Thermocouples measurement range

Many industrial processes require temperature statements reliable and regular. THE Thermocouple sensor meets this need by measuring Large temperature beaches in various environments. There is 8 main types of thermocouple, each dedicated to a specific measurement range. To deepen the subject of Thermocouples measurement range And help you choose your sensors, we will come back to the Thermocouple operation. We will then see all of its characteristics.

The principle of the thermocouple sensor

THE Thermocouple sensor is a component of the Thermocouple probe, A temperature measurement device. Its operation is based on theSeebeck effect, that is to say that a electrical voltage Can be noted when exposed to a temperature change. This voltage is then converted to ° C or in ° F via the Thermocouples conversion tables.

THE thermocouple contains two metal sons Drivers connected at a point and forming an open loop. There Electro-motor force (FEM) Appears when the welding connecting the two wires is placed in the medium whose temperature is desired. The other ends of the wires make it possible to link to themeasuring device. We call these points cold welds. The conversion tables consider that the cold point is at 0 ° C or 32 ° F. If this temperature varies, a compensation must be carried out.

The large thermocouple measurement range

He is the temperature sensor The most commonly used in the industry. He is robust, offer a good Vibration resistance and a measurement satisfactory. Her cost is weak and it provides a quick response Faced with temperature changes.

He can measure extreme temperatures, both very low and very high. Well chosen, it allows you to raise temperatures with a high precision and a Minimal response time. Thermocouple is a contact probe, which can measure a room temperature like a surface temperature.

What determines the measurement range of a thermocouple?

There measurement range designates thetemperature amplitude than a thermocouple can measure. Also called measurement range, it varies depending on Thermocouple type. We talk about 8 types of thermocouples Because they are the most used and compatible with the CEI 60584.1 standard.

Besides materials and measurement beaches, another key element is the conversion curve. This curve indicates the temperature corresponding to the electromotive force Raised by the instrument. The temperature is in abscissa and the ordered millivolts.

The thermocouples measurement beaches by type

Kind K (Chromel / alumel): 0 to 1100 ° C in continuous use, -200 to 1300 ° C in intermittent use.
Kind J (Iron / Constantan): -20 to 700 ° C in continuous use, -180 to 750 ° C in intermittent use.
Kind T (Copper / Constantan): -185 to 300 ° C in continuous use, -250 to 400 ° C in intermittent use.
Kind E (Chromel / Constantan): 0 to 800 ° C in continuous use, -40 to 900 ° C in intermittent use.
Kind N (Nicrosil / Nisil): 0 to 1150 ° C in continuous use, -270 to 1280 ° C in intermittent use.
Kind S (Rhodied platinum 10 % / Platinum): 0 to 1550 ° C in continuous use, 0 to 1700 ° C in intermittent use.
Kind R (Rhodied platinum 13 % / Platinum): 0 to 1600 ° C in continuous use, 0 to 1700 ° C in intermittent use.
Kind B (Rhodied platinum 30 % / Rhodié platinum 6 %): 100 to 1600 ° C in continuous use, 0 to 1800 ° C in intermittent use.

Understand the thermocouple measurement range to choose a probe

The choice of a thermocouple depends on the technical requirements of the project. We must align the measurement range thermocouple with the measurement temperature.

Each type of thermocouple has a continuous beach and a Intermittent range of use. The first must be favored to avoid altering the Thermal probe. Using a continuous probe on its intermittent beach can reduce its lifespan and distort the readings.

Determine measurement temperature also allows you to choose the Associated tools, as a recorder. This device, equipped with a digital display, stores temperature data and can manage several thermocouples simultaneously.