. The Street railway journal . he exhaust pipe. With a26-in. vacuum in ordinary working the feed water should leave theprimary heater at a temperature about 25 degs. above that of thehotjvell, say at 125 degs. From the primary heater the feed waterpasses to the vertical auxiliary heater, into which is discharged at atmospheric pressure all the exhaust steam from the feed, con-denser and other steam pumps, small engines or any other auxiliaryapparatus, the temperature of the feed water being raised nearly toboiling point. With this arrangement of heaters it is not generallyeconomical to use a c
. The Street railway journal . he exhaust pipe. With a26-in. vacuum in ordinary working the feed water should leave theprimary heater at a temperature about 25 degs. above that of thehotjvell, say at 125 degs. From the primary heater the feed waterpasses to the vertical auxiliary heater, into which is discharged at atmospheric pressure all the exhaust steam from the feed, con-denser and other steam pumps, small engines or any other auxiliaryapparatus, the temperature of the feed water being raised nearly toboiling point. With this arrangement of heaters it is not generallyeconomical to use a condenser driven from the engine shaft, be-cause the exhaust steam from an independent condenser is usuallyrequired in the auxiliary heater to insure economical results, but incases where the exhaust from the auxiliary machinery is more thansufficient to do the work, a part of such auxiliary apparatus maybe exhausted into the primary heater, and thus work under vacuumwith increased economy. Where the available amount of exhaust. Brt^uienl Floor FIG. 3.—ARRANGEMENT OF FEED WATER HEATERS steam is insufficient, however, the required amount of steam maybe secured by bleeding the high-pressure exhaust of a compoundengine or by taking steam direct from the boiler through a re-ducing valve. As to the relative sizes of the heaters it is consideredgood practice to have them of equal capacity, the work to be donebeing usually about the same in each. The primary heater is ar-ranged to drip at the lower end, and the heaters are usually soby-passed as to permit either one to be used independently whennecessary. As the primary heater itself acts as a partial con-denser its use causes no impairment of the vacuum, while the factthat there are no threaded or expanded joints in the tubing, allconnections being made by lapping and brazing, is a safeguardagainst any leakage tnat would prove detrimental to the main-tenance of the vacuum. The heaters described are manufacturedby the Whitlock Coil P
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
