US222802A - Improvement in air-compressors - Google Patents

Description

W. P. TATHAM, Air-Compressor.

No. 222,802. Patented Dec. 23,1879.

Wily: 68893. In vezz Z01".

N-FETERS, PNOTO-LITHOGRAPHER WASH NGTON, n C.

'rrn

WILLIAM P. TATHAM, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN AlR-COMPRE SSORS.

Specification forming-part of Letters Patent No. 222,802, dated December 23, 1879; application filed November 3, 1879. 4

To all whom it may concern Be it known that I, WILLIAM P. TATHAM, of the city and county of Philadelphia, in the State of Pennsylvania, have invented a certain new and useful Improvement in Air Oompressors, of which improvement the following is a specification.

The object of my invention is to provide, in an air compressing apparatus operated by the pressure of steam or other expansive fluid, suitable means for economically and advantageously applying and utilizing the operating medium by proportionately adapting the decreasing force thereof when acting expansively to the increasing resistance of the air under and during compression.

To this end myimprovement consists in the combination ofa steam-cylinder and its reciproeating piston, a double-armed rock-shaft or bellcrank vibrated by said piston, and an air-cylinder havinga piston which is reciprocated by the vibrating rock-shaft, the steam and air pistons beingy respectively, connected to arms on the rock-shaft set at an angle of about ninety degrees apart, all as hereinafter more fully set forth.

In the accompanying drawings, Figure l is a sectional plan View of one form of an aircompressor embodying myimprovement; Fig. 2, a side view, in elevation, of the same; and Fig. 3, a sectional plan view, showing another form of the application of my improvement.

The distinctive feature of my improvement consists in applying the operative power to the resistance to be overcome through the intermediation of two vibrating arms, the relation of which, in position one to tlm other, is

such that the energy of the steam from the beginning to the end of the stroke of the operating-piston is accompanied by an increasing leverage of the arm to which it is connected, and a corresponding decrease of leverage of the arm to which the compressing-piston is connectedthat is to say, as the first or power arm moves from near its dead-point to its point of greatest leverage and power the second or resistance arm correspondingly moves from its point of greatest to its point of least leverage and resistance. The application of this principle of operation may be made in various different forms without departing from the spirit of my invention, two of into which the rod a is prolonged, and within which a piston, c, is secured upon it. Steam and air pistons a and c are similarly secured upon a rod, a in the cylinders A and C, respectively, and the piston-rods a and a carry upon their outer ends cross-heads a a which slide in guides a a parallel to the center lines of their rods. mounted in bearings on the bed-plate B, perpendicularly thereto and midway between the longitudinal center lines of the cylinders A and A, has secured upon it a bell-crank composed of two arms, (I and d, the center lines of which form an angle of about ninety degrees.

The cross-head a of the cylinder-A is coupled by a connectingrod, E, to 'a crank-pin on the arm at of the rock-shaft D, and the cross-head a of the cylinder A is similarly coupled by a connecting-rod, E, to a crank-pin on the arm d. The length of the connecting-rods E and E is such that when the piston aof the cylinderA is at the extremity of its stroke farthest from the rock-shaft, the crank-pin of the arm d, to which said piston is connected, will stand at a point in its are of vibration ten degrees, or thereabout, from the longitudinal center line between the cylinders A and A, on the side of said line adjacent to the cylinder A, and the full stroke of the piston will vibrate the arm (1 through an arc of about twenty degrees less than the angle between the arms. The corresponding position of the piston a of the cylinder A will be atthe opposite extremity of its stroke, and, at the completion of the traverse of its arm (1 through an are, as above described, the crank-pin of said arm will oc- A rock-shaft, D, which is cupy a position ten degrees from the center line between the cylinders on the side adjacent to the cylinder A The length of stroke may be exactly regulated by suitable stops; or, if preferred, the rock-shaft may carry an additional arm, which is to be coupled by a connecting-rod to a crank and small fly'wheel.

In the operation of my improvements the admission of steam behind the piston a of the c ylinderA effects the outward movement of said piston and the accompanying withdrawing stroke of the attached piston c of the aircylinder 0. The vibrating arm d, to which the piston-rod a is connected, continually increases its leverage during the stroke, and the force applied to the piston a during its outward stroke, acting through the arms 01 and d and connecting-rod E upon the piston-rod a, effects the inward movement of the steam-piston a and the accompanying forcing or compressing stroke of the piston c of the air-cylinder O, the resistance-leverage of the connected arm d, by which said piston c is forced in ward, continually decreasing from the beginnin g to the end of the stroke. Conversely the outward movement of the piston a effects in a similar manner the inward movement of the piston a and the forcing stroke of the air-piston c.

Fig. 3 illustrates the application of my improvement to a doubleactin g steam-cylinder, A, operating two single-acting air-cylinders, O 0, two rock-shafts, D, each having double arms 01 and d, as above set forth, being provided, and the operation being similar to that of the sin gle actin g cylinders before described, the forcing stroke of each of the air-pistons c and 0 being effected, under the same relation of moving parts, by the movement of the steam-piston a in the opposite direction.

The construction shown in Figs. 1 and 2 may be modified by prolonging each of the steamcylinders, providing it with an air-piston and air-valves toward its delivery end, and dispensing with the two separate air-cylinders, two cylinders, each of which performs the function of an air and a steam cylinder, being employed in lieu of four, as in Figs. 1 and 2. In such case a hollow rod is employed for each steampiston, and the air-piston rod of each cylinder passes through the steam-piston and its hollow rod, and is coupled by a connecting-rod to an arm on the rock-shaft, set at an angle of about ninety degrees with that of the steampiston, four rock-arms, one for each steam and each air piston, being employed.

The steam and the air piston of each cylinder move in the same direction, but at unequal rates of speed, and the inward stroke made by the steam-piston of one cylinder effects the compressing stroke of its own air-piston and the withdrawing stroke of the steam and air pistons of the opposite cylinder under conditions of power and resistance leverage similar to those which obtain in each of the two arrangements of parts hereinbefore described.

It will be obvious that the changes of location and number of the parts in the several applications of my improvement herein described and shown are matters of constructive detail simply, and involve no Variation in either case from the fundamental principle of my invention hereinbefore set forth 5 and while a duplication of parts is required to constitute a double-acting compressor, the operation of compression is performed at each stroke by the combined action of one steam and one air piston and the arms to which said pistons are respectively connected.

I do not limit myself to the particular relative location and arrangement herein shown and described, as the same may be greatly varied within my invention.

I claim as my invention and desire to secure by Letters Patent-- The combination, in an air-compressor, of a steam and an air piston, each reciprocating within a cylinder, and a double-armed rockshaft or bell-crank having its arms connected, respectively, with the rods of the steam and of the air piston, these members being combined for joint operation to effect the compression of the airunder a decreasing leverage of the rockshaft arm of the air-piston and a correspondingly-increasing leverage of the arm of the steam-piston, substantially as set forth.

W. l. TATHAM.

Images