Abstract: A gas storage container, such as a gas cylinder, is filled with a gas mixture comprising a first gas and a second gas under pressure by feeding a liquid/solid mixture comprising liquefied first gas and solidified second gas into the gas storage container; closing the gas storage container to the passage of gas into or out from the container; and allowing said liquefied first gas and said solidified second gas to become gaseous within said closed gas storage container. Such a process is easier and more energy efficient as compared to direct compression processes, and is safer and results in less wastage as compared to direct liquid injection processes.

Abstract: There is provided a meter for measuring the molecular weight of a gas, the meter comprising a housing having an inlet and an interior for receiving said gas to be measured, a sensor assembly comprising a high-frequency planar piezoelectric crystal oscillator located within said housing so that, in use, the piezoelectric crystal oscillator is in contact with said gas, said sensor assembly being arranged: to drive the piezoelectric crystal oscillator such that the piezoelectric crystal oscillator resonates at a single resonant frequency; to measure said single resonant frequency of said piezoelectric crystal oscillator to determine the density of gas; and to determine from the density, determined or pre-determined pressure of the gas and determined or pre-determined temperature of the gas, the molecular weight of the gas.

Abstract: There is provided a meter (200; 350) for measuring the mass flow rate of a gas. The meter comprises a conduit (206) through which the gas flows in use. The conduit has a flow restriction orifice (212) through which choked flow occurs in use. The flow restriction orifice divides the conduit into an upstream portion (214) upstream of said orifice and a downstream portion (216) downstream of said orifice. The meter further comprises a sensor assembly (204), the sensor assembly including a piezoelectric crystal oscillator (218) in said upstream portion such that said piezoelectric oscillator is in contact with said gas when the meter in use. The sensor assembly is arranged: to drive the piezoelectric crystal oscillator such that the piezoelectric crystal oscillator resonates at a resonant frequency; to measure said resonant frequency of said piezoelectric crystal oscillator; and to determine, from the resonant frequency, the mass flow rate through the orifice.

Abstract: There is provided a pressure gauge for measuring the pressure of a gas. The pressure gauge comprises a housing connectable to the gas source and comprising an interior which is, in use, in communication with said gas. The pressure gauge further comprising a sensor assembly located within said housing and including a piezoelectric oscillator which, in use, is located in contact with said gas, said sensor assembly being arranged to measure the oscillation frequency of said piezoelectric oscillator in said gas and configured to determine, from the frequency measurement and the known temperature and known molecular weight of the gas, the pressure of the gas. By providing such an arrangement, an overpressure proof yet accurate pressure gauge can be provided. This is in contrast to conventional gauges which are damaged permanently by overpressure situations.

Abstract: There is provided a method of and apparatus for, measuring the mass of a gas under pressure using a piezoelectric oscillator. The gas is contained within a pressure vessel (100) having a fixed internal volume (V) and the piezoelectric oscillator (202) is immersed in the gas within the pressure vessel (100). The method comprises: a) utilising said piezoelectric oscillator (202) to measure the density of the gas within the high-pressure vessel (100); b) determining, from the density measurement and from the internal volume (V) of said pressure vessel, the mass of the gas within the pressure vessel (100). By providing such a method, the true contents (i.e. mass) of fluid in a pressure vessel such as a cylinder can be measured directly without the need to compensate for factors such as temperature or compressibility. This allows a determination of mass through direct derivation from the density of the gas in the cylinder, reducing the need for additional sensors or complex calculations to be performed.

Abstract: A volume flow controller (1) for controlling the flow of a gas mixture of variable proportions through a conduit (3) has a valve means (5) for regulating the flow of gas through the conduit, a drive means (9) for driving the valve means, a volumetric flow meter (7), such as a Pelton wheel, for measuring the flow of gas through the conduit, which provides a feedback signal (29) for comparison with a setpoint signal (17) in an amplifier (15) which generates an adjustment signal (11) which is fed to the drive means.

Abstract: A system for providing a high purity acetylene comprising 100 ppm or less solvent to a point of use comprising a storage vessel that houses an acetylene feed steam comprising acetylene and solvent; a cooling system that maintains the storage vessel and provides the acetylene feed stream at a temperature ranging from 20° C. to ?50° C.; and a purifier in fluid communication with the storage vessel wherein the acetylene feed stream is introduced into the purifier at a temperature ranging from ?50° C. to 30° C. to remove at least a portion of the solvent contained therein and provide the high purity acetylene.

Abstract: A system and a process for providing acetylene, preferably at a high purity level (e.g., comprising 100 parts per million (“ppm”), or 10 ppm, or 1 ppm, or 100 parts per billion (“ppb”), or 10 ppb, or 1 ppb or less of solvent), to a point of use, such as a semiconductor manufacturing process, is described herein. In one aspect, there is provided a process for providing a process for providing a high purity acetylene comprising 100 ppm or less solvent to a point of use comprising: providing an acetylene feed stream comprising acetylene and solvent at a temperature ranging from 20° C. to ?50° C.; and introducing the acetylene feed stream to a purifier at a temperature ranging from ?50° C. to 30° C. to remove at least a portion of the solvent contained therein and provide the high purity acetylene.

Abstract: A volume flow controller (1) for controlling the flow of a gas mixture of variable proportions through a conduit (3) has a valve means (5) for regulating the flow of gas through the conduit, a drive means (9) for driving the valve means, a volumetric flow meter (7), such as a Pelton wheel, for measuring the flow of gas through the conduit, which provides a feedback signal (29) for comparison with a setpoint signal (17) in an amplifier (15) which generates an adjustment signal (11) which is fed to the drive means.

Abstract: A system and a process for providing acetylene, preferably at a high purity level (e.g., comprising 100 parts per million (“ppm”), or 10 ppm, or 1 ppm, or 100 parts per billion (“ppb”), or 10 ppb, or 1 ppb or less of solvent), to a point of use, such as a semiconductor manufacturing process, is described herein. In one aspect, there is provided a process for providing a process for providing a high purity acetylene comprising 100 ppm or less solvent to a point of use comprising: providing an acetylene feed stream comprising acetylene and solvent at a temperature ranging from 20° C. to ?50° C.; and introducing the acetylene feed stream to a purifier at a temperature ranging from ?50° C. to 30° C. to remove at least a portion of the solvent contained therein and provide the high purity acetylene.

Abstract: A volume flow controller (1) for controlling the flow of a gas mixture of variable proportions through a conduit (3) has a valve means (5) for regulating the flow of gas through the conduit, a drive means (9) for driving the valve means, a volumetric flow meter (7), such as a Pelton wheel, for measuring the flow of gas through the conduit, which provides a feedback signal (29) for comparison with a setpoint signal (17) in an amplifier (15) which generates an adjustment signal (11) which is fed to the drive means.

Abstract: Gas is delivered to a locus from a gas delivery device (1), which is spaced from the locus and comprises an inner pipe (2) and an outer pipe (3) axisymmetrical with and surrounding said inner pipe (2) to form an annular conduit (4). A first gas is fed to the inner pipe to exit as a laminar flow jet impinging on the locus and a second gas is fed to the annular conduit to exit as a turbulent flow annular sleeve surrounding and constraining diffusion of said jet. In a preferred embodiment, normoxic air is fed to both the inner pipe and the conduit and oxygen is introduced into the inner pipe at an intermediate location so that the jet is oxygen-enriched air for inhalation by a user at the locus.

Abstract: The concentration of xenon, in a medical gas mixture of xenon as an active component with a known composition of oxygen and, optionally, nitrogen and/or helium recirculating through a medical device (103) in which carbon dioxide is introduced into the mixture, is monitored by removal (135, 133) of carbon dioxide downstream of the medical device (103) and subsequently passing the carbon dioxide-free gas through an ultrasonic gas analyser (143) upstream of the medical device. The gas analyzer determines the xenon concentration by measuring the time delay between transmission of an ultrahigh frequency ultrasonic pulse of at least 100 kHz axially through the sample chamber from a location at one end thereof and reflection of said pulse axially from the other end of the sample chamber back to said location. An analyser of novel construction is disclosed.

Abstract: A container (1) having a first compartment (3) and a second compartment (5) separated by a movable gas impermeable partition (7) is used for storing and dispensing a gas for use in a process and receiving and storing a gas recovered from the process. Fresh gas is dispensed (9) from the first compartment (3) for use in a process and recovered gas is fed (11) to the second compartment (5), whereby a volume of the second gas displaces a volume of the first gas by movement of the partition (7) to enlarge the second compartment (5) relative to the first compartment (3).

Abstract: A fluid control system for use with toxic or corrosive gases (for example) has been provided that includes a fluid pressure regulator comprising a fluid inlet; a fluid outlet; a first fluid flow path between the fluid inlet and the fluid outlet; a valve seat positioned in the first fluid flow path and dividing the fluid inlet and the fluid outlet; a valve element regulating flow through the valve seat; a generally cylindrical membrane defining an inflatable fluid cavity that moves axially, responsive to inflation; a wall portion of the cavity that moves responsive to inflation and deflation of the cavity; a second fluid flow path communicating between the cavity and a source of pressure outside the cavity; and a link transmitting the movement of the wall portion to the valve element, thereby moving the valve element with respect to the valve seat responsive to inflation and deflation of the cavity.

Abstract: A fluid control system for use with toxic or corrosive gases (for example) has been provided that includes a fluid pressure regulator comprising a fluid inlet; a fluid outlet; a first fluid flow path between the fluid inlet and the fluid outlet; a valve seat positioned in the first fluid flow path and dividing the fluid inlet and the fluid outlet; a valve element regulating flow through the valve seat; a generally cylindrical membrane defining an inflatable fluid cavity that moves axially, responsive to inflation; a wall portion of the cavity that moves responsive to inflation and deflation of the cavity; a second fluid flow path communicating between the cavity and a source of pressure outside the cavity; and a link transmitting the movement of the wall portion to the valve element, thereby moving the valve element with respect to the valve seat responsive to inflation and deflation of the cavity.

Abstract: A fluid storage and purification system which comprises a cylindrical vessel having an exterior and an interior containing a fluid, the vessel having a first end and a second end, wherein the first end has a cylindrical neck, and wherein the inside diameter of the cylindrical neck is smaller than the inside diameter of the vessel; a helical purifier tube assembly which is disposed in the interior of the vessel, wherein the maximum outer diameter of the helical purifier tube assembly is larger than the inside diameter of the cylindrical neck, wherein the tube has a first end and a second end, and wherein the first end is in fluid flow communication with the interior of the vessel; and a valve comprising a body, an inlet, and an outlet. The valve body can be sealably connected to and disconnected from the cylindrical neck and the second end of the helical purifier tube assembly can be connected to the inlet of the valve.

Abstract: A noise reduction circuit useful as a clock restoration circuit includes a DC removal circuit for removing a DC level from an input pulse train, an integrator for integrating the input pulse train after a DC level has been removed, a comparator for comparing the integrator output with a threshold value (Vmp) to detect for a missing pulse, a pulse generator inserting into the input pulse train an additional pulse delayed with respect to any missing pulse, and an output circuit for generating an output pulse train from the integrator output.