Abstract: The invention is a method and device for permanent seismic monitoring of an underground formation by means of one or more seismic emission-reception sets comprising a source (S) such as a vibrator and elastic wave receivers (R1, R2, . . . , Rn) such as geophones and/or hydrophones. A well (W) is drilled into the ground. Seismic receivers (R1 to Rn) are lowered therein and coupled with the surrounding formation. The section of the well is widened in the upper part thereof so as to form a cavity (P) against whose walls the seismic source (S) is pressed. Receivers (R) and source (S) are connected to an outside signal control and acquisition station (ST). The wells (W) can be exploration wells that are drilled for example around wells intended for production of reservoirs containing fluids, or mixed exploration and production wells. Each source can also be coupled with a cavity next to the well.

Abstract: Natural gas whose calorific value is to be determined is illuminated with a light beam that is applied by a measurement head and that defines three measurement bands with different wavelength ranges each having a bandwidth of 10 nm to 20 nm and all situated in the near infrared. The intensity of each light beam is measured after it has passed through the gas, and the calorific value of the natural gas is computed in situ and in real time on the basis of the optical absorption values obtained by measuring the intensities of the light beam after it has passed through the gas.

Abstract: The flow conditioner for a gas transport pipe comprises at least one perforated plate disposed essentially perpendicularly to the axis XX' of the pipe and comprising a central hole and sets of additional holes that are regularly distributed over at least three concentric rings centered on the axis of the pipe so as to define a perforated plate that is axially symmetrical. Within any one ring all of the circular holes are of the same diameter d.sub.1, d.sub.2, d.sub.3. On going away from the central hole and on passing from any one ring to an adjacent concentric ring, the diameter of the holes changes alternately in a reduction direction and in an increase direction. Each ring has a number of holes that is equal to or greater than six. The perforated plate is advantageously associated with a porous plate situated upstream from the perforated plate and parallel thereto.

Abstract: The invention relates to a method and apparatus for installing a branch connector on a buried pipe for transporting a fluid, and to do so by means of a multi-purpose long handle from the top of an excavation. The apparatus comprises a bottom saddle positioner having a support structure on which there are disposed firstly clamping connection means adapted to the diameter of the pipe together with a support adaptor for supporting a bottom saddle, and secondly means for releasably fixing the positioner to the end of the multi-purpose long handle and situated on the side of the support structure opposite from its side on which the clamping connection means are situated.

Abstract: An absorption refrigeration system which utilizes absorption with a double separating effect where the pressure of the condenser (K2) is offset relative to the pressure of the second generator (G2). In this system, absorption of the working mixture is achieved using methanol as the refrigerating agent and a compound having a methylphenol group as a solvent. The system is useful for producing cold or heat, particularly for the air conditioning of elementary units of a building.

Abstract: A gas burner for a cooking apparatus including a head and a cap to be laid upon the head is disclosed. The head includes a base formed with a through-aperture for feeding an air/gas mixture and a peripheral skirt formed with slits substantially perpendicular to the plane of the base. The burner has a plurality of protrusions on the top face of the skirt, each one of the protrusions being at equal distance between two adjacent slits and located at least in part in the inner half of the top face of the skirt.

Abstract: The method concerned is for connecting a section of buried main conduit (120) to a secondary conduit. For this purpose, a starting pit (200) and a finishing pit (204) are dug, a drilling device comprising a series of rods to be placed end to end is lowered into one pit in a manner such as to drill along a horizontal axis at the level of or at a height close to that of the main conduit. Upon completion of the drilling, the secondary conduit is passed through the bore-hole (202) in a manner such that an end portion is situated above the pit, this portion is fixed to a first region of a branch connector for connecting the two conduits and this end portion, equipped with its connecter, is lowered into the pit and the connector is fixed to the main conduit.

Abstract: The universal mixer device for mixing two gaseous fluids comprises an enclosure defining coaxial chambers, ducts opening out respectively into each of the chambers to feed them with two gases at medium pressure, and sonic nozzles each comprising a hollow converging-diverging body of revolution serving as seats for respective cone-shaped valve members. The valve member of one of the nozzles has an axial bore and defines the chambers at least in part. The other nozzle is disposed inside the axial bore. The hollow converging-diverging bodies of revolution occupy positions that are determined relative to the enclosure, and the valve members are mechanically linked to each other and are associated with a single actuator. The gases that have passed through the coaxial and geometrically similar nozzles flow into a common downstream chamber in which the gases mix with a predetermined mixing ratio determined by the dimensions of the nozzles.

Abstract: The invention concerns a catalyst, in particular for reducing NO.sub.x, using methane or any mixture containing mostly methane. The catalyst consists of a zeolite of mordenite structure with "small pores" exchanged with Pd and/or Co. The invention is useful for reducing nitrogen oxides.

Abstract: A drilled hole (1) is produced by means of a drilling rod assembly comprig a succession of rod elements (7d) to be arranged end to end. For this purpose, a vertical shaft (2) is produced in the ground, of constant horizontal section and preferably insufficient for a man to be able to work towards the bottom of it, the rod assembly is displaced therein from an opening located in a front wall of the shaft, and the elements (7) of the rod assembly are selected so that they have an axial length less than the distance separating the said opening in the front wall of the shaft from the opposite rear wall.

Abstract: The invention is a method for facilitating discrimination and identification of seismic or microseismic events by means of permanent pickups in an underground zone under development. The method comprises permanent installation of, in one or more wells, elastic wave receivers, geophones and hydrophones leaving the wells clear for development of the zone, at least one reference pickup with direct acoustic coupling with the technical zone development equipment (pickup pressed against a production string for example) for detection of events directly connected with the operation of the wells (valve opening and closure, etc.

Abstract: It concerns butt-welding of parts made of plastics material(s). For this purpose, the invention proposes correcting, according to an ambient temperature which is measured in the environment of the parts at the moment of welding, at least one of the following parameters: pressure(s) for contact and/or welding of the parts, electrical energy to be supplied to means for displacement of the said parts, stroke(s) of relative displacement of the parts, time for obtaining beads at the end of the parts during the phase of heating the latter.

Abstract: A process for hollowing out a cavity, by dissolution, in a ground formation comprising at least one layer containing predominantly salt, the process including the steps of drilling at least one hole having a substantially horizontal section arranged at least in part in the salt layer, providing in the drilled hole(s) an injection pipe, an extraction pipe and a preliminary communication space connecting the injection pipe and the extraction pipe, injecting a solvent of the salt, into the communication space, through one end of the injection pipe forming an injection point, extracting, through the extraction pipe, the brine formed by the dissolution of the salt, in contact with the solvent, producing a plurality of preliminary sub-cavities in the salt layer, and producing a succession of channels, isolated from the layer, the succession of channels connecting the plurality of preliminary sub-cavities in a fluid manner two at a time in order to form an open circuit for circulation of the solvent, expending betwe

Abstract: The invention relates to a gas mixing burner (80) equipped with a flame retention device (1). This device incorporates in its construction a compressed gauze of interwoven flexible metal wire or wires for said gases to flow through it, and takes the form of a ring (2), characterised in that it is constituted by a substantially coaxial stack of at least two of said rings (2). Such a device may in particular be mounted on cylindrical domestic burners.

Abstract: A continuous pyrolysis and decoking process and apparatus is described for the production of acetylenic compounds, in which hydrocarbons and steam are circulated in at least one tube (31) of a steam cracking reactor (30) and steam is circulated in at least one tube (32) of that reactor. The hydrocarbon effluent and steam then circulate in at least one row (1) of a pyrolysis reactor (40) and the decoking effluent comprising steam circulate in at least one other row (2) of that reactor (4) to effect decoking. A set of valves V1, V2, V11, V12 is used to alternate the pyrolysis step path and the decoking step path. The temperature in the steam cracking furnaces is lower than that in the pyrolysis reactor.

Abstract: A gas-fired direct-contact water heater system 10 is described. It consists of a first housing 11, 50, 80 having a packing 16, 51, 81 of heat exchange elements 17 and on which water is sprayed. A burner 18, 52, 83 is disposed on the side of the housing under the packing. A combustible gas feed pipe is connected to the burner 18, 52, 83 to provide a combustible gas to the burner. A water collection reservoir 20, 58, 86 is defined below the burner for collecting heated water. A further packing 31-59-91 having heat exchange elements is located in a further housing 30-60-90 and it is also sprayed water. Ambient air is admitted under this packing by a blower 32-63-101 whereby the air is humidified and heated and supplied to the burner for admixture with the gas whereby to obtain a higher combustion product dew point and a reduction in the NO.sub.x emission when burned.

Abstract: An oven, including an inner compartment comprising side walls, a lower wall, an upper wall and a back, an outer compartment defining a casing and surrounding the inner compartment in order to delimit therewith a continuous intermediate space, a heat generating device for producing heat by conduction, convection or radiation connected to the casing and mounted between the inner compartment and the outer compartment, a source of energy, with the exception of sources of microwaves, connected to the heat generating device and intended to generate the heat, and at least one heating zone, opposite which is situated the heat generating device, the heat generating device is mounted so as to be movable relative to the casing and to the heating zone, wherein the two compartments are substantially concentric and the heat generating device is mounted so that the heat generating device rotates between the inner compartment and the outer compartment.

Abstract: The invention concerns a process for excavating by dissolution an underground cavity in a thin salt layer, in order to store a fluid therein. According to the invention, the process includes the steps of producing an injection duct, an extraction duct, and a void for a communication space which places in communication the injection and extraction ducts, producing at least one blind tunnel void communicating with the communication space so as to enable the solvent to circulate and the salt to dissolve in the blind tunnel, injecting via the injection duct a solvent into the communication space, and extracting via the extraction duct the brine formed by the dissolution of the salt on contact with the solvent. The advantage of this process is that the excavated layer has a mechanically stable shape and a larger volume and is produced more cheaply than with prior processes.

Abstract: A refrigerating mixture is compressed in the penultimate stage of a plurality of stages of a compression unit. The mixture is partially condensed in order to cool it substantially to ambient temperature; the condensed mixture is separated in order to obtain a vapour fraction and a liquid fraction; the vapour fraction is cooled and partially condensed; the resultant vapour fraction is sent to the final compression stage at least the high pressure vapour fraction and the liquid fraction are cooled, expanded, and circulated in at least first heat exchange means (5) with the fluid to be cooled.Moreover, according to the invention, during condensation of the vapour fraction, the vapour fraction produced by separating the condensed mixture is cooled by circulating it in heat-exchange relationship with a refrigerating fluid, in second heat exchange means.

Abstract: A chiller for cooling a chilling fluid that feeds an air-conditioning system of a building, the chiller comprising firstly a boiler-separator for separating the two components of a refrigerant, one of which components is volatile, by heating and evaporation, and secondly a mixer for reforming the refrigerant by evaporation and absorption.