Abstract: A method for determining the safety of a gas mixture containing first and second flammable components together with non-flammable components, comprises using an optical detector to make at least two measurements influenced by the concentration in the gas mixture of the first and second flammable components. The percentage lower explosion limit of the gas mixture is calculated by a method based on the combination of the measurements. The method leads to acceptably accurate results, despite the presence of other flammable component(s) in the gas mixture.

Abstract: A method and apparatus for determining the safety of a gas mixture containing flammable components such as methane together with ethane or other hydrocarbon, together with a diluent gas. The method includes the filtered infrared spectroscopy of the gas mixture in a gas cell using a filter. The peak transmission wavelength and bandwidth of the filter are so chosen to provide an output, when an infrared light source having a flat wavelength distribution is used, indicative of the % LEL of the gas mixture, within a predetermined tolerance. The filter may be a gas correlation filter containing a mixture of methane and ethane, together with a diluent gas.

Abstract: A meter for the measurement of the gas mass flow rate and total liquid mass flow rate of a two phase or multiphase fluid is disclosed. The meter comprises a series of three flow element, the firs element is arranged to mix fluids passing therethrough and the second and third elements are each arranged to provide a measurement of the differential pressure across that element. The second and third elements may be added to an existing installation with an element capable of performing mixing, after the mixing element. The second and third elements provide independent measurements by having different configurations presented to the fluids passing therethrough. The first and third elements may comprise conduits with internal projections and the second element may be a venturi. A flow element for use in such a meter is also disclosed.

Abstract: A method for securing a branch assembly to a “live” pipeline. An upper part of the assembly incorporating the branch is positioned on the pipeline over a containment ring located on the pipeline and within which is an annular seal surrounding an area from which the branch is to extend. A lower part of the assembly is positioned on the pipeline beneath the upper part and the two parts are secured together so that the seal is compressed and an annular space is left between the two parts and the external surface of the pipeline. Grout is injected into the annular space and cures to bond the two parts forming the branch assembly in position on the pipeline. The use of grout avoids having to use welding techniques on a “live” pipeline. A coupon can be cut out of the pipeline, via the access through the branch.

Abstract: The present invention is an improved method of installing a flowline below the surface. The method includes the steps of establishing first and second sight relief holes along a linear path, positioning a directional drilling machine on the surface, boring a first portion of a pilot hole from the surface to the first sight relief hole, determining the elevation of the boring tool and adjusting the boring tool to the desired depth, boring a second portion of the pilot hole to the second relief hole, and determining the elevation of the boring tool and adjusting the tool to the desired depth. In another aspect of the invention, a method for directionally boring a flowline is provided.

Abstract: A water detecting apparatus includes a source of infra-red radiation which is reflected off an inner surface of a pipe wall onto a mirror directing the infra-red signal along a path to an infra-red detector connected by an electrical signal path to an electronic control. The path is interrupted by a rotating chopper having windows occupied by two optical filters. The first optical filter only passes an infra-red signal of wavelength 1900 nm which is absorbed by water, while the second optical filter only passes an infra-red signal of wavelength 2200 nm, another wavelength absorbed by water, but not to the same extent as the 1900 nm wavelength. The 2200 nm wavelength serves as a reference signal.

Abstract: A method for securing a shell assembly to a pipeline. A two part shell assembly is secured to the pipeline and holds in position an annular sealing arrangement located about a predetermined area of the outer surface of the pipeline. The sealing arrangement includes a containment ring surrounding an annular seal. The containment ring is provided with connected through passages so that sealant can be introduced by a hole in the assembly into the passages to provide sealing between the containment ring and the pipeline, and between the containment ring and the shell assembly. Thus, should the annular seal fail during service the introduced sealant provides a seal.

Abstract: A suction excavator including an air pump for generating a flow of air and a nozzle through which air is drawn under the influence of the air pump, the nozzle being arranged when in use to suck up spoil from an excavation, and a mechanism for separating spoil from the air drawn through the nozzle. The excavator is provided with a fuel gas detector to detect for the presence of fuel gas in the flow of air drawn up through the nozzle. When fuel gas is detected a valve may be actuated to interrupt the flow of air up through the nozzle and instead to admit air from a substantially fuel gas free source to flush any fuel gas out of the system reducing the risk of an explosion.

Abstract: A hydraulic compressor arrangement includes hydraulic rams A and B with associated non-return valves. A hydraulic pump, typically electrically operated, provides a pressurized fluid source to operate rams A or B to allow the associated chambers to receive and compress the low pressure gas provided by a valve. The rams A and B alternately compress and allow entry of the gas so as to produce a continuing source of compressed gas by a pipe to a gas storage tank by a quick release coupling. Two stage compression can also be utilized.

Abstract: A pipe leakage detection system which includes a flexible probe with a body portion of sufficient length to pass along a pipe. Pairs of seals define a seal volume with the inner pipe wall. An adjacent test region can be used to determine leakage. A source of fluid pressure is applied to lines. With equal pressure in both seal and test regions as indicated by a manometer no leak will occur around the seals. A deliberate outgoing flow rate is allowed from a line and any differential in flow, as detected by flow meters, will indicate an actual leakage rate.

Abstract: An energy meter which measures a volume of gas supplied, which measures a calorific value of the gas supplied, and which calculates an energy value corresponding to the measured volume of gas supplied and the calorific value. The structure to measure the volume of the gas supplied and to calculate the energy value may be provided in a single unit. The structure to measure the calorific value of the gas supplied preferably includes a structure to measure the speed of sound in the gas and further preferably measures a first thermal conductivity of the gas at a first temperature and measures a second thermal conductivity of the gas at a second temperature which differs from the first temperature, and is arranged to produce the calorific value of the gas corresponding to the measured speed of sound in the first and second thermal conductivities.

Abstract: A method and apparatus for measuring the relative density of a gas, for example natural gas. The gas is supplied through an inlet to a chamber and is output through an outlet. Using a control and an ultra-sonic transducer emitter and an ultra-sonic transducer receiver, the speed of sound in the gas corrected to standard conditions is calculated. Then, the control operates to measure the relative density RD of the gas using the formula RD=a×SoSsc+b, where SoSsc is the speed of sound in the gas corrected to standard conditions, and a and b are constants.

Abstract: A pipeline inspection vehicle which can be towed through a pipeline via a cable. The vehicle includes a power unit, a master processor module, and a coil which generates an eddy current field which passes along the pipe. The resultant field is detected by a master sensor ring and slave sensor ring. Information on an amplitude and phase of the detected field together with vehicle orientation information is sent to a base station which has a computer. A distance encoder also is provided to assist in locating the position of any detected faults.

Abstract: A method and apparatus for measuring the calorific value of a gas. The apparatus includes a chamber to which a gas in question, for example natural gas, is supplied through an inlet and leaves through an outlet. The speed of sound SoS at ambient temperature is measured using any suitable method such as electronic control and a calculating device and an ultra-sound emitter and an ultra-sound receiver. The ambient temperatures Ta, is observed by a temperature sensor, and a thermal conductivity sensor measures the thermal conductivity of the gas at two different temperatures above the ambient temperature. One value ThCH, of the thermal conductivity is measured at 70° C. above ambient and the other value ThCL of the thermal conductivity is measured at 50° C. above ambient. The control calculates the calorific value CV of the gas according to the formula: CV=a·ThCH+b·ThCL+C·SoS+d·Ta+e·Ta2 +f, where a, b, c, d, e and f are constants.

Abstract: An apparatus which guides a cable through a conduit. The apparatus includes a guide device for receiving the cable. Passage of the cable through the guide device is permitted. Further, the guide device is automatically moved from a first position to a second position during passage of the cable into the conduit to assist in the movement of the cable along the conduit.

Abstract: A pipe leak testing arrangement which includes a device having sealing bags joined by a coupling. When inflated, the bags form a seal volume chamber. The bags may not form a perfect seal, and as a result leakage past the bags may occur when a differential pressure is present. A remaining portion of the pipe forms a test volume chamber. A first transducer measures differential pressure between the chambers and a further transducer measures the test chamber pressure. Measured pressure information is used by a control device to track pressure change and to adjust the seal pressure so as to maintain equal pressures even if the test pressure decays due to a pipe fracture. In an alternative arrangement, two separate devices with associated circuitry are provided to facilitate two temporary seal pressure chambers with the test chamber therebetween.