US2796837A

US2796837A - Rotary machine

Info

Publication number: US2796837A
Authority: US
Publication date: 1957-06-25
Anticipated expiration: 1974-06-25

Description

June 25, 1957 2,796,837

HEDwlG ALl'cE WALLIMANN, NEE HUNZIKER ROTARY MACHINE Filed May 6, 1954 4 Skets-Sheet 2 k7 Imm; 5.73645 June 25, 1957 2,796,837 HEDWIG ALICE WALLIMANN, NEE HuNzlKER ROTARY' MACHINE Filed May 6; 1954 Fig.4

` 4 Sheets-Sheet 3 42 lz? 53 4 fr o "fn |15 I| Il 34` Fig 5 47 43 4o 4 4o L 4/ 44 s" 9 FB /48 /Nws/vm/a" HEJHIG luce Mimi/AMY' Mee /wvz/RE@ 47 lmm.

June 25, 1957 2,796,837

HEDwlG ALICE wALLlMANN, NEE HUNzlKER ROTARY MACHINE Filed May 6, 1954 4 Sheets-Sheet 4 F|g.8

F598 FigO Fig. Fig/12 Ams/wax United States Patent O ROTARY MACHINE Hedwig Alice Wallimann, ne Hunziker, Zurich, Switzerland Application May 6, 1954, Serial No. 428,056

Claims priority, application Switzerland May 16, 1953 1s claims. (ci. 10s- 121) The presentinvention relates to a rotary machine with sliding sealing elements, and has the primary object of providing a machine of this type wherein the said sealing elements or vanes secure a reliable sealing effect in every position thereof.

It is another object of the present invention to provide a machine of this type which relies exclusively on the structural shape of its cooperating components, and has no recourse to elastic deformations thereof under the action of centrifugal force.

It is yet another object of the present invention to pro vide at least a multiple line contact, preferably however, practically an area contact between the curved stationary surface and the inner ends of the said sealing elements cooperating therewith.

It is still another object of the present invention to secure an automatic separation of the lubricant used for the lubrication of mutually moving contacting surfaces of components of a machine of this type from a medium of lower specific weight pumped by the same, owing to the action of centrifugal force.

With these and other objects in view, I provide a rotary machine with sliding sealing elements comprising in combination: a stationary outer mantle, a closure lid fixedly attached to the said mantle, a rotatable casing arranged inside the said mantle and journalled therein and in the said closure lid, a stationary guide drum arranged eccentrically inside the said rotatable casing with clearance from the inner wall surface thereof even at the nearest point, shaft portions extending axially from both ends of the said stationary drum through the said rotatable casing, an inlet duct and a discharge duct being provided in the said shaft portions and communicating with an inlet part and a discharge part, respectively, issuing from the said drum into the eccentrical annular space enclosed between the said rotatable casing and stationary drum, vanes slidably guided in radial slots in the circumference of the said rotatable casing, bridge pieces rigid by connecting diametrically opposite vanes with one another and going with ample clearance round the adjacent shaft portion extending from said stationary drum, and inserts fulcrumed in the end faces of the said vanes for rocking motions about axes parallel to the axis of the said rotatable casing and contacting the circumference of the said drum, the said eccentrical annular space enclosed between the said rotatable casing and the said stationary drum being divided into separate compartments sealed from one another by the said sliding vanes and inserts thereof, and, upon rotation of the said casing firstly increasing in volume from the said inlet part onwards, and then decreasing in volume towards the said discharge part, the said drum having a substantially elliptical cross section with the major axis at right angles to the eccentrical offset of the said stationary drum with respect to v-the said rotary casing, and the sealing faces of the said inserts contacting the surface of the said stationary drum in any position at least with a multiple line contact but preferably with an area contact, the gap between the said Mice sealing faces and the surface of the drum being every,- where smaller than the thickness of the film of lubricant applied to it.

The said bridge pieces establishing rigid connection between diametrically opposite vanes are either C-shaped or annular, and have an aperture surrounding the said shaft portion, the diameter of which exceeds the diameter of the said shaft portion so much that the centre of the said aperture 'coincides with the axis of the said'drum. Preferably the said inserts protrude at least partly beyond the end faces of the said inserts facing towards the said drum.

Recesses parallel to their axis of rocking may be provided in the sealing faces of the said inserts contacting the surface of the said drum. The ratio of offset of the centers of the said casing and drum to half the distance between diametrically opposite vanes is preferably equal to, or smaller than, 0.2. By this choice of eccentricity the differences in the curvatures of the drum surface as caused by the elliptical shape of the drum are comparatively small, and the sealing faces of the inserts can be better adapted to the same. Moreover the Width of the sealing face can be so selected that the gap formed at the points of greatest curvature between the drum and the segment has such a small width, that it can be com.- pensated by the lm of lubricant. In some cases one is, however, tied to a certain width ofthe vanes or inserts, respectively, which is to be selected at least equal to the full stroke. Since in thisy construction the vanes engage into slots of the casing, and behind the vanes there are air spaces, the volume of which varies periodically upon rotation of the casing a varying pressure is applied to the rear face of the vanes. This can be obviated in such a manner that the air spaces in the casing behind the vanes are put into communication with one another by means of conduits provided in the casing, for the purpose of equalisation of pressure.

The invention will be explained hereinafter with reference to embodiments illustrated by way of example in the accompanying drawings, in which:

Figs. 1 to 3 show an embodiment of a rotary machine with sliding sealing elements or vanes according to the invention, Fig. l being a section along the line I-I o f Fig. 2, Fig. 2 being a section along the line II-II of Fig. 1, and Fig. 3 being an exploded perspective view showing individual components.

Figs. 4 and 5 show on a larger scale than the Figs. l and 2, two embodiments of vanes with rocking inserts.

Figs. 6 and 7 show in simplified representation, on a smaller scale than Figs. l and 2, two modifications of a rotary machine according to the Figs. l to 3. l

Figs. 8 to 14 show, on a larger scale than the Figs. 1 and 2, seven different embodiments of the sealing faces of the rocking inserts.

In the Figs. l to 4, a stationary cylindrical mantle 1 is open on the right hand side, and has -a foot 2. The mantle is provided with a covering lid 3 which has an inwardly directed hub 4. Of the screws 5 for the fixing of the lid 3 to the mantle 1, one only is shown in Fig. l. The mantle 1 is provided with an inwardly directed hub 101. Two

shaft portions

8 and 9 are passed through bores of the

hubs

101 and 4, respectively. Both

shaft portions

8, 9 are rigidly connected to the eccentrically mounted drum 10. ByV means of the key 6, the screw thread 7 and the nut 102 the shaft portion 8, and thereby also the drum 10, are fixed in the hub 101. In` the shaft portion 8, there is a conduit 11, which issues at 111 on the circumference of the drum 10. The shaft portion 9 contains likewise a conduit 12which issues at 13, i. e. on the side opposite the orice 111, ofi the drum 10 on the circumference of the drum 10. Around the drum a cylindrical casing 14 is' arranged, the axis of which coincides with the axis of the shaft portions 8 and V9and which is journalled with its closurelids a'dsl audits; hubs 17 and 18, rotatablyon the shaft 8,`9. The key`19 on the hub 18 serves for. keying-on a belt pulley (not shown). The hub 18 may alternatively be coupled directly to a driving motor, kafpacking gland not being absolutely necessary.

The cylindrical casing 14 has four

slots

20,21, 22, 23 offset uniformly `90 with respect to one another, andvall of them lying at an equal distance from the axis of the casing. In these slots,

vanes

24, 25, 26, 27 are arranged. In the ends of these vanes facing the drum, recesses are provided vinto which inserts 28, 29,30, V31, e. g. of metal or of artificial material, are pushed, which inserts perform rocking` movements'about a virtual axis parallel to `the vaxis of .the casing. -As will'be seen in Figs.` 1' to 3,. the vanes`24, 26'and 25,27 lying'opposite to one another, respectively, vare rigidlyconnected with one. another by a ring. 32, 33, respectively the central planes,V of the said vanespassing 'in anyposition thereof through the' axis of the said casing. .The ring 32 has for 'example an elongated hole 32 through which the shaft portion 9 is passed. In .the samemanner the ring 33 is shaped. 'A ring conduit34puts the air spaces located lat the outer `ends of the

vanes

24, 25, 26, 27 into communication with'one another for the purposeof equalisationof pressure. Various conduits serve for the supply ofthe lubricant. The latter is supplied at 35a (Fig. `l),'is'passed through the conduits 35h tothe bearings of the'two

shaft portions

8, 9 and also to the sliding surfaces between the drum 10 and the casing 14, whereby part of the lubricant gets into the Yring conduit 35e (Figs. l, 3), and from there through the conduits 35d of theV lid 15 to the bores 35 (Figs. l, 2, 4) of the rocking inserts. Owing to the action of centrifugal force the lubricant -eventually gets to the peripheral outer sides of theconduits and from there through the aperture 35e in the'flidlS'to the ring conduit 35j (Figs. 1, 3) of the hub 17, where it leaves the m'achine'at 35g. 'The' path 4ofthe oil as described is indicated in Fig. l'by arrows.

Inorder to ease the production of the lubrication conduits in the rotary casing the latterrnay be composed jof an outer portion k14a and 'aninner portion 141;, as

shown in "Fig v3. 'In the 'embodimentrepresented the 'space betweenthe'rotary casing 14 and the stationary l'drum 10 is subdivided by the vanesi24,25, 26, 27 or by their inserts'28, 29, 30,31, respectively, into `four compartments`36, 3,7, 38, 39 whicharejsealed against one another. Instead of four

vanes

24, 25, 26,27 two only, -or more thanf'four, vanes could be provided.

'In thefFigs. -4 .and '5 two embodiments of vanes with frocking inserts are shown by way of example, on a larger scale. In the embodiment according to Fig. 4 the vane -27 slides in the groove 23 provided` inthe casing 14.

For the'supply of the lubricant e. g. of oil, to the sealing faces 41 of the insert 31, the conduits 45 are provided. The insert 31 itself is capable of-rocking in the vane 27 In some cases itmay offersome difficulties to mill faultlessly fitting grooves into the casing. On the other .hand it is easier in certain circumstances to drill for ex- Sample circular bores and to establish the guide by two segments, are inserted, the sliding faces 48, 49 of which have a distance from one another which is adapted to the width of the vane 43 so as to provide a sealed guide for it. c n Y In the embodiments of uthe inserts 31 and 40, respec- VView of production to give the drumA 10 inthe axial direcand thereby -secure a multiple line contact.

tively, shownin Figs. 4 and 5 the sealing faces'41 (Figfll) of these inserts are curved` steadily for example shaped as parts of circular cylinders. Since the insert 31 (Fig. 4) in the recess 42 of the vane 27 is capable of rocking, it adapts itself by rocking as 'faraspossible to the curvature of the surface ofthe drum 16, so that between the drum surface and the sealingface ofthe insert there is practically an area seal established at least partly, i. e. at least a multiple line contact. The vane`27 has conduits 45 for the lubrication of the sealing and sliding face 11. These conduits 14S are connected tothe llubrication conduit35, which has an aperture also ont-he sealing face 41 of the insert 31 in order that the supply of lubricant to the sliding fa-ce41may besecured.

However, it is not necessary to have the sealing faces of the inserts, as shown in Figs. 4 and 5, steadily curved. The sealingfaces may alternatively have recesses. VSuch embodiments are shown by way of 'example Vin vthe Figs. `8 to l2. inthe embodiment according to Fig. 8 the sealing. face '51 of theinsert'50 is formed'undulatin'g. The crests of the waves'fr'm an envelope surface which is adapted to the drumsurface so that at any time atleast some wavefcrests slide upon the drum surface so that a multiple line Icontact Ais secured, and a similarly efficient Vseal is attained as with an 'areasealing according'to Figs. 4 and 5. Other shapes of sealing lfaces having recesses are shown in Figs. 9 to l2. InFig. 9 there is a triangular recess'51 provided. In the insert 50 according to Fig. l0 'the recesses areformed as grooves 51. In the embodiment according to Fig. 1l the sealing face has a domed shape, the apices of the do-mes sliding on the drum surface delimiting an envelope surface so that at least some ldomel apices slide at the same time on the drum surface, Fig. 12 shows an embodiment in whichtriangular recesses are provided in a zig-zag shape arrangement. The vedges sliding von'the drum surface are arranged, here to'o, in such a manner that at any time several such edges slide upon the piston surface,'and secure a multiple line seal. vOtherwise the construction'of the vanes in FigsfS to l2 corresponds to that of Fig. 3. In the Figs. 9 to 12 for theisake of .simplicity merelythatfpart is'shown which in Fig. 8 is enclosed in a chain-'dotted frame.

The advantageof the embodiment according to the `Figs. 8 to l2 consists in that the lubricant is particularly well retained ybetween'the'drurn surface and the sealing facesv of the inserts, and is thrown off merely in small quantities owing .to pressure ydifferences. between `two adjacent compartments.

It may moreover be of advantage :from the`point of tionasmall play. 'The sealing between the frontal face of the drum and the bearing lid 15 can be attained then by vmeans of a frusto-conicahpiston ring which slotted atV one point, preferably onthe suction side. "Such an embodiment is diagrammatically illustrated in Fig. 6.

AAThe drum 10 has on Vthe side facing the bearing lid 15 vthey extend into the grooves of the closurel lids'and seal-up there. vMoreover it -canbe advantageous to construct the vanes in two or more.v parts in thedirection of rotation of the casinggthe partsof thevanesabutting on one another, andopposite end portions of part-vanes ea'ch being rigidly connected with one another by means of a bridge. An embodiment with subdivision of the vanes inthe direction of rotation of the casing is illustrated in Fig. 7.

Tlie components

8, 9 and 10 correspond to the same componetsin Figs. l and 2. The cylindrical casing 14 has two closure lids 16a and 16h. Each vane is subdivided in the Aaxial direction into two

parts

24a, 24b and 26a, 26b, respectively, the associated parts abutting on one another. Each two diametrically opposite vanes are rigidly connected to one another by means of the four

rings

32a, 33a, 32h, and 33h, respectively.

From the eccentricity between drum and casing on the one hand, and the rigid connection between two diametrically opposite vanes provided with the inserts on the other hand it results that the profile of the drum must deviate slightly from the circular shape, if a faultless seal, particularly practically an area seal or a multiple line seal, respectively is to exist between the inserts and the drum surface in any position of the casing. In the embodiment according to Fig. 2 for example the horizontal drum diameter Db is slightly larger than the vertical drum diameter Da. The difference between these two magnitudes Da and Db is, however, so small that it does not find any expression in the drawing. The particularly convenient shape of the drum proiile results in connection with the eccentricity between drum and casing and the selected shape of the sealing face of the inserts. By this mutual adaptation practically in any position of the vanes a faultless seal between the compartments is attained. From the foregoing considerations it follows also that the curvature of the drum surface is not constant and that consequently with given conditions of curvature of the sealing faces of the inserts a varying play between these sealing faces and the drum surface results upon rotation of the casing. In order to secure as extensive as possible an area seal or a multiple line seal, respectively, it is of advantage, to shape the seal faces of the inserts and the drum surface in such a manner, that at a given distance of two vanes lying diametrically opposite to one another the said play, i. e. the deviation between the sealing face and the drum surface is as a maximum of such a dimension that it can be compensated by the iilm of lubricant. It is clear that as good as possible an adaptation of the two faces, namely of the sealing face of the inserts on the one hand,

-and of the drum surface on the other hand, can be attained by various measures. For example` the inserts could be given a certain curvature, say a circular curvature. Then the optimum profile of the drum can be ascertained by calculation or empirically. With a circular curvature of the sealing faces of the inserts, that is with a constant radius of curvature thereof, two limiting cases can be distinguished. The radius of the sealing face may be at least equal to the largest radius of the curvature of the drum surface, or the radius of the sealing faces may correspond as a maximum to the smallest radius of curvature of the drum surface. Therefrom result-in exaggerated representationthe embodiments illustrated in the Figs. 13 and 14. In Fig. 13 the radius of curvature of the sealing face 51 of the insert 50 is smaller than the radius of curvature of the drum 10. In this case the end portions of the sealing faces 51 slide on the drum surface. In the embodiment according to the Fig. 14 the radius of curvature of the sealing face 51 is larger than that of the drum surface, i. e. substantially the middle portions of the sealing face 51 slide upon the drum surface. Quite generally the conditions can be so selected, that when the radius of curvature of the sealing face of the inserts is not constant, the largest radius of curvature of the sealing faces of the inserts is a maximum as large as the smallest radius of curvature of the drum surface, or that the smallest radius of curvature of the sealing faces of the inserts is at least as large as the largest radius of curvature of the drum surface.

Finally it should be mentioned that it is advantageous Vto let the inserts slightly protrude beyond the end margins of the vanes as will be seen particularly in Figs. 3 to 5. Thereby it can be attained that, at least over the better part of a revolution, the sealing faces of the inserts only keep in contact with the drum surface, and not parts of the vanes, themselves. p

The manner of operation of the rotary machine as illustration in the Figs. 1 and 2 and described hereinabove is as follows:

The cylindrical casing 14 may be-driven from a belt pulley mounted on the hollow shaft 18, or directly. Alternatively it may be coupled directly, lin certain circumstances without the use of packing glands, to the driving motor (not shown). From Fig. 2 it will be seen that the space between the drum 10 and the casing 14 is subdivided by four vanes 24, Z5, 26, 27 or by their

inserts

28, 2,9, 30, 31, respectively, into four compartments, the capacities of which periodically increase and diminish upon rotation of the casing. Through the conduit 11 air, for example, is aspirated. The same is compressed in the compartments, and expelled through the conduit 12; As perfect as possible a sealing of the compartments with respect to one another is secured by the construction of the vanes and their inserts, respectively, according to the invention. The rotary machine can be used as a circulation or feeder pump, compressor, blower, gearing, and also as a vacuum pump, as an engine or the like.

The machine according to the embodiment illustrated moreover offers the following advantages: the area sealing or at least multiple line sealing between the sealing faces of the inserts and the drum surface lsecures a faultless seal between the various compartments. This kind of seal allows to let the drum proper not to contact tightly on the cylindrical casing so that the space between the drum and the casing has in cross section not |the shape of a crescent but of a closed ring, contracting at the lowest point. Thereby any friction between the drum and the rotating casing is completely obviated. A further advantage results from the rigid connection of any two di-ametrically opposite vanes, since thereby the centrifugal forces of two diametrically opposite vanes in respect of the drum surface are cancelling out one another. Thi-s makes sure that the vanes of sealing faces of their inserts, respectively, always contact the drum surface and slide upon the same. It is remarkable, that the rotary machine of the construction described, operates noiselessly and free from vibrations, and that oil separators are not required. Besides, the width of the vanes and of the inserts, respectively, depends on the purpose for which the machine is to be used. With machines for comparatively high pressures, e. g. compressors, the width of the vanes and inserts, respectively, will have to be chosen in general larger than with machines for comparatively small pressures, e. g. blowers circulation pumps etc. Tests have proved, that with compressors and similar machines vanes and inserts, respectively, have -been found particularly favourable, the width of whichis at least equalto their stroke. In order to render also the movement of the vanes sliding in rthe grooves of the casing upon rotation as friction-less as possible, the vanes can be supported in the grooves on rollers, for example on comparatively largemachines.

In the embodiment illustrated and described, the oil conduits are so arranged that with a gaseous or vapourous medium, that is a medium of lower specic weight than the oil, upon rotation a separation of the oil takes place in the machine itself owing to centrifugal force, so that the medium is not contaminated by the oil.

While I have herein described and illustrated in the accompanying drawings what may be considered a typical and particularly usefull embodiment of my said invention, I wish it to be understood that I do not limit myself to the particular details and dimensions described and illus- Itrated, for obvious modications will occur to a person skilled in the art.

What I claim as my invention and desire to secure by Letters Patent, is:

1. A rotary machine, comprising in combination: a

st ationaryouter mantle, a-{closure lid lfixedly attachedv to the said mantle, a rotatable casing arranged insidethe said-mantleandjournalled-therein and in the said closure lid,-a -guide-.drum stationarily secured to said mantle and arranged inside the said rotatable casing `eccentrically with clearance from the inner wall ysurface thereof even at ythe :nearest point, shaft portions extending axially from `broth ends of the saidstationary drum through the said rotatable casing, au `'inlet duct land a discharge duct being provided jin thesaid shaft portions and communicatingrwith -an inlet part and a discharge part, respectively, issuing fromsaid drum intol the eccentrical annular space betweenthe said rotatable casing and statignary -drurnat -the points of maximum and minimum clearances, respectively, Vat least one pair of diametrically oppositie vanes slidably. guided in radial slots in the inner circumference of the said rotatable casing, a bridge piece foreach pair of vanes, said bridge pieces rigidly connecting the yanesof the co-ordin'ate pairs, respectively, with one 'another andgoing with ample clearance round the adjacent shaft r`portion extending from said stationary drum, and inserts fulcrume'd in the end faces of the said vanesfor rocking motions about axes parallel to the axis ofthe said rotatable casing andcontacting the circumference ofthe said drum, the said eccentrical annular space being divided into separate compartments sealed from one another by theisaid sliding varies and inserts thereof, and, upon rotation of the said casing iirstly increasing in volume from the said inlet part onwards, and then decreasing in volume towards the said discharge part, the said drum havingl a substantially elliptical cross `sectionwith the major axis at right'angles to the eccentrical offset of the said stationary drum with respect to the said rotary casing andthe sealing faces of the said inserts contacting the surface of the said stationary drum in any position at least with a multiple line contact, the gap between the said sealingfaces andthe surface of Vthe drum being everywhere smaller than the Kthickness of theV film ofllubricant applied to it.

2. A rotary machineas claimed in claim l, wherein the Said bridge pieces establishing the said rigid connection between diametrical opposite varies have an aperture surroundingv the said shaft portion the diameter of which exceeds the diameter of the said shaft portion so much' that `the`center of said vaperture coincides'with the axisof the said drum. u 3. A rotary"machine as claimed in claim l, wherein the said inserts protrudeat least partly beyond the end "faces'of the said vanes facing towards the said drum.

"4. A rotary machine las'claimed in claim vl, wherein 'ytliesealing faces of the said inserts sliding upon the said idr'u'm "Contact the surface "of the said drum practically withfan area contact.

5,"A`rotary machine 'as claimed in claim l, wherein recesses parallel to'the axis of rocking are provided in Y 8 Y thesealing faces of the said inserts contacting the surface` of the said stationary-drum.

6. A rotary machine as claimed in kclaim il, `wher-ein the ratio of4 the offset ofthe centers of the sai'dv casing and drum to .half the 'distance between 'diamet'rically opposite vanes :does 'not exceed 0.2.

l ing upon the said elliptical drum is adapted to the smallest curvature of the surface thereof, and wherein the circumferential width of the said inserts is so selected that the radial gap formed between the said inserts and the'surface of said drum at the points of greatest curvature is narrower than the thickness of the said film of lubricant.

'8. A rotary machine as claimed in claim l, wherein the width of the said vanes and inserts thereof is at least equal to the full length of the radial sliding movement thereof.

9. A rotary machine as claimed in claim 1, wherein the width of the said Vanes and inserts thereof is Smaller than the -full length of the radial sliding movement thereof. A

10. A rotary/'machine as claimed in claim 1 wherein ducts are provided in the said casing putting the spaces in the said casing outside the said vanes into a pressure compensating communication with one another.

1l. A rotary machine as claimed in claim 1 wherein the said vanes are subdivided in the axial direction of the said casing into at Ileast two sections abutting on one another, `each two diametrically opposite sections being rigidly connected with one another.

l2. A rotary machine as claimed in claim 1, wherein further means are provided for sealing said space between saidfdrum and said casing, said means comprising at least one resilient conicalrring, at least one end face of the said drum facing the adjacent inner end face of the said casing being conically recessed, said ring being fitted into said recessed face and slotted adjacent the portion of the said eccentrical annular space in communication with the said inlet part.

13. A rotary machine as claimed in claim 1 having ducts for the flubricant arranged in the 'said shaft portions, stationary drum, inserts, vanes and rotatable casing tapped at the largest radius of the said casing whereby thelubricant is separated from a pumped medium of lower'specilic weight by centrifugal force.

References Cited in the le of this patent UNITED STATES PATENTS