toothed heads C and D
shrunk upon them, the heads being secured by the nuts E and F. The
teeth in this case are cut in the enlarged ends as shown. A sleeve G,
made in halves, fits over the heads, and the teeth cut in each half
engage with those of their respective heads. All the teeth and teeth
faces are cut radially, and a little side play is allowed.

The Condenser

To some extent, as previously remarked, the condenser and condensing
arrangements are instrumental in determining the lines upon which a test
ought to be carried out. In general, the local features of a plant
restrict the tester more or less in the application of his general
methods. A thorough inspection, including some preliminary tests if
necessary, is as essential to the good conduct of the condensing plant
as to the turbine above it. It may be interesting to outline the usual
course this inspection takes, and to draw attention to a few of the
special features of different plants. For this purpose a type of
vertical condenser is depicted in Fig. 69. Its general principle will be
gathered from the following description:

Exhaust steam from the turbine flows down the pipe T and enters the
condenser at the top as shown, where it at once comes into contact with
the water tubes in W. These tubes fill an annular area, the central
un-tubed portion below the baffle cap B forming the vapor chamber. The
condensed steam falls upon the bottom tube-plate P and is carried away
by the pipe S leading to the water pump H. The Y pipe E terminating
above the level of the water in the condenser enters the dry-air pump
section pipe A. Cold circulating water enters the condenser at the
bottom, through the pipe I, and entering the water chamber X proceeds
upward through the tubes into the top-water chamber Y, and from there
out of the condenser through the exit pipe. It will be observed that the
vapor extracted through the plate P passes on its journey out of the
condenser through the cooling chamber D surrounded by the cold
circulating water. This, of course, is a very advantageous feature. At R
is the condenser relief, at U the relief valve for the water chambers.

[Illustration: FIG. 69]

A new condenser, especially if it embody new and untried features,
generally requires a little time and patience ere the best results can
be obtained from it. Perhaps the quickest and most satisfactory method
of getting at the weak points of this portion of a plant is to test the