EP0025945A1 - Bowl for centrifuge - Google Patents

Abstract

Centrifugal bucket 1, 31 consists of a plastic material 52, in which a U-shaped metal part 2, 32 is imbedded. Receiving grooves 3, 33 for sustaining the pegs of the centrifugal suspension gear are formed in metal part 2, 32, so that in the transmission of the centrifugal force from the bottom of the centrifugal bucket on receiving groove 3, 33 solely the metal part is acting as load transferring connection.

Description

The invention relates to a centrifuge cup for hanging on the spigot of the centrifugal head of a centrifuge, the wall of which in the region of the holder of the spigot on the centrifuge cup each have a receiving groove.

The previously known centrifuge beakers were made from a one-piece metal part, in which they were produced by milling, turning and corresponding machining from solid or from pre-pressed material. Naturally, this type of manufacture is extremely costly and labor-intensive and, moreover, is burdened with an extraordinarily high consumption of material. The previously known centrifuge cups were made from a compact or from solid material because the centrifugal forces occurring during centrifugation in centrifuges are so high that it has previously been assumed that centrifuge cups produced as one-piece parts could withstand such high loads.

The object of the present invention is to develop a centrifuge beaker of the type mentioned at the outset in such a way that the manufacturing costs and material costs are substantially reduced while maintaining the same strength and durability values.

To achieve the object, the invention is characterized in that the centrifuge cup consists of a plastic material and a metal part is embedded in the plastic material.

The present invention therefore takes a completely new path by overcoming the prejudice that centrifuge cups made from a one-piece metal part, from solid or from a compact can withstand the centrifugal forces that occur. In-depth tests have shown that the same good strength and durability values can be achieved by embedding a metal part in a plastic material, whereas the manufacturing and material costs are significantly reduced. However, when embedding the metal part in the plastic material, it is essential that the metal part is embedded in such a way that it largely absorbs the forces exerted on the centrifuge cup by the pins of the centrifuge hanger (which are absorbed by the receiving groove). It is preferred here if the metal part is designed as a U-profile, the legs of which are arranged parallel to the receiving groove and a holder is provided on the legs for receiving the pins of the centrifuge.

By designing the metal part as a simple U-profile, the advantage of low manufacturing costs is achieved because it has been shown that a closed beaker is not required, but that such a U-profile is sufficient, which extends from the peg of the centrifuge to the receiving groove of the centrifuge beaker fully absorbed and distributed forces exerted.

It is preferred here if the holder arranged on the legs is designed as a recess in the legs which runs parallel to the receiving groove and whose upper limit is provided with a radius which is adapted to the radius of the pins.

This means that the pins are inserted into the receiving groove on both sides of the centrifuge cup, the upper limit of the receiving groove (during the Spin process is the radially inward boundary of the receiving groove) is formed by the metal part, which has a radius at this point that is adapted to the radius of the pin.

At this point, the forces exerted by the pegs of the centrifuge hanger are transmitted to the legs of the metal part. After the metal part is a symmetrical U-profile, the forces are then transferred to the closed base leg of the U-profile.

In order to make it easier to hang the pegs and to insert them into the receiving groove on the side of the centrifuge cup, the lower part of the receiving groove (radially outward part) is widened so that the pegs can be inserted easily.

Only in its upper (radially inward lying part) is the width of the receiving groove adapted to the diameter of the pegs, so that they are encompassed by the radius of the metal part with little play.

In a further embodiment, the metal part is also designed as a U-profile, but there is no recess with a larger diameter going up from the base region, which opens into a recess with a smaller diameter, the width of the latter recess being slightly larger than the diameter of the pin to be hooked in Centrifuge suspension. In this second embodiment, the receiving groove is not designed as a recess, but as an impression in the two opposite legs of the U-profile. This results in an even better mechanical resilience of the metal part because recesses that weaken the cross section are avoided.

The metal part has bent legs, which, starting from the bottom area, take up a certain distance and rise in the area at the beginning of the opening have groove facing outwards, so that the two legs have a greater distance in the upper, free area than the bottom area. This creates the possibility of creating the receiving groove designed as an embossing from the material of the metal part, without having to make openings in the material of the legs. The design of the receiving groove as an embossment has the further advantage that the upper part of the receiving groove, which is heavily loaded by the pin of the centrifuge suspension, is particularly dimensionally stable because the material of the metal part is bent outwards horizontally in the region of the "roof" of the receiving groove and this results in an extremely resilient, force-transmitting connection from the journal of the centrifuge hanger to the metal part embedded in the plastic material.

It is also essential in the second-mentioned embodiment that the receiving groove itself is not lined or clad with plastic, so that in this mechanically highly stressed area only the material of the metal part rests on the pin of the centrifuge hanger, while the plastic material is embedded in the metal part and only that The spacing of the free legs of the metal part also serves as a filler.

Instead of forming the metal part from a U-profile with two free legs, it can also be provided in a further embodiment, not shown, to design this metal part as a continuous, self-contained pot.

In the preferred case of the second exemplary embodiment, however, with the metal part being designed as a U-shaped profile, there is still a substantial saving in material and weight given because the walls of the centrifuge cup adjoining the metal part are formed from the plastic material, so that overall (plastic material plus metal part) there is a self-contained centrifuge cup that is only open at the top.

In addition, the metal part of the second embodiment also has ribs (beads) in the bottom area and at least partially in the area of the side legs, which further improves the mechanical strength and dimensional stability.

Another essential feature of the present invention is that the centrifuge beaker, which is open at the top, can be closed by a tightly closing hood, a snap-in connection being provided between the hood and the top of the centrifuge beaker in a preferred embodiment. The use of a tightly closing hood at the end of the centrifuge cup achieves the advantage that aerosol formation and spraying of this aerosol in the vicinity of the centrifuge is prevented during the centrifuging process. This is particularly harmful when processing infectious material. Up to now, co-rotating wind boiler rotors had been used for this, which are extremely costly and very difficult to operate the centrifuge.

According to the present invention, one simply uses a tightly closing hood, so that the wind boiler rotor, which is expensive and expensive to use, can be dispensed with.

It is important that the metal part does not extend to the edge of the centrifuge cup, but that the plastic material is used in this edge area. Here by the entire centrifuge beaker with metal part can be produced in an injection molding process and the upper peripheral edge can be equipped with a projection in the injection molding process by appropriate shaping of the tool, which results in a snap connection with the hood.

Various materials can be selected as the material for the metal part. You can use a glass fiber reinforced plastic material or different metals such as stainless steel, sheet steel or a high-strength aluminum alloy. A metal insert made of a high-strength light metal has proven to be the cheapest choice of material, which also has the advantage that it is less expensive than other metals. As a result, the centrifugal force and thus the force to be transmitted to the metal part in the receiving groove is lower than if a heavier metal had been used.

Further features of the invention are the subject of the remaining subclaims.

The subject matter of the present invention results not only from the opposition of the individual claims, but also from the combination of the individual claims with one another.

In the following, the invention is explained in more detail with the aid of drawings showing only a few possible embodiments. Further features and advantages of the invention which are essential to the invention emerge from the drawings and their description.

• Fig. 1 Seitenansicht des Zentrifugenbechers mit dem eingelegten Metallteil,
• Fig. 2 Schnitt gemäss der Linie II-II in Fig. l,
• Fig. 3 Draufsicht in Richtung des Pfeiles III in Fig. 2,
• Fig. 4 Seitenansicht des Metallteils,
• Fig. 5 Seitenansicht in .Richtung des Pfeiles V in Fig. 4,
• Fig. 6 Draufsicht in Richtung des Pfeiles VI in Fig. 4,
• Fig. 7 Seitenansicht der Haube, mit der der Zentrifugenbecher verschlossen wird,
• Fig. 8 Sicht in Richtung des Pfeiles VIII nach Fig. 7 auf die Haube,
• Fig. 9 Unteransicht der Haube in Richtung des Pfeiles IX in Fig. 7,
• Fig. 10 Schnitt gemäss der Linie X-X im zweiten Ausführungsbeispiel eines Zentrifugenbechers nach Fig. 11,
• Fig. 11 Schnittansicht des Zentrifugenbechers in der zweiten Ausführungsform gemäss Schnitt XI-XI in Fig. 12,
• Fig. 12 Seitenansicht des Zentrifugenbechers nach Fig. 11 in Pfeilrichtung XII,
• Fig. 13 Draufsicht auf den Zentrifugenbecher nach Fig. 11 in Pfeilrichtung XIII,
• Fig. 14 Schnitt gemäss der Linie XIV-XIV in Fig. 12,
• Fig. 15 Seitenansicht des Metallteils,
• Fig. 16 um 90 Grad gedrehte Seitenansicht des Metallteils nach Fig. 15 in Richtung des Pfeiles XVI,
• Fig. 17 Draufsicht auf das Metallteil in Pfeilrichtung XVII in Fig. 15,
• Fig. 18 Seitenansicht der Haube im zweiten Ausführungsbeispiel,
• Fig. 19 um 90 Grad gedrehte Seitenansicht der Haube gemäss Pfeil XIX in Fig. 18,
• Fig. 20 Detaildarstellung der Lasche der Haube gemäss Fig. 19,
• Fig. 21 Unteransicht der Haube gemäss Pfeilrichtung XXI in Fig. 19.

Show it:

• 1 side view of the centrifuge cup with the inserted metal part,
• 2 section along the line II-II in Fig. 1,
• 3 top view in the direction of arrow III in Fig. 2,
• 4 side view of the metal part,
• 5 side view in the direction of arrow V in Fig. 4,
• 6 top view in the direction of arrow VI in Fig. 4,
• 7 side view of the hood with which the centrifuge cup is closed,
• 8 view in the direction of arrow VIII of FIG. 7 on the hood,
• 9 bottom view of the hood in the direction of arrow IX in FIG. 7,
• 10 section along the line XX in the second embodiment of a centrifuge cup according to FIG. 11,
• 11 shows a sectional view of the centrifuge cup in the second embodiment according to section XI-XI in FIG. 12,
• 12 side view of the centrifuge cup according to FIG. 11 in the direction of arrow XII,
• 13 top view of the centrifuge cup according to FIG. 11 in the direction of arrow XIII,
• 14 section along the line XIV-XIV in Fig. 12,
• 15 side view of the metal part,
• 16 is a side view of the metal part according to FIG. 15 rotated by 90 degrees in the direction of arrow XVI,
• 17 top view of the metal part in the direction of arrow XVII in FIG. 15,
• 18 side view of the hood in the second embodiment,
• 19 side view of the hood rotated by 90 degrees according to arrow XIX in FIG. 18,
• 20 detailed representation of the flap of the hood according to FIG. 19,
• 21 bottom view of the hood according to arrow direction XXI in FIG. 19.

In a preferred embodiment of the present invention, the plastic material of the centrifuge cup consists of a polyamide with 35% glass fiber. 1 to 4 show the centrifuge cup 1, together with the metal part (insert part) 2, while FIGS. 4 to 6 show the metal part 2 in isolation. The metal part consists of a high-strength light metal (stainless steel).

In connection with FIGS. 1 to 3 with the representation in FIGS. 4 to 6 it can be seen that the inserted metal part 2 is completely surrounded or encapsulated by the plastic material and from the outside (with the exception of of radius 14) is no longer visible. 1 to 3, the metal part 2 is shown in dashed lines. On two sides of the centrifuge cup 1, receiving grooves 3 are provided for inserting the hanging pins of the suspension of the centrifuge.

The not shown pins of the suspension of the centrifuge are inserted in the direction of arrow 24 in the receiving groove 3. In the area of the receiving groove 3, the metal part 2 is set back according to FIG. 2, so that the receiving pin finally rests on the underside 5 of the upper boundary 4 of the metal part 2. The radius 14 of the boundary 4 of the metal part 2 is adapted to the radius of the pins.

The inside of the centrifuge beaker is made of plastic material 22 according to FIG. 2. In order to prevent the metal part from shifting in relation to the injection mold during the spraying process, the metal part according to FIGS. 2 and 4 is provided with bores 13 in its base area through the centering pins grip the mold so that the metal part 2 remains centered in the injection mold.

The upper opening of the centrifuge cup 1 has two opposite recesses 6 in the side walls of the centrifuge cup 1, into which a correspondingly assigned tab 8 of the hood 9 engages. The hood is made of a polycarbonate plastic.

The tab 8 here consists of an outer part 11 and an enlarged inner part 10. The inner part 10 lies on the inside of the centrifuge cup 1 against a recessed edge 7, while the outer part 11 can be provided with corresponding corrugations in order to be able to be gripped and pulled out to facilitate the hood 9 from the opening of the centrifuge cup 1. In addition, the hood 9 also has a peripheral edge 12, which bears sealingly on the assigned surfaces of the centrifuge cup 1. As a result, the hood sits absolutely tight, and you no longer need to use a co-rotating wind boiler, because the tightly closing hood prevents harmful aerosol formation of the centrifuged material during the centrifuging process.

4 to 6, the metal part (insert) is shown separately. It is important here that the metal part 2 is designed as a simple U-profile with side legs 18, 19. The legs 18, 19 have recesses 20, 23 in the region of the receiving groove, the lower recess 20 of greater width merging with a shoulder 17 into a narrowed region 21 of the recess 23, the upper limit 4 of which closes with a radius 14. The pin of the suspension of the centrifuge then lies against this upper limit 4 and at this radius 14.

The centrifuge cup 31 shown in FIGS. 11 to 14 in turn has a metal part 32 embedded in the plastic material. The metal part 32 is embedded in the plastic material 52 of the centrifuge cup 31 in such a way that in the bottom area according to FIG. 11, the metal part 32 is only separated by a thin layer of plastic material 52 and forms the bottom of the centrifuge cup 31. The centrifugal force generated by the centrifugal material is transferred to this base in the direction of arrow 53, where it is transmitted via the legs 48, 49 (see FIG. 15) of the metal part to the receiving groove 33 on both sides of the legs 48, 49. According to FIGS. 12 and 16, the mounting pin 33 of the centrifuge hanger bears in the receiving groove 33, the radius of the pin corresponding to the radius 14 at the upper limit 34 of the receiving groove 33.

In order to achieve better embedding of the metal part 32 in the plastic material 52 of the centrifuge cup 31, the metal part according to FIGS. 15, 16 and 12 is provided with bores 43, so that the plastic material 52 passes through the bores from the inside of the centrifuge cup in the direction of the outside and as a result, the metal part is shot through or penetrated by "plastic bolts".

The hinge pin of the centrifuge suspension, not shown, is inserted in the direction of arrow 24 into the receiving groove 33, where it then lies against the underside 35 of the metal part. It is essential that the receiving groove 33 is formed by an indentation 46 of the metal part 32 in the region of the receiving groove 33 (see FIGS. 15 and 16), so that the highly loaded upper boundary 34 of the receiving groove 33 (underside 35) is made of the embossed material of the metal part 32 exists. This results in an extremely highly loaded, dimensionally stable construction of the receiving groove 33, which can also transmit the highest centrifugal forces.

To further increase the dimensional stability of the metal part 32, beads 47 are provided in the bottom region of the metal part according to FIGS. 15 and 16 at a distance parallel to one another, which also extend partially into the lower region of the legs 48, 49 according to FIG. 16.

This has the advantage that the beads 47 improve the dimensional stability and that, based on a metal part of the same strength without beads, the present metal part with beads can be made much thinner and thus lighter.

In the upper area near the peripheral edge 37, the centrifuge cup 31 is made of plastic material 52, which results in the advantage that the peripheral edge 37 can be formed from plastic material with corresponding projections (see FIG. 10).

In the exemplary embodiment shown, the peripheral edge 37 has a projection 44 which is assigned to a projection 50 on the hood 39 pointing in the opposite direction, as shown in FIGS. 18 to 21.

The upper peripheral edge 37 of the centrifuge cup is provided on two opposite sides with a recess 36 into which the tab 38 of the hood 39 shown in FIGS. 18 and 19 engages. This tab is seated with the inner part 40 on the inside of the recess 36, while the contour of the outer part 41 of the tab corresponds to the shape of the recess 36 according to FIG. 11.

The outer part 41 has, according to FIG. 20, grip grooves 51 so that the hood 39 can be pulled off the centrifuge cup particularly easily. This takes place in that the grip grooves 51 are pressed inwards on both sides by hand, as a result of which the projection 50 on the tab 38 disengages from the projection 44 on the edge 37 of the centrifuge cup 31 and the latching connection is thereby eliminated.

The circumferential edge 42 of the hood 39 arranged in the area outside the tabs 38 is overlapped by a collar according to FIG. 18, the edge 42 being assigned an associated edge 54 on the upper side of the centrifuge cup 31. The collar 55 of the hood 39 then sits on the top of the centrifuge cup as a stop, while the edge 42 of the hood 39 lies sealingly against the edge 54 of the centrifuge cup 31.

The design of the receiving groove 33 as an indentation 46 can be produced particularly simply if the metal part 32 has a bend 45 in the region of the lower open end of the receiving groove 33 and then extends upwards with a greater width.

The advantages of the two exemplary embodiments described can be seen in particular in the fact that it has surprisingly been possible to produce a high-strength and heavy-duty centrifuge cup which is considerably lighter in weight than the previously known centrifuge cups, which either consist of a preformed compact or are made of full material. The manufacture of the centrifuge beaker using the injection molding process, with the metal part being inserted directly into the injection mold and embedded in the plastic material, results in particularly low manufacturing costs. The creation of a load-transmitting connection from the receiving groove on one side over the bottom area to the receiving groove on the other side, which is carried out solely by the metal part, results in a centrifuge cup that can withstand even the highest loads with such a weight saving as was not previously thought possible .

Claims (13)

1.Centrifuge beaker for hanging on the spigot of the centrifugal head of a centrifuge, the wall of which in the area of the mounting of the spigot on the centrifuge beaker each have a receiving groove, characterized in that the centrifuge beaker (1, 31) consists of a plastic material and a metal part (2 , 32) is embedded. 2. Centrifuge cup according to claim 1, characterized in that the metal part (2, 32) is designed as a U-profile, the legs (18, 19 or 48, 49) of which are arranged parallel to the receiving groove (3, 33) and on the legs (18, 19 or 48, 49) a holder for receiving the pin of the centrifuge is provided, (Fig. 1-6 and 11-17). 3. Centrifuge beaker according to claim 2, characterized in that the holder arranged on the legs (18, 19 or 48, 49) as a recess (20, 23) running parallel to the receiving groove (3, 33) in the legs (18, 19 or 48, 49) is formed, the upper limit (4, 34) is provided with a radius (14) which is adapted to the radius of the pin, (Fig. 1-6 and 11-17). 4. Centrifuge beaker according to claim 1 to 3, characterized in that the recess (20) in the legs (18, 19) of the metal part (2) opens from the bottom region rising into a recess (23) of smaller width, the width of which is a small Dimension is larger than the diameter of the pin engaging in the recess (23) (FIG. 5). 5. Centrifuge cup according to one or more of claims 1 to 4, characterized in that the metal part (2) in the region of the free ends of the legs (18, 19) the recesses (20, 23) incorporated in the legs (18, 19) has, which are embedded in the plastic material of the centrifuge cup (1), (Fig. 1 - 6). 6. Centrifuge cup according to claim 5, characterized in that the centrifuge cup (1, 31) has a removable hood (9, 39) which with side tabs (8, 38) in associated recesses (6, 36) of the centrifuge cup (1, 31) engages sealingly (Fig. 7-9 and 17-21). 7. centrifuge cup according to claim 5 and 6, characterized in that the centrifuge cup (1, 31) has on its open side a stepped peripheral edge (7, 37) with an associated edge (12, 42) of the hood (9 , 39) cooperates, (Figs. 7-9 and 17-21). 8. centrifuge cup according to one of claims 1 to 7, characterized in that the metal part (2) consists of a high-strength stainless steel. 9. centrifuge cup according to one of claims 1 to 8, characterized in that the plastic material of the centrifuge cup (1, 31) consists of a glass fiber reinforced polyamide. 10, centrifuge cup according to claims 2 or 3, characterized in that the metal part (32) consists of a U-profile, the legs (48, 49) in the region of the receiving groove (33) have outward-pointing bends (45) into which the receiving groove (33) is formed as an impression (46) (FIGS. 15-17). 11. Centrifuge cup according to claim 10, characterized in that to increase the strength of the metal part (32) this is provided at least in the bottom area with beads (47). 12. centrifuge cup according to claim 11, dad ur ch in the _s more beads (47) parallel to one another in the bottom region and in the region of the two legs (48, 49) are provided (Fig. 15 - 17). 13. Centrifuge cup according to claim 6 or 7, characterized in that for the latching connection between the hood (39) and the peripheral edge (37) of the centrifuge cup (31) at least on the lower part of the tab (38) of the hood (39) a projection (50) is arranged, which engages behind an associated projection (44) on the edge (37) of the centrifuge cup (31), (Fig. 10, 20).

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