US678570A - Motor. - Google Patents

Description

Patented July l6, I901. W. A. JONES.

M 0 T 0 R.

( Application filed Oct. 22, 1900.)

2 Shasta-Sheet I.

(No Model.)

I has M MM a Z I! J2 0% i wx IN VENTOH A TTORIVE Y5 Patented July 16, l90l.

W. A. JONES.

MOTOR.

J J I I PATET 11 error.

WVILLIAM ANTHONY JONES, OF WEST BRIGHTON, NElV YORK.

MOTOR.

SEEGIFIGATION forming part of Letters Patent N0. 678,570, dated July 16, 1901.

Application filed October 22, 1900. Serial No. 33,862. (No model.)

- To all whom it may concern:

Be it known that 1, WILLIAM ANTHONY JONES, a citizen of the United States, and a resident of est Brighton, Staten Island, in the county of Richmond and State of New York, (post-office address Lathrop and Dickie avenues,) have invented certain new and useful Improvements in Motors and Compressore, of which the following is a specification.

This invention relates to rotary motors adapted to be driven by elastic fluids and to a particular improvement in such motors whereby the driving fluid operates expansively through a series of successive chambers. The improvement therefore relates specifically to that sort of rotary motors wherein the rotary pistons are in the form of intermeshing screws.

The main object of the invention is to so construct the motor that steam or other elastic fluid may be admitted thereto at a high pressure and after its successive expansion exhaust therefrom ata low pressure and yield a nearly-uniform turning moment available as motive power. this means the motor will have a great advantage over most of the former rotary motors, since thesurfaces which come in contact with the expanding fluid will remain at nearly-constant temperature,thereby avoiding the loss in efficiency in said former motors due to alternately heating and cooling such surfaces. This improved construction also makes it possible to expand the fluid advantageously through a much greater range of pressure than is possible with most former motors and enables the motor to be run economicallyatlow speeds.

Another object of the invention is to reduce to the minimum the loss due to any leakage of the fluid from one isolated space between the threads of the screw to the next one. This is accomplished partly by the construction of the periphery of the screws and their casing and partly from the fact that what fluid should'so escape will be available for work in the isolated space to which it has escaped.

Another object of the invention is to so design the motor that it may be easily and accurately constructed and also in a manner such that only radial action of the elastic fluid in the isolated spaces becomes effective, thereby avoiding end thrust on the screws and greatly augmenting the ease of operation and maintenance. To the accomplishment of these objects the invention consists in the construction, formation, and arrangement of parts hereinafter fully described and'claimed.

. In the accompanying drawings, which form a part of the specification, Figure 1 is a longitudinal vertical section through the motorcasing, taken in a broken plane indicated by the line 1 1, Fig. 3, which passes through the valve-chest and valve and through the axis of one of the screws, a part of said screw being left in elevation. Fig. 2 is a horizontal section through the motor, taken in the plane indicated by the line 2 2, Fig. 3, the screw being shown partly in plan. Fig. 3 is a vertical transverse section taken in the broken plane indicated by the line 3 3, Fig. Fig. 4 is a view similar to that in Fig. 2, showing a modification in the form of the threads of the screws. Fig. 5 is a diagrammatic illustration of the action of the elastic fluid in an isolated space, whereby rotary motion is im parted to the screws. Fig. 6 is a transverse section through an isolated space to illustrate the eflect of the expansive force of the clastic fluid therein.

The principal elements of the motor are the right-hand screw 7 and the left-hand screw 8,

which are mounted on shafts 9 and 10, re-

spectively, and the casing 11. In said cas ing are formed two cylindrical chambers intersecting each other laterally and longitudinally and in which said screws are mounted. In each of these screws the space between the threads deepens gradually from one endtof the screw to the other, so that the bottom of said space is a conical surface. The perimeter of each screw, however, is a cylinder. Each screw may therefore be readily and accurately turned up in a lathe-that is, with respect to the top of its threadsand the chamber for each screw may be readily and accurately bored out, so as to make a close fit with the top of said threads. The screws intermesh, as shown, so that the top of the thread of one engages the bottom of the space between the threads of the other. This causes the shafts 9 and 10 to converge, as shown. Said shafts are geared together preferably near their converging ends by gears 12 and 13, which are for the sake of cleanliness and ease of lubrication located within the casing 11, as indicated. The sides of the thread of each screw are concave and are such surfaces as would be formed by the helical corner of the intermeshing thread of the other screw, so that as the screws revolve together each of said corners is in contact with the side of the intermeshingth read of the coacting screw, thereby forming a seal throughout the overlap of the threads, which, together with the closelyfitting casing, cuts off from communication with each other the successive spaces between the threads that are formed by the intermeshing of the screws. By means of the cylindrical form of the outside of the screws this generating-helix is of the same shape throughout the length of the screws. This enables the sides of threads also to be finished in a lathe. These successive spaces are of snaillike form, as seen at 14 in Fig. 5, each increasing in depth from one end to the other. The successive isolated spaces also increase in volume from one end of the screw to the other, so that the elastic fluid taken in at one point along the length of the screw gradually expands as it moves therefrom to the exitport of the motor, which is indicated at 15, Fig. 1.

The elastic fluid may be admitted to the isolated spaces at any desired points along the length of the screws. This may be accomplished and controlled by means of a slide-valve, substantially as shown in Fig. 1 at 16. A chest 17 for this valve may be located upon the casing 11, to which an inletport is provided at 13 and an exhaust-port at 1'9. The driving fluid is admitted from the chest 17 into the isolated spaces of the screw 7 through ports 20 and to those of the screw 8 through the ports 21. The valve is in the cut-off position in Fig. 1, and by moving it in the direction of the arrow 22 the exhaustport 15 is disclosed and one or more of the ports 20, as desired. When the first one of the ports 20 is opened, the fluid is admitted to an annular groove about each screw-piston, as indicated at 23. From this groove the space between threads has its origin. A larger volume of driving fluid may be admitted to the screws by disclosing more of the ports 20. These ports are made narrower than the width of the tops of the screwthreads in order that those ports still covered by the valve shall not connect the isolated spaces. Obviously the groove 23 may be formed in part or wholly in the casing, or it may be omitted. Each screw is also provided with suitable packing to prevent the escape of the driving fluid. Such packing may be in the form of rings, as indicated at 24.

The casing for the screws and the steamchest is preferably made from a single casting or forging, the chambers for the screwpistons and the valve being bored therein and the outer bearings therefor being formed in the heads 25, 26, and 27, respectively,

threads at the sides of the space.

which may be bolted or otherwise suitably held in place in the ends of said chambers.

To counterbalance the end thrust of the screws due to the pressure of the fluid on the end of the screws in the spaces 28, into which it escapes on leaving the last isolated chambers, said space is connected by passage 29 with spaces 30 at the opposite ends of screws 7 and 8. the motor is reversed. I

In Fig. 3 the relation of the screws to one another is shown, also the relative location of the valve-chest and the series of ports 20 and 21, and the direction of rotation of the screws is indicated by the arrows 31 and 32.

This is especially important when 7 In Fig. 5 the diagram of forces effective in producing rotation of the screws is shown, and reference thereto will make more clear the eflect of an elastic fluid in the motor. This figure represents a section of the screw 7 on a surface generated by a line perpendicular to the axis of said screw and moving through the middle line of the bottom of the isolated space 14 and a section of screw 8 on a similar surface generated by a line perpendicular to the axis of said screw and moving through the middle line of the top of the thread 33 of screw 8, which meshes between the convolution of the thread of screw 7 that forms the lateral walls of the isolated space 14. The ends 34 and 35 of said space are formed by the said thread The outer surface of this space 14 is the cylindrical wall of the casing 11, and the inner helical surface is the bottom of the channel between the The View in this figure is taken looking along the axis of screw 7. The action of the elastic fluid in this isolated space is typical of its action in all the other spaces. The action thereof tending to cause the screw to revolve is indicated by the arrows P, which represent pressure against the wall of the case. The arrows N represent the pressure against the bottom of the isolated space, and the arrows T represent the resultant of these two pressures finally reacting against the top of the thread of the screw 8. The lines of direction of the pressure N pass to the side of the axis of the screw 7, showing that this pressure creates a moment tending to revolve the screw 7. This moment is equal to the sum of the forces N multiplied by their effective lever-arm and is equal to the sum of the forces T multiplied by the mean radius of the spiral forming the bottom of the isolated space. The resultant action of these forces is also graphically indicated by the lineT, which represents a pressure acting and reacting upon a portion of the end wall 35 of the space 14 and the helical surface forming the bottom of said space. The remaining portion of the wall 35 equals the wall 34, so that the action and reaction on these surfaces balance one another. The turning of the screw then may be said to result from the action of the forces T on that portion of the surface 35 which is opposed to the said helical surface. The forces of the expanding fluid acting in other directions also counterbalance each other between relatively-fixed walls, as indicated in Fig. 6 at X. These are the forces which tend to produce end thrust of the screws; but since they act parallel to the easing 11 they can produce no end thrust. This condition is brought about by the fact that the casing and the perimeter of the screws are cylindrical.

From the foregoing it will be seen that of the forces exerted by the elastic fluid as it gradually passes along the screw into successivelyformed isolated spaces none are made effective save those tending to revolve the screws.

In the form of motor above described both screwpistons share equally in the work. The work may, however, be thrown mainly upon one of them by varying the form of the threads, as shown in Fig. 4. Therein the spaces between the threads of screw 7' and the threads of screw 8 uniformlyincrease in width from the inlet-port to the exhaust-port, the distance from center to center of successive threads of each screw being constant in each case. In this instance the isolated spaces of screw 7 receive the greater volume of steam, and said screw therefore takes the brunt of the work, the other screw serving for little more than to interpose its intermeshing threads for abutments or end walls to the isolated spaces of screws 7 Because of this and because it is from the shaft of screw 7 that the power is taken the power transmitted by the gears, and consequently the wear upon them and the journals, is lessened. This mode of construction also facilitates the accurate fitting of one screw to the other, since in turning screw 7 into mesh with screw 8 the narrower convolutions of screw 7 will first enter the wider spaces between the threads of the screw 8, and should they fail to mesh perfectly the screw 7"may be readily withdrawn and the defect remedied.

The motor is operated and controlled by the movement of the valve 16 to admit more or less steam or other elastic fluid into the ports 20 and 21. It maybe reversed by admitting the steam at port 15 through the hollow valve from the inlet 18 and disclosing the ports 20 and 21, so as to provide an outlet for the steam (through port 19) before the compression thereof offsets the power applied thereby to the screws.

Though the apparatus as set forth above is designed primarily for operation as a motor, it is obvious that by applying power to the shaft 9 it may be run as a compressor, the fluid to be compressed being admitted at port 15 and discharged at that one of the ports 20 or 21 at which it reaches the desired degree of compression. Operated as a compressor it has advantages over former compressors in that it may be directly connected to an electric motor and run at a high speed, also in that it avoids all the loss due to clearancespace and lifting-valves, that it requires no fly-wheel, and that the progress of the elastic fluid through all passages is sensibly uniform.

This apparatus, which, as already stated, may serve in the capacity of a motor or a compressor, may be varied in proportion and in form of parts in ways other than those already cited without departing from the spirit of my invention.

I claim as my invention- 1. In a rotary motor or compressor, a casin g having suitable inlet and exhaust ports for an elastic fluid and having two cylindrical chambers intersecting each other laterally and longitudinally, in combination with a right-hand screw in one of said chambers,and a left-hand screw in the other one of said chambers, each of said screws having a cylindrical perimeter fitting the side walls of its chamber and having the bottom of the space between the convolutions of its thread on the surface of a cone, the sides of said thread being so formed that the thread of one screw will intermesh with that of the other screw and closely engage the same throughout the entire distance of the overlap and also closely engage the bottom of the space between the threads, thereby forming an effective seal be tween the isolated spaces of each screw.

2. I In a rotary motor or compressor, a casing having two cylindrical chambers intersecting each other laterally and longitudinally, in combination with a right-hand screwin one of said chambers, a left-hand screw in the other one of said chambers, each of said screws having a cylindrical perimeter fitting the side walls ofits chamber and having the bottom of the space between the convolutions of its thread on the surface of a cone, a valve chamber on said casing having a series of inlet-ports communicating with the isolated spaces of the screws and an exhaust-port, and a valve for controlling said ports, substantially as set forth.

3. In a rotary motor or compressor, acasing having suitable inlet and exhaust ports for an elastic fluid and having two intersecting cylindrical chambers in combination with a right-hand screwin one of said chambers, and a left-hand screw in the other one of said chambers, each of said screws having a cylindrical perimeter fitting the side walls of its chamber and having the bottom of the space between the convolutions of its thread on the surface of a cone, the thread of one screw intermeshin g with that of the other and extending to said conical surface and each havingits side walls concaved, for the purpose set forth.

4:. In a rotary motor or compressor, a casing having suitable inlet and exhaust ports for an elastic fluid and having two intersecting cylindrical chambers in combination with a right-hand screwin one of said chambers, and a left-hand screw in the other one of said chambers, each of said screws having a cylindrical IIO perimeter fitting the side walls of its chamber and having the bottom of the space between the convolutions of its thread on the surface of acone, each screw intermeshing with the other and having an annular space about it at the inlet-ports, from which the space between the threads of the screw has its beginning.

5. In a rotary motor or compressor, a casing having suitable inlet and exhaust ports for an elastic fluid and having two intersecting cylindrical chambers in combination with a right-hand screw in one of said chambers, and a left-hand screw in the other one of said chambers, each of said screws having a cylindrical perimeter fitting the side walls of its chamber and having the bottom of the space between the convolutions of its thread on the surface of a cone, each screw intermeshing with the other and having a space between the casing and the end thereof opposite the exhaust-port which communicates with the space at the exhaust-port end of the motor, as and for the purpose set forth.

6. In a rotary motor or compressor a casing having suitable inlet and exhaust ports for an elastic fluid and having two intersecting cylindrical chambers, in combination with a right-hand screw in one of said chambers, and a left-hand screw in the other one of said chambers, each of said screws having acy- 7. In a rotary motor or compressor a casing having suitable inlet and exhaust ports for an elastic fluid and having two intersecting cylindrical chambers, in combination with a right-hand screw in one of said chambers, and a left-hand screw in the other one of said chambers, each of said screws having a cylindrical perimeter fitting the side Walls of its chamber and having the bottom of the space between the convolutions of its thread on the surface of acone, the screws intermeshing and the sides of the threads of each screw being a surface such as would be generated by the helix forming the corner of the intermeshing thread of the other screw, so that as the screws revolve there is a line of contact between the sides of the thread of each screw and the corresponding helical corner of its engaging screw, thus forming a seal between the isolated spaces of each screw.

8. In a rotary motor or compressor, acasing having two intersecting cylindrical chambers in combination with a right-hand screw in one of said cham bers,aleft-hand screw in the other one of said chambers, each of said screws having a cylindrical perimeter fitting the side walls of its chamber and having the bottom of the space between the convolutions of its thread on the surface of a cone, a valve-chamber on said casing having a series of ports communicating with the spaces between the threads and at the ends of the screws and a valve in said chamber for controlling said ports and providing for the'admission and discharge of the elastic fluid to effect an advance or reverse movement of the screws.

9. In a rotary motor or compressor, a casing having suitable inlet and exhaust ports for an elastic fluid and having two intersecting cylindrical chambers in combination with a right-hand screw in one of said chambers,-

and a left-hand screw in the otherone of said chambers, each of said screws having a cylindrical perimeter fitting the side walls of its chamber and having the bottom of the space between the convolutions of its thread on the surface of a cone, each of said spaces beginning at a point between the ends of its respective screw and terminating at one end thereof,and the screws intermeshing one with the other.

Signed at New York, in the county of New York 'and State of New York, this 17th day of. October, A. D. 1900.

WILLIAM ANTHONY JONES.

Witnesses:

DELBERT H. DECKER, ETHEL L. LAWLER.

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