Centrifugal pumping machinery: the theory and practice of centrifugal and turbine pumps

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McGraw-Hill, 1912 - Technology & Engineering - 184 pages
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Page 166 - ... expansion in the moving blades is added to the impulse of the steam as received from the fixed nozzles. Third. Zoelly and Rateau; impulse turbine having a series of partial expansions, the energy of each expansion being absorbed in a single row of moving blades. Fourth. Curtis; where the velocity of the steam from the nozzles is absorbed in and passes through several rows of moving blades. All other types are modifications of these. There are certain points towards which the effort of designers...
Page 27 - ... in one direction, as milling machines, gear cutting machines, chucking machines. But, by running the pump independently, it can be used on machines that reverse. It is simple in construction, the principal mechanism being a pair of gears which run together in a tight case. To obtain the best results the pump should be placed as near as possible to the level of the liquid in the tank.
Page 29 - Before starting new or unused centrifugal pumps, it is advisable to clean out the bearings thoroughly, including the thrust bearing, by pouring in kerosene and allowing it to run out at the bottom, as dirt is liable to get in during shipment or idleness.
Page 14 - Calculated from the formula k — — 48. Efficiency of Pumps. — The word efficiency used in connection with pumping machinery has become very ambiguous and has led to many unnecessary disputes in the interpretation of guarantees and contracts. This has been brought about by the fact that the word has been used without modification to designate the efficiency of the pump only, the pump and prime mover, and of the entire plant back to the boiler. This uncertainty can be and should be eliminated...
Page 29 - If the head pumped against is greater than that for which the pump was designed, the quantity of water discharged will be less, and may be reduced to zero under very excessive heads.
Page 103 - ... working, and at full head the water coming through them will exert a pressure of 130 pounds to the square inch, the equivalent of a ton and one-half of pressure against a bank 100 feet away within range of the deflectors. As it is expected that the positions of the monitors will be shifted frequently their bases are of temporary construction. The...
Page 28 - J-inch pipe from the discharge of the pump should be run to the stuffing box and an opening connected through to the cage. This makes a water seal in the stuffing box and prevents all air leakage. The gland should be run as loose as possible, otherwise the packing is liable to cut the shaft. A small amount of leakage from the stuffing box does no harm, in fact is an advantage, as it prevents the packing from heating and at the same time keeps it lubricated.
Page 103 - The frictional resistance is decreased by a ball-bearing, and a weighted lever is attached to control the direction of the jet. A deflecting nozzle is fitted to the discharge end of the giant, which permits deflections through a small angle without changing the position of the main body. The tapering piece of the giant is fitted on the inner side with two sets of guide vanes which prevent a scattering or rotary motion of the water after it has issued from the nozzle. The nozzles used will vary from...
Page 161 - ... conditions. Where the head must vary, this may be accomplished by changing the speed, and a motor must be selected which permits speed regulation. The designer of the pump must, therefore, carefully consider the nature of his motor when laying out the characteristics of his impeller. On the other hand, the electrical engineer should design his motor to suit the characteristics of the pump.
Page 166 - ... of secondary importance, as low cost of operation will offset increased steam consumption. The rating of steam turbines in connection with pumps should always be on the maximum load, as otherwise the expected efficiency will not be obtained. There are four principal types of steam turbines : First. De Laval; an impulse turbine in which the steam is completely expanded in a single set of nozzles and all the kinetic energy is given up to a single row of blades. Second. Parsons...

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