Pirani

Pirani is an Italian surname. It is most commonly associated with Marcello Pirani, an Italian physicist whose name is linked to developments in vacuum science and technology. The term Pirani also refers to the Pirani gauge, a type of vacuum gauge named in his honor.

The Pirani gauge measures pressure by exploiting the dependence of a gas’s thermal conductivity on pressure. In a typical device, a thin wire or filament is electrically heated while its temperature is monitored through its electrical resistance. When the surrounding gas is at a given pressure, gas molecules collide with and remove heat from the filament, altering its temperature and resistance. The filament is usually arranged in a measurement circuit, such as a Wheatstone bridge, and the resulting signal is calibrated to indicate pressure. This approach makes the Pirani gauge well suited for monitoring low to moderate vacuum levels and it is commonly used in laboratory and industrial vacuum systems. In practice, Pirani gauges are often paired with other gauges to cover a wider pressure range.

Beyond the gauge, the Pirani name appears in scientific literature related to vacuum physics and thermal conductivity, reflecting Marcello Pirani’s contributions to the field. The surname itself is of Italian origin and may refer to other individuals in various contexts.