US1944875A - Sealing means for annular cylinder engines - Google Patents

Description

Jan. 30, 1934; F. A. BULLINGTON SEALING MEANS FOR ANNULAR CYLINDER ENGINES Original Filed Feb. 26. 1926 3 Sheets-Sheet 1 INVENTON Fan/r ABM/#7 730 ATT'ORNEY 1934- a F. A. BULLINGTON 1,944,875

SEALING MEANS FOR ANNULAR CYLINDER ENGINES Original Filed Feb. 26. 1926 3 Sheets-Sheet 2 INVENTOR ATTORNEY w Jan. 30, 1934. F. A. BULLINGTON SEALING MEANS FOR ANNULAR CYLINDER ENGINES Original Filed Feb. .26. 1926 3 Sheets-Sheet 3 INVENT OR Fran/r flBw vzgfan,

ZV//// ///A ATTORNEY UNETED STATES? PATENT; osngg SEALING MEANS FOR ANNULAR CYLINDER- enemas Frank A. Bullington, Los Angeles, Calif., assignor to. Bullington Motors, Kansas City, Mo., a com-- men-law trust consisting of Solomon Stoddard, Ernest E. Howard, and Frank A. Bullington Application February 26, 1926, Serial- No. 90,838 Renewed April 20, 1933 10 Claims. (Cl. 286-7) My invention relates to sealing means for anthe zone of greatest pressure in the engine, the nular cylinder engines and more particularly for sealing means pressure being reduced at other those of the type illustrated in Letters Patent points to a degree only sufficient to maintain No. 1,497,481, issued to me under date of June the seal without excessive frictional retardation, 10, 1924, comprising pistons rotatable in an anthe principal object of the invention being to so nular cylinder chamber and arranged in pairs thus provide an effective seal with a minimum with the pistons of each pair diametrically opfrictional retardation of the moving element. posite each other, the pistons of one pair In accomplishing this object I have provided operating with those of another pair to constiimproved details of structure, the preferred forms tute action and reaction members and passing of which are illustrated in the accompanying 65 alternately through low and high pressure zones drawings, wherein at and adjacent to the points of intake, com- Fig. l is an enlarged side elevation of the cylinpression, expansion and discharge of the imder of an engine embodying my improvements, pelling medium. one of the stator housing members being re- While my invention may be employed to admoved and a part of one 01 the pistons broken 70 vantage in engines wherein the impelling meaway for better illustration. dium is merely expansible, as in steam engines, Fig. 2 is a sectional View on the 1ine 2-2, Fig. it is particularly adaptable for use with those 1, particularly illustrating my sealing means with of the explosion type, and I will limit the folspecific reference to the rotor.

lowing description to its application to engines Fig. 3 is a detail perspective view of the sealing 75 of that type, with the understanding that such rings emp oyed i e form of Sealing means limitation is merely for clarity in disclosure and illustrated in Fig. 2.

without intention of excluding use of the inven- 4, 5 and 6 are enlarged, sectional views tion with other types with which my sealing of modified forms of sealing means. means may be employed. Fig. 7 is a sectional View on the line 77, Fig. 0

One of the principal difficulties encountered in 2, of my improved sealing means with specific practical use of engines of this type is leakage reference tothe piston. between the stator and rotor elements, due to g. 8 is a detail perspective View of P s the extremely high pressure encountered in the e P 8 Sealing means in pa ed elation. combustion phase of operation. A uniform seal- Fig. 9 is an enlarged section on the line 99, ing means suniciently effective to prevent leakage Fig. 2, illustrating the piston sealing ring in its in the high pressure zone will so burden the rotor relation to the spark lug chamber. in the low pressure zones as to seriously detract Fi 10 is a lflfi graph illustrating t e from its effectiveness, whereas, if the sealing is Variable conditions of pressure to which the sealsuiiiciently loose to permit free operation ofthe ins means is subjected, wi particular reference rotors, the impelling medium will leak in the high to the rotor sealing means. pressure zones, particularly in the explosion type g- 11 i a Similar graph illustrating Va iable of engine, wherein the initial combustion prespr in h rotor alin m ans.

sure constitutes a thrust at the confining ele- Referring more in dhtail t0 the dmWihgSI- 4 ments, as distinguished from a more gradual 1 designates a Stator, Comprising an annular f cylinder 2 having a rotor throat 3 and bearings Two factors must, therefore, be taken into 4 for a qheft t e Cy der end only of which is consideration. First, proper support of the seali ustrated, but which may be of a form and have mg element, to ithstand variable and suddenly connections like that shown in my issued patent increased pressures while maintaining sealing ilbOVB referred relation with the stator. Second, efiective seal- T18 Walls 6 and 0f the throat 3 a e pering of the rotor without such excessive friction pelldiculal t0 that Shaft, and ovable in the pressures as to interfere with effective operation. throat are rotor members 8 and the member 8 Having these factors in mind and first with bein fi 110 e t, a d the member 9 to a 50 particular reference to the rotor, I have devised tubular shaft 10 rotatable onthe shaft 5, the a sealing means for engines of this type having rotor 8 mounting the paired pistons 11, 12, and positive, adjustable support to maintain a seal the rotor 9 the paired pistons 13, 14, all of which at the stator and a variable pressure contact with pistons are adapted for travel in the cylinder 2 the rotor, and wherein the zone of greatest presand operate as described in my said 'Letters sure of the sealing means on the rotor embraces Patent.

The pistons 11, 12, 13 and 14, being rotatable within the annular cylinder under force of expansion of a fluid impelling medium operative in the working chambers formed between them, carry the rotors about a common center, but the pistons of the separate pairs being adapted for independent movement, produce a difierential in the rotor movement; consequently the rotors must be sealed against escape of the fluid medium between their side walls and the walls of the stator throat, and also between their facing side walls. The last-named sealing is effected simply by contact of the facing walls of the rotors, which are preferably provided with wear plates 15 and 16, countersunk within the rotor walls and anchored by pins or the like 17 to hold the plates against rotation in their countersunk grooves. By providing wear plates for insuring the seal between the rotors, I am enabled to employ an unbroken surface for the piston sealing means, as will be presently mentioned.

Referring now to the sealing means for one of the rotors, with the understanding that such description relates equally to both:

Within the wall 6 of the rotor throat is an annular socket 18 having a circumferential wall 19 perpendicular to the throat wall, a stepped inner circumferential wall comprising the inner and outer seats 21 and 22, and a base wall 23 having an inclined outer portion 24 and perpendicular stop portion 25 adjacent the seat 22.

Located within the socket 18 is an annular sealing ring 26, right angular in cross section, having a body part 27 projected slightly into the rotor throat, with its inner face in contact with a wear plate 28 countersunk in the outer face of the rotor 8. The wear ring is of slightly greater width than the body 27 of the sealing ring in order to provide a frictional bearing for the ring within the range of its variable movement hereinafter described, and is anchored to the rotor by a pin or the like 29, the periphery of the sealing ring lying immediateiy within the socket and bearing snugly against its outer wall 19 under 1 normal conditions, the ring having a laterally turned flange 30 at its outer edge for facilitating its assembly in the engine. Ring 26 is provided with a notch 26 (Fig. 3) receiving a pin 26" (Fig. 2) on the stator to anchor the ring.

It is apparent that with the arrangement of stator, rotor and pistons above described, the sealing ring is subject to distortion in two directions-first radially under the thrust of fluid pressure medium through the space in the throat between the rotor and throat walls, and second laterally by pressure medium entering between the ring and the outside wearing plate on the rotor. The ring is also subject to distortion under twisting strains on the rotor during operation of the engine. Consequently, the sealing ring must be maintained under pressure radially and laterally to maintain an eiiective sealing contact between the body of the ring and the rotor, and between the periphery of the ring and the stator.

If the pressure of the impelling medium were constant throughout the length of the cylinder, the problem of sealing would be a comparatively simple one. The pressure is, however, not constant, but variable at different points in the cylinder. At the point of intake of fuel mixture (port 31) the pressure is neglible. During compression the pressure increases, tending to force the fluid medium between the sealing ring and stator wall, and between the ring and rotor wall. At the point of fire the pressure rises suddenly to its maximum at combustion, so that there is a substantial thrust of the fluid medium against the sealing ring and between the ring and rotor. After combustion the pressure gradually de creases as the expansion takes place, until finally the pressure vanishes and there is a tendency to minus pressure. The sealing ring must be supported with sufficient pressure to present displacement or distortion in the high pressure zone, but if the same pressure were continued throughout the l ngth of the cylinder, the frictional resistance of the ring to travel of the rotor would unduly burden the rotor and prevent efiicient operation of the engine. Consequently I provide a variable tension for the rotor sealing means in the two directions under which it is subjected to thrust from the fluid medium. The first resistance is in the nature of an annular supporting ring 32, right-angular in cross section, the body part 33 of which has a wall parallel with but spaced from the rotor wall, and a bevelled, outer edge 34 with the bevelled inner edge 35 on the body of the sealing ring 26, forming a wedge contact, tending to expand the sealing ring, outwardly toward the stator wall and then support it in place, and incidently to press the sealing ring laterally against the rotor.

As the peripheral contact of the sealing ring with the stator wall is stationary as distinguished from its moving contact with the side wall of the rotor, a close fit of the sealing ring with the, stator is sufficient to maintain the seal with the pressure.

traction of the metals results in a creeping of one,

Wedge face on the other against the tension. of and subject to return by the lateral pressure ring presently mentioned. With an angle of contact much less than that of repose, there would be no slipping action, and with the angle much greater than that of repose, there would be no positive support for the sealing ring under the relatively sudden thrust of the ring by the impelling medium.

Seated upon the flange 33 of the supporting ring is an annular, dished backing spring 36, the inner rim of which is pressed against the wall portion 85, and the outer rim of which bears laterally against the body of the supporting ring, the tension of the backing spring being directed against the body of the supporting ring to yieldingly force the bevelled edge of said supporting ring against the bevelled edge of the body of the sealing ring to force the sealing ring radially outward against the wall 19 of the socket 1,8 in the stator, and also force the sealing ring against the wear plate on the rotor. Lateral pressure of the seal ng ring against the wear plate on the rotor is, however, principally exerted by a tension ring 37, dished or Z-shaped in cross section, with one edge resting in the seat 22 of the socket 18, with its hub bearing against the outer wall 20 of the socket, the outer rim on the spring bearng against the inner face of the body 27 or" the sealing ring 26, thereby exerting a lateral pressure on the sealing ring to maintain its contact with the rotor.

This arrangement provides separate support and spring tension for the sealing ring, which tends to hold the ring adjustably against the stator and spring tension the ring against the rotor.

In order to relieve the rotor from excessive frictional resistance during its travel through the low pressure zones, I graduate the spring 36 and tension ring 37 so that at the points where the sealing ring is subjected to the greatest pressure, its distortion is resisted to an extent sufiicient to retain it in function relation with the rotor and stator, the resistance being gradually diminished toward the zones of lesser pressure by decreasing the thickness and consequently the tension of the rings (see Figs. 2 and 3).

I have found from experience that by so graduating the tension rings or springs I am able to hold the pressure in the annular cylinder without unduly burdening the rotor.

A comparison of the curves shown in Figs. 10 and 11 will clearly show why this is true. In Fig. 10 distances from the base line to the curve indicate the fluid pressures above and below atmospheric pressure exerted on the sealing means due seal.

to conditions in the engine; and points lengthwise along said base line indicate the various conditions existing at different points around the cylinder. In Fig. 11 the distances from the base line indicate the spring pressure exerted by the sealing means at various points along the same, while the points lengthwise along the base line indicate the points around the cylinder corresponding to those in Fig. 10. It will be noted upon comparison of these curves that the resilient means exerts its smallest pressure at the intake and exhaust points around the cylinder, corresponding to the relatively low pressures exerted by the gases in the cylinder during intake and exhuast. The intake zone on both curves is indicated by Int. the exhaust zone by Exh.. The compression part of the curves are indicated by Comp and the ignition point on each by Fire. The maximum pressure of combustion is indicated by Comb and the expansion portion of each curve by Exp. It will further be noted that the spring pressure indicated by the curve in Fig. 11 gradually increases until a point a short distance beyond dead center indicated by D. C. is reached, after which the same decreases until the intake portion is again reached. Furthermore, the greatest spring pressure is exerted at a point corresponding substantially to the zone of highest pressure in the cylinder as indicated by the curve in Fig. 10, the spring pressure varying more gradually than the pressures in the cylinder but being always sufficient at all points to provide a This construction greatly reduces friction as it provides a strong spring pressure only where needed.

While I have specifically mentioned but one set of sealing elements in combination with their rotor, these elements are duplicated in connection with the other rotor, as is clearly understandable from the drawing, particularly Fig. 2.

Also while I have specifically described a definite combination and construction of sealing elements, such may be modified without departing from the invention. For illustration, in Fig. 4 I show the sealing ring as composed of two pieces 38 and 38the sealing ring socket is rectangular in cross section as distinguished from one having stepped and inclined walls; a difierent form and arrangement of the supporting. ring. 33; and

a difierent form of tension ring 37', although it is apparent that the force exerted by this modilied form will effect the same result as in the preferred form shown in Fig. 2.

Also in Fig. 5 I show the sealing ring as having a bevelled contact with the wall of the stator socket, a support 39 attached to the rotor and having a bevelled edge corresponding to the bevelled edge of the stator socket, a spring 40 interposed between a flange 41 on the sealing ring, and a wedge 42 interposed between the base flange of the sealing ring and an angular groove 43 which tends to force the wedge outwardly between the sealing ring and the flange 39 of the L-shaped support 39 on the rotor, a spring 44 being interposed between the base of the L- shaped bracket and the base of the sealing ring to expand the sealing ring against the inclined wall of the socket, thereby thrusting the sealing ring to contact with the rotor and to contact with the stator.

In Fig. 6 I have simplified the construction by combining the sealing ring support and the spring for the supporting member into one piece of dished form having lateral tension and wedge contact with the sealing ring, the tension ring for exerting lateral pressure or" the sealing ring against the rotor being substantially the same as in the preferred form.

In all of the forms the variable tension on the sealing ring is effected by graduating the supporting spring and the tension ring for the sealing member to relieve the frictional resistance in the low pressure zones, where the pressure can be retained with a lesser strain and resistance than in the zones of higher pressure.

Particular attention is directed to the functional similarity of the sealing ring supporting wedge element employed in the various forms of the rotor sealing means illustrated in Figs. 2, 4, 5 and 6 and to the fact that in the type of engine illustrated, the exposure of a portion of one of the surfaces of the rotor sealing ring to the direct actionof the fluid under pressure in the cylinder is unavoidable. In the forms shown in Figs. 2, 4 and 6 the sealing rings are adapted to have a portion of their outer peripheral surfaces exposed to fluid pressure and are supported by a relatively positive wedge ring member effective radially to withstand the action of the fluid pressure. In Fig. 5 the seaiing ring is adapted to have its outer peripheral surface completely covered at all times and to have a side surface exposed to the fluid pressure and to be supported on its other side by a relatively positive wedge ring member effective laterally to withstand the action of the fluid pressure.

The rotors proper do not extend into the cylinders but terminates slightly within the rotor throat and have extensions 46 extending into the cylinder and provided with ears 47 which are projected through openings 48 in the inner piston walls to about the center of the pistons, where they are fixed to the pistons by pins 49, the ears being reduced and merging into the extensions 46 on an angle forming an inclined shoulder 50 for contact with a correspondingly angling surface on the inner piston wall. A gasket 51 is located between the rotor extension shoulder and the inclined piston wall to seal the joint therebetween. 3

Each piston is mounted on one only of the rotor members and has a lip 52 extended into the throat and terminating adjacent the periphery of the other rotor member, thereby providing irregular surfaces on the piston and rotor members, which must be sealed to prevent the escape of impelling fluid from the cylinder. As the pistons are subjected to severe centrifugal force and, at the point of firing, to high pressure from expansion of the impelling medium, these factors must be taken into consideration in designing the sealing means.

The preferred form of sealing means for such parts comprises a peripheral groove 53 near each end of the piston, seating a ring 54 which is adapt.- ed for projection from the groove to sealing contact with the cylinder wall. The ring 54 has a side wall lying flush against the front wall of the groove and a bevelled inner face adapted for contact by the oppositely bevelled inner face of a ring 55, also seated in said groove and adapted for sealing the wall of the groove and combining with the first-named sealing member to prevent escape of fluid medium from the portion of the chamber within which it is confined; the contacting faces of the rings 54 and 55 are on an angle slightly greater than that of repose for the materials of which the parts are composed; i. e. between 20 and 30 degrees. The ring 53 is not inherently expansible but being subject to unequal pressures on the cylinder wall, due to the centrifugal force generated in operation of the engine, is provided with other means for maintaining its sealing contact throughout its length. Being subject to greater wear at the outside or" the cylinder than along the side walls and being subject to a minus pressure at the inner portion of the cylinder, I have graduated the radial thickness of the ring to compensate for the wear at its outer portion and have provided for expanding the ends of the ring to maintain a sealing contact with the inner portion of the cylinder and with the rotor, this graduated thickness or crescent-shape being also carried into the construction of the ring 55.

Located within the inner portion of the groove is an expander spring 56, which lies idly in the outer portion of the groove between the bottom of the groove and the rings 54 and 55 but is provided with thrust bends 57 along the sides of the piston to exert a moderate force against the rings to expand them outwardly to sealing contact with the side walls of the cylinder, and more pronounced bends 53 at the inner ends of the springs to exert a greater force on the inner ends of the sealing rings to overcome the centrifugal force which would otherwise tend to space the sealing rings from the walls of the cylinder.

One end of the expander spring is provided with a hook 59 which engages freely within a depression 60 at the inner portion of the piston groove to hold the spring in place, the opposite end of the spring being free within the groove.

One end of the ring 54 is anchored by a positioning member 61, one end of which seats in a depression 62 in the base of the groove 53 and the other end located in a notch 63 in the inner wall of the ring, the anchor being under tension to force the end of the ring against the side of the rotor to maintain a sealing contact therewith.

At its opposite end the ring 54 is step-cut at 64 to fit a step-cut 65 in the end face of a rotor sealing block 66, having a transverse face 67 seated on the peripheral surface of the complementary rotor member and an end face 68 in sealing contact with the outer wall of the rotor throat; the block 66 constituting a sealing means for preventing escape of the impelling medium through the throat and the step-cut relation of the block and ring maintaining the sealing contact under variable conditions of the operation.

The block 56 is of wedge-shape form, having one of its side surfaces seated against a side wall of the piston ring groove 53 and its other side surface inclined and forming an acute angle with its rotor seating surface 67, and is provided with a companion wedge-shaped groove sealing member 71, having an inclined side surface 72 seated on the inclined side surface of the block, the wedge angle of the inclined surface being slightly above that of repose (between 20 and 30 degrees) to prevent shifting of one member on the other under pressure of the fluid impelling medium, but permit movement of the two sealing members under tension of the expander spring 56.

The spring 56 is bent at its hooked end in a manner to exert an expanding force on the rotor sealing member, which normally retains said member in its sealing contact with the rotor, the sprin having its thrust bearing on the wedge member '71 only.

In order to hoid the parts described in place prior to their assembly in the cylinder I provide the rotor sealing blocks 66 and wedge member ll with apertures '73 and 74, through which a pin '75 is extended, the pin having a head '76 threaded into a socket l? in the piston wall, the shank of the pin extending loosely through the apertures in the block and wedge member and terminating in a socket '78 in the inner wall of the piston roove, thereby permitting free movement of the block and sealing member while preventing their escape from the groove.

When the impelling medium is a hydrocarbon mixture, it is fired from a spark plug '79, having electrodes and 81 located within a socket 82 formed in the wall of the cylinder and communicating with the cylinder through a port 83. As the plug is threaded into the socket and closes the same, the impelling medium is trapped within the socket and held therein under pressure after firing. The impelling medium thus trapped will exercise a force on the piston and piston sealing rings when the piston passes over the port 83 sufiicient to distort the piston ring and permit leakage unless some means is provided for overcoming this effect.

To prevent this action I provide the sealing ring with a radial opening 84 which communicates with the port 83 when the ring moves over the port so that the trapped impeliing medium passes from the spark plug socket through the port 83 and the ring opening 84 into the space at the bottom of the ring; the expansive force of the impelling medium then acting to force the cylinder sealing ring outwardly and aug- What I claim and desire to secure by Letters Patent is:

1. A packin comprising a sealing ring adapted to have face contact with a moving member, a supporting ring having wedge contact with the sealing ring to positively maintain contact of the sealing ring with a member and having a supporting face parallel with the contacted face of the sealing ring, and separate pressure rings urging the sealing ring to contact with said moving means and the supporting ring to contact with the sealing ring, said pressure rings being of varying thickness, giving them space variation of flexibility.

2. A packing ring comprising a split ring having an inner contact face, a supporting ring having an outer contact face contactiin the split ring, the faces of said rings opposite their contact faces being parallel to each other, said contact faces being arranged at an an le to said parallel faces, and a sie thrust spring ring of varying thickness giving said ring a space variation of flexibility contacting with one of said rings for imparting side thrust thereto.

3. A packing comprising a split ring havingan inner contact face, a supporting ring having an outer contact face contacting with the face of the split ring, the faces of said rings opposite their contacting faces being parallel to each other, said contact faces being arranged at an angle to the parallel faces, a thrust ring contacting with one side of the split ring, and a spring ring contacting with one side of the supporting ring whereby said rings have independent side thrust imparted thereto.

4. A packing means comprising a split ring having a cylindrical outer face and a tapered inner face, a supporting ring contacting with the tapered face of the split ring, a side thrust spring ring contacting with said split ring, and a side thrust spring ring contacting with said supporting ring. 7

5. A packing comprising two rings arranged one within the other, the outer ring being split and having a conical inner face, the inner ring being a continuous ring and having a conical outer face contacting with the inner face of the outer ring, and a resilient side thrust ring contacting with one side face of the outer ring.

6. A packing comprising two rings arranged one within the other, the outer ring being split and having a cylindrical outer face and a radial flange at its inner face, said flange having an inner conical face, the inner ring having an outer conical face contacting with the conical face of the outer ring, and a resilient ring for imparting side thrust to said inner ring for expanding said outer ring.

7. A packing comprising two packing rings arranged one within the other, the outer ring being a split ring having a cylindrical outer face and a radialflange at its inner face, said flange having an inner conical face, the inner ring having an outer conical face contacting with said outer ring, and a side thrust spring ring of varying thickness giving it a space variation of flexibility contacting with the side surface of one of said rings and adapted to exert side pressure thereon.

8. A packing comprising a split ring having a bevelled inner face, a supporting ring having a bevelled outer face located Within said split ring with the bevelled face thereof contacting with the bevelled face of the split ring, a spring ring having varying thickness giving it space variation of flexibility and a peripheral flange located adjacent to and contacting with one face of said split ring, said spring ring adapted to hold the opposite face of the split ring in contact with a movable member, and a second spring ring of varying thickness giving it space variation of flexibility located adjacent to and contacting with one face of the supporting ring for imparting a thrust thereto so as to cause the bevelled faces to ride on each other, thereby controlling the expansion and contraction of the split ring, the outer face of the split ring and the inner face of the supporting ring being parallel to each other and arranged at an angle to the bevelled faces of the rings.

9. A packing comprising a split sealing ring adapted to have face contact with a moving i member, a supporting ring contacting with a face of the sealing ring, said contacting faces being arranged at an angle to a face of the sealing ring opposite to said contacting faces, and means contacting with one side of the sealing ring and with I,

one side of the supporting ring whereby said rings have independent side thrust imparted thereto in the same direction.

10. A packing comprising a split ring adapted to have face contact with a moving member, a l

direction.

FRANK A. BULLINGTON.

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