US20894A - porter - Google Patents

Description

UNITED sTATEs PATENT oEEIoE.

C. T. PORTER, OF NEW YORK, N. Y.

GOVERNOR FOR STEAM-ENGINES.

Speccaton forming part of Letters Patent No. 20,894, dated July 13, 18'58'; Ressued June 21, 1859, No. 740.

To all whom it may concern:

Be it known that I, CHARLES T. PORTER, of the city, county, and State of New York, have invented certain new and useful Improvements in Centrifugal Governors for Steam-Engines and other Motors; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, making part of this specification, in which- Figure l is an elevation of a governor with my improvements. Fig. 2 is a horizontal section of the same below the balls and arms, exhibiting the method of applying the counterpoise.

Similar letters of reference denote like parts in both of the figures.

The object of my invention isto obtain 1n a governor of the centrifugal kind the two great requisites for a perfect governor, viz., lst, that it shall effect the whole of the movement necessary to enable it to open wide and close the regulating valve, or give the full range of variation which the regulator is capable of, with but an inappreciable variation in the speed of the engine or motor; and 2nd, that it shall commence to effect the said movement instantaneously upon the slightest variation of speed and effect it very rapidly. Neither of these requisites is possessed by the centrifugal governor as ordinarily applied, although, notwithstanding its serious defects, it is generally admitted to be, on the whole, superior to any of the various governors hitherto devised. To obtain these results I construct a centrifugal governor on any of the usual plans with balls and arms, but make it very much lighter, and instead of giving it only about the number of revolutions in a given time that would be due or natural to it, considered as a conical pendulum, as has hitherto been customary in the application of centrifugal governors, I.

drive it at a very much higher velocity, and apply to the slide of the governor, which connects it with the regulator, a counterpoise of a weight much greater than the aggregate weight of the balls and arms, and sufficient to balance, as nearly as possible, the great amount of centrifugal force developed by the revolution of the latter; and it is in the employment of a counterpoise so proportioned in weight, in combination vto the power with the arms and balls revolving vat a much higher velocity than would be natural to them considered as a conical pendulum, that my invention principally consists.

My invention also consists in so applying said counterpoise to the governor, that its effective load on the governor shall be lessened in such a degree, as the balls and arms of the latter expand, as to render itconstant, or as nearly so as desired, relatively of the governor to sustain it.

My invention further consists in the employment of the said counterpoise as a means of controlling the exact speed of the engine or motor.

A, is the frame of the governor.

B, is the main spindle arranged vertically and fitted to suitable bearings in the top and bottom of the frame A.

O, O, are the upper arms to which are secured the balls D, D; E, E, `are the lower arms; and F the slide.

G, is the lever which connects the slide F, with the throttle valve or other regulator employed; said lever working on a fulcrum c, and having its connection with the regulator at 6.

H, is the counterpoise applied to the lever G, the forked portions d, (Z, of which, carrying the pins c, c, which connect it with the slide F, are extended to a considerable length for the purpose of receiving the said counterpoise, which consists of a heavy block of metal. For the convenience of shifting this counterpoise upon the lever to vary its effective load on the governor, it has two slots made in it to receive the portions rZ, d, of the lever, and said slots con- `tain rollers e, e, whose axles are secured in the counterpoise, and which rest upon the portions d, (Z, of the lever.

I, is a small fixed standard which serves as a rest for the lever G, when the governor is not in operation, and also to carry two lixed pins j', f, to which the counterpoise H is connected by means of two radius rods g, g, the duty of which is, as the slide rises and carries the lever G with it, to draw the counterpoise nearer to the fulcrum a, of the lever and to sustain that portion of the weight of the counterpoise which is transferred to them as the inclination of the upper surfaces of (l, (l, is increased, and in both or either of these ways-according to the arrangement of said radius rodsto diminwith their action, and is the great cause of the sluggishness of the centrifugal governor as ordinarily applied; but upon the velocity with which the balls revolve; and as the force developed in the governor by any 'given percentage of variation in its speed increases as the square of the velocity, abundant force for this purpose is in this manner developed in very small balls. Larger balls would be not only unnecessary but disadvantageous, as the centrifugal force developed by their revolution at the speed desired would require to balance it a counterpoise of very great weight. The small balls, moveover, create but little friction by resistance to the force applied to quicken or retard their speed.

It is evident that the smaller the balls and the higher their velocity, the more trifling will be the friction occasioned, and the greater-by a rapidly multiplying ratiowill be the power developed by anyl given change in the motion of the engine or other motor to which the balls are aaplied. Yet it is necessary that the arms s ould be of considerable length, as the plane in which the center of percussion revolves must be at such a distance below the point of supen sion that the speed due to the governor, considered as a conical pendulum, would be moderate, and considerable action will be occasioned by slight changes in its velocity. It is not necessary, however, to establish any rule for the Weight of the governor or the length of its arms or the velocity of revolution; but I consider it desirable in no case to have the center of percussion revolve in a plane in which the speed due to the governor, regarded as a conical pendulum, would exceed fifty revolutions per minute, and if it be considerably lower it will be better, while the speed at which it is driven may be about siX times that velocity. The aggregate weight of the balls and arms should not eXceed five or six pounds. The counterpoise must be suiiicient to hold down the slide to confine the center of percussion of the governor between the highest and lowest desired planes of revolution when the governor revolves with the desired velocity. A range of about one inch for the slide F will be sufficient to enable the throttle valve or regulator to be moved through its entire range.

The operation is as follows :#I will first suppose the counterpoise to be fixed on its lever and its weight to be invariably the same. The centrifugal force of the governor is employed firstly in supporting the governor-balls and arms themselves, and secondly in lifting the counterpoise. After this, it has no other duty, except to overcome resistance from the friction of the joints it, i, j, which is the only obstacle to the action of the governor. This friction is so trifling, owing to the lightness of the balls and arms, that a very slight increase in the centrifugal force of the governor is suiiicient to overcome it and raise the counterpoise and slide F, and a corresponding diminution in centrifugal force leaves a portion of the weight of the counterpoise unsuspended, and allows the counterpoise and slide to descend; and as the centrifugal force of a revolving body is as the square of its velocity, the sensitiveness of the governor may be considered as very nearly in the same ratio, and hence a slight increase or diminution of the very high rate of velocity of the governor is sufficient to lift the counterpoise or cause it to fall instantly through the entire range of the slide F. But in a centrifugal governor operating as a conical pendulum, by a variation of the velocity of the motor similar'to that which is necessary to move the slide of my improved governor through the whole range, a scarcely perceptible increase of centrifugal force is produced, and hence the next reason of its slug gishness. The method commonly employed to counteract this sluggislmess is to make the balls very heavy; and in theory the sensitiveness of the governor is as the weight of the balls, but in practice their weight, if increased beyond a moderate amount, occasions more friction,by their own resistance to any force which would quicken or retard their motion, than the weight can overcome.

In order to make the operation of the counterpoise perfect, its weight or effective load on the governor must be constant, or nearly so, relatively to the power of the governor to sustain it; and as owing to the change of angle formed by the upper arms C, C, with the axis of the governor, a given amount of weight applied in the manner of the counterpoise has a greater effect in the upper planes of revolution of the balls, it becomes necessary to reduce the effective load of the counterpoise as the balls rise. rIhis may be effected in a variety of ways, as by transferring a portion of its weight to other bearings, or by moving it upon a lever as is done by the arms g, g, represented in l the purpose of fixing or adjusting the exact speed of the engine may be done in various Ways. 1When the counterpoise is applied in the manner represented in the drawing, provision maybe made for its adjustment by making the arms g, g, of variable length. To increase the velocity of the engine, the Weight of the effective load of the counterpoise must be increased, and vice versa. In cases Where it will never be required to vary the speed of the engine, the counterpoise, being made of proper Weight or applied so as to produce a proper effective Weight, serves permanently to iix and control the speed.

I-Iaving thus described my invention, I Will point out what I claim and desire to secure by Letters Patent, as follows l. In combination with arms and balls or their equivalents revolving at a much higher velocity than Would be natural to them considered as a conical pendulum, I claim the l employment of a counterpoise, applied substantially as described, and so proportioned in Weight as to balance, or nearly so, the centrifugal force developed by the revolution of said arms and balls or their equivalents.

2. I claim so applying the counterpoise to the governor lhat its eifective load shall be lessened as the governor rises or as the balls and arms thereof or their equivalents expand, for the purpose of rendering it constant, 0r as nearly so as desired, relatively to the power of the governor to sustain it.

3. I claim the employment of the counterpoise applied to the governor in any manner substantially as herein specified, as a means of fixing or adjusting the exact speed of the engine as herein described.

CHAS. T. PORTER. IVitnesses z O. D. MUNN, W. TUsoH.

[FIRST PRINTED 1911.]

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