WO2018197592A1

WO2018197592A1 - Sseparation body

Info

Publication number: WO2018197592A1
Application number: PCT/EP2018/060655
Authority: WO
Inventors: Mark WEINSTOCK; Christian Wegener; Ulrich KARRENBERG
Original assignee: Sarstedt Aktiengesellschaft & Co. Kg
Priority date: 2017-04-26
Filing date: 2018-04-26
Publication date: 2018-11-01
Also published as: DE102017108941A1

Abstract

The invention relates to a separation body (100) for separating a first phase of a liquid from a second phase in a tubular container. The separation body has a float (110) made of elastic material having a circumferential sealing edge (112) and at least one ballast body (120) fastened to the underside of the float. The density of the ballast body (120) is greater than the density of the float (110), and the density of the entire separation body (100) lies in a range of values between the density of the first phase and the density of the second phase of the liquid. In order to ensure that the separation body is released from an initial position in the container only in a controlled manner under a predetermined force action, the invention provides that at the end facing away from the float (110), the ballast body (120) has a predetermined static friction coefficient on the surface of the ballast body, or at least one adhesive element (122), which has the predetermined static friction coefficient on the surface of the adhesive element.

Description

separating body

The invention relates to a separating body for separating a first from a second phase of a liquid in a tubular container. In particular, separators are meant to separate blood serum as the first phase of blood cake as the second phase in blood as a fluid within a blood collection tube.

In the prior art, blood collection tubes with separating bodies are basically known. In the delivery state of the blood collection tubes, the separating bodies are fixed in a starting position. When blood flows into the blood collection tube via an inlet, blood flows or flows through the separator; In any case, in the initial position, the separator does not provide a seal for the blood within the blood collection tube. For medical analysis, it is necessary for the blood to be separated into two components, blood serum and blood cake. For this purpose, the blood collection tube is centrifuged with the blood therein. The heavier blood cake then settles due to centrifugation in the near-bottom volume region of the blood collection tube, while the lighter blood serum floats on the blood cake. Under the action of the centrifugal force, the separator separates from its original position and moves to a sealing position. Because the density of the entire separating body is in a range of values between the density of the blood serum and the density of the blood cake, the separating body automatically positions itself exactly at the phase boundary between blood serum and blood cake. This position is also called sealing position, because the separating body in this position sition with its sealing edge circumferentially sealing against the inside of the tubular sample tube and thus cleanly separates the blood serum from the blood cake. The separating body maintains this sealing position even after the end of the centrifuging, so that the blood serum and the blood cake are separately available for a laboratory examination.

Separators are disclosed, for. In international patent application WO 2010/132783 A1. The separating bodies described therein each have a floating body made of elastic material with a peripheral circumferential sealing edge in plan view, wherein the sealing edge is formed for sealing engagement on the inside of a tubular sample container in a sealing position. At the bottom of the float, a ballast body is attached in each case. The density of the ballast body is in each case greater than the density of the floating body and the density of the entire separating body lies in a range of values between the density of the first phase and the density of the second phase of the liquid.

The invention has the object of developing a known separating body for separating a first of a second phase of a liquid in a tubular container and a corresponding known container to the effect that a release of the separating body from a starting position in the container is controlled only at a predetermined force ,

This object is achieved with regard to the separating body by the subject of claim 1. Accordingly, the separating body is characterized in that the ballast body at its end facing away from the floating body has a predetermined static friction coefficient on its surface or that the ballast body has at its end remote from the float at least one adhesive element having on its surface the predetermined static friction coefficient. The predetermined static friction coefficient is dimensioned such that the Release body only under the action of a force, in particular a centrifugal force from a starting position in the delivery condition triggers when the force is greater than a predetermined force threshold.

In the delivery state or in its initial position, the separating body is releasably clamped in the tubular container. He then sits across the container. In this case, the ballast body presses with its end facing away from the float against the inside of the tubular container. In other words, the separating body is supported in this initial position as described against the tubular container. Under the action of a force, in particular the centrifugal force, the separating body is to be released from its starting position and migrate into the sealing position described above. However, this release from the starting position should only take place when the force on the separating body is greater than the predetermined force threshold; in particular, the release from the starting position should not take place at the wrong time, for example, not when the tubular container with the separating body therein experiences a shock during transport in the starting position. On the one hand to safely ensure the desired release of the separating body from its initial position and on the other hand to prevent unwanted release of the separating body from the starting position, the present invention provides that a predetermined stiction between the ballast body and the inside of the tubular container is adjusted.

For realizing this predetermined stiction, the present invention claims two alternatives: Firstly, a predetermined static friction coefficient can be realized on the surface of the ballast body facing away from the floating body; ie the surface of the ballast body is then formed there with the appropriate static friction coefficient. Alternatively, the ballast body at its end facing away from the float also have at least one adhesive element with the predetermined static friction coefficient. Ie. in this case then has the surface of the adhesive element, the predetermined static friction coefficient. The predetermined coefficient of static friction is matched to the coefficient of friction of the inside of the tubular container, against which the ballast body or the adhesive element rests in the starting position. Only the interaction of the coefficient of static friction on the ballast body or the adhesive element and the (adhesive) friction coefficient on the inside of the container defines the force required to release the separating body from the starting position.

In general, the density of the second phase of the liquid is greater than the density of the first phase of the liquid. For blood as a fluid, this means that the blood cake as the second phase has a greater density than the blood serum, which corresponds to the first phase. After a centrifugation, therefore, the blood serum floats on the blood cake. The density of the entire separator 100 is in a range of values between the density of the first phase and the density of the second phase of the liquid. Therefore, the separating body always positions itself in the sealing position on the phase boundary between the two phases.

Unless otherwise stated, the separator is described below in a normal position. In this normal position, the ballast body is arranged below the float. The center of gravity of the float, the center of gravity of the ballast body and the center of gravity of the entire separation body are all on a vertical line. The terms used below, such as vertical, horizontal, below, side view and top view, etc., all refer to this normal position. The sealing position corresponds to the normal position with vertical tubular container.

According to first embodiments, the adhesive element of the same material as the float and preferably formed integrally with the float. The adhesive element is then advantageously manufactured in terms of production technology. inexpensive and easy to implement. The one-piece training with the

Float, for example, can be easily realized by small channels are provided in an injection mold for the separator on the outside or inside the ballast body, which connect the float with the adhesive element. During injection molding of the floating body, the material of the floating body is then injected through the channels into the cavities for the adhesive elements. After removal of the injection mold, the material of the float remains in the region of the channels of the injection mold on the outside or inside the ballast body in the form of webs obtained, which connect the float body with the adhesive element in one piece. The bars are only optional. The float and the adhesive elements can also be formed independently of each other as individual elements, but this is technically more complex.

According to a further embodiment, the floating body may be disc-shaped, while the ballast body is in the form of a plurality of fingers, which extend from the underside of the disc-shaped floating body - distributed at the edge - away. This design of the ballast body in the form of fingers ensures that the separator does not seal the tubular container in its initial position in the delivery condition for the liquid, but that the separator can be flowed around by the liquid flowing into the container, so that the liquid in the below Separator located volume of the tubular container can flow.

As an alternative to a disk shape, the float can also be designed in the shape of a ball or pot.

Finally, the ballast body may be made of a material which is less elastic than the material of the float or the material of Membrane. This is true because the said sealing edge is typically attached to the float and not to the ballast body. For the function of the separating body, it is important that the sealing edge under the action of centrifugal force on the float - and thus on the sealing edge - is elastically deformable. Under the action of the force, the separating body, in particular the floating body, is narrowed, so that the sealing edge no longer abuts in a circumferentially sealing manner against the inside of the container. This makes it possible to flow around the separating body with the liquid inside the tubular container. Because the sealing edge is typically not attached to the ballast body, this elasticity is not required by the ballast body; this can therefore be less elastic.

The above object of the invention is achieved with respect to the tubular container by the subject matter of claim 8. The advantages of this solution correspond to the advantages mentioned above with respect to the separating body.

The description is attached to ten figures, wherein

Figures a separator according to the invention with disk-shaped 1a and 1b floating body according to a first variant; the separating body of Figure 1 in a tubular container; the disc-shaped separating body according to a second variant;

FIG. 4 shows the separating body according to FIG. 3 in the tubular container;

Figures show a spherical separating body according to the invention according to 5a and 5b of a first variant; FIG. 6 shows the separating body according to FIG. 5 within the tubular container;

Figure the spherical separator according to a second variant;

7a to 7d

FIG. 8 shows the separating body according to FIG. 7 inside the tubular container;

Figures show a cup-shaped separating body according to the invention; and

9a to 9d

Figure 10 shows the separator of Figure 9 within the tubular container.

The invention will be described in detail below with reference to the said figures in the form of embodiments. In all figures, the same technical elements are designated by the same reference numerals.

FIG. 1 shows the separating body 100 according to the invention in a perspective view (FIG. 1 a) and in a cross-sectional view (FIG. 1 b). The separating body 100 consists of a floating body 1 10 and a ballast body 120. The floating body 110 is disc-shaped with a thickening 113 in its center and with a peripheral sealing edge 1 12 is formed. The ballast body 20 is formed in the form of a plurality of fingers 124, which extend away from the underside of the disc-shaped floating body 1 10. The fingers 124 are arranged distributed on the edge of the ballast body. At her

Float facing away from the fingers each have adhesive elements 122 which have on their surface a predetermined static friction coefficient. As described above, this ensures that the separating body remains in its initial position or state of delivery within the tubular container until it experiences a force which is greater than a predetermined threshold force value.

The adhesive element 122 is formed in the embodiment shown in Figure 1 of the same material as the float 110 and even integrally therewith. This can be seen in FIG. 1 from the fact that the material of the

Float on the outside of the ballast body 120 is formed in the form of webs 126, which connect the float in one piece with the adhesive member 122.

FIG. 2 shows the separating body 100 according to the invention in the tubular container 200, for example a blood sampling tube. The separating body 100 can be seen, on the one hand, in its starting position 210, in which it is located when the tubular container 200 is delivered. In this initial position, the separating body is supported by said adhesive elements 122 on the inside of the tubular container. Only under the action of the centrifugal force, the separating body 100 is released from its initial position 210 and moves to the sealing position 220. In this case, it rotates by 90 °. Only when the separating body 100 is no longer under the action of centrifugal force, he deforms back to its original state. Its sealing edge 1 12 is then in the sealing position 220 in the circumferential direction R everywhere sealing against the inside of the tubular container 200 and separated in this way the two phases of the liquid or the blood effectively from each other.

FIG. 3 shows the separating body 100 according to the invention in an alternative embodiment. FIG. 3a shows it in a perspective view, and FIG. 3b shows it in a side view. Again, the float 1 10 is basically disc-shaped, but it is spherically deformed. Therefore, the circumferential edge 1 12 viewed from the side is wavy with troughs 1 18 and Wel- lenbergen 1 17 trained. From the underside of the disk-shaped floating body 110, 18 ballast bodies 120 in the form of fingers 124 project downward, in each case in the region of the wave troughs. Preferably, each of these fingers has at its end facing away from the float 110, the said adhesive element 122 on. In the area of the wave crests 1 17 material accumulations are formed on the top of the disc-shaped float; These act as additional buoyancy bodies 1 13. The fingers 124 and the buoyancy bodies 1 13 are arranged alternately distributed in the embodiment shown in Figure 3, each with a circumferential angular distance of <p = 90 ° at the periphery of the disc-shaped float. This special arrangement of buoyancy bodies and ballast bodies causes under the action of a force, in particular the centrifugal force, that the floating body 1 10 deforms even more spherical. This is because then the buoyancy of the buoyancy body 1 13, the wave crests 1 17 still further pulls up and because at the same time the fingers 124 of the ballast body in the troughs 1 18 are pulled down further. Due to this even stronger spherical deformation slimming the separator 100 and the sealing edge 1 12 of the float then no longer sealingly against the inside of the tubular container. The float can therefore, as desired, be flowed around on its way into the sealing position 220 of the liquid or the blood.

FIG. 4 shows the separating body according to FIG. 3 inside the tubular container 200. When delivered, the separating body is in its starting position 210. It then rests on the one hand with the adhesive elements 122 and on the other with the free ends of the buoyant bodies 13 on the inside of the tubular body Container 200 off. The free ends of the buoyancy bodies 1 13 are therefore preferably rounded according to the inner radius of the tubular container 200. In the starting position 210, the separating body 100 can be flowed around by blood flowing into the tubular container, so that the blood can also reach deeper volume regions of the tubular container. With regard to the behavior of the separating body 100 under the action of the centrifugal force and after switching it off, reference is made to the description for FIG. 2, which applies analogously to FIG. 4 in this respect.

FIGS. 5a) and 5b) show the separating body 100 according to the invention in a spherical configuration. It consists of the elastic float 1 10 with the circular in plan view sealing edge 112. This is not precluded that the sealing edge 112 is formed wavy in the side view of Figure 1. At the bottom of the float 1 10 a ballast body 120 is attached. At the bottom of the ballast body 120, the adhesive elements 22 can be seen. The adhesive elements are here exemplified by webs 126 integral with the

Float 1 10 connected.

According to Figure 5, the floating body 1 10 is locally narrowed. In the region of the constriction 1 14 it is designed as a membrane 1 16. The membrane is undulating with straight wave crests and troughs. Regardless or alternatively, the membrane 1 16 could also be formed of elastic material. The formation of the membrane in wave form and / or of elastic material is required to allow a spring action of the membrane. The spring effect contributes to the fact that in the sealing position, a sufficiently large pressure of the sealing edge is exerted on the inside of the container in order to effectively differentiate the two phases of the liquid against each other.

The floating body 110 has a local flattening 119 "or bead on its upper side remote from the ballast body 120. In the region of the flattening, the floating body does not lie sealingly against the inside of the container in the starting position and thus allows the separating body to flow around therewith the liquid flowing in the container. FIG. 6 shows the separating body according to FIG. 5 inside the tubular container 200. On delivery, the separating body is in its starting position 210. It then rests against the inside of the tubular container 200 on the one hand with the adhesive elements 122 and on the other hand with the surface of the floating body , In the initial position 210, the separating body 100 can be flowed around in particular in the region of the flattened portions 19 "and the ballast body of blood flowing into the tubular container because the outer contour of the separating body 100 there-seen from the inlet 230 of the tubular container-is of the pure circular shape The blood can thus also flow into deeper volume regions of the tubular container.

With regard to the behavior of the separating body 00 under the action of the centrifugal force and after switching off, reference is made to the description of FIG. 2, which applies in this respect for Fig. 6 analogously.

FIG. 7 shows the spherical separating body 100 in a further embodiment. Figures 7a and 7b show him in different side views. Figures 7c and 7d show him in different sectional views of different depths. The embodiment of FIG. 7 differs substantially only in the shape of the membrane 1 16 and in the design of the surface of the float of the embodiment of FIG. 5. Also in this embodiment, an adhesive element 122 can be seen on the underside of the ballast body 120 ,

Although the wave crests and the troughs of the membrane 1 16 are annular here, but they are oval here. Instead of the flattening, the top of the float 1 10 a survey 1 19 'on. The flattening and the elevation equally cause that in their surroundings no residues of the liquid, in particular no blood residues can accumulate, which can not escape between the separator and the wall of the container. FIG. 8 shows the separating body according to FIG. 7 in the interior of the tubular container 200. On delivery, it is supported on the inside of the tubular container 200 on the one hand with the adhesive elements 122 and on the other hand with the elevation 1 19 '. In the starting position 210, the separating body 100 can be flowed around in particular in the region of the elevation 1 19 'and the ballast body of blood flowing into the tubular container, because the outer contour of the separating body 100 there - seen from the inlet 230 of the tubular container - of the pure circular shape differs. The blood can thus also flow into deeper volume areas of the tubular container.

With regard to the behavior of the separating body 100 under the action of the centrifugal force and after its switching off, reference is made to the description for FIG. 2, which applies analogously to FIG. 8 in this respect.

FIG. 9 shows the separating body 100 in a cup-shaped design. Figures 9a and 9b show him in different side views. Figures 9c and 9d show him in different sectional views of different depths. Apart from its outer (pot) shape, this separation body differs essentially only in the circumferential sealing edge 1 12 of the separator of FIG. 7. The sealing edge 1 12 is not wavy here, but just horizontally extending. Also in this embodiment, an adhesive element 122 can be seen on the underside of the ballast body 120.

FIG. 10 shows the separating body according to FIG. 9 in the interior of the tubular container 200. Otherwise, the description of FIG. 8 for FIG. 10 applies analogously. LIST OF REFERENCE NUMBERS

100 separating bodies

1 10 floats

1 12 sealing edge

1 13 buoyancy body

117 wave mountain of the sealing edge

1 18 Wellental of the sealing edge

1 19 'local survey

1 19 "local flattening

120 ballast body

122 adhesive element

124 fingers

126 footbridge

200 tubular container

210 Starting situation or delivery condition

220 sealing position

230 inlet

R circumferential direction

S blood serum

K blood cake

φ circumferential angle

Claims

claims

A separating body (100) for separating a first from a second phase of a liquid, in particular for separating blood serum (S) from blood cakes (K) in blood as liquid, in a tubular container (200); comprising: a floating body (110) made of elastic material with a circumferential sealing edge (12) in the plan view for sealing contact with the inside of the tubular container (200) in a sealing position (220); and

at least one ballast body (120) attached to the underside of the float (110);

wherein the density of the ballast body (120) is greater than the density of the floating body (1 10); and

wherein the density of the entire separation body (100) is in a range of values between the density of the first phase and the density of the second phase of the liquid;

characterized,

that the ballast body (120) at its the float (1 10) facing away from the end has a predetermined static friction coefficient on its surface; or

that the ballast body (120) at its the float (1 10) facing away from the end of at least one adhesive element (122) which has on its surface the predetermined static friction coefficient; and

in that the predetermined static friction coefficient is dimensioned such that the separating body (100) only releases from a starting position (210) under the action of a force, in particular centrifugal force, when the force is greater than a predetermined force threshold value.

2. separating body (100) according to claim 1,

characterized,

the adhesive element (122) is made of the same material as the floating body (110).

3. separating body (100) according to claim 2,

characterized,

in that the adhesive element (122) is formed integrally with the floating body (110).

4. separating body (100) according to claim 3,

characterized,

in that the floating body (110) is integrally connected to the adhesive element (122) via a web (26), wherein the web is formed from the material of the floating body (1 10) and attached to the outside or inside of the ballast body (120) ,

5. separating body (100) according to one of the preceding claims,

characterized,

that the floating body (1 10) is disc-shaped; and that the ballast body (120) in the form of a plurality of fingers (124) is formed, which extend from the underside of the disc-shaped floating body (1 10) - distributed at the edge - away.

6. separating body (100) according to one of the preceding claims 1 to 4, characterized

that the floating body (1 10) is formed spherical or cup-shaped.

7. separating body (100) according to one of the preceding claims,

characterized,

that the ballast body (120) is made of a material which is less elastic than the material of the floating body (1 10).

8. Tubular container (200), in particular blood collection tube,

marked by

a separating body (100) having a floating body (110) and a ballast body (120) according to one of the preceding claims,

wherein the ballast body (120) in an initial position (210) with its the float (1 0) facing away from the surface or with the adhesive element (122) on the inside of the tubular container (200).