Abstract: A screen (10) for separating particles according to size, being made up of a plurality of first straight wires (14) extending in one direction, and a plurality of alternating crimped second wires (12) extending in the same direction. A plurality of third straight wires (16) extend in the other direction, and are interwoven with each of the first and second wires. The first wires are 11/2 to 21/2 times the diameter of the second and third wires, which are of the same diameter.

Abstract: A pair of parallel flow rotary regenerative air heaters (16, 18) which extract heat from the combustion gases exhausted from a furnace (10). The gases, after giving up heat in the air heaters, flow to an electrostatic precipitator (30). In order to eliminate any temperature unbalance across the width of the main duct (28) leading to the precipitator, the duct (24) from the first air heater is connected to the main duct in such a manner that the hottest portion of the gases (H-1) are introduced along one side, and the relatively cooler portion (C-1) of the gases are introduced along the other side. The duct (26) from the second air heater is connected to the main duct in such a manner that the relatively cooler portion of the gases (C-2) are introduced along said one side, and the hottest portion of the gases (H-2) are introduced along said other side, thereby eliminating temperature unbalances across the width of the main duct.

Abstract: An economizer (16) located in the rear pass (12) of a steam generator having a vertical tube panel containing a plurality of parallel, vertically spaced horizontal tube portions (22) and a support therefor including a pair of plates (32, 34), one positioned on either side of the tube panel. First tabs or bars (46) which are integral at one end (50) with the first plate (32) extend horizontally beneath and support every other, or alternate horizontal tube portions (22), and are welded (52) to the second plate (34) at their other ends. Second tabs or bars (44) which are integral at one end (48) with the second plate (34) extend horizontally beneath and support the remaining, alternate horizontal tube portions (22) not supported by the first bars (46), and are supported at their other ends by ledges (54) contained on the first plate (32).

Abstract: A maintenance platform for reaching the upper area of the furnace (10) of a steam generator that can be quickly and easily assembled during a maintenance shutdown. The grid or frame of the platform is made up of a plurality of beams (22) extending into the furnace from opposite furnace walls (19). Cables (50) from the roof (60) support one end of the beams. Planking (66, 68) that interlocks (62, 64, 70) with the beams (22) completes the platform.

Abstract: A maintenance platform is provided for gaining access to the upper area of the furnace (10) of a steam generator that can be quickly and easily assembled during a maintenance shutdown. The main beams (26) forming the framework of the platform are supported both from the furnace walls (42, 44) and also from the furnace roof (32, 34, 38). These beams, which are of considerable length, are stored outside of the furnace in a nearly vertical position when not in use, and are guided into the furnace by a plurality of rollers (40), so as to keep the beams in a single plane close to the outer furnace wall while they are being moved into the furnace.

Abstract: An apparatus for inserting cleaning plugs into the ends of tubes to be cleaned including a tool, a handle on the tool capable of being held by an operator, a chamber having an open end capable of being aligned with the open end of the tube to be cleaned, a first ram opposite the open end, a first piston-cylinder capable of moving the ram through the chamber and retracting it therefrom thereby forcing a cleaning plug into the tube, a magazine opening laterally from the first ram and open end into the chamber, a second ram positioned so as to move cleaning plugs from the magazine into the chamber, a second piston-cylinder capable of moving the second ram through and retracting it from the magazine, a housing for a chain of cleaning plugs, the housing opening into the magazine, a gas source maintaining a constant pressure on the chain of cleaning plugs so as to force a cleaning plug into the chamber when nothing else occupies it, and a trigger on the handle which in a first position pressurizes the second piston

Abstract: A nuclear steam generator including a vessel, means to introduce vaporizable fluid into the bottom portion of the vessel, an outlet near the top through which vapor is discharged, a horizontal tube sheet extending across the vessel, a plurality of U-shaped tubes, having each end secured to and extending through the tube sheet, means for introducing heating fluid to one end of each of the U-shaped tubes, means for removing heating fluid from the other end of each of the U-shaped tubes, tube support means positioned within the vessel for preventing tube vibration, the tube support means including horizontally positioned means closely surrounding, but slightly spaced from each tube, means through which access can be had to the vessel interior beneath the tube sheet when the steam generator is not in operation, and testing means for determining whether or not a tube is locked into a tube support means including a longitudinal member, with a first end located inside the tube to be tested, and a second end located

Abstract: A fluidized bed furnace (10) is provided having a perforate grate (9) within a housing which supports a bed of particulate material including some combustibles. The grate is divided into a plurality of segments (E2-E6, SH1-SH5, RH1-RH5), with the airflow to each segment being independently controlled. Some of the segments have evaporating surface imbedded in the particulate material above them, while other segments are below superheater surface or reheater surface. Some of the segments (E1, E7) have no surface above them, and there are ignitor combustors (32, 34) directed to fire into the segments, for fast startup of the furnace without causing damage to any heating surface.

Abstract: A timer system (10,110,210) of two or more timers (10,110,210) measures the response time between an initiating event and a dependent event. The initiating and dependent events may be physically separated or electrically isolated. The timer system (10,110,210) permits recording of associated initiating and dependent events for a response time test followed by the recording of additional associated initiating and dependent events for additional response time tests while the timers remain separated. Thus, the timer system (10,110,210) permits serial recording of information for a large number of response time tests. The timers (10,110,210) may be identical. The timers (10,110,210) are interconnected and synchronized, then disconnected and separated to record the time of occurrence of the physically separated or electrically isolated events. The timers (10,110,210) are then again interconnected for a simultaneous recording of the elapsed time on each timer.

Abstract: A fluidized bed furnace is provided in which liquid fuel can be burned. Injectors extend up through an imperforate bed plate which properly mix the oil or other liquid fuel with the fluidizing air causing evaporation of the oil. This mixture is passed through restricted openings as it enters the fluidized bed, thus resulting in high velocity flow and fairly even fuel and combustion distribution throughout the cross-section of the fluidized bed.

Abstract: A furnace (10) in which coal and cellulose fuel can both be burned on the same traveling grate (24). First means (36) are provided for introducing coal onto the grate at one end (38), such that it traverses the full grate run before it falls as ash from the other end (56) of the grate. Second means (48, 52) are provided for introducing cellulose fuel onto the grate at a central or middle location (54). Adjustable means (49, 50) are provided for varying the point at which the cellulose fuel is introduced onto the grate. If cellulose fuel having a relatively slow burning rate is being combusted, the adjustable means are set so as to introduce the fuel at a point on the grate further away from the discharge end. If cellulose fuel having a relatively fast burning rate is being combusted, the adjustable means are set so as to introduce the fuel at a point on the grate closer to the discharge end.

Abstract: In combination, a top-supported furnace (10) in which an ash-bearing fuel is burned, opening means (12) in the furnace bottom, a bottom supported tank (16) open at its upper end and containing water (18) positioned beneath the furnace opening means (12), into which the ash from the furnace (10) falls, means (20) for removing the ash from the tank (16), an intermediate transition piece (26) hydraulic drive means (30) carried by the tank (16) for moving the transition piece (26) between a first position spaced from the furnace bottom, and a second position in engagement with the furnace bottom, means (32, 34) for removably securing the transition piece (26) to the furnace bottom, seal means (36) which completely surround the furnace bottom for sealing the space between the transition piece (26) and the furnace bottom when the transition piece (26) is in its second position, stop means (38) for limiting the movement of the transition piece (26) towards the furnace bottom to prevent the seal means (36) from becom

Abstract: The method of operating a furnace including the steps of conveying (30) pulverized coal in an air stream towards a furnace (10), separating (34) the stream into two portions (36,38), one being a fuel rich portion (38), and the other being a fuel lean portion (36), introducing (40) the fuel rich portion into the furnace in a first zone, introducing (42,44) air into the first zone in a quantity insufficient to support complete combustion of all of the fuel in the fuel rich portion, introducing (46) the fuel lean portion into the furnace in a second zone, introducing (48) air into the second zone in a quantity such that there is excess air over that required for combustion of all of the fuel within the furnace, and introducing (50) lime into the furnace simultaneously with the fuel, so as to minimize the peak temperature within the furnace, and also minimize the formation of NO.sub.x and SO.sub.x in the combustion gases.

Abstract: In combintion, a vertical gas pass (12) through which hot gases flow, a heat exchanger including a first tube panel (24, 26) having serpentine tube means, each tube means having a plurality of first (24, 26) horizontal tube portions, said heat exchanger having a second tube panel (32, 34) having serpentine tube means, each tube means having a plurality of second (32, 34) horizontal tube portions which lie adjacent to and in the same horizontal planes as the first (24, 26) horizontal tube portions, the upper terminal ends of the serpentine tube means having first vertical runs (24, 26) extending downwardly to a point beneath the bottom of the serpentine tube means, and having U-bends (28, 30) at the bottom, and having second vertical runs, which bend at the top and are integral with the uppermost horizontal tube portions, lug means (40) attached to opposite sides of some of the vertical runs (24, 26), a plurality of band means (42) encircling adjacent first and second horizontal tube portions (24, 32) the ends

Abstract: A method and apparatus for removing and replacing the primary manway cover (18) which is secured to the shell (10) of a nuclear steam generator by a multiplicity of nuts (24) and studs (22), including the steps of removing two of the studs and replacing them with two overlength special studs (30); removing the nuts (24) from all of the other studs (22); unthreading the nuts (24) on the overlength studs (30) until the cover (18) is positioned outside the ends (28) of the other studs (22); attaching (44) a cable (40) to the periphery of the cover; removing one of the overlength studs (30); and pivoting the cover (18) on the other of the overlength studs (30) out of alignment with the manway opening while supporting it by means of the cable (40).

Abstract: Apparatus for supporting screen (12) in a screening machine (10) that will permit long-life of the screen even when subjected to heat and vibration. The screen or wire cloth edge is folded over (30) and fastened or joined (42, 44, 46), with a metal rod (32) inserted down through the foldover space (34). Spring clips (40) or other adjustable tensioning devices attach the steel rod (32) to the screening machine frame (50), thus placing the screen (12) in tension.

Abstract: Apparatus for handling ash and slag produced in the combustion of coal or other ash-bearing fuel in the furnace (10) (not shown) of a steam generator, including a submerged scraper conveyor (20) beneath the furnace, and a water seal including plate means (24) extending from the furnace bottom or transition chute into the water (18) in the tank (16) housing the scraper conveyor, which plate means (24) also form a seal at their upper ends (40,42) with the furnace bottom or transition chute, for preventing the atmosphere from being exposed to the furnace interior. A motor (50,52) is provided for moving the plate means (24) upwardly and downwardly, to allow the submerged scraper conveyor (20) and its tank (16) to be quickly removed from beneath the furnace (10) when the unit is shut down for maintenance purposes.

Abstract: A fluidized bed furnace (10) for generating steam (26) is designed to operate over a given load range, for example from 50% of full load to maximum capacity rating (MCR). The air distributor (12) is designed with a constant pressure drop restriction means or "float" (36) in each air inlet (18). As the load varies, the pressure drop across the float (36) will remain constant, reducing the overall fan horse power requirements.

Abstract: Apparatus for handling ash and slag produced in the combustion of coal or other ash-bearing fuel in a top-supported furnace (10) of a steam generator, including a submerged scraper conveyor unit (14) beneath the furnace (10), and a water seal (24, 26) including a bottom-supported trough (26) positioned beneath the furnace (10), and plates (24) secured to the furnace bottom extending down into the trough (26). The submerged scraper conveyor unit (14) is bottom-supported independently of the trough (26), and there is an adjustable (34) seal member (29) between the two to prevent gas leakage therebetween.

Abstract: A loose fitting movable cover plate (36), suitable for the severe service encountered in a fluidized bed combustor (10), restricts the flow of solids into the combustor drain lines (30) during shutdown of the bed. This cover makes it possible to empty spent solids from the bed drain lines which would otherwise plug the piping between the drain and the downstream metering device. This enables use of multiple drain lines each with a separate metering device for the control of solids flow rate.