E.i. Dupont De Nemours and Company

Dupont Canada Inc.

Robert P Luoma, Ii

Frank M Willis

George A Adams

Joshua Benin

Helen E Roxlo

A method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities, a separation device and a tube containing the separation device. The sample of liquid is placed in a first chamber of a linear tube that is separated from a second chamber by a separation device. The separation device slidably engages the interior surface of the tube in an essentially fluid-tight manner and has an axial orifice on the longitudinal axis of the tube that is in fluid flow communication with a flow-restriction channel. The phases are ordered concentrically by rotating the tube around its longitudinal axis e.g. in an axial centrifuge. The volume of the first chamber is reduced by movement of the separation device within the tube, that phase of the liquid located axially within the first chamber flowing into the axial orifice and passing through the flow-restriction channel into the second chamber. The reduction of the volume of the first chamber is controlled using phase-separation information. The method is useful in separation of blood components.

Flow restrictor-separation device

A tube and method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities. The tube has a smaller diameter at one end. In use, a sample of liquid is passed through a first end of a linear tube and into a first chamber of said tube. The first chamber is located at the first end of the tube and is separated from a second chamber located at a second opposed end of the tube by a separation device. The separation device slidably engages the interior surface of the tube in an essentially fluid-tight manner and has a flow-restriction orifice therein to permit fluid flow communication between the first and second chambers under the influence of force. The phases are then ordered within the tube using e.g. axial centrifugation. The volume of the first chamber is reduced by movement of the separation device within the tube, such that one phase of the liquid in the first chamber flows through the flow-restriction orifice and into the second chamber. The method is monitored using the section of the tube that has the smaller diameter.

Phase-separation tube

A method of partitioning a pre-selected phase of a sample of liquid having a plurality of phases of differing densities, and a tube. A sample of liquid is passed through a first end of a linear tube and into a first chamber of said tube. The first chamber is located at the first end of the tube and is separated from a second chamber located at a second opposed end of the tube by a separation device. The separation device slidably engages the interior surface of the tube in an essentially fluid-tight manner and has a flow-restriction orifice therein to permit fluid flow communication between the first and second chambers under the influence of force. The phases are then ordered within the tube using e.g. axial centrifugation. The volume of the first chamber is reduced by movement of the separation device within the tube, such that one phase of the liquid in the first chamber flows through the flow-restriction orifice and into the second chamber.

Centrifugal methods using a phase-separation tube

A plasmapheresis filtration module having stacked grooved plates interleaved with membranes, enclosed in a unitary, flexible, impermeable envelope, sealing being effected by pressing the membranes between blood flow channels and a sealing surface on a plasma side support.

Plasmapheresis filtration module having pressure balancing and sealing

Plasmapheresis filtration module having improved sealing means

An electric heating element for sterilely cutting and welding together a pair of thermoplastic tubes transversely of the axis of each tube includes as an outer layer a folded sheet of a metal, such as copper, aluminum, silver or gold, having a thermal conductivity of at least about 173 watts/m.degree.K at a thickness of 0.10 mm and a tensile yield strength of at least 34.times.104 kPa at a 0.10 mm thickness. A resistance heating element, preferably having a positive thermal coefficient of resistance (PTC), in the form of a resistor of stainless steel or the like is disposed inside the fold of the metal sheet and a layer of dielectric adhesive, such as an epoxy or acrylic adhesive, stable to about 260.degree. C., is disposed between the inner surfaces of the metal sheet and the resistor to insulate the resistor from the folded sheet and bond the resulting structure together. The folded edge of the metal sheet forms the melting edge of the heating element. The heating element has a thickness of from about 0.13 mm. to about 0.76 mm.

Electric heating element for sterilely cutting and welding together

There is disclosed a method of monitoring the temperature of a cutting element in a sterile docking apparatus for splicing two sterile thermoplastic tubes together by using a resistor-heated cutting means, the method comprises (1) supplying a constant current to the resistor; (2) measuring the initial voltage of the resistor; (3) calculating, according to predetermined empirical relationship(s), the voltage, time or both required to achieve a desired cutting means temperature if the initial voltage is within a suitable range, (4) measuring repeatedly the voltage of the resistor and the time to determine whether (a) the voltage reaches the calculated voltage within a specified time frame or (b) the calculated time has been reached within a specified voltage range and (5) splicing the tubes with the cutting means if the time frame or voltage range is met. The method is also applicable to other resistor-heated elements in other devices having a constant heat load environment.

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Newark, DE, United States of America

Robert P Luoma, Ii