OSCILLATING ENGINES.

Now the action of the piston and valves asarranged in the examples alluded to beingobvious by noticing the illustrations, the de-scription just presented may seem unnecessary.It must be added, however, as a cause, thatalthough the remarks in question are in con-nection with the prior examples, they refercomparatively to the arrangement next to he

Fig. 44.

burgh’s improved injection condenser and air pump.

alluded to, represented by Fig. 44, In thisexample the condenser is above the pump, thebottom of the former being nearly level withthe exhaust opening in the trunnion. Thesuction valves are inverted, and the dischargevalves laterally situated directly below theformer. The piston is of a peculiar section,recessed to suit the requirements of adjust-

199

ment, and effecting an almost perfect dischargefrom the space directly below the condenser.The piston rod passes through the bottom ofthe condenser, in which latter compartment aguide channel is formed. The discharge cham-ber and air vessel are ot the ordinary kind,with the feed water pipe shown connected tothe underside. The injection valve passageand rose-pipe are near the roof of thecondenser, a certain height above thetrunnion openings. The cock and valvebelow the trunnion openings, are for thepurpose of permitting a discharge of anycondensed steam that may accumulate in theexhaust steam passage at the front of thecondenser.

The sectional elevation having been thusfar alluded to, attention must now he directedto the plan. To render this view practicalas well as conclusive, one half is shown insection and the other complete.

This form of condenser is especially adaptedto admit ample space for adjusting and re-newing the packings of the exhaust trunnionstuffing boxes, an advantage only to be appre-ciated by those who are acquainted with thecramped space generally allotted for thosepurposes. Access to the entire set of valvesis attained by doors suitably placed—therepresentation of which is seen in bothviews.

Next to be considered is the actual gainby the adoption of the arrangement underpresent notice over those previously alludedto as the common practice. It will beremembered it has been stated that, withthe usual arrangements, on the piston risingthe foot valves open. Now in the present