US3490851A - Circular flow air compressor or diffusion motor - Google Patents

Description

Jan. 20, 1970 s. KRZYSZCZUK 3,490,851

CIRCULAR FLOW AIR COMPRESSOR OR DIFFUSION MOTOR Filed Sept. 29, 1967 2 Sheets-Sheet 1 IN VEN TOR.

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u 5 26 060,480 m2 vszc 20,6, Vie V I United States Patent Oifice 3,490,851 Patented Jan. 20, 1970 3,490,851 CIRCULAR FLOW AIR COMPRESSOR OR DIFFUSION MOTOR Edward Krzyszczuk, 1352 N; St. Louis Ave., Chicago, Ill. 60651 Filed Sept. 29, 1967, Ser. No. 671,736 Int. Cl. F01d 1/20, 3/00, /08

US. Cl. 41574 3 Claims ABSTRACT OF THE DISCLOSURE A fluid diffusion motor or compressor consisting of a casing containing a rotor, ribs formed on the inside surfaces of the casing and the periphery of the rotor, defining helical fluid guidance channels leading from one end of the casing to the other, and axially-extending fluid-compression or diffusion lobes substantially transverse to said guidance channels.

This invention relates to turbo fluid motor or compressor devices, and more particularly to an improved turbo fluid diffusion motor or compressor of the type employing a rotor having lobes cooperating with the internal surface configuration of the casing associated with the device.

The main object of the invention is to provide a novel and improved fluid diffusion motor or compressor of the type wherein the working fluid moves in a generally helical or circular path of flow, the device being simple in construction, being economical to manufacture, being highly efficient in operation, and being relatively compact in size.

A further object of the invention is to provide an improved fluid diffusion motor or compressor device which can be fabricated from common material, which is readily applicable for use for a wide range of purposes, especially those requiring medium fluid pressures or low volume fluid supply conditions, the machine having a minimum number of parts so that it is relatively easy to maintain it in operating condition.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIGURE 1 is an end elevational view of a fluid diffusion compressor constructed in accordance with the present invention.

FIGURE 2 is a longitudinal vertical cross-sectional view taken substantially on the line 2-2 of FIGURE 1.

FIGURE 3 is a transverse vertical cross-sectional view taken substantially on the line 33 of FIGURE 2.

FIGURE 4 is a longitudinal cross-sectional view taken through a modified form of fluid diffusion compressor constructed in accordance with the present invention.

FIGURE 5 is a transverse vertical cross-sectional vie-w taken substantially on the line 5--5 of FIGURE 4.

FIGURE 6 are graphs showing the changes in fluid pressure and fluid velocity of the working fluid as it passes around the interior of the Working chamber of either form of the invention illustrated in FIGURES 1 to 5, passing from intake to exhaust, either in the case of use of the device for developing positive fluid pressure or for developing negative pressure (vacuum).

FIGURE 7 is a fragmentary enlarged cross-sectional view taken substantially on line 7-7 of FIGURE 2.

Referring to the drawings, and more particularly to FIGURES 1, 2 and 3, 11 generally designates an improved circular flow fluid-diffusion compressor constructed in accordance with the present invention. In the typical example presented, the working fluid may be any gas, for example, air, whereupon the device 11 is employed as an air compressor. Thus, the compressor 11 comprises a generally cylindrical casing 12 in which is axially-journaled a rotor designated generally at 13. The rotor 13 is provided with the axial drive shaft 14 which may be driven by any suitable prime mover, such as an electric motor, a gasoline engine, or the like. The shaft 14 is suitably journaled at the opposite ends of casing 12, for example, in ball-bearing units 15 and 16, said opposite ends being sealed in any conventional manner to prevent leakage of fluid through the bearings or through the end wall portions of the casing adjacent thereto.

The end wall 18 adjacent ball-bearing unit 16 is provided with one or more suitable air-admission apertures 19, and the opposite end of casing 12 is provided with the air-outlet conduit 20. Casing 12 is formed on its inside surface spaced parallel helical ribs 21 defining helical fluid guidance channels leading from the intake end of the casing to the outlet end thereof, namely, helicallyarranged channels leading from the space adjacent wall 18 to the opposite end of the casing, namely, to a space 22 in communication with the outlet conduit 20, as is clearly shown in FIGURE 2.

The rotor 13 is formed with helically-arranged fluidcompressing lobes 24 having a pitch opposite in sense to that of the helical ribs 21 so that the lobes 24 are substantially transverse to the ribs 21. Thus, as shown in FIGURE 3, the successive lobes 24 are uniformly-spaced around the axis of the rotor and each lobe 24 comprises a relatively steep fluid-compression face 25, acting as a leading face, intersecting with a gradually rearwardlysloping diffusion surface 26 defining the trailing surface of the lobe, rotation being in a clockwise direction, as

viewed in FIGURE 3.

The rotor ribs or lobes 24 are thus asymmetrical, similar to those disclosed in the previously issued Patent No. 3,279,750 to Edward Krzyszczuk, although the lobes may have relatively sharp crests, if so desired. As in said prior patent, each lobe has a relatively steep front wall portion 25 and a relatively gently-inclined rear wall portion 26 connected with the front wall portion by a crest, shown at 27, having a relatively short radius of curvature. The inclined relatively long rear wall portion 26 is arcuately-curved, but has a relatively long radius of curvature as compared with the radius of curvature of the crest 27 or of the relatively steep front wall portion 25. In the typical embodiment disclosed in FIGURES 1, 2 and 3, the lobes 24 are identical in contour and subtend equal angles from the axis of shaft 14 and are at equal radial distances therefrom.

The spiral or helical lobes 24 cooperate with the helical ribs 21 in a manner substantially similar to that described in the aforesaid prior Patent No. 3,279,750 to provide a successive build-up of fluid pressure from the right end of casing 12 toward the left end thereof, as viewed in FIGURE 2, responsive to the rotation of rotor 13, with the fluid being driven constantly through the helical channels defined between the successive ribs 21. Thus, in operation, atmospheric air enters the inlet opening 19 and passes into the space adjacent end wall 18, being thereafter acted upon by the helical fluid-compression lobes 24. The lobe crests 27 cooperate with the ribs 21 and the inside wall surface of the housing to define venturi passages whereby the pressure of the fluid is successively increased as it is moved from the inlet end toward the outlet end of casing 12. FIGURE 6 illustrates the change in fluid pressure and the successive cyclical changes in fluid velocity as the air travels from the right end of casing 12, as viewed in FIGURE 2, toward the left end thereof. Thus, the upper graph of FIGURE 6 shows the fluid-pressure curve 29, and the fluid-velocity curve 30. In the graph the fluid velocity is designated by the symbol V as representing maximum absolute fluid velocity, and by the symbol V as representing minimum absolute fluid velocity, the maximum fluid relative velocity V (curve 30") being that of the fluid located adjacent the lobe crests 27 and the minimum fluid relative velocity V being that of the fluid which has entered into the diffusion spaces leftwards of the crests 27, as viewed in FIGURE 2, along the helical diffusion surfaces 26. In accordance with well-known principles, each drop in velocity is accompanied by a corresponding increase in pressure, the pressure being increased in the diffusion spaces leftwards, as viewed in FIGURE 6, with each cycle of change of fluid velocity. The fluid-compression steps occur successively in the successive diffusion sections, the fluid being concurrently driven through the helical channels leading to the compressor discharge space 22. The velocity and direction of the compression steps are indi cated by the arrow V in FIGURE 6 (similar to the motion of an escalator from a lower to an upper floor). By the provision of the ribs, suitably-spaced to define said helical guidance channels, excessive fluid turbulence is avoided and the fluid is smoothly and efficiently guided to the discharge space 22 while its pressure is increased, stage-by-stage, in the helical channels leading to the discharge space 22. Each lobe 24 represents or defines one stage.

In FIGURE 6, the upper portion of the graph has the base line a representing atmospheric pressure and the limit between velocity and relative velocity. The lower portion of the graph is generally similar to the upper portion thereof, but represents the inverse action of the device. Thus, in the lower portion of the graph, the dotted curve 30' again represents the changes in fluid relative velocity from the intake end of the device,

namely, the right end thereof, as viewed in FIGURE 2, to the discharge end, namely, the left end thereof, relative to the base line a, with the symbol V representing maximum fluid relative velocity and the symbol V representing the minimum fluid relative velocity. In the lower portion of the graph of FIGURE 6, the dotted base line b represents atmospheric pressure and the serrated, gradually ascending full-line curve 29' represents the ascent of the pressure wave P as the lobes move.

The compressor of the present invention operates by a combination of two principles: (1) the principle governing the diffusion process, and (2) the principle of centrifugal force.

The action resulting from the diffusion process is achieved through changing of the relative velocity (velocity'of the fluid particles relative to the lobes 24 of the rotor) designated by the dotted curve 30' in FIGURE 6.

The action resulting from the centrifugal process is achieved through changing of the absolute velocity (velocity of the fluid particles relative to the housing and to the earth) designated by the dotted curve 30 in FIG- URE 6.

The diffusion process takes place only at the portions of the diffusion sections where the high fluid relative velocity is being converted to fluid pressure. While the relative velocity is being decreased at the diffusion sections, the absolute velocity is being increased (by increased radius relative to the rotor axis). The higher velocity causes higher centrifugal force to act on the fluid particles at the outer ends of the diffusion surfaces 26.

In the upper portion of the graphical representation of FIGURE 6, the maximum output positive pressure is designated by P, and represents the output air pressure of the compressor 11 shown in FIGURES 1, 2 and 3. The associated lobe contour is diagrammatically illustrated at the lower portion of FIGURE 6, showing the relationship of the lobe contour with the corresponding changes in fluid velocity and pressure, as illustrated by the pressure characteristics of the machine shown in the upper graphs of FIGURE 6. The direction of rotor movement is illustrated by the arrow U in FIGURE 6. The direction of fluid flow in relation to the rotor is designated by the arrow 51 in FIGURE 5.

The lower portion of FIGURE 6 indicates the relationship between the pressure wave, rotor and fluid. The rotor moves with a speed and direction represented by the arrow U, and the pressure wave P moves with the speed of the rotor, like waves on the surface of the ocean being pushed by the wind while the water particles move much slower or do not move at all. The fluid particles 51' move much slower than the pressure wave.

Suction vacuum is designated by the symbol P at the left end of FIGURE 6 below the line a.

The rotor 13 is preferably built-up of a plurality of contiguous, substantially similar sections with spacers 36 of thermal insulation material interposed between the sections, the thermal spacers 36 extending over the major portions of the contiguous faces of the respective rotor sections, so that said rotor sections are substantially thermally-shielded relative to each other. This allows the sections to be at different operating temperatures without substantial heat flow axially along the rotor, thereby promoting the efficiency of the cooperation between the lobes and the internal ribs 21 of casing 12. By minimizing thermal leakage along the rotor, it is possible to allow each rotor section to be thermo-dynamically independent of the other rotor sections, although as will be understood,. a certain amount of thermal leakage occurs at the peripheries of the adjacent sections because they are in abutment to a limited degree in these regions. The areas of abutment, as will be apparent from FIGURE 2, are relatively small, thereby retarding the flow of heat by conduction from one rotor section to the next.

The insulating discs 36 may be contained in coopcrating, opposing recesses provided in the radial surfaces of the respective rotor sections. For example, adjacent surfaces may be provided with opposing cooperating recesses 39 and 40, as shown in FIGURE 2, formed to define a cavity to receive an associated insulating disc 36.

While FIGURE 3 shows the lobes 24 and the ribs 21 as being substantially transverse to each other, it will be readily apparent that within the spirit of the present invention, the angle between ribs 21 and lobes 24 may have any value between 30 and Over this range of variation of the angular relationship between lobes 24 and ribs 21, the compressor will still function employing the same principle above-described, namely, the conversion of the high-velocity fluid at the diffusion portion 26 of lobes 24 into fluid of increased pressure by the combination of the principles employed in axial flow and centrifugal compressors.

In the modification illustrated in FIGURES 4 and 5, the compressor comprises a casing 12' in which is longitudinally-journaled a rotor 13' mounted on a shaft 14' and supported in the opposite end portions of the casing 12 by the respective ball-bearing assemblies 16' and 15'. It wil be seen from FIGURE 4 that the rotor is provided with radial lobes 24' which extend longitudinally of the rotor 13' and which comprise the relatively steep leading faces 25 and the relatively large-radius, smoothlyinclined diffusion faces 26', corresponding to the lobe faces 25 and 26 of the embodiment illustrated in FIG- URES 1, 2 and 3. The rotor 13 is formed with a plurality of longitudinal bores 40' circularly-spaced around shaft 14' for the purpose of lightening and cooling the rotor. Casing 12' is provided at its right-end Wall, as viewed in FIGURE 4, with intake passages 19' and is provided at its left end with a discharge passage 20'. The inside su-rface of casing 12 is formed with helical grooves 41 defining fluid guidance passages leading from the right-end portion to the left-end portion of the casing with relation to rotor 13 which rotates in a clockwise direction, as viewed in FIGURE 5. The rotor is formed with an integral helical rib 21 having a pitch which decreases from the right-end portion of the rotor toward the left-end portion thereof, as viewed in FIGURE 4, the rib 21' defining fluid guidance passages between its adjacent convolutions, corresponding to the fluid guidance passages defined between the helical ribs 21 of the form of the invention illustrated in FIGURES 1, 2 and 3. The longitudinally-extending radial lobes 24 cooperate with the helically-grooved inside surface of casing 12' to provide increments of increased fluid pressure from the right-end portion of the compressor toward the left-end portion thereof by employing the same general principles used in the embodiment of FIGURES 1, 2 and 3. As the rotor revolves, the high-pressure fluid is converted into highvelocity fluid by the action above-described in the :relatively restricted nozzle passages defined between the crests of the lobes and the ribs defined by the guidance grooves 41. The pressure of the fluid increases in steps with a characteristic generally similar to that shown in the upper portion of FIGURE 6 and represented by the fluidapressure curve 29. The high-pressure fluid moves into a discharge chamber 43 at the left end of casing 12', as viewed in FIGURE 4, the space 43 communicating with the discharge passage 20'. The casing 12 is formed with an axially-extending skirt portion 44 which is closely received within a corresponding sleeve portion 45 provided on the left end of rotor 13, defining a labyrinthine seal between the rotor and the casing in this region.

By the provision of the helical rib 21' of decreasing pitch, the area of the working passage for the fluid is decreased from the intake end toward the outlet end of the compressor, in accordance with the compression of the working fluid. The shallow grooves 41 guide the compressed fluid in its movements between the convolutions of the helical rib 21 until the fluid reaches a row of final diffusers defined by internal stationary inwardly-projecting blade elements 47 provided in the left-end wall member 48 of casing 12. The blades 47 define therebetween diffusion passages leading to the discharge chamber 43 which, as above-mentioned, communicates with the discharge passage 20'.

The helical rib 21', may have convolutions differing in size and shape and need not be uniform in cross-section. Similarly, the lobes 24 or 24' of the embodiments disclosed and illustrated need not be identical in shape, and may differ in size and shape.

The longitudinal bores 40' may be employed for ventilating the rotor 13. For this purpose, some of the entering air which is admitted into the compressor at the passages 19' flows through the bores 40' and communicates with a ventilation air space 50 provided in the end assembly 48 of casing 12. The space 50 surrounds the bearing unit 15, serving to cool the bearing unit, since air can flow therethrough as the rotor revolves. Space 50 is effectively sealed with respect to the high-pressure fluid space 43 because of the relatively close fit between skirt member 44 and sleeve member 45 which are free with respect to each other to allow rotation of member 45 with respect to the stationary member 44, but which are so closely spaced as to define a relatively constricted tortuous passage therebetween limiting leakage to a relatively small amount.

As shown in FIGURE 4, sufficient clearance is provided between the right end of rotor 13' and the right-end wall of casing 12', to allow ventilating air to enter the bores 40'.

The right end bearing assembly 16' is exposed to atmosphere so that it is adequately ventilated.

It will be noted that in the embodiment of FIGURES 1,

2 and 3, venturi action occurs between the lobes 24 and the inside surface of casing 12 responsive to the rotation of rotor 13, with the ribs 21 defining fluid guide channels which convey the fluid toward the discharge end of the compressor. Similarly, in the embodiment i1- lustrated in FIGURES 4 and 5, the venturi action occurs between the lobes 24' and the shallow-grooved inside wall surface of casing 12, with the helical rib 21' defining fluid guide channels between its adjacent convolutions, the guide channels likewise leading toward the discharge end of the compressor. Thus, in the embodiment of FIGURES 4 and 5, the helical rib 21' performs a function similar to that of the spaced stationary internal ribs 21 of the embodiment of FIGURES l, 2 and 3, except that the helical rib 21' is mounted on rotor 13' and rotates therewith, whereas the ribs 21 are fixed and remain stationary.

In the embodiment of FIGURES 4 and 5 wherein the lobes 24' are radial and extend parallel to the axis of rotor 13', the principle of operation is substantially similar to that of the device shown in prior United States Patent No. 3,279,750 except that substantially increased eificiency is obtained by the provision of the generally helical rib 21 on the rotor which defines the fluid working space leading toward the outlet end of the device, namely, leading toward the pressure gas-outlet passage 20' in FIGURE 4. Further improvement in efliciency is obtained because of the diminishing pitch distance between the adjacent turns of the rib 21', whereby the working space is tapered in cross-sectional area from the inlet end of the compressor toward the outlet end thereof, due to the diminishing difference between the adjacent turns of rib 21 from the right end toward the left end of rotor 13', as viewed in FIGURE 4. The improvement in efficiency arises from the fact that shaft 14', rotating at substantially constant speed, causes the compressed fluid to increase in fluid density as its pressure is increased in accordance generally with well-known gas laws, assuming substantially constant fluid flow rate through the apparatus, and further assuming no very large temperature gradient along rotor 13. Thus, in accordance with the well-known gas laws, assuming constant temperature, the volume occupied by a given quantity of gas will decrease inversely in accordance with its increase of pressure. The decrease in spacing between the adjacent turns of the helical rib 21' is preferably in accordance with this general physical law.

In accordance with the present invention, the helical inwardly-projecting ribs 21 in the embodiment of the apparatus shown in FIGURES 1, 2 and 3 may have gradually decreasing spacings between adjacent ribs to provide working spaces of correspondingly decreasing cross-sectional area from the low pressure toward the high pressure end of the machine.

The divergence angled or between the diffusion surface 26 or 26 and the inside wall surface of the housing 12 or 12 is an important design factor. The divergence angle may be between 5 and 20 degress. This angle is such that in cooperation with the passage defined by the adjacent housing wall surface it provides an eflicient diffusion action. Also, the front portions 25 or 25 of the lobes (subtending an angle O in FIGURE 7) and the diffusion surfaces 26 or 26' (subtending an angle D in FIGURE 7) are shaped so as to provide high centrifugal forces on the fluid particles and to minimize decompression of fluid at the orifice sections.

While various specific embodiments of an improved fluid machine have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art.

What is claimed is:

1. A fluid machine of the character described comprising a casing having an inside wall surface of generally circular cross-section, a rotor mounted in said casing, spiral fluid-engaging axially-extending spiral lobes on said rotor extending continuously from end-to-end on the rotor, each lo'be having a relatively steep forward wall surface and a gradually-sloping rear wall surface with a relatively short-radius corner portion between said forward and rear wall surfaces, respective fluid inlet and outlet passages at the opposite end portions of the casing, the lobes being contoured with respect to the inside wall surface of the casing to provide a combination of diffusion action and centrifugal action on fluid therebetween responsive to rotational movement of the rotor in the casing, and spiral rib means on the casing substantially transverse to the lobes defining a substantially helical fluid working space between the lobes and the inside wall surface of the casing, said working space extending continuously from the fluid-inlet end portion of the casing to the fluid-outlet end portion of the casing, said rotor comprising a plurality of contiguous substantially similar sections, the sections being formed with cooperating opposed recesses having relatively narrow radially extending flat peripheral abutting surfaces at the peripheries of the recesses, and respective discs of thermal insulating material interposed between the sections and substantially filling the recesses in the contiguous faces of the abutting rotor sections, and wherein the cross-sectional area'of said fluid working space decreases gradually from the inlet end portion of the casing towards the outlet end portion of the casing.

2. The fluid machine of claim 1, and wherein the spacing between the adjacent turns of said spiral rib changes gradually from one end of the rotor toward the other.

8 3. The fluid machine of claim 1, and wherein the divergence angle between the rear wall surface of each lobe and the adjacent inside wall surface of the casing is between 5 and 20 degrees.

References Cited UNITED STATES PATENTS 760,776 5/1904 Campbell 253- 981,311 1/1911 Rivers 253-65 1,581,683 4/ 1926 Nicholls. 2,400,899 5/1946 Wilcox 25365 X 2,808,225 10/ 1957 Johnson 25 3-65 X 511,964 1/ 1894 Merrill 253-45 2,241,782 5/1941 Jendrassik 25339.15 X

FOREIGN PATENTS 1,831 of 1907 Great Britain.

641,095 4/ 1928 France. 485,491 10/ 1929 Germany. 605,902 11/ 1934 Germany.

932 of 8 Great Britain. 7,762 of 1911 Great Britain. 316,468 8/ 1929 Great Britain.

EVERETTE A. POWELL, JR., Primary Examiner US. Cl. X.R. 4l575

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