DE102007056169A1 - Cylindrical heating element for e.g. medical hose for tempering blood in medical fluid line, has heating wire arranged helically around flexible interior material, and core material arranged in radial distance to heating wire - Google Patents

Abstract

The element (1) has a heating wire (4) arranged helically around a flexible interior material. A core material running coaxially in a center is arranged in a radial distance (A) to the heating wire. The core material is made of a threadlike plastic material or a fiber composite material such as aramide material. The heating wire is surrounded by a flexible isolation element (9), where the heating element has a concentric braid design with multiple braids surrounding an outer circumferential surface of the flexible interior material. An independent claim is also included for a device for tempering fluid led in a medical fluid line.

Description

The The invention relates to a heating element for a device for tempering a guided in a medical fluid line Fluids with at least one heating wire.

Further the invention relates to a device for controlling a temperature in a medical fluid line guided fluid.

From the EP 1 066 844 B1 a device is known for controlling the temperature of an intravenous fluid which is guided in a medical fluid line (medical tube). The medical tube, for example, serves to deliver an intravenous fluid, such as blood or saline, to a patient. In order for the intravenous fluid to reach the patient at a temperature in a temperature range of 37 ° to 38 ° C, a heating element is integrated in the tube. The heating element is designed as a heating wire and extruded with a diametrically extending in the cavity of the hose web. The bridge is - as the surrounding the cavity of the hose - flexible. The web may for example be formed of an elastomeric material.

From the EP 1 747 790 B1 a device for tempering a guided in a medical fluid line fluid is known, in which a heating element is arranged integrated in a surrounding the fluid line sheath line. The medical fluid line may be formed as an infusion tube. The heating element is designed as a heating wire, which can be produced together with the sheathed cable by extrusion. The sheathed cable is made of a flexible plastic material and has a longitudinal slot, so that the infusion tube can be used under the circumferential environment of the same by the sheathed cable in this.

The resulting from the sheath line and the infusion tube resulting structure is exposed to a continuous bend, with the heating wire partially stretched or compressed. This mechanical stress can sometimes lead to breakage of the heating wire, so that the fluid does not heat to the required extent becomes.

task The present invention is therefore a heating element and a Device for tempering a in a medical fluid line developed fluid such that the breaking strength of the heating element improved and thus a long-term stable and reliable use of the heating element allows becomes.

to Solution to this problem is the heating element in conjunction characterized by the preamble of claim 1 characterized that the heating wire helically around a flexible inner material is arranged.

Of the particular advantage of the invention is that by helical Arrangement of a heating element arranged around a flexible material Breaking strength of the heating element can be significantly improved. The flexible inner material serves as a carrier and causes that no undesirable notch effect occurs, which leads to a Breakage of the heating element could result. The heating element is configured such that it incorporates the heating element in a plastic material of a medical tube at Resists occurring bending and tensile forces.

To a preferred embodiment of the invention is in Center of the flexible inner material a tensile core core arranged as a tension stabilizer for winding the at least one helical Heating wire on the flexible inner material is used. While the elasticity of the flexible inner material at least is approximately isotropic, the core is only in the transverse direction highly elastic and relatively long in the longitudinal direction and not plastically deformable.

To a preferred embodiment of the invention is that flexible inner material made of an elastomeric material, in particular formed of a silicone (rubber) material.

To a preferred embodiment of the invention is the Core core of a thread-like plastic material or a fiber composite material, especially aramid, formed.

To a preferred embodiment, the heating element a concentric Litzengestaltung on with a plurality of helical an outer Peripheral surface of the flexible inner material surrounding strands. By dividing the given cross-section for the heating element in a plurality of a respective relatively small Cross-section strands can breakage of the heating element be further reduced.

To a development of the invention is the quotient of the diameter the outer peripheral surface of the flexible Inner material and larger from the diameter of the strands than five. Advantageously, this ensures that that the strands have a sufficiently high radius of curvature and thus the risk of breakage of the same is reduced.

To achieve the object, the device according to the invention in conjunction with the preamble of claim 15, characterized in that the heating element is surrounded by a flexible insulating element.

Of the particular advantage of the device according to the invention is that a heatable medical hose is formed with a long life. This is achieved by the integration of a relatively break-resistant heating element.

To a development of the invention is that at least from the heating wire and the flexible inner material forming te heating element in a polymer core a flexible medical tube integrated. From the peripheral surface of the polymer core extends at least a web to a jacket of the hose, being between the polymer core and the sheath a cavity is formed for guiding the Fluid. The heating element is advantageous in the region of a central axis arranged the hose, so that acting on the heating element mechanical forces under bending stress relatively low are. Advantageously, thereby the life and effectiveness the tube with respect to the temperature of the fluid improved become.

To a development of the invention is that of the heating wire and The heating element formed in the flexible inner material in a sheathed cable arranged integrally, which has a longitudinal slot for Admission of a flexible medical tube. Advantageously Here, the result of the off-center arrangement of the heating element increased bending stress counteracted.

To a development of the invention is the flexible inner material formed as a tube, the inside over at least a web with a polymer core and on the outside of the Heating wire and / or the insulating element is surrounded. Advantageous Here, a medical tube can be made in which to one formed the heating element relatively unbreakable and the other an improved heat transfer to the fluid guaranteed. Since preferably the heating wire over the entire surface arranged on a peripheral surface of the flexible inner material is, the flexible tube is fully heated circumferentially, the heat being inward in the radial direction a relatively large area can be radiated.

To a development of the invention, the heating wire on the flexible Inner material in the plastic state of the same wound helically, that the heating wire remains fixed in this winding position. The Fixation is effected in particular by the fact that the spiral wound heating wire in spiral grooves of the cylindrical Inner material is embedded, allowing a shifting of the loops of the heating wire is not possible.

Preferably can after winding the heating wire on the cylindrical Inner material by extrusion an outer insulating element be applied, which is a homogeneous connection with the cylindrical flexible inner material enters, with the heating wire between the flexible inner material and the outer insulation element is held firmly. For example, the device may be medical Hose or as a flat hose warmer be educated.

Further Advantages of the invention will become apparent from the other dependent claims.

embodiments The invention will be described in more detail below with reference to the drawings explained.

It demonstrate:

1 a side view of a cylindrical heating element,

2 a cross section through the heating element according to 1 .

3 a cross section through a heating element according to a further embodiment,

4 a cross section through a surrounding a infusion hose sheathed cable in which a heating element is integrated,

5 a cross-section through an infusion tube with a polymer core, in which a heating element is integrated and arranged

6 a perspective view of an infusion tube with a tubular flexible inner material, on which at least one heating wire is wound helically.

A device for tempering a fluid guided in a medical fluid line consists essentially of a heating element 1 , which according to a first embodiment of the invention according to the 1 and 2 essentially of a flexible inner material 2 and at least one helically around an outer peripheral surface 3 of the inner material 2 laid heating wire 4 (Heating conductor).

The flexible interior material 2 is cylindrical and made of an elastomeric material, in particular of a silicone (rubber) material.

Preferably, a plurality of heaters wires 4 one or more layers on the outer peripheral surface 3 of the flexible interior material 2 arranged. For example, four heating wires 4 or strands to form an axial distance A to each other helically on the flexible inner material 2 be arranged. Due to the axial distance A of the heating wires 4 an undesirable short circuit of the same is prevented. The outer peripheral surface 3 of the flexible interior material 2 is only partially from the four heating wires 4 covered.

In the multi-layered embodiment, the outer peripheral surface 3 of the flexible interior material 2 of several layers in the same or opposite direction and insulated heating wires 4 or strands are covered.

The four heating wires 4 are preferably in the form of a concentric Litzengestaltung, wherein the individual strands are arranged helically and coaxially with each other. The ends of the heating wires 4 or the strands are the end of the heating element 1 electrically connected to each other. How out 2 can be seen, is a diameter d _{I of} the inner material 2 more than five times the diameter d _{H of} the heating wires 4 or the strands.

For the production of the heating element 1 In a first step, the cylindrical inner material 2 extruded. In the plasticized state of the inner material 2 then becomes the interior material 2 from the heating wire 4 under the same on the outer peripheral surface 3 wrapped.

According to a first embodiment, the outer peripheral surface 3 completely from the heating wire 4 or a plurality of heating wires 4 be surrounded. According to a second embodiment, the peripheral surface 3 of the inner material 2 from a heating wire 4 be wrapped, wherein a portion of the peripheral surface 3 is not covered. Preferably, this is the wrapping of the heating wire 4 forming a constriction, leaving the heating wire 4 in a spiral groove of the cylindrical inner material 2 is arranged. The not of the heating wire 4 Covered portion of the peripheral surface 3 can be used for (homogeneous) connection with a plastic material, for example a hose, wherein the heating wire 4 firmly fixed in its insertion position. The heating wire 4 is thus together with the cylindrical inner material 2 and the further outer plastic material extruded together. Alternatively, the heating wire 4 also be wound up so that it is on the peripheral surface 3 rests.

For example, the heating wire 4 Even after an embodiment of the invention, not shown, flush with the surface of the free area of the peripheral surface 3 of the inner material 2 is arranged.

After completion of the heating element 1 This can for example in one with a longitudinal slot 5 provided sheathed cable 6 according to 4 be integrated so that one over the longitudinal slot 5 in a central cavity of the sheathed cable 6 inserted flexible medical hose 7 or in the hose 7 existing fluid is heated. The sheathed cable 6 can in the EP 1 747 790 B1 having shown construction with a number of heating elements 1 , which in continuous cylindrical passages of the sheath line 6 used or by extrusion with the sheathed cable 6 are connected. In addition, the sheathed cable 6 a temperature sensor at the end 8th have, so that in connection with a control unit, the heating element 1 is so charged with electric current, that in the hose 7 located fluid is heated to a predetermined temperature. If the fluid is blood, the heating element becomes 1 subjected to such an electric current, that to the hose 7 transferred heat energy sufficient to maintain the predetermined temperature regime of the fluid.

According to the first embodiment, the heating element 1 exclusively from the cylindrical inner material 2 and the helical on the peripheral surface 3 the same applied heating wire 4 , The heating element 1 is thus not insulated on the outside and can serve, for example, as an electrode for the electrical connection of a heating conductor integrated in a medical tube.

According to a further embodiment of the invention according to the 1 and 2 is the at least one heating wire 4 from a flexible insulation element 9 completely surrounded. Preferably, a heating wire 4 with four strands around the cylindrically shaped flexible inner material 2 wound. The cylindrical inner material is designed as a solid cylinder. The strands of the heating wire 4 or the heating wire 4 is enclosed in corresponding helical (spiral) annular grooves of the flexible inner material. By this constriction or embedding in the spiral grooves is a tight fit of the heating wire 4 ensures that slipping in the longitudinal direction of the individual loops of the heating wire is not possible. By extruding with a flexible inner material 2 and the heating wire used 4 surrounding flexible insulation material 9 (Insulation jacket) is a homogeneous connection between the cylindrical inner material 2 and the insulation jacket 9 including the spirally arranged heating wire 4 created.

Preferably, the flexible Isolationsele ment 9 as an elastomeric material (silicone (rubber) material) which forms the heating wires 4 (Heating layer) circumferentially completely covers. In the in 4 illustrated embodiment of the heating element 1 is such an isolation element 9 (Insulation layer) not required because the insulating effect of the sheathed cable 6 itself is taken over.

According to a further embodiment of the invention according to 3 may be a central core material compared to the previously described embodiments 10 in a flexible inner material 2 ' a heating element 1' be embedded. The flexible interior material 2 ' is thus formed as a hollow cylinder. The central nuclear material 10 has different mechanical properties than the flexible inner material. In particular, the core material 10 be formed as a tensile core core, which consists of a thread-like plastic material or a fiber composite material, in particular aramid, or glass fibers as the core cylinder. For example, the core cylinder 10 also be formed from an aramid material or the like. It is essential that the core cylinder 10 in the longitudinal direction has a relatively high strength, while it is flexible in the transverse direction, that is designed to be resistant to bending. The tensile core soul 10 serves to train stabilization when helically winding the heating wires 4 on the outer peripheral surface 3 of the inner material 2 ' ,

According to an embodiment of the invention, not shown, the in 3 illustrated heating element 1' even without the outer insulation layer 9 be educated.

Same Components or component functions of the embodiments are provided with the same reference numerals.

The flexible interior material 2 ' is thus tubular, wherein it has such an outer diameter d _I that the at least helically wound heating wire 4 shatterproof is stored. To the heating wire layer 4 can - as in the embodiment of the 1 and 2 - the insulation layer 9 connect.

The heating elements described above 1 . 1' For example, in a medical tube 11 according to 5 be arranged integrated. The medical tube 11 For example, it may be formed as an infusion tube in which blood or saline solution is transported as fluid. For this purpose, the medical tube 11 a polymer core 12 of a PVC material and a flexible outer tube disposed at a radial distance therefrom 13 made of a PVC material, with the outer tube 13 by means distributed in the circumferential direction webs arranged 14 spaced from the polymer core 12 is arranged. In the space between the polymer core 12 and the outer tube 13 an annular channel is formed, through which the fluid can flow. For temperature control or heating of the fluid is in an axial central region of the polymer core 12 the heating element 1 . 1' arranged. In addition, in the polymer core 12 be arranged at least one temperature sensor. The bridges 14 may be made of a PVC material and are preferably integral with the polymer core 12 and the flexible outer tube 13 connected. Preferably, the heating elements 1 . 1' together with the polymer core 12 extruded.

According to a further embodiment of the invention according to the 6 is a medical tube 16 provided, on the one hand a polymer core 17 made of PVC material and spaced from the polymer core 17 trained outer tube 18 having. The outer tube 18 is - as in the embodiment according to 5 - Distributed in the circumferential direction arranged webs 19 integral with the polymer core 17 connected. In contrast to the previous embodiment is in the outer tube 18 arranged the heating element integrated. The outer tube 18 is on the one hand by an annular flexible inner material 20 (Inner layer), one on the outer peripheral surface of the inner material 20 subsequent and from at least one heating wire 4 formed heating layer 21 and an outer flexible insulation element 22 (Insulation layer) formed. In contrast to the previous embodiments, here is a tubular flexible inner material 20 provided, in one piece with the webs 19 connected is. Depending on the number and preferably helical distribution of the heating wires 4 on a peripheral surface 23 of the flexible interior material 20 is the same au ßenseitig either completely from the heating wires 4 or from the heating wires and the insulation layer 22 surround. The flexible interior material 20 consists of the same material as the inner material described in the previous embodiments 2 . 2 ' ,

Advantageous the invention allows for infusion heating used in medical / laboratory technology. As infusions can Blood, blood substitutes, plasma substitutes or electrolyte solutions serve.

According to one embodiment of the invention, the sheathed cable 6 or the flexible isolation element 9 . 20 or the interior material 2 . 2 ' or insulation layer 22 of a thermally conductive polymer material, in particular of a thermally conductive silicone (rubber) material exist.

It is understood that the above described NEN medical hoses represent exemplary applications for the use of the heating element according to the invention. The invention is not limited to cylindrical devices. For example, the device may also be plate-shaped, wherein a plurality of heating elements spaced from one another in a surface are arranged. For example, the device may be designed as a plate warmer.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1066844 B1 [0003]
• - EP 1747790 B1 [0004, 0038]

Claims (20)

Heating element for a device for tempering a fluid guided in a medical fluid line with at least one heating wire, characterized in that the heating wire ( 4 ) helically around a flexible inner material ( 2 . 2 ' . 20 ) is arranged. Heating element according to claim 1, characterized in that at a radial distance from the heating wire ( 4 ) a core material running coaxially in the center ( 10 ) is arranged. Heating element according to claim 1 or 2, characterized in that the core material ( 10 ) is formed as a tensile core core. Heating element according to claim 3, characterized in that that the core core is formed as a flexible core cylinder. Heating element according to one of claims 1 to 3, characterized in that the core material of a thread-like Plastic material or a fiber composite material, in particular Aramid material is formed. Heating element according to one of claims 1 to 5, characterized in that the tensile core material ( 10 ) completely from the flexible inner material ( 2 . 2 ' ) is sheathed. Heating element according to one of claims 1 to 6, characterized in that the flexible inner material ( 2 . 2 ' ) is formed as an elastomer material, in particular as a silicone (rubber) material. Heating element according to one of claims 1 to 7, characterized in that the heating element ( 1 . 1' . 21 ) has a concentric strand configuration with a plurality of helically an outer peripheral surface ( 3 ) of the flexible inner material ( 2 . 2 ' ) surrounding strands. Heating element according to one of claims 1 to 8, characterized in that the quotient of the diameter (d _I ) of the outer peripheral surface ( 3 ) of the flexible inner material ( 2 . 2 ' ) and the diameter (d _H ) of the strand and / or the heating wire ( 4 ) is greater than five. Heating element according to one of claims 1 to 9, characterized in that the strands and / or the heating wire ( 4 ) in the plastic state of the outer peripheral surface ( 3 ) of the flexible inner material ( 2 . 2 ' . 20 ) are arranged on the same laid out. Heating element according to one of claims 1 to 10, characterized in that the outer peripheral surface ( 3 ) of the flexible inner material ( 2 . 2 ' . 20 ) not completely from the at least one heating wire ( 4 ) or the strands is covered. Heating element according to one of claims 1 to 11, characterized in that the outer peripheral surface ( 2 . 2 ' ) of the flexible inner material ( 2 . 2 ' . 20 ) of a plurality of layers of insulated heating wires ( 4 ) or strands is covered. Heating element according to one of claims 1 to 12, characterized in that the at least one heating wire ( 4 ) of a flexible insulation element ( 9 ) is surrounded. Heating element according to one of claims 1 to 13, characterized in that the flexible insulation element ( 9 ) is formed of an elastomeric material. Device for tempering a fluid carried in a medical fluid line with a heating element extending along the fluid line according to one of claims 1 to 14, wherein the heating element ( 1 . 1' ) of a flexible insulation element ( 9 ) is surrounded. Apparatus according to claim 15, characterized in that the from the flexible inner material ( 2 . 2 ' ) and the at least one heating wire ( 4 ) formed heating element ( 1 . 1' ) in a polymer core ( 12 ) of a flexible medical tube ( 11 ) for heating one in the hose ( 11 ) guided intravenous fluid is arranged integrated. Device according to claim 15 or 16, characterized in that the polymer core ( 12 ) on the outside via at least one web ( 14 ) with a flexible outer tube ( 13 ) is connected to form an annular space for the passage of the fluid. Apparatus according to claim 15, characterized in that the from the flexible inner material ( 2 . 2 ' ) and the at least one heating wire ( 4 ) formed heating element ( 1 . 1' ) in one with a longitudinal slot ( 5 ) and a flexible medical tube ( 7 ) receiving sheathed cable ( 6 ) is arranged integrated. Device according to claim 15, characterized in that the flexible inner material ( 20 ) is formed as a tube, the inside on at least one web ( 19 ) with a polymer core ( 17 ) and the outside of the at least one heating wire ( 4 ) and / or the insulation element ( 22 ) is surrounded. Device according to one of claims 15 to 19, characterized in that the heating wire ( 4 ) in the plastic state on the outer peripheral surface ( 3 ) of the flexible inner material ( 2 . 2 ' . 20 ) is wound such that in the fluid line between the loops of the heating wire ( 4 ) raised flexible inner material ( 2 . 2 ' . 20 ) with a flexible insulation element ( 9 ) in the longitudinal direction of the hose ( 11 ) forms a compound when extruding it.