Fluid Engine

Abstract

A pressurized fluid engine operable at high efficiency and in which pressure fluid flows therethrough with low pressure and fluid losses, having a pressure fluid passage to a rotor which has a hollow confined interior bounded on substantially its entire inner periphery by inclined surfaces facing the axis of rotation, and an annular self-centering seal whose central passage is in communication with the rotor. A pressurized fluid engine having a rotor subjected to internal fluid pressure with a conduit portion to the rotor in which is positioned an annular seal that is self-centering and held in position by the pressure of the fluid and which is substantially free of rotational friction wear.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of our copending application Ser. No. 93,288, filed Nov. 27, 1970.

Description

BACKGROUND OF THE INVENTION

One of the features of this invention is to provide a high efficiency, low pressure and fluid loss rotary engine operated by or operating on pressure fluid, either gaseous or liquid, flowing through a rotor, a self-centering floating seal and with the rotor having an interior construction that efficiently cooperates with the pressure fluid and in which the combination including the seal, rotor interior and low friction loss fluid passages in the rotor provides high efficiency power development with low losses both in pressure and fluid.

DESCRIPTION OF THE PRIOR ART

Two prior patents of which applicants are aware are U.S. Pat. No. 3,387,564 issued June 11, 1968 and U.S. Pat. No. 3,495,841 issued Feb. 17, 1970 . Both of these are for pressure fluid devices with fluid seals but neither is related to an engine such as a fluid motor turbine operating at high efficiency and with low pressure and fluid losses and using the combination of elements that are present in applicants' invention to achieve these results.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a shortened side elevational view partially in longitudinal section illustrating one embodiment of the invention.

FIG. 2 is a transverse sectional view taken along line 2--2 of FIG. 1.

FIG. 3 is an enlarged fragmentary sectional view taken substantially along line 3--3 of FIG. 1.

FIG. 4 is a transverse rear sectional view taken substantially along line 4--4 of FIG. 1.

FIG. 5 is a fragmentary view illustrating a second embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The engine 10 of the illustrated embodiment comprises an elongated casing 11 having a rotatable shaft 12 therein whose forward end extends from the casing and may be used for operating a small metal grinding wheel 13 for example.

The engine, a term used generically to indicate a device for converting fluid pressure into power, is designed to operate on compressed gas such as compressed air although the invention is operable with pressurized fluids generally including gases and liquids. The illustrated embodiment shows an engine casing 11 provided with a fluid inlet means 14 in the form of a rearwardly extending tubular extension integral with and substantially centrally of a rear cover 15 for the casing 11. This tube 14 is knurled as illustrated and receives the end 16 of a flexible compressed air pressure hose.

The rear cover 15 to the casing 11 comprises a fixed base member with an inner surface 17 around the fluid inlet passage 18 in the tube 14.

The casing 11 is transversely enlarged at its rear end or the end adjacent the tube 14 to provide a chamber 19 in which is positioned a hollow rotor 20. This rotor is of rigid plastic of which nylon is a good example and is attached to the knurled rear end 21 of the metal drive shaft 12 so that the rotor 20 and shaft 12 as well as the fluid inlet passage 18 are all coaxial with each other and with the central axis of rotation 27.

The shaft 12 is mounted for rotation on spaced ball bearing devices 22 of which one is located adjacent the rotor 20 as shown and another (not shown) is located adjacent the forward end of the casing 11.

The pressure fluid engine 10 has therefore as the power producing part the rotor 20 rotatable about its axis of rotation 27 by fluid pressure forces including reaction on the fluid foil surfaces 25. The rotor 24 is hollow and is bounded by end walls which as illustrated are front 46 and rear 48 walls. Between these walls 46 and 48 is a peripherally circular wall 49. In one of the end walls 46 and 48, here shown as the front wall 46, there is provided a central opening 54 through which the pressure fluid flows as indicated at 44 into the hollow interior 24 of the rotor.

Inwardly of the central opening 54 is a smooth vaneless inner chamber portion 55 and adjacent and outwardly thereof is the outer vaned impelling portion 56 in which are located the plurality of vanes 57 of which two are shown in the illustrated embodiment. Each vane 57 comprises a fluid foil section as shown in FIG. 2 each having an arcuately curved air foil surface 25. Each surface 25 leads to and directs fluid through a nozzle 29 and each nozzle is located between an adjacent pair of the impelling portion surfaces 25. Thus the adjacent vanes 57 have cooperating relation and define the nozzles 29 therebetween.

In the illustrated embodiment each fluid foil section vane 57 has a leading edge shown at 42 in FIG. 2 that is shaped so as not to constitute a substantial obstacle to, or retarder of, fluid flow over and around the leading edge.

Each vane 57 has its impelling surface 25 curved smoothly and arcuately outwardly relative to the axis of rotation 27 and each terminates in a trailing end shown at 58 in FIG. 2 lying in the peripheral circular wall 49.

In the illustrated embodiment each vane 57 extends substantially 180.degree. about the axis 27 and each discharge nozzle 29 is straight, short, unrestricted and substantially tangential as illustrated by the discharge flow arrow 39.

The rotor 20 at the central opening 54 is provided with projecting means embodied in the shaft end 21 that extends from one end wall 48 toward and to the opposite end wall 46. This shaft end 21 or projecting means is provided with the large internal and axial fluid passage 23 and large side openings 59 so that the projecting means 21 with the internal passage 23 and openings 59 along with its end opening 60 define smooth outwardly extending flow surfaces whereby fluid flow into the hollow rotor 20 from the central opening 54 is turned smoothly from an axial direction 44 to radial as illustrated by the flow arrows 61 to enter the vaned portion 56 of the rotor with a radial component as illustrated by the headed ends 62 of the flow arrows 61.

The fluid inlet means to the interior 24 of the rotor not only includes the fluid inlet passage 18 but also includes the fluid entrance means or chamber 31 aligned with the passage 18 and of larger diameter. Positioned within this chamber 31 is an annular floating seal 32 having a central opening 33 aligned with the fluid inlet passage 18, a cylindrical outer surface 34 snugly and floatingly received in the fluid entrance chamber 31 and an end 35 for bearing against the base member 17 around the fluid inlet passage 18 to make sealing engagement therewith. The seal 32 also includes means comprising the inner end surface 36 that is within the chamber 31 for subjecting the seal to the pressure fluid within the interior 24 of the rotor. This is achieved by having the fluid inlet passage 18 which supplies fluid to the rotor interior in communication not only with the rotor interior but also with the fluid entrance chamber 31 and the fluid passage 23.

With this construction the slight clearance between the seal outer surface 34 and the outer cylindrical wall of the fluid entrance chamber 31 permits the rotor 20 and the shaft 12 to which it is attached to rotate around and relative to the seal 32. Because of the small spacing of the rotor around the seal 32 there is very little fluid loss in the space 37 and there is also very little loss of pressure. The short exit passages 29 in the rotor 20 also have low friction losses so that the result is that the rotor 20 and shaft 12 rotate relative to the floating seal 32 and the combination comprising the seal 32, inclined inner surface means 25 of the rotor and the short exit means 29 which are free of fluid compressing restrictions convert the energy of the flowing fluid 38 to the rotary power in a highly efficient manner with negligible losses of pressure and fluid.

The exhaust fluid 39 from the rotating rotor flows into the casing chamber 19 in which the rotor is located and then rearwardly through a number of openings 40 in the rear cover 15 as illustrated in FIG. 4.

As can be seen in FIG. 2 the inclined surface means comprises a linear series, here two, of inclined surfaces 25 symmetrically arranged around the inner periphery of the rotor 20 and each is provided with its own exit passage 29. These exit passages may be of uniform diameter as shown or they may be outwardly flaring but in any event are substantially free of fluid compressing flow restrictions as would be true of an exit with a converging throat.

In the preferred construction each rotor surface 25 lies at least approximately along a spiral, and preferably an Archimedes spiral, whose center is substantially at the axis of rotation 27.

The base member surface 17 which in the illustrated embodiment is the inner rear surface of the cover 15 and the sealing end 35 of the floating seal 32 are complementary in that they engage each other in sealing relationship over the entire end sealing surface 35 of the seal. The opening 33 in the seal is a cylindrical surface that is substantially parallel to the outer cylindrical surface 34 of the seal. The end surfaces 35 and 36 of the seal are substantially parallel to each other.

The fluid exit passages 29 from the rotor interior 24 are defined by substantially cylindrical surfaces as illustrated by the lower passage 29 in FIG. 1. The side 41 of each passage 29 that is furthest from the axis of rotation 27 is substantially a smooth continuation of the inclined surface 25 that leads to the particular exit passage 29. The inner side or the entrance portion 42 of each passage that is closest to the axis 27 is rounded as illustrated in FIG. 2 to reduce resistance to rotation by engagement of this entrance portion 42 with fluid flowing from the interior 24 through the exits 29. In the illustrated embodiment this rounded surface portion is substantially the leading edge of an airfoil.

The fluid entrance means or chamber 31 shown most clearly in the enlarged detail section of FIG. 3 is defined by an inner annular flange 43 that is positioned inwardly of the floating seal 32 when the interior 24 of the rotor is subjected to fluid pressure. This spacing of the flange 43 from the inner end surface 36 of the seal provides the pressure chamber 31 in which the pressurized fluid acts to press the seal 32 to the right as viewed in FIGS. 1 and 3 and hold the seal in engagement with the surface 17 so that the rotor rotates around the seal 32. Because the seal 32 can move laterally on the surface 17 when necessary the seal is not only floating but is self-centering. This is true because assuming that the seal is off center at the beginning of operation when the pressurized fluid 44 is first admitted the initial rotation of the rotor 20 immediately centers the seal. As can be seen particularly in FIG. 3 the inner or entrance opening 33 of the seal is aligned with the fluid inlet passage 18 as well as with the inner openings 45 defined by the inner circumference of the flange 43. The diameter of this opening 45 in the illustrated embodiment is substantially the same as the diameter of the opening 33 in the floating seal.

The fluid engine of this invention converts the pressure of a fluid flowing through a rotatable rotor to rotary power at high efficiency with low pressure loss and fluid loss. A very important feature of the invention is the provision of the floating seal 32 which is self-aligning as it is held either against the casing cover 15 in the first embodiment or adjacent the rotor and rotates therewith in the second embodiment. In both embodiments fluid pressure holds the seal against its sealed surface.

The seal which may be made of a synthetic plastic such as a phenol-formaldehyde resin operates in both embodiments with only very small clearance in the vicinity of the outer surface 34 and 53 of the seal with a typical clearance in both embodiments being 0.0005 inch. Both the leakage of fluid and wear on the seal is very low and there is very little drag caused by the seal which as stated immediately becomes self-centered. This seal permits lateral expansion of the rotor 20 under internal pressure without binding even at its outer surface 47 that is adjacent the end cover 15 and 115. The seal although preferably a phenolic resin may also contain additional desirable materials such as lubricating graphite, reinforcing fibers and the like.

The fluid force on the seal holding it in sealing engagement does not vary substantially during operation. Thus it does not materially vary with the speed of rotation and the fluid flow is substantially constant.

The illustrated embodiments have been shown in combination with a small grinder wheel 13 as one important use of this invention is in operating such a grinder at very high speeds. When used as a grinder the dimensions are quite small so that the unit can be easily held with one hand by the operator.

In the embodiment of FIG. 5 the seal 50 is located in a chamber 51 in the rear cover 115 and bears against the rear surface 52 of the rotor 120. Pressure fluid from the inlet passage 118 enters the chamber space 51 behind the seal 50 and presses it against the rotating rotor so that the seal after becoming self-centered or self-aligned rotates with the rotor 120 and clear of the chamber 51 side and end walls.

The invention described and claimed herein is applicable to an engine broadly defined as any machine by which physical power is applied to produce a physical effect. Thus the pressurized fluid engine of this invention may be either a fluid motor in which the pressure of the fluid is used to exert mechanical power or a pump in which mechanical or physical power is applied to the fluid itself. Thus in the case of the fluid motor the pressure of the fluid itself produces the physical effect while with the pump the physical power is used to apply pressure to the fluid.

Having described our invention as related to the embodiments shown in the accompanying drawings, it is our intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the appended claims.

Claims

1. A pressure fluid engine, comprising: a rotor rotatable about a central axis, said rotor being hollow and bounded by end walls with a peripherally circular border wall therebetween, said rotor having a central opening in one of said end walls, a plurality of nozzles in said border wall, a smooth vaneless inner chamber portion adjacent said central opening and a plurality of peripherally successive outer vaned impelling portions in said border wall, each of said vanes comprising an airfoil section having an arcuately curved airfoil surface leading to and directing fluid through a said nozzle, each nozzle being located between an adjacent pair of said impelling portions; projecting means defining a smooth axial flow surface extending from the other of said rotor end walls toward said one end wall in the region of said axial opening whereby fluid flow in a path including said central opening and said inner chamber portion has axial and radial components lying at about 90.degree. to each other; a fixed base member adjacent said rotor having a fluid opening communicating with said central opening in said rotor, the base member having a surface around its said fluid opening and adjacent the outer surface of said one end wall of said rotor; a self-centering seal having opposite ends adjacent said base member and rotor surfaces and a fluid flow passage through the seal aligned with said rotor central opening and said base member opening for passage of said pressure fluid through the seal; and means for subjecting one said seal end to said pressure fluid to press the other said end in sealing engagement with the adjacent said surface, thereby resulting in full fluid pressure being applied to said airfoil vanes of said rotor impelling portions for maximum turning torque about said axis.

2. The engine of claim 1 wherein said seal is positioned at said one end within a cylindrical chamber having a side wall closely adjacent to the corresponding side of said seal.

3. The engine of claim 2 wherein said chamber is in said rotor and said other end of the seal bears against said base member surface.

4. The engine of claim 2 wherein said chamber is in said base member and said other end of the seal bears against said rotor outer surface.

5. The engine of claim 2 wherein said seal is tubular with an inner cylindrical surface substantially parallel to said cylindrical outer surface and with opposite ends substantially parallel to each other.

6. The engine of claim 1 wherein said impelling portions and nozzles are symmetrically arranged around said rotor, and each said nozzle is of circular cross section.

7. The engine of claim 1 wherein said rotor is coaxially mounted on a shaft rotatable therewith, the rotor and shaft are rotatably mounted in an enclosing casing having an end wall adjacent said rotor comprising said fixed base member.

8. A fluid pressure engine operable at high efficiency with pressure fluid flowing therethrough and with low pressure and fluid losses, comprising: a fluid passage means for said pressure fluid having a fixed base member therearound and sealed thereto; a rotor having a surface adjacent to said base member and said fluid passage means rotatable about an axis of rotation that is coaxial with said fluid passage means, said rotor having a hollow interior with mechanical energy conversion means therein subjected to said pressure fluid flowing therethrough, a substantially circular axial fluid portal communicating with said rotor interior and said fluid passage means; means forming an annular axial chamber in one of said base member and said rotor surface and adjacent the other, said chamber communicating with said fluid passage means and said rotor portal; an axially movable pressure fluid operated, annular, floating seal having a central opening aligned with said fluid inlet means for fluid flow therethrough into the rotor, a cylindrical outer surface snugly and floatingly received in said chamber, an end sealing means for bearing in sealing engagement against the other of said base member and rotor surface adjacent said chamber to prevent fluid leakage; and means for subjecting said seal to said pressure fluid to maintain said sealing engagement.

9. The engine of claim 8 wherein said seal is tubular, the chamber is in said rotor, and the seal bears against said base member with the rotor rotating relative to the seal.

10. The engine of claim 8 wherein said seal is tubular, the chamber is in said base member, and the seal bears against said rotor and rotates therewith substantially clear of said chamber means.

11. The engine of claim 8 wherein said rotor is coaxially mounted on a shaft rotatable therewith, the rotor and shaft are rotatably mounted in an enclosing casing having an end wall adjacent said rotor in which said fluid conduit entrance means is located with a portion of said end wall comprising said fixed base member.

12. A pressure fluid engine comprising a rotor rotatable about a central axis, said rotor being hollow and bounded by end walls with a peripherally circular wall therebetween, said rotor having a central opening in one of said walls, said rotor having a smooth vaneless inner chamber portion adjacent said central opening and an outer vaned impelling portion, each of said vanes being of airfoil section having a substantially rounded leading edge, and an inner surface spiraling smoothly, arcuately outwardly and terminating in a trailing end lying in said peripheral circular wall, said adjacent vanes having cooperating relation and defining tangential substantially unrestricted discharge nozzles therebetween. each of said vanes extending substantially 180.degree. about the axis of said rotor; projecting means defining a smooth outwardly extending flow surface from said other of said end walls toward said central opening whereby fluid flow into the hollow rotor from said central opening is turned smoothly from an axial direction to radial in said vaneless portion of the rotor to enter said vaned portion with a radial component; a fixed base member adjacent said rotor having a fluid opening communicating with said central opening in said rotor, the base member having a surface around its said fluid opening and adjacent the outer surface of said one end wall of said rotor; a self-centering seal having opposite ends adjacent said base member and rotor surfaces and a fluid flow passage through the seal aligned with said rotor central opening and said base member opening for passage of said pressure fluid through the seal; and means for subjecting one said seal end to said pressure fluid to press the other said end in sealing engagement with the adjacent said surface, thereby resulting in full fluid pressure being applied to said airfoil vanes of said rotor impelling portions for maximum turning torque about said axis.

13. The engine of claim 12 wherein said seal is positioned at said one end within a cylindrical chamber having a side wall closely adjacent to the corresponding side of said seal and wherein said chamber is in said rotor and said other end of the seal bears against said base member surface.

14. The engine of claim 12 wherein said seal is positioned at said one end within a cylindrical chamber having a side wall closely adjacent to the corresponding side of said seal and wherein said chamber is in said base member and said other end of the seal bears against said rotor outer surface.