摘要:
A mine prop provided with an overpressure valve of large flow-through section which opens when excessive forces suddenly act on the prop to discharge pressure fluid from the interior of the prop. The overpressure valve comprises a hollow cylindrical housing forming at one end a valve seat communicating with the fluid-filled inner space of the prop and a valve member axially guided in the housing for movement between a closed position engaging the valve seat and an open position. The fluid-filled space of the prop communicates with channels leading to the outside of the prop. The valve member is normally maintained in the closed position by a gas pillow under high pretension confined in a pressure space delimited peripherally by the wall of the valve housing and at opposite ends respectively by the valve member and a plug fluid tightly mounted in and closing the other end of the housing. The valve member and the plug are both formed from metal and are both provided at facing ends with annular slender sealing lips of triangular cross-section tapering toward each other, the outer surfaces of which are pressed into engagement with the inner peripheral surface of the housing by the pressure of the gas pillow.
摘要:
The pressure measuring device has a housing in which a pressure chamber is located in a pin extending freely in the interior of the housing from a base. The pressure chamber wall is deformable elastically under an applied pressure. In the free end portion of the pin a magnetoresistive sensor is mounted which is moved with the chamber wall in a displacement occurring because of pressure changes in the chamber and thus is displaced relative to a permanent magnet. The magnet is mounted slightly transversely in the end portion of a compensating sleeve which surrounds the pin with wall contact. The change of the magnetic field at the sensor on displacement causes a proportional resistance change of the sensor so that an electrical signal proportional to the pressure change is generated which is a measure of the pressure. An amplifier for the signal from the magnetoresistive sensor can be mounted inside the housing adjacent the permanent magnet or the magnetoresistive sensor. Also advantageously the space between the housing and the compensating sleeve can be filled with insulation to further reduce temperature compensation requirements.
摘要:
A hydraulic mine prop comprises a cylindrical top ram portion and a bottom ram portion which is telescopically engageable in said top ram portion and has an upper piston portion in sliding sealing engagement with the interior of said top ram portion. A ram head closes the top of said ram portion and a valve seat body is disposed between the ram head at a spaced location therefrom adjacent the top of the top ram portion and defines a vent space therebetween. The valve seat body also encloses a pressure space between itself and the piston and a passage is defined through the valve body within a valve seat portion thereof which communicates the pressure space to the vent space. The passage is closed by a spring-biased valve which may open against the biasing force of the spring. The construction includes one or more passages extending through the valve seat and through various generally radially extending passages defined in the body from the pressure space to the vent space and additional passages which are defined outwardly from the vent space to the atmosphere. The construction also includes a ring around the top ram portion having an annular passage which is communicatable through a port or bore of the top ram portion cylinder to a pressure holding valve space which is closable by a rotatable globe valve.
摘要:
A canopy and shield structure for supporting a shield adjacent a working face in a seam-like mine deposit, comprises a floor skid which is connected through an extensible and retractable prop at the working face end to the working face, and of a canopy, which is adapted to be positioned in parallel relation to the roof strata. The working space is covered at the waste removal end by a shield which includes a lower portion pivotal on the floor skid, and an upper portion which is rigidly connected to the canopy at the opposite end of the canopy from the working face end. The shield is connectable to an extensible and retractable prop and a lemniscate guidance mechanism, so that the upper part of the shield may be moved upwardly and downwardly along its longitudinal axis. The upper part also carries an opening for the passage of a blast pipe which is supported on roller means carried by the canopy.
摘要:
A chain bucket conveyor for an underground excavation has a substantially U-shaped forward conveyor part at the side of the sole and open toward a roof, a return conveyor part at the side of backfilling and closed in a substantially channel-like manner, wherein the return conveyor part is normal to the forward conveyor part, and means for transporting the chain from one to the other of the conveyor parts and including actuating stations, a rotary chain wheel having chain pockets and arranged at the actuating stations rotatable about an axis which extends toward the roof and backfilling and is located in a vertical plane transverse to the longitudinal direction of the conveyor, and a conical surface narrowing toward the roof and having an axis coinciding with the axis of rotation of the chain wheel.
摘要:
A method and a system are disclosed for supporting an overburden. A single-section or telescoped multi-section longitudinally slit prop casing of light sheet material such as cardboard or metal has a fabric bag installed in it. When the casing is erected the bag is filled with a slurry of hardenable substance which, upon hardening, forms in the bag a column which supports the overburden. The casing may be left in place or it may be removed for re-use.
摘要:
A method of and an arrangement for loosening, loading and transporting of stratified minerals includes a single continuously rotating and forceably guided pulling organ, a plurality of loosening elements integrated in the pulling organ in its working run extending in a longitudinal direction of a longwall, and a plurality of transporting elements also integrated in the same single pulling organ at its transporting run located behind the working run at a back filling side, wherein the loosening elements perform loosening and loading functions, whereas the transporting elements perform the transporting functions in an opposite longitudinal direction of the longwall.
摘要:
A shut-off valve has a sealing cone which in a closed position of the valve abuts against a conical sealing seat and is formed as a part of a cylindrical throttling piston, a sealing surface of the sealing seat cooperates at its one end with a cylindrical receiving opening for the throttling piston, and the outer diameter of the throttling piston is selected with respect to the inner diameter of the receiving opening so that a throttling gap is formed between the receiving opening and the the throttling piston.
摘要:
A rock anchoring arrangement for use in tunnel and mine constructions comprises an elongated anchoring rod insertable in a bore formed in a rock formation, and a supporting plate arranged in contact with the rock formation at the open end of the bore. The anchoring rod includes a leading end portion fixable at the bottom of the bore, a trailing end portion fixable at the open end of the bore, and a smooth intermediate portion of a cross-sectional area smaller than those of the trailing end portion and the leading end portion. The anchoring rod is fixable by an adhesive within the bore at the leading end portion and at the trailing end portion whereas the intermediate portion is surrounded by an adhesive-repellent material to prevent the sticking thereof to the adhesive.
摘要:
A shield timbering frame for timbering mines adjacent a mining face, comprises a horizontal floor-engaging skid and a breaking shield extending obliquely over the skid which is connected to the skid by a pair of longitudinally spaced, lemniscate guide rods. A roof cap member has an inner end which is pivoted to the upper end of the breaking shield and it is also braced by a piston and cylinder combination which is articulated to the breaking shield intermediate the length thereof and to the roof cap intermediate its length. At least one hydraulic ram is mounted on the skid and is engaged with the roof cap between the connection of the roof cap to the breaking shield and the connection to the additional support. The hydraulic ram is madeup of at least three telescopically interengageable extensible and retractable parts and includes pressure valve means to provide a substantially equal support pressure on the roof cap in various positional orientations of the roof cap.