Abb Air Preheater Inc.

Alstom (switzerland) Ltd

Abb Preheater, Inc.

Mark E Brophy

Wayne S Counterman

Harlan E Finnemore

Glenn D Mattison

Rex R Snider

Michael Zakel

Robin B Rhodes

Robin Rhodes

William C Cox

Jon R Cowburn

Michael W Wonderling

Steven M Gustin

Thomas G Geyer

A semi-modular rotor module for an air preheater having a circular rotor includes a lug assembly having a lug front, a lug back spaced radially outward from the lug front, and cold end and hot end lug members. The lug front and lug back each extend longitudinally from a first end to a second end, with the cold end lug member being mounted to the first ends of the lug front and the lug back and the hot end lug member being mounted to the second ends of the lug front and the lug back. A single main diaphragm extends radially from an inner end portion to an outer end portion, with the inner end portion being mounted to the lug front on a first side of the lug assembly. The outer end portion is mounted to a rotor shell which is spaced radially outward from the lug back. At least one intermediate diaphragm extends radially from an inner end portion, mounted to the lug back at a position intermediate the first and second sides of the lug assembly, to an outer end portion mounted to the rotor shell.

Semi-modular rotor module

Modular heat exchange baskets for rotary regenerative air preheaters have radially extending tie bars which are positioned at each of the top and bottom side edges of the basket and which tie together the inboard and outboard end frames. These tie bars are located inside of the side edges of the heat exchange plates such that the plates extend out beyond the tie bars. This reduces the bypass gap between baskets.

Regenerative heat exchanger

The rotor for a rotary regenerative air preheater is fabricated from upper and lower rotor shell segments and hot-end and cold-end heat exchange baskets having closed outboard ends, the rotor shell segments and heat exchange baskets defining a first gap between the upper rotor shell segment and the hot-end heat exchange basket, a second gap between the hot-end and cold-end or intermediate heat exchange baskets, and a third gap between the cold-end heat exchange baskets and the lower rotor shell segment. A system for sealing the gaps includes first, second and third sealing members, each sealing member having first and second portions. The first sealing member is mounted to the upper rotor shell segment or the hot-end outboard heat exchange basket and engages the other of the upper rotor shell segment or the hot-end outboard heat exchange basket to seal the first gap. The second sealing member is mounted to the hot-end or the cold-end or intermediate heat exchange baskets and engages the other of the hot-end or cold end heat exchange baskets to seal the second gap. The third sealing member is mounted to the cold-end heat exchange basket and engages the other of the lower rotor shell segment to seal the third gap.

Air preheater adjustable basket sealing system

The heat exchange baskets for a rotary regenerative air preheater are loaded radially into the rotor rather than axially from the duct end. The rotor is divided into sectors by diaphragms, and support gratings are provided in each rotor sector with the baskets being positioned and supported on the gratings. The baskets are removed from the rotor with a removal lug or tool which includes a lever portion and a hook portion with a beveled edge. The beveled edge and then the entire hook portion are inserted under the outer edge of a basket and then rotated with the lever portion whereby the hook portion engages the basket. The lug or tool is then pulled outwardly to remove the basket.

Rotary regenerative heat exchanger

A rotary regenerative air preheater has pinrack seals including a U-seal located between the upper and lower pinrack rails and a trough-shaped filler-seal located between the upper and lower pinrack supports of adjacent pinrack assemblies. The inboard edges of the wing portions of the filler seal are welded to the rotor shell, the outboard edge of each leg portion of the U-seal engages a pin in one of the adjacent pinrack assemblies, and the upper and lower edges of the U-seal and the filler-seal engage the upper and lower pinrack rails and the upper and lower pinrack supports, respectively, to seal the pinrack assemblies to the rotor shell.

Semi-modular pinrack seal

A rotary regenerative air preheater has heat exchange baskets which contain the mass of heat absorbent material commonly comprised of stacked plate-like elements. The heat exchange basket comprises a frame which is open on each end and which is closed on the sides by basket cover assemblies. Each basket cover assembly includes a light gauge membrane which is welded to the interior surface of the basket cover. Shrinkage of the membrane due to the weld imposes a pre-tension on the membrane which resists deformation of the cover assembly by the heat exchange elements.

Pre-stressed membrane basket cover assembly

An arrangement is provided in an air preheater for mounting and adjusting the axial seal plates in relation to the rotor using a reduced number of adjustable mountings and replacing the remaining adjustable mountings with adjustable compression stops. These adjustable compression stops engage but require no attachment to the axial seal plates. This reduces the work necessary in the limited space between the air preheater housing and the axial seal plates thereby reducing costs and facilitating installation and replacement.

Adjustable axial seal plates for rotary regenerative air preheaters

The rotor for a rotary regenerative air preheater is fabricated from a combination of shop assembled rotor sector modules and field assembled components so as to eliminate the double plate diaphragms of conventional modular rotors. The shop assembled modules comprise one or more sectors and the field assembled components fit between the spaced shop assembled modules spaced around the rotor hub. The support gratings between the diaphragm plates support modular heat exchange baskets which are loaded into the rotor radially from the periphery.

Air preheater with semi-modular rotor construction

The heat exchange baskets for a rotary regenerative air preheater are loaded radially into the rotor rather than axially from the duct end. The rotor is divided into sectors by diaphragms, and support gratings are provided in each rotor sector with the baskets being positioned and supported on the gratings. The angle of each rotor sector is smaller than the complimentary angle of each basket such that the outboard end of each basket can contact the diaphragms before the contact of the inboard end. The baskets thereby serve to stiffen the rotor structure while reducing bypass gaps.

A rotary regenerative air preheater has a rotor which is divided into sectors by diaphragm plates. Mounted between these diaphragms are support gratings which support the heat exchange baskets with there being at least two circumferentially adjacent full-wrapper baskets on each support grating. The gratings include radial seals which extend axially into the spaces between these adjacent baskets to provide a seal to minimize circumferential fluid flow. Attached to the radial seals at the axial ends of the rotor are seal strips which form a seal with the sector plates on the rotor housing thereby forming a double seal to minimize cross flow between the gas side and the air side.

A heat transfer element basket assembly for a rotary regenerative heat exchanger having a splitter plate or stiffening member mounted between the heat transfer plates at a position intermediate between the inner and outer ends of the basket. The stiffening member includes elongated slots adjacent the top surface which accommodate lifting lugs. Elongated slots and lifting lugs also may be included adjacent the bottom surface of the basket. These lugs slide up and down within the elongated slots to an extended position partially above the surface of the basket when in the lifting mode and to a retracted position fully below the surface when not in use. Since the lugs are retracted when the basket has been placed in the rotor, they will not interfere with the vertically adjacent baskets. This means that the baskets have a low profile and can be tightly packed in the rotor.

Means for lifting heat transfer element baskets

Ceramic blocks which may be catalyst coated having gas flow channels therethrough are supported in a metal framework to form a removable basket for a rotary regenerative air heater. The blocks are supported between compressed packing material with individual rows being supported at one inlet edge and the opposite outlet edge by Z-plates.

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Wellsville, NY, United States of America

Mark E Brophy