Abstract: The present invention relates to a method and apparatus for detection of hydrogen sulfide in downhole operations. A downhole tool is provided with a coupon adapted to react at varying degrees to exposure to concentrations of hydrogen sulfide. The downhole tool is positioned in the wellbore with the coupon(s) exposed to downhole fluids. A reaction to a change in the coupon, such as coloration, is used to determine the presence and concentration of hydrogen sulfide.

Abstract: Improved control of continuous processes that handle liquids. Data generated by this invention is used to control gas contents of liquids within optimum ranges, for instance in paper coating processes and in the manufacture of food products (ketchup), personal care products (shampoo), paints, and in any industry where information on entrained and/or dissolved gases, and related parameters such as true density of and gas solubility in process liquids, is employed to optimize processing. The amount of gas in a liquid is determined by subjecting a mixture of an incompressible liquid sample and a compressible gas to three or more different equilibrium pressure states, measuring the temperature and volume of the mixture at each of the pressure states, determining the changes in volume of the mixture between at least two different pairs of pressure states, and calculating the amount of gas in the liquid sample.

Abstract: A gas analyzing apparatus including a reactor for decomposing a target substance contained in a gas to produce a product gas containing a decomposition product, a contacting chamber connected to the reactor and having a quartz oscillator disposed therewithin. The quartz oscillator has opposing surfaces each provided with an electrode, at least one of the electrodes being reactable with the decomposition product so that the decomposition product when contacted with the reactable electrode is reacted with the reactable electrode to cause a frequency deviation which is detected by a frequency measuring device.

Abstract: A method for determining a correction factor for use in analysing the concentration of a gas in a liquid is described. The correction factor is determined by measuring the output concentration of the gas in the liquid as the gases saturation limit in that liquid. The method is useful with gas permeable membrane technology to measure the concentration of the gas in the liquid. The method includes applying a correction factor to give the true concentration of gas in the liquid taking into account both that gas in solution in the liquid and that amount of gas present as entrained bubbles in the liquid.

Abstract: The present invention discloses an electronically controllable brake actuating system for automotive vehicles, including an unpressurized pressure fluid supply reservoir, a pressure source actuatable by an electronic control unit, the pressure of which can be applied to wheel brakes of the vehicle, further including a device for detecting the driver's wish for deceleration as well as valve assemblies inserted upstream of the wheel brakes and connecting the wheel brakes alternatively to the pressure source or the pressure fluid supply reservoir. In order to increase the operational or functional reliability of a system of this type, the present invention discloses the provision of means for detecting gases or air disposed in the system.

Abstract: An electronic system for selectively detecting and identifying a plurality of chemical species, which comprises an array of nanostructure sensing devices, is disclosed. Within the array, there are at least two different selectivities for sensing among the nanostructure sensing devices. Methods for fabricating the electronic system are also disclosed. The methods involve modifiying nanostructures within the devices to have different selectivity for sensing chemical species. Modification can involve chemical, electrochemical, and self-limiting point defect reactions. Reactants for these reactions can be supplied using a bath method or a chemical jet method. Methods for using the arrays of nanostructure sensing devices to detect and identify a plurality of chemical species are also provided.

Abstract: In one embodiment, the present method includes the steps of introducing a volume of a sample into a vapor delivery line and volatilizing at least a portion of the volume as it is carried through the vapor delivery line. At least a portion of the volatilized volume contacts a sensor element, which produces a signal that is monitored to reveal information about the sample. All components upstream of the sensor element are substantially free of sorbent materials so that the sample volume does not contact a substantially sorbent material before contacting the sensor element.

Abstract: The present invention continuously monitors the amount of oxygen dissolved in a beverage in a beverage storage tank in a beverage filler. Gas is continuously sampled via the vent holes 28 and the vent pipe 29 from the space part inside the beverage storage tank 1 of the beverage filler and is supplied to the oxygen measuring apparatus 40. The oxygen measuring apparatus 40 includes the oxygen measuring device 45 and measures the concentration of oxygen gas of the delivered gas. Based on the concentration of oxygen gas, it is monitored whether or not the amount of oxygen dissolved in the beer inside the storage tank is at or below a predetermined level. Further, the beverage is sampled from a supply channel supplying the beverage to the beverage storage tank so that the concentration of oxygen in the beverage is measured and monitored.

Abstract: A bubble detector utilizes an ultrasonic transducer to sample bubbles as they pass the transducer. The envelope of the return signal is analyzed to determine the volume of each sampled bubble. If the total volume of bubbles sampled within a certain period of time exceeds a desired maximum volume, the bubble detector may initiate a system shut down. A bubble detector can be evaluated or calibrated by introducing bubbles into a conduit, detecting the bubbles introduced into the conduit using visual inspection or a bubble detector of known resolution and comparing the results with the examination of a bubble detector under evaluation.

Abstract: An apparatus and method of determining the gas generation potential of a liquid capable of producing gases. The apparatus may be characterized as a cylinder having first and second openings, capable of holding a volume of liquid capable of generating gas; plugging means attached to the second opening of the cylinder for sealing the second opening; a multi-port connector having at least first, second, third and fourth ports, wherein the first port is attached to the first opening of the cylinder; pressure reading means attached to the second port of the connector; valve means attached to the third port of the connector, the valve means suitable for opening and closing to allow liquid and gases to enter and exit the cylinder; and pressure relief means attached to the fourth port of the connector, wherein the fourth port is closed during the measuring operation.

Abstract: A probe (1) for quantitatively measuring volatile components of a liquid (2) includes a measurement gas space (3) separated from the liquid (4) by a permeation membrane (5). The membrane (5) is permeable for the volatile component, however nonpermeable for liquid. A selective gas detection system is arranged in the measurement gas space (3) for a defined volatile component. The gas detection system has an IR light source (6), an IR filter (7), (7′) and an IR-sensitive light sensor (8), (8′). Light falls through the IR filter on the light sensor (8), (8′). The IR filter (7), (7′) comprises a transmission window in the range of an alcohol-specific absorption band.

Abstract: The present invention provides a 12CaO.7Al2O3 compound containing an O2− ion radical and/or an O− ion radical in a high concentration of 1020 cm−3 or more. This compound can be used as an oxidization catalyst, antibacterial agent, ion conductor, or electrode material for solid-oxide fuel cells.

Abstract: An analysis device, preferably in the form of a floating buoy, is disclosed for the analysis of fluids, such as waste water. The device has a main body portion and a removable cartridge containing consumable ingredients for use in analysis.

Abstract: Improved control of continuous processes that handle liquids. Data generated by this invention is used to control gas contents of liquids within optimum ranges, for instance in paper coating processes and in the manufacture of food products (ketchup), personal care products (shampoo), paints, and in any industry where information on entrained and/or dissolved gases, and related parameters such as true density of and gas solubility in process liquids, is employed to optimize processing. The amount of gas in a liquid is determined by subjecting a mixture of an incompressible liquid sample and a compressible gas to three or more different equilibrium pressure states, measuring the temperature and volume of the mixture at each of the pressure states, determining the changes in volume of the mixture between at least two different pairs of pressure states, and calculating the amount of gas in the liquid sample.

Abstract: Method for determining a characteristic value for a binding force potential of paper fibers in a fibrous suspension. The method includes measuring an air content of the fibrous suspension and deriving the characteristic value from the measuring.

Abstract: The present invention relates to a method for the analysis of a gaseous component or of a component that can be transformed into gaseous form (23) of a sample (5) which provides that the sample (5) is filled into a sample receptacle (2) through a receptacle opening (4), and an analysis receptacle (7), which was previously supplied with a tracer reagent, is then by way of its receptacle opening (4) connected with the receptacle opening (4) of sample receptacle (2) via an adapter (10), after which step the component (23) is expelled from the sample receptacle (2) and into the analysis receptacle (7) wherein the analysis receptacle (7) is connected with the outside atmosphere in such a manner that a pressure compensation can take place. The invention further relates to a test kit, in particular, a test kit for implementing the method.

Abstract: A method for evaluating particle concentrations in the atmosphere of a clean room or of a machine mini-environment is described. The method includes exposing a test surface of a test substrate to the atmosphere for a test time, capturing an amount of particles at the test surface of the substrate at the end of the test time, analyzing the amount of captured particles, and comparing the analyzed amount of particles with a reference amount of particles from a reference substrate. An evaluation of the atmosphere of the room or environment can thus be accomplished in a relatively short time.

Abstract: A system and method for detecting bio-hazardous particulates in mail handling systems includes an air intake hood 20 that connects to a biohazard sensing suite 24 which, in turn, connects through an outlet duct 26 to a filter, adsorber, or scrubber 28 that removes any bio-hazardous material prior to exhausting the air. An air mover 30 is located in the outlet duct 26 and moves the air into the air intake hood 20 into the biohazard sensing suite 24. The biohazard sensing suite 24 detects the presence of any undesired bio-hazardous material.

Abstract: A method measures the concentration of the partial pressure of gases, particularly oxygen, in fluids. Know methods for measurements under rough conditions, e.g., measurement of the oxygen partial pressure in grounds, dumps or in the ground water are completely unsuitable. In the present method as described, in the internal area of a hollow vessel closed off to the outside, whose wall consists at least partially of a gas-specific permeable synthetic material that is in contact with the fluid with its external side, the partial pressure change proportional to the gas concentration is measured as a time-scanning of pressure change or as a change of a pressure-dependent physical variable. The measuring principle is very simple and is particularly suitable for the determination and long-time monitoring of the oxygen concentration and of further gases and can also be used in problematic locations.

Abstract: The abundance of methane, from a rock sample recovered from a subsurface formation, is determined by submerging the rock sample in a container with aqueous acid solution for release of natural gas from the rock sample and then determining the amount of released gas contained in submerged gas bubbles adhering to undisolved portions of the rock sample and the container as a measure of the amount of methane released from the rock sample. The relative abundance of methane from each of plurality of rock samples, treated with aqueous acid solution as described above, is determined by comparing the amount of gas contained in the adhering submerged gas bubbles from each rock sample with the amount of gas contained in adhering submerged gas bubbles from each of the other rock samples of the plurality of rock samples as a measure of the relative abundance of methane in each rock sample.

Abstract: This method uses a simple relationship to compute total raw coal seam (coalbed) desorbed gas volumes from geophysical logs in a well bore. Laboratory total measured raw coal seam gas desorption volumes on coal core samples are calibrated to geophysical log measurements to obtain the relationship. The relationship has different constants and exponents for coal seams in each geologic basin and depositional setting. The calibrated relationship is applied to geophysical log measurements in cored and non-cored coal seams of the same type in the same basin to obtain a continuous total gas desorption volume estimate over the entire well in order to compute natural gas reserves in place. The method can be applied to coal seams where appropriate geophysical log measurements are available in any well.

Abstract: The present invention relates to a new concept in measuring the dissolved gas levels in supersaturated liquid streams. In particular, the new device is specifically applicable to the measurement of carbonation levels in soft drinks. The measurement is made by permitting the beverage to escape from the pressurized container to atmospheric pressure through a thin tubing. The gas escaping from the supersaturated beverage separates the liquid stream into alternating gas and liquid segments. The relative long term average length of the segments is directly related to the CO2 content of the beverage. The instrument is simple to operate, inexpensive, and needs no calibration; it is easily adaptable to presently used laboratory equipment, and is useful in production process control.

Abstract: The preferred embodiment uses a chamber which is sized no larger than necessary to hold the particular type, size and shape of the baggage or cargo or containers being examined. This chamber has doors or openings sufficient to allow the easy entry and exit of objects being examined. These doors or openings are easily and quickly moved back and forth, making and breaking a vacuum seal which will withstand internal depressurization to the equivalent of an altitude of 12,000 feet above sea level. For the examination of individuals and items not in the container, a flexible tube is attached to vacuum pump. This flexible tube has a short stiff pipe on the end which is used to probe into areas to collect vapors which are then examined by the detector. The tube from the chamber feeds the air collected in the chamber to the vacuum pump which passes the collected air to the detector.

Abstract: A method and an apparatus are provided for measuring the amount of entrained gases in a liquid sample. A conduit defining a volume is provided. The conduit has an inlet at a lower end thereof and an outlet at an upper end thereof. Liquid sample is made to flow into the inlet, through the conduit, and out of the outlet. The weight of the liquid sample in the conduit is determined during a flow of liquid sample through the conduit to obtain a first measurement. Thereafter, a difference between the first measurement and a predetermined weight value representing a weight of the same liquid sample flowing through the conduit but containing no entrained gases is determined to obtain a calculated weight of entrained gases in the liquid sample flowing through the conduit.

Abstract: Volume measuring apparatus is used in a closed space as in the case of volume measurement of liquid in a container placed on an orbit of an artificial satellite and permits the volume measurement in a state without mixture with gas, liquid, or solid. A volume measuring apparatus is an apparatus for measuring the volume of liquid or solid under microgravity, which has two or more containers coupled to each other by a pipe, a device for separating or fixing a gas phase, a liquid phase, or a solid phase, a pressure fluctuation source, a pressure signal receiver, a pressure gage, and a thermometer, wherein the separating or fixing device, the pressure fluctuation source, the pressure signal receiver, the pressure gage, and the thermometer are placed in the containers and wherein the pressure fluctuation source, the pressure signal receiver, the pressure gage, and the thermometer are connected to a signal analyzing unit.

Abstract: A method of detecting a marine gas seep that includes: deploying a local probe on or near the seafloor; producing bubbles in water near or within the local probe; detecting the bubbles; producing data indicating the relative concentration of dissolved gas in the water; and associating elevated dissolved gas concentrations with the presence of a nearby marine gas seep. Another aspect of the invention involves an apparatus configured to carry out the inventive method. Preferred embodiments of the invention utilize an ultrasonic transducer to both produce bubbles and detect them.

Abstract: A method of detecting a marine gas seep that includes: deploying a local probe on or near the seafloor; producing bubbles in water near or within the local probe; detecting the bubbles; producing data indicating the relative concentration of dissolved gas in the water; and associating elevated dissolved gas concentrations with the presence of a nearby marine gas seep. Another aspect of the invention involves an apparatus configured to carry out the inventive method. Preferred embodiments of the invention utilize an ultrasonic transducer to both produce bubbles and detect them.

Abstract: The present invention provides methods and related systems for efficiently detecting substances that are illegally transported in commerce, particularly by common carriers. The methods rely on a vacuum-induced collection of particulates from bulk material used to subvert or deter conventional detection methods. The disclosed methods are particularly adaptable for detecting illegal drugs such as cocaine but are also applicable to explosives and toxic materials. The methods may be employed for inspecting cargo shipments as well as smaller packages such as luggage and airline carry-on items.

Abstract: The method is used for determining a characteristic value for the binding force potential of paper fibers present in a fibrous suspension prepared for paper manufacture. According to the invention, the air content of the fibrous suspension is measured and this characteristic value derived therefrom. The correlation between the characteristic value and the air content ascertained can be discovered, e.g. by means of series of empirical measurements. With the aid of this method, e.g., the runnability on the paper machine can be assessed and corrected before breakdowns occur.

Abstract: The abundance of methane from a rock sample, recovered from a subsurface formation, is determined by submerging the rock sample in aqueous acid solution in a container for release of natural gas from the rock sample, and determining the amount of gas contained in bubbles which accumulate in the container as a measure of the abundance of methane released from the rock sample.

Abstract: Methods and devices are provided for “continuously”monitoring the concentration of an analyte in a host, i.e., for automatically measuring the concentration of an analyte at two or more points during a given time period. In the subject methods, substantially painless single use analyte concentration detection devices are employed to measure the concentration of the analyte of interest in the host, or portion thereof, e.g., interstitial fluid, where the measurements take place automatically according to a predetermined schedule. Devices provided by the subject methods have at least two different substantially painless single use analyte concentration measurement components which are under the control of a processing means that activates the measurement components according to a predetermined schedule. Also provided are systems and kits for use in practicing the subject methods.

Abstract: A thermostat array including an array of two or more capillary columns (10) or two or more channels in a microfabricated device is disclosed. A heat conductive material (12) surrounded each individual column or channel in array, each individual column or channel being thermally insulated from every other individual column or channel. One or more independently controlled heating or cooling elements (14) is positioned adjacent to individual columns or channels within the heat conductive material, each heating or cooling element being connected to a source of heating or cooling, and one or more independently controlled temperature sensing elements (16) is positioned adjacent to the individual columns or channels within the heat conductive material. Each temperature sensing element is connected to a temperature controller.

Abstract: A method for the control of actuation force in apparatus for determining entrained gas-phase content of process streams wherein the apparatus comprise compression of the process stream, measurement of the compressive behavior, and calculation of the volume of the entrained gas phase. In the apparatus, a piston device is rapidly translated into the process stream. The inertia of the liquid adjacent to the end of the piston causes the volume of fluid close to the end of the piston to be compressed by the movement of the piston. A pressure sensor integrally incorporated in the end of the piston measures the pressure pulse caused by the rapid movement of the piston. The pressure pulse is inversely proportional to entrained gas phase content. An accelerometer incorporated within the piston measures the acceleration of the piston.

Abstract: The present invention relates to an extraction, analysis and measuring method and system intended for constituents carried along by a well fluid during drilling operations. The system comprises in combination: draw-off means (4) for taking a volume of the fluid, extraction means (3) for extracting in vapour form the constituents contained in the fluid, comprising a space placed under underpressure, a transport line (14), sampling means (27) comprising a sampling loop allowing to take a determined amount of the vapors circulating in the line, distribution means (40) that inject the amount into analysis and measuring means (31), control means (33) for controlling the temperature of the sampling means so as to prevent condensation of said amount of vapors.

Abstract: The invention relates to a method and a measuring arrangement for measuring the gas content of a fluid (13). The fluid (13) comprises gas bubbles. In the method, microwave radiation (20) is transmitted through the fluid (13) and a signal (7) indicating the travel time, phase or amplitude of the radiation (20) is formed in a microwave measuring device (16), and a gas measuring equipment (18) determines the gas content of the fluid (13) by means of the signal (7).

Abstract: A method and apparatus for determining the volumetric gas content in a two-phase flow of a medium comprising a gas phase and a liquid phase which has an unknown flow shape are provided. Simple and reliable measurements are achieved by converting the two-phase flow into a droplet flow by vortexing the gas phase and the liquid phase, such that the determination of the volumetric gas content may be carried out in the droplet flow.

Abstract: A fluid filled transformer including a tank for containing at least primary and secondary windings, a radiator connected to the tank via top and bottom headers, a fluid disposed in the tank, a fluid circulation flow path including passages through the windings, radiator, headers, and at least a portion of the tank, and at least one diagnostic sensor disposed within the fluid circulation flow path for measuring properties of the fluid. By positioning the sensor within the circulation flow path, measured values are more reliable, accurate, and efficiently sensed.

Abstract: This invention relates to a measuring apparatus for measuring the gas loading of a liquid, comprising a measuring device which substantially consists of a piston pump, by means of which a sample quantity of the liquid is subjected to a reduced pressure in a measuring cylinder chamber and the dissolved amount of gas is thereby desorbed and can be determined via the gas law by changing the conditions of pressure and/or temperature in the cylinder chamber. The measuring apparatus is of particularly compact construction and for this purpose is provided with a servomotor as an actuating drive for the piston pump, which servomotor not only enables the reduced pressure to be generated in the measuring chamber but also ensures the return of the measured test sample from the measuring cylinder chamber after the measuring operation.

Abstract: A gas trap liberates subterranean gases entrained in drilling muds. The trap introduces a stripping gas into a flow of mud gas for liberating mud gases. The trap comprises a pair of opposing truncated right circular vessels and having a concentric bottom mud inlet, a side mud outlet and a gas collection port in the freeboard area, at the top. A stirrer depends vertically into the trap. The stirrer has radial tubes extending from its lower end and inlet ports at its top end for forming a continuous bore and flow passage therethrough. The radial tube ends are bevelled on the trailing edge. The trap is partially immersed in mud forming a mud level in the trap and a freeboard area above containing air. When rotated, the hollow shaft spins the mud, establishing a flow through the trap and forming a turbulent low pressure area at the bevels, drawing air down the shaft from the upper ports and injecting stripping air into the mud, all of which aids in liberating gases from the mud.

Abstract: Apparatus for measuring the contents of foreign matters in a flowing liquid, in particular a buoyant apparatus, which has a housing (1) of which at least one wall section (2) is intended to be brought into contact with the liquid, and has a preferably spherical arched outer side and in a hole (4) a sensor (9) for the foreign matter. The sensor (9) has on its outer side in the area of the hole (4) a diaphragm (10) which is permeable to the foreign matters that are to be measured and which is arched and flush with the outer side of the wall section (2). In order to increase the flow velocity in the area of the diaphragm so that no contaminations remain adhered to the outer side of the diaphragm (10) thus influencing its permeability and thereby the measuring ability of the apparatus, the arched outer side of the wall section (2) is equipped with guiding surfaces (11) for the liquid, which project from it and extend transversely to the hole.

Abstract: The invention relates to a method and a measuring arrangement for measuring the gas content of a fluid (13). The fluid (13) comprises gas bubbles. In the method, microwave radiation (20) is transmitted through the fluid (13) and a signal (7) indicating the travel time, phase or amplitude of the radiation (20) is formed in a microwave measuring device (16), and a gas measuring equipment (18) determines the gas content of the fluid (13) by means of the signal (7).

Abstract: An apparatus for monitoring one or more gas components in a fluid wherein either a) a sample gas obtained from the fluid is enriched in at least one target gas which is to be subjected to analysis; b) at least one target gas which is to be subjected to analysis is separated from a sample gas obtained from the fluid; or c) both.

Abstract: A method and apparatus for monitoring the degree of treatment of a material by a reactive fluid is monitored by reacting the unreacted fluid to produce a signal, eg. heat, and measuring the signal so produced.

Abstract: The method is used for locally testing underground soil contamination by determining the generation rate of a first contaminant fluid in porous soil. The method includes the steps of making a hole of known dimensions in the soil, with the hole defining a first and a second spaced-apart portions; covering the hole, so as to define a closed volume in the hole; constantly injecting a second fluid in the hole at a constant given flow rate at said first portion of the hole, while simultaneously collecting fluid samples at the above-mentioned constant given flow rate at the second portion of the hole; measuring the concentrations of the first contaminant fluid from the fluid samples collected at known time intervals; and computing the generation rate of the first contaminant fluid, from the known volume of the hole and from the concentrations previously measured and originating from samples collected at the known time intervals.

Abstract: A system for analyzing a content of at least one element of a contained atmosphere for soldering or tinning with a metal alloy, comprising: at least one sampling line for taking a gas sample from the contained atmosphere; at least one analyzer for analyzing the element; at least one coalescence filter located on the sampling line upstream of the analyzer; wherein the sampling line comprises a portion, located between the contained atmosphere and the coalescence filter, wherein the formation of cold spots which could cause precipitation of solid or pasty compounds in the line portion is prevented; a detector of a blockage in the sampling line between the enclosure and the analyzer.

Abstract: Apparatus and process is provided for establishing values of the quality of gaseous hydrocarbons in gas extracted from mud while drilling. Two rare earth sensors, without a coating, are exposed to the extracted gas. The first sensor is pre-calibrated and outputs a signal proportional to the relative concentration of light hydrocarbons. The second sensor is precalibrated and outputs a signal proportional to the relative concentration of heavy hydrocarbons. Preferably a second sensor is selected which, during calibration outputs a signal which is also proportional to the relative concentration of light hydrocarbons in a light sample gas and outputs a signal which is inversely proportional to the relative concentration of heavy hydrocarbons in a heavy sample gas. The difference of the two signals is obtained and is compared to the first sensor signal as being indicative of the quality of any hydrocarbons present in the extracted gases.

Abstract: Detection of an evolving or diffusing gaseous substance emanating from an irradiated or thermolyzed layer of polymeric composition in semiconductor processing or similar processes is disclosed. The evolving or diffusing gaseous substance is detected by spatially disposing from the irradiated or thermolyzed layer a detector layer that includes a compound having leaving groups that are sensitive to the gaseous substance being detected.

Abstract: A method and apparatus for monitoring the degree of treatment of a material by a reactive fluid is monitored by reacting the unreacted fluid to produce a signal, eg. heat, and measuring the signal so produced.

Abstract: Apparatus and method for detecting the dew point or bubble point phase transition in fluid. The apparatus used comprises a piezoelectric crystal sensor and a signal analyser. The phase transition of the fluid is measured by monitoring, directly or indirectly, change in the resonant frequency of the piezoelectric crystal sensor while said one of the temperature and pressure is varied, so as to detect a substantial change in said resonant frequency and/or in the rate of change in resonant frequency with change in the varying one of the temperature and pressure.

Abstract: A sampling device for use downhole is provided comprising a hollow body (24) having a fluid inlet port (26) for fluid entry to the interior thereof, characterised by a gas extraction system (64) associated with the hollow body (24) and capable of securing as a non-volatile component at least part of a volatile component dissolved in a fluid entering the hollow body (24), the gas extraction system being removable therefrom to allow quantitative analysis of the non-volatile component to be undertaken. The gas extraction system (64) is placed in a supplementary chamber (46) having an inlet (50) and an outlet (52) which is attached to the hollow body and through which fluid passes to enter the hollow body. The gas extraction system is iron oxide to fix sulphur from volatile hydrogen sulphide for later analysis.