I. TUE LATEST TYPES OF STATIONARY RECIPROCATING STEAM-ENGINES.—The Woodbury Engine is shown in perspective in Fig. 1. Fig. 2 is a vertical section through the cylinder and valve. Fig. 3 is a horizontal section through the steam-chest above the top of the valve. Fig. 4 shows the steam-chest with cover removed, exhibiting the back of the relief-plate and wedge. Fig. 5 is an end view of the relief-plate and wedge. Fig. 6 is an enlarged view of the upper adjusting screw; and Fig. 7 is a back view of the valve.
Referring to Fig. 2, steam-pressure is eliminated from the valve A by the relief-plate B on the back, which is supported against steam-pressure at top and bottom by a forked or double wedge C, whose length is about equal to that of the relief-plate. It is obvious that a longitudinal movement of the wedges inward will force the relief-plate away from the valve, and the outward movement of the wedges will let it down toward the valve. The movement of the wedges, and consequent adjustment of relief-plate, is accomplished by the two adjusting screws / /' (Fig. 3). whk'h fit loosely through the cross-piece of wedge and are tapped into the relief-plate. The collars which form part of adjusting screws, arc notched on their periphe ries, as shown in Fig. 6, and a notch a is made on the wedge opposite each screw. The collar has 100 notches. and therefore admits of a defi nite degree of adjustment. The adjusting screw has 10 threads per in.. and the taper of wedges is 1 in. in 10. One notch on the collar, therefore, representing of a turn, moves the wedge lengthwise iala of an in., and the relief-plate to ward or from the valve of an in., corre sponding to of an in. on each face of the valve. The passage k at the bottom of the chest allows a circulation of steam under the ledge. in suring equal temperatures for ledges i i'. The screw which is operated from the outside by the handle E, is also used as a means of moving the wedges inward and throwing off the relief plate ; but the plate can not be let down farther than the adjustment allows, as the wedges can not be drawn back farther than the collars m of screws (Fig. 6). The amount of inward ment is regulated by the screw f (Fig. 4) which forms the stop for the inward movement of the wedges. This screw taps into the relief
plate, and against its head the cross-pieee of the wedge strikes. When the handle E is turned to the left as far as it will go, the wedges are hack against the collars and are in proper work ing position; when, on the contrary, the handle is moved to the right, the screw which works through the stuffing-box forces the wedges inward and throws off the relief-plate. About one half turn of the handle is all that is necessary. The purpose of this handle and screw is to afford a means of separating the valve-faces from seats in ease they tend to adhere together after engine has been standing for some time. The valve A (Fig. 8) besides taking steam at the ends, has supplemental admission ports a a' (Fig. which are connected at top and bottom by passages b 11. The steam is entering cylinder-port directly past. the end of the valve, ana also through the cavity in the relief-plate into port a'. Steam is at the same time entering supplemental port a at opposite end at points, and traveling through the horizon tal passages into port u: and cylinder-port. The telniksion, therefore, takes place at torn• points at the same time, and, as the ports are very large, the nearest approach to boiler-pressure is reached. and the usual loss boiler and cylinder reduced. A double exhaust is also used.
Fig. 8 shows the method of atinehing the counter•-weight,d disks to the cranks for the purpose of balancing the reciprocating parts.
shows the ct•oss-beup1 in top and end view. Ilse piston-rod being. in section.
The constrnet ion of the main connect iug-rod is shown in Fig. 10.
Soreetx •Straight - Engine, ],nips by Sweet's' Mann factoring Syracase, is shown in Fig's. 11 to '2•? The frame consists of two straight arms running from t be cylinder to the main bearings, with the balance-wheels between, the whole resting on three self-adjusting points of support. All strains go in straight lines ; all boundary-lines are straight, ending in curves ; all cross-sections of stationary parts are rectangular, with rounded corners; and all moving arms and levers are double convex, wide and thin, with the longest axis in the direc tion of the greatest strain. The frame is cast in one piece with the cylinder and steam-chests.