248

DETAILS OP SCREW ENGINES.

the condenser, and both are sufficiently highabove the pumps to enable a free passage forthe water. At the back end of the con-denser the discharge chambers are connectedby passages, and thus one discharge pipe only

Pig. 76 .

MESSES. HUHPHRYS’ INJECTION CONDENSER FOR DIRECTACTING ENGINES.

is requisite. The suction valves are invertedin the bottom of the condenser at an angle ;and the discharge valves, with a reverseaction, are secured in the bottom of the dis-charge chambers.

The valves are the flat kind, almost squarein plan—the seating being perforated in theordinary manner. The guards are twin-angular, and thus the valve rises and falls oneach side of its connection.

The exhaust steam enters the condenserat the front end, below the roof, and theinjection water directly opposite. The doorsfor access to the valves are at the sides andtop of the respective chambers.

The following dimensions are the generalpractice of the firm in question for a pairof engines of 400 horse power nominal collec-tively Ft m.

Diameter of Pumps, 2 . . . . 1 10

Length of Stroke . . . . .30

Diameter of Pump Rod . . , . 0 2|

Size of Valve (9x7 inches.)

Number of Suction Valves, 48.

Ft. In.

Number of Discharge Valves, 48.

Diameter of Injection Pipe . . .08

Diameter of Discharge Pipe . . .20

The arrangement next under comment is

that by Messrs. J. and W. Dudgeon, represented

by Fig. 77. The central compartment is the

Pig. 77.

MESSRS. DUDGEON’S INJECTION CONDENSER FOR DIRECTACTING ENGINES.

discharge chamber—common to both pumps—•and the condensers are on each side of the same.The suction valves, of the disc kind, areinverted at an angle, as in the previousexample ; also the disposition of the dischargevalves are similar. The exhaust steam entersthe front of the condensers below the roof,and the injection water flows in at the sides,to render a vacuum certain.

This arrangement may be said to be a com-bination of those represented by Figs. 75—page 247—and 76—in relation to the positionsof the respective chambers, pumps, &c.

The doors, for internal access to the suctionand discharge valves, are at the front, back, andsides of the chambers. The discharge openingis at the back end and directly below the roof-The example under notice has been fitted byMessrs. Dudgeon in the mail steamer “ Mary

. i

Augusta.” The engines are 300 nonnna