Abstract: A piston type pneumatic powered actuator (9) for operating a valve (10) of the expanding gate type wherein velocity of the piston-stem-gate drive train is maintained substantially constant in the latter stage of the actuator stroke. The actuator (9) includes an assembly of dual pistons (61,75) which are adapted to be driven by fluid pressure in one direction to operate the valve but are returned by spring means (66,67) when the fluid pressure is removed. A drive piston (61) directly connected to the actuator stem (23) is nested within a primary piston (75) which is not connected to the actuator stem (23) but moves the drive piston (61) when actuating pneumatic fluid is applied to the actuator (9). A stop (85) affixed to the primary piston (75) is adapted to cooperatively engage the actuator housing (40) to terminate the stroke of the primary piston (75) prior to termination of the stroke of the drive piston (61).

Abstract: Apparatus and a method are disclosed for reducing sulfate contained within a flowable material to hydrogen sulfide by the use of two stages of reaction. The flowable material is deoxygenated and then introduced into a first reactor which contains a sulfate reducing bacteria such as a Desulfovibrio or Desulfotomoculum. Hydrogen sulfide is removed from the first reactor and the remaining portion of the flowable material is subjected to a separating action to produce a supernatant component and a sludge component. The sludge component is reintroduced to the first reactor which is generally devoid of packing or support and the supernatant is introduced into a second reactor which is preferably in the nature of a supported film reactor. Mixed products including carbonate may be removed from the first reactor. The second reactor also contains anaerobic sulfate reducing bacteria. Hydrogen sulfide, low sulfate water and carbonates may be withdrawn from the second reactor.

Abstract: A high pressure sealing connection for sealing between coaxially aligned members (22, 10) which are connected by metal bolt means having a different coefficient of thermal expansion from the aligned members. The connection comprises a metallic sealing ring (40) having at its largest external diameter a curved arcuate peripheral surface 52 characterized by a center of curvature which is co-diametral with the center of the seal ring but may be of greater or lesser radius than the radius of the ring. At its inner periphery, upper and lower flanges (61, 62) extend inwardly and perpendicularly to the axis of the ring. The coaxially aligned members (22, 10) are provided with recesses defined by opposed internal frusto-conical sealing surfaces (41, 42) at their adjoining ends, each tapering inwardly from the end of the member to an annular shoulder (43, 44) in the bore of the aligned member. The frusto-conical surfaces (41, 42) are of equal taper in the range of 5 degrees to 20 degrees.

Abstract: A "fire-resistant" packing arrangement (30) for use with linear motion or rotary motion shafts (20) characterized by a stepped dual diameter packing chamber provided by successive enlargements of the stem bore (22). A primary packing assembly (31) disposed in the chamber section (20b) of smaller diameter and cross-sectional areas and located nearest the fluid pressure provides for sealing under normal temperature and operating conditions. A secondary packing assembly (32) in the larger diameter chamber section (20c) and fabricated of "high temperature" materials is adapted to maintain sealing effectiveness in the event of abnormally high temperatures.

Abstract: Systems for desulfurization of a flue gas containing fly ash including formation of a dry powder in a spray dryer absorber resulting from reaction of an alkaline aqueous feed and the flue gas. The dry powder is collected and a specifically selected fraction is recycled to a feed preparation subsystem for inclusion in the aqueous feed. Selective recycle is based on physical or chemical properties and, for example, large diameter and dense particles provide enhanced reagent utilization compared to smaller and less dense particles.

Abstract: A cable tension control device for an electrically powered mine vehicle is disclosed. The vehicle is of the type having an electric trailing cable wound on a cable reel mounted on the vehicle. The cable reel has a motor for rotating the reel in the direction for taking up the cable as the vehicle moves toward a power source and for preventing freespooling of the reel as said cable is unwound as the vehicle moves away from the power source. The device includes a sensor for measuring the amount of electric cable on the reel and utilizes this sensed amount of cable for controlling the drive torque of the motor in direct proportion to the amount of cable sensed on the reel. The same sensed amount of cable is used to control the braking torque developed by the motor when the motor is being driven by the reel as when cable is being pulled off during movement of the vehicle away from the power source.

Abstract: A dual stage hydraulic actuator (9) for actuation of an expanding gate valve (10). The actuator is mountable to the valve housing and comprises a housing 40 which defines a piston chamber 41 and a primary piston (61) slidably received therein. An actuator stem (23) connects the piston (61) to the valve gate assembly (20). A secondary piston (77), of smaller piston area than the primary piston (61), is slidably received in a piston receiving bore (75) which is formed in the fluid receiving face of the primary piston. A piston rod (80) connects coaxially with the piston (77) and extends through the end (52) of the actuator housing. The actuator is responsive to hydraulic fluid pressure which when applied through an inlet (71) of the actuator housing to one side of the pistons (61, 77) drives the actuator stem and gate assembly to an operational open or closed position of the valve.

Abstract: A mining machine is disclosed which has a vehicle body with a first end thereof having a boom pivoted for up and down rotational movement about an axis extending transversely of the vehicle. A cutter head is carried by the boom and a conveyor is mounted on the vehicular body to carry away material cut by the cutter head. A dust collection system is mounted on the boom and vehicle body to convey dust away from the cutting head area. The dust control system has duct work associated therewith which includes a generally rectangularly intake duct section associated with the boom and a generally rectangularly fixed duct section mounted on the vehicle. A transition section connects the intake and the fixed duct sections.

Abstract: A crossover seal assembly (44) for sealing the annulus between a well casing (16) and tubing head (22). The assembly includes spaced pairs of upper and lower metal seal rings (60 and 72, 108 and 120) having matching frusto-conical wedging surfaces (70 and 74, 118 and 122) which interact when an axial compressive force is applied to thereby effect a controlled radial expansion of the seal rings to sealingly engage the inner and outer cylindrical surfaces (48, 47) of the tubing head (22) and well casing (16). The axial compressive force is mechanically applied by a plurality of holddown lock screws (90) which interact through tapered conical tips (94) to energize the crossover seal assembly (44).

Abstract: A suspension system for an operator's compartment of a mine vehicle is set forth. The mine vehicle is of a type that has a body and operator's compartment positioned adjacent to the body. A guide is attached to the body of the vehicle and a rail is attached to the operator's compartment. This guide and rail arrangement slidably connects the operator's compartment to the body. The guide and rail are arranged to permit the operator's compartment to independently move upward and down in relation to the body. The rail is located in a central portion of the operator's compartment to minimize the angular displacement of the rail with respect to the guide upon rotation of the operator's compartment. This ensures free upward and downward motion of the operator's compartment with respect to the body of the vehicle.

Abstract: Method and apparatus for controlling DC traction motors on opposite sides of a vehicle, particularly a mining machine, by means of an SCR converter. The motors are accelerated while controlling the firing angles of the SCR's such that the current and voltage supplied to the motors increase along ramps until desired normal operating values of voltage and current are reached with the voltage across the series-connected motors being of a substantially greater value than the value it would be if the motors were connected in parallel. In contrast to prior art systems, the traction motors are maintained in a series-connected configuration during normal, essentially steady-state operation; while the voltage across the motors is maintained at said substantially higher value. When one of two drive wheels connected to the traction motors is slipping, the motors are connected in parallel to increase torque with a corresponding decrease and increase in voltage and current, respectively.

Abstract: An expanding gate valve (10) provided with a piston type pneumatic powered actuator (40) for opening and closing the valve wherein the actuator piston (54) is adapted to be driven by fluid pressure in one direction to operate the valve but is returned by spring means (63, 64) when the pressure is removed. The actuator includes a hydraulic choke means (71) comprising a hydraulic piston (80) and cylinder (72) wherein the hydraulic piston is fixed to the actuator stem (23) and is provided with an orifice (89) which imposes a constant velocity control on the actuator stroke by producing a throttling effect on the hydraulic fluid moving from one side of the hydraulic piston to the other. The hydraulic cylinder (72) is filled with a fluid which maintains substantially uniform viscosity in the range of minus 40.degree. Centigrade to 204.degree. Centigrade whereby the valve is adapted for consistent operation during rapid cycling conditions.

Abstract: Method and apparatus for detecting deterioration of a replaceable liner in a pump transporting an electrically conductive fluid medium. A conductive component is isolated, during normal operation, from the conductive fluid medium by the electrically insulative liner. The conductive component is positioned at a predetermined location relative to the liner such that upon a selected degree of wear of the liner, an electrical circuit is completed upon contact of the fluid medium and the conductive member.

Abstract: A block valve (10) for selectively establishing and selectively blocking communication between a pressurized fluid supply (30), a fluid actuated device (DHSV) and a reservoir (35). The valve comprises a valve body (41, 42) with an inlet (81), an outlet (82) and a bleed port (83) and first and second piston-type plunger elements (61, 71) slidably mounted in piston chambers (51, 52) formed in the bore (43, 45) of the valve body. The second plunger element (71) is slidably mounted on the first plunger element (61) in sleeved relation therewith. Both plunger elements (61, 71) are continuously urged by springs (66, 75), respectively, to a first operating position wherein communication between the ports (81, 82, 83) is blocked by seal means (94, 95, 96) and blocking means (64) mounted on the plunger elements.

Abstract: Propellers including blades affixed to a hub which provide generally axial flow of a fluid medium through the blade area. The blades are formed from cylindrical segments and include a generally straight leading edge and a generally convex trailing edge.

Abstract: A pressure energized mechanically preloaded packing assembly (48, 68) of a high pressure gate valve (10). The packing assemblies are positioned in an annular space about the valve stems (36, 64) for sealing between the valve stems and bonnet (38) or valve body (12). The packing assemblies include an energizer ring (78) which is positioned within the annular space having an outwardly facing precision cut frusto-conical end surface (82) relative to the flow passage (16, 18) of the valve. A plurality of Belleville springs or spring washers (98) with a generally frusto-conical shape are positioned adjacent and in concave relation to the outer end (82) of the energizer ring. The cone angle of the spring washers are smaller than the cone angle of the energizer ring. The packing assembly further includes at least one packing ring set positioned outside the spring washers (106, 108) which includes a stack of plastic packing elements (110) which are sandwiched between a pair of retainer rings (112, 114).

Abstract: A valve seat structure adapted to be positioned within each annular seat pocket (37, 36) which is formed about the flow passage (12, 13) adjacent the valve chamber on both the upstream and downstream sides of the gate element of a gate valve. The valve seat structure comprises a metallic seat ring (40) which fits snugly within the seat pocket (36, 37) but has an axial dimension which exceeds the depth of the pocket. The seat ring is formed with an annular notch (49, 50) in the outer corner of the ring at its rear face (48) for accommodating a resilient O-ring (66) therein. In its front face (47) the seat ring is provided with an annular groove (51) coaxial with the ring axis and provided with serrated side walls (51a, 51b). A plurality of passages (55) are formed in the ring with equiangular spacing and extend from the face groove (51) to the corner notch (49, 50).

Abstract: A valve (10) having an expansible gate assemblage of ported juxtaposed gate and segment members (18, 19) which are movable into sealing engagement with upstream and downstream valve seats (28) about the flow passage (12, 14) in the open and closed conditions of the valve wherein the valve includes pressure relief means which relieves excessive pressure in the valve chamber (11) into the upstream flow passage (12) when the environment in the chamber reaches a preselected temperature with the valve retaining capability of providing an upstream seal in the event of subsequent downstream leakage. The pressure relief means is installed in the segment member (19) of the gate assembly and comprises a passage (43) extending from the port (16) through the segment to the sealing face (25) of the segment member at a location which is exposed to the upstream flow passage (12) in the valve closed condition.

Abstract: A method is set forth for controlling the orientation of an articulated boom of the type having a first portion and a second feed arm portion such that the first portion remains parallel to a predetermined position during movement of the articulated boom. The method utilizes a computer which senses the angular position of the various parts of the boom in a total of five directions and computes the required angular position of the feed arm to maintain it parallel to a set position as the boom is moved in any direction. Various hydraulic servovalves are utilized to control the flow of hydraulic fluid in a manner to maintain parallelism within 1/2.degree. with the referenced position.

Abstract: Discharge electrodes for use in electrostatic precipitators. In preferred form a discharge electrode is formed of a pair of body elements arranged in a partially overlapping relationship. The overlapping structure is such that a longitudinally extending support portion is formed in the lateral intermediate portion of the electrode. To each side of the support portion a web portion is formed which includes one of the body elements extending the full lateral extent of the web portion and the other body element extending only part of the lateral extent of the web portion. The body element which extends on each side of the support the full lateral extent of the web portion, also extends to form the corona discharge portion on that lateral side of the electrode.