EP1329263B2 - Rotor with cavities for receiving a product for centrifuging and corresponding centrifuge - Google Patents

Description

The present invention relates to a centrifuge according to the preamble of claim 1. Such centrifuges are known from the state of the art.

The invention applies, for example, to the centrifugation of biological products.

For the centrifugation of such products, generally frustoconical shaped rotors in which the housings have been formed in the form of recesses. These housings have elongated shapes and are, for each rotor, regularly distributed around its axis of rotation. These housings are intended to receive, for example, tubes containing the products to be centrifuged and closed by plugs. The document JP-A-09262503 , US 6,045,494 and JP-A-0926 2503 describe rotors with a particular housing arrangement.

A centrifuge using such a rotor generally comprises a vessel, provided with refrigeration means and wherein the rotor is mounted on a rotating drive head.

It has been found in the ultracentrifuges, ie the centrifuges driving the rotors at speeds of the order of 20000rpm, the appearance of noise such as hissing.

An object of the invention is to solve this problem by limiting the noise caused by the rotational drive of rotors of the aforementioned type.

For this purpose, the subject of the invention is a centrifuge according to claim 1.

According to particular embodiments, the centrifuge may comprise one or more of the features of the dependent claims.

• la figure 1 est une vue schématique latérale d'une centrifugeuse,
• la figure 2 est une vue schématique du dessus du rotor de la figure 1,
• les figures 3 et 4 sont des vues analogues à la figure 2 illustrant respectivement un deuxième et un troisième modes de réalisation du rotor,
• la figure 5 est une vue schématique, agrandie et en coupe du rotor de la figure 4, prise suivant la ligne brisée V-V,
• la figure 6 est une vue analogue à la figure 5 illustrant un quatrième mode de réalisation du rotor,
• la figure 7 est une vue analogue à la figure 2 illustrant un cinquième mode de réalisation du rotor, et
• la figure 8 est une vue analogue à la figure 5 illustrant un sixième mode de réalisation du rotor.

Les figures ne représentent pas isolément des modes de réalisation de l'invention.The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

• the figure 1 is a schematic side view of a centrifuge,
• the figure 2 is a schematic view of the top of the rotor of the figure 1 ,
• the Figures 3 and 4 are similar views to the figure 2 respectively illustrating second and third embodiments of the rotor,
• the figure 5 is a schematic view, enlarged and in section of the rotor of the figure 4 , taken along the broken line VV,
• the figure 6 is a view similar to the figure 5 illustrating a fourth embodiment of the rotor,
• the figure 7 is a view similar to the figure 2 illustrating a fifth embodiment of the rotor, and
• the figure 8 is a view similar to the figure 5 illustrating a sixth embodiment of the rotor.

The figures do not represent in isolation embodiments of the invention.

The Figures 1 and 2 schematically illustrate a centrifuge 1 which comprises a vessel 2, a rotor 3 disposed in the vessel 2, and means 4 for driving the rotor 3 in rotation about a substantially vertical axis of rotation A.

In a conventional manner, the tank 2 comprises a mobile access door 6 and means of refrigerating its interior atmosphere, which refrigeration means are not shown in the figures.

The rotor 3 is a generally frustoconical rotor of central axis A. It is equipped with a removable closure cover 7. The lid 7 has not been shown on the figure 2 .

The rotor 3 is for example made of metal and four eccentric housings with respect to the axis A are formed, namely a first pair of housing 8 ₁ and 8 ₂ and a second pair of housing 10 ₁ and 10 ₂ . It will be noted that the housings 10 ₁ and 10 ₂ are not represented on the figure 1 .

The housings 8 ₁ and 8 ₂ of the first pair are symmetrical to each other with respect to the axis A. The housings 10 ₁ and 10 ₂ of the second pair are symmetrical to each other relative to each other. to axis A.

The housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ have an elongated similar shape along a respective longitudinal direction D.

As we see on the figure 1 for the housings 8 ₁ and 8 ₂ , each direction D is inclined with respect to the axis of rotation A and the section at a geometrical point situated above the rotor 3 and its cover 7.

The housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ open into the upper surface 12 of the rotor to allow, when the lid 7 is removed, to introduce into the housing containers containing the product or products to be centrifuged, for example tubes closed by plugs.

On the figure 1 the distance between the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ of the outer lateral surface 14 of the rotor 3 has been exaggerated to facilitate the representation.

As we see on the figure 2 The distribution of housings 8 ₁ August _2, 10 ₁ and 10 ₂ around the axis of rotation A is irregular.

Ainsi, l'image géométrique I (en trait mixte à double tiret) du logement 8₁ par une telle rotation dans un premier sens S₁ serait confondue avec le logement 10₁, logement qui suit directement le logement 8₁ dans ce sens S₁.If such a distribution were regular, the rotor 3 would be invariant by a geometric rotation of axis A and angle equal to 90 ° $\left(\frac{\mathrm{<figure-callout\; id="2"\; label="\pi "\; filenames="imgf0001.png"\; state="\{\{state\}\}">\pi </figure-callout>}}{2}\mathrm{r}\mathrm{at}\mathrm{d}\right)\mathrm{.}$

Thus, the geometric image I (dashed double dashed line) of the housing 8 ₁ by such a rotation in a first direction S ₁ would be merged with the housing 10 ₁ , housing directly following the housing 8 ₁ in this direction S ₁ .

In the rotor of Figures 1 and 2 the housing 10 ₁ is not confused with this image I but is, in plan view, angularly offset from this image I by a non-zero angle α centered on the axis A and negative with respect to the direction S ₁ .

In other words, the housing 10 ₁ is the image, by a geometric rotation of axis A and angle α, of the image I.

Thus, the longitudinal directions D of the housings 10 ₁ and of the image I form in plan view an angle α centered on the axis A and negative considering the direction S ₁ .

The angle α is for example 4 ° and may be more generally between 2 ° and 10 °.

It will be noted that on the figure 2 , the amplitude of the angle α has been exaggerated to facilitate the representation.

Similarly, the housing 10 ₂ is angularly offset, in top view, of the not shown frame of the housing 8 ₂ with the aforementioned rotation.

comme dans l'état de la technique.Thus, the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ are invariant by a geometric rotation of axis A and angle equal to 180 ° π rad) but not by a rotation of axis A and angle of 90 ° $\left(\frac{\mathrm{<figure-callout\; id="2"\; label="\pi "\; filenames="imgf0001.png"\; state="\{\{state\}\}">\pi </figure-callout>}}{2}\mathrm{r}\mathrm{at}\mathrm{d}\right)$

as in the state of the art.

It has been found, when rotating the rotor 3 at relatively high speeds, typically greater than 10000 rpm, that noise such as whistling is greatly reduced or suppressed.

It is currently estimated that the reason for this decrease or removal of noise may be as follows. When the rotor 3 is rotated, the zones Z ( figure 1 ) of the outer lateral surface 14 of the rotor 3 situated radially facing the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ are deformed, under the effect of the centrifugal force, radially outwards more strongly than the zones of the outer lateral surface 14 located between the housing. The reliefs thus created on the surface 14 are, like the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ , invariant by a geometric rotation of axis A and angle equal to 180 ° (π rad), and not by a geometric rotation of axis A and angle equal to 90 ° as in the state of the art. Thus, the frequencies and intensities of the acoustic waves created during the rotational drive of the rotor are modified and the noise is reduced or eliminated.

In addition, the unbalance caused by the irregularity of disposition of the dwellings is relatively weak and acceptable because α is relatively small.

According to a variant of the embodiment of Figures 1 and 2 , the angle α can be positive with respect to the direction S ₁ .

More generally, other arrangements of the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ are conceivable.

So, in the embodiment of the figure 3 , the housing 10 ₁ is in top view translated laterally, with respect to the image I of the housing 8 ₁ , opposite to the direction S ₁ of a non-zero distance d . Thus the longitudinal directions D of the housing 10 ₁ and the image I of the housing 8 ₁ are substantially parallel and spaced laterally from one another.

The distance d is for example 2mm and may be more generally between 1 and 5mm.

It will be noted that on the figure 3 the distance d has been exaggerated.

As this distance is relatively small, the difference between the centrifugal forces at which the products received in the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ will be subjected will remain sufficiently small and acceptable for the homogeneity of the centrifugation treatment. Similarly, the unbalance caused by the irregularity of disposition remain acceptable.

According to a variant not shown, the housing 10 ₁ may be, in top view, laterally offset from the image I of the housing 8 ₁ in the direction S ₁ .

More generally, the housing 10 ₁ may be, in top view, derived from a geometric translation of the image I, the direction of this translation not being necessarily orthogonal to the direction D of the image I.

More generally, the housing 10 ₁ can be deduced from the image I of the housing 8 ₁ by a geometric transformation in a radial plane containing the axis of rotation A and the longitudinal direction D of the image I.

Thus, figures 4 and 5 illustrate a third embodiment in which the longitudinal direction D of the housing 10 ₁ is angularly offset by a non-zero angle β with respect to the longitudinal direction D of the image I in the abovementioned plane P ( figure 4 ). This plane P also contains the direction D of the housing 10 ₁ and corresponds to the right half-plane of the figure 5 . Thus, the housing 10 ₁ is the image, by a geometric rotation of angle β in the plane P, of the image I.

It will be noted that the angle β can be positive or negative. This angle β has for example a value of 4 ° and may be more generally between 2 ° and 10 °.

The figure 6 illustrates another embodiment in which the housing 10 ₁ is obtained from the image I by geometric translation of a substantially constant distance δ nonzero in the radial plane P. Thus the directions D of the housing 10 ₁ and the I image are substantially parallel and spaced from each other. The aforementioned translation may be such that the housing 10 ₁ is closer to or further from the outer lateral surface 14 than the image I.

It will be noted that Figures 5 and 6 the angle β and the distance δ have been exaggerated.

It will also be noted that the angle β or the distance δ are sufficiently small so that, on the one hand, the homogeneity of the centrifugation treatment experienced by products received in the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ is satisfactory and on the other hand the unbalances are reduced.

More generally, the above principles can be applied to rotors comprising any number of housings.

They can also be combined with each other for the same dwelling.

So, the figure 7 illustrates yet another embodiment where the housing 10 ₁ is the image by a geometric transformation of the image I, this geometric transformation comprising a geometric rotation and a geometric translation in the plane of the figure 7 which is orthogonal to the axis of rotation A.

More precisely, the rotation is a rotation of axis A and angle α.

Translation is a translation in the plane of the figure 7 a non-zero distance d in a direction that is not orthogonal to the direction D of the image I.

Combining a rotation and a translation in the geometric transformation allows the housing 10 ₁ remain sufficiently close to the I picture to limit the differences between the centrifugal force experienced by a product contained in the housing 10 ₁ and the centrifugation force of a product received in the housing 8 ₁ .

Thus, the homogeneity of the centrifugation treatment undergone by products received in the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ is increased. In addition, this combination reduces unbalance and the difference in appearance between a rotor incorporating the principles of the invention and a conventional rotor.

Similarly, the figure 8 illustrates another embodiment where the housing 10 ₁ is obtained from the image I by a geometric transformation comprising a geometric rotation and a geometric translation in the radial plane P which comprises the axis of rotation A and the longitudinal direction D of the image I.

More precisely, the rotation is a non-zero rotation of angle β and the translation a translation of a non-zero distance δ in a direction orthogonal to the axis A.

Here again, the combination of a translation and a rotation makes it possible to increase the homogeneity of the centrifugation treatment undergone by products received in the housings 8 ₁ , 8 ₂ , 10 ₁ and 10 ₂ , to limit unbalance and to reduce aesthetic discomfort.

More generally, the geometric transformation between the image I and the housing ₁ may comprise a translation and / or a rotation in a plane orthogonal to the axis of rotation A, and a translation and / or rotation in a radial plane containing axis A.

Also generally, translations and rotations described above can be applied, for example separately each to a respective pair of housing when the number of housing is even and strictly greater than 4.

permettra de limiter les balourds.Preferably, the housings are symmetrical in pairs with respect to the axis A. Thus, when the rotor 3 is provided with an even number n of housings, the rotor 3 will be invariant by a geometric rotation of axis A and of angle 180 ° which limits the unbalance. More generally, an invariance by a geometric rotation of axis A and angle strictly greater than $\frac{360°}{\mathrm{not}}$

will limit the unbalance.

To avoid the appearance of noise, there will always be at least one first housing whose geometric image, by a geometric rotation around the axis of rotation A and angle 360 / n ° in a direction of rotation, is distinct from a second housing of the rotor, this second housing directly following the first housing in the direction of rotation chosen.

Claims (3)

1. A centrifuge comprising a tank (2), a rotor (3) intended to be disposed in the tank (2) and means (4) for imparting rotating motion to the rotor (3) about a central axis of rotation (A) at speeds above 10,000 rpm, a number n of compartments (8₁, 8₂, 10₁, 10₂) being provided inside the rotor for receiving a product to be centrifuged, the compartments being offset in relation to the axis of rotation, characterized in that the geometrical image (I) of at least one first compartment (8₁), by geometrical rotation about the axis of rotation (A) in a first direction of rotation (S₁) and by an angle $\frac{360°}{\mathrm{n}},$

   

   is distinct from a second compartment (10₁) which directly follows the first compartment (8₁) in the first direction of rotation (S₁), that the compartments (8₁, 8₂, 10₁, 10₂) are of substantially analogous elongated shape in a respective longitudinal direction (D), and that the second compartment (10₁) is substantially the image by geometrical transformation of the geometrical image (I) of the first compartment (8₁), that the geometrical transformation comprises:

   - a geometrical rotation by an angle (α) which is not zero in a plane perpendicular to the axis of rotation (A), and/or

   - a geometrical translation by a distance (d) which is not zero in a plane perpendicular to the axis of rotation (A), the direction of this translation being inclined in relation to the longitudinal direction (D) of the geometrical image (I) of the first compartment,

   and that the geometrical transformation further comprises:

   - a geometrical rotation by an angle (β) which is not zero in a plane containing the axis of rotation (A) and the longitudinal direction of the geometrical image (I) of the first compartment (8₁), and/or

   - a geometrical translation by a distance (δ) which is not zero in a plane containing the axis of rotation (A) and the longitudinal direction (D) of the geometrical image (I) of the first compartment (8₁).
2. A centrifuge according to claim 1, characterized in that the compartments (8₁, 8₂, 10₁, 10₂) are invariant by a geometrical rotation about the axis of rotation and by an angle strictly greater than $\frac{360°}{\mathrm{n}}\mathrm{.}$

   
3. A centrifuge according to claim 2, characterized in that n is an even number higher than or equal to 4 and the compartments (8₁, 8₂, 10₁, 10₂) are symmetrical in pairs in relation to the axis of rotation (A).

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