Special force sensor for pure vapour drying

About the project

Pure vapour drying is a thermal drying process that can be used to gently dry products. It is a process in which the vapour of the product to be dried is used to dry the product without direct contact with the heat source. This results in uniform and gentle drying, which preserves the quality and sensory properties of the product. In addition, the process is energy-efficient and causes no CO2 emissions.

Althen has developed a highly specialised miniature force sensor for these processes, which can withstand the extreme environmental conditions and determine the degree of drying of the product via the product weight.

General mode of operation of the
pure steam drying

First, water is heated in a boiler or other steam generator to produce pure steam. Steam temperatures of 100° and 200°C can be achieved. Pure steam is saturated steam without impurities and is often brought to a specific temperature and pressure to ensure optimum drying conditions.

The pure vapour generated is fed into the drying chamber or dryer. This room contains the product to be dried, which is placed in a special drying basket. The clean vapour condenses on the surfaces of the product to be dried. The condensation releases the latent heat of the vapour and transfers it to the product. This heat causes the moisture in the product to evaporate. The water resulting from the vaporisation is removed from the dryer or recycled.

Possible applications

Pure steam drying is used in various industries, including

• Food industry: drying of fruit, vegetables, spices, coffee and tea.
• Pharmaceutical industry: drying of sensitive active pharmaceutical ingredients.
• Chemical industry: drying of chemical intermediates and fine chemicals.

Other possible areas of application are the textile industry, cardboard and paperboard and products such as ceramics, salt & minerals, soils and sewage sludge.

Advantages of pure steam drying

Pure steam drying is an advanced technology that is used for high-quality and efficient drying processes.

• Gentle drying: As the temperature of the pure steam is controlled and no direct heat is applied to the product, sensitive ingredients such as vitamins, flavours and textures are protected.
• Uniform drying: The process enables the product to be dried evenly, resulting in higher product quality.
• High energy efficiency: The use of pure steam and the ability to recover condensation heat make the process energy efficient.
• Hygienic conditions: As the pure steam is pure and contains no impurities, the product remains hygienic.