Nota de aplicación

Dew Point in Industrial Drying

Why industrial drying — such as spray drying — seeks the right balance between product quality and energy consumption, and why different technology is needed to measure relative humidity and dew point in very dry air.

Industrial drying — dairy and food spray drying, process ovens, paint booths — depends on a precise balance between the drying air's humidity and the final product's. For the general context of this magnitude, see the humidity instrumentation landing.

Over-drying wastes energy; under-drying compromises microbiological safety and product quality. That balance only holds with reliable humidity measurement at different points in the process.

This note covers

Why industrial drying seeks the right balance between quality and energy consumption
What variables are controlled during a drying process — beyond relative humidity
Why HUMICAP® and DRYCAP® cover different humidity ranges within the same process

The Balance Between Quality and Energy

Proper drying prevents microbial growth and keeps the product safe for consumption — that's the non-negotiable floor. But from there, the goal becomes minimizing energy use without sacrificing quality: the key is to increase input volume or humidity levels just enough to minimize energy usage, but not so much that end-product quality suffers.

That fine-tuning is only possible if humidity measurement in the drying air and the product itself is accurate enough to operate close to the limit, instead of leaving a wide safety margin that wastes energy.

What Variables Are Controlled During Drying

A well-instrumented industrial drying process monitors several related parameters: the product's sticky point, the adsorption isotherm, the glass transition point (Tg), exhaust air relative humidity, and dew point in the drier zones of the process.

Each of these parameters defines a different operating limit — a single generic ambient humidity reading isn't enough to make real-time process decisions.

Why HUMICAP® and DRYCAP® Cover Different Ranges

Vaisala's HUMICAP® technology delivers the stable, accurate relative humidity measurement needed to develop cost- and energy-efficient manufacturing processes, in the stretches of the process where humidity stays within moderate-to-high ranges.

In the very dry air zones — where dew point rather than relative humidity needs to be measured, or trace residual moisture — Vaisala uses DRYCAP® technology, specialized in low-humidity and dew point applications. Combining both technologies at the right points in the process is what allows energy consumption to drop without losing consistency in product quality.

This technical content is based on Vaisala's documentation on industrial drying and spray drying process monitoring. AKRIBIS is an authorized Vaisala partner for distribution and technical support in the region — explore the full Vaisala instrumentation line. For the specific probe for your drying process, consult a specialist.

Instruments to Measure Humidity