US358598A

US358598A - Steam engine

Info

Publication number: US358598A
Authority: US
Publication date: 1887-03-01
Anticipated expiration: 1904-03-01

Description

'3 Sheets-Sheet 2.

(No Model.)

T. L. DENNIS. STEAM ENGINE.

(80 Model.)

' I 3 Sheets-Sheet 8. T. L. DENNIS. STEAM ENGINE.

Patented Mar. 1,1887,

'UNITED STATES PATENT Fri-on THOMAS L. DENNIS, OF SOMERVILLE, ASSIGNOR OF ONE HALF TO LABAN DENNIS, OF NEWARK, NEW JERSEY.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 358,598, dated March 1, 1887.

Serial No. 208,391. (No model.)

To all whom it may concern:

Be it known that I, THOMAS L. DENNIS, a citizen of the United States, residing in Somerville, Somerset county, New Jersey, have invented certain new and useful Improvements in Steam-Engine Out-Offs, fully described and represented in the following specification, and the accompanying drawings,forming a part of the same.

This invention relates to a device in which separate slide-valves are fitted to the induction-ports and are operated by detachable tappets, which are controlled by the governor; and the invention consists partly in the construction and arrangement of the slide-valves and cylinder-ports, and partly in the construc tion of the cut-off mechanism, all substantially as hereinafter set forth.

In the drawings, Figure 1 is a side elevation of an engine provided with my improvement. Fig. 2 is a plan of part of the cylinder and cutoff mechanism on a larger scale, the parts being shown in section, where hatched, at the center line of the cylinder, with a false valve seat. Fig. 3 is a side elevation of the same with the steam-chest cover removed. Fig. 4 is a plan of the valve-seat. Fig. 5 is a view of the face of the valve. Fig. 6 is a side view of one of the valves, and Fig. 7 is a cross-section of the same with part of the cylinder and the false valveseat on line a; a: in Fig. 5.

A is the bed of the engine; B, the steamcylinder, and G the connecting rod to the crank O.

D is the crank-shaft carrying an eccentric, D, which serves, by the use of any valve-cutoff mechanism, to operate two separate slidevalves independently and to out OK the steam at any desired point in the stroke.

The valve-seat E is provided with two in-- duction-ports, a a, and with two eductionports, I) I), each opening into the seat adjacent to one of the ports a or a. The seat is raised above the steam-chest seat S, so that the steamvalves may receive steam from the edges of the seat, and the ports b b are united in an exhaust-outlet, b and are each connected alternately with the adjacent inductionport by the arch c in a flat D-valve, V.

. The steam-chest T is fitted to the seat S and provided with a cover, T, and a stuffing-box for the valve-rod.

The valves V are each provided with a cover, d, which forms a chamber, e over the back .of the valve for connecting the ports a a with the steam-supply which enters the chest by pipe U,or at any convenient point. The chamber has several openings through the valveface to receive the steam from the chest and to lead it into the induction-port, the opening 6 corresponding 'in size and communicating with the port a or a, and the openings 6, formed one at each side of the arch a, communicating with ports 8, formed in the surface of the valve-seat and receiving steam from the interior of the chest by passages 8. These passages are shown in Fig. 7 as opened into the edges of the valve-seat, which is made narrower than the lateral walls of the chest, to afford the steam access thereto.

The openings 6 are shown in the drawings about equal in area to the passage 6, and the steam passes upward through the former and downward through the latter. Its pressure upon the valve may thus be substantially balanced,and the frictional resistance of the valve may be-diminished or regulated in any desired degree.

These valves are provided with separate concentric valve rods m and n, the former passing through the latter, and each being provided beyond the stuffing-box S with a dog, it, by which it is independently moved. Such movement is effected by the regular reciprocating motion of a slide, G, which is actuated by a connection, D to the eccentric D. The slide is furnished with two tappets, q, pivoted at its middle and projected toward the dogs 70, and with two lugs, o, for positively shifting the valve to open the exhaust at the end of each stroke. The tappets and lugs project from the slide toward the valve-rods and their attached dogs, and shift the valves in either direction when engaged therewith. The tappets are also furnished with inclined arms q, projecting from the opposite side of the slide toward a cutoff stop, f, which is actuated by the governor, and serves to detach the tappets from the dogs at the required point in the stroke.

The governor shown at h in Fig. l is represented as mounted upon the guides p, which sustain the slide G, and the rising of the governor-balls y, when the engine increases in speed, serves to press the stop f toward the slide and to intercept the inclined arms q earlier in the stroke. The contact of the arm with the stop operates to move the arm and tappet upon their common pivot and to withdraw the tappet from the dog, as shown in Fig. 3. When the dog is thus released from the tappet, the valve -rod is immediately shifted to close the valve by means of a spring, t, applied to the rod between the guide 2) and the dog.

The valve connected with the tubular valverod a is shown in Fig. 3 thus shifted, the amount of movement effected by the spring being indicated by the projection of the tappet beyond the shoulder with which it was engaged upon the top of the dog.

The springs are adjusted to move the valve freely until the induction-port of the cylinder is closed, as shown in the valve connected with the rod m, the unbalanced pressure upon the back of the valve or its cover then serving to increase the frictional resistance of the valve and to prevent its shifting still farther into a position where the exhaust would be opened. The further movement required to open the exhaust is eiTect-ed positively at the end of each stroke by the lug 0, the tappet engaging with one side of the dog when the lug presses upon the other, as shown in the dog upon the valverod m.

The slide G is shown at the extreme lefthand end of its stroke with one valve (that on the rod in) wholly shifted by the lug 0, and the other (that on the rod n) closing over the iuduction-port ct by the action of the spring t. A stuffing-box, n, is applied to the end of the hollow valve rod n, to prevent leakage around the rod, and the dogs are secured adjustably upon the valverods, as by nuts o, to permit the adjustment of the valves.

It is obvious that with this construction the point of cut-off may be varied indefinitely by the automatic action of the governor, and as the valves, by the construction of the valvecover d and its openings 0 e, may be very nearly balanced upon the seat S, the movement of the dogs and the tappets may be effected with very little strain upon the latter, and the entire mechanism operate as efl'ectively as the valve-gearing commonly applied to a Corliss engine. My invention therefore affords, by the combination of the balanced D-valves and the independent tappet-connections with the slide and eccentric, a substantial equivalent at much less expense for the hi ghlyapproved Corliss valve-gearing.

A special advantage in my construction is that the valve mechanism affording these advantages may be readily substituted for that of any other slide-valve and eccentric upon an engine unprovided with a cut-off. In such case the ordinary three-ported valve-seat may be readily converted into a four-ported seat, such as is required for my independent D- valves by applying a false valve-seat. Such a construction is shown, for illustration, in Fig. 2, where the seat S is shown provided upon its outer face with the four ports to operate with my improved valves, and upon its inner face with three ports to fit those upon the original cylinder-seat S.

It will be noticed that my invention differs from others in which two valves are operated over separate induction-ports, as a a, in moving toward one another independently and alternately when the valve opens at the commencement of the stroke to admit steam to the cylinder. Such a method of operation arises from the particular construction and arrangement of the tappets and the lugs which are affixed to the eccentric slide G to actuate the valves, and which thus efl'ect substantially the same result as the tappets and cut-oif-release mechanism employed in the Corliss Valvemotion.

My invention may be cheaply applied to either new or old engines, and effects a very material saving in the consumption of steam when applied to the latter.

I am aware that it is not new to balance a slide-valve by making a chamber over the back and openings in the face, as shown herein, and that two independent valves have been actuated by concentric valve-rods similar to mine. I do not therefore claim either of such constructions, broadly, but have shown the advantage of combining the balanced D-valve of simple construction with the particular class of cut-off mechanism which I employ, and which would not be so durable or operative with a heavily-loaded slide-valve.

Having thus set forth my invention, what I claim, and desire to secure by Letters Patent, 1s-

1. The combination, with a cylinder valveseat, S, having two induction and two eduction ports, arranged as described, of two D- valves provided with concentric valve-rods, and dogs applied to such valve-rods and actuated by detachable connections, as tappets q, to a reciprocating slide G, substantially as herein set forth.

2. The combination, with a cylinder valveseat, S, having two induction and two eduction ports, arranged as described, of two D- valves provided with concentric valve-rods, and dogs applied to such valve-rods and actuated by an eccentric slide, G, provided with lugs 0, and tappets q, having arms q, actuated by a governor-stop, substantially as herein set forth.

3. The combination, with the valve mechanism constructed substantially as herein described, of a detachable valve-seat provided with four ports upon one side terminating in three po r'tsupen the opposite side, adapted to of the valve, communicating with the inletfit a three-ported valve-seat, as and for the ports a a andthe ports s, as and for the purpurpose set forth. pose set forth.

4. The combination, witha cylinder valve- Intestimony whereof I have hereun set 5 seat, S, having two induction-ports, a a, and my hand in the presence of two s'ubscnbing 15 two eduction-ports, bb,arranged as described, witnesses.

of lateral passages s, communicating with the THOMAS L. DEN N IS. steam-chest and with the ports 8 upon the withessesz. valve-seat, and two D-valves having each a THOS. S. CRANE,

10 cover, (1, forming a chamber, a, over the back HENRY J. MILLER,