DE202011001278U1 - Temperature sensor for measuring high temperatures of gaseous and / or liquid media - Google Patents

Abstract

Temperature sensor for measuring high temperatures of gaseous and liquid media with a temperature-dependent measuring element and a metallic holder part, whereby the holder part is connected to process connection components and the lower end of the holder part is designed as a jacket (4) and protrudes into the medium to be measured and inside the holder part Inner lead wires (7) run which connect the measuring element to an electrical connection, characterized in that the jacket (4) is provided with micro-compression in the area in which the temperature-dependent measuring element is arranged, the micro-compression consisting of longitudinal grooves or lamellae which run parallel to the protective tube axis.

Description

The invention relates to a temperature sensor for measuring high temperatures of gaseous and / or liquid media with a temperature-dependent measuring element and a metallic socket part, wherein the socket part is connected to process connection components and the lower end of the socket part is designed as a protective tube and projects into the medium to be measured and in Inside the socket part inner conductor wires run, which connect the measuring element with an electrical connection.

The invention is suitable for use in industrial processes with high temperatures, preferably in exhaust gas temperature strands of high-performance engines and in compressor or diffuser units of gas turbines.

As temperature sensors measuring resistors or thermocouples can be used. Mostly they are designed as thermocouples. Such temperature sensors are characterized by low T ₅₀ and T _{90 time} percentage characteristics.

Temperature sensors are known from the prior art in various embodiments.

The US 2 611 791 describes a temperature sensor, in particular for measuring high temperatures of gases in jet engines. In a ceramic body while two electrical lines are arranged in bores along the ceramic body. The lines are mounted by means arranged within the holes inserts contactless to the ceramic body and connected to one another at one end of the ceramic body. The inserts may be elastic and / or made of resin.

In US 6 059 453 For example, there is described a temperature sensor for measuring temperature in a fluid having a temperature responsive electrical element partially encapsulated by a sapphire sheath. The sapphire sheath and the electrical element are surrounded by a ceramic sheath which is exposed to the fluid. The ceramic envelope is permeable to certain gases for which the sapphire sheath is impermeable. Two leads leading to the electrical element are electrically and thermally isolated from each other by an insulator, which preferably consists of a ceramic material. The conductors can be covered with insulating silicone.

To DE 102 38 628 B4 a high temperature sensor is known in which at least one of its inner conductor wires is provided with a high temperature resistant insulation and in a protective tube is a ceramic molding with a ceramic powder filling, the proportions of oxygen-releasing oxides are mixed.

Furthermore, in DE 10 2008 029 227 A1 a temperature sensor for measuring high temperatures gaseous and / or liquid media containing a temperature-dependent measuring element and a metallic socket part. In this case, a microstructure of a depth of 20 .mu.m to 80 .mu.m is applied to a cladding with a laser processing or with a microlithographic process.

A disadvantage of the described arrangements in addition to the complex and thus costly production also that only a few of the loads occurring is encountered, so that the causes of measurement errors and malfunctions metrological, electrical or mechanical nature are not generally eliminated. In particular, the desired upper service temperature limit is not reached, even if the dynamic and static thermal requirements are met.

At the in DE 10 2008 029 227 described temperature sensor is also disadvantageous that enforce the microstructures, in particular the grooves with deposits in certain media conditions.

The invention has for its object to provide a temperature sensor of the type mentioned, with the optimal measurement dynamic and static-thermal properties can be achieved even at high operating temperatures. Furthermore, the temperature sensor should have a long service life and be resistant to deposits on the sensor tube.

According to the invention the object is achieved with an arrangement which contains the features specified in claim 1.

Advantageous embodiments are the subject of the dependent claims.

The temperature sensor according to the invention has a metallic shell, which is provided with a micro-compression in the region in which the temperature-dependent measuring element is arranged. The micro-compression consists of lamellae or longitudinal grooves, which run parallel to the protective tube axis.

To further improve the surface of the jacket grooves can have in the form of rings, which are preferably arranged in the region of the slats or longitudinal grooves.

It is advantageous to make the depth and / or the width of the micro-compression smaller than the flow boundary layer of the flowing medium to be formed on the measuring sensor. The micro-compression is generally carried out with a depth or height of 50 .mu.m to 500 .mu.m, preferably 100 .mu.m to 300 .mu.m.

Advantageously, the height or depth of the micro-crimping is made smaller than the distance between adjacent fins.

To improve the heat transfer and thus also the response time, the jacket can have a taper in the region in which the micro-compression is arranged.

Furthermore, it is expedient that a kugelkalotten- or conically shaped tip connects to the front portion of the protective tube, which has the micro-compression.

An advantageous embodiment provides that the micro-compression is provided with a thin additional layer. The additional layer is preferably boron nitride or a carbide layer. It prevents corrosion and fouling of the thermowell, thereby ensuring that the improved response is maintained over the life of the thermistor.

Advantageously, the additional layer of microcompression on a layer thickness of 10 ... 20 nm.

Furthermore, it is expedient that the layer on the micro-compression has a relevance to the wavelength of the heat radiation, d. H. In the area of thermal radiation, the color influences the absorption and reflection properties of the protective tube tip. Preferably, the micro-compression is carried out so that the applied color-relevant layer has a high reflectance at high temperatures.

The micro-compression is in an advantageous embodiment of a conically shaped protective tube part with hexagonal or round cross-section. The deformation can be done several times.

The micro-compression can be manufactured by means of a multi-jaw hydraulic press. Jaw shape and jaw spacing determine the resulting lamellar shape, d. H. Longitudinal lamellae form along the sensor tube axis. The lamellar formation can be created very filigree and crack-free.

With the arrangement according to the invention, a favorable t ₉₀ time is achieved with relatively thick protective tube walls as well as a high long-term stability at high temperatures and flow loads.

Embodiments of the invention are explained in more detail below with reference to drawings. Showing:

1 the side view of the temperature sensor

2 a section AA, and

3 the measuring tip with micro profiling in side view.

In 1 the side view of a jacket thermocouple is shown. The rear, the measuring element facing away from the shaft 4 dar. From the upper part of the jacket thermocouple protrude the connecting wires 7 out. The front part forms the measuring tip 3 , This part is tapered and has a micro-crimping produced by micro-pressing 5 Mistake. It is advantageous that only the shaft 4 of the jacket thermocouple in the region of the measuring tip with a taper 2 is executed. Therefore, only one deformation is required in the production, so that the risk of cracking can be kept low. This makes it possible to safely in the area of the measuring tip 3 to perform the micro-compression. Through the compression arise in the front longitudinal slats, the micro-compression 5 form. Downwards, ie toward the measuring medium, the closing element closes on it 1 at. The micro-compression 5 is produced with a hydraulic press, whereby by their jaw design the shape of the micro-compression 5 can be influenced. The micro-compression 5 is preferably produced in the form of raised lamellae or grooves.

2 shows in section AA the profile of a micro-compression. The longitudinal lamellae created during micro-compression enlarge the effective surface of the temperature sensor and thus improve the heat transfer. The height of the slats is less than the distance between adjacent slats. Their height is preferably 100 microns to 300 microns. In the case shown, the micro-compression of lamellas with triangular cross-section, which protrude from the pipe surface.

At the in 3 micro-pressing shown are the lamellae or longitudinal grooves by milled at the periphery grooves 6 interrupted. In this way, the effective surface is further increased and thus the heat transfer is further improved.

LIST OF REFERENCE NUMBERS

1

termination element

2

Rejuvenated area

3

Probe

4

shaft

5

Mikroverpressung

6

grooves

7

leads

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

• US 2611791 [0005]
• US 6059453 [0006]
• DE 10238628 B4 [0007]
• DE 102008029227 A1 [0008]
• DE 102008029227 [0010]

Claims (10)

Temperature sensor for measuring high temperatures of gaseous and liquid media with a temperature-dependent measuring element and a metallic socket part, wherein the socket part is connected to process connection components and the lower end of the socket part as a jacket ( 4 ) is formed and projects into the medium to be measured and inside the socket part inner conductor wires ( 7 ), which connect the measuring element to an electrical connection, characterized in that the jacket ( 4 ) is provided in the region in which the temperature-dependent measuring element is arranged, with a micro-compression, wherein the micro-compression of longitudinal grooves or lamellae which extend parallel to the protective tube axis. Temperature sensor according to claim 1, characterized in that the jacket has recesses in the form of rings. Temperature sensor according to claim 2, characterized in that the grooves in the region of the slats or the longitudinal grooves are arranged. Temperature sensor according to one of the preceding claims, characterized in that the height of the fins or the depth of the longitudinal grooves 50 microns to 500 microns, preferably 100 microns to 300 microns. Temperature sensor according to one of the preceding claims, characterized in that the height of the slats or the depth of the longitudinal grooves is less than the distance of the respective adjacent slats or longitudinal grooves. Temperature sensor according to one of the preceding claims, characterized in that the jacket ( 4 ) in the area in which the micro-compression ( 5 ) is arranged, is tapered. Temperature sensor according to one of the preceding claims, characterized in that the medium facing the end of the jacket ( 4 ), at which the micro-compression ( 5 ), a conical or spherical cap-shaped closing element ( 1 ) having. Temperature sensor according to one of the preceding claims, characterized in that the micro-compression ( 5 ) with a thin coating ( 12 ) is provided from a dirt-repellent and high-temperature-stable material. Temperature sensor according to one of the preceding claims, characterized in that the coating has a thickness of 10 ... 20 nm. Temperature sensor according to one of the preceding claims, characterized in that the micro-compression ( 5 ) has a color which has a high reflectance at high temperatures.

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