US11132A - Steam-engine regulator - Google Patents

Description

ANSON MERRIMAN, OF MIDDLETOIVN, CONNECTICUT. j

STEAM-ENGINE REGULATOR.

Specification of Letters Patent No. 11,132, dated June 20, 1854.

To all whom t concern:

Be it known that I, ANsoN MERRIMAN, of Middletowmcounty of Middlesex, and State of Connecticut, have invented a new and useful Improvement in Regulators for Steam Machinery; and I do hereby declare that the following is a full, clear, and exact description of the same,ireference being made to the annexed drawing, making a part of this speciiicatiomin whichvention as` applied. detail, and similar letters refer to similar parts throughout. j

The nature of my invention consists in an apparatus for lregulating the flow Iof steam j to the steam cylinder, and thereby'to `determine the velocit-y of the engine according to the work it is to` perform. `This I eifect by attaching to some convenient part of the engine an apparatus throughwhich a current of steam isfniade to flow, said steam being received lfrom and ,discharged `back again into the same reservoir. `The quantity of steam thus made to pass through the apparatus is to be so adjusted or rather measured that itshall alwaysbeara certain relation to the quantity entering the main cylinder of the engine, and of course tothe speed of the engine also,'so thatthe moment these relations are disturbed by any change 4in the engines velocity the `position of the `throttle `valve will be operated upon to re-` store the position the parts had previous to the disturbance, and thus maintain an average regularity `in the consumption of the` steam and in the work performed. i

By reference to `the accompanying drawings the construction and operation will be more readily understood.l

A represents the steam chest attached to a' steam engine. In someconvenient place the j regulating apparatus is attached; in Fig. I. It is represented asattached to the framing at one side of the cylinder.` The part seen at B, is a case containing a cylinder and piston,

piston rod, `and ejection and induction valves. The arrangement of these is seen in section Fig. II, where (a) is the cylinder (Z9) the injection valve chamber and "(0) the eduction valve chamber. The piston rod (CZ,) Fig. I passes through a stuffing boX` and is attached to a piston of usual construction.` The piston is made to play back and forth by the movement of the engine and is in its action and `effect similar to a double Fig. II is a section in acting pump receiving and discharging i i Thecompartment (g) is connected at the Figure I is an isometrical `view of my 1n-..

bottomwith the eduction valve chamber (c) l and has two other openings, one leading through (m) to the cylinder (E) and the other at (n) at the top, which is covered by a safety valve `The compartment has three openings one at (0) connecting it l with (E) `belowrthe piston, another at (p) connecting it withj(E) i above the piston,

and another to which a pipe (29') is attached connecting this` `compartment with the steam chest A. At (s) is another pipe leading from` the `stem chest to the injection valve chamber The piston rod is U pon the top of the piston rod (E) there is a weight which must `be sufficient to overcome the friction of the'piston and the piston rod, and cause it to fall sensitively at any diminutionin the pressure of the steam whichwmay flow into the cylinder E) beneath `the piston so that when an increased pressure is given to the steam below the piston `by means to be hereafter described, the piston may be forced up to any heightin the cylinder requisite for the proper opening of the throttle i valve. j j

The operation is as follows: All things being ready to start the engine, steam is allowed to flow into the regulator;` this `it does through the two pipes (S) and (79') filling all parts equally, and from the fact that the steam will fill all spaces alike there can be no circulation through the regulating machine.` j. The moment the engine is started, a circulation'takes place in consequence of the action of the piston in (a) .which being arranged as a double acting pump, commences drawing a current of steam through (S) and (b) and discharging by the eduction chamber (c) into (g) g: thence it flows through ou. un, 0). o), of) back into the steam chest whence it came.` Now the` velocityof `this current depends upon valve to the number of strokes of the pump, and the capacity of the cylinder, and as the pump is geared with the engine, its speed is regulated by the speed 'of the latter. To in crease the pressure of the steam under the piston in (E) to a degree beyond that above it which shall be suflicient to raise it or propel it along the cylinder, the cock (o) is turned to partially close the aperture (o) and of course the steam being permitted to flow no longer back to the steam chest as fast as it isvpropelled by the piston of the pump, is necessarily compressed and reacts upon the pump piston and also upon the piston in (E) thereby forcing up the latter, and thus turningthe shaft (t) on which is the throttle valve; now by graduating the degree of compression at. which the steam ought to be maintained in the chamber (E) with a certain speed of the engine, it is evident that so .long as the pressure of steam inthe boiler remains the same, and the load upon the engine also the same, there' will be no variation in the position of the throttle valve, because the artificial pressure as it may be termed, in the cylinder (E) will be also in a like ratio. But the moment there Vshall be any change in these conditions, viz any increase or diminution of the load upon the engine, then must the pressure in the cylinder (E) be changed and consequently its piston (E) be moved either up or down and thereby open or close the throttle valve as may be required. For instance, should the load be changed by suddenly diminish ing it, then would the speed of the engine and consequently the speed of the piston in (a) ybe increased, the increase of speed in the pump at once forcesin more steam than can'pas's through the aperture (o) and the compression is increased this at once throws up the pistonin (E) and closes the throttle the desired extent to cause a diminution of the speed of the engine back to the regulated rate. On the other hand if thereV shall be a check to the speed of the engine, then of course the artificial pressure produced in (E) is lessened because of the diminished supply of steam, and the descent of the piston following causing the throttle valve to be again opened. The safety valve at (n) is to allow of the discharge of steam in case through accident or carelessness the cock (m) or (0) should get closed too far to allow the steamv to pass through, and thus the risk of bursting the apparatus is obviated. The safety valve at (n) is so weighted or constructed as to hold the steam in chamber (9)' at greater pressure than in the boiler or steam chest lfrom whence it is taken 'and thereby producing a continuous pressure on the piston (E) holding it at the cornect point during the dead points of the engine.

. VFrom the above description itA will be seen that so long as the Idifference of the ar-r tiiicial pressure produced in (E) above and below the piston remains constant the throttle valve will be held stationary also. ln consequence, however, of the reciprocating motion of the pump there will be at each half stroke a momentary cessation in the flow of steam, yet the discharge through the aperture (o) is continuous; hence there will be a series of slight vibrations in the piston rod (E) at the turning of the engine upon its centers or dead points by reason ofthe diminution in the artificial pressure. These vibrations at each reciprocation of the engine have been a serious .obstacle to the use of all regulators in which the governing principle is dependent upon the regulation of a set discharge To obviate this is the object `of the combination of the chamber (g). and cock I effect uniformity in the pressure in the cylinder (E) at the time of the dead points, with that throughout the stroke by closing the cock (m) so as to retard the passage of the steam more than through (0) hence therey is a greater degree of compression produced in the chamber' (g) than iny (E) and it forms as it were a magazine or store house to the other to come vin use at the turning of the dead points of the engine for the steam will still continue to flow into (E) at those times and thereby maintaining the pressure will prevent the sudden vibrations which take place in all other machines depending upon a continuous character in the flow of same fluid, as known in various machines. The only way in whichthis oscillation is attempted to be obviated is by means of a slotcut 'in the connecting rod attached to the arm of the throttle valve; by such a contrivance the valve must be pinched up so tight as to sustain itself, and therefore more Y force is requisite to turn it. The valve is not acted on so soon as by my arrangement where the piston rod is connected so as t0 hold itirmly in all positions, for it can only be moved at the periods of alternate vibrations, and then it is accomplished by a series of taps or blows of the upper or lower end of the slot.

Another very serious diiiculty attendant upon the old mode is that should the pinch or friction which sustains the lever of the throttle valve be lessened, as is the case by wear, the weight of the arm suddenly -throws it open by dropping down as far source and acting on the piston (E) during the dead points of the engine.

2. I claim the aperture (m) chamber (g) and safety Avalve so Weighted as to hold the 5 steam at greater pressure than in the boiler in combination With the pump or pumps for forcing the steam into the said chamber (g) for forming a magazine to feed the cylinder (E) at the moment the engine is passing the dead points, and operating in 10 the `manner and for the purpose, substantially as described herein.

ANSON MERRIMAN. `In presence of- EBEN B. WHITE, JONATHAN BARNES.

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