Abstract: A valve device takes the form of a multi-part cartridge with a hollow stepped housing containing a stepped rod. A control piston at one end of the rod is opposed by the force of a main spring in a main chamber remote from the control piston. A valve closure member is axially displaceable relative to the rod. The valve closure member is normally held against a valve seating but pressure on the control piston displaces the rod and causes the valve closure member to be lifted from its seating via stop faces. An auxiliary chamber in the housing leads via a connection to some consumer appliance and forms, the downstream side of the valve. A compensating piston on the rod member opposes a face of the valve closure member open to the auxiliary chamber. A further spring in the auxiliary chamber holds the valve closure member on its seating. The valve can open independently of the control piston should the pressure on the upstream side of the valve exceed the consumer pressure.

Abstract: An electro-hydraulic control system for a mineral mining installation has a series of valve blocks, each contain a number of valves which are operated in dependence on electrical signals to cause hydraulic appliances of roof supports to operate. To allow emergency operation, when there is a power failure or when the control system fails or is otherwise inoperative, further manually operable valves are connected by a flexible, multi-core connecting cable to the valve block of the associated support. The emergency control valves can operate hydraulically controllable direction control valves of the control system and by-pass the electrical controls. The support can then be controlled purely hydraulically, at least in its main functions, using the emergency device.

Abstract: A valve device has a multi-part housing containing a servo-valve with a stem which is axially displaced to operate the valve and an electromagnet with a rod-like armature which is axially displaced when the electromagnet is energized. A pivotable lever translates the axial movement of the armature to the stem. For adjustment purpose, an adjustment member is in screw-threaded engagement with the lever remote from the stem. The armature is locked for rotation with the adjustment member. A regulator at the opposite end of the armature to the lever and accessible from the exterior serves to enable the armature to be partially rotated for effecting the adjustment.

Abstract: Tertiary alcohols with 4 or 5 carbon atoms are produced by reacting an isoolefin-containing hydrocarbon stream with water in the presence of a strongly acidic, solid hydration catalyst in such a way that each of the two process streams, the hydrocarbon stream and the process water, is cascaded through several reactors connected in series such that one process stream is fed to one end of the line of reactors and the other process stream to the other end of the line of reactors, and the two process streams pass through the line of reactors in opposite directions, while they pass through the individual reactors as parallel currents.

Abstract: The invention relates to a method for the simultaneous actuation of a plurality of hydraulic consumers by means of intrinsically-safe electro-hydraulic valves. The consumers are connected by hydraulic directional control valves to a pressure line and/or a return line. These hydraulic directional control valves can be connected in a predetermined manner, via pre-control valves to a control line. The pre-control valves are pressureless, and possess electro-magnets with a current consumption of less than 50 milliamps. By connection of a series-connected electro-hydraulic directional control valve means, the pre-control valves are connected to the control line, and at the same time are hydraulically locked.

Abstract: A hydraulic control arrangement comprises a first hydraulic ram, a second hydraulic ram, and a hydraulic control circuit associated with the first and second hydraulic rams. Each of the hydraulic rams has a cylinder, a piston reciprocable within the cylinder, and a piston rod fixed to the piston. Each of the hydraulic rams has a cylindrical working chamber and an annular working chamber positioned on opposite sides of its piston. The piston rod of each hydraulic ram constitutes the cylinder of a respective metering ram, a respective metering piston being reciprocable within the cylinder of each metering ram to define a metering chamber therewithin. The hydraulic control circuit includes a line, which interconnects the two metering chambers, and a hydraulic valve positioned in a hydraulic fluid supply line leading to the cylindrical working chamber of the second hydraulic ram.

Abstract: A process for producing a lower aliphatic alcohol by splitting ethers whereby ethers are reacted at an elevated temperature and pressure with an excess of water in the presence of acidic hydration catalysts is disclosed.

Abstract: A method is provided for the continuous production of isopropanol and secondary butyl alcohol by catalytically hydrating the corresponding aliphatic olefin in an elongated reaction vessel in which co-product by-product dialkyl ether is separated from the reaction product and recycled to the reaction mixture being introduced therein at a point between the olefin feed inlet and the product outlet about 5 to 30 percent of the distance before the product outlet.

Abstract: Apparatus for controlling the working stoke of the hydraulic props of a mine roof support unit is disclosed. The control apparatus comprises a control valve whose input side is connected to a hydraulic pressure line, and whose output side is connected to a working chamber of each of the props via a respective supply line. A sequence valve is provided in the supply line leading to one of the props. The sequence valve is such as to open the associated supply line when subjected to a predetermined hydraulic pressure, this predetermined hydraulic pressure being at least approximately equal to the hydraulic pressure necessary to overcome the resistance to the working stroke of another of the props. The sequence valve has a tubular valve body, a valve closure element mounted within the valve body, and a valve seat positioned within the valve body. A spring is provided for biassing the valve closure element towards the valve seat.

Abstract: Methyl t-butyl ether and methyl t-amyl ether are produced by reacting methanol with isobutene and isoamylene, respectively, at a total methanol/isoolefine mole ratio of 1-1.2:1 in a series of reaction stages such that in the first reaction stage, the total amount of olefin component is reacted with as much methanol as is required to ensure that the methanol/isoolefine mole ratio in the first reaction stage does not drop to less than 0.65:1, and that the methanol concentration in the effluent stream does not exceed 0.4% wt. The residual amount of methanol is then fed either all at once to another reaction stage, or in portions to several additional reaction stages.

Abstract: A compact hydraulic control device for use with mining apparatus is composed of a housing block containing tappet-operated valves. A multi-part cam shaft serves selectively to operate the valves by displacing the tappets by manual control effected by external levers. To automatically restore the cam shaft back into a neutral position as a "dead-man's handle" restoring system use is made of a pair of piston and cylinder assemblies mounted as detachable cartridges in parallel locations within bores in the housing block and having push rods which act on a cam of the cam shaft under the action of hydraulic or pneumatic pressure medium.

Abstract: A mine roof support has a main roof-engaging structure 2 carried by hydraulic props 6 in known manner and an auxiliary roof-engaging structure at the front end of the main roof engaging structure. The auxiliary roof-engaging structure can be swung up and down and is itself of multi-part construction with one component 7 directly linked to the main structure and another selectively extendible forward component 8 mounted to the one component. One hydraulic piston and cylinder unit 9 is provided for swinging the auxiliary structure and for setting the structure against the roof and another such unit 10 is provided for selectively extending and retracting the forward component thereof. A hydraulic control arrangement 16-18 associated with the units ensures that when the forward component is being advanced the roof setting pressure acting on the auxiliary structure is automatically reduced.

Abstract: A roof support unit for a longwall mineral mining installation has a roof shield supported above a floor sill. A first hydraulic ram is provided for advancing the roof support unit. The roof shield is provided with a forward extension which is advanceable by means of a second hydraulic advance ram. A hydraulic control arrangement, which includes the two hydraulic advance rams is provided for controlling the advance of the roof shield extension in dependence upon the working stroke of the first hydraulic advance ram. The control arrangement is such that the amount of hydraulic fluid supplied to one of the pressure chambers of the second hydraulic advance ram is dependent upon the amount of hydraulic fluid expelled from one of the pressure chambers of the first hydraulic advance ram during the working stroke of the first hydraulic advance ram.

Abstract: A mine roof support has hydraulic props mounted between a floor sill and a roof bar which can be raised and lowered by extension and retraction of the props. A goaf shield is pivotably connected to the rear of the roof bar and is linked via levers to the floor sill. A hydraulic piston and cylinder unit is connected between the roof bar and the goaf shield. Apparatus serves to prevent damage to the support components, and especially to the unit which could be extended beyond its full stroke when the props are retracted to bring the goaf shield and the roof bar more or less into alignment. The protective apparatus is composed of a compact valve device operated by a member, such as a cam, to block the props from hydraulic pressure when the goaf shield and the roof bar assume a pre-determined angular disposition. Both the valve device and its operating member are disposed in a protected position within chambers formed inside the roof bar and the goaf shield adjacent the pivot connection therebetween.

Abstract: A hydraulic control system, particularly for controlling the operation of roof support props of a mine working, employs control devices operated manually to feed pressure fluid to the working chambers of the props to effect extension or retraction thereof. A two-state valve device is operated when the props are extended to ensure that the correct setting pressure is established. This valve device has a control piston which is actuated to cause the device to establish independent connection between the main fluid pressure line and the associated working chambers of the props charged with fluid by the initial operation of the control devices. The connection established by the valve device is maintained even if the control devices break connection between the chambers and the pressure line. When the correct setting pressure is reached, a further control piston of the valve device is actuated to break the connection established by the valve device ready for the next operative cycle.

Abstract: A hydraulic control system is provided for a mine roof support assembly constituted by a plurality of roof support units positioned side-by-side. The control system comprises a respective control valve assembly having a plurality of similar control valves each of which controls a respective hydraulic appliance associated with the corresponding roof support unit. Each control valve can be actuated optionally by an actuator mounted on either one of the two adjacent roof support units, or by either one of two actuating devices mounted one on each of said two adjacent roof support units. Each control valve includes two servo valves having a pair of first and second axially aligned servo-pistons which are separate and independently operable with respect to each other.

Abstract: In a mine installation which employs a winning machine moved back and forth along a guide in a working and coupled via shifting rams to roof supports, the invention provides a hydraulic fluid supply conduit system for supplying the pressure fluid for operating the shifting rams and the props of the roof supports. The system employs a first conduit containing fluid at a pressure of 300 to 400 bars for setting the props of the roof supports, a second conduit containing fluid at a pressure of 100 to 200 bars for use as a robbing aid during retraction of the props, a third conduit containing fluid at a pressure of 100 to 200 bars for operating the shifting rams and a common fluid return conduit. The conduits are laid along the working and the first and the second or third conduits are fed by separate pumps in a heading or gallery while the third or second conduit is connected via a pressure-reducing valve to the pump feeding the first conduit.

Abstract: Mining apparatus comprises a longwall conveyor and tensioning means for tensioning the conveyor in its longitudinal direction. The tensioning means is constituted by a plurality of hydraulic tensioning rams, each of which is mounted, in use, by means of pivot joints at each end thereof directly between the conveyor and a respective roof support unit of a roof support assembly. Each tensioning ram extends at an acute angle to the longitudinal axis of the conveyor. The tensioning rams are positioned in two groups, one in each end zone of the conveyor.