What is capillary humidity?

Capillary humidity is a term from physics and describes an effect in which water attracts and collects in narrow, confined spaces. This effect is also known as capillary action. In capillary humidity, moisture first dissolves in the smallest cavities and from there spreads throughout the room.

How does capillary moisture develop?

Capillary moisture occurs when water vapor condenses on cold surfaces and adheres to these surfaces in the form of liquid. This is especially the case when the air temperature is lower than the surface temperature and damp material is present. Poorly insulated rooms or lack of ventilation systems also favor the development of capillary moisture.

Where does capillary moisture occur?

Capillary dampness occurs in buildings whose hydro-insulation is non-existent or damaged. The main building materials are porous, the surface tension of the ground water causes it to rise in the tiny capillaries in the wall building material and also spreads to the basement.

The most important signs of developed capillary moisture

Capillary dampness can be recognized by various signs, for example by fine condensation trails on window panes or by increased humidity in rooms. Cracks can be seen on wall paint, mold stains as well as peeling paint also indicate excessive moisture.

• Unpleasant smell of moisture
• Mold growth
• Plaster falling off the wall; stratification of the walls
• Lime and nitrates appearing on the wall surface
• Appearance of salt on the wall surface
• Exceptionally cold surfaces

The water, enriched with the salts contained in the soil, can rise up to 1.5 meters and more above the ground level. Then it begins to dry on the surface of the wall, resulting in the formation of salt deposits and the chemical decay of the plaster of the wall. Frost accelerates this process. A new plaster and the so-called dehumidifying plaster alone can not dry damp walls.

How to eliminate capillary moisture?

There are several ways to eliminate capillary dampness: First, find out where the moisture is coming from and eliminate the cause if possible. Good insulation of the building and opening windows or doors to ventilate the room when the outside temperature is dry can help reduce humidity. A heating system can also help reduce humidity and protect the building against condensation.

However, to effectively remove deeper capillary moisture, a specific drying process must be used. In process engineering, there are various drying methods such as adsorption drying, evaporation drying, or fluidized bed drying. These processes use different methods and equipment – depending on the requirements – to effectively dry a specific product or material. For larger applications, drying systems with high performance and specially adapted process sequences are available.

Relevance to product manufacturing

The problem of capillary moisture can also affect products or manufacturing processes when moisture enters the product and collects on the surface. It often comes from the environment or from the materials used themselves. If the product is not properly dried, this moisture can cause damage and significantly affect product quality.

Especially in bulk processing, the problem is common and can lead to production downtime and loss of quality.

The best way to prevent capillary moisture in bulk solids processing is to optimize the drying process. To do this, the choice of a suitable drying process is first of all crucial.

At Ebbecke Verfahrenstechnik in Bruchköbel, various sophisticated processes and special plants are used in the field of contract drying to reliably eliminate capillary moisture, surface moisture or crystal moisture and to achieve an optimum drying result. We will be pleased to advise you on the possibilities!