Abstract: A fluid pressure intensifier device particularly suited for intensifying the pressure of a gas has a plurality of piston and cylinder compression stages of sequentially reducing volume connected by flow passages (FIG. 5b) for conducting fluid to be pressure intensified sequentially through the compression stages. Individual pressure fluid powered driving mechanisms for each piston or cylinder compression stage comprise driving piston and cylinder assemblies controlled to operate in sequence by a rotatable port plate. The port plate is rotatable by a positive displacement pressure fluid motor actuated by the pressure fluid powering the driving piston and cylinder assemblies, the outer gear of the motor being constituted by the rotatable port plate.

Abstract: A flueric partial pressure sensor (10) includes a flueric bridge sensor (10a) having two bridge legs (11, 12) adapted for sensing a reference-gas and a sample-gas. A linear resistor (14, 15) and an orifice resistor (16, 17) are incorporated in each leg and arranged to cause asymmetric flow rates therethrough. Inlets to the two bridge legs are subject to a datum pressure within a datum pressure chamber (38) so that a change of datum pressure automatically changes control signals output by the sensor. The partial pressure sensor is disclosed in combination with a molecular sieve type gas concentration system (24) in an on-board oxygen enrichment of air system for an aircraft and enables the oxygen concentration in oxygen enriched air delivered by the system to be appropriate to breathing requirement at an altitude intermediate aircraft cabin and ambient atmospheric pressures.

Abstract: A molecular sieve type gas separation system capable of delivering oxygen-enriched air by increasing the oxygen content of air fed to the system has control means including a valve arrangement associated with each sieve bed for cyclically subjecting each bed to a charge/adsorption on-stream phase followed by a purge/desorption regeneration phase. During the regeneration phase of each sieve bed the gas pressure in the bed at least substantially equals the ambient atmospheric pressure or a pressure related thereto such as the ambient pressure of an outlet to which the oxygen-enriched air is being delivered and, for a predetermined range of outlet ambient pressure, the overall cycle time and the relative durations of the phases are fixed at values such that the oxygen content of air delivered by the system remains within physiologically acceptable limits for breathing.

Abstract: In supplying a high volume flow of oxygen-enriched air from a molecular sieve type gas separation system, two sets of molecular sieve beds are coupled in parallel. The beds and of each bed set are cyclically subjected to a charge/adsorption on-stream phase followed by a purge/desorption regeneration phase and are controlled to operate in overlapping sequence with respect to each other. At the same time the corresponding beds are controlled to operate in antiphase relationship to each other.

Abstract: A gas flow controller 10 for use with a molecular sieve type oxygen enrichment of air system 5 delivering oxygen enriched air for breathing by aircrew ensures that a constant preset quantity of product gas in the form of oxygen enriched air flows from the system 5 so that it performs under varying demand conditions and varying air supply conditions to maintain desired levels of oxygen concentration in the oxygen enriched air delivered to the aircrew by means of a demand regulator 6 and a breathing mask 7. A servo-operated valve means 20 bleeds air from downstream of a venturi section 15 provided between in the inlet 13 and outlet 14 of a gas flow duct 12 in the body 11 of the controller 10. The servo-operated valve means 20 is regulated by an actuator means 29 responsive to pressure difference through the venturi section 15.

Abstract: Signal output means (11) responsive to gas flow and particularly suited for use in gas flow indicator apparatus (10), has first and second pressure-datum valves (24, 25) arranged in downstream order in a gas conduit (16), the second pressure-datum valve (25) being arranged to open at a lower pressure difference than the first pressure-datum valve (24). A flueric amplifier (15) has a power jet port (28) connected to the gas conduit (16) on the upstream side of the first pressure-datum valve (24), opposed control pressure ports (26, 27) connected respectively to a chamber (22) formed between the first and second pressure-datum valves (24, 25) and to the gas conduit (16) downstream of the second pressure-datum valve (25), and a vent port (30) also connected to the gas conduit (16) downstream of the second pressure-datum valve (25). A pressure signal output by the flueric amplifier (15) in response to gas flow through the conduit (16) may be used to trigger a visual or audio warning device (14).

Abstract: A deep diving breathing system in which a breathable gas mixture is circulated through a diving helmet by a push-pull pump includes an inlet flow control valve, an outlet gas flow regulator valve, and a bleed valve. The bleed valve operates in response to the pressure of gas flowing from the outlet gas flow regulator valve to bleed gas from a gas supply line upstream of the inlet flow control valve. The system facilitates diving operations from a diving bell at a range of depths and recovery of helium in a helium-oxygen breathing gas mixture.

Abstract: A flueric partial pressure sensor includes a flueric bridge having two bridge legs adapted for sensing a reference-gas and sample-gas mixture. A linear resistor and an orifice resistor are incorporated in each of the bridge legs which are conjoined to discharge from a single outlet. The resistors are arranged to provide an asymmetric balance of the flow rates through the bridge legs. The asymmetric balance is selected so that in operation a constant pressure output signal is generated for a chosen partial pressure of a constituent gas of the sample-gas mixture in varying absolute pressure conditions such as changes in altitude. Respective pressure signal outlets connected one with each bridge leg at a position between the linear resistor and the orifice resistor are used to effect control of a flueric laminar flow proportional amplifier. Outputs from the flueric amplifier may be used to regulate a fluid mixing valve shown in FIG. 3, or to effect switching of an indicator device shown in FIG. 4.

Abstract: A molecular sieve type gas separation system capable of delivering a product gas of controlled variable composition and being especially useful for the production of oxygen-enriched air as breathable gas for aircrew, has an apparatus for controlling the regeneration of the or each sieve bed so as to achieve delivery of the product gas with a constituent concentration which is variably selectable within a predetermined range of values.

Abstract: The invention provides a breathable gas regulator of the demand type for use with a low supply pressure (10 p.s.i or less) gas source.The regulator requires no greater demand effort on the part of a user than is required with present-day regulators of the same type which operate with much higher pressure (70 p.s.i. and above) gas sources, and it requires ducts, diaphragms and valves of no greater size than are required by present-day regulators. This is achieved by inclusion of a servo valve that is actuated by a fluidic amplifier arrangement responsive to the user's breathing pressure.In an embodiment of the invention particularly suited for use by an aviator, the regulator includes a pneumatically operated mixing valve arrangement for automatically varying, according to altitude, the proportions of, say, oxygen and air supplied to the demand valve of the regulator, and the mixing valve arrangement includes a fluidic gas concentration sensor.

Abstract: An environmental control system comprises a working gas circuit including a compressor-expander arrangement and first heat exchange means by which the working gas is conditioned before being passed to second heat exchange means connected in the circuit in heat exchange relationship with an environment to be controlled. The working gas is provided with means for regulating the mass of working gas in the circuit in response to the conditioning demand on the system. One such regulating means comprises an inlet path for admitting working gas to the circuit and an outlet path for removing working gas from the circuit.

Abstract: A wall structure for use in forming part of an enclosure that is subject to high pressure differential between its external and internal environments comprises tubing that has been flattened over two diametrically opposed areas and helically wound so as to be contiguous along the flattened areas. The interior of the tubing is filled with a substantially incompressible flexible medium. Means are provided for pressurizing the flexible medium, at least during periods of operation when the enclosure is subjected to a substantial pressure difference between its external and internal environments, so as to balance some of the loads acting on the wall structure due to the pressure differential. The wall structure is particularly suitable for use in forming parts of a deep diving suit or other deep diving and submersible enclosures.