EP2199713B1 - Laboratory centrifuge - Google Patents

Description

The present invention relates to a laboratory centrifuge according to the preamble of claim 1.

The present invention relates to laboratory centrifuges, i. Centrifuges used, for example, in chemical, biological, biochemical or biotechnological laboratories. On the other hand, the present invention can be advantageously used in large-scale centrifuges and mechanical stirring devices and all devices in which a good is to be cooled at least indirectly.

In particular, the invention does not relate to cookware, frying pans or the like containers which serve to heat a good that can be arranged in the container.

Background of the invention

During centrifugation, heat is generated during the rotation of the centrifuge rotor in the centrifuge vessel due to air friction and electrical power loss. Since the centrifuge vessel is closed with a lid to prevent spillage of centrifuging, this heat input can not be easily dissipated and leads to an increase in the temperature of Zentrifugiergutes.
However, this temperature increase is usually undesirable. Therefore, precautions have been taken in the past to avoid an increase in centrifuging temperature. This can be done either by direct cooling or by indirect cooling by means of a heat exchanger principle. In the indirect cooling (indirect cooling) so there is no direct contact between the cooling medium and to be cooled Good or wrapping the goods to be cooled.

In direct cooling, the ambient air is passed directly through the centrifuge bowl at the centrifuge rotor, with the rotor acting as a kind of radial fan. For this purpose, the centrifuge lid and / or centrifuge bowl has an inlet opening near the axis and an outlet opening arranged at a distance from the axis of rotation. Although such direct cooling has proven itself, the centrifuge tank must have an outlet opening for it, which, however, also permits a material outlet. Such boilers are thus not suitable for stirring devices or the like, in which materials are to be mixed directly and must therefore be formed closed all around. A disadvantage of direct cooling results from the use of the ambient air as a coolant: the good can be cooled only to the maximum temperature of the ambient air.

In indirect cooling, the rotor is enclosed in the centrifuge vessel under the centrifuge lid and no cooling channel or the like is provided. The air circulates therefore only within the centrifuge bowl. Cooling is now achieved by a second medium, which is passed on the outside of the boiler. This can either be ambient air, which is conducted past the outside of the boiler, as is realized, for example, in the case of the centrifuge 5424 from Eppendorf AG. Alternatively, a special coolant is routed past the boiler via conduits spiraling against the boiler, ie the side walls and the bottom plate of the boiler, to remove heat. In the latter variant of the indirect cooling and cooling of the material to a temperature below the temperature of the ambient air is possible. An advantage of indirect cooling is the better controllability of the temperature to be set compared to direct cooling.

However, the cooling effect achieved with the indirect cooling is not yet as efficient as in direct cooling, which is why the energy consumption is correspondingly high with the same cooling capacity. This is a consequence of the areal limited contact of the cooling medium, which is led past the outside of the boiler.

Efforts are already known from the prior art to improve the indirect cooling. That's how it describes US 5,477,704 A a centrifuge vessel, on the outer side walls and the bottom plate of which cooling coils of copper are glued by means of an aluminum-filled epoxy resin. The aluminum-filled epoxy resin has a high thermal conductivity and helps to dissipate heat from the centrifuge bowl. The in the US 5,477,704 A disclosed cooling coils, which are glued to the boiler, are characterized by their special design: the voltage applied to the boiler side wall and the bottom plate side of the cooling coil is flattened, so as to increase the contact area between the cooling coil and boiler. However, an epoxy resin is difficult to apply to copper pipes and it takes a certain curing time before such a boiler can be used or further processed. In addition, the boiler and the composite epoxy resin / copper have different thermal expansion coefficients. The result of this is that, in the event of a change in temperature, clicks can occur which leave the user with an uncertainty with regard to the operational safety of the centrifuge.

The EP 0 224 238 A discloses a laboratory centrifuge according to the preamble of claim 1.

The JP 2000 015142 A discloses a laboratory centrifuge having a container having two thermally conductive contacting container layers having different thermal conductivity, wherein the higher thermal conductivity layer is disposed on the container exterior to be cooled by the cooling means.

The object of the present invention is to provide a laboratory centrifuge that allows efficient indirect cooling and is simple and inexpensive to produce.
Container in the context of the present invention are all devices in which a good to be cooled can be arranged directly or indirectly via a separate enclosure and which can be cooled by means of indirect cooling via a standing in heat conductive contact cooling device. The container according to the invention may be designed differently with respect to the outer shape. It can be round or kettle-shaped. In such a case, the container has a round bottom plate from which pulls up a side wall at the outer edge. The top of the container is closed by an openable lid. In an alternative embodiment, the container is angular, ie designed rectangular or square. He then has a rectangular or square base plate, extending from the outer edge of each four sidewalls. The top of the container is closed with a top plate. Depending on the use of the container either at least one of the side walls is designed as an openable door or the top of the container, ie the upper plate is formed as an openable lid. Whenever "sidewall" is mentioned, this term also includes the plural, ie "sidewalls".

Brief description of the invention

Surprisingly, it has been found that this object is achieved by a laboratory centrifuge with an at least two-layer container according to claim 1. This is surprising because so far there was no evidence that an at least two-layer centrifuge vessel can provide such a tremendous improvement in indirect cooling in a centrifuge.

The invention thus relates to a laboratory centrifuge according to claim 1. "Heat conductive contact" in the context of the present invention means that the contact must be such that the heat transfer can be carried out by heat conduction. So there must be a material contact, but this does not mean that this contact must exist directly - so between the two layers can also be arranged one or more intermediate layers. In the context of the present invention, "heat-transferring contact" means, for example, that the contact must be such that heat transfer can take place at least by one of the three principal heat transfer mechanisms, heat conduction, radiation or convection. It does not necessarily have to be a material contact. "Direct contact" between two objects in the context of the present invention means that two objects at least partially abut each other directly and thus touch each other. If, in the context of the present invention, the term "contact" or "contact point" is generally used, ie without the preceding words "heat-conducting" or "heat-transferring", this always means direct contact.
Advantageous developments are specified in the dependent claims.

Brief description of the figures

Fig. 1

eine schematische, ausschnittsweise Darstellung eines herkömmlichen Zentrifugenkessel in Kontakt mit einer Kühlleitung und

Fig. 2

eine schematische, ausschnittsweise Darstellung eines erfindungsgemäßen Zentrifugenkessel in Kontakt mit einer Kühlleitung.

The invention is illustrated by the following figures, which are additionally explained in detail in the detailed description of the invention. Show

Fig. 1

a schematic, partial view of a conventional centrifuge vessel in contact with a cooling line and

Fig. 2

a schematic, partial view of a centrifuge vessel according to the invention in contact with a cooling line.

Detailed description of the invention

The laboratory centrifuge according to the invention comprises a container, wherein the container is not integrally connected to a cooling device of the laboratory centrifuge and has a container body which has at least two in heat-conductive contact container layers with different thermal conductivity. The two container layers create a large contact area that improves heat transfer during cooling. Because the layer with higher thermal conductivity is arranged on the outside of the container to be cooled, wherein the layer with higher thermal conductivity has a thickness of less than 1 mm, the heat flow is in the direction of only in regions in heat conductive contact with the container surface to be cooled Cooling device increased. This results in an overall increased cooling efficiency.

In order to enable particularly efficient cooling, the thermal conductivities should differ by a factor greater than 10, preferably greater than 20, in particular greater than 100.

In a particularly preferred embodiment, the layer with lower thermal conductivity is formed from a material comprising stainless steel, steel, ceramic, glass and / or plastic and the layer with higher thermal conductivity is made of a material aluminum, gold, carbon, including its modifications graphite, diamond, diamond-like carbon and carbon nanotubes, copper, magnesium, brass, silver and / or silicon or their alloys formed. Then a particularly efficient heat transfer can be ensured and the boiler is also easy to produce. In particular, is also a Embodiment of the layer with higher thermal conductivity as a film advantageous, for example as a pyrolytic graphite foil (PGS), since this manufacturing technology is easily applied to the layer with lower thermal conductivity. As a layer with lower thermal conductivity, alternatively, so-called nanolayers can be used, that is to say a layer which was produced using nanotechnology. In the following, such a layer is understood to consist of a "nanomaterial".

The production costs can be reduced with good efficiency in that the layer with higher thermal conductivity has a small thickness of less than 0.5 mm and in particular less than 0.2 mm. It should be noted that, depending on the layer material, the heat flow decreases if the layers are too thick and the heat transport may be disturbed if the layers are too thin, so that there is an optimum with respect to the minimum thickness for each layer material, which the skilled person will experience on the basis of experiments and calculations will find out.

Advantageously, the container is surrounded by a tubular conduit, which is preferably wound helically around the container. The term "tubular" includes round tubes as well as tubes with at least one flattened side, in particular also rectangular tubes.

"Only in some areas" in the context of the present invention means that the contact area between the cooling device and the cooled outer surface of the container is smaller than the cooled outer surface of the container. The cooling device can also be formed by a plurality of separately operating devices, but their total contact area should be smaller than the cooled container outer surface.

Due to the efficiency of the indirect cooling enabled, it is possible to dispense with the provision of cooling lines at the bottom of the container. However, it is increasing For example, the temperature exponentially increases in a centrifuge vessel as a function of the rotational speed, so that additional cooling lines can be provided on the bottom of the vessel for very high rotational speeds and / or desired very deep cooling.

Of course, the indirect heat transfer according to the invention can also be coupled with a direct heat transfer, for example, the known rotor air assisted centrifugal cooling.

In summary, it can be stated that the inventors have recognized that in indirect cooling, the effectiveness depends substantially on the heat transfer between the elements of the heat exchanger, as will be explained below. In this case, only the heat conduction is taken into account for the description of the processes during the heat transfer and the heat radiation and convection are disregarded.

wobei Q̇ der Wärmestrom durch den Festkörper, λ die Wärmeleitfähigkeit, die eine Materialkonstante ist, A die Größe der Querschnittsfläche des Festkörpers, s die Dicke des Festkörpers und ΔT die Temperaturdifferenz zwischen der Eingangs- und Ausgangsseite des Wärmestroms sind.The heat flow within a solid is defined as: $$\dot{Q}=\lambda •\frac{A}{s}•\mathrm{\Delta }T.$$

where Q̇ is the heat flow through the solid, λ the thermal conductivity, which is a material constant , A is the size of the solid's cross-sectional area, s is the thickness of the solid, and Δ T is the temperature difference between the input and output sides of the heat flow.

The principle of the invention with its advantages will be explained in more detail below with reference to the drawing using the example of centrifuge boilers.

Based on Fig. 1 This principle is purely schematic for a known and partially shown in the prior art centrifuge vessel with a Boiler wall 1, which is in contact with a cooling line 2 explained. The illustrated by the arrows heat flow from the boiler inside 3 flows at a temperature T ₁ through the boiler wall 1, which has a wall thickness s ₁ , via the contact surface A between the boiler wall 1 and the cooling pipe 2 with a temperature T _A through the cooling medium leading material Cooling line 2, which has a wall thickness s ₂ , wherein the cooling medium has the temperature T ₂ .

und für den Wärmestrom durch das Kühlmedium führende Material der Kühlleitung 2: $${\dot{Q}}_2={\lambda }_2•\left(T_A-T_2\right)$$

For simplicity, the assumptions are further made that the wall thicknesses s ₁ and s _{2 are the} same, that is s = 1 mm, the cross-section of the contact surface A = 1 mm ² and the heat flow outside the contact surface A is zero, there so a Air gap is present. Thus, the heat flow through the boiler wall 1 can be made only by the contact surface A and for the heat flow through the boiler wall 1 then results: $${\dot{Q}}_1={\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1•\left(T_1-T_A\right)$$

and for the heat flow through the cooling medium leading material of the cooling line 2: $${\dot{Q}}_2={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2•\left(T_A-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\right)$$

After the continuity principle is $${\dot{Q}}_1={\dot{Q}}_2,$$

After inserting results: $${\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1•\left(T_1-T_A\right)={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2•\left(T_A-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\right),$$

With T ₁ - T _A = Δ T ₁ and T _A - T ₂ = Δ T ₂ finally follows: $${\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1•\mathrm{<figure-callout\; id="1"\; label="\Delta \; T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{T}_{}{}_1={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2•\mathrm{<figure-callout\; id="2"\; label="\Delta \; T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{T}_{}{}_2,$$

Consequently, if λ ₁ < λ _{2 is} chosen, then Δ T ₁ > Δ T ₂ .

In the application of a centrifuge T _{2 is} kept constant low by means of coolant. Conversely, this means that the temperature inside the boiler T _{1 will have} a much higher temperature difference from the temperature of the contact point T _A.

In order to be able to further lower the temperature in the interior of the boiler T ₁ , the possibilities are also available to reduce the wall thickness s ₁ and s ₂ and / or the boiler wall 1 made of a material with a very high thermal conductivity λ ₁ (eg Copper or silver), but the first possibility is technically limited by the functional design of the components and is usually exhausted and the second option is usually not possible for application reasons and the intended application, since, for example, copper or silver is not chemically are inert.

This leaves the practicable possibility to increase the contact area A. For this purpose, rectangular tubes can be used instead of round tubes, because usually round copper tube is used for the coolant-carrying components and the use of rectangular tube is a significant increase in the contact surface A. However, it is currently technologically impossible, a complete Contact the square pipe wall with the centrifuge boiler. There are always gaps where effectively no heat transfer takes place.

Mit dem Einsetzten der Formel für den Wärmestrom ergibt sich: $${\lambda }_1•B•\left(T_1-T_B\right)={\lambda }_{A-B}•A•\left(T_B-T_A\right)={\lambda }_2•A•\left(T_A-T_2\right).$$

Unter der weiteren Vereinfachung, dass die Materialien der äußeren Kesselschicht 11 und der Kühlleitung 12 dieselben sind und daher λ _A-B = λ ₂ gilt, vereinfacht sich der Zusammenhang zu: $${\lambda }_1•B•\left(T_1-T_B\right)={\lambda }_2•\frac{A}{2}•\left(T_B-T_2\right),$$

und mit T ₁ - T_B = ΔT ₁ und T_B - T ₂ = ΔT ₂ zu: $${\lambda }_1•B•\mathrm{\Delta }{T}_1={\lambda }_2•\frac{A}{2}•\mathrm{\Delta }{T}_2.$$

As a solution according to the invention, an additional heat conducting layer is provided on the outer wall of the boiler by the inventors, as in Fig. 2 again purely schematically for the resulting and illustrated by the arrows heat flow is shown in sections. As a result, an additional contact point with a large contact surface is inserted.
Unlike the centrifuge kettle after Fig. 1 So here is in addition to the interior of the boiler bounding inner boiler layer 10 with the thickness s _{10 applied} an additional outer shell layer 11 with the thickness s ₁₁ of good heat conducting material as boiler outer wall. The cooling line 12 has the thickness s ₁₂ .
For simplification, the assumptions of Fig. 1 in that the wall thicknesses are all equal to s = 1 mm, the cross section of the contact surface A arranged between the outer boiler layer 11 and the cooling line 12 is 1 mm ² and the heat flow outside the contact surface A is equal to zero, that is to say where there is an air gap.
In addition, however, here there is a contact surface B between the boiler layers 10, 11, which is much larger than the other contact surface A. The heat flow is now through the three materials of the inner shell layer 10, the outer shell layer 11 and the cooling line 12 and through the two intermediate contact points A, B, which differ significantly from their size.
According to the continuity principle, here too: $${\dot{Q}}_1={\dot{Q}}_{B-A}={\dot{Q}}_2,$$

Using the formula for the heat flow yields: $${\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1•B•\left(T_1-T_B\right)={\lambda }_{A-B}•A•\left(T_B-T_A\right)={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2•A•\left(T_A-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\right),$$

Further simplifying that the materials of the outer shell 11 and the cooling duct 12 are the same, and therefore λ _{A - B} = λ ₂ , the relationship simplifies: $${\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1•B•\left(T_1-T_B\right)={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2•\frac{A}{2}•\left(T_B-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\right).$$

and with T ₁ - T _B = Δ T ₁ and T _B - T ₂ = Δ T ₂ to: $${\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1•B•\mathrm{<figure-callout\; id="1"\; label="\Delta \; T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{T}_{}{}_1={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2•\frac{A}{2}•\mathrm{<figure-callout\; id="2"\; label="\Delta \; T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{T}_{}{}_2,$$

That is to say, if λ ₁ < λ _{2 is} selected, Δ T ₁ > Δ T ₂ must therefore again be Δ. However, here a part of the required temperature difference is intercepted by the much larger contact surface B. Or put differently $$B•\mathrm{<figure-callout\; id="1"\; label="\Delta \; T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{T}_{}{}_1>\frac{\mathrm{<figure-callout\; id="2"\; label="A"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">A</figure-callout>}}{2}•\mathrm{<figure-callout\; id="2"\; label="\Delta \; T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{T}_{}{}_2,$$

In the application of a centrifuge with cooling T _{2 is} kept constant low by means of coolant. However, this implies in reverse that the temperature inside the boiler T _{1 must} have a higher temperature difference to the temperature of the contact point T _B , but this is in turn lower than in connection with Fig.1 described since B >> A.

Although the principle according to the invention has been described herein with reference to two container layers with different thermal conductivity, it is clear that three or more layers can also be used. These may in particular be anti-corrosion, anti-contamination or the like layers. It is only important that the layer with higher thermal conductivity is arranged on the container outer surface to be cooled. However, both the higher and the lower thermal conductivity layer as well as the lower thermal conductivity layer may have one or more several additional layers may be arranged to adapt the container to particular conditions of use.

example

Hereinafter, the effects of the invention will be described with reference to a preferred embodiment compared with a comparative example known from the prior art.

A laboratory centrifuge 5415R from Eppendorf AG was used, which has as cooling line 2, 12 a spiral rectangular tube with a width of 9.5 mm, a height of 5.5 mm and a material thickness of 0.5 mm. For this purpose, a serial centrifuge vessel 1 with a diameter of 185 mm, a height of 70 mm and a wall thickness of 1 mm (article No. 5426 123.101-00) from Eppendorf AG was used, which was made of V2A stainless steel (thermal conductivity about 15 W / m * K) and with thermal grease (thermal conductivity about 15 W / m * K) provided in the cooling line 2 was arranged to form the comparative example. For the exemplary embodiment according to the invention, the standard stainless steel centrifuge vessel 10 (article No. 5426 123.101-00) from Eppendorf AG was provided with a 0.1 mm thick copper coating 11 (thermal conductivity about 350 W / m.sup.K), otherwise it was the experimental setup is the same, ie The centrifuge vessel was connected to the rectangular cooling line 12 by means of thermal paste (thermal conductivity also about 15 W / m * K).

In both cases, the centrifuge 5415R was operated with a conventional rotor F45-24-11 from Eppendorf AG for one hour at a maximum of 13200 rpm. The minimum achievable sample temperature was measured with the temperature meter. The results are recorded in the table. <U> Table </ u> 5415R with centrifuge bowl without Cu coating 5415R with centrifuge bowl with Cu coating Room temperature [° C] 25 26 Sample temperature [° C] 3.9 0.4

The results show that a significantly lower sample temperature is achieved by the copper coating 11 of the centrifuge vessel 10 with the same cooling capacity. By the copper coating 11, the thermal conductivity of the centrifuge tank 10 and thus the efficiency of the cooling system is improved. It is achieved with the same electrical energy consumption, a lower sample temperature.

Thus, it has been demonstrated that the present invention allows much more efficient indirect cooling from the exterior of the container to the interior of the container. The improvement of the heat conduction and the heat transfer of centrifuge boilers results in cooled centrifuges a reduction of the necessary performance of the refrigeration system. Due to the higher efficiency of the centrifuge, a higher rotational speed can be run for the same centrifuging product temperatures and / or the absorbed power of the cooling unit can be reduced with the same centrifuging product temperature and the same rotational speed.

The principle according to the invention is based on the finding that with indirect cooling of a container surface which is larger than the contact surface between the container and the cooling device, the cooling effect can be increased if the container has a layer with higher thermal conductivity in addition to the layer with low thermal conductivity and the layer with higher thermal conductivity is arranged on the container outer surface to be cooled and is in conductive contact with the cooling device. Thus, the cooling capacity is better transferred to the interior of the container to be cooled there Good.

An alternative solution is to make the contact area between the cooling device and the cooled surface of the container at least equal to the cooled container surface. This can be realized by virtue of the fact that the cooling device is part of the layer of the container with greater thermal conductivity.

For this purpose, it can be provided, for example, that the second layer consists of a solid, such as copper or the like, and the cooling device is arranged directly in this layer.

On the other hand, the cooling device can also be arranged in a liquid, gel or the like which is in heat-conducting contact with the layer of lower thermal conductivity and which itself has a higher thermal conductivity. For this purpose, either the container has a layer which has, between itself and the layer with lower thermal conductivity, a cavity which can be filled with a liquid, gel or the like, in which the cooling device is arranged (the thermal conductivity of this further layer is insignificant, as it relates to FIG the cooling device is outside). Or the container does not itself comprise the liquid, gel or the like, but it is provided with the cooling means housed therein in a device in which the container can be arranged to heat the liquid, gel or the like with the layer of low heat conductivity is in managerial contact. For this purpose, for example, the container in the sense of a bath itself, preferably to the edge completely, are immersed in the liquid, gel or the like or the liquid, gel or the like is in contact only with a part of the container outer surface. For transport, care should preferably be taken to ensure adequate sealing of the liquid, gel or the like.

Between the liquid, gel or the like and the layer with low thermal conductivity may also be arranged a further layer with higher thermal conductivity. For example, the liquid, gel or the like with the Cooling device may be disposed within a copper cladding, which is either integrated directly into the container or provided in the device, where then the container with this copper cladding is brought into direct contact. This can also achieve the seal. The terms "liquids" or "gels" include both Newtonian liquids and non-Newtonian liquids, sols, dispersions, suspensions, as well as any combination of two or more of these listed substances. In particular, a liquid or gel can be selected from the following group: water, ionic liquids, suspensions of carbon nanotubes, cooling brines, eutectics or eutectic mixtures and similar materials. Antifrogen N, Antifrogen L and Antifrogen SOL) or potassium formate (Antifrogen KF) Furthermore, find ionic liquids, such as 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium chloride , 1-Butyl-3-methylimidazolium methanesulfonate, 1-ethyl-2,3-dimethylimidazolium ethylsulfate (marketed under the brand Basionics® BASF SE, 67063 Ludwigshafen, DE) can also be used polyalkylene glycol derivatives.

The advantage of this alternative solution is that the cooling device no longer has to be in direct contact with the container surface to be cooled, possibly mediated by the intermediary of a thermal compound. As a result, there are no such great demands on the accuracy of, for example, the winding geometry of a cooling tube with respect to the container outer contour, which reduces costs.

Claims (7)

1. A laboratory centrifuge with a container, said container being non-integrally connected to a cooling device of the laboratory centrifuge and comprising a container body, characterised in that the container body comprises at least two container layers (10, 11) with different heat conductivities which are in heat-conducting contact, wherein the layer with higher heat conductivity (11) is disposed on the outside of the container body to be cooled by the cooling device, wherein the layer with higher heat conductivity (11) has a thickness of less than 1 mm.
2. The laboratory centrifuge according to claim 1, characterised in that the heat conductivities differ from one another by a factor greater than 10, preferably greater than 20 and in particular greater than 100.
3. The laboratory centrifuge according to one of the preceding claims, characterised in that the layer with lower heat conductivity (10) is made of a material comprising stainless steel, steel, ceramic, glass, nano material and/or plastic and the layer with higher heat conductivity (11) is made of a material comprising aluminium, gold, carbon, copper, magnesium, brass, silver and/or silicon or alloys thereof.
4. The laboratory centrifuge according to one of the preceding claims, characterised in that the layer with higher heat conductivity (11) has a thickness of less than 0.5 mm and in particular less than 0.2 mm.
5. The laboratory centrifuge according to one of the preceding claims, characterised in that the container is surrounded on its sidewall and/or its base by a tubular cooling conduit (12) carrying a cooling medium, which cooling conduit is preferably wound in a spiral around the side wall and/or on the base.
6. The laboratory centrifuge according to one of the preceding claims, characterised in that the heat-conducting contact between the container and the cooling device is made via a heat-conducting paste.
7. The laboratory centrifuge according to one of claims 1 to 5, characterised in that the heat-conducting contact between the container and the cooling device is made via a liquid or gel.

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