Abstract: A method of breaking rock from a free surface which uses hydrofracturing to induce rock failure. Initially, a hole is cut in the rock face to a depth suitable for spalling by a high pressure water jet drill. Next, at the bottom of this hole a thin circular slot is hydraulically cut into the rock. The slot's circular axis is cut parallel to the transverse axis of the hole and the slot is made larger than the hole diameter. Following this step, a high pressure packer, with a high pressure tube passing through its center, is inserted into the drill hole. This packer is placed near the bottom of the hole above the slot and inflated. A fluid, like water, under high pressure is pumped down the hole past the packer into the slotted area. This high pressure fluid initiates a tensile fracture in the rock at the circular periphery of the slot. Tension is induced in the rock at this peripheral location due to the small radius of curvature existing there.

Abstract: A capacitance probe sensor device is disclosed which has a probe formed of KYNAR insulated wire spaced from an uninsulated metallic ground electrode. An oscillator and associated capacitance-resistance network connected to the probe serve to provide a linear output voltage proportional to the change of capacitance between the insulated wire and the ground electrode. The capacitance probe sensor device can be used in a number of applications. They include the measurement of water level, the determination of a liquid's flow rate, and the moisture content of soil.

Abstract: A method is provided for recovering energy from wasted coal by the steps of creating at least one channel through the wasted coal, igniting the wasted coal in said channel, subjecting said wasted coal, at least at said channel, to a negative pressure applied at a preselected point, connecting said wasted coal, at least at said channel, to a source of air remote from said preselected zone whereby air is induced through said ignited coal to burn said coal to produce hot gaseous products of combustion, and the hot gaseous products of combustion are drawn from said zone, and utilizing said hot gaseous products of combustion in a heat exchange relationship to recover the heat energy therefrom.

Abstract: In a transducer signal processing system wherein the output signal generated by a transducer (14) includes a nearly d.c., relatively large amplitude drift component (12), a higher frequency end point, data component (10) and a high frequency noise (hash) component (11), the drift and hash components are substantially eliminated by supplying the composite transducer output signal to a pair of parallel integrator circuits (28, 30) having different integration time constants. The faster integrator (28) passes the drift and data signal components, while attenuating the hash component, whereas the slower integrator (30) passes the drift component and attenuates the data and hash components. The output of the slower integrator (30) is subtracted from the output of the faster integrator (28) to provide a resultant signal containing essentially only the transducer data component.

Abstract: A fire protection system which senses the fire and actuates the dispensing of a fire suppressant without the use of electronics or electrical devices. This invention utilizes the process known as occlusion to storage large amounts of hydrogen gas in relatively small confined volumes. When an external heat source is presented to the system, such as that from a fire and/or explosion, the storaged hydrogen--via a metal hydride--is released and thereby builds up a pressure in its confined volume. This pressure is used to do work, namely moving a piston. After the piston moves a predetermined distance, it actuates the release of a gas which in turn fluidizes a dry powder suppressant which is dispensed via hoses and nozzles to the same fire and/or explosion. After the fire is suppressed, cooling of the metal hydride occurs which causes the hydrogen gas to reenter the metal hydride and the pressure in the piston to decrease.

Abstract: A battery powered paging and intercommunication system for application in a mine or other environment where it is necessary to conserve battery power comprises a plurality of transceivers electrically coupled to a common pair of signal lines. Each of the transceivers includes a push-to-talk switch for applying voice signals onto the lines as well as a push-to-page switch that amplifies received voice signals for reproduction through a loudspeaker. Each transceiver also includes dual tone multifrequency (DTMF) encoder and decoder circuitry for addressing a preselected transceiver on the lines for paging. A timer circuit within the transceiver limits the period of time the transceiver limits the period of time the transceiver is in the paging mode to reduce battery consumption. As a system check during paging, the called transceiver generates "beep-back" signals on the lines indicating to the calling transceiver that it is receiving paging signals.

Abstract: A calibrateable light ray scattering reference rod utilized in a light scattering dust monitor. This light ray rod scatters an amount of light equivalent to a given concentration of dust. Adjustability is provided so that several concentrations of dust can be represented. This adjustment is accomplished by moving a threaded opaque slug axially inside the translucent rod.

Abstract: The use of a catalytic coating which acts to combine both the heat source and heat-transfer mechanism for a working fluid, such as that used in an external combustion engine. Maximum heat exchange is accomplished by the direct bonding of the coating, per se, to the engine head with a compound of catalytic agents which confines heat of combustion directly thereto. The preferred embodiment of the engine head surface may be finned or otherwise enlarged to provide for an increased surface area necessary for the heating of the engine head. This means of surface combustion results in a highly fuel-efficient engine and/or heat source with very low exhaust pollutants.

Abstract: Instrumentation that can be lowered into an underground cavity to measure the dimensions of the cavity and also, as an added option, the ability to take photographs of the area of interest. The basic structure making up the preferred embodiment has a mounting frame with a television camera, a light beam assembly having two separate aligned light sources, and a mechanism to raise/lower the frame and also to tilt the light beam assembly. Above the ground is an appropriate readout unit which relates the angle of tilt for one of the light beam sources to a value of an electrical signal. To determine the distance from the aligned light source to the cavity surface, the light beams are superimposed upon one another to form a spot on the surface whose distance from the sources is to be measured. This spot is observed on the television camera and the signal magnitude (voltage) corresponding to the angle of tilt of the light source noted.

Abstract: A pressure vent for an explosion proof container. The vent allows a high flow rate of gases to pass from the container while arresting flames and cooling exiting hot gases therein. This precludes the build-up of high peak pressures inside the container. Structurally the vent has a protective cover mounted to the container by a knife hinge on one side and closed by imbedded magnets on the opposite side. In addition, the vent has multilayered material mounted in the same container opening near the interior of the container. A layer of porous stainless steel foam with multiple layers of stainless steel screen is used for this vital multilayered material. The optimum embodiment is obtained by preselecting a relationship between the free space volume inside the enclosed container, the number of layers in the prefilter section of the vent, and the cross sectional area of the vent.

Abstract: A sonic agglomeration system wherein high sound intensity and resonance are maintained with a low power input. These functions are attained through the use of a chamber feed-horn design that promotes resonance and maximized the efficiency of sound transfer between a sound producing compression driver and a resonant chamber. A digital controller maintains efficient resonance in the chamber and an efficient agglomeration rate constant by making adjustments in the frequency, sound amplitude and nuclei injection rate of the system.

Abstract: A longwall mining machine comprises a rotatable cutting head having a configuration in the form of an equilateral triangle viewed along its axis of rotation and formed with a continuous auger along the outer surface of the head. Cutter bits are located on apexes of the auger. The cutting head is mounted on a boom adjacent the longwall and is geared to produce an eccentric Cardan motion to the head causing the cutter bits to follow a substantially square trajectory in a plane normal to the axis of rotation of the head. Production of coal dust is minimized by deep linear vertical and horizontal cuts extending downwardly from roof to floor. During rotation of the head, cut coal is augered outwardly from the longwall and dropped into a conveyor for removal to a collection area.

Abstract: An apparatus and method that gives very accurate measurements which allow one to determine the values of ionic activities of aqueous electrolyte solutions. To obtain these accurate measurements, moderately accurate measurements of vapor pressure differences between pure water (or a reference liquid) and the aqueous electrolytes is first obtained. A container with a known solution of nonvolatile electrolyte in water, i.e., a solution of known composition, is connected to one side of a differential pressure transducer, the other side of which is connected to a second container with a deionized double distilled water. Next, the gas in the containers and dissolved in liquids is evacuated by using a mechanical pump and the containers are immersed in a temperature controlled medium. At this point in time, the differential pressure transducer measures the difference in pressure.

Abstract: A rotatable mounting block with a coal cutter bit which reduces the amount of wear to the bit. The cutter bit is fixed within the bore of a bit holder and moves in unison therewith within the mounting block. Positive rotation of the holder/bit is provided by a ratchet sleeve and pawl which interact with spiral slots on the lower extending end of the bit holder. The pawl prevents rotation of the ratchet sleeve in one direction (downward) so that the cutter bit will rotate during movement into the mounting block's bore as inwardly facing sleeve teeth are cammed in the slots of the bit holder. On the upward stroke of the bit/holder within the mounting block, the ratchet sleeve is free to rotate as a strong Belleville spring--also in the mounting block--forces them upward to the original position.

Abstract: A borehole packer used with the water infusion system to control the movement of methane gas in an underground coal mine. A non-sparking plastic pipe or mandrel is mounted in each of a series of previously drilled generally horizontal boreholes. Normally this pipe is sealed by an encircling packer in the form of an expandable envelope. The mandrel and envelope are put in each borehole to a depth of about 110 to 185 feet with about 15 feet near the end away from the borehole entrance being opened. The flexible expandable envelope extends along almost all of the length of the hollow mandrel. In the volume between the outer surface of the mandrel and the envelope a hardenable fluid grout under pressure is pumped. As the grout fills this cavity the packer's flexible surface expands within the borehole until it forms a tight seal therewith. Because the grout is in an initial fluid state, it is flowable when forced into the packer and it can flow around irregular borehole surfaces.

Abstract: A self-contained, closed circuit breathing apparatus having a balanced breathing resistance system is provided by an apparatus comprising an inhalation conduit and an exhalation conduit, a mouth connection communicating with said conduits for making connection with the mouth of the operator, an inhalation check valve and an exhalation check valve on either side of said mouth connection providing uni-directional flow through said inhalation and exhalation conduits, respectively, a chemical canister connected across said inhalation and exhalation conduits, a pre-canister storage container communicating with said exhalation conduit, said pre-canister storage container being provided with a uni-directional impedance component comprised of a resistance means for allowing one part of the exhaled air during exhalation to pass into the pre-canister storage container and the remainder to pass through said chemical canister into a post-canister storage container and a uni-directional check valve permitting essentially

Abstract: An improved discriminating circuit breaker system for use with an electrically grounded direct current power distribution system. A three-tier safeguard system is provided to insure proper operation of the breaker should a fault occur. The basic components include the electrically operated circuit breaker and a control circuit therefor. The control circuit sends a control signal to the breaker to operate it depending on whether a illegitimate load is detected on the power distribution system. This detection process utilizes: a pilot wire through which any control signal flows; an alternating current (a.c) signal generator to superimpose such a signal on the transmission line; a current detector to sense the a.c. level and produce a control signal if its current value exceeds a maximum level; a voltage detector to sense the voltage level of the a.c.

Abstract: A passive explosion barrier is provided for use in mining operations in suppressing mine explosions. The barrier basically comprises a receptacle or tub which contains an explosion suppressing substance, such as water, and is mounted on a frame adjacent to the roof of the mine. The tub includes a pair of integral support lips at the front and rear edges thereof which are beveled at the sides and which constitute the sole support for the tub. In operation, wind from an explosion will cause the lip disposed toward the explosion to distort and curve inwards and disengage from the frame so that the tub falls, pivoting about the other lip. In an alternative embodiment, the sides of the tub are more flexible than the lips of the tub, and distortion of the sides in response to wind forces causes disengagement of the lip facing the explosion.

Abstract: A self-recocking actuation device. One possible use for it is in conjunction with a pneumatic fire protection system. This invention employs the process known as occlusion to store large amounts of gas in a small volume. Metal hydrides in a chamber are used to store hydrogen in the disclosed preferred embodiment. Upon the application of heat--from a heat source like a resistance heater--the charged metal hydride releases its hydrogen (H.sub.2) in a chamber having only one exit opening which empties into a sealed bellows. This bellows contacts a piston located in another chamber wherein a biased resetting spring is provided to normally maintain the piston in contact with the bellows. As the pressure from the H.sub.2 gas builds up, it overcomes the biased spring to move it and the piston along with an associated pin or other actuator.

Abstract: A slideboard for underground mine face ventilation which acts as an extension of a line brattice. When used, the slideboard is advanced towards the working face of the mine to provide an inlet for clean air and an outlet for exhausting gases laden with dust particles. The slideboard has a frame supported on and slideable with respect to the ground as it is advanced along with a continuous mining machine. At the upper portion of the slideboard frame are a series of halflooped hoses which provide a flexible seal with the roof. The main supporting frame is rigid and is formed by a series of vertical and horizontal members whose narrower edges face into the air stream to reduce air friction and increase rigidity. Near the center of the slideboard a rib strut and outrigger provide lateral support and a sliding surface and pivot point. The base of the slideboard is trapezoidal for structural reinforcement; and a plywood gusset in the panel place provides additional reinforcement.