Abstract: Disclosed is a heat transfer assembly for a rotary regenerative preheater. The heat transfer assembly includes a plurality of heat transfer elements stacked in spaced relationship to each other in a manner such that each notch from a plurality of notches of one of the heat transfer element rests on respective flat sections from a plurality of flat sections of the adjacent heat transfer elements to configure a plurality of closed channels, each isolated from the other, wherein each of the channels has a configuration in a manner such that each of corrugation sections from a plurality of corrugation sections of one of the heat transfer elements faces respective undulation sections from a plurality of undulation sections of the adjacent heat transfer elements.

Abstract: A stack of heat transfer sheets includes one or more first sheet which includes a first undulating surface formed by first lobes that are parallel to each other and oriented at a first angle. The first sheets include a second undulating surface formed by second lobes that are parallel to each other and oriented at a second angle, different from the first angle. The first sheets include a third undulating surface formed by third lobes extending from one or more ends of the first sheet and terminating at an intermediate point between the end and an opposing end thereof. The third lobes are parallel to each other and parallel to the direction of flow through the stack. The stack includes one or more second sheets defining a plurality of sheet spacing features which engage a portion of the first sheet.

Abstract: Disclosed is a heat transfer assembly for a rotary regenerative preheater. The heat transfer assembly includes a plurality of heat transfer elements stacked in spaced relationship to each other in a manner such that each notch from a plurality of notches of one of the heat transfer element rests on respective flat sections from a plurality of flat sections of the adjacent heat transfer elements to configure a plurality of closed channels, each isolated from the other, wherein each of the channels has a configuration in a manner such that each of corrugation sections from a plurality of corrugation sections of one of the heat transfer elements faces respective undulation sections from a plurality of undulation sections of the adjacent heat transfer elements.

Abstract: A stack of heat transfer sheets includes one or more first sheet which includes a first undulating surface formed by first lobes that are parallel to each other and oriented at a first angle. The first sheets include a second undulating surface formed by second lobes that are parallel to each other and oriented at a second angle, different from the first angle. The first sheets include a third undulating surface formed by third lobes extending from one or more ends of the first sheet and terminating at an intermediate point between the end and an opposing end thereof. The third lobes are parallel to each other and parallel to the direction of flow through the stack. The stack includes one or more second sheets defining a plurality of sheet spacing features which engage a portion of the first sheet.

Abstract: A stack of heat transfer sheets includes one or more first sheet which includes a first undulating surface formed by first lobes that are parallel to each other and oriented at a first angle. The first sheets include a second undulating surface formed by second lobes that are parallel to each other and oriented at a second angle, different from the first angle. The first sheets include a third undulating surface formed by third lobes extending from one or more ends of the first sheet and terminating at an intermediate point between the end and an opposing end thereof. The third lobes are parallel to each other and parallel to the direction of flow through the stack. The stack includes one or more second sheets defining a plurality of sheet spacing features which engage a portion of the first sheet.

Abstract: A heat transfer sheet for a rotary regenerative heat exchanger includes a plurality of rows of heat transfer surfaces each being aligned with a longitudinal axis extending between first and second ends thereof. The heat transfer surfaces have a height relative to a central plane of the heat transfer sheet. The heat transfer sheet includes one or more notch configurations for spacing the heat transfer sheets apart from one another. Each of the notch configurations are positioned between adjacent rows of heat transfer surfaces. The notch configurations include one or more lobes connected to one another, positioned in a common flow channel and extending away from the central plane and one or more lobes extending away from the central plane in an opposite direction and being coaxial. The lobes have height a relative to the central plane that is greater than the height of the heat transfer surfaces.

Abstract: A heat transfer sheet for a rotary regenerative heat exchanger includes a plurality of rows of heat transfer surfaces each being aligned with a longitudinal axis extending between first and second ends thereof. The heat transfer surfaces have a height relative to a central plane of the heat transfer sheet. The heat transfer sheet includes one or more notch configurations for spacing the heat transfer sheets apart from one another. Each of the notch configurations are positioned between adjacent rows of heat transfer surfaces. The notch configurations include one or more lobes connected to one another, positioned in a common flow channel and extending away from the central plane and one or more lobes extending away from the central plane in an opposite direction and being coaxial. The lobes have height a relative to the central plane that is greater than the height of the heat transfer surfaces.

Abstract: A heat transfer sheet [60,160,260,360] for a rotary regenerative heat exchanger is shaped to include sheet spacing features [59], which provide spacing between adjacent heat transfer sheets [60,160,260,360], and undulation surfaces [68,70] (corrugations) in the sections between the sheet spacing features [59]. The undulation sections [68,70] are constructed of regularly spaced lobes [64,72] extending at an angle with respect to the spacing features [59]. The undulating sections [68,70] impart turbulence in the air or flue gas flowing between the heat transfer sheets [60, 160, 260, 360] to improve heat transfer. The heat transfer sheets [60,160,260,360] may include undulating surfaces that differ in angle of their lobes [64,72].

Abstract: A stack of heat transfer sheets includes one or more first sheet which includes a first undulating surface formed by first lobes that are parallel to each other and oriented at a first angle. The first sheets include a second undulating surface formed by second lobes that are parallel to each other and oriented at a second angle, different from the first angle. The first sheets include a third undulating surface formed by third lobes extending from one or more ends of the first sheet and terminating at an intermediate point between the end and an opposing end thereof. The third lobes are parallel to each other and parallel to the direction of flow through the stack. The stack includes one or more second sheets defining a plurality of sheet spacing features which engage a portion of the first sheet.

Abstract: An air preheater 100 is described having an air damper assembly 162 that partially restricts an air inlet 130 and a flue gas damper assembly 152 that partially restricts flue gas inlet 124 during periods of reduced boiler load. Restricting the flue gas inlet 124 reduces the effective surface area of the preheater causing more heat to pass to the cold end of the air preheater 100, reducing acid condensation and fouling. Restricting the gas inlet 124, increases gas velocity, thereby eroding accumulations in the air preheater 100, also reducing fouling. Restricting the air inlet 130 reduces the effective heat transfer surface area of the air preheater, which raises the gas temperature in the cold end of the air preheater and thereby reduces acid condensation and fouling.

Abstract: A heat transfer sheet [60,160,260,360] for a rotary regenerative heat exchanger is shaped to include sheet spacing features [59], which provide spacing between adjacent heat transfer sheets [60,160,260,360], and undulation surfaces [68,70] (corrugations) in the sections between the sheet spacing features [59]. The undulation sections [68,70] are constructed of regularly spaced lobes [64,72] extending at an angle with respect to the spacing features [59]. The undulating sections [68,70] impart turbulence in the air or flue gas flowing between the heat transfer sheets [60, 160, 260, 360] to improve heat transfer. The heat transfer sheets [60,160,260,360] may include undulating surfaces that differ in angle of their lobes [64,72].

Abstract: A fouling sensing system monitors fouling of a rotary regenerative preheater having a housing and a rotor rotatably mounted therein. An emitter for emitting energy is positioned at one of the faces of the rotor and emits energy through the rotor. A sensor is positioned at the other face of the rotor for receiving the energy and generating an output signal indicative of the intensity of the energy.

Abstract: A rotary regenerative air preheater has bypass seals located at the top and bottom of one side of each sector of heat exchange baskets located at the top and bottom of the adjacent diaphragm and sealing the gap between that one side of the baskets and the diaphragm. The bypass seals are metal strips extending along the radial length of the diaphragm with a main body portion attached to the diaphragm and a bent leg portion extending outwardly to engage the baskets. The bypass seals are notched to fit over the stay plates and are attached over the radial seals to hold the radial seals in position.

Abstract: A system and method for detecting hot spots in a rotary regenerative air preheater which compensates for normal variations in the temperature of the incoming hot gas stream or incoming cold air stream. Alarm conditions are based on calculations relating to the average and maximum outlet gas or outlet air over a period of time compared to the air and gas inlet temperature. The alarm is triggered if the maximum values deviate from the time averaged values more than a selected percentage.