Temperature sensor protection well, general types
We offer tailor-made temperature sensors / transmitters for diesel engines and related marine and industrial applications. Our range of sensors includes resistance (Pt100/Pt1000), thermocouple (NiCr/NiAl), thermistor elements (NTC), and our unique wireless temperature sensors based on a Surface Acoustic Wave (SAW) elements.
Control and traceability
All temperature sensors we deliver are controlled to fulfil their specifications, normally according to tolerance given by IEC. If desired by the customer, a certificate can be supplied with each sensor. Our calibration department maintains instruments used for production control. The calibration equipment is regularly checked by comparison with our factory standard, which again is traceable to national and international temperature standards according to ITS90. (ITS90 = The International Temperature Scale of 1990).
Response time of a temperature sensor
The response time of a temperature sensor is expressed by the time constant T. If a temperature sensor with temperature T1 is immersed in a liquid at temperature T2, T is the time it takes before the temperature sensor has reached 1 - 1/e ~ 0.63 = 63 % of the temperature difference T2-T1. After the time 2.3T, 90 % of the temperature difference is reached, and after 5T the sensor will show more than 99 % of the difference. If the sensor is mounted in a protection well, the time constant will be approximately doubled. To reduce the time constant, it is recommended to apply heat transfer compound between sensor and protection well. When compound is used, the time constant will decrease by about 30 %.