The Volz apparatus is a combined condenser and feed-water heater; the shell or exhaust steam chamber contains a set of tubes, through which the feed-water passes, while the lower part contains the condensing tubes, both parts being in proper communication with their respective water chambers. The heater tubes being located immediately adjacent to the exhaust inlet, are exposed to the hottest steam, and the feed-water becomes nearly as high temperature as that of the vacuum. Pages 304 and 305 show the sectional and outside views. The enclosing shell containing the combined heater and condenser is a well ribbed cylindrical iron casting; free and independent access is provided to either set of tubes by removing corresponding heads.
The illustration, Fig. [584], is a longitudinal section of one side of the condenser pump, and also a section of the condenser cone, spray pipe, exhaust elbow and injection elbow. “A” is the exhaust to which is connected the pipe that conducts to the apparatus the steam or vapor that is to be condensed. The injection water is conveyed by a pipe attached to the injection opening at “B.” “C” is the spray pipe, and has, at its lower extremity, a number of vertical slits through which the injection water passes and spreads out into thin sheets.
The spray cone “D” scatters the water passing over it, and thus ensures a rapid intermixture with the steam. This spray cone is adjustable by means of a stem passing through a stuffing-box at the top of the condenser, and is operated by the handle “E.” The cone should be left far enough down to pass the quantity of water needed for condensation.
All regulation of the injection water must be done by an injection valve placed in the injection pipe at a convenient point.
Note.—The surface condensers, Figs. [579]-[581], are made by the Wheeler Condenser and Engineering Co., New York, as are also the Volz combined surface condenser and feed water heater, shown in Figs. [582] and [583].
The operation of this condensing apparatus is as follows: steam being admitted to the cylinders “K,” so as to set the pump in motion, a vacuum is formed in the condenser, the engine cylinder, the connecting exhaust pipe, and the injection pipe. This causes the injection water to enter through the injection pipe attached at “B” and spray pipe “C” into the condenser cone “F.” The main engine being started, the exhaust steam enters through the exhaust pipe at “A,” and, coming in contact with the cold water, is rapidly condensed. The velocity of the steam is communicated to the water, and the whole passes through the cone “F” into the pump “G” at a high velocity, carrying with it, in a comingled condition the air or uncondensable vapor which enters the condenser with the steam. The mingled air and water is discharged by the pump through the valves and pipe at “J” before sufficient time or space has been allowed for separation to occur.
Fig. 584.