Semi-modular rotor module

A semi-modular rotor module for an air preheater having a circular rotor, the rotor module comprising:

• a lug assembly including a lug front and a lug back spaced radially outward from the lug front, the lug front and lug back each extending longitudinally from a first end to a second end, the lug assembly also including a cold end lug member mounted to the first ends of the lug front and the lug back and a hot end lug member mounted to the second ends of the lug front and the lug back, the lug front, lug back, cold end lug member and hot end lug member defining circumferentially spaced first and second sides of the lug assembly;
• a rotor shell spaced radially outward from the lug back;
• a single main diaphragm extending radially from an inner end portion to an outer end portion, the inner end portion being mounted to the lug front on the first side of the lug assembly, the outer end portion being mounted to the rotor shell;
• and
• a plurality of intermediate diaphragms, each intermediate diaphragm extending radially from an inner end portion to an outer end portion, the inner end portions being mounted in circumferentially spaced relationship to the lug back, the inner end portion of the intermediate diaphragm circumferentially spaced furthest from the main diaphragm being mounted to lug back at a position intermediate the first and second sides of the lug assembly, the outer end portion being mounted to the rotor shell.

A circular rotor for an air preheater comprising:

• a plurality of substantially identical, adjacently positioned, shop built rotor modules, each rotor module including
• a lug assembly including a lug front and a lug back spaced radially outward from the lug front, the lug front and lug back each extending longitudinally from a first end to a second end, the lug assembly also including a cold end lug member mounted to the first ends of the lug front and the lug back and a hot end lug member mounted to the second ends of the lug front and the lug back, the lug front, lug back, cold end lug member and hot end lug member defining circumferentially spaced first and second sides of the lug assembly,
• a shop installed rotor shell spaced radially outward from the lug back,
• a single main diaphragm extending radially from an inner end portion to an outer end portion, the inner end portion being mounted to the lug front on the first side of the lug assembly, the outer end portion being mounted to the shop installed rotor shell,
• a plurality of intermediate diaphragms, each intermediate diaphragm extending radially from an inner end portion to an outer end portion, the outer end portion being mounted to the shop installed rotor shell, the inner end portions being mounted in circumferentially spaced relationship to the lug back, the inner end portion of an exposed intermediate diaphragm circumferentially spaced furthest from the main diaphragm being mounted to lug back at a position intermediate the first and second sides of the lug assembly, and
• a plurality of radially spaced, shop installed stay plate assemblies, at least one shop installed stay plate assembly extending circumferentially between the main diaphragm and an adjacent intermediate diaphragm and at least one shop installed stay plate assembly extending circumferentially between the each intermediate diaphragm and an adjacent intermediate diaphragm;
• a plurality of field installed rotor shells;
• and
• a plurality of field installed stay plate assemblies;
• wherein a field installed rotor shell and at least one field installed stay plate assembly extends circumferentially between the main diaphragm of each rotor module and the exposed intermediate diaphragm of each adjacent rotor module.