Abstract: Control of the seal of a rotary regenerative air preheater is provided by a plurality of inductance sensors (S1-S8) arranged around the path of travel of seal parts borne by the rotating part of the preheater. When these are sealing frames borne on hoods of a stationary matrix type preheater (12) drive means such as magnetic actuators (5) are fed power signals through slip rings (4). When they are seal strips on a rotating matrix type, the drive means are mounted on the sector plates of the stationary body. A control circuit compares the signals received sequentially from the sensors and drives appropriate one or ones of the drive means to bring the sealing means to a predetermined axial relationship, or to hold them there. The sensors may be paired with comparison sensors in the same environment whereby to reduce errors due to changes in temperature etc.

Abstract: An inductance sensor is intended for determining or controlling the gap between a sealing strip and sector plate in a rotary regenerative air preheater of the rotating-matrix type, the strip being on the matrix and being swept past the non-rotating plate. The sensor has a U-shaped core the legs of which lie in a plane generally corresponding to that containing the sealing strip when nearest to the sensor. The legs have unequal coils on them. Energization of the coils allows information to be derived concerning the gap between the strip and plate which may be recorded, displayed, or directly used to adjust that gap to a desired value by movement of the sector plate.

Abstract: Control of the seal of a rotary regenerative air preheater is provided by a plurality of inductance sensors (S1-S8) arranged around the path of travel of seal parts borne by the rotating part of the preheater. When these are sealing frames borne on hoods of a stationary matrix type preheater (12) drive means such as magnetic actuators (5) are fed power signals through slip rings (4). When they are seal strips on a rotating matrix type, the drive means are mounted on the sector plates of the stationary body. A control circuit compares the signals received sequentially from the sensors and drives appropriate one or ones of the drive means to bring the sealing means to a predetermined axial relationship, or to hold them there. The sensors may be paired with comparison sensors in the same environment whereby to reduce errors due to changes in temperature etc.