Abstract: A discharge valve plate of the type used in the conduit between an exhauster fan and a riffle box in a coal fine delivery system for a coal-fired combustion chamber in a power plant. The axis of rotation of the discharge valve plate is oriented generally perpendicular to the axis of rotation of the exhauster fan, such that the valve plate bisects the flow of coal fines from the exhauster fan into upper and lower flows, each having heavy and light distributions across the width of the conduit. The discharge valve plate is provided with diffuser elements engaging the upper and lower flows to cause the heavy and light flow distributions to mix prior to reaching the riffle box.

Abstract: A deflectable vane member for a coal mill pulverizer throat. The vane is yieldingly mounted in the throat with a spring support member whose force is designed to hold the vane rigidly in place during normal operations, and to yield when the vane is struck by large debris with sufficient force. The spring support member causes the vane to spring back into its operative position after it has yielded to the debris.

Abstract: A burner isolation valve or gate for use in the coal-delivery pipes of coal-fired power plants. Safety regulations often require that two valves be placed in the coal delivery line between a combustion chamber and an exhauster or pulverizer type deliver source to isolate the section of pipe in between for maintenance and other access. The invention includes a novel valve plate and actuation assembly, a novel housing adapted to sealingly enclose the valve plate, and a novel sealing mechanism for the valve plate and housing adapted to keep coal fines and dust out of the outboard portion of the housing in which the valve plate rests in the valve-open position.

Abstract: An apparatus for preventing uneven distributions of coal fines in the upper, outlet end of a coal mill classifier. A plurality of static diffuser elements is positioned in the upper end of the classifier, preferably within the classifier skirt if the classifier includes such structure, adjacent the inlets of multiple coal discharge pipes leading from the upper end of the classifier to a combustion chamber. In a preferred form the diffuser elements comprise vertically-arranged toothed bars mounted on the inside wall surfaces of the skirt.

Abstract: In a delivery pipe for pulverized coal fines from a coal mill to a combustion chamber, a device for diffusing unevenly distributed coal flow evenly across the pipe. In a first form, the invention comprises a plurality of static, lateral, linear diffuser elements comprising rows of protrusions or teeth spaced laterally across the coal flow path in the pipe, preferably in a staggered and overlapping relationship. In a second form, the diffuser elements are rotatably mounted across the coal flow path in the pipe, and may be rotated at different speeds and in different directions. The diffuser elements spaced across the coal flow path in the pipe may be supplemented by peripherally-mounted diffuser elements at the inlet of that portion of the pipe or housing to provide an angled pre-diffusion of the coal flow from the sides of the pipe toward the lateral elements extending across the interior of the pipe.

Abstract: In a delivery pipe for pulverized coal fines from a coal mill to a combustion chamber, a device for diffusing unevenly distributed coal flow evenly across the pipe. In a first form, the invention comprises a plurality of static, lateral, linear diffuser elements comprising rows of protrusions or teeth spaced laterally across the coal flow path in the pipe, preferably in a staggered and overlapping relationship. In a second form, the diffuser elements are rotatably mounted across the coal flow path in the pipe, and may be rotated at different speeds and in different directions. The diffuser elements spaced across the coal flow path in the pipe may be supplemented by peripherally-mounted diffuser elements at the inlet of that portion of the pipe or housing to provide an angled pre-diffusion of the coal flow from the sides of the pipe toward the lateral elements extending across the interior of the pipe.

Abstract: In a coal-fired power plant having an exhauster fan for delivering coal/air flow through a discharge chute to a combustion chamber and further having a riffle box in the discharge chute, a mixing device located in the discharge chute between the exhauster fan and the riffle box for causing heavy and light distribution regions of the coal/air flow from the fan to converge upstream of the riffle box, thereby mixing them into a more homogeneous flow. In a preferred form, the device comprises a plurality of concentric, inwardly-angled rings located in the discharge chute to cause the heavy and light distribution regions of coal/air flow to converge after passing through the rings.

Abstract: An improved vane of the type adapted for use in the classifier cage of a bowl mill type coal pulverizer. The improved vane is designed such that its lower end extends below the classifier cage inlet when the vane is mounted in the inlet. In a preferred form, the vane has a generally trapezoidal shape with a longer lower edge. The vane is additionally bent or curved over a major portion to direct coal tangentially toward the surface of the classifier cone.

Abstract: An improved coal pulverizer classifying system including a classifier cone extension to protect coal flow into the pulverizer from the annular fine-lifting airflow from the pulverizer throat. The classifier cone extension replaces traditional intermittent discharge structure, improving flow through the classifier system and reducing the disruptive effects of the discharge on the annular flow from the pulverizer throat. The pulverizer feedpipe outlet is located in the classifier cone extension, but above the throat of the extension to prevent interference between the feedpipe and the flow of coal through the extension. In a preferred form an adjustable clearance cone is mounted for vertical adjustment on the lower end of the feedpipe.

Abstract: An improved classifier cage for bowl mill type coal pulverizers which have been converted from stationary throats to rotating throats with reversed flow direction. The direction of the classifier vanes is reversed such that the rotational flow direction of coal/air from the rotating throat is generally maintained as it passes through the classifier cage into a classifier cone, rather than being reversed in "U-turn" fashion. A further improvement is made in the geometry of the classifier vanes to create a better downward and tangential redirection of the flow into the classifier cone.

Abstract: An inlet venturi for coal-side exhauster fan structure used to deliver pulverized coal to a combustion chamber. Generally, the inlet venturi has an axial length comparable to that of the exhauster fan inlet, resulting in a shallow, smooth transition angle from the venturi to whizzer ring or similar structure for guiding the coal flow into the center of the fan assembly. The inlet venturi includes a back plate or collar portion which prevents eddy effects and pressure drop between the venturi throat and the exhauster fan inlet, and further serves to accurately position the venturi in the exhauster fan inlet. The inventive inlet venturi structure additionally permits the removal of some or all of the "whizzer" structure commonly used on such fans, resulting in substantial savings in power needed to drive the fan.

Abstract: A self-cleaning coal bypass and debris separation grid assembly has a sizing/segregating grid for particulate material such as coal, and a debris bypass grid downstream to bypass the coal to a coal crusher and separate any debris which might damage the crusher. Clearing mechanisms are provided for both the sizing/segregating grid and the debris separating grid. The clearing mechanism for the debris separating grid is preferably a rotating clearing comb having arcuate fingers yieldably mounted to a rotating axle shaft. The arcuate fingers are preferably adjustably tensioned to the axle shaft.

Abstract: A vertically aimable tip for a pulverized coal nozzle used in the boiler areas of coal fired, steam generating facilities. The nozzle tip comprises box-like outer and inner housings which are pivotally mounted as a unit to the outlet end of a pulverized coal conduit. A box-like end housing having integral splitter plates is loosely mounted in the outer housing in conforming and contiguous abutting relationship to the inner housing to complete the pulverized coal flow path. An air flow path is defined by the spacing between the outer housing and the combination of the inner and end housings. The combination of the end housing and splitter plates is held in place by means by slots and locking keys or tabs to permit differential thermal expansion. The splitter plates are hardfaced and extend upstream into the interior of the inner housing.

Abstract: An air flow rate control device for a rotating or stationary vane throat in a bowl mill pulverizer. The air flow rate control device comprises an adjustable deflector mounted on the lower surfaces of the pitched vanes to provide varying air flow passage cross sections. In one embodiment the deflector comprises a flexible member whose shape can be varied using manual adjustment apparatus to alter the air flow passage cross-section.