Patent Grant
10427170
This application claims the benefit of the German patent application No. 10 2015 119 616.6 filed on Nov. 13, 2015, the entire disclosures of which are incorporated herein by way of reference.
The present invention relates to a rotor of a centrifugal separator, the rotor having a central shaft on which a plate stack made up of a plurality of plates is situated in axially movable fashion, a stack base being situated on the shaft under the plate stack, a stack cap being situated in axially movable fashion on the shaft over the plate stack, and the rotor having a compression spring surrounding the shaft whose first end is supported on the shaft and whose second end is supported on the stack cap, compressing the plate stack.
A rotor of the type named above is known from WO 2009/010248 A2. In this known rotor, the second end of the compression spring presses on the top side of the stack cap. So that the compression spring can be situated on the shaft, the shaft has to extend past the stack cap by at least the tensioned length of the compression spring. Disadvantageously, this part of the shaft is then not available to accommodate plates of the plate stack.
An object therefore arises for the present invention of providing a rotor of the type described above that, having the same outer constructive size, has a larger number of plates in the plate stack without having to modify the plates for this purpose.
According to the present invention, this object is achieved by a rotor of the type described above that is characterized in that a sleeve-shaped extension that surrounds the shaft at a distance and extends into the plate stack is situated on the stack cap, and that the compression spring is situated inside the extension at least over the greater part of its axial length, and that a support surface for the second end, at the side of the stack cap, of the compression spring is situated on a base of the extension.
With the present invention, it is advantageously achieved that no additional axial constructive space is required for the situation of the compression spring, because according to the present invention the compression spring lies within the plate stack over the greater part of its axial length, or even over its entire axial length. As a result, the constructive space previously required for the segment of the shaft extending past the stack cap and bearing the compression spring can now also be used to situate plates of the plate stack. In this way, the number of plates in the plate stack can be significantly increased without enlarging the constructive space and without modifying the individual plates, bringing about a corresponding increase in the separating performance of the rotor, or of the centrifugal separator equipped with the rotor.
For reasons of good durability and economical mass production, the stack cap and the sleeve-shaped extension are preferably made in one piece with each other. Alternatively, the stack cap and the sleeve-shaped extension can also be made of two individual parts connected to one another.
In a further embodiment of the rotor according to the present invention, it is preferably provided that the shaft is made of metal and is surrounded by a rotationally fixed cladding made of plastic, the cladding having on its outer circumference an engagement contour for a rotationally fixed, axially movable engagement with a counter-engagement contour on the inner circumference of the plate of the plate stack. The metallic shaft supplies the required stability for the rotor. The contours required for the interaction of the various parts of the rotor can advantageously simply be made on the cladding, because the cladding is made of easily shaped plastic, e.g., thermoplastic or thermosetting plastic.
It is further proposed that the cladding be made on its outer circumference with a toothing made up of teeth running in the axial direction of the shaft, and that the plates of the plate stack are made having a mating counter-toothing on their inner circumference. These contours are easy to produce and reliably provide the desired rotationally fixed but axially movable engagement between the cladding and the plate stack.
A development of the rotor provides that the cladding has, on its end region facing the stack cap, an engagement contour for a rotationally fixed, axially movable engagement with a counter-engagement contour on the sleeve-shaped extension of the stack cap. In this way, a situation of the stack cap of the rotor is achieved that is rotationally fixed relative to the cladding but is axially movable.
In a further embodiment, it is preferably provided that the cladding is fashioned, in its end region facing the stack cap, with a toothing made up of teeth running in the axial direction of the shaft, and that the sleeve-shaped extension of the stack cap is made with a mating counter-toothing.
In order to make it possible to situate the plates in rotationally fixed and axially movable fashion inside the rotor in its region situated close to the stack cap as well, it is preferably provided that the sleeve-shaped continuation of the stack cap has on its outer circumference an engagement contour for a rotationally fixed, axially movable engagement with a counter-engagement contour on the inner circumference of the plates of the plate stack.
So that identical plates can be used within the rotor for the plate stack, and so that the plates can be easily mounted, the engagement contours provided for the plates on the extension of the stack cap and on the cladding are usefully identical to one another and made continuously connected to one another.
In particular, for the purpose of a simple, low-cost, and reliable production, the present invention further provides that the cladding is injection-molded onto the shaft. In this way, it is reliably ensured that the cladding is seated on the shaft in a rotationally fixed fashion.
Also, for reasons of simple and low-cost production and easy assembly of the rotor, the stack base and the cladding are usefully made in one piece with one another. In this way, in a simple and reliable manner the stack base is also configured so as to be rotationally fixed and axially fixed relative to the shaft.
As mentioned above, the compression spring is supported with its first end on the shaft; this supporting can be immediate or indirect. Preferably, the compression spring is supported with its first end, pointing away from the stack cap, on a radially protruding collar of the shaft or on a ring that is axially fixedly connected to the shaft, such as a snap ring, thus achieving a very compact construction.
A development of the rotor according to the present invention is characterized in that between the first end of the compression spring on the one hand, and the collar or ring on the other hand, there is situated an intermediate body, and that the stack cap has an axially outer collar radially outwardly surrounding the intermediate body, the collar being axially displaceable in sealing fashion relative to the intermediate body. In this way, undesired erroneous flows of the fluid medium (that is to be cleaned and is flowing through the rotor) out of the rotor through the sleeve-shaped extension and the stack cap are prevented.
In a further embodiment of the rotor according to the present invention, it is provided that the shaft, seen in its axial direction, is made up of two shaft parts, a first shaft part, which provides a rotatable mounting of the rotor, being made of metal, and a second shaft part, bearing the plate stack, being made of plastic and being connected in rotationally fixed and axially fixed fashion to the first shaft part, and the second shaft part having on its outer circumference an engagement contour for a rotationally fixed, axially movable engagement with a counter-engagement contour on the inner circumference of the plate of the plate stack. Advantageously, in this way the metallic part of the shaft, and thus the weight of the shaft, is reduced, and a greater degree of shaping freedom is enabled with respect to the shaping of the second shaft part.
In order to make it possible to securely situate the plates of the plate stack on the second shaft part, with a simple shaping, it is proposed that the second shaft part is made with a toothing on its outer circumference made up of teeth running in the axial direction of the second shaft part, and that the plates of the plate stack are made on their inner circumference with a mating counter-toothing.
In a further embodiment, it is provided that the second shaft part has, on its end region facing the stack cap, an engagement contour for a rotationally fixed, axially movable engagement with a counter-engagement contour on the sleeve-shaped extension of the stack cap. In this way, via the sleeve-shaped extension of the stack cap, the plate stack can be pressed together in a desired manner, thus avoiding an undesirable rotation of the stack cap with the extension relative to the second shaft part.
A further embodiment in this regard provides that the second shaft part is made, in its end region facing the stack cap, with a toothing made up of teeth running in the axial direction of the shaft, and that the sleeve-shaped extension of the stack cap is made with a mating counter-toothing. In this way, reliable functioning is achieved with a simple shaping of the engagement contour and counter-engagement contour.
So that the sleeve-shaped extension of the stack cap can also be used for the situation of plates of the plate stack, it is proposed that the sleeve-shaped extension of the stack cap has on its outer circumference an engagement contour for a rotationally fixed, axially movable engagement with a counter-engagement contour on the inner circumference of the plates of the plate stack.
Preferably, here the engagement contours on the extension and on the second shaft part for the plates are made identical to one another and continuously connected to one another. In this way, inside the rotor identical plates can be used for the plate stack regardless of whether a plate is situated on the extension or on the second shaft part.
In order to ensure a good and permanent connection between the two shaft parts, the second shaft part is usefully injection-molded onto the first shaft part.
Also for reasons of a permanent secure connection, as well as low-cost production, the stack base and the second shaft part are preferably made in one piece with one another.
Due to the fact that the second shaft part is made of plastic, as mentioned above, this part can be made more freely with regard to its shape. An advantageous embodiment in this regard provides that the compression spring is supported with its first end, pointing away from the stack cap, on radially protruding supporting lugs of spring bearing arms that form a part of the second shaft part and that run axially and are radially springy. A separate ring to be connected in axially fixed fashion to the shaft, such as a snap ring, is here not required for the supporting of the first end, pointing away from the stack cap, of the compression spring. During the assembly of the rotor, it is sufficient to slide the compression spring over the radially protruding support lugs of the axially running, radially springy spring bearing arms, pushing in the spring bearing arms in the direction toward the base of the extension of the stack cap, until the spring bearing arms spring out again, and the compression spring is then supported with its first end pointing away from the stack cap on the radially protruding support lugs of the springy spring support arms.
Finally, for the rotor according to the present invention, it is provided that the plates, the stack base, and the stack cap are injection-molded parts made of plastic. In this way, the named parts of the rotor can be easily produced at low cost as mass-produced parts, simultaneously achieving an advantageously low weight of the rotor.
In the following, an exemplary embodiment of the present invention is explained on the basis of a drawing.
In the following description of the Figures, identical parts in the various figures are always provided with the same reference characters, so that all reference characters do not have to be explained again for each Figure.
In the axially center region in
A plate stack 2 that is made up of a multiplicity of plates, not shown individually here, is set onto base 6 from above, and lies with its lower side on support surface 32 of stack base 3.
At its upper side, plate stack 2 is covered by a stack cap 4 that lies on the upper side of plate stack 2 with a lower-side support surface 40. Stack cap 4 has, radially inwardly, a sleeve-shaped extension 41 that extends into plate stack 2 and that surrounds shaft 11 at a distance. A base of extension 41 has an opening through which shaft 11 is guided.
In the interior of extension 41 there is situated a compression spring 5, in the form of a helical spring. With its first, upper end, compression spring 5 is supported on an intermediate body 7 that, for its part, is axially supported by a ring 15 close to the upper, free end 12 of shaft 11. Second, lower end 52 of compression spring 5 is supported on a support surface 45 that is formed by the upper side of the base of extension 41.
Through the force of compression spring 5, stack cap 4 is axially loaded in the direction toward stack base 3, so that stack base 3 and stack cap 4 clamp plate stack 2 between them, and stabilize it in its shape. The adjacent plates of plate stack 2 form, in a known manner, flat gap spaces between them, through which, during operation of rotor 1, there flows the gas that is to be freed of particles that it carries along. In a likewise known manner, the plates of plate stack 2 each have the form of a frustum-shaped cladding having an inclined radially outer part and a flat radially inner part, as is explained in more detail below on the basis of
Due to the fact that here compression spring 5 is situated over its entire length inside sleeve-shaped extension 41, almost the entire axial height of shaft 11 above stack base 3 can be used to situate plate stack 2. Advantageously, an upper part of shaft 11 does not extend relatively far past stack cap 4 for the situation of compression spring 5. In this way, with the same axial constructive height of rotor 1, a plate stack 2 having a significantly larger number of plates can be accommodated.
On the lower side of stack base 3, concentrically to one another, there are integrally formed an inner sleeve-shaped extension 33 and a radially external sleeve-shaped extension 34. In a radially inner region of stack base 3, distributed over its circumference, inlet openings 31 are situated between extensions 33, 34, through which openings a gas that is to be freed of liquid or solid particles, for example crank case ventilation gas of an internal combustion engine, can enter into plate stack 2 during operation of rotor 1. The gas is then diverted outwardly in the radial direction into the gap spaces of plate stack 2, and exits plate stack 2 at its outer circumference. The particles carried along in the gas meet the inner surfaces of plate stack 2, and in this way are separated from the gas flow, and, as a result of the rotation of rotor 1, are deposited on the inner circumference of a separator housing (not shown here) that surrounds rotor 1 in a known manner during operation.
In order to prevent erroneous flows of the gas from plate stack 2 out of rotor 1 through the interior of sleeve-shaped extension 41, intermediate body 7 is sealed by a sealing ring 70 in a hollow cylindrical collar 47 integrally formed at the upper side on stack cap 4; here stack cap 4 can move, to a limited, adequate degree, in the axial direction of rotor 1 relative to intermediate body 7 supported on shaft 11, in order to accommodate tolerances or changes in the height of plate stack 2 occurring as a result of temperature.
In a region immediately below stack base 3, shaft 11 has a bearing surface 13 that is used for the situation of a plain bearing or roller bearing not shown separately here. In a part of shaft 11 situated further below, not shown here, there is situated a rotational drive having a suitable known design.
At bottom in
Above plate stack 2, stack cap 4 is shown, having, centrally in its interior, sleeve-shaped extension 41 extending in the direction toward plate stack 2. On its outer circumference, extension 41 has on the one hand an engagement contour 42 that is identical to engagement contour 62 on cladding 6 and that interacts with counter-engagement contour 22 of the plates of plate stack 2 when rotor 1 is assembled. On the other hand, extension 41 has on its outer circumference a counter-engagement contour 44 that, in the assembled state, interacts with an engagement contour 64 in the upper region of cladding 6, such that contours 44, 64 bring stack cap 4 into engagement with stack base 3 in rotationally fixed but axially movable fashion.
On its downward-pointing side, stack cap 4 has a support surface 40 for the upper side of plate stack 2. Here, spacer webs 43, running in the radial direction, are integrally formed on support surface 40, so that a gap that is effective for the separation is also formed between the upper side of plate stack 2 and the lower side of stack cap 4.
Hollow cylindrical collar 47 for accommodating intermediate body 7 is integrally formed at the upper side on stack cap 4.
Above stack cap 4, compression spring 5, in the form of the helical spring, is visible with its first, upper end 51 and its second, lower end 52. In the assembled state, upper end 51 of compression spring 5 is supported on the lower side of intermediate body 7, here shown above compression spring 5. In the assembled state, the second, lower end 52 of compression spring 5 is supported on support surface 45, which is formed by the upper side of a base of sleeve-shaped extension 41 of stack cap 4.
Intermediate body 7 essentially has the shape of a flat circular annular disc having a central opening, through which, in the assembled state, upper end 12 of central shaft 11 extends. Circumferential sealing ring 70, for example an O-ring, is situated radially outwardly on intermediate body 7.
Finally, all the way at the top in
Above stack base 3, cladding 6 is visible with its engagement contours 62, 64 for plate stack 2 and for stack cap 4. Upper end 12 of shaft 11, with groove 14 for ring 15, extends from cladding 6 at the top.
Above upper end 12 of shaft 11, plate stack 2 is shown as a further component, and here as well, for reasons of clarity, the individual plates of plate stack 2, which in practice are very thin, are not shown. On the inner circumference of plate stack 2, its counter-engagement contour 22 can be seen, which in the assembled state interacts with engagement contour 62 of cladding 6 and engagement contour 42 of extension 41 of stack cap 4 to hold plate stack 2 so as to be axially movable and rotationally fixed.
Above plate stack 2, stack cap 4 is shown, in whose interior sleeve-shaped extension 41 is situated. On the outer circumference of extension 41, engagement contour 42 for plate stack 2 and counter-engagement contour 44 for interaction with engagement contour 64 on cladding 6 are visible. Above support surface 40 of stack cap 4, which points downward in the direction toward plate stack 2, radial spacer webs 43 run with regular distances from one another, seen in the circumferential direction.
Above stack cap 4, compression spring 5 is visible with its first, upper end 51 and its second, lower end 52. Above this there follows intermediate body 7 with its outer circumferential sealing ring 70. Finally, all the way at the top in
As
Extension 41 has, on its outer circumference, engagement contour 42, formed by a toothing running in the longitudinal direction of extension 41, which toothing engages with counter-engagement contour 22 on the inner circumference of upper plates 20 of plate stack 2.
In addition, cladding 6 also has on its outer circumference an engagement contour 62 that is identical to and coincides with engagement contour 42 of extension 41, and which engages with counter-engagement contour 22 on the inner circumference of plates 20, situated further below, of plate stack 2.
So that no relative rotation can take place between extension 41 and cladding 6, cladding 6 has an engagement contour 64 that stands in engagement with an engagement contour 44 of extension 41.
All above-named engagement contours 42, 62, 64 and counter-engagement contours 22, 44 are fashioned such that the associated parts of rotor 1 are secured against rotation relative to one another, but are axially movable.
Differing in particular from the previously described exemplary embodiment here is the fact that central shaft 11 has a first, lower, metallic shaft part 11.1 and a second, upper, shaft part 11.2 made of plastic. Second shaft part 11.2 made of plastic is preferably injection-molded onto first, metallic shaft part 11.1. Metallic first shaft part 11.1 has two bearing surfaces 13 axially at a distance from one another, on which rotor 1 can be rotatably mounted inside a centrifugal separator by plain bearings or roller bearings.
Here as well, stack cap 4 has a sleeve-shaped extension 41, integrally formed in one piece, which extends into plate stack 2 and in which compression spring 5, for compressing plate stack 2, is situated between stack base 3 and stack cap 4. Here as well, compression spring 5 is supported with its lower end 52 on a support surface 45 formed by a base of extension 41. Here, differing from the first exemplary embodiment, upper end 51 of compression spring 5 is axially supported on a plurality of support lugs 17′ which are integrally formed on the free upper end of a plurality of spring bearer arms 17, configured in a circle, which are made in one piece with second shaft part 11.2 and are part of second shaft part 11.2. Compression spring 5 here surrounds the configuration of spring bearer arms 17, and support lugs 17′ point radially outward.
Thus, when installing rotor 1, it is sufficient to push compression spring 5 onto the configuration of spring bearer arms 17 from the top, after placing stack base 3, plate stack 2, and stack cap 4 onto shaft 11, spring bearer arms 17 being pushed flexibly inward in the radial direction until compression spring 5 has reached the position shown in
In order to make it possible to situate plates 20 of plate stack 2 on shaft 11 and on extension 41 in rotationally fixed fashion but so as to be axially movable, shaft 11 has engagement contour 16 in its second shaft part 11.2 on the outer circumference, and extension 41 has engagement contour 42 on its outer circumference, which contours engage with counter-engagement contour 22 on plates 20. Moreover, engagement contour 16′ on second shaft part 11.2 and counter-engagement contour 44 on sleeve-shaped extension 41 stand in engagement with one another.
With regard to the further individual parts of rotor 1 shown in
On second shaft part 11.2, engagement contours 16, 16′, spring bearer arms 17, and their support lugs 17′ are visible.
Above this,
For the installation of rotor 1, plate stack 2 is pushed in the axial direction onto the upper, second shaft part 11.2, producing the rotationally fixed but axially movable engagement. Subsequently, stack cap 4 is also placed onto second shaft part 11.2, producing the rotationally fixed but axially movable engagement. As the last step, compression spring 5 is placed from above onto spring bearer arms 17, which form a part of second shaft part 11.2, with their support lugs 17′, and is locked under tension, whereby stack cap 4 is loaded with a force in the direction towards stack base 3, and in this way plate stack 2 is axially compressed in the desired manner
Finally,
Second shaft part 11.2 has engagement contours 16, 16′, spring bearer arms 17, and support lugs 17′.
As in the previously described first exemplary embodiment, here as well stack base 3 has on its lower side a radially inner sleeve-shaped extension 33 and a radially outer sleeve-shaped extension 34. Moreover, here inlet openings 31 of stack base 3 are visible from below.
Further up in
Still further up in
As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2015 119 616 | Nov 2015 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/077213 | 11/10/2016 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2017/081124 | 5/18/2017 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 920481 | Kimball | May 1909 | A |
| 1928080 | Uebelacker | Sep 1933 | A |
| 3410481 | Dahlberg | Nov 1968 | A |
| 7674376 | Herman | Mar 2010 | B1 |
| 7731772 | Lagerstedt | Jun 2010 | B2 |
| 9074558 | Roelver | Jul 2015 | B2 |
| 20060100083 | Lagerstedt | May 2006 | A1 |
| 20100180854 | Baumann | Jul 2010 | A1 |
| 20110281712 | Schlamann | Nov 2011 | A1 |
| 20120174541 | Tornblom | Jul 2012 | A1 |
| 20120174546 | Tornblom | Jul 2012 | A1 |
| 20180318847 | Luersmann | Nov 2018 | A1 |
| Number | Date | Country |
|---|---|---|
| 202008014734 | Mar 2010 | DE |
| 157336 | Apr 1922 | GB |
| 2009010248 | Jan 2009 | WO |
| Entry |
|---|
| International Search Report, dated Mar. 2, 2017, priority document. |
| Number | Date | Country | |
|---|---|---|---|
| 20180318847 A1 | Nov 2018 | US |
