EP1268074B1 - Centrifuge having axially oriented separator surfaces - Google Patents

Abstract

The invention relates to an inset for a centrifuge rotor. The inset preferably consists of an inner tube (48) and an outer tube (50). Said inset can be perfectly fitted into the appurtenant centrifuge rotor by means of said tubes in such a way that the fluid is forced to flow through between separator surfaces (52) that are configured in a bent manner and are situated between the outer tube and the inner tube. Said surfaces result in an optimum separation of the particles by virtue of the bend thereof, said particles being in the fluid. Such an inset can especially be used in free jet centrifuges for cleaning lubricating oil of an internal combustion engine.

Description

State of the art

The invention relates to a centrifuge, in particular a free-jet centrifuge for cleaning lubricating oil of an internal combustion engine, having axially oriented deposition surfaces according to the preamble of claim 1. Furthermore, the invention relates an insert for such a centrifuge rotor, having said deposition surfaces according to the preamble of claim 5.

Such deposition surfaces for centrifuge rotors are for example from the WO00 / 23194 known. These deposit surfaces are in a replaceable insert arranged and should cause the dirt pickup of the fluid to be centrifuged. If such an insert is sufficiently loaded with particles, it can be replaced or to be cleaned. This is a particularly economical operation of the centrifuge rotors possible because when reaching the highest dirt holding capacity of the rotor only the insert needs to be changed. A centrifuge according to the The preamble of claim 1 is known from WO-A-9 951 353.

However, the known dirt receiving inserts so far provide no optimal result regarding the separation efficiency of the centrifuges. The stakes are not optimal adapted to the present in the centrifuge rotor flow conditions, which is why the Dirt particles are not completely removed from the fluid to be centrifuged can.

The object of the invention is therefore to provide a centrifuge with a rotor housed Use to provide optimal results in terms of deposited particles supplies. This object is solved by the features of claims 1 and 5.

Advantages of the invention

According to the invention an insert according to claim 1 or 5 is housed in the centrifuge rotor. All in all the insert can be flowed through axially, d. H. that the deposition surfaces so axially are arranged in use, that they have an axial or at least substantially axial Allow it to flow through.

The spiral arrangement of the deposition surfaces is thus to be understood that these with respect to a running through the axis of rotation of the rotor straight line an angle between 0 and 90 ° (0 ° would have an orientation as a radial rib and 90 ° mean a design as a peripheral wall).

As a result, an optimal separation is achieved because the described orientation of the Depositing surfaces for optimal acceleration of the particles to be separated by rotation of the rotor leads. The particles are passing through the concave surface of the deposition surfaces accelerated and on the convex surface of the adjacent deposition surface or deposited on the outer peripheral edge of the insert. The rotor must be replaced if the deposits have reached a level that the fluid no longer fast enough through the formed by the deposition surfaces Channels can flow.

According to a further embodiment of the invention, the deposition surfaces extend in a constant angle α to any, passing through the axis of rotation of the rotor Levels. This causes a steady acceleration of the fluid in the said channels of the mission achieved. A particularly good result in terms of deposition leaves reach when the angle α is 45 °. However, this includes depending on Case of application and the particle size does not mean that angles can be chosen, which deviate from the value of 45 °.

According to the invention, the use each an inner and outer tube. At this Pipes are attached to the deposition surfaces, leaving a more stable composite body arises. Due to the stability, the wall thickness of the individual walls can be minimized and thus the volume of the insert can be maximized, leaving that space for deposition of particles is available. The insert is with the Inner and outer tube installed in the rotor so that the insert with the outer tube supported in the rotor and the inner tube with the spindle of the housing, which supports the storage carries for the rotor, communicates with low friction. By that is meant that at this A narrow gap remains, resulting in easy rotatability of the rotor leads, but allows only a small side stream of the fluid to be centrifuged, so that this can be optimally centrifuged by the use. In principle, this is true also for a variant of the rotor, in which this itself has an inner tube, on the the inner tube of the insert is inserted. Here is no relative movement between the Inner tubes needed. Therefore, a particularly dense composite can be created.

Advantageously, the insert can furthermore be arranged replaceably in the rotor. In this way, only needs to be replaced when reaching the end of life become. Instead of a replacement is also a cleaning of the insert conceivable because the deposition surfaces are arranged easily accessible. The cleaning can z. B. by means of compressed air or by means of a cleaning jet along the axial deposition surfaces respectively.

Furthermore, the use described as such is under protection, which for the Use in a centrifuge rotor of the type described is suitable.

These and other features of preferred embodiments of the invention are excluded from the claims also from the description and the drawing, wherein the individual features in each case alone or in the form of sub-combinations realized in the embodiment of the invention and in other fields can be and represent advantageous and protectable versions for which protection is claimed here.

drawing

Figur 1

den schematischen Schnitt durch eine Freistrahlzentrifuge mit einem Rotor, in den ein Einsatz eingebaut ist,

Figur 2

den Querschnitt durch einen Einsatz gemäß Figur 1 und

Figur 3

die perspektivische Ansicht des Einsatzes.

Further details of the invention are described in the drawing with reference to schematic embodiments. Show here

FIG. 1

the schematic section through a free-jet centrifuge with a rotor, in which an insert is installed,

FIG. 2

the cross section through an insert according to Figure 1 and

FIG. 3

the perspective view of the insert.

Description of the embodiments

FIG. 1 shows a centrifuge 104 with a rotor 10. The housing 101 includes a spindle 12 on which the rotor is rotatably supported by means of bearing rings 16, 18. The spindle is further hollow, so that via an inlet 102 accordingly of the arrow 20, the fluid can penetrate through openings 22, 24 in the rotor 10. alternative For example, the rotor 10 may have a bearing tube which supports the bearing rings 16, 18 and separates the interior of the rotor from the spindle. In this bearing tube need additional Be provided openings for the passage of the fluid.

Furthermore, the rotor 10 comprises an outer wall 14. The outer wall 14 is to the spindle sealed, in which case the bearing rings 16, 18 are used. About these prevents the centrifuged liquid from the centrifuge rotor in larger Quantities in the housing exits.

The liquid enters through said openings 22, 24 in the centrifuge rotor. Normally, the liquid consists of the oil for an internal combustion engine.

Thus, the rotor 10 forms a chamber 30, which consists of the space between the bearing rings 16, 18 and the outer wall 14 results. Without any structure in the chamber 30, the fluid would take the path of least resistance. This path, as shown in calculations, extends along the spindle and behind an annular cutting disk 32 towards the drive chamber 33, which is located below the cutting disc. While the fluid follows this path, its rotation is but less than that of the centrifuge rotor. This is related to that in near the spindle acts a lower centrifugal force than on the outside of the Rotor. As a result, the particles to be separated have to travel a long distance, to get to the separation surface on the outer wall. This is especially true for free-jet centrifuges disadvantageous because the residence time of the fluid in these centrifuges due to the constant drive flow to the drive nozzles 38 is limited in time. Therefore, an effective deposition system must be used for free-jet centrifuge rotors be used. This is a prerequisite that the fluid is not without effectively build a filter cake in the centrifuge, unfiltered from the drive nozzles exit, then z. B. back to the oil pan of the engine flow.

Therefore, in the chamber 30, an insert 40 with Abscheideflächen (see Figure 2) housed. This is shown in Figure 1 only as an outline (dash-dotted lines). The use 40 extends from the spindle 12 (alternatively, but not shown, from the bearing tube) to an outer wall 14 of the insert. The insert also has an upper one End face 42 and a lower end face 44. Not necessary, but beneficial the end face 42 and the end face 44 parallel to each other and at right angles to the Axis of rotation 46 of the centrifuge. The insert is also designed so that it replaced can be. For this purpose, the centrifuge rotor 10 and the housing 101 openable executed (not shown). The insert is suitable for a large To collect the amount of particles in the fluid to be centrifuged. If this is his Limit capacity, this can either be thrown away and replaced by a new one Be replaced use or he will be cleaned and then reinstated. Since the Use has no bearing function, this can be from a cost effective Material to be made. This can be z. B. be plastic like nylon 66 This In addition, material has the advantage of low weight, reducing the inertia of the Centrifugal rotor is low and therefore the power of the drive nozzles to high speeds leads. In addition, plastic can be processed easily. Due to the simple structure the use of this z. B. be designed as an extruded profile and suitable be deflected to the corresponding centrifuge rotor.

In Figures 2 and 3, the insert is shown in more detail. This includes an inner tube 48 and an outer tube 50. The inner tube 48 is designed such that the diameter is substantially equal to the diameter of the spindle (not shown in Figure 1). This will be a Side flow of the liquid to be centrifuged outside the insert prevented. As a result, the fluid is forced through the one provided with the Abscheideflächen Use to flow. The insert thus effectively added to the zuzentrifugierende Fluid in the necessary for the deposition of the particles rotational movement. Independently the diameter of the entire fluid is thus exposed to the same centrifugal force. By the appropriate choice of the angle of the curved Abscheideflächen to each Diameter line that passes through the axis of rotation, the Abscheideweg and thus the time required for the fluid to remain in the rotor is greatly reduced.

The outer tube 50 has a diameter which is also substantially equal to the inner diameter of the outer wall 14 of the rotor. This can be seen in FIG become. The outer tube 50 is designed as a cylinder which is between extends the two end faces 42 and 44 of the insert. The insert is designed in such a way that the particles settled on the concave curved Abscheideflächen, wherein there is an additional tendency towards the outer diameter of the insert. This means that the insert is essentially from the outside inwards with the filter cake fills, as is already known from centrifuges according to the prior art.

FIGS. 2 and 3 further show that the insert has a larger number of Separation surfaces 52 includes. Each of these separation surfaces also extends from the upper end 42 to the lower end 44 of the insert. In addition, runs each of the separation surfaces between the inner tube 48 and the outer tube 50. Thus Each separation surface forms a guide surface, along which the particles in the zu centrifuging fluid to be deposited in use. there is a continuous course of the curvature of the separation surfaces of great advantage because the flow is the least disturbed in this way. Turbulence in the flow, which can have a negative impact on a deposit and on missions according to The prior art may be necessary in the described use completely be avoided.

The Abscheideflächen 52 are over the entire distance between the inner tube 48 and outer tube 50 curved. This is a constant angle of curvature over a Level, which leads through the axis of rotation, complied with. Preferred, as in this example, is the angle of curvature α = 45 ° (see Figure 2). Depending on parameters such as particle size, the viscosity of the fluid to be centrifuged and the residence time of the fluid in the centrifuge rotor, however, the optimal angle can be between 30 and 30 60 °. The design of the separation surfaces further ensures that nearby of the inner tube, where the lowest centrifugal force prevails, also the Abscheidweg for the particles are the least, since the distance between adjacent separation surfaces downsized to the inside of the insert.

Returning to Figure 1, it should be noted that the insert has a length X. These Length is given by the totality of the components of the insert, so the inner tube 48, the outer tube 50 and the entirety of the Abscheideflächen 52. The length X is smaller than the length Y of the outer wall of the rotor 10. As a result, in the rotor 10th Areas 54 forming the collection of the fluid in the rotor and a preliminary calming of the same. The areas 54 go steplessly into the outer wall 14 above. As a result, in the vicinity of the areas 54 already before entering the insert a concentration of the fluid take place with particles to be separated. This is ensures that the filter cake in use preferably builds up on the outer tube 50, to ensure its stability. Furthermore, it prevents this from happening uneven filter cake builds up so that the rotor is optimally balanced with the insert remains.

An alternative, not shown, also allows the accommodation of several Inserts in a rotor. As a result, once created a kind of modular system so that rotors of different capacity with a small number of different Inserts or even just one type of inserts can be formed. Furthermore an insert can be formed which includes fewer separation surfaces and the tasks of the areas 54 by the calming of the fluid takes over.

Claims (5)

1. Centrifuge, more especially free jet centrifuge for the filtering of lubricating oil of an internal combustion engine, said centrifuge including a rotor (10), which is rotatably mounted in a housing (101), having separation surfaces+ (52) for insert (40) which contains impurities and is traversable in an axial manner by the liquid to be filtered, wherein the separation surfaces are aligned in the insert in a spiral manner relative to the axis of rotation of the rotor, characterised in that the insert includes an outer tube (50), to which the separation surfaces are secured and from which they extend inwards and the insert includes an inner tube (48), to which the separation surfaces are secured and from which they extend outwards, and wherein with a small amount of friction the inner tube engages a spindle (12) of the housing for mounting the rotor and an outer wall (14) of the rotor is supported on the inside surface such that a stable composite body is formed.
2. Centrifuge according to claim 1, characterised in that the separation surfaces (52) include a constant angle α relative to arbitrary planes, which extend through the axis of rotation of the rotor (10).
3. Centrifuge according to claim 2, characterised in that the angle α is 45°.
4. Centrifuge according to one of the preceding claims, characterised in that the insert (40) is disposed so as to be replaceable in the rotor (10).
5. Insert (40) with separation surfaces (52) for a centrifugal rotor, wherein these separation surfaces are aligned in the insert in a spiral manner relative to the axis of rotation of the associated centrifugal rotor, characterised in that the insert includes an outer tube (50), to which the separation surfaces are secured and from which they extend inwards and the insert includes an inner tube (48), to which the separation surfaces are secured and from which they extend outwards, and wherein, when in use, the inner tube engages a spindle (12) of the housing with a small amount of friction for mounting the rotor and an outer wall (14) of the rotor is supported on the inside surface, such that a stable composite body is formed.

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