The exhaust steam induction condenser is based upon the same principle heretofore explained under the section relating to injectors. See Fig. [585].
Fig. 585.
The exhaust steam enters through the nozzle, A. The injection water surrounds this nozzle and issues downward through the annular space between the nozzle and the main casting. The steam meeting the water is condensed, and by virtue of its weight and of the momentum which it has acquired in flowing into the vacuum the resulting water continues downward, its velocity being further increased, and the column solidified by the contraction of the nozzle shown. The air is in this way carried along with the water and it is impossible for it to get back against the rapidly flowing steam in the contracted neck. The condenser will lift its own water twenty feet or so. When water can be had under sufficient head to thus feed itself into the system, and the hot-well can at the same time be so situated as to drain itself, it makes a remarkably simple and efficient arrangement. In case the elevation is so great that a pump has to be used to force the injection, the pump has to do less work than the ordinary air pump, and its exhaust can be used to heat the feed water.
The Bulkley “Injector” condenser is shown in Fig. [586], arranged so that the condensing water is supplied by a pump. The condenser is connected to a vertical exhaust pipe from the engine, at a height of about 34 feet above the level of the “hot-well.” An air-tight discharge pipe extends from the condenser nearly to the bottom of the “hot-well,” as shown in the engraving.
The condenser is supplied by a pump as shown, or from a tank, or from a natural “head” of water; the action is continuous, the water being delivered into the “hot-well” below. The area of the contracted “neck” of the condenser is greater than that of the annular water inlet described above, and the height of the water column overcomes the pressure of the atmosphere without.
Fig. 586.
The supply pump delivers cool water only, and is therefore but one-third of the size of the air-pump. The pressure of the atmosphere elevates the water about 26 feet to the condenser.