Fresenius Ag

501 Fresenius Ag

Hans-Jurgen Neumann

Artur Meisberger

Wolfram Weber

Bernd Mathieu

Device for the separation of blood with a cannula with the aid of separation in a centrifuge with a blood pump in an inlet line and a collection storage bag, which can be emptied with the aid of a pressure device into a return line. The flow resistance R.sub.o of the return line is designed so that it has preferably about half of the flow resistance of the remainder of the return system. In a return/recirculation phase, the blood pump is operated at a predetermined recirculation flow rate F.sub.R, whereby a predetermined cannula infusion flow rate F.sub.N is established as a function thereof.

Blood separation device

The invention relates to the control of a system in a blood centrifuge for separating the constituents (fractions) of the whole blood taken from a donor 'in vivo' and provided with anticoagulants. A control is provided which as input quantity includes a signal on the flow rate of the full blood and on the output side is connected to the speed setting means for the blood centrifuge. The transfer function of the control is so defined that on a change of the full blood flow the speed of rotation is set so that the volume ratios of the blood fractions to the full blood remain constant. Preferably, the output signal of the control is proportional to the square root of the full blood flow. The control is preferably formed by a microprocessor.

Method of separating the constituents of the blood

A photoelectric arrangement for the determination of a substance spectrally differently absorbing light in a specimen (1) comprising two alternately switched on light sources (2,3) of different wavelengths matched to the absorption maximum or minimum of the substance, two photoelectric receivers (5,6) arranged in such a manner with respect to the specimen that the one receiver (measuring receiver 5) receives light which traverses the specimen and the other receiver (reference receiver 6) receives light of the light sources directly and an electronic control and evaluation circuit following the photoelectric receivers and controlling the light sources for the determination of the different absorption typical for the substance at the two wavelengths, wherein the control and evaluation circuit comprises a light circuit (7,8,10,11a,11b) following the reference receiver (6) for determining light amounts transmitted by the light sources and defining the switchover instant for the light sources on reaching a predetermined amount of light.

Hemoglobin detector

Multi-lumen tube arrangement for use in a sliding-seal-free centrifuge comprising a plurality of equilength individual tubes (12, 14, 36, 38, 40, 42) which after a twisting about the longitudinal axis of the tube arrangement (10) are each held fixed free of tension at their ends (16-18).

Multi-lumen tube arrangement

The invention relates to a centrifuge arrangement having a centrifuge rotor comprising a drive disc (18) connected to a drive source. Furthermore, the centrifuge rotor comprises at least one separation container (1, 32) which comprises a separation passage (6) and a separation chamber (9) whose outlet and inlet passages lead to the center of the drive disc (18). Advantageously, the separation container (1, 32) is made as self-supporting part of rigid or semi-rigid but flexible material and this makes it possible to insert said container easily into the drive disc (18) and in addition provides advantages in the production of the centrifuge arrangement according to the invention.

Centrifuge arrangement

Failsafe logic circuits, for instance AND-, NOR-, NAND- and OR-circuits are devised at which at least one signal input is connected to a signal output via an optocoupler. Herewith dimensioning problems with respect to transistors and coupling capacitors as known from conventional failsafe logic circuits do not appear. Further on an optocoupler cannot fail in such a manner that between a photodiode and a phototransistor a galvanic coupling may arise.

Failsafe logic circuit wherein the phototransistor of a preceding

Method of separating blood, in particular for recovering thrombocytes and/or leucocytes, the whole blood coming from the donor being separated in a separation means of a centrifuge into an erythrocyte fraction, cell-poor plasma, a thrombocyte fraction and/or possibly a leucocyte fraction, the separated fractions of the blood being discharged via a flexible tubing system of discharge lines out of the separation chambers of the centrifuge and constantly predetermined amounts of separated cell-poor plasma returned to the whole blood to be separated or to the already separated erythrocytes in the separation chamber, and a separation apparatus for carrying out the method comprising a separator having one or more separating chambers connected together and a flexible tubing system which includes a supply line (1, 2) for the supply of the whole blood to be separated to the separator and discharge lines each for the separate discharge of the erythrocyte fraction (10), the cell-poor plasma (3, 5), the thrombocyte fraction (11) and/or possibly leucocyte fractions and a branch line (7) disposed on the output side from the separator in the discharge line (3) for cell-poor plasma for returning cell-poor plasma, the supply and discharge lines and the branch lines (7) of the flexible tubing system being equipped with pumps, and the branch line (7) disposed on the output side of the separator is led off between the separator and the pump (6) and the pump (8, P) diposed in the branch line (7) delivers a predetermined plasma amount.

Method of separating blood and apparatus for carrying out the method

A peristaltically operating roller pump, in particular a hose pump for medical technology, comprises a pump bed (25) whose bearing wall (28) in the exit region (31) has a curvature which is in the same sense as the circular path (33a) of a roller (33) mounted on a pump rotor (1) and which has a radius of curvature which is constant with respect to the circular path (33a) or gradually increases in the direction of rotation of the roller (33). The pump rotor (1) comprises a gear connection so that a constrained radial movement of a roller is converted to a corresponding follow-up movement of the other rollers or roller. By this combination of pump bed and pump rotor pressure peaks and fluctuations of the flow rate are effectively prevented.

Peristaltically operating roller pump and pump rotor therefor

A plurality of scanning regions (22) are disposed about the anticipated region of a phase boundary (32) of two media. The change in position of the phase boundary (32) is detected by a scanning means (18) with which each scanning region (22) is scanned and a signal is generated for each of the scanning regions (22). The first media is more radiation-permeable than the second media. A beam path is generated by the scanning means and is detected and evaluated by a discriminator circuit as a logic one. The second media is less radiation-permeable than the first media. The absence of a beam path corresponding to scanning regions in the second media is evaluated by the discriminator circuit as a logic zero. The number of signals per measuring cycle is compared against the actual number of scanning regions (22) to locate and control the position of the phase boundary (32).

Method and apparatus for the separation of media

A roller pump (1) comprises a stator member (2) in which a pump bed (3) is formed with specific geometry. In the interior of the pump bed (3) a rotor (6) is rotatably mounted. A pump hose (10) can be inserted into the pump bed (3), said hose being curved in loop-like manner and its two ends being combined in immediate vicinity to each other in a connecting piece (11). The connecting piece (11) can be fixed in location in the stator member (2), the arrangement in the stator member (2) being uniquely defined by cooperation of a location tongue (23) and a location slot (22). Interchanging of the pressure-side and suction-side connection is thus impossible. A holding-down member (24) arranged on the rotor (6) permits automatic insertion and ejection of the pump hose (10) or hose system (9).

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St. Wendel, Germany

Hans-Jurgen Neumann