. Electrical world. densers for steamturbines, from 10 to 12 pounds of steam are condensed per square footper hour, at which rate of condensation a vacuum may be obtained atfrom 27]/2 to 28 in. at full load. The amount of cooling water gen-erally allowed is about 50 times the full load steam consumption,which will increase the vacuum under normal conditions by about^ in. or I in. over that obtained by the usual circulating allowanceof 30 times the steam used. With a proper arrangement of pipesand condensers in a plant taking 18 pounds of steam per kw-hourand assuming 50 per cent, efficiency in
. Electrical world. densers for steamturbines, from 10 to 12 pounds of steam are condensed per square footper hour, at which rate of condensation a vacuum may be obtained atfrom 27]/2 to 28 in. at full load. The amount of cooling water gen-erally allowed is about 50 times the full load steam consumption,which will increase the vacuum under normal conditions by about^ in. or I in. over that obtained by the usual circulating allowanceof 30 times the steam used. With a proper arrangement of pipesand condensers in a plant taking 18 pounds of steam per kw-hourand assuming 50 per cent, efficiency in the pump and motor, the powerused by the circulating pump is only i per cent.; by circulating water30 times the steam consumption it would be .6 per cent., w-hich smallreduction is not to be compared with the gain of 4 or 5 per cent,in the turbine by the use of increased circulating water. The paper described a vacuum augmenter which has recently beenintroduced and which is illustrated in Fig. 3. A pipe is led from. FIG. 3-—ARRANGEMENT OF VACUUM AUGMENTER. near the bottom of the main condenser to an auxiliary condenserhaving generally about 1/20 the cooling surface of the main con-denser. In a portion of this pipe a small steam jet is placed whichacts in the same way as a steam exhauster and sucks nearly allthe residual air and vapor from the condenser and delivers it to theair pumps. A water seal is provided, as shown, to prevent the airand vapor from returning to the condenser. With this arrangement,if there is a vacuum of 27^2 or 28 in. in the condenser there may beonly about 26 in. in the air pump, which, therefore, need only beof small size, the jet compressing the air and vapor from the con-denser to about half or less of its original volume. The steam jetused only about iVz per cent, of the quantity of steam used by theturbine at full load. Condensation takes place in the condenser muchmore rapidly and effectually if the air is thoroughly extracted. In Fig. 2. which r
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
