DE102010051996A1 - Producing components by joining ceramic and metallic components, useful e.g. as plate heat exchanger, comprises assembling joining components with component assembly using, and subjecting them to thermal treatment - Google Patents

Abstract

Producing components by joining ceramic components and/or metallic components, comprises assembling the joining components with a component assembly and/or a component using fully fluorinated solid polymers, and subjecting them to a thermal treatment process with a bonding temperature that is greater than the melting temperature of the fully fluorinated solid polymer, a contact pressure that is less than the rupture limit load of the material of the joining components, and with a holding time of less than 1 hour. An independent claim is also included for the component produced by the above method, comprising either component parts made of ceramic material with an arbitrary geometry, which exhibits a disk like- and/or block like structure, where the disks and/or the blocks are joined cohesively by an intermediate layer made of fully fluorinated solid polymers, or component parts made of ceramic-, metallic material and/or plastic, where the materials are cohesively joined using intermediate fully fluorinated polymer that is present in any form.

Description

The invention relates to a method for producing components by joining ceramic components and / or metallic components and a component produced by this method.

In plant engineering and mechanical engineering, components made of ceramic material are used wherever corrosion and high temperatures, but also high purity requirements occur. As a representative of technical ceramics, silicon carbide (chemically named SiC, technically referred to as SSiC in its directly sintered modification) has very good corrosion resistance, very good thermal shock resistance, and high thermal conductivity unlike various metallic materials. Silicon carbide is therefore predestined as a material for the production of heat exchangers in the corrosive as well as in the ultra pure chemical sector.

Basically, two different compounds of SiC components are used in the production of heat exchangers, which are composed of individual plates, connecting parts, etc., on the one hand, the non-positive connection and on the other the cohesive connection.

From the DE 32 00 200 For example, a process is known in which a layer of metal boride is applied to the metal carbide moldings and these are then juxtaposed with their bonding surfaces, pressed together and then heated to form a sintered composite article.

A further development is the in DE 10 2008 019 556 A1 This publication presents a cohesive joining of such heat exchangers and microreactors consisting of thin SiC plates. The plate thicknesses are in the range up to a maximum of 20 mm, but predominantly between 3 to 6 mm. With the cohesive connection of the small SiC plates, a less complex component preparation with respect to parallelism is sought. Suitable adhesives are preferably one-component epoxy and silicone adhesives. The problem with this type of cohesive connection is the uniform application of the adhesive layer, which is why certain viscosity values are specified for this purpose. In addition, these adhesives require relatively long curing times. About the brittleness of the cured joint connection no information is given. The compounds are soluble by burnout (thermal decomposition) of the adhesive at about 500 ° C.

The main drawback of this process, however, is that the types of adhesives incorporated in the claims do not correspond in their chemical resistance to the level of SiC. Thus, components added on this basis have a weak point in chemical resistance lower than that of SiC ceramics.

Furthermore, there are cohesive connections in which the individual SiC components are connected to one another, for example, by diffusion welding.

The DE 10 2004 044 942 A1 describes a method for joining SiC components by diffusion bonding, wherein the components are joined to a monolith in a low-deformation manner. Diffusion-welded monolithic blocks have a high rigidity and a high risk of thermal shock due to possible significant thermal stresses.

From the DE 10 2006 013 503 A1 is a plate heat exchanger, a process for its preparation and its application known. The plate heat exchanger consists of a plurality of plates, preferably of sintered ceramic material, in which fluid flow guide channels are formed as a channel system so that a substantially meandering course of the fluid flow results over the surface of the respective plate, wherein the side walls of the guide channels a plurality of Have breakthroughs that lead to a turbulence of the fluid flow. Furthermore, the invention relates to a method for producing such a plate heat exchanger, in particular a diffusion welding method in which the plates are joined to form a seamless monolithic block.

• – Aufbringen eines polymeren Klebers beispielsweise durch Walzen, Rollen, Rakeln, Spachteln oder Siebdruck auf mindestens eine der Klebeflächen der zu fügenden Platten;
• – Aufeinanderstapeln der zu fügenden Platten;
• – Zusammenpressen der Platten und Fixieren des Plattenstapels;
• – Aushärten des polymeren Klebers unter Beibehaltung der Fixierung in der Weise, daß eine Mindestdicke der Kleberschicht von 25 μm nicht unterschritten wird.

From the DE 10 2008 019 556 A1 is a component of a stack of cohesively bonded plates and a method for its production known. The component is formed from a plurality of stacked plates with fluid flow guide channels, wherein the plates are materially joined by means of a least 25 microns thick adhesive layer of a polymeric adhesive. The associated method comprises the steps

• - Applying a polymeric adhesive, for example by rolling, rolling, knife coating, spatula or screen printing on at least one of the adhesive surfaces of the plates to be joined;
• - Stacking of the plates to be joined;
• - compressing the plates and fixing the plate stack;
• - Curing the polymeric adhesive while maintaining the fixation in such a way that a minimum thickness of the adhesive layer of 25 microns is not exceeded.

This solution has the disadvantage that the adhesive layer thickness can not be applied uniformly or that the adhesive enters the fluid flow guide channels during compression of the plate stack and thereby can form constrictions. Furthermore, dirt particles can accumulate on the exiting adhesive surpluses and thus impair the flow of fluid through the guide channels.

In shell and tube heat exchangers, there is the problem of sealing the tubes made of ceramic material in the tube sheets. Here come to seal on the one stuffing box, for example from the DE 33 10 986 A1 known) or on the other ring seals that are clamped between two tubesheet plates (for example, from DE 197 14 432 A1 known) are used.

The disadvantages are that a large number of glands are needed and the design and the workload are very high. The other solution requires double tubesheets.

Furthermore, in heat exchangers made of ceramic material, the problem of greatly varying material thicknesses, especially in the bottom and / or top parts. This leads to problems in the sintering process. This is where the invention starts.

The object of the invention is to provide a method for producing components by joining ceramic components and / or metallic components and a component produced by this method, with which the disadvantages described above are eliminated.

• – die Fügekomponenten zu Baugruppen und/oder Bauteilen unter Verwendung vollfluorierter fester Polymere zusammengesetzt werden und
• – diese einem thermischen Behandlungsprozeß mit einer Fügetemperatur oberhalb der Schmelztemperatur des vollfluorierten festen Polymers bei einem Anpreßdruck unterhalb der Bruchgrenzbelastung des Materials der Fügekomponenten und einer Haltezeit von weniger als 1 Stunde unterworfen werden.

According to the invention the object is achieved by a method for producing components by joining ceramic components with ceramic, metallic or plastic components with the method steps in that

• - The joining components are assembled into assemblies and / or components using fully fluorinated solid polymers, and
• - These are subjected to a thermal treatment process with a bonding temperature above the melting temperature of the fully fluorinated solid polymer at a contact pressure below the breaking limit load of the material of the joining components and a holding time of less than 1 hour.

The thermal treatment process is carried out by complete or partial introduction of the joining temperature in the joining components, wherein the heating and / or cooling process takes place at spatial temperature gradients of less than 2 degrees / mm. Optionally, the joining components may be provided with a strength enhancing nanosheet of a primer.

The individual joining components are joined by means of a fully fluorinated solid polymer, which is arranged between adjacent components, under pressure and temperature. The fully fluorinated solid polymer as a hot-melt adhesive material can be present as a film, sleeve or in any given geometric shape of the joining problem. Individual components may be partially or completely coated with the fully fluorinated solid polymer. The adhesive strength of the melt-adhesive material is above the maximum pressure load (operating pressure) in the component.

The components of the component made of ceramic material have a disk-shaped, tubular and / or block-like construction in any geometry and the disks, tubes and / or blocks are bonded by means of an intermediate melt-adhesive material made of a fully fluorinated polymer.

There is also the possibility that the components of the component of ceramic and / or metallic material and / or plastic and are joined by means of an intermediate present in any geometric shape fully fluorinated polymer cohesively.

The shape of the fully fluorinated solid polymer is adapted to the geometric shape of the respective ceramic / metallic / plastic components to be joined and may have apertures depending on the structure.

The apertures in the fully fluorinated solid polymer are sized so that outer and inner edges, respectively, are recessed from the edges of the components to be joined, thereby preventing or minimizing entry into the interior of the components upon melting of the material.

The fully fluorinated solid polymer has comparable chemical resistance as the material of the components to be joined.

The component produced by the method may be a tube bundle, plate, block or annular groove heat exchanger or a micro-reactor.

Reference to exemplary embodiments, the invention will be described in detail.

Show it:

1 - Heat exchanger

2 - Head of a heat exchanger

3 - Section of a tube bundle heat exchanger

4 - Section of a tube bundle heat exchanger

The 1 shows as a first embodiment, a schematic representation of a heat exchanger 1 consisting essentially of a headboard 2 a footboard 3 , which are provided with connections for the supply and discharge of the heat-exchanging media, and one between the head and foot 2 ; 3 arranged main part of the blocks 4 is formed with a predetermined channel structure.

In a simple design head and foot consist 2 ; 3 made of metal with an enamelled or otherwise coated surface. The blocks 4 consist for example of a technical ceramics, preferably of SiC.

For making the main part of the heat exchanger 1 become the individual blocks 4 stacked on top of each other, taking between each block 4 each as a fully fluorinated solid polymer, a melt-adhesive film 5 is used. The melt-adhesive foil 5 consists of a fully fluorinated polymer and has a thickness of 0.3 mm. The contour of the melt-adhesive foil 5 is adapted to the contours of the parts to be joined or the melt-adhesive film 5 points according to the channel structure of the blocks 4 Breakthroughs on. Optionally, the surfaces of the items to be joined are provided with a primer.

The so from the individual blocks 4 with the intermediate melt-adhesive foils 5 formed main part of the heat exchanger 1 is clamped, for example, a contact pressure of 2 N / mm ^{2 is} applied to the items to be joined. The prepared main part of the heat exchanger 1 is in a device to a temperature above the melting temperature of the fully fluorinated polymer 5 heated and remains in this after reaching the melting temperature for a period of 2 to 30 minutes, preferably 15 min. Thereafter, the parts are cooled to room temperature. The spatial temperature gradients in the heating and in the cooling process are in the range of less than 2 degrees / mm.

Then this is made up of individual blocks 4 joined body with the head and foot part 2 ; 3 provided, which are braced by means not shown tie rods.

The 2 shows as a further embodiment, a headboard 2 a heat exchanger 1 , which consists of a technical ceramics, preferably of SiC. The headboard 2 consists essentially of the clamping plate 6 , the inlet 7 and the process 8th for the heat exchanging media and the head formed of individual discs.

In heat exchangers made of ceramic material, especially in head and foot parts, the problem of different material thicknesses, which leads to problems in the sintering process.

The headboard according to the invention 2 is made from individual slices 9 formed, whereby the problem of different material thicknesses can be minimized. The individual discs 9 have channels for guiding the heat exchanging media.

The preparation is analogous to the first example. For the production of a headboard 2 of the heat exchanger 1 become the individual slices 9 stacked on top of each other, taking between each slices 9 in each case a melt-adhesive films 5 is used. The melt-adhesive foil 5 consists of a fully fluorinated polymer and has a thickness of 0.3 mm. The contour of the melt-adhesive foil 5 is adapted to the contours of the parts to be joined or the melt-adhesive film 5 points according to the channel structure of the discs 9 Breakthroughs on. Optionally, the surfaces of the items to be joined are provided with a primer.

That's the way from the individual discs 9 with the intermediate melt-adhesive foils 5 formed headboard 2 of the heat exchanger 1 is clamped, for example, a contact pressure of 2 N / mm ^{2 is} applied to the items to be joined. The prepared headboard 2 of the heat exchanger 1 is in a device to a temperature above the melting temperature of the fully fluorinated polymer 5 heated and remains in this after reaching the melting temperature for a period of 2 to 30 minutes, preferably 15 min. Thereafter, the parts are cooled to room temperature. The spatial temperature gradients in the heating and in the cooling process are in the range of less than 2 degrees / mm.

Another embodiment of the invention will be described with reference to a shell and tube heat exchanger. The 3 shows a section of a tube bundle heat exchanger.

In shell and tube heat exchangers, there is the problem of sealing the tubes in the tubesheet. All previous methods for sealing pipes of technical ceramics in the tube sheet are very expensive and coupled to seals.

With the aid of the invention, the problem can be solved in a simple manner. The pipes 10 consist of a technical ceramic, preferably of SiC, and are at their end with a sleeve 12 made of a fully fluorinated polymer. Subsequently, the so prefabricated area of the tube 10 into the hole 13 of the tube bottom 11 pushed.

The tube sheet 11 can be made metallic or ceramic.

Subsequently, this area is heated by means of a heating device. With the help of the heating device, the parts to be joined to a temperature above the melting temperature of the fully fluorinated polymer (sleeve 12 ) are heated and remain in this after reaching the melting temperature for a period of 2 to 30 min, preferably 15 min. Thereafter, the parts are cooled to room temperature. The spatial temperature gradients in the heating and in the cooling process are in the range of less than 2 degrees / mm.

Another embodiment of the invention will be described with reference to a shell and tube heat exchanger. The 4 shows a section of a tube bundle heat exchanger.

The tube sheet 11 is provided with a casing of a fully fluorinated polymer, which includes the holes 13 with included.

The pipes 10 consist of a technical ceramic, preferably SiC, and are the holes 13 of the tube bottom 11 pushed.

Subsequently, this area is heated by means of a heating device. With the help of the heating device, the parts to be joined to a temperature above the melting temperature of the fully fluorinated polymer (casing 14 in the holes 13 ) are heated and remain in this after reaching the melting temperature for a period of 2 to 30 min, preferably 15 min. Thereafter, the parts are cooled to room temperature. The temperature gradients in the heating and in the cooling process are in the range of less than 2 degrees / mm.

This will ensure a secure and tight connection of the pipes 10 with the tubesheet 11 reached. To replace the pipes 10 These are in the area of the bore 13 heated again to the melting temperature of the polymer and can then be removed.

The advantage of the invention is that the joining components of the components and / or assemblies are leak-free, chemically resistant and pressure-tight connected and sealed. The components joined by the method are again detachable, in which the components are reheated and thus separable from each other.

LIST OF REFERENCE NUMBERS

1

heat exchangers

2

headboard

3

footboard

4

block

5

foil

6

chipboard

7

Intake

8th

procedure

9

disc

10

pipe

11

tube sheet

12

shell

13

drilling

14

casing

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3200200 [0004]
• DE 102008019556 A1 [0005, 0010]
• DE 102004044942 A1 [0008]
• DE 102006013503 A1 [0009]
• DE 3310986 A1 [0012]
• DE 19714432 A1 [0012]

Claims (10)

A process for the production of components by joining ceramic components and / or metallic components, characterized in that the joining components are assembled into assemblies and / or components using fully fluorinated solid polymers and this a thermal treatment process with a bonding temperature above the melting temperature of the fully fluorinated solid polymer at be subjected to a contact pressure below the breaking limit load of the material of the joining components and a holding time of less than 1 hour. A method according to claim 1, characterized in that the thermal treatment process is carried out by complete or partial introduction of the joining temperature in the joining components. Process according to Claims 1 and 2, characterized in that the heating and / or cooling process takes place at temperature gradients of less than 2 degrees / mm. A method according to claim 1 to 3, characterized in that optionally the joining components are provided with a strength-increasing nano layer of a bonding agent A component produced by the method according to claims 1 to 4, characterized in that the components of the component made of ceramic material in any geometry have a disc and / or block-like structure and the discs and / or blocks by means of an intermediate layer of a Fully fluorinated solid polymer are joined cohesively. Component produced by the process according to claims 1 to 4, characterized in that the components of the component of ceramic and / or metallic material and / or plastic and are joined by means of an intermediate present in any form, fully fluorinated polymer cohesively. Component according to Claim 5 or 6, characterized in that the fully fluorinated solid polymer is adapted to the respective geometry of the component or is present in any desired form. Component according to claim 5 or 6, characterized in that individual components are partially or completely coated with the fully fluorinated solid polymer. Component according to claim 5 or 6, characterized in that the component is a tube bundle, plate, block or annular groove heat exchanger. Component according to claim 5 or 6, characterized in that the component is a micro-reactor.

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