The notched base ring comprises a base ring sheet body including a top portion, a bottom portion, a first end connecting the top portion to the bottom portion, and a second end connecting the bottom portion to the top portion. The top portion includes a plurality of attachment lugs and defines a plurality of notches, each notch being at least partially defined by two lugs disposed on opposite sides of the notch, the top portion also including an angled top edge that is disposed at each of the attachment lugs, and the bottom portion includes a bottom support edge.

Transition castings are disclosed which comprise a steam tube, a water tube, and a pass-through tube, which are joined together by membranes. The ends of the tubes on one vertical end are aligned in a plane, while the ends of the tubes on the other vertical end are aligned in alternating planes, or put another way are angled instead of being in a straight line. The transition castings are used in a transition section of a boiler in which the furnace is divided into a lower furnace and an upper furnace. The lower furnace uses water-cooled membrane walls, while the upper furnace uses steam-cooled membrane walls that act as superheating surfaces. The transition section joins the lower furnace and the upper furnace together.

Embodiments of a high temperature fluid generator are adapted to heat a fluid to a high temperature using a heat source. The generator employs a forced circulation counter flow design including a furnace section, a convection section and a pair of L-shaped headers connected to tubes in the furnace and convection sections. In various embodiments, the headers are positioned on diagonally opposite corners and convection tubes are positioned at least partially outside of a flue path for the combustion gas.

The notched base ring comprises a base ring sheet body including a top portion, a bottom portion, a first end connecting the top portion to the bottom portion, and a second end connecting the bottom portion to the top portion. The top portion includes a plurality of attachment lugs and defines a plurality of notches, each notch being at least partially defined by two lugs disposed on opposite sides of the notch, the top portion also including an angled top edge that is disposed at each of the attachment lugs, and the bottom portion includes a bottom support edge.

A liquid heating apparatus includes a top portion with a burner unit, a coil, an external housing, and an internal housing. The burner unit is arranged to burn a fuel so as to generate a downward directed flame. The coil includes first and second layers of windings. The internal housing is arranged within the external housing. The apparatus is in a substantially upright position during operation. A compartment between the internal housing and the external serves as a first liquid reservoir. The flame from the burner unit is peripherally contained by an inner part of the first layer of windings of the coil. The first layer of windings is configured to direct the flame or exhaust gases downwards. The flame or exhaust gases are redirected such that the they contact all of the second layer of windings, the internal housing inner wall, and the first layer of windings

The invention provides a condensing boiler 100 including a heat exchanger 160, the heat exchanger including at least one fluid flow cassette 162a, 162b, 163a, 163b, 164a, 164b, each cassette comprising first 181 and second 182 sheets, wherein at least the first sheet has corrugations 185, 186, 187 along a length of the sheet so as to form a number of grooves extending across a width of the sheet, wherein the second sheet is attached against the first sheet so as to enclose the grooves to form a number of fluid flow passageways 193 extending across a width of the cassette in between the first and second sheets, and wherein the cassette is substantially curved across its width such that the fluid flow passageways are substantially curved along their length. The invention also provides a method of manufacturing a heat exchanger or condensing boiler.

A high temperature fluid generator is configured to heat a fluid (e.g. water; thermal oil or the like) to a high temperature (e.g. greater than 250 degrees Fahrenheit or 120 degrees Celsius) using a fuel-burning furnace. The generator generally comprises a furnace module, wherein fuel is burned, and a convection module where the combustion gases are put in contact with a series of fluid-bearing convection tubes. The furnace module comprises a series of fluidly interconnected headers, some of which are also fluidly connected to the convection tubes in the convection modules. The various headers contribute to the overall structure of the generator. The convection tubes are arranged into at least two bundles which are movably mounted in the convection module of the generator such to be movable in and out of the convection module for inspection, cleaning, maintenance and/or repair.

Transition castings are disclosed which comprise a steam tube, a water tube, and a pass-through tube, which are joined together by membranes. The ends of the tubes on one vertical end are aligned in a plane, while the ends of the tubes on the other vertical end are aligned in alternating planes, or put another way are angled instead of being in a straight line. The transition castings are used in a transition section of a boiler in which the furnace is divided into a lower furnace and an upper furnace. The lower furnace uses water-cooled membrane walls, while the upper furnace uses steam-cooled membrane walls that act as superheating surfaces. The transition section joins the lower furnace and the upper furnace together.

The invention provides a condensing boiler 100 including a heat exchanger 160, the heat exchanger including at least one fluid flow cassette 162a, 162b, 163a, 163b, 164a, 164b, each cassette comprising first 181 and second 182 sheets, wherein at least the first sheet has corrugations 185, 186, 187 along a length of the sheet so as to form a number of grooves extending across a width of the sheet, wherein the second sheet is attached against the first sheet so as to enclose the grooves to form a number of fluid flow passageways 193 extending across a width of the cassette in between the first and second sheets, and wherein the cassette is substantially curved across its width such that the fluid flow passageways are substantially curved along their length. The invention also provides a method of manufacturing a heat exchanger or condensing boiler.

A high temperature fluid generator is configured to heat a fluid (e.g. water; thermal oil or the like) to a high temperature (e.g. greater than 250 degrees Fahrenheit or 120 degrees Celsius) using a fuel-burning furnace. The generator generally comprises a furnace module, wherein fuel is burned, and a convection module where the combustion gases are put in contact with a el series of fluid-bearing convection tubes. The furnace module comprises a series of fluidly interconnected headers, some of which are en.) also fluidly connected to the convection tubes in the convection modules. The various headers contribute to the overall structure of the generator. The convection tubes are arranged into at least two bundles which are movably mounted in the convection module of the generator such to be movable in and out of the convection module for inspection, cleaning, maintenance and/or repair.