The SCORPION® 2 Humidity Sensor is designed to measure the absolute moisture content, of the thermal environment, in both heating and cooling processes. Mechanically the Humidity Sensor is comprised of a high temperature moisture sensor, a low temperature moisture sensor, and a bulk air or dry bulb temperature sensor. The moisture sensors are located inside small-insulated chambers, which receive samples of the environment’s air via an axial fan drawing air through precision openings on the front of the device. Both sensor elements are analog capacitive devices, which produce a voltage output linearly related to the moisture content of the sampled air. The High Temperature Sensor “A” is mounted on a solid-state heating system to resist condensation in high humidity environments. The Low Temperature Sensor “B” is maintained at room temperature via a heat sink and surrounding insulation. The Humidity Sensor travels through the process with the product, yielding a precise profile of moisture experienced by the product.
Why is Humidity Profiling important?
Product passing through a thermal process interacts with the amount of moisture in the environment. This moisture often comes from the product itself and represents a delicate balance affecting finished product quality in many ways.
- The amount of moisture left in a pretzel can determine its shelf life.
- Reduced evaporation can keep the surface of a cookie moist, allowing it to stretch, preventing cracks.
- Some products require surface condensation to produce a concentrated sugar solution, which gives the surface a glaze.
- Finished product moisture can directly affect breakage during the packaging process.
Product throughput kg/hr (lb/hr) can also be affected by when and how much moisture builds in a process. Moisture laden environments reduce baking efficiency, thereby reducing product throughput.
Analyzing the Results
In high temperature applications above 100°C (212°F), the output from Sensor A is used and displayed as humidity mass ratio in kg water /kg dry air (lb water / lb dry air). In low temperature applications below 100°C (212°F), the output from Sensor B is used and displayed as % relative humidity. In both high and low temperature applications, the dew point temperature and dry bulb air temperature can be displayed. In Ovens, the Humidity Sensor can be used to document the relationship between oven moisture and finished product moisture. In Cooling Tunnels it can be used to monitor dew point temperature, preventing condensation on the product surface.
- Output from Sensor A is used and displayed as humidity mass ratio in kg water/kg dry air (lb water/lb dry air).
- Sensor documents the relationship between oven moisture and finished product moisture.
- Output from Sensor B is used and displayed as % relative humidity.
- Sensor monitors dew point temperature preventing condensation on the product surface.
Some applications may require additional thermal protection offered by the Humidity Sensor Thermal Barriers.
Problem: A pretzel company has two similar production lines baking pretzel products. One oven bakes more efficiently than the other, consistently producing more pounds per hour… Click the case study link above to see how Humidity Profiling helped solve this problem.