cilities for accurate steam-consumption calculations than those plants
in which the condensed exhaust steam and the circulating water come into
actual contact, it being necessary with this type simply to pump the
condensed steam into a weighing or measuring tank.

In the case of a single-flow turbine of the Parsons type, the covers
should be taken off and every row of blades carefully examined for
deposits, mechanical irregularities, deflection from the true radial and
vertical positions, etc. The blade clearances also should be gaged all
around the circumference, to insure this clearance being an average
working minimum. On no account should a test be proceeded with when any
doubt exists as to the clearance dimensions.

[Illustration: FIG. 60]

The dummy rings of a turbine, namely, those rings which prevent
excessive leakage past the balancing pistons at the high-pressure end,
should have especial attention before a test. A diagrammatic sketch of a
turbine cylinder and spindle is shown in Fig. 60, for the benefit of
those unfamiliar with the subject. In this A is the cylinder or casing,
B the spindle or rotor, and C the blades. The balancing pistons, D, E,
and F, the pressure upon which counterbalances the axial thrust upon the
three-bladed stages, are grooved, the brass dummy rings G G in the
cylinder being alined within a few thousandths of an inch of the grooved
walls, as indicated. After these rings have been turned (the turning
being done after the rings have been calked in the cylinder), it is
necessary to insure that each ring is perfectly bedded to its respective
grooved wall so that when running the several small clearances between
the groove walls and rings are equal. A capital method of thus bedding
the dummy rings is to grind them down with a flour of emery or
carborundum, while the turbine spindle is slowly revolving under steam.
Under these conditions the operation is performed under a high
temperature, and any slight permanent warp the rings may take is thus
accounted for. The turbine thrust-block, which maintains the spindle in
correct position relatively to the spindle, may also be ground with
advantage in a similar manner.

The dummy rings are shown on a large scale in Fig. 61, and their
preliminary inspection may be made in the following manner:

The spindle has been set and the dummy rings C are consequently within a
few thousandths of an inch of the walls _d_ of the spindle dummy grooves
D. Th