GB2257794A - Electric thermometer with pressure- and corrosion-proof measurement transmission - Google Patents
Electric thermometer with pressure- and corrosion-proof measurement transmission Download PDFInfo
- Publication number
- GB2257794A GB2257794A GB9214759A GB9214759A GB2257794A GB 2257794 A GB2257794 A GB 2257794A GB 9214759 A GB9214759 A GB 9214759A GB 9214759 A GB9214759 A GB 9214759A GB 2257794 A GB2257794 A GB 2257794A
- Authority
- GB
- United Kingdom
- Prior art keywords
- electric
- measuring
- bushing
- thermometer according
- electric thermometer
- 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.)
- Granted
Links
- 230000005540 biological transmission Effects 0.000 title description 2
- 238000005259 measurement Methods 0.000 title 1
- 239000011521 glass Substances 0.000 claims description 23
- 230000001681 protective effect Effects 0.000 claims description 18
- 230000007797 corrosion Effects 0.000 claims description 6
- 238000005260 corrosion Methods 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 238000003889 chemical engineering Methods 0.000 claims description 4
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 claims description 3
- 229920003023 plastic Polymers 0.000 claims description 3
- 239000004033 plastic Substances 0.000 claims description 3
- 229920005989 resin Polymers 0.000 claims description 3
- 239000011347 resin Substances 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 3
- 239000012811 non-conductive material Substances 0.000 claims description 2
- 238000007789 sealing Methods 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000012429 reaction media Substances 0.000 description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 239000005388 borosilicate glass Substances 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 101150039167 Bex3 gene Proteins 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000009760 functional impairment Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 150000003057 platinum Chemical class 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/08—Protective devices, e.g. casings
- G01K1/10—Protective devices, e.g. casings for preventing chemical attack
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Measuring Fluid Pressure (AREA)
- Glass Compositions (AREA)
Description
Electric thermometer with neasurenent transmission Description -pressure-
and corrosion-Droof The invention relates to an electric thermometer for chemical engineering, having an electric temperature sensor in a thickwalled, glass protective tube, which is closed at its front measuring end, and an electric terminal housing for the 10 connecting wires of the temperature sensor.
The regulations governing explosion-proof operating material L L- such as, in particular, elec ric thermometers require safety separation of the electric neasuring circuits from the explosive medium. in the case of thermometers, this is achieved by neans of reliable pro-tective tubes, which are i-.ade from acceptably corrosion-resistant materials with specific minimum wall thicknesses in a suitable pressure-, heat- and vibration-resistant form.
In chemical engineering, for reasons of corrosion resistance, so-called glass thermometers nade of highly chemically resistant borosilicate glass are used. They comprise a thickwalled glass tube tapered and closed at itS front end to form a measuring tip. The temperature sensor is disposed inside the measuring tip.
The temperature sensor may take the form of a platinum resistance thermometer or a thermocouple. Its electric connecting wires are led out through the glass tube to the rear open end of the tube and fastened to the terminals of an electric terminal housing. Said terminal housing is usually cemented onto the rear end of the protective tube using a suitable synthetic-resin adhesive. In order to fasten said thermometer onto the connection fitting of the chemical reaction vessels, a glass sleeve, whose internal diameter is nuch greater than the external diameter of the protective tube, 1 -3 is slipped over the shaft of the protective tube. The rear end of the glass sleeve facing towards the terminal housing is permanently fused with the protective tube, while the front end is provided with a standard glass flanged joint according to DIN ISO 3587 for fastening to the corresponding connection fitting of the reaction vessels. The sealing surfaces of the flanged joint may be spherical or plane. To seal of f the corrosive media in the reaction vessels from the outside environment, a sealing ring made of suitable material is placed between the sealing surfaces.
In the installed state, the measuring tip of the thermometer protrudes into the reaction medium. Heat conducting pastes are used to improve the transfer of heat from the reaction medium to the temperature sensor disposed in the measuring tip. Generally, there are temperatures of up to 2000C and overpressures of up to 4 bar in the reaction vessels. The reaction media are usually pumped through the reaction vessels. During said process, f low rates occur of up to 3 m/s in the case of liquid media and up to 20 m/s in the case of gaseous media.
The prior art thermometers described above, despite the use of highly chemically resistant borosilicate glass in high wall thicknesses, still have one serious safety defect. The interior of the protective tube is namely directly connected to the environment via its open end and via the terminal housing which is sealed of f only in accordance with environmental requirements. In the event of fracture of the measuring tip or the protective tube, the generally very corrosive and/or explosive reaction medium may therefore pass directly into the environment. Fracture of the glass tube may occur, for example, if vibrations are induced in the tube as a result of the media flowing past. While such fractures are rare, they do constitute a residual risk which should, if possible, be avoided.
2 The aim of the invention is therefore to provide a thermometer which, in the described operating conditions, reliably prevents an escape of reaction media into the environment, even in the event of fracture of the protective tube.
Said aim is achieved according to the invention by an electric glass thermometer which is characterized in that the rear end of the protective tube and the terminal housing are connected to one another by a flanged joint and the protective tube is sealed off in a pressure- and corrosion-proof manner by an electric measuring bushing inserted between the two flanges.
It is particularly advantageous if the measuring bushing is provided with an integrated collar, which is clampable between the flanges. To improve compression strength, the measuring bushing is advantageously supported at its end remote from the sensor by the rear flange. This may be effected by making the internal diameter of the rear flange smaller than the external diameter of the body of the measuring bushing or by providing the rear flange with a diametrically disposed web for supporting the measuring bushing.
For centering the measuring bushing in the two flanges, a centering device in contact with the exterior of the f lange may be used which, in a simple manner, may comprise a plastic or metal ring slipped externally onto the measuring bushing.
The measuring bushing becomes particularly corrosion-resistant when it is made of a fluorocarbon resin and the electrical connection is established by means of at least one axially directed, electrically conductive through-pin made of corrosion-resistant metal, preferably tantalum. However, depending on the area of application, other materials may be used for the measuring bushing, such as polyethylene or equivalent plastic materials, glass or ceramics for the bushing and tungsten, austenitic steel, noble metals or suitable alloys for the electric through-pins. Materials must be selected 3 which are resistant to the reaction media in question.
It has proved particularly advantageous if the rear flange is made of electrically non-conductive material.
Compared to the one-piece glass thermometers of prior art, the glass thermometer according to the invention fitted with the pressure- and corrosion-proof measuring bushing achieves a substantial increase in operational reliability.
The invention is described in greater detail hereinafter with reference to a specific embodiment. The drawings show:
Figure 1: general view of a glass thermometer according to the invention, Figure 2: detail drawing of the electric measuring bushing, Figure 3: support of the measuring bushing on the rear flange with a small internal diameter, Figure 4: support of the measuring bushing on the rear flange by means of a web, Figure 4a:view according to A - A in Figure 4, Figure 5: measuring bushing with centering.
Example:
Figure I is a view of a- glass thermometer according to the invention. It comprises a thick-walled protective tube (1) made of glass and having at its front end a tapered and hermetically closed measuring tip (2). Disposed in the measuring tip is a platinum resistance thermometer (3) which, for improved thermal contact with the glass wall of the 4 i> measuring tip, is embedded in heat conducting paste.
The rear end of the protective tube is introduced into a thickwalled glass sleeve (4) and internally fused with the glass sleeve. The internal diameter of the glass sleeve is much greater than the external diameter of the protective tube. Both ends of the glass sleeve are designed as glass flanged joints according to DIN ISO 3587. The flanged joint (5) facing towards the measuring tip and having a spherical (alternatively ladle-shaped or plane) sealing surface serves to fasten the thermometer onto the corresponding connection fitting of the reaction vessels, while the second flanged joint (6) serves to connect the thermometer to the corresponding flange (7) on the terminal housing (8). In the present example, the flanged joint (7) is made of metal. Both f langes (6) and (7) have plane sealing surfaces. Spherical and ladle-shaped sealing surfaces are also possible.
To seal off the interior of the thermometer from the external environment, the electric measuring bushing is used, which comprises the bushing body (9) with the integrated collar (10) and metal through-pins (11) which are axially aligned in pairs. For reasons relating to corrosion and heat resistance, the bushing body with the collar is made of a fluorocarbon resin and the through-pins are made of tantalum.
The two flanged joints (6) and (7), with the collar of the measuring bushing disposed therebetween, are held together by means of a standard connection flange (12). In the present example, the collar also performs the function of a seal.
The connecting wires (13) of the resistance thermometer are run from the measuring tip rearward through the protective tube and are electrically connected to the measuring bushing. on the other side of the measuring bushing, corresponding electric connecting leads lead from the through-pins to the terminals (14) in the terminal housing.
Figure 2 is a detail drawing of the measuring bushing. it comprises the bushing body (9) with collar (10) formed thereon, and two electrically conductive through-pins (11). The collar (10) performs the function of the otherwise required sealing ring for the flanged joint (6) and (7). To optimize the sealing properties, the collar is provided with an annular bead (15).
In the specific embodiment of Figure 2, the collar occupies an end position. Without any functional impairment, the collar may of course alternatively be disposed at any point along the bushing body (9). Nor do the sealing surfaces of the flanged joint (6) and (7) necessarily have to be planear. Spherical sealing surfaces are also possible.
Figure 3 shows an embodiment of the measuring bushing with particularly pressure-proof support of the bushing in the event of fracture of the glass tube. Said support is achieved by the internal diameter of the rear flange (7) being smaller than the external diameter of the body of the measuring bushing. In the embodiment of the measuring bushing of Figure 4, pressure-proof support is achieved by means of a diametrically disposed web (16).
In a further embodiment of the invention shown in Figure 5, the measuring bushing clamped between the two flanges (6) and (7) is centered relative to the flanges by means of a centering ring (17) slipped externally onto the bushing. The convex surface of the centering ring then engages formfittingly over the exterior of the front flange (6), thereby achieving coaxial alignment of measuring bushing and flange.
0 6
Claims (1)
- Patent claims2.3.Electric thermometer for chemical engineering, having an electric temperature sensor in a thick-walled, pressureproof, glass protective tube, which is closed at its front measuring end, and an electric terminal housing for the connecting wires of the temperature sensor, wherein the rear end of the protective tube and the terminal housing are connected to one another by a flanged joint and the protective tube is sealed off in a pressure- and corrosion-proof manner by an electric measuring bushing inserted between the two flanges.Electric thermometer according to claim 1, wherein the measuring bushing is provided with an integrated collar, which is clampable between the flanges.Electric thermometer according to claim 2, wherein the measuring bushing is supported at its end remote from the sensor by the rear flange.Electric thermometer according to claim 3, wherein the internal diameter of the rear flange is smaller than the external diameter of the body of the measuring bushing.5.Electric thermometer according to claim 1, wherein the measuring bushing is clamped between the two flanges and has a centering device in contact with the exterior of the flange.6. Electric thermoneter according to clain, 5, wherein the centering device comprises a plastic or metal ring slipped externally onto the measuring bushing.7.Electric thermometer according to any of claims 1 to 6, wherein the measuring bushing is made of a fluorocarbon 7 resin and has at least one axially directed, electrically conductive through-pin made of a corrosion-resistant metal.8. Electric thermometer according to claim 7, wherein the electric through-pin is made of tantalum.9. Electric thermometer according to any of claims 1 to 8, wherein the rear flange is made of electrically nonconductive material.10. Electric thermometer for chemical engineering substantially as hereinbefore described with reference to the drawings.8
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4123093A DE4123093C2 (en) | 1991-07-12 | 1991-07-12 | Electrical thermometer with pressure and corrosion-resistant measurement |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9214759D0 GB9214759D0 (en) | 1992-08-19 |
| GB2257794A true GB2257794A (en) | 1993-01-20 |
| GB2257794B GB2257794B (en) | 1994-08-03 |
Family
ID=6435987
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9214759A Expired - Fee Related GB2257794B (en) | 1991-07-12 | 1992-07-10 | Electric thermometer with pressure- and corrosion-proof measurement transmission |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE4123093C2 (en) |
| FR (1) | FR2689631B1 (en) |
| GB (1) | GB2257794B (en) |
| IT (1) | IT1257906B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997032188A1 (en) * | 1996-03-01 | 1997-09-04 | Ab Svensk Värmemätning Svm | Temperature sensor |
| US20120051397A1 (en) * | 2010-08-30 | 2012-03-01 | Denso Corporation | Temperature sensor |
| WO2014041168A2 (en) * | 2012-09-17 | 2014-03-20 | Tesona Gmbh & Co.Kg | High temperature sensor with a protective tube in the cold section |
| US9958334B2 (en) | 2012-09-17 | 2018-05-01 | TESONA GmbH & Co. | High temperature sensor with a moulded protective tube |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4344174C2 (en) * | 1993-12-23 | 1999-07-22 | Temperaturmestechnik Geraberg | Temperature sensor |
| DE102010063062A1 (en) | 2010-12-14 | 2012-06-14 | Endress + Hauser Wetzer Gmbh + Co. Kg | Protective tube inner part for a thermometer with a protective tube |
| DE102011089942A1 (en) | 2011-12-27 | 2013-06-27 | Endress + Hauser Wetzer Gmbh + Co. Kg | Receiving device for measuring insert, has mold portion for fastening receiving device to pipeline, where mold portion has bore, in which component is inserted from end of bore |
| DE102012112579A1 (en) | 2012-12-18 | 2014-06-18 | Endress + Hauser Wetzer Gmbh + Co Kg | Receiving device, particularly protective tube, for measuring insert, particularly for determining temperature of measuring material in process container, has two sections, which are separated from each other through passage |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE25975C (en) * | ||||
| DE667417C (en) * | 1935-06-28 | 1938-11-11 | Siemens & Halske Akt Ges | Thermocouple with gas-tight protective tube |
| DE715975C (en) * | 1936-04-21 | 1942-01-10 | Ig Farbenindustrie Ag | Device for introducing thermocouples in high pressure vessels for the pressure hydrogenation of coal and other fuels |
| US2177033A (en) * | 1937-10-12 | 1939-10-24 | John E Buell | Thermocouple tube |
| DE2235676A1 (en) * | 1972-07-20 | 1974-02-07 | Inter Control Koehler Hermann | DEVICE FOR DETERMINING THE TEMPERATURE OF A MEDIUM IN A HOUSING |
| DE2944487A1 (en) * | 1979-11-03 | 1981-05-14 | Robert Bosch Gmbh, 7000 Stuttgart | FAST TEMPERATURE SENSOR FOR AN INTERNAL COMBUSTION ENGINE |
| DE3516815A1 (en) * | 1985-05-10 | 1986-11-13 | Rheinische Braunkohlenwerke AG, 5000 Köln | THERMOCOUPLE FOR A REACTION ROOM OPERATED UNDER INCREASED TEMPERATURE AND PRESSURE |
-
1991
- 1991-07-12 DE DE4123093A patent/DE4123093C2/en not_active Expired - Fee Related
-
1992
- 1992-07-06 FR FR929208323A patent/FR2689631B1/en not_active Expired - Fee Related
- 1992-07-10 GB GB9214759A patent/GB2257794B/en not_active Expired - Fee Related
- 1992-07-10 IT ITTO920590A patent/IT1257906B/en active IP Right Grant
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997032188A1 (en) * | 1996-03-01 | 1997-09-04 | Ab Svensk Värmemätning Svm | Temperature sensor |
| US20120051397A1 (en) * | 2010-08-30 | 2012-03-01 | Denso Corporation | Temperature sensor |
| US9285277B2 (en) * | 2010-08-30 | 2016-03-15 | Denso Corporation | Temperature sensor |
| WO2014041168A2 (en) * | 2012-09-17 | 2014-03-20 | Tesona Gmbh & Co.Kg | High temperature sensor with a protective tube in the cold section |
| WO2014041168A3 (en) * | 2012-09-17 | 2014-07-17 | Tesona Gmbh & Co.Kg | High temperature sensor with a protective tube in the cold section |
| US9958334B2 (en) | 2012-09-17 | 2018-05-01 | TESONA GmbH & Co. | High temperature sensor with a moulded protective tube |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2689631A1 (en) | 1993-10-08 |
| DE4123093A1 (en) | 1993-01-21 |
| FR2689631B1 (en) | 1994-06-10 |
| ITTO920590A0 (en) | 1992-07-10 |
| DE4123093C2 (en) | 1995-06-01 |
| IT1257906B (en) | 1996-02-16 |
| GB2257794B (en) | 1994-08-03 |
| GB9214759D0 (en) | 1992-08-19 |
| ITTO920590A1 (en) | 1994-01-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19980710 |