EP1574260A1 - Laboratory centrifuge with swinging buckets - Google Patents

Abstract

The rotor of a laboratory centrifuge, rotating in air without an air chamber, has rotor arms (2) ending in fork arms (4) between which containers (6) are hung to swing out on axes (5). On each rotor arm and/or on each container an aerodynamically formed fairing (12,16,20) in the direction of travel is installed in front of at least the radially outer lying areas of the regions (7) of the containers which in the swung out position face the inflow. The fairings are fastened on the rotor arms.

Description

The invention relates to the rotor of a laboratory centrifuge with the features of Preamble of claim 1.

Generic rotors are from the catalog of the applicant
Products and Applications for the Laboratory 2003
Pages 101 - 107
known. This construction method is standard today with all centrifuge manufacturers.

The generic construction offers the advantage of the swingable container, where the direction of force remains constant at all speeds. Because the Can be hung out of containers, they can be removed from the rotor and convenient Be loaded and unloaded outside the centrifuge. Like the aforementioned prospectus pages show, the containers are available in different designs, To be able to take sample containers of different kinds, this is enough of large bottles over sample tubes all the way through into a box-shaped open Containers of microtiter plates (page 107, center right).

To generate very high, the centrifuging shortening forces run generic Centrifuges with very high speeds. The rotor with the containers is exposed to very high air flow rates.

As the above brochure pages show, the containers are mainly in Direction of their attachability between the fork arms, towards good Loading capacity and with a flat footprint for safe installation Loading and unloading trained. The containers are therefore hardly under aerodynamic Optimize aspects.

At high airflow velocities, this results in strong turbulence on the rotor and the containers. This results in the significant speeds the rotor a high air resistance, which leads to a strong air heating leads. The high air resistance must with a strong, also a lot of heat be compensated generating engine. This results in a high air heating in the provided for safety reasons, the entire centrifuge surrounding housing. This heating would cause the samples to be centrifuged affect and must be compensated with a cooling device. By These measures also significantly increase the cost of a laboratory centrifuge. Furthermore, caused by the air turbulence very strong noise caused by the surrounding housing can only be insufficiently damped.

To solve these problems, air chambers are known, as described in DE 4027993 A1 shows. The Windkessel is a streamlined smoothly shaped inner housing, the revolving surrounding the rotor. Inside the air chamber, the air is running with the engine, so that there is no turbulence at this. Disadvantageous on Windkessel is but the enclosure of the rotor and the container, so that a Temperature control of the samples is difficult to desired temperatures. The costs of such constructions are also very high.

The US 2003/0199382 A1 also shows a centrifuge with a wind tank, the However, it is very flat and the oscillating stored containers only in ausgewungenem Condition absorbs. DE 38 03 255 C1 also shows a Windkesselkonstruktion, in which, however, the containers are not removable removed are loaded through a cutout in the lid of the air chamber can.

US 2002/0173415 A1 shows a generic rotor whose rotor arms have a well-aerodynamically shaped outer surface lying on circular circumference, between which, however, the swung out containers with their radial far outward areas and thus cause strong air disturbances.

DE 24 47 136 A1 shows an ultracentrifuge, so an extremely high-revving Centrifuge whose rotor basically runs in a vacuum, resulting in aerodynamic Unnecessary considerations.

DE 101 55 955 C2 shows a generic rotor in which the aerodynamic Problem is solved in a completely different way, namely by means of the Containers arranged turbulence generators, which generated the wake turbulence to influence.

Finally, DE 25 26 534 A1 aerodynamic fairing parts Heavy goods vehicles.

The object of the present invention is to provide a generic To create a rotor, without windbox at high speeds with less Engine power produces little heat and noise.

This object is achieved with the features of claim 1.

According to the invention, each rotor arm and / or each container has an aerodynamic design Cover provided at least on the radially outer Range of tanks to improve the aerodynamics. Energetic effects of Air flow, such as heat and noise generation, grow at the 4th power the radial distance from the rotor axis. In the swung out state, so at high speeds, the containers tower over the rotor arms and form the radial outermost areas where the highest air speeds available. Because of the increasing with the 4th power of the radius disturbing Effects is most important here an aerodynamic fairing. The aerodynamic panels reduce the air turbulence in these places very strong. The air resistance is greatly reduced, so that a significant lower engine power sufficient to drive. The resulting from air turbulence Heat is also greatly reduced, as is noise production. A wind boiler is not required, so that the samples in the containers through Heating and cooling devices in the housing of the centrifuge in the desired manner can be tempered. The containers themselves can be in theirs from others For reasons required, aerodynamically unfavorable shape remain, so that their utility value is not restricted. The panels can be considered relative simple and inexpensive attachments may be provided, e.g. also known generic rotors can be retrofitted.

Advantageously, according to claim 2, the panels on the rotor arms, e.g. attached to the fork arms in the immediate vicinity of the container. You can here securely fastened to the high aerodynamic forces and impacting To be able to absorb centrifugal forces.

The panels may be fixedly secured to the rotor arms, wherein they be aligned so that they are standing in swing position container cover. Advantageously, however, they can also be swung out according to claim 3 be stored to auszuschwingen with the containers. This is also at low Speeds already achieved a good aerodynamic disguise of the containers. Above all, results from the swing-out panels that at standing centrifuge with the containers hanging, a freer access from the top to the containers so that they are comfortable and without interference from the panels are removable.

According to claim 4, it is also advantageous, the cladding directly to be attached to the containers. However, the panels must then be removable be to allow the lifting out of the container between the fork arms.

The panels may be formed, for example, as a lightweight solid body, for example made of high-strength foam material, but are advantageously formed according to claim 5 as a shell body. They can be made very stiff and light in order to reduce the centrifugal forces that increase with the mass of the panels.
An aerodynamic fairing according to claim 1 in the direction of travel in front of the containers gives the greatest effect. However, an additional rear panel of the container according to claim 6, so a full panel, the air turbulence can further advantageously reduce.

As an advantageous alternative to individual panels in front of and behind the containers the features of claim 7 are provided. Here are the peripheral areas between the containers with circular sector-shaped panels closed, so that except for small gaps on the circumference of the rotor an annular smooth closed construction with optimal aerodynamics results.

Advantageously, the features of claim 8 are provided. This results in the critical radially outer regions of the container a full panel with optimal aerodynamic improvement.

Advantageously, the features of claim 9 are provided. This results a construction that can be easily fastened to the container, which at the same time is the one anyway required to close the container lid.

Figur 1

eine Draufsicht auf einen Rotor mit Behältern unter Darstellung dreier unterschiedlicher Ausführungsformen von Verkleidungen,

Figur 2

einen Schnitt nach Linie 2 - 2 in Figur 1,

Figur 3

einen Schnitt nach Linie 3 - 3 in Figur 1,

Figur 4

einen Ausschnitt aus Figur 1 mit einem auf alternative Weise verkleideten Behälter,

Figur 5

einen Schnitt nach Linie 5 - 5 in Figur 4 und

Figur 6

in Ansicht gemäß Figur 4 eine Variante zu dieser Ausführungsform mit Deckel.

In the drawings, the invention is shown for example and schematically. Show it:

FIG. 1

a top view of a rotor with containers showing three different embodiments of panels,

FIG. 2

a section along line 2 - 2 in Figure 1,

FIG. 3

a section along line 3 - 3 in Figure 1,

FIG. 4

1 shows a detail of FIG. 1 with a container clad in an alternative manner, FIG.

FIG. 5

a section along line 5-5 in Figure 4 and

FIG. 6

in a view according to Figure 4, a variant of this embodiment with a lid.

FIG. 1 shows a plan view of the rotor 1 of a laboratory centrifuge. He points in the embodiment, four rotor arms 2 and is mounted on a shaft 3, The vertical standing of an engine, not shown in the with an arrow driven direction of rotation is driven. The overall construction is from a housing, not shown, essentially serving backup reasons closed, which has an upper lid, through which the rotor, so as shown in Figure 1, accessible from above. For details of these known Design is on the aforementioned prospectus pages directed.

The rotor arms 2 go radially outward in forks with fork arms 4, which having inwardly projecting trunnions 5, at which between the fork arms 4 containers 6 are mounted.

As FIG. 2 shows, the containers 6 illustrated in the exemplary embodiment have a substantially square cross-section and each have their in Direction of travel from the lying end face and the rear end face. 8 Longitudinal grooves 9, which open to the flat bottom surface 10 of the container 6 and rounded at its upper end below the upper end of the container 6 rounded are. At standstill of the rotor 1, the container 6 hang with the upper closed end of the grooves 9 on the pivot pin 5 and can go up be lifted out between the fork arms 4, wherein the pivot pin 5 itself move to the lower end through the grooves 9. Conversely, the containers be hooked again and then hang pendulum with focus below the pivot 5 at this.

Figure 1 shows the swung-out state of the container 6 at higher speeds. The container 6 are horizontal. The full swing-out state is already achieved at relatively low speeds.

As FIGS. 1 and 2 show, the containers 6 are extremely unfavorable aerodynamically shaped. They are at the indicated in Figure 1 with an arrow direction of rotation clockwise the air flow with the flow to the vertical standing front end face 7 and thus have a very high Drag coefficient. The sharp corners and the groove 9 provide strong Air turbulence. On the other hand, the illustrated square cross section very favorable for the formation of many holes 11, in the schematic embodiment are provided for receiving test containers.

In another embodiment, the containers 6 may also have a large interior space be designed to accommodate a single large bottle or as largely open construction, which essentially only wall areas in the area the bottom surface 10 and the end faces 7 and 8 and for receiving a Stack of microtiter plates is provided.

For the aerodynamic improvement of the illustrated rotor 1 are according to the invention Coverings provided hereinafter with reference to several embodiments to be discribed.

In Figures 1 and 2, a panel 12 is shown, which, as in Figure 2 with shown in solid lines, as a curved shell with an outer half cylinder shape is trained. It is e.g. with fastening means 13 on a fork arm 4 sure attached and covers, as Figure 4 shows, which directed the air flow front end face 7 of the container 6 from. As Figure 2 shows, this is a achieved aerodynamically extremely favorable cover of the container in the direction of travel, which causes a very strong reduction in air turbulence at this Container yields.

As shown in dashed lines in Figures 1 and 2, the radially outer Area of the panel 12 at 14 rounded rounded and dome-shaped closed to the edge 15 (Figure 2) run. This will be in the radially outer Area of the panel 12, the aerodynamic adaptation to the container. 6 further improved.

It should be noted that the air inflow effects at a given rotor speed with the 4th power of the radius, ie the distance from the axis of Wave 3 rise. Aerodynamic measures are therefore in the radially outer Areas of the container 6, in the vicinity of the bottom surfaces 10 am most important.

The described panel 12 can be seen on all four rotor arms 2 in the illustrated Be provided manner.

In an alternative variant, also shown in FIG. 1, a lining is provided 16 provided in the radially inner end portion substantially the shape of the panel 12 corresponds, as shown in Figure 2 is. In the outer end region in the vicinity of the bottom 10 of the container 6 is the panel 16 also formed rounded, as on the panel 12th shown at 14. However, it is, as Figure 1 shows, to the lower corners of the container 4 formed to extend over the bottom 10 and thus gives a even better aerodynamic fairing.

The panel 16 is located at its radially inner ends 17 further outward than that radially inner end of the panel 12. It is essentially only there, where maximum aerodynamic effect is needed, namely at the radial outer area of the container 6.

In contrast to the fork arm 4 attached to the panel 12 is the panel 16 with supports 18 directly attached to the container 6 on the front end face 7. The attachment to the supports 18 is designed removable. The supports 18 can e.g. be plugged into holes on the end face 7 of the container 6. The Removability of the panel 16 is required because the panel 16 at Standstill of the rotor 1, ie with hanging container 6, below the fork arms 4 hangs and thus hinder the extraction of the container upwards.

In Figure 1, the panel 16 is still another mounting option indicated. Instead of attachment to the container 6, the panel could be 16 be pivotally mounted with an arm 19 about the pivot pin 5. She would then pivot with the container 6, without hindering this when removing. A corresponding pivotal attachment to the fork arm 4 could also be provided for the panel 12.

FIG. 1 also shows a third embodiment of a lining in the form of a Sector cover 20 is provided, which, as Figure 3 shows, also as a shell is formed, which closed up, down, and radially outside is trained. The sector cover 20 is on the leading fork arm. 4 a rotor arm 2 and the trailing fork arm 4 of the next rotor arm 2 fixed with fasteners 21 and aerodynamically disguises the sector between a container 6 and the next container 6. With four at one Rotor provided sector panels 20 and between the sector panels arranged containers 6 results, except for column, an aerodynamic perfect full fairing.

As Figure 2 shows, is a panel 12 in the direction of travel before the flow opposite front Stimfiäche 7 of the container 6 is arranged. Symmetrically, an e.g. identical trained panel also before the rear end face 8 be arranged to each container 6 its own aerodynamic To give full fairing.

Figures 4 and 5 show a variant in which in the illustrated Swinging standing container 6 with its radially outer Regions, beyond the ends of the fork arms 4, of a shape a tub 25 formed panels is surrounded. The tub 25 is with Arms 26 mounted on an aligned in alignment with the pin 5 axis 27, can but also, similar to the panel 16, directly on the pin. 5 be stored. Thus, the tub 25 is disposed with the container 6 swing out.

In an alternative, which is indicated by dashed lines in Figure 4, the trough 25 may with arms 28, e.g. hook-shaped overlap the upper edge of the container 6, must be attached directly to this, but must then before removing the container from the centrifuge are released from this.

The tub 25, as is apparent from Figures 4 and 5, aerodynamically extreme be designed advantageously and the critical radially outer areas of the container 6 dress with high aerodynamic efficiency.

The panels 12, 16, 20 and 25 shown are in the figures as shell body shown. They have to absorb very high forces without deformation can. They are therefore very stable materials, e.g. Metals or extremely strong, e.g. fiber-reinforced plastics, advantageous for their production. Possibly the shells can be reinforced by stiffening ribs, advantageous on their inside. Even foams with rigid foam can be used for stiffening be provided.

FIG. 6 shows a further embodiment similar to that in FIGS. 4 and 5 is. It has already been mentioned in Figure 4, that the trough 25 with dashed lines shown arms 28 may be attached to the upper edge of the container 6. A Similar solution is shown in FIG.

The trough 25 can essentially correspond to that according to FIGS. 4 and 5. she is on one side, namely on the visible in Figure 6 side of the container. 6 with a tab 30 connected to a lid 31 from the top of the opening the container 6 plugged and there, for. via the dashed line, is secured in the container inserted inner part 32. The tab 30 must be very be formed tensile strength, but at the same time flexible elastic to the removal of the Cover 31 to allow.

The container 6 may preferably with its lower dashed lines Contours in a corresponding receptacle formed in the solid material Tray 25 be received positively.

Before lifting out of the container 6 from the fork arms 4 must first Cover 31 lifted by bending the tab 30 from the container and the Page to be folded. Then the tub 25 can be withdrawn from the container 6 down become. Reattaching to a container before centrifuging happens in reverse order.

This results in a secure mounting of the tub 25 on the container 6 below simultaneous formation of a lid 31, which is required anyway on the container 6 is to in well-sealed training the samples to be centrifuged in the Container 6 to protect against air turbulence, which leads to a carryover of Samples to other samples and lead to contamination of the centrifuge could.

Claims (9)

Rotor (1) of a laboratory centrifuge running without air in the air, with rotor arms (2) ending in fork arms (4), between which containers (6) are swingably suspended on axles (5), characterized in that on each rotor arm (2, 4 ) and / or on each container (6) an aerodynamically shaped lining (12, 16, 20, 25) in the direction of travel in front of at least the radially outer regions of the flow-facing regions (7) of standing in swinging position container (6) is arranged. Rotor according to claim 1, characterized in that the panels (12, 16, 20, 25) are fixed to the rotor arms (2, 4). Rotor according to claim 2, characterized in that the fastenings (19, 26) are designed to be swingable. Rotor according to claim 1, characterized in that the claddings (16) are detachably attached to the areas of the containers (6) lying outside the fork arms (4) in the swing-out position. Rotor according to claim 1, characterized in that the coverings (12, 16, 20, 25) are designed as shell bodies. Rotor according to Claim 1, characterized in that additional panels are arranged in front of the areas (8) of the containers (6) facing away from the flow. Rotor according to claim 1, characterized in that claddings (20) are arranged in a sector of a circle between successive containers (6). Rotor according to claim 1, characterized in that the panels are formed as the swinging in radially outward areas of the container (6) embracing troughs (25) removably attached to the container (6) (28) or on the rotor arm (4) swinging out (26) are. Rotor according to claim 4, characterized in that the coverings (25) are each secured to a cover (31) that removably closes the container (6) via a tension connection (30).

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