SYSTEM AND METHOD FOR NON-CONTACT SENSING TO MINIMIZE LEAKAGE BETWEEN PROCESS STREAMS IN AN AIR PREHEATER

摘要

A rotary air preheater 10 includes a housing 12 having a rotor 14. The rotor 14 has opposing ends 20,24 and is divided into sections by diaphragms 48. Sector plates 28 include one sector plate 28 in sealing relation with one of opposing ends 20,24 of the rotor 14. The air preheater 10 includes a flange 56 and a sensing device 49 coupled to at least one of the sector plates 28. The sensing device 49 provides non-contact sensing of a distance between the sector plate 28 and the flange 56. The sensing device 49 includes a conduit 54 that directs a jet of compressed air onto the flange 56, a first pressure sensor 60 and a second pressure sensor 70. The first pressure sensor 60 senses pressure inside the sensing device 49, and the second pressure sensor 70 senses pressure outside the sensing device 49. The distance between the sector plate and the flange is a pressure difference measured by the first and the second pressure sensors 60, 70. In one embodiment, the first pressure sensor 60 senses a backpressure within the sensing device 49.