THE

London

JOURNAL OF ARTS AND SCIENCES.

No. XXXVII.

Recent Patents.

TO JACOB PERKINS, of Fleet Street, in the City of London, Engineer, (in consequence of Communications made to him by a certain Foreigner residing abroad, and discoveries by himself) for the Invention of certain Improvements in Steam Engines.

[Sealed 6th June, 1823.]

THESE improvements are divided into five distinct subjects; the first of which is an improved rotatory-valve; the second a novel construction of throttle-valve; the third, a new application of a loaded valve; the fourth, a new arrangement of rings for metallic stuffing, and the fifth, a new condensing apparatus.

The object of the first mentioned improvement is to reduce that friction in a rotatory-valve of the ordinary construction which is caused by the action of the steam on the upper surface of the revolving plate. This is effected by substitut

pas

ing a revolving-plug for the plate, and opening the upper part of the plug to the atmosphere. In Plate I. fig. 1, is a horizontal view of the lower plate of the rotatory-valve, which is fixed, the passage a, being for the induction, and the sage b, for the eduction; c and d, are the openings leading into and out of the cylinder. Fig. 2, is a section of the improved valve, shewing the revolving-plug e e. Round this plug is a novel kind of metallic packing ff, consisting of rings, upon the plan to be hereafter described under the fourth improvement. These rings are pressed up to the top of the cavity, in which they act by small spiral springs, and are kept in contact with the sides by their own lateral pressure; thus the revolving-plug e e, is rendered steam-tight.

The rotatory motion of the plug is to be produced by means of a toothed-wheel upon its shaft taking into a suitable geer connected with the moving parts of the engine. The steam (in whatever way generated) passes by the channel a, of the fixed plate into the circular space h h, which circumscribes the plug; from thence it proceeds through several small holes into a channel i, which extends in a circular direction nearly half round within the plug; from this channel the steam passes down through the opening c, into the cylinder, and having there by its elasticity projected the piston forward, escapes from the cylinder through the opening d, into a channel k, which is also formed nearly half round the plug, as i. From this channel k, the steam passes through holes into the central space g, and thence through the eduction-passage b, to the condenser. Thus by the rotatory motion of the plug, the induction and eduction passages are alternately opened and closed. One of the principal advantages of this plug is, that by its peculiar construction the steam, which in the revolving plates now in use presses wholely on the upper surface, and thus creates an in

ased friction according to the force of the steam, is allowed

1

in the improved valve to pass from the induction-pipe round the outside of the plug filling the space h h. By this arrangement it will be seen that the steam from the eduction which occupies the channel k, and the central space g, will press the plug upwards; while the steam that is proceeding by the induction passages, will in the circular space h h, press the plug downwards, and thereby counteract or neutralise the excess of friction which would otherwise be created by an increase of force in the steam.

The second improvement (viz.) a new construction of valve to serve as a throttle-valve, consists in a method of opening and closing the steam-passage by means of the elasticity of a metallic plate or disk acted upon by a governor. Fig. 3, is a section of this valve; a, is a screw intended to be raised and depressed by the governor, which screw works in the plug 6 6. The bottom of this plug b, is made slightly concave in order to allow a thin flexible disk of steel cc, to lie in it :-d, is thep assage by which the steam proceeds from the boiler or generator, and e e, is a circular recess in the seat of the valve. The steam proceeding from the passage d, enters the recess e, and from thence passes through the passage f, to the working cylinder. But when the action of the engine is too rapid, the descent of the screw-plug b, (which rises or falls according to the velocity of the governor) will press the flexible disk c, down upon the aperture of the steam passage a, and partially, if not entirely, closes it.

The third improvement, a new application of a loaded valve, is shewn at fig. 4, in which a, represents part of a generator with its loaded valve, as described in Mr. Perkins's patent of December, 1822, (see Vol. VI. page 1.) bb, is the pipe extending from the generator to the working cylinder c. The passage of this pipe is intercepted by the improved valve at d. The construction of the passages are sufficiently shewn by the sectional part of the figure :—e is

the slide-rod forced upwards by the loaded lever f; this rod must slide free in its tube, and allow water to pass between; the steam above pressing upon the water forces it down, and thereby closes a conical leather valve, which is made to encompass the lower part of the rod, and thus the valve is kept steam-tight, the length of the tube keeping the water at bottom so cool as not to injure the leather. By this arrangement the steam evolved from the generator must, before it can pass into the cylinder, force down the sliding-rod which forms the loaded valve. This resistance or interruption of the steam, previous to its entering the working cylinder, is the substance of the improvement proposed under the third head. It is stated that it will be proper here to observe "that the application of a loaded valve interposed between the steam-chamber of an ordinary steam-boiler and the cylinder, will answer the same purpose; the third improvement therefore does not embrace any novelty that may be in the particular loaded valve shewn in the drawing."

The fourth improvement (viz.) a new arrangement of rings for a metallic packing, consists of an elastic ring between two non-elastic rings, the opening of the first being covered by the solid parts of the second, the passage of the steam being thereby effectually intercepted. Fig. 5, is a section of the piston with the improved metallic packing, and fig. 6. is an external view of the same; a, is an elastic ring, such as is commonly used for this purpose, the plan or horizontal view of which is shewn at fig. 7; it is cut open at the part marked b. In order to prevent the escape of steam at the opening two non-elastic rings c c, (shewn also in the horizontal view fig. 8,) are placed, one above, the other below the elastic ring a, and are kept in their positions by guide-pins e, extending from the solid piston, and are pressed to that side of the piston where the elastic ring is opened by

springs. The effect of this contrivance is, that the elastic ring a, filling the circumference of the cylinder in which it works, prevents the passage of the steam except at the open part b; the excentricity however of the solid rings c c, is contrived, so that when the piston is put into the cylinder they lay close and cover the opening of the elastic ring, thereby rende ring the whole a perfectly steam-tight packing. Reversing the parts would produce a stuffing suited for a piston-rod.

The fifth improvement, a new condensing apparatus, is shewn at fig 9:-a, is a generator with its loaded valve, as before-mentioned: b, is an induction-pipe leading from the generator to the cylinder c.-d, is an eduction-pipe, which passes through the tube e, and thence into a reservoir f; this reservoir feeds the forcing-pump g, and by means of which the water is forced through the pipe h, into the tube e, and thence through the pipe i, into the generator. With this apparatus the operation of condensing is performed in the following manner.—

The steam from the generator a, passes by the inductionpipe b, into the cylinder c, at a very high temperature, and having exerted its power upon the piston leaves the cylinder at nearly the same temperature by the eduction-piped; while the steam is passing through that part of the pipe which is circumscribed by the tube e, cold water from the reservoir ƒ, is pumped through the tube in a contrary direction, by means of the forcing-pump g, the effect of which will be that the steam in the eduction-pipe d, will be condensed, and will run in the form of water into the reservoir f, while the cold water by passing through the tube e, becomes heated, and in that state proceeds out of the tube by the pipe i, into the generator.

The points claimed under this patent are a "rotatory valve improved as aforesaid, and also a valve to serve as a