Abstract: A seal is fed into an existing pipe. Manipulation of an elongate assembly deploys the seal and engages the seal body with the end of the pipe. A plastic pipe is advanced into the pipe, and the space between the existing pipe and the plastic pipe is filled with sealant. The elongate assembly is withdrawn.

Abstract: Method of lining a pipe. An outer pipe of ferrous metal is lined with a lining pipe of crosslinked polyethylene which is initially provided as a precursor lining pipe. The precursor lining pipe is initially made of cross-linked polyethylene with an external diameter equal to the internal diameter of the outer pipe. The initial pipe is then drawn through a die to form a pipe with a smaller diameter. The material of the pipe is memory material so that when it is melted it automatically expands to the original size. The precursor pipe is inserted into the outer pipe and melted by drawing a burner through it. The burner burns fuel gas supplied with combustion air through a hose by which the burner is towed. Hot products of combustion melt the polyethylene causing the precursor lining to expand automatically into the lining pipe. This is supported by gas pressure of a desired value inside the lining pipe until the polyethylene solidifies on cooling.

Abstract: An energy meter for measuring parameters of fuel gas. The meter has a gas inlet and outlet and a central tube along which the gas flows from inlet to outlet. Ultra-sound transducers and a control form a system whereby the speed of ultra-sound signals traveling through the gas between the transducers is measured and used in the control to calculate the volume of gas which is passed through the meter. The ultra-sound signals pass through apertures in the walls of chambers containing the transducers. Another ultra-sound transducer in the chamber which is connected to the control acts as an emitter and receiver of ultra-sound signals reflected by reflectors. These signals travel through the fuel gas in the chamber and their attenuation is observed and measured by the control when they are received by the transducer. The measured attenuation is used to derive the calorific value and/or Wobbe index of the gas.

Abstract: A liquid delivery nozzle having a circular dispersion plate having an upwardly facing concave side spaced from an output end or orifice of a tube connected to a water supply which may deliver water to the output end at a pressure in the range of 0.3 to 0.5 bars. The water issuing from the output end impacts on the concave side and spreads thereover to fly off the periphery of the plate in the form of drops having little or no vertical velocity component. The major part of the water issuing from the tube is converted into large drops of at least 0.7 mm in diameter. The nozzle can be used in an installation to prevent, suppress or impede the occurrence or development of explosions.

Abstract: An in-pipe vehicle for carrying out at least one operation in a pipeline. The vehicle includes a train of modules interlinked by suspension units to allow serpentine movement through pipe bends. The vehicle train has its own internal power supply and drive mechanism in the modules. A detector module determines the presence of a service junction using magnetic field information. A manipulative module allows the vehicle to be temporarily wedged in the pipeline while providing rotational movement to facilitate the desired operation at the junction. This may include drilling and welding of a service pipe to the main using appropriate modules. A remote probe typically containing a magnetic field generator can be used to assist in service junction location by the vehicle.

Abstract: A thermosyphon radiator comprising a sealed panel is formed into two or more discrete chambers, each containing a reservoir of vaporising liquid in a lowermost part of the panel and a heating member extending with clearance through the lowermost part of the panel, the member being at least partially immersed in the vaporising liquid.

Abstract: Diver communication equipment comprises a diver's helmet having a display consisting of a monitor, a prism, a relay lens and an eyepiece. The relay lens and the eyepiece are mounted in a tube which extends into the helmet through a sealing bush located in place by a nut. The helmet also caries a television camera and a light. By looking up at the eyepiece, the diver can see, through one eye, video images from the monitor derived from the camera or from another camera located topside of some other graphical or numeric information derived either from other devices subsea or other sources located topside. In a modification, the monitor occupies the tube.

Abstract: A cooking oven comprises convection and microwave heat sources (not shown), controls 1 and 3,4 for presetting the temperature and cook time of the oven for a food item to he cooked therein, a further control 5 for selecting a reduced time cooking routine for the oven, and a microprocessor (not shown) responsive to the operation of the further control 5 for controlling the convection heat source and/or the microwave heat source in accordance with a reduced time cooking routine which is determined by the preset temperature and cook time (FIG. 1).

Abstract: Apparatus provides an air/fuel mixture to a fully premixed burner and comprises means for providing fuel at a variable flow rate to the burner, means for supplying air at a variable flow rate to the fuel to form the mixture, means for sensing aeration of the fuel combustion products and control means for controlling the fuel flow rate in dependence upon a heat output demand and the air flow rate in dependence upon both the fuel flow rate and the sensed aeration in such a way that the air flow rate is sufficient to maintain the aeration at a predetermined value, the controller, in use, maintaining the fuel flow rate at one of a number of predetermined values and the air flow rate at a corresponding one of a number of differing predetermined values, each set of predetermined values being characterized by a constant value of the ratio between successive values.

Abstract: Steel pipe items such as pipes (10) are each joined by a girth weld (14) to tubular steel fittings (12) and the pipes (10) are each lined by pulling a polyethylene liner (30) through the pipe (10) and through the fitting (12). A ring (32) is forced into each fitting (12) to compress the liner (30) and force it into grooves (20) in the internal surface of the fitting (12). The grooves (20) are separated by castellations (22). The grooves (20) are in a corrosion-resistant cladding (18) deposited on the interior of each fitting (12). Alternatively, the whole of each fitting (12) is made of corrosion-resistant Duplex steel. The ends of the liners (30) are cut short of the ends of the fittings (12) and an annulus 940) of liner material is inserted in the gap. The annulus (40) has an external groove (42) accommodating a body (44) of heat insulation material. The ends of the fitting (12) are joined by a girth weld (15).

Abstract: An adsorbent for separating nitrogen from a feed gas containing at least one other gas having molecular dimensions equal to or larger than methane, the adsorbent comprising clinoptilolite having a sodium ion content of at least 17 equivalent percent of the total ion exchangeable cations and optionally one or more non-univalent cations, which if present comprise in total less than 12 equivalent percent of the total ion exchangeable cations, the balance, if any, being one or more non-sodium univalent cations.

Abstract: Apparatus provides an air/fuel mixture to a fully premixed burner (4) and comprises a fuel line for providing fuel to the burner (4) a fan for supplying air at a variable flow rate to the fuel to form the mixture, a sensor (30) for sensing aeration of the fuel combustion products and a controller (26) for controlling the air flow rate in dependence upon the aeration sensed in such a way that the air flow rate is sufficient to maintain the aeration at or close to a predetermined value, the controller, in use, maintaining the air flow rate at one of a number of differing predetermined values which are in the form of a geometric series characterized by a constant value of the ratio between successive values.

Abstract: A self-centering suspension for use in supporting a vehicle or vehicles intended to travel in a pipeline includes a body and two sets of three wheels spaced apart along the length of the body. Each wheel is mounted on a lever arm biased by torsion springs against the inner surface of the pipeline. Each lever arm has a stub arm which is eccentrically arranged relatively to a rotary joint in the form of a pin, and the stub arm slidingly engages a circumferential groove in a ring. Each ring slides on the body. A set of three wheels are thus constrained to move inwards and outwards together.

Abstract: A method for permitting the joining together of two adjacent pipe lengths with adjacent ends curving with substantially the same sense, the method comprising rotating the end of one of the pipe lengths about its axis until it curves in substantially the opposite sense to the curve of the adjacent end of the other pipe length.

Abstract: A corrugated plastic service pipe 20 is inserted together with a flexible guide assembly 22 through an accessible end 11 of a steel service pipe 14, 10, which extends from the end 11 to a main 18. The flexible guide assembly 22 comprises a flexible guide element 24 and a flexible spring guide 26. The element 24 extends through a nose-piece 32 having an outer part secured to the pipe 20 and an inner part 36. The spring guide 26 carries a sensor 60 at its tip which emits a signal when the sensor enters the main 18. When the pipe 20 is correctly positioned fluid sealant 70 is injected into the space between the pipe 20 and the pipe 14, 10. When the sealant has solidified sufficiently, the guide assembly 22 is withdrawn through the pipe 20, the inner part 36 being separated from the outer part 34 to allow withdrawal of the spring guide 26.

Abstract: Apparatus for cutting a hole through a plastic liner in a gas or other main comprises a body forming module of a train of modules adapted to travel through the main. The body has a radially movable platform carrying a cutter. The platform has four cams engaging four cams pivotally mounted on tie-bars. Advancing movement of the platform pushes the cams outwardly causing support legs to move outwardly and to cause four slave legs carried by the support legs to engage the plastic liner. Further advancing movement of the platform causes the cutter to engage the liner and also holds the support legs in their advanced position as noses on the cams traverse the faces of the cams.

Abstract: An excavated opening (10) through a pavement (12) of a highway and through the underlying base material (14) to expose a gas main (16) is filled by (i) mixing on site cement, foaming agent and water to produce a fluid grout (26), (ii) mixing the grout with loose excavated spoil (22) in the opening, (iii) agitating the mixture using a hand-held poker vibrator (30), (iv) and repeating this procedure until the level (40) is reached. The level (40) corresponds to the underside of a protective layer (50) which is subsequently applied. The majority of the excavated loose spoil from the opening is reused.

Abstract: A combined heat and power system including a 4 cylinder reciprocating internal combustion engine fuelled by a fuel gas, for example natural gas, and operating at a substantially constant speed and at a substantially constant air to fuel ratio. Operation of a spark generator and distributor device (44) is under control of an ignition spark duration control (10) whereby the duration of an ignition spark between the electrodes of the plug (16) is automatically variable to bring the spark duration closer to a predetermined minimum duration over which predetermined minimum duration there would be supplied to the electrodes of the plugs in turn a minimum-level of electrical ignition energy to substantially avoid misfire in the cylinders provided with the plugs. The minimum level of the electrical ignition energy is variable according to the size of the gap between the electrodes of the plug (16).

Abstract: A pipe of polyethylene is reinforced by two layers of polyethylene tape wound around the pipe in opposite directions under tension. The pipe contains carbon black and the layers are unpigmented and free from fillers and are transparent to infra-red radiation to which the first major surface is exposed. The radiation is in the near infra-red region and has a substantial part of the radiant energy of a wavelength of less than 2.5 micrometers. Very little radiation is absorbed by the layers but a very high absorption occurs in the outer surface of the pipe. This causes the interface between the second major surface of the layer and the first major surface of the pipe and between the second major surface of the layer and the first major surface of the layer to reach temperatures at which fusion welding in the layers welds them together and welds the layer and the pipe together.