Non Contact Temperature Sensors

• A thermal image (Thermogram) is a digital representation of a scene and a measure of the thermal radiation emitted by the pictured objects. Thermal images are captured via thermographic cameras (Thermal Imagers), which are devices capable of sensing this radiation in the form of infrared light.
• A thermal image allows us to remotely sense the temperature of an object or at least accurately tell its temperature relative to its environment. This is useful as it allows us to essentially “see” in the dark as well as perceive the temperatures of many objects remotely.

• Thermal camera uses special sensor to measure the Infra Red energy emitting from any body. As every object in the universe with temperature above Absolute zero -273.15°C emits IR, This can be used to measure temperature of that particular object

• Thermal camera is not used to detect the virus, but the Thermal camera measures the temperature of a person’s face and let us know if that person is suffering from fever or not. As Fever is a symptom for the virus, that person can be isolated and sent for further medical diagnosis.

• No Thermal Imaging camera works on the Infra Red spectrum, and it will only see through objects which are transparent in IR range like Germanium, ZnSe etc. A brick wall will not be transparent and hence thermal cameras cannot see through walls.

A Pyrometer is a non-contacting device that intercepts and measures thermal radiations, without making any contact with the radiating body and the process is known as Pyrometry. This device is useful for determining the temperature of an object’s surface.

Pyrometer strictly works on the principle of black body radiation. Here emissivity of the target plays an important role, as it governs how bright the target appears to the pyrometer. Due to its high accuracy, speed, economy and specific advantages, it is widely being used as a standard procedure in many industrial applications.

Working:

• An optical system gathers the visible and infrared energy from an object and focuses it to the detector.
• The detector receives the photon energy from the optical system and converts it to an electric signal to drive a temperature display or control unit.

• Temperature Range:
  Basic requirement to choose a pyrometer is to know the temperature range of the application.
• Spectral range:
  The material of the measured object demands the correct selection of spectral range of pyrometer.
• Field of View (D: S ratio):
  The larger the measuring distance/spot size (D:S) ratio, the higher the optical resolution. The spot size has to be as big as the measured object to achieve a correct temperature measurement.
• Sighting:
  For easy focusing of pyrometers to measure object, different sighting system are available i.e. aiming and View finder.
• Records of the data:
  Data logging and companion software for data storage, retrieval and analysis.
• Calibration of Pyrometer:
  A Pyrometer should be calibrated at desired temperature ranges.

• Ability to monitor temperature in situations where the object is inaccessible or moving.
• Where the object may be contaminated or damaged by a contact sensor.
• Where contact is not possible due to extremely high temperatures, or where the object is electrically active.
• An Infrared Thermometer can be mounted remotely from the hot target, enabling it to operate for long periods with minimal maintenance.
• Lightweight, User Friendly and Compact.
• Very fast response time in tune of msec.

Pyrometers have wide range of diverse applications in various industries:

• Glass Industries
• Steel Industry
• Cement Industries
• Power Industries
• Non-Ferrous Industries