HIGH-PERFORMANCE FLOW HEATER

Abstract

A flow heater (100, 200, 300, 400, 500, 600, 700, 800) with a metal section (101, 201, 301, 401, 501, 601, 701, 801), with at least one tube (103, 104, 203, 204, 303, 304, 403, 503, 603, 604, 705, 706, 707, 708, 709, 710, 805, 806, 807, 808, 809, 810) for passing through a fluid to be heated is mounted and preferably pressed, at least in some sections, into the metal section (101, 201, 301, 401, 501, 601, 701, 801). At least one tubular heating body (102, 202, 209, 210, 302, 402, 409, 410, 502, 602, 702, 703, 704) that is arranged outside the tube interior space, is mounted in and preferably pressed into, the metal section (101, 201, 301, 401, 501, 601, 701, 801) at least in some sections. The at least one tubular heating body (102, 202, 302, 402, 502, 602, 702, 802) is surrounded by the one tube or by a plurality of the tubes (103, 104, 203, 204, 303, 304, 403, 503, 603, 604, 705, 706, 707, 708, 709, 710, 805, 806, 807, 808, 809, 810) for passing through a fluid to be heated. A process for manufacturing such a flow heater is also provided.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. §119 of German Utility Model DE 20 2010 006 739.1 filed May 12, 2010 and German Patent Application DE 10 2011 012 770.4 filed Mar. 1, 2011, the entire contents of each of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention pertains to a flow heater with a metal section, with at least one tube for passing through fluid to be heated, which is mounted in and preferably pressed into the metal section at least in some sections, and with at least one tubular heating body, which is arranged outside the tube interior space and is mounted in and preferably pressed into the metal section at least in some sections.

BACKGROUND OF THE INVENTION

Such flow heaters are used to heat fluids (i.e., especially liquids and/or gases) and are used, for example, in dishwashers, steam cookers or washing machines and are known, for example, from DE 42 26 325 C1.

Prior-art flow heaters usually have a metal section, in which a tube for passing through a fluid to be heated is mounted. One or more adjacent tubular heating bodies, which are likewise mounted in the metal section, are arranged around the tube outside the tube interior space thereof. To guarantee a direct and close contact between the metal section and tubular heating body, on the one hand, and the metal section and tube for passing through a fluid to be heated, on the other hand, the arrangement is usually fully or partly compressed.

The requirement on the performance of such flow heaters has noticeably increased over the last few years. It was found that the flow heaters of conventional design, as they are known from the state of the art, reach their limits with the use of tubular heating bodies of ever-increasing performance, because sufficient heat transfer into the fluid is no longer guaranteed. This leads to an unacceptably high temperature on the outside of the flow heater and in the extreme case to melting of the metal section.

In a second type of flow heaters, which are known, e.g., from DE 10 2005 036 816 A1, a tubular heating body is arranged in the interior of a tube for passing through a fluid to be heated. Thus, it is in direct contact with the fluid, which significantly increases the risk of failure of the tubular heating body as a consequence of the interaction thereof with the fluid, because local deposits, for example, calcifications, which hinder the dissipation of heat and lead to destruction of the tubular heating body, occur in the systems used in practice in a number of applications. If corrosive media are heated, the direct contact with the fluid may likewise damage the tubular heating body. In addition, especially if they are used with high surface loads and low flow velocities, such flow heaters may cause bubbling in liquids to be heated, which will likewise lead to a local hindrance of the dissipation of heat and entail the risk of destruction.

SUMMARY OF THE INVENTION

The object of the present invention is consequently to provide a high-performance but nevertheless compact flow heater, which can be used in situations with limited availability of space and whose outer temperature remains limited and which ensures good heat transfer to the fluid, while the tubular heating body is at the same time protected from the fluid.

According to the invention, a flow heater is provided with a metal section, with at least one tube for passing through fluid to be heated, which is mounted in and preferably pressed into the metal section at least in some sections, and with at least one tubular heating body. The tubular heating body is arranged outside the tube interior space and is mounted in and preferably pressed into the metal section at least in some sections. The tubular heating body is surrounded at least in some sections by one or more of the tubes for passing through a fluid to be heated.

The flow heater according to the present invention has a metal section, with at least one tube for passing through a fluid to be heated or a plurality of fluids to be heated, which is mounted, at least in some sections, in the metal section and is preferably pressed in, and at least one, preferably pressed-in tubular heating body, which is arranged outside the tube interior space and is mounted at least in some sections in the metal section. Consequently, the tube extends adjacent to the tubular heating body, which does not absolutely require a direct contact, but it does express the fact that the tube extends separately from the tubular heating body but does so in the vicinity thereof or directly adjoining same.

The term “tubular heating body” is to be defined very broadly in the context of this patent specification; in embodying the present invention, it is possible to use as the tubular heating body, in principle, any heating element with a metal (outer) jacket, i.e., even a heating cartridge, a flat heating element or a hollow cartridge.

It is essential for the present invention that at least one tubular heating body is surrounded by a tube arrangement of at least one tube or a plurality of the tubes for passing through fluid (a fluid or fluids) to be heated at least in some sections, so that it is ensured that the heat released by the tubular heating body is released mostly into the fluid to be heated.

Consequently, an essential idea of the present invention is to abandon the current design principle, in which it was important to maximize the introduction of heat into the fluid by providing a tube surrounded by a tubular heating body (arranged, e.g., in a coiled or meandering pattern around the tube) or by a plurality of tubular heating bodies for passing through a fluid to be heated, utilizing the larger outer surface of the tube for passing through a fluid to be heated. This design principle abandonment is based on the discovery that the provision of one or more tubes for passing through the fluid to be heated, which surrounds/surround the tubular heating body or tubular heating bodies, effectively utilizes the capacity of the tubular heating body and hereby prevents excessive heating of the outer surface of the metal section along with a simultaneous good heating capacity.

It is pointed out for clarification that the terms “surround” and “enclose” are to be clearly distinguished within the framework of the present invention. “Surround” means that when viewed at right angles to the direction in which the surrounded tubular heating body extends, sections of one or more tubes for passing through a fluid to be heated are arranged in a plurality of directions, which especially also form angles exceeding 90° relative to one another. Only the term “surround” is used in the sense that when viewed at right angles to the direction in which the surrounded tubular heating body extends, sections of one or more tubes for passing through a fluid to be heated are arranged in all directions.

In an advantageous embodiment of the present invention, the metal section is a hollow section or it forms a component of a composite hollow section. A hollow section is present if a hollow space is defined by the metal section, optionally in conjunction with additional wall sections, which may be formed, for example, by wall sections of a tube for passing through a fluid to be heated. A hollow section may be, in principle, open or closed. An example of an open hollow section is a tube; if the openings of the tube are closed with covers, an example of a closed hollow section is obtained.

The tubular heating body and the tube arrangement with the at least one tube for passing through a fluid to be heated are arranged and preferably pressed in at least in some sections in the hollow section, i.e., in the interior of the hollow space, together with a sealing compound or with a powder or granular material, in which the heater, the at least one tube for passing through a fluid to be heated or the heater and the at least one tube for passing through a fluid to be heated are embedded at least partly.

By providing a hollow section, in which the heater and/or the at least one tube for passing through a fluid to be heated are arranged together with a powder or granular material, in which the heater and the at least one tube for passing through a fluid to be heated are embedded at least partly, and are preferably pressed in at least in some sections, it becomes unnecessary to prepare grooves or holes in the metal section, because the thermal contact is established via the powder or granular material, which not only saves costs and ensures a more reliable thermal contact, but also permits a more flexible shaping of the heater and tubes, because the sealing compound or the powder or granular material can be filled in later. It becomes possible, for example, to use tubes or heaters with a one-sided connection, which makes possible a more compact installation.

An especially simple and cost-effective flow heater is obtained if the hollow section comprises two metal sections connected to one another. This makes it possible to simply provide a metal section as a bottom, to insert the heater and tubes in said bottom and then to attach another metal section as a cover, which is then connected to the bottom, for example, by soldering or welding. If the cover and bottom form an open hollow section, the “profiled tube” formed may be filled with powder or a granular material, e.g., in a forging die, optionally compacted and optionally provided with front-side closing surfaces. A closed hollow section is formed if the cover and/or bottom have side walls each, which define a closed space in the connected state when the heater and tubes are inserted, and the powder or granular material must be inserted in this case before the cover and bottom are connected to one another.

An especially compact design of the flow heater is obtained by the hollow section being composite and by at least one section of the wall of the at least one tube for passing through a fluid to be heated forming, besides the at least one metal section, a component of the composite hollow section, because this avoids a complete “building around” the tubes. Especially simple here is a design in which at least two tubes for passing through a fluid to be heated are present and the hollow section is formed from sections of the walls of the tubes for passing through a fluid to be heated and metal sections, which connect these sections of the wall of the tubes. The simplest design thus formed would be an open hollow section, i.e., one formed from a cover formed by a metal section and a bottom formed by a metal section.

It is especially preferred because of this good heat conduction that can thus be achieved if the powder or granular material consists of metal, especially aluminum, copper, brass or a mixture thereof.

In an advantageous embodiment, at least one tube for passing through a fluid to be heated is directly in contact at least in some sections with the heater in the form of the tubular heating body, which makes possible an especially direct heat transport. In particular, a tube can extend, led around a tubular heating body, such that the tube surrounds the tubular heating body on all sides, for example, if a tube coiled around the tubular heating body is used.

Another advantageous embodiment of the flow heater is characterized in that the metal section consists of a material that has a poorer thermal conductivity than the powder or granular material. As a result, the temperature prevailing on the surface of the flow heater at a given power consumption of the flow heater can be markedly reduced at equal outside dimensions compared to prior-art flow heaters, in which the heat transport takes place from the heater to the tube via the metal section, which must therefore be manufactured from a material with good thermal conductivity, and the use of metal sections with poor conductivity, e.g., those made of Cr—Ni steel, is made possible. In addition, the material costs for the metal sections can thus be reduced.

A control and/or regulating element is advantageously provided at the flow heater. Manufacturing losses are avoided in case of pressure-sensitive control and/or regulating elements if the control and/or regulating element is arranged on the outside of the metal section. Embedding of the control and/or regulating element in the powder or granular material makes regulation possible on the basis of data that are detected with very high accuracy close to the site of heat transfer. In embodiments without the use of powder or granular material, this effect can also be achieved if the measuring and/or regulating element is embedded at a suitable point of the metal section or of the metal jacket of the tubular heating body.

The measuring and/or regulating element is preferably connected in series with at least one resistance wire winding of the tubular heating body in order to guarantee fast response times.

Another advantageous variant of the present invention makes provisions for at least one tube for passing through a fluid to be heated to have cross sections varying in contour in the direction in which it extends. Provisions are made in an advantageous variant for selecting crescent-shaped tube cross sections in the middle area, which makes good adaptation to the geometry of the tubular heating body possible, and for passing over in the end areas of the tubes to round cross sections, which can be connected especially easily. This possibility was not available until now due to the necessity of providing a groove or hole, into which the heater had to be inserted, and this led to an appreciable limitation of the design parameters for the flow heater. In particular, the present invention makes it possible for at least one tube for passing through a fluid to be heated to be shaped such that it can be pushed over the heater, but good transfer of the heat from the areas of the heater at which the tube is not directly in contact to the tube can be ensured at the same time via the powder or granular material. The heater can be operated with a higher output because of the heat dissipation thus improved.

The process according to the present invention for manufacturing such a flow heater comprises the following steps:

• • Providing a one-piece hollow section designed as a metal section or composed of a plurality of components, containing at least one metal section, with a heater arranged at least in some sections in the interior space of the hollow section and at least one tube for passing through a fluid to be heated, which is arranged at least in some sections in the interior space of the hollow section;
  • Filling at least part of the interior space of the hollow section with a sealing compound, a powder or granular material; and preferably pressing in, at least in some sections, of the heater and of the at least one tube into the hollow section.

It should be borne in mind, in particular, that depending on how the hollow section is designed, the step of filling may be carried out after providing the hollow section or it may be integrated in the providing step.

Structuring of the metal section, which was hitherto necessary, can be avoided due to this process just as completely as the laborious insertion of the heater and tubes for passing through a fluid to be heated, which leads to an especially simple and cost-effective manufacture with more degrees of freedom in design.

In a preferred embodiment of the process, a metal section is made available as a bottom element for providing a hollow section composed of a plurality of components containing at least one metal section. The heater and the at least one tube for passing through a fluid to be heated are arranged on or at the bottom element. This may also be carried out, for example, in fitted openings of the bottom element, which brings about an especially reproducible arrangement of the elements of the flow heater relative to one another.

In the further course of the process, the metal section provided in this embodiment as a bottom element is connected to at least one additional metal section, especially a cover element and/or at least one section of the wall of a tube for passing through a fluid to be heated in order to provide the hollow section. The filling of at least part of the interior space of the hollow section is preferably performed in this procedure before all the components of the hollow section are completely connected to one another.

An alternative advantageous embodiment of the metal section is obtained if the metal section is a tensioning mechanism for generating a pressure, which brings about the pressing into the metal section. The metal section may optionally additionally ensure the holding together of the tubular heating body and tubes. Flow heaters of this embodiment are especially compact and can be manufactured in a cost-effective manner. Another advantage of this embodiment is that very strong pressing-in pressures can be permanently applied, which leads to an especially intimate thermal contact of the components of the flow heater and thus permits good heat transmission. Tightening straps, tensioning clips or preformed, pressed sections are especially suitable for use as tensioning mechanisms. However, it is also possible to provide a tensioning mechanism by soldering or welding the tubes in the compressed state, after which the metal section can be seen in the soldered joints and/or weld seams.

Another, especially robust, alternative embodiment of the metal section is obtained if the metal section is a massive body, especially an aluminum or brass body, in which the pipe and tubular heating body are mounted and embedded, preferably pressed in. To facilitate the assembly of such an arrangement, holes may be provided in the metal section. In particular, it is also possible that the holes for the tubular heating body and tubes for passing through a fluid to be heated pass over into each other, so that the metal section forms the “frame” for these recesses. This facilitates the assembly of the flow heater.

The shape of the wall of at least one of the tubes for passing through a fluid to be heated, which said tubes surround the at least one tubular heating body, or of the tube for passing through a fluid to be heated, which said tube surrounds the tubular heating body, wherein said wall faces the tubular heating body, is adapted in an especially advantageous embodiment to a section of the surface of the tubular heating body. Especially good and homogeneous heat transfer is guaranteed hereby.

An adaptation in the sense of the present invention is already present if the same geometric shape is present, especially if the surface sections adapted to one another extend at constant distance from each other; there do not need to be mutually covering fitting surfaces. For example, surface segments of two concentric, cylindrical jacket surfaces with markedly different radii are thus fitted surface sections in the sense of the present invention.

It is advantageous, furthermore, if the shape of the wall of at least one of the tubes surrounding the at least one tubular heating body or of the tube surrounding the tubular heating body, which said wall faces away from the tubular heating body, is adapted to a section of the surface of the metal section facing away from the surrounding tubular heating body. This entails an especially homogeneous heat distribution on the surface of the flow heater.

If a metal section is provided, which has at least one web, via which the surface of the metal section, which said surface faces away from the tubular heating body, is connected to the tubular heating body, the advantage is gained that regulating and securing elements arranged on the outside of the flow heater can respond and effectively prevent overheating or even melting of the metal section. It is especially favorable if at least two tubes for passing through a fluid to be heated are provided, which overlap each other, when viewed from the surrounding tubular heating body in a direction at right angles to the direction in which it extends, at least in some sections, because homogeneous heat distribution is thus brought about on the surface of the flow heater.

An alternative advantageous embodiment of the flow heater makes provisions for a tube for passing through the fluid to be heated to enclose at least one tubular heating body. This leads to an especially homogeneous heat distribution, but is associated with a greater design effort.

An especially efficient heat transfer can be achieved in a situation in which the requirements of the space available for installation require an especially compact design if at least one of the tubes for passing through a fluid to be heated, which said tubes surround the at least one tubular heating body, is directly in contact with the surrounded tubular heating body.

If the smallest possible design is not absolutely necessary, a heat transport tube may be arranged on the tubular heating body. The size of the heated tube inner surface can thus be varied. This measure creates an additional degree of freedom for coordination between the desired fluid throughput and the needed heat output at a given length of the flow heater. Moreover, the thermal contact between the tubular heating body and tube for passing through a fluid to be heated can be improved by selecting a material with higher elasticity and/or lower hardness and/or better deformability compared to the material of the metal jacket of the tubular heating body, especially if the material of the heat transport tube has a higher thermal conductivity than the material of the metal jacket of the tubular heating body.

Provisions are made in an alternative variant of the flow heater to this, which is especially favorable in terms of manufacturing technology, for the tubular heating body being mounted in a hole in the metal section. Especially cost-effective flow heaters are obtained if the at least one tube for passing through a fluid to be heated is a drawn special section tube.

Especially good connection possibilities are obtained for the flow heater if adapter pieces are provided on at least one of the tubes for passing through a fluid to be heated.

Especially high safety against failure is achieved with a flow heater in which the tubular heating body is essentially unheated in the sections in which it can come into direct contact with the fluid to be heated, especially in sections which are not mounted in, preferably not pressed into, the metal section. This can be achieved, e.g., by means of areas in which the resistance wire is not arranged in a coiled or meandering pattern or is led through these areas over as direct a route as possible. Damage to the tubular heating body, which may be possible due to the contact with the fluid, and leads to the failure thereof, is thereby. For example, heat dissipation from the tubular heating body may be locally hindered in case of water due to the buildup of a layer of lime, which may lead to overheating and failure of the tubular heating body.

Another, especially advantageous form of the flow heater has a tube arrangement with at least two tubes for passing through fluid to be heated, which are intended to be connected to different fluid circuits. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a first exemplary embodiment of the present invention;

FIG. 1a is a sectional view along line A-A of the exemplary embodiment from FIG. 1;

FIG. 1b is a sectional view along line B-B of the exemplary embodiment from FIG. 1;

FIG. 2 is a perspective view of a second exemplary embodiment of the present invention;

FIG. 2a is a sectional view along line A-A of the exemplary embodiment from FIG. 2;

FIG. 2b is a sectional view along line B-B of the exemplary embodiment from FIG. 2;

FIG. 3 is a sectional view of a third exemplary embodiment of the present invention, corresponding to the section in FIG. 1b;

FIG. 4 is a sectional view of a fourth exemplary embodiment of the present invention, corresponding to the section in FIG. 2b;

FIG. 5 is a sectional view of a fifth exemplary embodiment of the present invention, corresponding to the section in FIG. 1b;

FIG. 6 is a sectional view of a sixth exemplary embodiment of the present invention, corresponding to the section in FIG. 1b;

FIG. 7 is a perspective view of a seventh exemplary embodiment of the present invention;

FIG. 7a is a sectional view along line B-B of the exemplary embodiment from FIG. 7;

FIG. 8 is a perspective view of an eighth exemplary embodiment of the present invention;

FIG. 8a is a sectional view along line A-A of the exemplary embodiment from FIG. 8;

FIG. 8b is a sectional view along line B-B of the exemplary embodiment from FIG. 8;

FIG. 9a is a perspective view of a ninth exemplary embodiment of the present invention;

FIG. 9b is a cross section of the exemplary embodiment from FIG. 9a;

FIG. 10a is a perspective view of a tenth exemplary embodiment of the present invention;

FIG. 10b is a cross sectional view through the exemplary embodiment from FIG. 10a;

FIG. 11a is a perspective view of an eleventh exemplary embodiment of the present invention;

FIG. 11b is a partially sectional view showing the interior of the exemplary embodiment from FIG. 11a;

FIG. 12a is a perspective view showing a twelfth exemplary embodiment of the present invention;

FIG. 12b is a perspective view showing the components of the exemplary embodiment from FIG. 2a before assembly;

FIG. 12c is a sectional view along line B-B of the exemplary embodiment from FIG. 12a;

FIG. 13a is a perspective view of a thirteenth exemplary embodiment of the present invention;

FIG. 13b is a perspective view showing the components of the exemplary embodiment from FIG. 13a before assembly;

FIG. 13c is a sectional view along line B-B of the exemplary embodiment from FIG. 13a;

FIG. 14a is a perspective view of a fourteenth exemplary embodiment of the present invention;

FIG. 14b is a cross sectional view through the exemplary embodiment from FIG. 14a along line A-A; and

FIG. 14c is a cross sectional view along line A-A in a variant of the exemplary embodiment from FIG. 14a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, identical reference numbers are used in all figures for identical components of the same exemplary embodiments.

FIG. 1 shows a flow heater 100 according to the present invention with a metal section 101 designed as a solid body, with a tubular heating body 102, which passes through the metal section 101 and is mounted and embedded and preferably pressed into the metal section 101 at least in some sections, and with a tube arrangement comprising two tubes 103, 104 for passing through a fluid to be heated, which pass through the metal section 101 and are mounted and preferably pressed into the metal section 101 in some sections. Adapter pieces 104, 105, 106, 107 are arranged at the ends of the tubes 103, 104 for passing through a fluid to be heated.

Based on the cross-sectional view shown in FIG. 1a along line A-A, the course of the tubular heating body 102 and of the tubes 103, 104 for passing through a fluid to be heated as well as the embedding thereof in the metal section 101 are seen especially clearly.

The section shown in FIG. 1b along line B-B shows especially clearly how the tubes 103, 104 for passing through a fluid to be heated surround the tubular heating body 102. This view shows the plane at right angles to the direction in which the tubular heating body 102 extends. Beginning from the tubular heating body 102, a section each of a tube 103, 104 for passing through a fluid to be heated is arranged in a plurality of directions between the tubular heating body 102 and the surface of the metal section 101, which surface faces away from the tubular heating body. The tubes 103, 104 thus surround the tubular heating body 102 in the sense of the present invention. However, the tubular heating body 102 is not enclosed, because webs 111, 112 connect the surface of the metal section 101 facing away from the tubular heating body 102 to the tubular heating body 102 in two directions.

Furthermore, FIG. 1b shows that in the tubes 103, 104, the wall facing the tubular heating body 102 or wall section 114, 113 facing said tubular heating body extends at a constant distance from a section of the surface of the tubular heating body 102. The wall sections 114, 113 are therefore adapted to the corresponding section of the surface of the tubular heating body 102.

Furthermore, this view shows as an example a typical inner structure of the tubular heating body 102, which is known per se, which has here, for example, within a metal section, a coil of a heat conductor embedded in an insulating material or a resistance wire.

FIGS. 2, 2a and 2b show a second embodiment of the present invention with a flow heater 200, a metal section 201, tubular heating bodies 202, 209, 210 a tube arrangement with tubes 203, 204, adapter pieces 205, 206, 207, 208 and webs 211, 212. Walls facing the tubular heating body are designated 213 and 214. The second embodiment differs from the view in FIGS. 1, 1a and 1b only in that the two additional tubular heating bodies 209, 210 are provided outside the tubes 203, 204. The additional tubular heating bodies 209, 210 can bring about an increase in the heating output of the flow heater 200 compared to flow heater 100. However, their output is limited, because they are not surrounded by tubes for passing through a fluid to be heated and may thus lead to an undesired heating of the surface of the flow heater 200. Because of the very good utilization and dissipation of the output of the central tubular heating body 202 by the tubes 203, 204 surrounding these, it is still possible to provide a limited additional heating output thanks to the present invention.

FIG. 3 shows a cross section as in FIG. 1b through a third embodiment of the present invention with a flow heater 300, a metal section 301, a tubular heating body 302, a tube arrangement with tubes 303, 304 and webs 311, 312. Walls facing the tubular heating body are designated 313 and 314. The third embodiment differs from the view in FIGS. 1, 1a and 1b only by the shape of the tubes 303, 304 for passing through a fluid to be heated. The embodiment according to FIG. 3 has tubes, whose respective wall 315, 316 facing away from the tubular heating body 302 is adapted to a section of the surface of the metal section 301, which said surface faces away from the tubular heating body 302.

FIG. 4 shows a cross section as in FIG. 2b through a fourth embodiment of the present invention with a flow heater 400, a metal section 401, tubular heating bodies 402, 409, 410 a tube arrangement with only one tube 403 and web 411. A wall facing the tubular heating body is designated 413. The fourth embodiment differs from the view in FIGS. 2, 2a and 2b only in that the surrounding, according to the present invention, of a tubular heating body 402 is achieved only by means of a tube 403, which is placed nearly completely around the tubular heating body 402, but a web 411 still continues to connect the surface of the metal section 401, which said surface faces away from the tubular heating body 402, to the tubular heating body 402.

FIG. 5 shows a cross section as in FIG. 1b through a fifth embodiment of the present invention with a flow heater 500, a metal section 501, a tubular heating body 502, a tube arrangement with tubes 503, 504 and webs 511, 512. Walls facing the tubular heating body are designated 513 and 514. The fifth embodiment differs from the view in FIGS. 1, 1a and 1b only by the shape of the tubes 503, 504 for passing through a fluid to be heated. The embodiment according to FIG. 5 has tubes 503, 504 for passing through a fluid to be heated, which not only surround the heat conductor 502—this would be achieved by the tube 503 alone—but together enclose it. Viewed from the surrounded tubular heating body 502, sections of the tubes 503, 504 for passing through a fluid to be heated are arranged in all directions at right angles to the direction in which the surrounded tubular heating body 502 extends. However, webs 511, 512 are still present, which connect the surface of the metal section 501, which surface faces away from the tubular heating body 502, to the tubular heating body 502. Thus, monitoring of the temperature of the metal section 501 in the interior thereof continues to be possible.

FIG. 6 shows a cross section as in FIG. 1b through a sixth embodiment of the present invention with a flow heater 600, a metal section 601, a tubular heating body 602, a tube arrangement with tubes 603, 604 and webs 611, 612. Walls facing the tubular heating body are designated 613 and 614. The sixth embodiment differs from the view in FIGS. 1, 1a and 1b slightly by the shape, but mainly by the arrangement of the tubes 603, 604 for passing through a fluid to be heated. The embodiment according to FIG. 6 has tubes 603, 604, whose respective wall 614, 613 facing the tubular heating body 602 is not only adapted to a section of the tubular heating body 602, but is in direct contact with same, which leads to an especially direct heat transfer to the fluid to be heated.

FIG. 7 shows a flow heater 700 according to the present invention with a metal section 701 and three tubular heating bodies 702, 703, 704, which pass through the metal section 701 and are mounted in and preferably pressed into the metal section 701 in some sections, and with a tube arrangement comprising six tubes 705, 706, 707, 708, 709, 710 for passing through a fluid to be heated, which pass through the metal section 701 and are mounted and especially pressed into the metal section 701 in some sections. Adapter pieces 711, 712, 713, 714 are arranged at the ends of the tubes 705, 706, 707, 708, 709, 710 for passing through a fluid to be heated. The adapter pieces 711, 712, 713, 714 are designed in this case such that when one of their ends is connected to a fluid supply, not shown here, a connection of three tube ends with the fluid supply is established via their other end by means of the adapter piece 711, 712, 713, 714, which makes possible an especially simple connection of the flow heater 700.

The section shown in FIG. 7a along line B-B shows especially clearly how the tubes 705, 706, 707, 708, 709, 710 for passing through a fluid to be heated surround the tubular heating body 702. This view shows the plane at right angles to the direction in which the tubular heating body 702 extends. Beginning from the tubular heating body 702, a section each of one of the tubes 705, 706, 707, 708, 709, 710 for passing through a fluid to be heated is arranged, namely, centrically symmetrically to the center of the cross section through the tubular heating body 702, in a plurality of directions between the tubular heating body 702 and the surface of the metal section 701, which said surface faces away from the tubular heating body. The radial distance between the tubes 705, 706, 707, 708, 709, 710 is equal.

Thus, the tubes 705, 706, 707, 708, 709, 710 surround the tubular heating body 702 in the sense of the present invention. However, the tubular heating body 702 is obviously not enclosed here, either, because a web 715, 716, 717, 718, 719 720 each of the metal section is present between two adjacent tubes.

The additional tubular heating bodies 703, 704 can bring about an increase in the heat output of the flow heater 700 compared to the flow heater 100. However, the output of the additional tubular heating bodies 703, 704 is limited, because they are not surrounded by tubes for passing through a fluid to be heated and may thus lead to an undesired heating of the surface of the flow heater 700. It is still possible to provide a limited additional heat output thanks to the present invention because of the very good utilization and dissipation of the output of the central tubular heating body 702 by the tubes 705, 706, 707, 708, 709, 710 surrounding said tubular heating body.

FIG. 8 shows a flow heater 800 according to the present invention with a metal section 801, with a tubular heating body 802, which passes through the metal section 801 and is mounted and especially pressed into the metal section 801 in some sections, and, as can be seen only on the basis of FIG. 8b, with six tubes 805, 806, 807, 808, 809, 810 for passing through a fluid to be heated, which pass through the metal section 801 and are mounted in and especially pressed into the metal section 801 in some sections. Respective adapter pieces 803 and 804, through which the tubular heating body 802 passes, are arranged at the respective first and second ends of the tubes 805, 806, 807, 808, 809, 810 for passing through a fluid to be heated. It is essential in this connection that the tubular heating body 802 has, in the areas in which it is passed through the adapter pieces 803, 804, essentially unheated areas, in which the resistance wire, in particular, is not arranged in a coiled or meandering pattern. Damage to the tubular heating body, which may be possible due to contact with the fluid and leads to the failure thereof, is avoided hereby. For example, heat dissipation from the tubular heating body may be locally hindered in case of water due to the buildup of a layer of lime, which may lead to overheating and failure of the tubular heating body. All sections of the tubular heating body, which are not mounted in the metal section 801, are essentially unheated in an especially preferred embodiment of the flow heater.

It is seen especially clearly from the cross-sectional view shown in FIG. 8a along line A-A that the adapter pieces 803, 804 are in connection with all tubes 805, 806, 807, 808, 809, 810 for passing through a fluid to be heated. This is especially favorable in terms of connection technology and permits the use of large cross sections in the feed areas 803a, 804a of the adapter pieces 803, 804. In addition, this contributes to a more uniform flow through the tubes 805, 806, 807, 808, 809, 810 for passing through a fluid to be heated. The adapter pieces 803, 804 are directly in contact with the metal section 801 in the exemplary embodiment according to FIG. 8, which leads to an especially compact design, but an arrangement, not shown, in which they are arranged at spaced locations from the metal section 801, is possible as well.

Furthermore, the course of the tubular heating body 802 and of the tubes 805, 806, 807, 808, 809, 810 for passing through a fluid to be heated as well as the embedding thereof in the metal section 801 are seen.

The section shown in FIG. 8b along line B-B shows especially clearly how the tubes 805, 806, 807, 808, 809, 810 for passing through a fluid to be heated surround the tubular heating body 802. This view shows the plane at right angles to the direction in which the tubular heating body 802 extends. Beginning from the tubular heating body 802, a section each of one of the tubes 805, 806, 807, 808, 809, 810 for passing through a fluid to be heated is arranged in a plurality of directions between the tubular heating body 802 and the surface of the metal section 801, which said surface faces away from the tubular heating body. Thus, they surround the tubular heating body 802 in the sense of the present invention. However, the tubular heating body 802 is not enclosed, because webs 811, 812, 813, 814, 815, 816 connect the surface of the metal section 801, which the surface faces away from the tubular heating body 802, to the tubular heating body 802.

Furthermore, this view shows as an example a typical inner structure of the tubular heating body 802, which is known per se, which has here, for example, within a metal section, a coil of a heat conductor embedded in an insulating material or a resistance wire.

FIG. 9a shows a flow heater 900, which has a tube arrangement comprising two tubes 905, 906 for passing through a fluid to be heated, which are arranged such that they surround a tubular heating body 903. As can be seen especially clearly from FIG. 9b, the sections of the walls of the tubes 905, 906, which said sections face the tubular heating body 903, are adapted to the shape of the tubular heating body 903 and are in direct contact with the surface thereof.

Furthermore, metal sections 901 in the form of tensioning mechanisms are seen at three points of the flow heater 900, but it is also possible to use more or fewer such points as needed. These tensioning mechanisms bring about the pressing in of tubes 905, 906 and tubular heating body 903 in the metal sections 901.

This embodiment of the present invention is characterized, on the one hand, by an especially compact design and a very cost-effective manufacture, and, on the other hand, it also permanently ensures an intimate thermal contact, because the pressing-in pressure is continuously maintained by the metal sections 901.

The tenth exemplary embodiment of the present invention, which is shown in FIGS. 10a and 10b comprises a flow heater 1000, a metal section 1001, a tubular heating body 1002, a tube arrangement with tubes 1005, 1006. The tenth exemplary embodiment differs from the embodiment according to FIGS. 9a and 9b, to the description of which reference is made in view of the identical features, only in that, as can be seen especially clearly from FIG. 10b, an additional jacket tube is pushed in the tenth exemplary embodiment as a heat transport tube 1017 over the tubular heating body 1002, so that the thermal contact between the tubes 1005, 1006 and the tubular heating body 1002 is indirect, taking place via the heat transport tube 1017. This measure creates an additional degree of freedom for coordination between the desired fluid throughput and the needed heat output at a given length of the flow heater 1000, so that the size of the heated tube inner surface can be varied. Moreover, the thermal contact between the tubular heating body 1002 and the tubes 1002, 1003 for passing through a fluid to be heated can be improved by selecting a material with higher elasticity and/or lower hardness and/or better deformability compared to the material of the metal jacket of the tubular heating body 1002, especially if the material of the heat transport tube 1017 has a higher thermal conductivity than the material of the metal jacket of the tubular heating body.

Prefixing of the components relative to one another, e.g., by a soldered connection or another connection, may be optionally carried out in the embodiments shown in FIGS. 9a, 9b, 10a and 10b. However, the metal section is essential for ensuring the needed pressing-in pressure, which is essential for achieving the desired intimate thermal contact between the tubular heating body and tube.

FIG. 11a shows an eleventh exemplary embodiment of a flow heater 1100. A hollow section 1101 made of metal, which is designed as a cylindrical tube, is seen. End sections of a tube 1102 for passing through a fluid to be heated project from the wall of the hollow section 1101. A heater 1103 in the form of a tubular heating body has electric terminals 1104, 1105, which project on the front side, which are not shown in the view of the other embodiments for reasons of clarity, and are arranged concentrically in the cylindrical tube 1101. The inner volume of the hollow section 1101, which is not filled out by the heater 1103 and tube 1102 for passing through a fluid to be heated, is filled with a powder or granular material 1106, but this cannot be seen in FIG. 11a, because it is covered by the hollow section 1101 and a front-side closing plate 1107.

FIG. 11b shows a view into the interior of the exemplary embodiment from FIG. 11a, which is seen when cutting open the hollow section 1101 along a diameter of the cross-sectional area, removing the part facing the viewer and removing the powder or granular material 1106 up to the cut surface. Thus, this is not, in particular, a cross-sectional view, because neither the tube 1102 for passing through a fluid to be heated nor the heater 1103 are shown in sectional views. It is clearly seen in FIG. 11b that the tube 1102 for passing through a fluid to be heated is wound around the heater 1103 in coils such that the two ends of the tube are arranged at the same end of the flow heater 1100. Any other desired shape of the tube 1102 for passing through a fluid to be heated is possible, in principle, e.g., it may be wound in a meandering pattern or designed such that the two ends of the tube are arranged at different ends of the flow heater 1100. The powder or granular material may become self-supporting due to compaction, so that the front-side closing plates 1107, 1108 optionally provided on the front sides of the flow heater 1100 in this exemplary embodiment are not absolutely necessary.

The considerable advantages of the manufacture according to the present invention of the flow heater can also be easily illustrated on the basis of the view in FIG. 11b. It was always necessary in hitherto ordinary flow heaters to ensure good thermal contact between the heater 1103 and tube 1102 for passing through a fluid to be heated by high-precision manufacture and/or by pressing in strongly. This applied especially to embodiments in which the shape of the tube 1102 for passing through a fluid to be heated prevents insertion into a groove of an extruded section, as this is the case in the example shown in FIG. 11b, because the heat transfer must now be guaranteed completely by the direct contact between the heater 1103 and tube 1102, which cannot be guaranteed solely by simply attaching the tube 1102 for passing through a fluid to be heated to the heater 1003.

By contrast, only the hollow section 1101, tube 1102 and heater 1103 must be provided to manufacture the flow heater shown in FIGS. 11a and 11b, where the heater 1103 and tube 1102 are arranged at least in some sections in the interior space of the hollow section 1101, which is achieved by these components being either first attached to each other and then inserted into the interior space of the hollow section 1101 or by one of the components being arranged first in the interior of the hollow section 1101 and the second being then attached.

The filling of at least part of the interior space of the hollow section 1101 with a powder or granular material 1106 may subsequently take place, for example, in a forging die, and the heater 1101 and/or the at least one tube is then advantageously optionally mounted and preferably pressed into this.

Good thermal contact is ensured with this procedure by the powder or granular material 1106 even at points where inaccuracies due to the manufacturing technology or even the clearance necessary for pushing the tube 1102 over the heater 1103 have hitherto impaired this contact.

FIG. 12a shows a view of a twelfth exemplary embodiment of a flow heater 1200 according to the present invention with a hollow section 1201, whose cross section is essentially rectangular. Two tubes 1202, 1204 for passing through a fluid to be heated, which are mounted at least in some sections in the inner volume of the hollow section, are provided in this exemplary embodiment. A heater 1203, which is designed as a tubular heating body, is arranged between the tubes 1202, 1204 for passing through a fluid to be heated. Two optional measuring or regulating elements 1207, 1208, which monitor the flow heater 1200 during operation and collect data for regulating same and/or convert those data into control commands, with which, e.g., the flow velocity of the fluid or heat output, which is made available by the heater 1203, can be regulated, are provided on the outside of the hollow section.

As can be seen especially clearly from the sectional view along line B-B according to FIG. 2c, the tubes 1202, 1204 for passing through a fluid to be heated and the heater 1203 are embedded in a powder or granular material in the area in which they extend within the hollow section 1201, as a result of which good thermal contact is ensured. It can also be seen especially clearly in FIG. 2c that the tubes 1202, 1204 for passing through a fluid to be heated have wall sections 1202a, 1204a, whose shape is adapted to the shape of the wall section of the heater 1203 located closest, as a result of which an especially good heat transfer can be ensured.

FIG. 12b shows the components of the exemplary embodiment from FIG. 12a before assembly. As a consequence of the embedding of the tubes 1202, 1204 and of the heater 1203 in a powder or granular material, the tubes 1202, 1204 for passing through a fluid to be heated can be inserted with the desired section into the hollow section 1201 in a simple manner and heater 1203 can then be placed between the tubes 1202, 1204, even though the shape of the tubes 1202, 1204 itself is such that direct insertion into a groove of an extruded section, as is known from the state of the art, would not be possible. The assembly unit thus provided can then with filled with a powder or granular material, optionally preferably compacted and, if desired, optionally closed with front-side closing plates, not shown.

FIG. 13a shows a view of another exemplary embodiment of the present invention. A flow heater 1300 with two tubes 1302, 1304 for passing through a fluid to be heated and with a heater 1303 are seen. One of two metal sections 1301, 1305, which are connected to wall sections of the tubes 1302, 1304 and represent components of a hollow section formed together with these wall sections, can be seen in the view in FIG. 13a.

As can be seen especially clearly in the sectional view according to FIG. 13c, the inner volume of the flow heater, which is defined by the metal sections 1302, 1305 and the wall sections 1302a, 1304a of the tubes 1302, 1304 for passing through a fluid to be heated, is filled with a powder or granular material 1306, in which, when viewed in the cross section, the tubes 1302, 1304 are thus partly embedded and in which heater 1303 is completely embedded. As described above in connection with FIG. 12c, wall sections of the tubes 1302, 1304 are adapted to the outer contour of heater 1303.

FIG. 13b shows the components of the exemplary embodiment from FIG. 13a before assembly. The hollow section is provided in this case by the tubes 1302, 1304 being fastened to one of the metal sections 1301, 1305. Front-side closing plates 1307, 1308 are fastened to the same metal section 1302, 1305 before or after the heater 1303 was pushed in between them. The inner volume can then be filled with a powder or granular material before fastening the second metal section 1305, 1301 and an optional compaction may be subsequently carried out.

FIG. 14a shows an exemplary embodiment of the present invention, which differs from the design according to FIGS. 10a and 10b only in that the tensioning means are formed here by tensioned metal sections 1401, 1401a rather than being arranged only locally, as can be seen in FIG. 10a, but they extend essentially over the entire effective length of the flow heater, as is shown in FIG. 14a.

The two variants of this embodiment, which are shown in FIGS. 14b and 14c, differ in that the space between the tips of the crescents remains free between the tubes 1402, 1404 with crescent-shaped cross section in the embodiment according to FIG. 14b, so that, for example, a measuring and/or regulating element, e.g., in the form of a thermocouple, can be provided there, whereas the variant according to FIG. 14c has projections of the metal section 1401a at these points, which leads to a more homogeneous dissipation of heat.

In all embodiments, which have more than one tube for passing through a fluid to be heated, different fluid circuits can be supplied with the different tubes. The possibility of providing different amounts of fluid with a flow heater, which is made possible by the design according to the present invention, is pointed out in this connection, in particular.

Features that can be found only in some of the embodiments can be combined with the other embodiments shown unless they contradict features of these embodiments.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

LIST OF REFERENCE NUMBERS

• A-A Section line
• B-B Section line
• 100, 200, 300, 400, 500, 600, 700, 800 Flow heater
• 101, 201, 301, 401, 501, 601, 701, 801 Metal section
• 102, 202, 209, 210, 302, 402, 409, 410, 502, 602, 702, 703, 704, 802, 902, 1002 Tubular heating body
• 103, 104, 203, 204, 303, 304, 403, 503, 603, 604, 705, 706, 707, 708, 709, 710, 805, 806, 807, 808, 809, 810, 905, 906, 1005, 1006 Tube
• 105, 106, 107, 108, 205, 206, 207, 208, 711, 712, 713, 714, 803, 804 Adapter piece
• 111, 112, 211, 212, 311, 312, 411, 511, 512, 611, 612, 715, 716, 717, 718, 719, 720, 811, 812, 813, 814, 815, 816 Web
• 113, 114, 213, 214, 313, 314, 413, 513, 514, 613, 614 Wall facing tubular heating body
• 315, 316 Wall facing away from tubular heating body
• 1017, 1417 Heat transport tube
• 1100, 1200, 1300, 1400 Flow heater
• 1101, 1201, 1401, 1401a Hollow section
• 1102, 1202, 1204, 1302, 1304, 1402, 1404 Tube
• 1202a, 1204a, 1302a, 1304a Wall section of tube
• 1103, 1203, 1303, 1403 Tubular heating body
• 1104, 1105 Electric terminals
• 901, 1001, 1301, 1305 Metal section
• 1106, 1206, 1306 Powder or granular material
• 1107, 1108, 1307, 1308 Front-side closing plate
• 1207, 1208 Measuring or regulating element

Claims

1. A flow heater comprising:

a metal section;

a tube arrangement with a tube interior space for passing through fluid to be heated, said tube arrangement being pressed into said metal section at least in some sections; and

a tubular heating body arranged outside said tube interior space, said tubular heating body being at least one of mounted in and pressed into said metal section at least in some sections, said tubular heating body being surrounded, at least in some sections, by said tube arrangement for passing through fluid to be heated.

2. A flow heater in accordance with claim 1, wherein said metal section forms a hollow section or comprises a component of a composite hollow section, in which said tubular heating body and said tube arrangement are arranged and pressed in, at least in some sections, together with a sealing compound, in which at least one of said tubular heating body and said tube arrangement are embedded at least partly.

3. A flow heater in accordance with claim 1, wherein said metal section is a hollow section or comprises a component of a composite hollow section, in which said tubular heating body and said tube arrangement are arranged and pressed in, at least in some sections, together with a powder or granular material, in which said tubular heating body and/or said tube arrangement are embedded at least partly.

4. A flow heater in accordance with claim 1, wherein said hollow section comprises two metal sections connected to one another.

5. A flow heater in accordance with claim 2, wherein:

said tube arrangement has a wall section; and

said hollow section comprises a composite hollow section and said wall section forms a component of said composite hollow section and said metal section forms a component of said composite hollow section.

6. A flow heater in accordance with claim 5, wherein:

said tube arrangement comprises at least two tubes for passing fluid to be heated, each of sad tubes having a wall section to provide wall sections;

said composite hollow section comprises another metal section to provide metal sections;

said composite hollow section is formed from said wall sections and said metal sections, which metal sections connect said wall sections of the tube arrangement to one another.

7. A flow heater in accordance with claim 2, wherein said tube arrangement comprises at least one tube directly in contact, at least in some sections, with said heating body.

8. A flow heater in accordance with claim 3, wherein said metal section is formed of a material that has a lower thermal conductivity than said powder or granular material.

9. A flow heater in accordance with claim 3, further comprising a measuring and/or regulating element arranged on an outside of said metal section or embedded in said powder or granular material or embedded in said metal section or embedded in a metal jacket of said tubular heating body.

10. A flow heater in accordance with claim 9, wherein said measuring and/or regulating element is connected in series with a resistance wire winding of said tubular heating body.

11. A flow heater in accordance with claim 1, wherein said tube arrangement comprises a tube having varying cross sections in contour including a crescent-shaped cross sectional portion and a round cross sectional portion in said end area in the direction in which it extends.

12. A flow heater in accordance with claim 1, wherein said tube arrangement comprises a tube that is pushed over said tubular heating body.

13. A flow heater in accordance with claim 1, wherein said metal section comprises a tensioning mechanism for generating a pressure, which brings about a pressing of said tube arrangement into said metal section.

14. A flow heater in accordance with claim 1, wherein said metal section comprises a solid body comprising at least one of a steel, an aluminum and a brass body, in which said tube arrangement and said tubular heating body are at least one of mounted and pressed.

15. A flow heater in accordance with claim 1, wherein said tube arrangement includes a tube with a wall section which faces said tubular heating body and has a shape adapted to a section of a shape or geometry of a surface of said tubular heating body.

16. A flow heater in accordance with claim 1, wherein said tube arrangement includes a tube with a wall section which faces away from said tubular heating body and has a shape adapted to a shape or geometry of a surface of said metal section, which said surface of said metal section faces away from said tubular heating body.

17. A flow heater in accordance with claim 1, wherein said metal section has at least one web, via which a surface of said metal section, which said surface faces away from said tubular heating body, is connected to said tubular heating body.

18. A flow heater in accordance with claim 1, wherein said tube arrangement comprises two tubes for passing through fluid to be heated, said two tubes overlapping each other, in said at least in some sections in which said tubular heating body is surrounded, viewed from said tubular heating body in a direction at right angles to the direction in which said said tubular heating body extends.

19. A flow heater in accordance with claim 1, wherein:

said tube arrangement comprises a tube for passing through fluid to be heated; and

said tube encloses said tubular heating body.

20. A flow heater in accordance with claim 1, wherein:

said tube arrangement comprises plural tubes for passing through fluid to be heated; and

at least one of said tubes is directly in contact with the surrounded said tubular heating body.

21. A flow heater in accordance with claim 1, further comprising a heat transport tube surrounding said tubular heating body wherein:

said tube arrangement comprises plural tubes for passing through fluid to be heated; and

at least one of said tubes is in contact with said heat transport tube.

22. A flow heater in accordance with claim 21, wherein said heat transport tube is formed of a material with a higher thermal conductivity and/or a higher elasticity and/or a lower hardness and/or a better deformability than a material of an outer metal jacket of said tubular heating body.

23. A flow heater in accordance with claim 14, wherein said tubular heating body is mounted in a hole in said metal section.

24. A flow heater in accordance with claim 1, wherein said tubular heating body comprises unheated sections which come into direct contact with fluid to be heated, said unheated sections being not mounted in or not pressed into said metal section.

25. A process for manufacturing a flow heater comprising the steps of:

providing a metal section, a tube arrangement with a tube interior space for passing through fluid to be heated and a tubular heating body arranged outside the tube interior space; and

filling at least part of the interior space of the hollow section with a sealing compound, a powder or granular material.