Abstract: A fuel-fired fluid heating appliance, such as a gas-fired boiler (FIG. 1) is provided for heating a fluid such as water circulating in a central heating system. The boiler includes a flue 4 for discharging the combustion products, e.g. exhaust gas, to atmosphere by way of a heat exchanger 8 incorporated within a portion 6 of the flue 4 external of the boiler housing 1. The heat exchanger 8 is provided with an inlet 16 to receive water from a return flow pipe 36 and an outlet 17 to discharge the water to the inlet 35 of the boiler primary heat exchanger 3. The heat exchanger 8 (FIG. 2) is provided with a number of ducts 18 along which the exhaust gas travels to transfer its heat to the water circulating within compartments 29 to 33 within the heat exchanger housing 15. The external portion 6 of the flue 4 is disposed at an angle of 20.degree. downwardly to the horizontal so that any exhaust gas condensing in the heat exchanger 8 flows down the flue base 9 to a discharge spout 10 and collector weir 11.

Abstract: An improved magnet assembly for a magnetic pipeline inspection vehicle in which the assembly is rigidly secured on the body of the vehicle which is ferromagnetic and provides an annular magnetic return path between magnetic pole members formed of permanent magnets and flexible bristles or foils.

Abstract: A process for the recovery of heat from the gas leaving a unit for the thermal hydrogenation of an oil feedstock, which process comprises quenching the gas with a quench liquid in a quenching zone in which all the internal surfaces thereof are irrigated by the quench liquid and passing the cooled gas and quench liquid to a heat recovery unit in which all the surfaces thereof in contact with gas are irrigated by the quench liquid.The process is particularly suitable for the recovery of heat from the gas leaving a fluidized bed hydrogenator.

Abstract: An inspection device detects flooding in a hollow structural member such as the leg of an oil or gas rig so as to detect the presence of through wall cracks in the member. The device comprises an ultrasonic transducer for transmitting a pulsed beam of ultrasonic sound to pass through opposing faced walls or wall portions of the member and a visual indicator responsive to time spaced echoes of the ultrasonic beam reflected respectively from the opposing walls or wall portions and received by the transducer to indicate the presence or absence of flooding in the member. The transducer is located in the bridge plate of a jig and its beam passes through an aperture in a support frame of the jig. The support frame has a pair of spaced magnetic feet attached to a bracket on the frame and a further magnetic foot secured to the frame, the feet permitting the jig to be clamped onto a steel rig member so that the transducer can be optimally aligned with the member to optimize received echoes.

Abstract: In a method of replacing a section of an old cast iron main with a new main of plastics pipe material, the section to be replaced is isolated from the adjacent live main after a by-pass is fitted between the section and the main. One end of the pipe is then pushed up the isolated section until a desired length is located within the isolated section and the other end of the pipe is connected to the end of the adjacent main. This enables the isolated section to be kept alive solely by gas flow through the pipe from the main and the by-pass can therefore be removed.

Abstract: A lubricated bearing has a rotatable structure which includes a housing with an opening at one end, a bearing cup and a retaining member. The retaining member grips the exterior of the bearing cup and the interior of the housing to secure the bearing cup within the housing with its mouth towards the opening and with lubricant spaces between the housing and bearing cup both above and below its rim. A stationary member has a spherical part which fits within the bearing cup to provide relatively rotatable bearing surfaces and a shaft which extends out of the housing through the opening.

Abstract: A fail safe controller for a fuel burner has a rectifying probe positioned in the region occupied by the flame when it is burning normally. An alternating current power supply coupled to the probe is periodically interrupted by an inhibit circuit when the flame is burning. The intermittent rectified output from the probe controls the fuel supply by way of a diode pump circuit which ensures fail safe operation as it gives a null output for a steady state input.

Abstract: Methane-containing gases are produced by passing a hydrocarbon feedstock having a boiling point of not greater than 350.degree. C. and steam over a catalyst at an elevated pressure and at a temperature of from 350.degree. C. to 550.degree. C. at the inlet of the catalyst and an exit of temperature of at least 450.degree. C., the catalyst comprising a reduced catalyst precursor which is resistant to deactivation by polymer formation or by sintering, the catalyst precursor containing (1) from 0 to not more than 0.43% K and from 0 to not more than 0.1% Na, (2) the combined weights of Na+ K does not exceed 0.011 gm atoms/100 gm of catalyst precursor, (3) the ratio of Na:K falls within the area defined by ABCDEO in FIG. 1 of the drawings, and (3) at combined Na+ K weights of from 0 to 0.05% the water loss is not more than 11.2%.

Abstract: An iron based alloy comprises between 6 and 20% by weight niobium and between 5 and 10% by weight aluminium, the balance being iron and incidental impurities. Preferably the alloy comprises between 7 and 17% by weight niobium and suitably between 5 and 6% by weight aluminium.The alloy is suitable as a component in a coal gasifier eg. as a gas inlet or outlet tube or as a structural support member because of its high resistance to corrosive attack by sulphur-bearing gas such as hydrogen sulphide.Typical alloy compositions comprise 7.6% niobium, 5.3% aluminium, balance iron and incidental impurities and 16.6% niobium, 5.0% aluminium balance iron and incidental impurities.

Abstract: A low-cost data logging device, particularly suitable for recording gas meter performance having an electrical transducer to produce an electrical analogue of a parameter to be recorded, a calculator circuit to perform an analysis of measurements of the parameter and a plurality of memories to store the results of the analyses.

Abstract: A pipeline pig 21 for removing condensed gas from the wall of a pipeline 23 comprises a cylindrical body 22 which is a sliding fit in the pipeline 23 and has an axial passage 26 extending therethrough and a flow gas ejector inlet tube 37 extending into the passage 26. The passage 26 is formed with a venturi 27 and the tube 37 is formed with a restriction 38, the forward end of the tube 37 terminating upstream of the venturi 27. The pig 21 is propelled through the pipeline 23 by differential gas pressure acting upon it and gas flows through the passage 26 so that condensed gas is entrained into the passage 26 by way of an annular duct 32 and radial ducts 35 into a rear tapering portion 29 of the passage 26 upstream of the venturi 27. The condensed gas is drawn to the forward end of the ejector tube 37 which end is located downstream of the ducts 35 and is subjected to the turbulent flow of the flow gas which has been accelerated by the venturi restriction 38 in the ejector tube 37.

Abstract: The invention is a recuperative burner, with heat exchange between the exhausting combustion products and incoming combustion air to the burner nozzle, in which the recuperator essentially comprises separable components of conical shape. The advantages are ease of dismantling, even if the conical components have distorted in use; improved flexibility of design, resulting in better efficiency and reduced formation of nitrogen oxides; and lower costs for both manufacture and maintenance.

Abstract: Heavy hydrocarbon feedstocks, e.g. gas oils, are vaporized and subsequently gasified at high temperatures without pyrolytic degradation by first admixing the hydrocarbon with a hot gaseous reactant, e.g. product gas or steam, to bring the temperature of the mixture above that of the dew point of the hydrocarbon and thereafter raising the temperature of the mixture to above that at which pyrolysis of the hydrocarbon begins to be significant by admixture with further quantities of the reactant which are superheated thereby to bring the temperature of the resultant mixture to that required for effecting a catalytic gasification reaction.

Abstract: A fail-safe supervisory circuit for a microprocessor-controlled fuel burner has a diode pump circuit (C4, C5, D7, D8) triggered by a resettable monostable (R7, T2, R8, C3) responsive to an encoded signal from the microprocessor, to act as a watch-dog timer. A triggered bistable (D1, T1, R2, IC8) provides a RESET signal on power-on or manually. A direct connection from this bistable to the monostable enables the timer circuit until the microprocessor program commences.

Abstract: A pipeline inspection system in which a vehicle, which has sensors to detect flaws in the pipeline, is moveable within the pipeline by a fluid flowing in the pipeline, and wherein a speed control for the vehicle is provided by a braking device which imposes a continuous axial drag on the pipeline wall. This continuous axial drag is adjustable between upper and lower limits such that the summation of the variable drag characteristics of the pipeline and the imposed drag remains approximately constant and the vehicle will move at a speed substantially equal to the average flow velocity of the fluid in the pipeline.

Abstract: A tool for mounting a fitting on a pipe or demounting it therefrom without the application of torque to the pipe comprises two clamping member mounted on a coupling member together with means for applying a torque to the fitting.

Abstract: A friction drive wheel, particularly for obtaining a rotary drive for a hydraulic pump or electrical dynamo on a pipeline inspection pig, has a hub with a central hole and keyway for mounting on a axle. Attached to the hub is a rim in which are mounted bundles of bristles in ferrules. The bundle axis is at an acute angle to the radius of the wheel so that the bristles will act as a leading strut. A flange stop may be provided to limit deflection of the bristles.

Abstract: A fuel burner control system is disclosed which uses a frequency sensitive diode pump circuit fed by a series of input pulses having a repetition rate within a predetermined range. The diode pump circuit produces an output having a direct current component which exceeds a predetermined threshold when the repetition rate of the input pulses is within a predetermined range. A comparator circuit delivers a pulse signal to a fuel control device when the direct current component exceeds a predetermined threshold.

Abstract: Soluble thiosulphates present in aqueous redox systems comprising at least one salt of an anthraquinone di-sulphonic acid and at least one water soluble compound of metal having at least two stable oxidation states, for example a vanadate, are converted to sulphates by introducing oleum or sulphuric acid into the lower half of a vessel containing said thiosulphate containing redox solution, wherein the sulphuric acid has a concentration of from 10-98% w/w H.sub.2 SO.sub.4 and the amount of said sulphuric acid is such that the gram molecular weight ratio of sulphuric acid to thiosulphate is from 1:2 to 1:3, and thereafter separating the sulphate formed for example by using a solubility lowering technique. The process is carried out at ambient temperature and at a temperature of from 70.degree. C. up to the boiling temperature of the acidic mixture.

Abstract: A testing circuit for a control system has a two-state input circuit connected across a plurality of switching devices. The input circuit assumes one state when any one of the contacts is closed and the other state when they are all open. An indicator device shows whether the contacts are functioning correctly.