Return to Economizer Information Main Page
The problem with most internal damper arrangments is that they do not provide a physical seperation between the gas bypass channel and the internal tube bundle. If the flue gas is not physically separated from the coil, some gas will inevitably pass over the tubes. This could actually lead to accelerated corrosion as the bulk of the hot flue gas will bypass the coil leaving relatively low temperature tubes unprotected. In a low fire or cycling operation, flue gas could begin to condense on the tube wall which would lead to a premature failure of the economizer, please also see Coiled Economizers .
If your application does require the addition of a damper, the correct type to be specified is an internal bypass arrangment, however the bypass flue gas duct MUST be completely isolated from the tube bundle. This provides for complete isolation of the tube bundle from the flue gas stream. A standard arrangment on most rectangular configuration economizers, these units utilize an opposed blade, louver type damper for flue gas control. Louver type dampers work well for both tube bundle isolation and flue gas bypassing, as well as for heat recovery control via a modulating motor and controller assembly.
Return to Economizer Information Main Page
