practical ; the scientific mode of progress ia at once practical and theoretic.
Էջ 258 - Must be placed on all service wires, either overhead or underground, as near as possible to the point where they enter the building and inside the walls, and arranged to cut off the entire current from the building.
Էջ 141 - L = length of stroke, in feet; A = area of piston, in square inches; N = number of strokes per minute = number of revolutions x 2. PLAN " " " 33,000 ' The derivation of this formula is explained, as follows: The area of the piston, in square inches, multiplied by the mean effective pressure, in pounds per square inch, gives the total force acting on the piston, in pounds.
Էջ 258 - No. 51.) a. Must be placed on all service wires, either overhead or underground in a readily accessible place, as near as possible to the point where the wires enter the building, and arranged to cut off the entire current.
Էջ 258 - In all wiring special attention must be paid to the mechanical execution of the work. Careful and neat running, connecting, soldering, taping of conductors and securing and attaching of fittings, are specially conducive to security and efficiency, and will be strongly insisted on.