. Electric railway review . ght to justify the useof additional apparatus. There is a special designof elevated jet condenserwhich employs two tail pipes,one being restricted in sizeand designed for a highwater velocity to eject the airand discharge it into the hotwell. The other tail pipe,which is of sufficient size tocarry away all the waterwhich the ejection pipe willnot discharge, has its openingfrom the condenser bowl ata higher elevation than theejection pipe opening. Acondenser designed on thisprinciple is shown in (J 1-1) and it has beenclaimed that a vacuum of 26and 27 inches
. Electric railway review . ght to justify the useof additional apparatus. There is a special designof elevated jet condenserwhich employs two tail pipes,one being restricted in sizeand designed for a highwater velocity to eject the airand discharge it into the hotwell. The other tail pipe,which is of sufficient size tocarry away all the waterwhich the ejection pipe willnot discharge, has its openingfrom the condenser bowl ata higher elevation than theejection pipe opening. Acondenser designed on thisprinciple is shown in (J 1-1) and it has beenclaimed that a vacuum of 26and 27 inches has been main-tained with a high tempera-ture of the water in the hotwell, and no other means pro-vided for removing the airother than the air ejectiontail pipe. This being thecase, but very little additionalmachinery and apparatus isrequired with this condensingarrangement, the circulatingpump being any one of thestandard low pressure de-signs, the one which is mostflexible and efficient being adirect connected engine type. Figure 269—(J1-1). centrifugal pump, the exhaust of which is piped to the feedwater heater. A motor driven pump is quite attractive to operating engi-neers on account of its simplicity and reliability, but it ismuch less efficient than an engine driven pump, the exhaustof which is used for feed heating. A difficulty which is expe-rienced with motor-driven centrifugal pumps is that of start-; .ii>!user without a dry vacuum pump, as the water must then be raised to about twice its normal elevation, asChe water in the tail pipe is not there to balance a column ofequivalent height in the injection pipe. The speed of themotor being fixed, and the centrifugal pump not being capableof raising water much above the bead lor which it was de-signed, it is necessary to have the motor constantly drivinga high lift pump for low lift service. In the case of engine driven pumps, however, it is possible to temporarily increasethe speed of the engine sufficiently to sta
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectstreetr, bookyear1906
