US529545A - Direct-acting engine - Google Patents

Description

(No ModeL) 0. P. DEANE. DIRECT ACTING ENGINE.

No. 529,545. Patented Nov. 20, 1894.

" nrrnn dramas PATENT must CHARLES P. DEANE, OF SPRINGFIELD, ASSIGNOR TO THE DEANE STEAM PUMP COMPANY, OF HOLYOKE, MASSACHUSETTS.

DIRECT-=ACTING ENGINE.

SPECIFICATION forming part of Letters Patent No. 529,545, dated November 20, 1894. Application filed July 9,1394. Serial No. 516,911. (No model.)

To aZZ whom, it may concern:

Be it known that 1, CHARLES P. DEANE, of Springfield, county of Hampden, State of Massachusetts, have invented an Improvement in Direct-Acting Engines, of which the follow ing description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

Thisinvention relates to that class of steam engines wherein the power is applied directly to the load without the intervention of a rotating crank, as in drills, pile drivers, air and gas compressors, pumps and other similar machines, and it has for its object the production of means for controlling the length of the stroke of the piston, so that the longest stroke consistent with safety and proper action of the apparatus can be maintained under varying conditions. As is well known, in such machines a closed pocket or cushion is formed at the end of the cylinder, between its head and the piston, and the length of the stroke, with the pocket or cushion of a fixed length, will vary greatly under changes of load, steam pressure, back pressure, speed or other condition, notwithstanding any adj ustment of the area of the relief port. For example-if a certain length of the cushion is proper for a certain load and speed, an increase of that load at the same speed will shorten the stroke, or if the load remains the same, an increase of speed will lengthen the stroke. In either case the length of the stroke will be governed by the pressure of the steam subjected to compression in the pocket or cushion.

As machines of the class referred to are subject to duty with one or more factors necessarily variable, either from change of condition under which a given machine should operate, or from a difference of conditions under which similarly constructed machines should operate, some means of adjustment other than that obtained by changing the area of the relief port becomes not only desirable but necessary.

Myinvention consists, in a direct acting ongine, wherein the power is applied directly to the load, of the main steam cylinder, having induction and eduction ports, a piston in said main cylinder adapted to close the eduction ports at fixed points in its stroke, and an auxiliary eduction port communicating with the main eduction port and adapted to be completely closed by the piston at a determinate point in its stroke, combined with means to regulate such point of closure by altering the position of its cut-oft edge, substantially as will be described.

Other features of my invention will be hereinafter described and particularly pointed out in the claims.

Figure 1 is a longitudinal sectional view of a steam cylinder embodying my invention, showing also the piston and piston rod by means of which the power is applied to the required load. Fig. 2 is a transverse sectional View of the cylinder taken on the line a:0c, Fig. 1, looking toward the right. Fig. 3 represents in section one end of the cylinder with the adjusting and regulating mechanism omitted, and Fig. 4 is a perspective view on an enlarged scale and partly in section, of the regulating and adjusting devices.

The main steam cylinder A, induction ports a, a, and eduction ports I), b, the slide valve B, steam chest B, steam piston P, and pistonrod P, which is connected directly to the load, (not shown,) are and may be of usual and well known construction.

In Fig.1 the piston P is supposed to be traveling in the direction of the arrow and nearing the end of its stroke, communication being established by the valve B between the main exhaust E and the eduction port 6. The induction port a is closed by the valve and the induction port a is open, the said valve being moved by any suitable mechanism. Not shown.

It will be readily understood that the eduction port 5 will be positively closed by the piston P after it has moved a short'distance to the right, cutting off further escape of steam from the cylinder, whether communication between said port and the exhaust outlet E be established or not. Such positive closure of the eduction port always takes place at a fixed point in the piston stroke and is determined by the position of the cut-off edge of the said port. The steam so confined in the pocket between the cylinder head and the piston forms the cushion for the latter.

When absolute closure of the eduction port takes place, if the imprisoned steam is insufficient to arrest the motion of the reciprocating parts by its compression during the remainder of the stroke, the piston will come in direct contact with the cylinder head with more or less violence, depending upon its speed and momentum. On the contrary, if the imprisoned steam is greater than is necessary to stop by its compression the reciprocating parts at the proper point in the stroke of the piston, the stroke will be shortened, causing thereby a reduction of the work performed, and a loss of steam on account of the excessive clearance which must be filled on the readmission of steam to that end of the cylinder. It is therefore obvious that the position of the eduction port determines the amount of steam imprisoned, irrespective of the size of the port or any device for throttling it. With different conditions the position of the said port will vary, and as the position cannot be accurately determined by calculation it is now the practice to make an experimental cylinder, with the eduction port given conditions.

located as nearly in the right place as may be, and then to determine by means of indicator cards the difierence between the actual position and the correct position under the That being determined another cylinder is made, with the eduction port correctly placed, the experimental cylinder of course having no further value. Such practice is expensive, evidently, and awkward, but up to the present time it has been the only way in which a satisfactory operation for such engines has been attainable, particularlyin the case of direct acting pumps having a very short stroke with a quick motion.

In order to readily adapt the motion of the piston to the varying conditions which arise, so that a particular apparatus is not restricted to an exact set of conditions, and without having recourse to the hereinbefore described usual practice, I have provided means for changing the position of the cut-off edge of the eduction port, whereby the adjustment may be made from the exterior of the cylinder, and as herein illustrated I have provided, preferably in each end of the main steam cylinder a separate opening or portv having a variable cut-0E edge.

The auxiliary eduction or cushion controlling port 0, formed, as herein shown, by recessing the inner wall of the cylinder, communicates with the usual eduction port by means of the passage 0. See Figs. 1 to 3.

A piece 01, see Figs. 1, 2, and at, is fitted steam tight in the recess 0, and is movable therein to form a portion of the wall of the cylinder, said piece 01 being adjustable in the recess so as to vary the position of the cut-oh edge of the auxiliary port, and consequently to change the length of the pocket at the end of the cylinder, when said port is closed by the passage of the piston.

The position of the piece 01, and thereby the time of absolute cutoff, is controlled by an actuator, herein shown as a threaded rotatable rod or stem 01, one end of which is extended through the cylinder head A and connected to the said piece 01, the piece d having, as shown in Fig. 2, an opening (1 therein to receive the threaded end of the rod or stem 01. The rod or stem is provided with a suitable flange d to enter a suitable recess in a stuffing box a, and the end of the rod projecting beyond the stuffing box is provided with means whereby it may be rotated. The

movement of the piece (1, by 'rotationof the.

rod d, regulates the position of the cut-off edge of the port and causes absolute and positive cut-off by the piston to take place earlier or later in its stroke, and so increases or decreases the length of the cushion pocket as finally closed by the passage of the piston, and such final closure may be either simultaneously with the closure of the regular eduction port or later.

It will be obvious from the foregoing, that within the prescribed limits, only a proper quantity of steam of a given pressure can be retained as a cushion to arrest, by its compression,the motion of the reciprocating parts under the conditions of load and speed resulting from the required duty.

Increase of load or speed demands a larger quantity, and decrease of load or speed a smaller quantity of steam with the same pressure for the exhaust.

An increased pressure on the exhaust necessitates a less quantity, or a decreased pressure a greater quantity of steam, with the same load and speed.

While I have herein shown an undercut recess c and a piece 01 correspondingly shaped in cross-section, my invention is not restricted thereto, as it is obvious that any shaped recess may be used which will hold the piece in place and permit longitudinal movement thereof and the size of the port is of practically no importance.

My invention is not restricted to the particular devices shown for adjusting the variable cut-ofi edge of the auxiliary eduction port, nor to the exact location of such port, as modifications and changes may be made according to circumstances without departing from the spirit of my invention.

I claim 1. In a direct'acting engine, wherein the power is applied directly to the load, the main steam cylinder having induction and eduction ports, a piston in said main cylinder adapted to close the eduction ports at fixed points in its stroke, and an auxiliary eduction port communicating with the main eduction port and adapted to be completely closed by the piston at a determinate point in its stroke, combined with means to regulate such port, so as to regulate the amount of cushion point of closure by altering the position of its team imprisoned in the ends of the cylinder, cut-off edge, substantially as described. ubstantially as described.

2. In a steam cylinder having induction In testimony whereof I have signed my 5 and eduction ports, an independent eduction name to this specification in the presence of r5 port having a movable cut-off edge and two subscribing Witnesses.

adapted to be absolutely closed by the piston CHARLES P. DEANE. in its stroke, and the piston movable in the Witnesses: cylinder, combined with means to vary the W. J. COOPER,

IO position of the cut-off edge of said eduction F. W. TINKER.

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