Temperature measurement with a Handset

Temperature measurement is a large field that includes a variety of measurement situations with different materials, temperature ranges, mass, textures, accuracy and response time required, etc. Therefore, it is difficult to generally indicate when a measurement method works good or bad. For “continuous monitoring” it is common to mount a fixed sensor in the object to be measured, but temperature measurements for eg. food preparation, cooking or inspection of incoming deliveries of food you need to use a handset (hand thermometer).

Our handset can measure with two different methods:

• Infrared measurement (IR) that are non-contact.
• Stick-in probe or temperature probe to insert into (or at) the target object.

All bodies emit electromagnetic waves, radiation, depending on their temperature. The radiation can be used to measure the temperature without touching the measurement object by using an IR thermometer. There are a few things to consider when taking measurements using an infrared thermometer: If your intention is only to make a comparative measurement where absolute accuracy is not so important, it is OK to use an infrared instruments. It is a relatively easy and simple measurement procedure. Some rules of thumb exist in the field of infrared temperature measurements: In general it is possible to make good measurements on all non-metal materials and painted metal surfaces. When it comes to high gloss metal surfaces is not recommended infrared measurement, only if the surface is painted or covered with tape.

Making a measurement with IR:

• Let the thermometer acclimate. To avoid erroneous measurements, the thermometer should stay about 20 – 30 minutes in the temperature at which measurements are to be made. To make a measurement inside a cold room, you need to store the infrared thermometer in there for a while in advance.
• Aim for the target object and press the IR button. Consider the relationship between the distance – measuring range.

Possible sources of error in infrared measurement:

• Bare metal surface. The reflection affects the measurement more than the radiation does.
• The target area is larger than the measurement object.
• Dirt or condensation on the lens.
• Large temperature difference between the instrument and the ambient air
• Air pocket between the packaging and the measured object

If the temperature measurement with IR takes a long time (or becomes unreasonable / wrong), it may depend on moving the thermometer from a warm place to a cold place to make a measurement, for example in a cold storage room. The principle of IR measurement is that the IR module allows for a compensation to their surroundings. If the IR body is warm to start with and then cools down, the measurement will compensated for the change in temperature. Which means that the measurement will take longer time and can also cause an error in the measurement. Action – Let the handset stay a while in the measurement environment (acclimatize) and then repeat the measurement.

A more accurate temperature measurement is done by a stick-in temperature probe.

Stick-in temperature measurements:

• Let the temperature probe acclimatize. To avoid erroneous measurements the thermometer should stay about 20 – 30 minutes in the temperature at which measurements are to be made.
• Insert the probe into object to be measured. If the object is frozen, the probe should be put in-between objects because it is not intended for sticking into ice and will probably break if you try it.

If the probe measurement takes unusual long time, it often depends on non-stable temperature. The handset ensures that the temperatures of the measurements does not vary too much. When temperatures vary and is not stable, the handset will continue to make measurements until the values become stable. If the stick-in probe moves in and out at various locations (ie if you do not hold the probe still in exactly the same place), values ​​may vary  and  the handset will not accept the measurement. It may also be that the probe starting temperature was far from the temperature in the object, then it takes more time for the probe to swing to the right temperature. Action – Let the handset stay a while in the measurement environment (acclimatize) and then repeat the measurement.

Generally, one can say that the stick-in probe is a bit slower than IR and the stick-in probe must of course be thoroughly cleaned between measurements, but stick-in probe provides a more accurate and reliable temperature measurement in most cases.

In addition, our CoolGuard Handset can also link the measurements with pre-defined objects in a list on the display, you scroll and select the object (control point) before executing the measurement. The rendered measurements are then stored in the system and is available in your documentation for food safety.