EP3737207A1 - Heater arrangement - Google Patents

Abstract

In the case of a heating arrangement with a flat heating element (1) and a component (12) to be heated, the flat heating element (1) consists of a metal core or IMS circuit board (Insulated Metallic Substrate), in which a metal core or substrate is interposed with an insulating layer carries a copper layer and the copper layer is designed as a heating conductor track. The flat heating element (1) with the metal core or substrate is mounted flat against the component (12) to be heated, in contact with the latter.

Description

The invention relates to a heating arrangement with a heating element which lies flat against a component to be heated.

With many measuring and analysis devices, the influence of the ambient temperature on the measurement or analysis result can be prevented by means of a defined temperature control of the structure. In gas analysis, heating devices are also used when the gas to be analyzed contains moisture and condensation in the device is to be prevented. There are also gas analyzers with gas sensors, in particular based on semiconductor metal oxides, which have to be heated in order to be able to measure meaningfully at all. Gas chromatographs often require heating of the separation column in order to achieve the desired separation properties, or the sample to be analyzed is a liquid that has to be evaporated before it enters the separation column.

In the cases mentioned, the entire device can be heated, for example, by means of a circulating air heater, or the temperature is only controlled at the points where this is necessary in order to keep the overall heat supply small. Often the structures to be heated are geometrically complex and the available space is very limited, so that either heating elements in expensive custom-made products are required or heating elements in the form of point-like or concentrated heat sources have to be used.

The invention is therefore based on the object of enabling targeted and individual temperature control or heating of components, in particular of components of measuring and analysis devices, with simple means and using generally available standard components.

According to the invention, the object is achieved by the heating arrangement defined in claim 1, of which advantageous developments are given in the subclaims.

The subject of the invention is thus a heating arrangement with a flat heating element and a component to be heated, the flat heating element consisting of a metal core or IMS circuit board, in which a metal core or substrate with an insulating layer in between carries a copper layer, the copper layer at least in some areas is designed as a heating conductor track and the flat heating element with the metal core or substrate is mounted flat against the component to be heated, adjacent to the latter.

Metal core or IMS circuit boards (Insulated Metallic Substrate) are usually made up of an aluminum or copper carrier forming the metal core or the metal substrate, an insulation layer and a thin copper foil and are usually used to cool electronic power components or circuits that mounted on the IMS circuit board.

Instead of dissipating heat from components to a heat sink, metal core or IMS circuit boards are used according to the invention in order to generate heat through a power drop across the resistance of a conductor track and to dissipate it to the component to be heated.

The heating conductor track can be designed in a meandering shape, wherein it covers a predetermined area.

The heating output can be easily adapted to the existing conditions, with the achievable power density being very high. Even on small elements of e.g. B. 20 mm x 40 mm, conductor lengths of over a meter can be realized, which results in a resistance of approx. 5 ohms with a conductor path width of 0.15 mm.

The heating power can be individually distributed over the area via the conductor track density, distribution and widths, in order to e.g. B. to achieve symmetrical temperature profiles or targeted local heating. In the case of a single heating element, the heating conductor track can also be designed in the form of two or more separate heating circuits. It is also possible for two or more heating elements to be mounted at different points on a component to be heated. When using IMS circuit boards manufactured in the manufacturer's standard process, the heating elements according to the invention are suitable up to about 100 ° C. In the case of special solutions with a ceramic dielectric between the metal substrate and the copper layer, higher temperatures can also be reached.

The heating elements according to the invention are very flat (typically between 0.5 mm and 1.5 mm) and thus save space. They can be installed using simple screw connections through boreholes in the heating elements, and countersinks for countersunk screws can also be easily implemented for particularly flat installation. In order to enable optimal heat transfer between the heating elements and the components to be heated, the heating elements can be mounted on the components to be heated with the interposition of a thermal paste.

The outer contours of the flat heating elements can be adapted to those of the components to be heated; they can rest flat or possibly curved flat on the respective components.

The power supply of the heating circuit or the heating circuits can be via regular plugs or couplings, e.g. B. in the form of SMD components on the copper layer. The heating elements on the side with the copper layer can also be equipped with active elements such as LEDs for function control and / or temperature sensors for cost-saving implementation of temperature control.

Fig. 1

ein Beispiel für das flächige Heizelement auf Basis einer IMS-Leiterplatte,

Fig. 2

ein Beispiel für den Lagenaufbau einer IMS-Leiterplatte,

Fig. 3

ein Beispiel für die erfindungsgemäße Heizanordnung,

Fig. 4

unterschiedliche Beispiele für das flächige Heizelement und

Fig. 5

ein weiteres Beispiel für das flächige Heizelement.

The invention is further explained by way of example with reference to the figures of the drawing; show in detail:

Fig. 1

an example of the flat heating element based on an IMS circuit board,

Fig. 2

an example of the layer structure of an IMS circuit board,

Fig. 3

an example of the heating arrangement according to the invention,

Fig. 4

different examples of the flat heating element and

Fig. 5

another example of the flat heating element.

Fig. 1 shows an example of a flat heating element 1 based on an IMS printed circuit board 2 with a copper layer which is designed as a heating conductor track 3. The heating conductor 3 runs in a meandering shape over almost the entire surface of the heating element 1 and ends in two contact surfaces 4, 5 for soldering on power supply lines, not shown here. There are also contact surfaces 6 for soldering an SMD connector, also not shown. The IMS circuit board 2 contains two bores for mounting the heating element 1 on a component to be heated.

Fig. 2 shows an example of the basic layer structure of the IMS circuit board 2 with a metal core (metal substrate) 9, for example made of aluminum or copper, which bears the copper layer 11 with an insulating layer 10 in between.

Fig. 3 shows an example of the heating arrangement according to the invention, wherein at different points of a component to be heated 12, here z. B. an analysis chamber of a gas analyzer, two flat heating elements 13, 14 with the interposition of a thermal paste 15 are mounted. It is mounted using screws 16, 17 through the in Fig. 1 shown drill holes. The external dimensions and design of the external contours of the two flat heating elements 13, 14 are adapted to the respective heating task and the component 12 to be heated.

Fig. 4 shows examples of planar heating elements 18 with different external dimensions and designs of the external contours.

Fig. 5 shows another example of a flat heating element 19 with boreholes 7, 8 for assembly, a meandering heating conductor track 3, contact surfaces 6 for soldering an SMD connector, a pick-up coil 20 for detecting an external magnetic field. In the example shown, a pole piece (not shown here) can be passed through a recess 21 in the heating element as part of a transformer magnetic circuit, the transmission rate being defined by the number of turns of the pick-up coil 20.

Claims (7)

Heating arrangement with a flat heating element (1) and a component (12) to be heated, the flat heating element (1) consisting of a metal core or IMS circuit board (Insulated Metallic Substrate) (2), in which a metal core or substrate ( 9) bears a copper layer (11) with an insulating layer (10) in between, the copper layer (11) is at least partially designed as a heating conductor track (3) and the flat heating element (1) with the metal core or substrate (9) is flat the component (12) to be heated is mounted adjacent to it. Heating arrangement according to Claim 1, characterized in that the flat heating element (1) contains at least one borehole (7, 8) through which it is screwed to the component (12) to be heated. Heating arrangement according to Claim 1 or 2, characterized in that the flat heating element (1) is mounted on the component (12) to be heated with the interposition of a heat-conducting paste (6). Heating arrangement according to one of the preceding claims, characterized in that the outer contour of the flat heating element (1) is adapted to that of the component (12) to be heated. Heating arrangement according to one of the preceding claims, characterized in that the heating conductor track (3) is designed in a meandering shape and covers a predetermined area. Heating arrangement according to one of the preceding claims, characterized in that the heating conductor track (3) is designed in the form of at least two heating circuits. Heating arrangement according to one of the preceding claims, characterized in that at least one temperature sensor is arranged on the copper layer (11).

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