Accurate Calibration of Sanitary Sensors

Food Industry
The pharmaceutical and food industries have strict regulations for the manufacturing processes of their products. Even the smallest change in temperature, for example, can drastically affect the foods or pharmaceuticals produced, putting the health and safety of your customers at risk. 

To ensure that your sensors measure temperature, pressure and humidity accurately they need to be calibrated to exact requirements. By using the right instrument, the short and sanitary temperature sensors needed in the food and pharmaceutical industries (once considered difficult to work with due to their awkward design) can be calibrated accurately. 

Calibration is Key in the Food and Pharma Industries 

The food and pharmaceutical industries both manufacture products that can directly influence human health and safety. Small increases in temperature can make the difference between fresh and spoiled produce, or can result in the active pharmaceutical ingredient (API) being corrupted.  

This means that the processes used to produce food and pharmaceuticals must be controlled and maintained under rigid conditions to ensure consumer safety and a high product quality. 

To ensure these conditions stay at acceptable levels, your temperature, pressure and humidity sensors must be calibrated often to ensure correct readings are taken. Temperature sensors, in particular, are vulnerable, since they can be affected by vibrations and turbulent flow, nearby machinery and air conditioning. They’re also one of the most important types of sensors in the food and pharma industries for determining quality, hygiene and safety.

Sanitary SensorsShort, Sanitary Sensors Are Difficult to Calibrate
Sensors in the food and pharma industries must be designed to meet strict sanitary requirements. This means that they must be clean, and contamination must be held at an absolute minimum. 

Often called short sensors, their design reflects this need for sanitation. However, this design also means that it is awkward to calibrate the sensors accurately. Why? As the name suggests, the sensors are short. And they also consist of a metal flange that causes heat loss, meaning the temperature of the sensing element is different to the temperature of the process which can result in inaccurate readings. 

These temperature errors need to be taken very seriously by everyone. Failing to take them into account, and failure to accurately calibrate your sensors, can mean facing risks. These risks include:

Non-compliance with FDA regulations – food and pharma are heavily regulated, and non-compliance can mean shutting down a process line, or even your company.
Lower traceability – you have to be able to prove to auditors and inspectors that your equipment is accurate. Inconsistent sensor readings prevent this. 
Failing to meet ISO 9001 certification – calibration is an important part of ISO 9001 guidelines.
Lack of quality assurance – inconsistent sensor readings will guarantee uncertainty in the quality of your food or pharmaceutical products.
An increased cost of production – inaccurate sensor readings can mean having to repeat procedures and throw out “bad batches”, therefore raising your operating costs.
More waste – finally, more waste and pollution is a direct result of inefficient calibration of your sensors, because it means repeating processes and dumping “bad batches”. Your company’s carbon footprint will also increase.

As you can see, many problems and risks are associated with inaccurate sensors, and failing to calibrate them properly. But, because calibrating these temperature sensors is tedious (due to their design), finding a calibration unit to do the job isn’t easy.

What Are the Ideal Features of a Sanitary Sensor Calibration Unit? 
It’s challenging to calibrate short sensors when their geometrical design gets in the way. However, the task can be made far easier by using the right calibrator unit. 

Ideally, you’ll want to use a dry-block unit. Liquid baths should be avoided, because they need a bath type where the liquid is pumped to ensure temperature homogeneity all the way to the surface. Also, there’s often a need for "pure" calibration, which means the sensor cannot be contaminated with silicone oil, or anything else located in the bath. 

Traditional dry-blocks are also inadequate, because the sensor needs to be inserted in a debt which equals 15 times its diameter for accurate calibration. So the sensor’s active part must be placed in a zone with homogenous temperature. If this can’t be done, you need to use other methods for accurate sensor calibration.

Here are some considerations to keep in mind, when choosing a calibration unit for short, sanitary sensors: 
The ideal unit will allow you to quickly calibrate short and sanitary sensors using a dry-block calibrator, thus saving you time. 
Calibration should be clean and contamination-free. This means avoiding pollution of the sensor-under-test from calibration oils.
High accuracy is obviously critical, so the unit will need to minimize any uncertainties in measurement.
Customized inserts should be available to promote optimal heat transfer around the sensor being calibrated.
Easy-to-use calibration software is important for minimizing errors and delay.

Bottom line: The right calibration unit can save you time and hassle, and help you to make sure your sensors are reading accurately. 

This means you’ll comply with FDA and ISO 9001 regulations, minimize waste and risk, lower costs, and ensure quality in any food or pharmaceutical manufacturing process.

How Can You Calibrate Your Sanitary Sensors?
Remember: temperature sensors should be checked for accuracy regularly. Calibration should be done at least once a year, and the details including date and time stored with the instrument

The RTC-156B from AMETEK has been designed to take away the difficulties and inaccuracies associated with calibrating the short sensors used in the food and pharmaceutical industries. 

Now, you can avoid cumbersome and time-consuming liquid-bath calibrations, and the performance issues associated with older dry-block units.

The RTC-156B can calibrate short, sanitary temperature sensors with awkward designs. It employs dual-zone technology to maintain full control of the temperature in the lower part, as well as in the upper part of the heating block. This enables the unit to compensate for the extreme heat dissipation through the flange of the sanitary sensor. Meaning calibration remains accurate in spite of the sensors awkward designs and your sensors will stand up to FDA and ISO 9001 inspections. 

Inserts with reference sensorA special insert with a large mechanical contact face at the top ensures optimal contact with the sensor. A small special designed reference sensor shall sit parallel with the sanitary sensor. The reference sensor can accurately measure the insert temperature adjacent to itself and the sanitary sensor. 

In addition to its excellent specifications and accuracy the RTC-156B is designed for ease of use. Plug and play operation, a simple and intuitive user-interface and easy to read data all make sensor calibration as straightforward and simple as possible.  

Gone are the days of worrying about if your sensors are calibrated accurately or struggling to use and old and out-of-date machine. The RTC-156B is an accurate, fast, and easy way to calibrate your sanitary temperature sensors that ensures you’ll save time, money and stress in your food and pharmaceutical manufacturing processes. 

More in-depth technical information on optimizing your sanitary sensor calibration using dry-block technology, including results and a demonstration of the reduced error of measurement, is available in our white paper section.