WO2000042404A1 - Method for stabilisation of electrical resistance of platinum wires - Google Patents
Method for stabilisation of electrical resistance of platinum wires Download PDFInfo
- Publication number
- WO2000042404A1 WO2000042404A1 PCT/SK2000/000002 SK0000002W WO0042404A1 WO 2000042404 A1 WO2000042404 A1 WO 2000042404A1 SK 0000002 W SK0000002 W SK 0000002W WO 0042404 A1 WO0042404 A1 WO 0042404A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- temperature
- wires
- annealing
- platinum wires
- resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
- H01C17/30—Apparatus or processes specially adapted for manufacturing resistors adapted for baking
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C3/00—Non-adjustable metal resistors made of wire or ribbon, e.g. coiled, woven or formed as grids
Definitions
- the invention concerns to method for stabilisation of electrical resistance of platinum wires for resistance thermometers which are used for realisation temperature scale and precise measuring of temperatures up to 1100°C.
- Basis of the invention consists of determination appropriate thermal treatments for fabricated platinum wires - sensors that consist of recrystallisation annealing in a furnace with defined temperature gradient and stabilisation annealing after spooling on skelet of sensors before their mounting to the protecting tube of resistance thermometer.
- the platinum wires are annealed at temperature 1500 to 1750°C under argon atmosphere in a temperature gradient of 21°C/mm to 28°C/mm. During annealing the wires are moved from the region with the highest temperature to the temperature of 20°C and after that they are subjected to isothermal annealing at temperature of 1300°C to 1450°C.
- Such recrystallisation annealed platinum wires will be characterised by stable structure and stable long-term resistance characteristics up to a temperature of 1100°C.
- Fig. 1 shows schematic arrangement of the apparatus for recrystallisation annealing of platinum wires.
- the platinum wires for resistance thermometer with required length will be subjected to annealing in a furnace with defined temperature gradient.
- Modified vertical apparatus consisting of resistance heating elements 1, copper chill 2 and withdrawal system is suitable for this purpose.
- the platinum wires 4 are put to vertical tube 3 which is connected with withdrawal mechanism of apparatus. The tube with the wires is adjusted to a defined position in the apparatus that will assure that the lower part of the wires 6 is at the highest temperature and upper part 5 is in the region with the lower temperature of the apparatus.
- annealing temperature which can be chosen from 1500 to 1750°C.
- the withdrawal of specimen starts.
- the wires are moved from the maximum temperature to a copper chill with the temperature of 20°C such a way that the upper part of the wires moves through whole temperature field of apparatus, i.e. from the initial temperature through maximum temperature until the temperature of the chill.
- Withdrawal rate for the annealed platinum wires in the temperature gradient of the furnace is chosen according to growth kinetics of grains in annealed material and significantly depends on initial state of wires.
- the stabilisation annealing can be performed isothermally for 10 hours at temperature 1300°C to 1450°C under protective argon atmosphere. After stabilisation annealing the skelets with spooled wires are mounted to the body of resistance thermometers.
- the invention is dedicated for production primary, secondary and industry high accuracy platinum resistance wires with the resistance stability higher than the accuracy of those used presently. In addition, for manufacture high stability resistance wires for determination resistance scale at higher temperatures.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
The platinum wires with high structural and resistance stability during long-term using at temperatures up to 1100 °C can be obtained by appropriate thermal treatments. The thermal treatments consist of recrystallisation annealing in the apparatus with a temp erature gradient of 21 °C/mm to 28 °C/mm at a maximum temperature in the apparatus of 1500 to 1750 °C under protective argon atmosphere. During recrystallisation annealing the platinum wires are moved at defined withdrawal rate depending on the initial state of material from the region with maximum temperature to a copper chill with a temperature of 20 °C.
Description
METHOD FOR STABILISATION OF ELECTRICAL RESISTANCE OF PLATINUM WIRES
Technical Field
The invention concerns to method for stabilisation of electrical resistance of platinum wires for resistance thermometers which are used for realisation temperature scale and precise measuring of temperatures up to 1100°C.
Background
Nowadays the platinum wires that are used for fabrication of resistance thermometers show a variation of their resistance with time. Such unstable resistance thermometers are unsuitable for high accuracy measurements of temperature that are required for determination of temperature scale by measuring of fix point of temperature scale. Therefore, it is necessary to modify manufacturing process of platinum resistance wires and increase significantly their long-term resistance stability. High stable resistance temperature sensor for precise measuring is described in the patent application PV 3407- 91. This sensor is equipped by sensible element with directional crystalline structure.
Disclosure of the Invention
Basis of the invention consists of determination appropriate thermal treatments for fabricated platinum wires - sensors that consist of recrystallisation annealing in a furnace with defined temperature gradient and stabilisation annealing after spooling on skelet of sensors before their mounting to the protecting tube of resistance thermometer. The platinum wires are annealed at temperature 1500 to 1750°C under argon atmosphere in a temperature gradient of 21°C/mm to 28°C/mm. During annealing the wires are moved from the region with the highest temperature to the temperature of 20°C and after that they are subjected to isothermal annealing at temperature of 1300°C to 1450°C. Such recrystallisation annealed platinum wires will be characterised by stable structure and
stable long-term resistance characteristics up to a temperature of 1100°C.
Examples
The invention is illustrated in Fig. 1 which shows schematic arrangement of the apparatus for recrystallisation annealing of platinum wires. Before mounting on skelet of sensors the platinum wires for resistance thermometer with required length will be subjected to annealing in a furnace with defined temperature gradient. Modified vertical apparatus consisting of resistance heating elements 1, copper chill 2 and withdrawal system is suitable for this purpose. Before annealing the platinum wires 4 are put to vertical tube 3 which is connected with withdrawal mechanism of apparatus. The tube with the wires is adjusted to a defined position in the apparatus that will assure that the lower part of the wires 6 is at the highest temperature and upper part 5 is in the region with the lower temperature of the apparatus. After multiple vacuum degassing the apparatus is filled by protective argon atmosphere and temperature of the apparatus is increased up to annealing temperature which can be chosen from 1500 to 1750°C. After stabilisation on annealing temperature the withdrawal of specimen starts. Then the wires are moved from the maximum temperature to a copper chill with the temperature of 20°C such a way that the upper part of the wires moves through whole temperature field of apparatus, i.e. from the initial temperature through maximum temperature until the temperature of the chill. Withdrawal rate for the annealed platinum wires in the temperature gradient of the furnace is chosen according to growth kinetics of grains in annealed material and significantly depends on initial state of wires. For commercially produced platinum wires is recommended to use .annealing apparatus with a maximum annealing temperature of 1700°C, copper chill temperature of 20°C and the distance between maximum temperature and copper chill temperature of 60 mm. In such annealed wires, an average length of recrystallised grains is about 0.7 mm to 0.8 mm. This length of recrystallised grains is stable during further annealing at temperatures lower than 1100°C.
In further stage the recrystallisation annealed platinum wires are spooled on skelet of sensors that represent a part of resistance thermometers. After spooling it is necessary to perform stabilisation annealing of the spooled skelets. The stabilisation annealing can be performed isothermally for 10 hours at temperature 1300°C to 1450°C under protective argon atmosphere. After stabilisation annealing the skelets with spooled wires are mounted to the body of resistance thermometers.
The process mentioned above made several platinum wires which were subjected to laboratory tests. The results of laboratory tests show that the resistance wires fabricated according to the invention achieve significantly higher resistance stability in comparison with currently fabricated ones. The achieve results - increase of resistance stability of platinum wires after annealing according to the invention - are shown in Table 1.
Table 1. Resistance stability test of platinum wire
The resistance stability of platinum wires increased by ± 3x10"* K at the triple point of water which is the stability of the used triple of water 273.1600 ± 0.0003 K.
Industrial Applications
The invention is dedicated for production primary, secondary and industry high accuracy platinum resistance wires with the resistance stability higher than the accuracy of those used presently. In addition, for manufacture high stability resistance wires for determination resistance scale at higher temperatures.
Claims
Claims
Method for stabilisation of electrical resistance of platinum wires characterised by their recrystallisation annealing at the temperature 1500°C to 1750°C in the temperature gradient 21°C/mm to 28°C/mm under pure argon atmosphere, during annealing the wires are moved from the region with the highest temperature to a temperature of 20°C and then they are subjected to isothermal annealing at 1300°C to 1450°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU23408/00A AU2340800A (en) | 1999-01-18 | 2000-01-17 | Method for stabilisation of electrical resistance of platinum wires |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SK68-99A SK284764B6 (en) | 1999-01-18 | 1999-01-18 | Method of heat treatment and stabilizing electric resistivity of platinum wires |
| SKPV068-99 | 1999-01-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2000042404A1 true WO2000042404A1 (en) | 2000-07-20 |
Family
ID=20433123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/SK2000/000002 Ceased WO2000042404A1 (en) | 1999-01-18 | 2000-01-17 | Method for stabilisation of electrical resistance of platinum wires |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2340800A (en) |
| SK (1) | SK284764B6 (en) |
| WO (1) | WO2000042404A1 (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0392841A2 (en) * | 1989-04-11 | 1990-10-17 | Industrial Pyrometers (Aust.) Pty. Ltd. | Ceramic coated wires and thermocouples |
| EP0471138A2 (en) * | 1990-08-17 | 1992-02-19 | Heraeus Sensor GmbH | Process for producing an electrical measuring resistor |
| WO1992015101A1 (en) * | 1991-02-15 | 1992-09-03 | Siemens Aktiengesellschaft | High temperature sensor made of metal of the platinum group |
| US5230565A (en) * | 1990-06-06 | 1993-07-27 | Netsushin Co., Ltd. | Pyrometer and a method for fusing an alumina pipe having a high purity |
-
1999
- 1999-01-18 SK SK68-99A patent/SK284764B6/en unknown
-
2000
- 2000-01-17 WO PCT/SK2000/000002 patent/WO2000042404A1/en not_active Ceased
- 2000-01-17 AU AU23408/00A patent/AU2340800A/en not_active Abandoned
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0392841A2 (en) * | 1989-04-11 | 1990-10-17 | Industrial Pyrometers (Aust.) Pty. Ltd. | Ceramic coated wires and thermocouples |
| US5230565A (en) * | 1990-06-06 | 1993-07-27 | Netsushin Co., Ltd. | Pyrometer and a method for fusing an alumina pipe having a high purity |
| EP0471138A2 (en) * | 1990-08-17 | 1992-02-19 | Heraeus Sensor GmbH | Process for producing an electrical measuring resistor |
| WO1992015101A1 (en) * | 1991-02-15 | 1992-09-03 | Siemens Aktiengesellschaft | High temperature sensor made of metal of the platinum group |
Non-Patent Citations (2)
| Title |
|---|
| DATABASE INSPEC [online] INSTITUTE OF ELECTRICAL ENGINEERS, STEVENAGE, GB; BASS N: "Construction of the NBS-design high-temperature platinum resistance thermometer", XP002135985, Database accession no. 2258679 * |
| TECHNIQUES IN HIGH-TEMPERATURE RESISTANCE THERMOMETRY, JAN. 1984, USA, NBS-TN-1183, pages 1 - 7 * |
Also Published As
| Publication number | Publication date |
|---|---|
| SK6899A3 (en) | 2001-05-10 |
| SK284764B6 (en) | 2005-11-03 |
| AU2340800A (en) | 2000-08-01 |
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