Heat exchanger tube for a heat exchanger of an oxygenator

Abstract

The invention relates to a heat exchanger tube (1) which is a component of a heat exchanger of an oxygenator. The heat exchanger tube (1) comprises a tube body (2) consisting of thermoplastic polyurethane (PTU). The tube body (2) has a Shore hardness of greater than 60 D. This results in a heat exchanger tube optimised for use in a heat exchanger of an oxygenator.

Claims

1. A heat exchanger tube for a heat exchanger of an oxygenator, comprising a tube body made of a thermoplastic polyurethane (TPU) that is free of gel particles, wherein the tube body (2) has a Shore hardness greater than 60 D, and wherein a wall thickness of the tube body deviates less than 0.02 mm along a length of the tube, and wherein the wall thickness of the tube body is less than 0.07 mm, and wherein the heat exchanger tube has a dielectric strength of at least 10 kV.

2. The heat exchanger tube according to claim 1, wherein the Shore hardness of the tube body (2) is greater than 70 D.

3. The heat exchanger tube according to claim 2, wherein the Shore hardness of the tube body (2) is between 75 D and 83 D.

4. The heat exchanger tube according to claim 1, wherein the tube body comprises amorphous material regions.

5. The heat exchanger tube according to claim 1, wherein the wall thickness of the tube body deviates less than 0.01 mm along the length of the tube.

6. The heat exchanger tube according to claim 1, wherein the wall thickness is between 0.05 mm and 0.06 mm.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The single figure shows a perspective view of a broken section of a heat exchanger tube for a heat exchanger of an oxygenator.

DETAILED DESCRIPTION

(2) A heat exchanger tube 1 is a component of a heat exchanger body (which is otherwise not shown) of a heat exchanger of an oxygenator. The heat exchanger tube 1 can be a component of an oxygenator, as it is otherwise described in WO 2011/086 010 A1, the contents of which are fully incorporated herein in connection with the description of the other oxygenator. The oxygenator has a tubular base body, in which the heat exchanger body is arranged.

(3) The heat exchanger tube has a tube body 2 made of thermoplastic polyurethane (TPU). The tube body 2 has a Shore hardness greater than 60 D. Examples of such a material are Isoplast® 300ETPU with a Shore hardness of 83 D and Tecoplast® TP-470 with a Shore hardness of 82 D.

(4) The thermoplastic polyurethane of the tube body is a polyether-based TPU. The material of the tube body 2 is an aromatic TPU.

(5) The tube body 2 has an inner diameter ID in the range between 0.40 mm and 0.80 mm and a larger outer diameter AD in the range between 0.50 mm and 1.0 mm. With the tube body 2, a wall thickness WD is less than 0.07 mm. Examples of dimensions of the tube body 2 are the following: ID=0.67 mm, AD=0.79 mm, resulting in a wall thickness WD of 0.06 mm, or ID=0.50 mm, AD=0.6 mm, resulting a wall thickness WD of 0.05 mm.

(6) Over a tube length of, for example, 200 mm, the wall thickness WD deviates by less than 0.02 mm from a nominal wall thickness. In fact, the production can be made so precise that the wall thickness WD deviates from a nominal wall thickness by less than 0.02 mm, even over a tube length of more than 1 m, more than 10 m, more than 100 m, more than 1,000 m and also more than 10,000 m.

(7) The heat exchanger tube 1 has an electrical dielectric strength that amounts to at least 10 kV and that is, for example, in the range of 10 kV, 11 kV, 12 kV or 14 kV. To measure the electrical dielectric strength, a wire electrode is introduced into the lumen of the tube body 2, and an outer electrode, in the form of a foil, is brought in contact with an outer wall of the tube body 2. An electrical voltage is then applied to the two electrodes and continuously increased until a breakdown occurs. This measurement of dielectric strength is carried out in accordance with DIN EN 60243-1. A value of 14 kV for the dielectric strength can be achieved with a larger wall thickness WD, for example, 0.06 mm. A value of 10 kV for the dielectric strength can be achieved with a smaller value of the wall thickness WD, for example, 0.05 mm. With a wall thickness WD in the range of 0.065 mm, a dielectric strength of 12 kV was measured in a series of measurements. With a wall thickness WD of 0.06 mm, a dielectric strength of 10 kV was measured in the series of measurements. With higher wall thicknesses WD, for example 0.077 mm, a dielectric strength of 11 kV was measured in the series of measurements. For an additional composition of the tube body 2, with a wall thickness WD in the range of 0.075 to 0.085 mm, a dielectric strength of up to 14 kV was measured in the series of measurements.

(8) The tube body 2 is transparent to visible light. The tube body 2 is essentially free of inclusions.

(9) In the production of the tube body 2, a TPU plastic melt is first produced.

(10) This plastic melt is then filtered. The filtration is used in particular for filtering out gel particles contained in the melt.

(11) The filtered melt is then extruded into a tube. The extruded tube is cooled. This takes place by running the extruded tube through a tempering chamber containing a heat transfer medium, for example, by passing the extruded tube through a water basin, wherein the water is maintained at a temperature in the range between 5° and 15°, for example at a temperature of 10°.

(12) Such cooling of the material produces amorphous material regions in the tube body 2.

(13) After cooling, the tube thus produced is assembled into tube sections required for the construction of the heat exchanger body, and the tube sections are then mounted on the heat exchanger body and on the heat exchanger. The heat exchanger is the main component of the oxygenator. In this connection, reference is made to WO 2011/086 010 A1.