Description
Protecting Sheaths
The thermocouples mentioned above need protection against mechanical injury and chemical attack. Metallic or ceramic protecting sheaths are provided as a cover for the thermocouple element.
Metallic Protecting Sheaths:
These are suitable for uses upto the temperature approximately 1200°C maximum, depending on the particular application. Our standard diameter of these sheaths are 22mm outer diameter (OD) and 3mm wall thickness. Other diameters from 4mm to 52mm outer diameter in various wall thickness are available on request.
Ceramic Protecting Sheaths:
These are suitable beyond 1200°C. Ceramic sheaths are sometimes used as additional covering along with either metallic or ceramic outer sheath for special applications.
Sheath Materials:
| Sheath | Melting Point ºC | Usable Temp. ºC | Characteristics |
| SS-304 | 1400 | 900 | High Resistance to heat and corrosion. |
| SS-316 | 1400 | 1150 | Excellent resistance to heat, acids and alkalies. |
| SS-310 | 1410 | 1150 | Good oxidation resistance and sulphur atmospheres at low temperature. |
| SS-321 | 1400 | 900 | Excellent resistance to corrosion. |
| HRS-446 | 1400 | 1150 | Good oxidation resistance at elevated temperature & sulphur atmosphere. |
| Inconel 600 | 1410 | 1150 | Excellent oxidation resistance (do not use in sulphur atmosphere) |
| Ceramic 610 | 1600 | Excellent thermal, mechanical, electrical and corrosion resistant. |
| Type | Thermocouple | Calibration | Equipment calibration | Temperature Range ºC |
| K | Chromel-Alumel | IS : 2054 | IPTS–1968 DIN 43710 BS 4937 iv | 0-1200 |
Thermocouple Calibration:
| T | Copper-Constanton | IS : 2056 | IPTS–1968 DIN 43710 | 0-400 |
| BS 4937 v | ||||
| IPTS–1968 | ||||
| J | Iron-Constantan | IS : 2057 | ANSI/MC96 | 0-900 |
| BS 4937iii | ||||
| IPTS–1968 | ||||
| R | Pt 13% Rh-Pt | IS : 2055 | DIN 43710 | 0-1600 |
| BS 4937 ii | ||||
| IPTS–1968 | ||||
| S | Pt 10% Rh-Pt | IS : 2055 | DIN 43710 | 0-1600 |
| BS 4937 i | ||||
| IPTS–1968 | ||||
| B | Pt 30% Rh-Pt 6% Rh | IS : 6270 | DIN IEC B8 | 0-1800 |
| BS 4937 vii |
