262
DETAILS OP SCREW ENGINES.
Ft. In.
Inside Diameter of Tubes
. 0
Of rV
Outside ditto ....
. 0
Oi
Length between Plates .
. 7
1
Number of Tubes, 2,506.
Diameter of Air Pumps, 2
. 0
10
Diameter of Circulating Pumps, 2 .
. 0
10
Length of Stroke ....
. 2
0
Diameter of Pump Rod (air) .
. 0
n
Ditto ditto (circulating)
. 0
2f
Diameter of Suction Valves .
. 0
Ditto of Discharge ditto
. 0
H
Number of each Set, 12.
Diameter of Supply Water Pipes, 2
. 0
6*
Diameter of Discharge Pipe .
. 0
10
SURFACE CONDENSERS FOR RETURN ACTION
channels, each being worked by the oppositesteam pistons. The valves are rectangular,located at an angle on each side of the barrel—the discharge chambers being outside thepiston rods of each engine. The circulatingwater is intercepted at three points during itstraverse, and thus a return action within thetubes is effected, similar to that described inpage 259, in relation to Fig. 86—page 260.
The practice of Messrs. Napier being worthyof attention, the following dimensions in rela-tion to Fig. 89 are introduced:—
Ft. In.
ENGINES.
The remarks given in page 249, in relationto injection condensers, very nearly apply inthe present case. The piston and connectingrods in each instance cut up the condenser,and thus the arrangement is, of course, dulyeffected. The illustration depicted by Fig. 89
Fig. 89.
messes, napier’ s surface condenser for return action
ENGINES.
Inside Diameter of TubesOutside ditto dittoLength of ditto between PlatesNumber of Tubes, 3,923.
Diameter of Air PumpDitto of Circulating Pump .
Length of StrokeDiameter of Pump Rod (air)
Ditto ditto (circulating)Sizes of Valve Gratings (27£ x 5 ins.)Number of Valves to each Pump, 4.Diameter of Supply Water PipeDiameter of Discharge Pipe .
0 0| full.
0 0 |
6 3
I 4
1 4
2 60 2 f0 2 £-
1 41 4
Messrs. Maudslay, Sons, and Field have beenmentioned as originators of two kinds of in-jection condensers; they also have producedtwo arrangements of the surface type. Fig. 90is a sectional elevation of their condenser,having the tubes inclined athwart-ships. Theair pump is directly under the inner pistonrod, and derives its motion from an arm con-
is the latest example by Messrs. R. Napier andSons, for a pair of engines of 300 nominal horsepower collectively. The tubes are arrangedabove the pumps in one compartment, thesteam surrounding the tubes and the waterpassing through them. The circulating andair pumps are situated directly below the guide
nected to the same. The suction valves areinverted below the tubes, and those for thedischarge are at the side of the barrel abovethe same. The exhaust steam enters the tubesat the front end and passes to the back, thefinal discharge being into the chamber betweenthe pump and the tubes. Next, it will be