Dampfgrad

Dampfgrad is a term used in German-speaking boiler and steam engineering to describe the degree to which steam is dry or superheated. It is not an international standard quantity with its own unit, but a descriptive notion tied to steam quality and the temperature of the steam relative to its saturation state at a given pressure.

In practice, Dampfgrad often corresponds to the concept of steam quality or dryness fraction. A dryness fraction of one indicates dry saturated steam, while a value below one denotes a mixture of vapor and liquid water (wet steam). When the steam temperature exceeds the saturation temperature for the given pressure, the steam is superheated, and its Dampfgrad is understood to be higher than that of saturated steam.

Measurement and interpretation of Dampfgrad rely on pressure and temperature data, often using steam tables, thermodynamic relations, or indirect methods such as throttling calorimetry and moisture monitoring in boilers. In many technical texts, Dampfgrad is used loosely to describe the degree of superheat or the overall quality of the steam supply, without assigning a fixed unit.

Applications of Dampfgrad are central to steam systems in power generation, process heating, and propulsion. A higher degree of superheat (higher Dampfgrad) can improve turbine efficiency and reduce moisture-related erosion, while wet steam (lower Dampfgrad) can decrease heat transfer efficiency and increase corrosion or deposition risks.

See also: saturated steam (sättigungsdampf), superheated steam (überhitzter dampf), steam quality (dampfqualität), dryness fraction (feuchtegehalt).