摘要 |
A flue-gas to air heat exchanger having a flue-gas containing shell with a heat exchange surface, flue-gas inlet and outlet sections, and at least one tubular clean-out fitting is provided with a removable plug having an outer peripheral portion resiliently engageable with a section of the inner peripheral portion of the fitting adjacent the shell. The plug periphery is expanded into gas-tight sealing contact with the fitting inner periphery by means affording installation and removal without tools.
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