In practice, rotary drums are usually designed for operation under vacuum conditions. In this paper, a novel technique is proposed for sealing the rotary drums under pressurized operating conditions. The proposed system is based on applying a secondary pressurized volume around the leaking gap of the drum. By maintaining the pressure of this volume a little above the pressure of the drum, it is possible to prevent leakage of gases to the ambient environment. The objective of the controller in this system is to keep the pressure of the secondary volume above the pressure level of the drum, independent of the disturbances, which may exerted on the system by the wind outside the drum. The control system is also required to trace the variations in the drum pressure, with the least fluctuations in the pressure difference between the drum and the volume.