Loading patent…
AssigneeDavidson & Company Limited
InventorsJohannes Cornelis Blom, Colin Edward Tindall
Estimating the term…
A rotary regenerative air preheater has electromagnetic drive devices to adjust the relationship between an end face of the regenerative mass and a sealing frame on a duct part. Electrical control means are responsive to signals generated by contact between the sealing shoe (or special sensors) borne on the frame and the end face, to drive the electromagnetic devices and break the contact. The control may be on/off, a time response such that a desired maximum clearance is experienced, or may be responsive to drag (i.e., the angle of arc over which contact is experienced). The electromagnetic drive devices are inherently self adjusted by having an air gap in their flux circuit which varies in dependence on the position of the sealing frame.
A rotary regenerative preheater comprising a regenerative mass having two axial end faces and a central axis, ducts for conducting heat-exchange media to and from the regenerative mass, at least one said duct comprising a sealing frame in close axial relationship with one of the end faces of the regenerative mass, means for causing relative rotation of the mass and the at least one sealing frame about the central axis, electrical contact means associated with the end face and with the sealing frame for changing the condition of an electrical circuit upon deviation from a desired said axial relationship of the end face and frame, electromagnetic drive means operatively linked to the sealing frame for altering the axial relationship with the said one end face, and control means responsive to the condition of the said electrical circuit to operate automatically to cause drive of the electromagnetic drive means and effect control of the said axial relationship.
In a rotary regenerative preheater with a duct for conducting heat exchange medium to and from a heat-exchange mass, means for causing relative rotation of the duct and the mass about a central axis and an adjustably axially movable sealing means for sealing between the duct and an axial end face of the mass the improvement comprising contact means effective to open and close an electric circuit in dependence on the axial relationship of the sealing means and the said axial end face, electromagnetic drive means for causing axial movement of the sealing means and control means responsive to at least one of the opening and closing of the electric circuit arranged and adapted to respond to said circuit for controlling operation of the electromagnetic drive means to adjust the relationship in the axial direction between the sealing means and the axial end face of the mass.
Dependencies are inferred from the claim text.