Abstract: High-pressure liquid is controlled for delivery to nozzles disposed near cutting tools or on the periphery of a shearer drum for a longwall mining machine. The shearer drum includes a central shaft which is extended to project from a support arm for the drum containing drive gearing to rotate the drum. The shaft rotates in the same direction and speed as the drum. The extended end of the shaft is used to support a live seal by which high-pressure liquid is introduced to a central bore in the shaft. Between the live seal and the support arm for the drum, there is provided a casing that does not rotate with the shaft and includes sector recesses in the bore thereof to supply liquid to separate bores in the shaft for controlling the discharge of liquid from valves. The valves are separately controlled by the liquid pressure in the sector recesses so that only nozzles directed to the coal face receive the pressurized liquid.

Abstract: A high-pressure ball valve includes a valve housing with a bore that sealingly receives a cylindrical extension of a valve member. An inlet bore extending to the bore in the valve housing has a bottom seat against which a ball can seal off the inlet bore. The cylindrical extension has a pocket to receive the ball while engaging a stem that extends through a bore in the valve member against a piston of a single-acting piston and cylinder assembly. An outlet bore extends in the valve housing to the bore therein for delivering the fluid passing into the housing from the outlet bore.

Abstract: A cutter drum assembly for longwall mining machines incorporating means for spraying trickle water onto the face area being mined as the cutter drum rotates. This requires valving for supplying high-pressure liquid to only those nozzles adjacent the face area as the drum rotates. In accordance with the invention, the valving takes the form of individual valves spaced around the drum, the valves being actuated by a relatively low-pressure control medium (i.e., a liquid) which obviates the necessity for the close tolerances and rigid sealing requirements of prior art devices where high-pressure liquid valve assemblies were built into the rotary connection between a support shaft and the drum which rotates about it.

Abstract: A fluid coupling for interconnecting a liquid-conveying duct in a shaft element to a duct in a hub element, the two elements being rotatable relative to each other. The shaft element has a central passageway subjected to fluid under high pressure and has an enlarged-diameter end communicating with a smaller-diameter portion. The end of the large diameter portion of the shaft element remote from its small diameter portion is subjected to fluid under high pressure in said passageway; while the opposite end of the large diameter shaft portion is subjected to a sealing fluid. The pressure of the sealing fluid is always greater than that of the high-pressure fluid, with the result that the high-pressure fluid will not enter the chamber filled with sealing fluid to decompose it and form an emulsion.

Abstract: A rotary fluid coupling for conveying fluid from a stationary shaft to a hub rotatably mounted on the shaft, or vice versa. The coupling is characterized in having a shaft provided with an axial passageway extending therethrough, one end of the passageway being connected to a source of high pressure fluid and the other being connected to a source of high-viscosity sealing fluid (e.g., a lubricant). A piston in the passageway separates the high-viscosity sealing fluid from the high pressure fluid, the latter being conveyed to the surrounding hub through radial passageways formed in an enlarged diameter portion of the shaft. The high-viscosity sealing fluid is applied to both ends of the enlarged diameter portion of the shaft to form a seal which prevents escape of the high pressure fluid.

Abstract: A labyrinthine mechanical seal in a bore of a casing for a rotatable shaft which is substantially free of axial forces and mounted for axial movement while carried by bearings in the casing. The seal includes a first group of discs arranged in an axial spaced-apart relation on the rotatable shaft and a second group of discs arranged in a non-rotatable manner at axial spaced-apart locations in the bore of the casing to extend around the shaft and mesh with the first group of discs in a manner of a labyrinth. The axial clearances between the groups of discs is 0.2 millimeter or less and the radial clearance between the groups of discs is only slightly greater than the radial clearance in the bearings. The discs are resilient and consist of hardened steel. Alternatively, the discs of one of the groups consist of hardened steel and the other consists of bronze.