DE3101078A1 - Centrifuge - Google Patents

Abstract

The invention provides a centrifuge such as is used, for example, for the lavage of blood. The centrifuge comprises a rotor which can be rotated about a vertical axis of rotation, and, arranged on the rotor at a certain distance from the axis of rotation of the rotor, at least one test-tube holder for an essentially cylindrical test tube which has an open mouth. The test-tube holder can be pivoted between a centrifuging position, in which the test tube is inclined upwards and inwards, and a decanting position in which the test tube is oriented with respect to the axis of rotation in such a way that supernatant liquid can be decanted from the test tube by the centrifugal force. In the decanting position of the test-tube holder, the radially outermost generatrix or generating line (17A) of the inside of the test tube (17) is tangent to an imaginary cylinder surface (G), concentric with the axis of rotation (A) of the rotor, at a point (F) which is at a certain distance from the bottom of the test-tube (17), and it encloses, with the plane (C, D) containing the axis of rotation (A) of the rotor and the tangent point (F), an angle ( gamma ), which is preferably greater than 45 DEG . <IMAGE>

Description

T ₁ ___, -_ _, Dili., ·., - »- If ....._ patent attorneys and

IEDTKE * ÖÜHLINQ - I \ INNE Ve.treter at the EPO

GO Dip) -Inn H.T1edtke

RUPE - Pellmann ^ ,. "cL, g.sawing

-3- Dipl.-Ing. R. Kinne

Dipl.-Ing. R Group Dipl.-Ing. B. Pellmann

Bavariaring 4, P.O. Box 20 24 8000 Munich 2 Tel .: 089-539653 Telex: 5-24845 tipat cable: Germaniapatent Münche

January 14, 1981

DE 0973 / case U / Z. 19881 BN / vb

SEPAREX TEKNIK AB

Stockholm / Sweden

centrifuge

The invention relates to a centrifuge with a rotor rotatable about a vertical axis of rotation and

at least one sample tube holder for a one provided on the rotor at a distance from the axis of rotation Open mouth, essentially cylindrical Sample tube, the sample tube holder between a centrifugal position in which the sample tube after is inclined above and inside, and a decanting position is pivotable in which the sample tube so to The axis of rotation is oriented so that the excess liquid can be decanted from the sample tube by centrifugal force is.

Centrifuges of this type are described in DE-AS 1 698 262 and DE-OS 1 598 369 (= US-PS 3 401 876) known and are used in particular for washing blood cells in the so-called Coombs test and similar purposes - used, normally several samples at the same time in arranged along a circle on the centrifuge rotor Test tubes are treated.

130067 / 0S (H.

Ut ₉ CBnK (Mo _n C _{8 n,} K, _0. 5 "6,070 0 ™" ™ * Ban, Munich, K _10. 3,939,844, "^ _{(Münehen) Where."} ""

DE 0973

Performing the Coombs test requires washing one of the red blood cells made up of red blood cells several times Sample in physiological saline solution. With every washing process, the water suspended in the washing liquid is Sample taken up in a sample tube by centrifugation into a blood cell fraction and a lighter washing liquid fraction separated, after which the washing liquid with impurities contained therein is decanted from the sample tube. 10

Both spinning and decanting are carried out in the centrifuge rotor, and during the Hurling the sample tube is inclined inward and upward so that the blood cells pass through the '** Centrifugal force must be pressed to the bottom of the sample tube. In the known centrifuges, decanting takes place in that the sample tube is subjected to centrifugal force when rotating the rotor is pivoted radially outward into an approximately vertical position, with the

9Π · ■

^ ^w Effect of centrifugal force and against the force of gravity the excess liquid emerges from the upper end of the sample tube.

When decanting, on the one hand, the protruding

Drain off the washing liquid as completely as possible, while on the other hand there is a loss of red blood cells (which is very small compared to the washing liquid Occupy volume) with the draining washing liquid is to be avoided as far as possible. This condition is capable of

known centrifuges are difficult to perform.

The invention is based on the object at a To enable centrifuge of the type specified at the outset to be able to decant accurately.

The centrifuge according to the invention is for the solution

this task characterized in that

130067/0504

DE 0973

-ι decanting position the radially outermost generating the On the inside of the sample tube, an imaginary circular cylinder surface that is concentric with the axis of rotation of the rotor one at a distance from the bottom of the sample tube

_ Place tangent and an angle with which the rotor axis of rotation and includes the plane containing the tangent point.

As a result, a certain volume is retained in the sample tube in the decanting position, and although in an area close to the bottom of the sample tube that extends outwards through the inside of the sample tube and inwards through the imaginary circular cylinder surface is limited. The volume can be precisely matched by suitable • choice of the tangent point brought up to the volume that one wishes to retain in the sample tube, d. H. with the Volume of blood cells washed. According to the invention, the retained volume thus becomes close compressed to the bottom, while in the known centrifuges it spreads over the entire length of the sample tube will.

In principle, centrifugal force can be used to pivot the sample tube into the decanting position as is done in the known centrifuges. In a preferred embodiment takes place but the pivoting of the sample tube between the spinning position and the decanting position by means of a Mechanism that can be actuated from the outside while the rotor is rotating and that holds the sample tube holder with an actuating member connects.

In the following description, the invention is based on an exemplary embodiment shown in the drawing explained in more detail. Show it:

Fig. 1 in side view, partially in vertical axial section, a formed according to the invention

130087/0504

DE 0973

Centrifuge _f where the sample tube holder and sample tube are shown in the spinning position;

FIG. 2 is a side view similar to FIG. 1 with sample tube holders and sample tubes in FIG Decanting division; and

3 shows a plan view of the rotor along the line III-III of FIG. 1, but with only one sample tube holder and the associated sample tube are shown in the spin position, while the rest Sample tube holder and sample tube are shown in other positions.

As can be seen from Fig. 1, the centrifuge has a housing 11 which has an electric motor in its lower part 12 with a vertically arranged shaft 13 receives. In its upper part, which is closed by a hinged cover 14, the housing 11 takes one cup-shaped Rotor 15 on. The rotor 15 is rotated by the motor around the vertical axis of rotation A at a speed from Z. B. 3000 to 5000 revolutions per minute driven.

On the rotor 15, four cup-shaped trial ¹ tube holder 16 are located around these at a distance from the rotational axis A and with uniform distribution. A circular cylindrical sample tube 17 with a round bottom is detachably inserted into each sample tube holder, the bottom of the sample tube being supported on the bottom of the sample tube holder.

The sample tube holder 16 are each on one

° inclined at an angle of about 45 ° to the horizontal Shaft 18 attached. The shafts 18 are rotatable in the Rotor 15 mounted, the axes of rotation B in pairs in

130067/0504

DE 0973

two vertical, im. standing at right angles to one another and containing the rotor axis of rotation A / d. H. radial Levels C, D (Fig. 3) lie. In addition, the axes of rotation B of the shafts 18 are each at right angles to Longitudinal axis E of the associated sample tube 17.

By rotating the shafts 18, the sample tube holder 16 can thus be mi _: t. the sample tube 17 are pivoted, namely between a position in which the longitudinal axes. E ^ incline upwards and inwards, as can be seen from FIG. 1, and a position, hereinafter referred to as the decanting position, in which the longitudinal axes E are essentially horizontal, as can be seen from FIG. The sample tube holders are pivoted together by an adjusting mechanism which can be actuated outside the housing 11 both when the rotor 15 is stationary and when it is rotating. This adjustment mechanism is described in detail below.

Each sample tube holder 16 is in the decanting position by a torsion spring 19 arranged around the shaft 18 biased and over a metal wire 20 attached to the circumference of the shaft 18 with a sleeve connected, which is vertically displaceable on an upwardly extending central rotor extension 22 and turns with the rotor. A compression spring 23 loads the sleeve 21 and is dimensioned so that it the total force of the torsion springs 19 can overcome.

3 "The sleeve 21 therefore tries to pivot the sample tube 16 against the force of the torsion springs 19 into a position in which the longitudinal axis E is at an angle with the radial plane C or D containing the axis of rotation B of the respective associated shaft 18

includes, on the side of this plane which faces away from the decant position

13-0067./0604

DE 0973

' is. This position is referred to below as the loading position and is assumed when the cover 14 is opened, whereby the spring 23 moves the sleeve 21 into an upper position, fixed by a projection 24 Moves end position. In the loading position, which is shown in the right part of FIG is, the sample tubes 17 in a convenient manner in the sample tube holder 16 is inserted and removed from it again.

The sleeve 21 can both with the stationary and rotating rotor 15 by one on the Upper side of the lid, 14 provided, motor-driven cam 25 can be moved downwards.

o _he cam 25 acts on the sleeve via a vertical plunger 28 which is loaded with a cam roller 27 and is loaded against the cam by a spring 26 " 29 wears.

The lower end edge 31 of the pressure ring has a wavy shape and is against the correspondingly wavy

upper Stinrkante 32 of the sleeve.21 supported. If nc ....- ■

the pressure ring 29 over, den.stössel 28 against the sleeve 21 is pressed, is a frictional rotary connection brought about by the compression spring 23 between the Pressure ring and the sleeve present, whereby the pressure ring rotates when the sleeve rotates. The arrival

pressing of the pressure ring against the sleeve takes place when a part 25A of the cam 25, on the roller 27 the The plunger 28 is pushed down slightly at the bottom holds, as shown in FIG.

Here, the Proberöhrcherhalter be held in a position 16, in which the longitudinal axis E ß a 'small angle with the radial plane C and D includes, and

1S0067 / OB04

DE 0973

on the side of this level facing the decanting position. This position, hereinafter referred to as Is referred to the spin position is shown in the lower part of FIG.

The pressure ring 29 is at its upper front edge

33 formed with a conical friction surface. He can by the force of the spring 26 on the ball bearing 30 against a correspondingly conical friction surface 34 on the underside of the cover 14 attached brake ring 35 are pressed to a frictional rotary connection between the pressure ring and to manufacture the stationary brake ring. When the rotor 15 and thus the sleeve 21 rotate, will the sleeve move quickly up and down because of the wavy front edges 31, 32, whereby the sample tube holder 16 with the sample tube 17 accordingly be swiveled quickly back and forth about the axes B. This pivoting, which takes place around a central position, in which the longitudinal axis E lies in the radial plane C or D - cf. the illustration in the left part 3 - has the purpose of intimately mixing the contents of the sample tube 17. The pressure of the Pressure ring 29 against the brake ring 35 takes place when a part 25B on the cam 25 of the roller 27 is opposite, wherein the cam is lifted from the roller.

The decanting position is assumed when a nose 25C on the cam 25 over the plunger 28 and the pressure ring 29 presses the sleeve 21 down so that the wires 20 allow the springs 19, the sample tube holder 16 to pivot with the sample tube 17 approximately to the horizontal, see. Fig. 2 and the upper part of Fig. 3. In the decanting position

are the mouths of the sample tubes 17 each a protrusion 36 on the inside of a

130067/0604

DE 0973

cylindrical wall 37 of the rotor 15 opposite. The projections 36 are used in the decanting position ejecting the sample tubes 17 from the sample tube holders 16 to prevent.

As can be seen from FIG. 3, the radially outermost generatrix 17A is tangent in the decanting position, d. H. the radially outermost surface line, the inner surface of the sample tube, lying horizontally in this position 17, an imaginary circular cylindrical point F at a distance from the bottom of the sample tube Area G, the axis of which coincides with the rotor axis of rotation A. Near the bottom of the sample tube This results in an area H in the sample tube, which extends outwards through the inside of the Sample tube and is limited inwardly by the cylinder surface G and in which the centrifugal force qresser is than at the tangent point F.

A distribution container 38 for washing liquid attached to the sleeve 21 is open at the top and has four nozzles lying in the radial planes C, D. 39 on. These spouts 39 are at the level of the open mouths of the sample tubes 17 when they are in the mixed position according to the left part of the Fig. 3 are located so that washing liquid can be fed into the sample tube by centrifugal force. Predefined amounts of washing liquid can be supplied via a pipetting tube 40 from a

^ "arranged pipetting device 41 to the distribution container 38 are fed. As can be seen from Fig. 1, the one end on the circumference of the Shafts 18 attached wires 20 attached to the distribution tank 38 at their other end.

When carrying out the washing for the Coombs test, the test tubes with

138067 / OS04

DE 0973

guided rehearsals, ζ. B. a pair of drops of a blood sample diluted by saline solution opened cover 14 and stationary rotor 15 inserted into the sample tube holder 16. the Sample tube holder 16 are located here in the loading position shown in the right part of FIG.

After the cover 14 has been closed it begins the rotor 15 to rotate with the cam portion 25B facing the roller 27 so that the sample tube holder 16 with the sample tube 17 back and forth be pivoted about the middle position shown in the left part of FIG.

\ 5 device 41 a certain amount, z. B. 10-20 cm ³ of washing liquid is fed into the distribution container 38. The pivoting movement is quite small, so that the mouths of the sample tubes are always opposite the nozzles 39. Due to the centrifugal force, a certain amount, namely a quarter of the total amount supplied by the pipetting device, of washing liquid is fed into each sample tube 17, and the rapid pivoting of the sample tube holder with the sample tubes causes the samples to be intimately mixed with the washing liquid. During the mixing, the rotor 15 can expediently be driven at a low speed.

After mixing is complete, the cam 25

·

further rotated until the cam portion 25A over the The plunger 26 and the pressure ring 29 presses the sleeve 21 down so that the sample tube holder 16 with the Sample tubes 17 assume the spin position according to FIG. 1 and the lower part of FIG. The rotor

15 is then driven at full speed to the Place the contents of the test tube in a heavy blood cell

130067/0504

DE 0973

fraction S and a lighter or protruding one consisting of washing liquid and impurities To separate liquid fraction W, see. Fig. 1.

When the separation is complete, the cam 25 is rotated further, while the rotor is still rotating, in order to pass through the nose 25C to press the sleeve 21 down so far, that the sample tube holder 16 with the sample tube 17 that shown in FIG. 2 and the upper part of FIG Take up the decanting position. The supernatant liquid is removed by the centrifugal force Test tube ejected; it is caught by the rotating rotor wall 37 and later at stationary rotor 15, via an outlet opening 42 in the rotor base and a discharge line 43 derived. In the sample tube 17, only that remains in the area H (Fig. 3) located material, i. H. essentially only the blood cell fraction S, back.

After decanting, the cam 25 is rotated further until the cam part 25b is opposite again the roller 27 comes to rest so that the sample ■ tubes again assume the mixing position can. In this position, washing liquid is returned to the sample tube in the manner explained above, fed and mixed with the now washed blood cells. The new washing process plays in the manner described. The second washing process is followed by at least a third washing

Occurrence. After decanting during the last wash, the remaining in the sample tubes can be Blood cells undergo the usual examination.

The volume of the material retained in the sample tube can be determined by a suitable choice

1 30D67 / OS04

DE 0973

the sample tube dimensions and the position of the tangent point F relative to the bottom of the sample tube · exactly fixed and can be kept within tight tolerances. It should be noted that the volume of the retained Material does not suffer from the usual and difficult to avoid inaccuracies of the sample tube shape is influenced in the area of the mouth, as is the case with the known centrifuges Case is.

Although the drawings show the now preferred embodiment of the centrifuge according to the invention, this embodiment is only an embodiment. In another, not shown embodiment The form of management is the mixing of the contents of the test tubes in a manner known per se (DE-OS 1 598 369) by rotating the sample tubes about their longitudinal axes when the centrifuge rotor is rotating. In this * embodiment, however, any sample tube is preferred rotated by its own drive in its sample tube holder. This is on the rotor in the area Each sample tube holder is provided with a friction roller, which is driven by the rotor drive motor via a gear unit and in the mixing position the sample tube holder is in frictional engagement with the one assigned to it Sample tube stands. In this embodiment, the sample tubes can therefore be more advantageous Way are rotated fairly slowly, while in known centrifuges the sample tubes very quickly to be turned around.

Other modifications are also possible within the scope of the invention. So when hiring the need Put the sample tube holder in the decanting position

cannot be swiveled horizontally.

190067/0504

If, for example, more than four sample tube holders are provided, it may be useful, taking into account the space requirements, to choose the angle "£ between the plane C, D and the longitudinal axis E of the sample tube less than 90 °, so that the mouth area of each sample tube in the tilted position In order that the retention area H is not widened over an excessively long section of the sample tube, the angle V ^ should be kept as large as possible and it is preferably never smaller than 45 °, for example.

130067/0504

Claims (6)

Claims 1. Centrifuge with a rotor rotatable about a vertical axis of rotation and at least one sample tube holder provided on the rotor at a distance from the axis of rotation for an essentially cylindrical sample tube having an open mouth, the sample tube holder being pivotable between a centrifugal position in which the sample tube after is inclined at the top and inside, and a decanting position in which the sample tube is oriented to the axis of rotation so that the excess liquid is decantable by centrifugal force from the sample tube, characterized in that in the decanting position, the radially outermost generating line (17A) of the The inside of the sample tube (17) is tangent to an imaginary circular cylinder surface (G) concentric with the rotor axis of rotation (A) at a point (F) at a distance from the bottom of the sample tube (17) and an angle {- *) with which the / 2 γ 0973 ι rotor axis of rotation (A) and the tangent point (F) containing plane (C, D). - 2. Centrifuge according to claim 1, characterized in that the sample tube (17) in the decanting position an angle smaller than 45 ° to the horizontal and is preferably approximately horizontal. 3. Centrifuge according to claim 1 or 2, characterized characterized in that the sample tube holder (16) by one Pivot axis (B) is pivotable, which lies approximately radially to the rotor (15). 4. Centrifuge according to claim 3, characterized in that the pivot axis (B) is substantially at right angles to the longitudinal axis (E) of the sample tube (17). 5. Centrifuge according to one of the claims 1 to 4, characterized in that the tube holder (16) has a power transmission mechanism (18,19,20,39,21) with an outside of the rotor (15) actuatable control device (25,26,27,28,29,30) is connected. 6. Centrifuge according to claim 5, characterized in that the power transmission mechanism (18,19,20,39,21) controllable when the rotor (15) is rotating is.
30th 300B7 / 0BD4