DETAILS OF SCKEW ENGINES.

283

vaccum will be unimpaired. When the springis required to act, the lower or spindle valveis closed, and the annular or spring valveis as effective as an ordinary solid disc valve.The lever on the cover of the casing is mani-pulated at the starting platform, and the slotin the valve spindle ensures a certain action.To render this arrangement further obvious,the illustration, Fig. 131, is introduced.

Fig. 131.

BURGH S CYLINDER RELIEF VALVE.

This example shows the spindle valve closed,and in the place of a metal return valve, anindia-rubber disc is adopted, with an ordinaryguard, and a stuffing box to prevent a leakagearound the spindle. The springs in both ofthe examples can be adjusted by the set studs°u the cover.

Si act1 , v* ^ a-u-T

. BLOW-THROUGH VALVES.

To warm the cylinders and cause a vacuumin the condensers before starting the engines,supplementary valves are requisite. An ex-ample for this purpose is illustrated by Fig. 132.This is an ordinary disc valve with a spindleand lever, and the casing of a general formcompletes the apparatus.

It is obvious, on reflection, that steam, forthe purpose alluded to, should be admitted on

Fig. 132.

Wy/M

ORDINARY CYLINDER BLOW-THROUGH VALVE.

each side of the piston, after which into thecondenser, and to attain this a correspondingnumber of valves or pipes are requisite. To suitthis requisition Messrs. Penn have adopted thevalve and passage seating shown by Fig. 133.

Start! Fig. 133 .

y/y/yy^m.

MESSRS. Penn’s CYLINDER BLOW-THROUGH VALVE.

As the admission and exhaustion of the steaminto and from the cylinder is the main effect,an ordinary slide valve is preferred, by whichadoption a simple arrangement results. It

2 s 2

Avy dti>