Abstract: A rotary regenerative air preheater has a preliminary heating stage for the cold air, before it reaches the regenerative mass, constituted by recuperative heating surfaces provided within the ducting which brings the cold air to the regenerative mass and which are heated by exhaust gas which has passed through the regenerative mass but has lost least heat to that mass. The surfaces take e.g. the form of tubes passing through the channel and gas is guided into these tubes by a gas-catching wing extending to close to one face of the regenerative mass.An embodiment of each of a rotating-and a stationary-mass preheater are described.

Abstract: A regenerative air preheater with cylindrical regenerator chamber and sealing frames at its axial ends with adjustable automatic thermal compensating devices for uniformly maintaining a constant sealing gap by adjustable means under different heat distortions of the regenerator chamber. The sealing frames are movable on spring-loaded pins and the axial travel of said frames is automatically equalized to the axial distortions of the regenerative chamber by said automatic thermal compensating devices in such a way, that they may follow the axial distortion movement of the regenerator chamber in a constant distance of a predetermined sealing gap, which had been adjusted, said compensating devices are controlled by their temperature-responsiveness, preferably in accordance with the mean temperature difference across the mass. As shown, they are made up by partially compensating thermal expansive devices, tied to a lever linkage with adjustable means.

Abstract: Gas treatment such as scrubbing or purificatory heating is carried out by treatment means in permanent gaseous communication with one end face of a rotary regenerative heat exchanger. At the other end face conventional inlet and outlet gas collecting arrangements are provided. A plenum chamber beyond or containing the treatment means allows for flow reversal of the gas treated, so that it may repass through the heat exchanger. Since collecting arrangements are provided at only one end face, the concomitant sealing arrangements need only be provided at that end face, and the rest of a support structure for the heat exchange mass (and which may also support at least some of the further treatment means) may be made of materials chosen solely with a view to resisting the physical and/or chemical conditions likely to be encountered.