DE202008008256U1 - Surface structured temperature sensor - Google Patents

Abstract

temperature sensor for measuring high temperatures gaseous and liquid Media with a temperature-dependent measuring element and a metallic socket part, wherein the socket part with process connection components is connected and the lower end of the socket part as a coat (4) is formed and projects into the medium to be measured and inside of the socket part inner conductor wires (7) extend, the connect the measuring element to an electrical connection, characterized that the jacket (4) in the area in which the temperature-dependent Measuring element is arranged, with a 20 ... 80 microns deep Microstructure is provided.

Description

The 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 Holder part, wherein the socket part with process connection components is connected and the lower end of the socket part as a protective tube is formed and projects into the medium to be measured and inside of the socket part inner conductor wires run, the Connect the measuring element to an electrical connection.

The Invention is for use in technical processes at high temperatures, preferably in exhaust gas temperature strands of high-performance engines or in compressor or diffuser units of gas turbines, suitable.

As temperature sensors measuring resistors or thermocouples can be used. Mostly they are designed as thermocouples. Such temperature sensors are characterized by favorable thermometer dynamics, ie by low T ₅₀ and T _90-time percentage characteristics.

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 further 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 also be covered with insulating silicone.

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

adversely are in the described arrangements in addition to the complex and Thus, cost-intensive production also that only individual the occurring loads is met, so the causes for measurement errors and malfunctions metrological, electrical or mechanical nature are not generally eliminated. In particular, the upper operating temperature limit is not reached, even if the measuring dynamic and static-thermal requirements are fulfilled.

Of the Invention is the object of a device of the initially mentioned type, with the optimal measuring dynamic and static-thermal Properties are achievable even at high operating temperatures. Furthermore, the temperature sensor should allow long service life.

According to the invention the object with a device having the features specified in claim 1 contains, solved.

advantageous Embodiments are specified in the subclaims.

object The invention also feature combinations in which in the Description and / or specified in the claims individual features be combined with each other as desired.

Of the inventive temperature sensor has a metallic shell, which in the region of the temperature sensor provided with a microstructure.

Preferably the microstructure is in the area of the deformed shell part.

The Microstructure can be used as a longitudinal grid parallel to the protective tube axis or be designed as a cross grid.

Further The microstructure can be simple or opposite Be formed screw grid.

The Microstructure preferably has a depth-to-width ratio of 1: 1, at a depth and a width of 20 ... 80 microns with protective tube diameters of 2 ... 4.5 mm. This succeeds, the Heat transfer and thus the response to to improve known arrangements.

As in Wagner: Heat Transfer, Vogel Buchverlag, 5th edition, p. 64 ff , described, change when flowing past a fluid at one Twill the flow conditions in the vicinity of the body and it creates a so-called flow boundary layer. It is advantageous to make the structure depth and / or the structure width of the microstructure smaller than the flow boundary layer of the flowing medium to be formed on the sensor.

expedient it is that attach to the microstructure in the front part of the protective tube a spherical blunt tip connects.

A advantageous embodiment provides that the microstructure provided with a thin additional layer. The additional layer is preferably made of barium nitride or a carbide layer. It prevents corrosion and contamination of the protective tube and thus ensures that the improved response over the life of the temperature sensor is maintained.

Advantageous the additional layer of the microstructure has a layer thickness from 10 ... 20 nm.

Further it is possible that the layer of microstructure a Has relevance to the wavelength of heat radiation, d. H. the color affects in the area of heat radiation the absorption and reflection properties of the protective tube tip.

Especially is the microstructure designed so that the applied color-relevant layer has a high reflectance at high temperatures.

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

The Microstructure can be produced by load technology or microlithography become.

A advantageous embodiment of the invention Method provides that the microstructure by an energy pulse is treated. This can be a cleaning of oxide constituents as well a crack-free surface can be generated.

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.

The Invention will be described below with reference to exemplary embodiments explained in more detail.

In show the accompanying drawings:

1 View and soffit of a version with simple rejuvenation,

2 View and top view of a version with double rejuvenation,

3 a version with coating
and 4 a version with additional protective tube.

In 1 an embodiment with a taper is shown. The side view 1a shows a jacket thermocouple 6 , which at the bottom of a measuring tip 3 having. The measuring tip 3 contains the media-side solder joint of a thermocouple and consists of an anterior taper 2 and the final cone 1 , At the opposite end the free wire ends protrude 7 from the jacket thermocouple 6 out. At the front rejuvenation 2 the diameter of the protective tube was reduced to 2 ... 4.5 mm and with a strip-shaped microstructure 5 Mistake. The microstructure 5 consists of linear depressions with a side-to-depth ratio of 1: 1, the depth and width being 20 ... 80 μm, respectively. In again 1b shown underside, shows the front taper 2 a hexagonal cross-section 10 on. The structure depth and / or the structure width of the microstructure 5 are advantageously formed smaller than the thickness of the flow boundary layer forming on the measuring sensor, in particular smaller than half the thickness of the flow boundary layer.

2 shows an embodiment in which the protective tube 4 is provided with a double rejuvenation. This makes it possible to produce a strong taper cost and with less material stress. The microstructure 5 is at the front rejuvenation 2 attached, like out 2a is apparent. The location of the free wire ends 7 the double inner conductor of the thermocouple is in 2 B shown.

3 shows a temperature sensor, in which the located in the medium part of the jacket 4 with a thin coating 12 is provided. The coating 12 consists of a dirt-repellent, high-temperature-stable additional layer and has a thickness of 10 ... 20 nm. As the coating material, nitride, carbide, boron oxide or a mixture of these substances can be used. With such a coating, a significant increase in the life of measurements in aggressive media and at high temperatures can be achieved. In the example shown, the coating extends 12 on the entire projecting into the medium of the temperature sensor. The attachment to the process takes place with the help of the federal government 11 with a wrap.

In 4 a complete temperature sensor is shown. In this embodiment, the microstructure is 5 on an additional protective tube 9 , which has the shape of a sleeve mounted. The additional protective tube 9 is on the front part of the coat 4 postponed. This design allows a cost-effective mounting of the microstructure. On the coat 4 is the adjustable screw 8th , with which the process connection takes place.

1

degree cone

2

front rejuvenation

3

Probe

4

coat

5

microstructure

6

Sheathed thermocouple

7

free wire ends

8th

adjustable screw

9

Additional protective tube

10

hexagonal deformation

11

Federation with a wrap

12

coating

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• - US 2611791 [0004]
• - US 6059453 [0005]
• - DE 10238628 B4 [0006]

Cited non-patent literature

• - Wagner: Heat Transfer, Vogel Buchverlag, 5th edition, p. 64 et seq. [0017]

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 shell ( 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 20 ... 80 microns deep microstructure. Temperature sensor according to claim 1, characterized in that the structural depth of the microstructure ( 5 ) is less than the thickness of a flow boundary layer forming on the probe. Temperature sensor according to claim 2, characterized in that the structural depth of the microstructure ( 5 ) is less than half the thickness of the flow boundary layer. Temperature sensor according to one of claims 1 to 3, characterized in that the region of the jacket ( 4 ), in which the microstructure ( 5 ) is arranged, is tapered. Temperature sensor according to one of the preceding claims, characterized in that the microstructure ( 5 ) is stripe- or pimple-shaped and has a depth-to-width ratio of 1: 1, with a depth and a width of 20 ... 80 .mu.m. Temperature sensor according to one of the preceding claims, characterized in that on the medium facing part of the jacket ( 4 ) on which the microstructure ( 5 ), a closing cone ( 1 ). Temperature sensor according to one of the preceding claims, characterized in that the microstructure ( 5 ) with a thin coating ( 12 ) is made of a dirt-repellent and high-temperature-stable material of a layer thickness in the range of 10 ... 20 nm. Temperature sensor according to claim 7, characterized in that the coating ( 12 ) consists of nitride, carbide, boron oxide or a mixture of these substances. Temperature sensor according to claim 7, characterized the coating consists of barium nitride. Temperature sensor according to one of the preceding claims, characterized in that the microstructure ( 5 ) has a thermal color which has a high reflectance at high temperatures.