Abstract: Each module includes a tubular member filled with filling material, such as concrete, and a tube located in the filling material and extending longitudinally of the tubular member. Tubes or holes extend transversely through the tubular member and the filling material. The longitudinal tube facilitates connection of the module in end-to-end relationship with the modules using connecting mechanisms. The transverse tubes or holes facilitate securing the module to one or more like modules in side-by-side relationship using securing mechanisms. The modules may be assembled together so as to form, for example, a pipeline stabilizing and protection mat to ballast and protect underwater pipelines.

Abstract: A pipe repair clamp especially for subsea offshore work has two half-shells held together around the pipe by two sets of diametrically opposite interlocking formations comprising in each set a series of abutments integral with a half-shell and a series of hooks integral with the other half-shell. The abutments are arranged in a castellated formation and provide first surfaces opposed to and engaged by second surfaces provided by the hooks. The half-shells have opposed abutting longitudinal faces with a longitudinal seal between each two abutting longitudinal faces extending along the half-shells. The longitudinal seals at their ends seal against 180.degree. seals at each end of the clamp, each 180.degree. seal being at an end of a respective half-shell. An annular gap 18 between the clamp 10 and the pipe is fillable with repair grout.

Abstract: A fuel fired burner 1 is for use in a solid fuel effect fire such as a coal effect fire 40. The burner 1 has ports 3 for supporting a decorative effect flame. Each port 3 is connected to an electrically driven arrangement 2. When the burner is in use the arrangement 2 operates so as to vary automatically and continually the aeration of the fuel/air mixture which exits from the burner ports 3. The resulting flames supported by the burner ports are thus of continually changing visual appearance and provide a realistic decorative live flame effect.

Abstract: A temporary cover for excavations comprising a platform having a lowermost surface for contact with the ground surrounding the excavation and an uppermost surface and means attached to the platform for securing the platform to a below ground anchor point.

Abstract: An internal combustion engine has an engine unit with an exhaust pipe comprising an oxygen sensor an electrical resistance heater in a bridge circuit having a control resistance and two fixed resistances RA and RB. For calibration the cell is initially operated in atmospheric air with an heater power control circuit supplying variable D.C. power output, under control of a microcontroller, to the bridge to vary the temperature of the sensor. When the sensor gives an electrical output of a predetermined reference value, this is observed by the microcontroller which varies the value of the control resistance to a calibrating value RC2 at which the bridge nulls. Then the microcontroller is instructed to adopt the operating mode and in accordance with its program the microcontroller sets the resistance value of the control resistance at the control value RC1 correlated by an operating function in the program with the calibrating value RC2.

Abstract: An outlet opening (14) to a branch line 40 in a pipeline 10 is sealed without interrupting the flow of gas in the pipeline 10 by cutting an access opening 60 in the wall 62 of the pipeline 10 opposite the branch line 40. A seal 100 is inserted through the access opening 60 using a sub-assembly 70, which consists of a flange 74 having a screw-threaded through aperture, an externally screw-threaded tube 82 received in the aperture and a rod 80 carrying a handle 72 at one end and the seal 100 at the other. The seal 100 has a sealing face 102 which is part-cylindrical in shape and is held in the correct orientation by the handle 72 while the tube 82 is screwed home. When work on the branch line 40 has been completed a temporary seal 160 is installed in the joint-flange 16 which is welded to the pipeline 10 allowing removal of the isolation valve 64 which is replaced by a blanking flange fitted to the joint-flange 16.

Abstract: A method is provided for replacing an existing service pipe carrying fluid to an outlet within a property with a replacement service pipe. In the method the outlet is disconnected within the property from the existing service pipe in such a way that both during and after disconnection fluid is prevented from escaping into the property. A desired length of replacement service pipe is then fed into the existing service pipe in such a way that during and after the feeding step fluid is prevented from escaping into the property. The outlet is then connected to the outlet end of the replacement pipe in such a way that during the connection fluid is prevented from escaping into the property and after the connection step fluid is allowed to pass to the outlet solely by way of the replacement pipe.

Abstract: A sensor for use in installing a plastic service pipe inside a steel service pipe connected to a main includes a flexible element which is fed through the steel pipe and through the plastic pipe. The element has at its remote end two light-emitting diodes and two photoconductive cells. The flexible element and the pipe are fed together into the steel pipe. The sensor indicates when the cells have entered the main because the intensity of the light reflected to the cells falls to a low value and gives an audible or visual signal. This also indicates that the end of the plastic pipe which carries a seal is positioned correctly and that sealant can be injected into the space between the steel pipe and the plastic pipe. After the sealant has set the sensor can be recovered by withdrawal through the noise-piece and through the pipe.

Abstract: A fluid pressure reduction system includes at least two streams. A working stream includes valves with associated pressure sensors for modulating output pressure. A control system monitors pressure via a sensor and actuates a slam shut valve in the event of a fault. In the event that another stream is at fault the arrangement allows the slam shut valve to be opened. In the faulty stream only, pressure again rises, the slam shut is again shut and cannot be reopened until manually reset following fault clearance. Independent control in each stream assists in system integrity. All streams can close and reopen once. The second closure determines the faulty stream.

Abstract: Sensor apparatus 18 for use in a plastic service pipe 16 inside a steel service pipe 10 connected to a main consists of a flexible element 42 which is fed through the steel pipe 10 and through the plastic pipe 16. The element 42 has at its remote end two light-emitting diodes 80 and two photoconductive cells 82 The flexible element 42 and the pipe 16 are fed together into the steel pipe 10. The sensor apparatus 18 indicates when the cells 82 have entered the main 14 because the intensity of the light reflected to the cells 82 falls to a low value and gives an audible or visual signal. This also indicates that the end of the plastic pipe 16 which carries a seal 38 is positioned correctly and that sealant 30 can be injected into the space between the steel pipe 10 and the plastic pipe 16 and is detected by a second light sensor arrangement 154/156. After the sealant 30 has been injected the sensor apparatus 18 can be recovered by withdrawal through the nose-piece 32 and through the pipe 10.

Abstract: A kit is provided for temporarily blocking the bore of a pipe through which a fluid flows, the kit comprising an expansible flexible bag seal which is inserted through a hole provided in the wall of the pipe and an apparatus for injecting into the bag seal a quantity of a material adapted to expand in situ in the bag seal and inflate the bag seal to seal against the inside of the pipe. The pipe may be a gas main and the material may be an expandable synthetic resin foam. The bag seal is removed by injecting thereinto a substance capable of dissolving the foam so that the bag seal can be at least partially deflated.

Abstract: The invention provides a joint 80 for two steel pipes 50, 52 each containing a liner 54, 56 of polyethylene. The invention also provides an electrofusion fitting for joining the liners 54, 56; a method of making the fitting and a method of making the joint 80. The joint 80 consists of an electrofusion fitting having two frusto-conical outer end surfaces which match similar surfaces on the insides of the end portions of the liners 54, 56. Fusion welded joints are formed at the interfaces between the frusto-conical surfaces. A body of insulating material 66 is received in a central recess in the fitting and protects the fitting from the high temperature of the seam 70 between the steel pipes 50, 52. The frusto-conical surfaces make an angle of 10.degree. or less with the longitudinal axis of the fitting. A support body 14 of metal or of synthetic plastics material contained by the electrofusion fitting ensures that the fitting is adequately supported during electrofusion.

Abstract: A fuel fired burner is provided for receiving a premixture of fuel and air. A ceramic flame support extends across the burner chamber and has a plurality of elongate slots through which the fuel and air flows. Each slot has a narrow constant dimension portion that opens into a wider constant dimension portion. The outlet end of the latter portion opens into a short diverging outlet. The arrangement is such that when the burner is operating within a given heat output range, the burner flame can move between the upstream and downstream ends of the diverging outlet to seek stabilization as the heat output changes within that range, without retracting into the slot upstream of the outlet.

Abstract: A fluid pressure reduction system includes two streams, each stream having pressure regulators 19 & 20, 32 & 33. Isolation slam shuts 16 and 30 are provided in respective streams. A sequence tester 40 allows a sequence of test operations to be effected such that the slam shuts can be opened and closed and the working pressure settings to the regulators can be changed to check system integrity. These tests can be effected without interrupting the supply of gas through the system. It is also possible to carry out the sequence from another location.

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: A fluid flowmeter includes a conduit through which fluid flows by way of an inlet and an outlet for flow rate measurement. A first transducer transmits signals to and receives signals from a second transducer by way of the conduit. A second transducer is spaced from the first transducer along the conduit and transmits signals to and receives signals from the first transducer. A detector detects the time of flight of the signals between the transducers in order to measure the flow rate of the fluid along the conduct. A rod extends along the conduit to provide an annular flow path along which the signals are transmitted.