Primary Air Circuit Leakages

You can get non-metallic high or low temperature flexible joints that bolt on each side of a joint. This should eliminate leakage at this point. As for gates - you may have the wrong seal design. I used to desiggn gates up to about 20ft x 20 ft. Using spring-loaded seals (frame mounted) buckling was ever a problem. there might be some minimal leeakage at the seal joints, approx every 6 ft. If you pot seal air in the seal area a 100% seal would result. These units were used im USA, UK, Germany, Far East. Canada and more recently China and no problems were reported.

Sir, As for expansion bellows, We are trying to supplement the present metallic bellows with Fabric bellows. But since It may not be possible for all the bellows on the boilers, Can you suggest some efficient Abrasion resistant and corrosion resistant coatings for apllication inside and outside the bellows respectively.? As for gate seals, We are searching for better seal materials. Are you sure that spring loaded seals are not so efficient? Also, can you suggest a better material than SS, which will be more flexible, so as not deform permanently?

Thirdly, There is heavy leakage from between Labrynth seal cover and fan casing, which is presently only clamped with cloth mesh. The cloth mesh is not able sustain for long. I would like to know from some industrial fan manufacturers, what is ussually applied in that region? Our BHEL P.A Fan has a labrynth seal enclosed in a seal cover. But there exists about 1--1.5 inch gap between the casing and the seal cover.

Sir, Regarding your reference on seal air for the gates, it is not feasible as we are facing the problem of reduced coal O/L temp due to mixing of hot primary air with this gate seal air. So gate sealair facility is kept out of service.