Temperature Meter

Temperature plays an important role for human well-being and in the course of many biological, physical and chemical processes. The reliability of many electronic devices is also only guaranteed for certain temperature ranges. Compliance with the desired temperature can be easily monitored with a temperature measuring device. With some of these thermometers, the measured values can be recorded or passed on directly to control and regulation devices. Depending on the intended use, the most suitable temperature measuring device can be selected in terms of design, handling, operating principle and accuracy.

In order to find the right temperature measuring instrument from the multitude of available thermometers, you can narrow down the choice by considering a few basic criteria.

- Which maximum and minimum temperatures must the temperature measuring instrument be able to record?
- What accuracy must the thermometer have in the desired measuring range?
- Should the temperature be measured on surfaces, in gases (e.g. air temperature), in liquids, in solids or bulk solids?
- Is a contactless measurement possible and useful?
- Should the temperature measuring instrument measure and record the data continuously?

A temperature measuring instrument with an analogue display can be very simply constructed. Everyone probably still knows the liquid thermometers for displaying the outside temperature, for room temperature, for measuring fever and for checking the bath water temperature. Such a thermometer works without batteries and shows the temperature on a line scale. If the liquid expands as the temperature rises, it goes up and reaches the mark on the case corresponding to the higher temperature. If the temperature drops, the liquid goes down again to the lower position on the display.

Another analogue temperature measuring instrument uses the different temperature expansion of two different metals. The change in length when the temperature changes, causes the bimetallic strip to bend and the pointer position of the analogue display to change.

In a digital temperature measuring instrument, the measurement and display of the temperature can happen separately. The measurement data can be easily stored and processed in the digital temperature measuring device. There are many digital thermometers in which various temperature sensors can be connected to the display unit. Laser sensors are not interchangeable. However, a temperature measuring instrument with a laser sensor can have an additional internal sensor for the air temperature and one or more connections for other temperature sensors. These sensors for the temperature measuring device can differ in the temperature measuring range, size and shape and in the measuring principle. Among the most common measuring principles of the interchangeable sensors are the thermocouples and platinum resistance sensors, especially PT-100 and PT-1000. By exchanging the sensor it is possible to test very different measuring points with the same temperature measuring device.

A temperature data logger is always a digital temperature measuring device. The storage interval is set via the device menu or associated PC software and after the measuring period has been over, the data is read out from the temperature measuring device. Some long-term data loggers are equipped with the analog inputs and can be set in such a way that the storage of the measurement data is only started or stopped when a specified value has been reached. Often the software belonging to the temperature measuring instrument allows different graphical and tabular representations of the measured data.

A multi-channel temperature measuring instrument can display and store the data from several sensors simultaneously. The connections on the display device can be designed for temperature sensors of the same type or for different types of sensors. With the multi-channel temperature measuring device, the temperatures can be measured and evaluated simultaneously at several points during one process.

Temperature measuring device for lounges
For living and working spaces, there are temperature specifications for the minimum temperature not only because of the temperature requirements of the users, but also to prevent the damage from moisture. Moisture damage can occur when warm air hits cold surfaces, cools down and some water vapor becomes condensation. Not only the air temperature, but also the surface temperature of the room's boundary surfaces and the air humidity play a role in the perception of temperature. If the temperature measuring instrument has an additional sensor for air humidity, it is also called a thermo-hygrometer. The dew point temperature valid for this air humidity can be determined from the relative air humidity and the temperature. This is the temperature at which the air can still absorb the existing amount of water as vapor. If the temperature drops further, part of the water vapour becomes liquid. Many thermos-hygrometers can show the dew point temperature directly on the display. If you choose the temperature measuring instrument with an additional temperature sensor for surface measurements, you can easily measure the temperature on external components with constructive or geometric thermal bridges and compare it with the displayed dew point temperature. For such measurements it is very easy to use the temperature measuring device in which an additional sensor for surface temperature measurement work via infrared radiation, as this allows fast and contact-free measurement even over long distances. The temperature measuring device that is only intended to control the room temperature can be read directly by the room users as a simple table or wall device. If the values are outside the desired range, the room can be ventilated, heated or cooled as required. If the temperature and, if necessary, also the humidity are to be monitored and evaluated over longer periods of time, the devices are used which store this data at fixed intervals.

Temperature measuring device for storage rooms and transport
For the shelf life of many foodstuffs and also for some other materials, maintaining certain temperatures is of immense importance. Food warehouses and in particular cold stores for perishable goods of high value should be monitored in such a way that if the temperature rises to an impermissible level, countermeasures can be taken in good time or the goods can be used before they spoil. The temperature measuring device, for example, which can issue an optical or acoustic alarm at the monitored point when the set critical temperature value is reached or send the data to a control system, is suitable for monitoring purposes.

Data loggers are suitable for verifying that the required temperatures are maintained during the transport of goods. A data logger is any temperature measuring device that measures and stores the temperature at fixed intervals. This temperature measuring device can be placed inconspicuously between the goods or even inside the outer packaging. If the goods were not monitored during the transport, the temperature can be checked at least on delivery. For this purpose, the core temperature of various random samples can also be measured using suitable insertion thermometers.

Temperature measurement in processes with heat input
For many products, the maintenance of the certain temperatures during the manufacturing process over a specified period of time is provided by the temperature measuring device. This is important, for example, in yoghurt production, during homogenization, when cooking food, when drying sensitive materials and during sterilization or pest control using heat. If the temperature measuring instrument can transmit the set limit values as a signal, the process heat can be controlled via this. If the temperature measuring device gives the signal at minimum or maximum temperature, the heat input can be automatically increased or decreased.