Abstract: Emergency breathing equipment intended to provide short term life support by ducting breathable gas from a small capacity source to a user via a restricted flow path that allows only limited flow rates so as to prevent hyperventilation and wastage of breathable gas is characterised by a demand valve having the poppet controlled by a demand pressure-sensing diaphragm to control an inhalation flow path, the diaphragm also controlling an exhalation flow path so as to switch the user between said flow paths by opening one and closing the other, as it moves between two positions under the influence of demand pressure. The equipment is also characterised by a reactive pressure regulator for the breathable gas and having its delivery pressure switchable by a trigger element that in an installed position unloads the reaction member so as to provide zero delivery pressure, withdrawal of the trigger element allowing the reaction load to operate to set a fixed positive delivery pressure.

Abstract: An automatic valve for inflating an inflatable article, includes a pin for piercing an operculum seal of a container for a compressed gas, a spring for urging the pin in a first direction to pierce the operculum seal of a compressed gas container, an arming mechanism for causing movement of the pin against the spring into an armed position and a latching mechanism including a pressurizable compartment for latching the pin in the armed position. The latching mechanism is arranged so as to release the pin on release of pressure of the pressurizable compartment, and a release mechanism for causing the release of pressure from the pressurizable compartment on immersion of the valve in water.

Abstract: A fluid control valve having a discharge port controlled by an obturator is characterised by the discharge port being shaped to cause a marked drop in back pressure at a small critical opening distance of the obturator from the port, thereby to provide impetus to initiating discharge. The discharge port has effectively a concave surrounding surface for this purpose. To achieve good sealing with light loading, the port preferably also has a convex surface immediately surrounding its orifice. The preferred configuration is a convex surface bounded by a wall. The obturator may be resiliently loaded to enable its response to dynamic effects of fluid flow to enhance opening "lift". The obturator may be, e.g. a lever, a diaphragm or the armature of a solenoid.

Abstract: A sealing strip for preventing or reducing gas flow in an unwanted direction through an elongate gap, such as the gap between a door or window and its associated frame, and comprising a lip portion extending along the length of the strip and an attachment portion extending along the length of the strip for securing the strip in position adjacent to one side of such a gap, is characterized by said lip portion being flexible and capable of being deformed into sealing engagement with the opposite side of the gap, at least partly to seal the gap, by gas flow into the gap in the unwanted direction. A method of preventing or reducing gas flow in an unwanted direction through such a gap by using such a strip is also disclosed.

Abstract: A pressure fluid control valve has a seal comprising a sealing element housed in a recess that is provided with a vent arranged automatically to relieve pressure in the recess if the sealing element is subject to excessive distortion.

Abstract: A sphincter valve for the control of fluid flow is characterized by a pair of diaphragms spaced apart from one another and having different effective areas. The smaller-area diaphragm is adapted for deflection into sealing engagement with a seating to control fluid flow thereacross, whereas the larger-area diaphragm is arranged to be exposed to operating (pilot or signal) fluid to be deflected thereby towards the smaller-area diaphragm. A thrust transmission element disposed between the diaphragms serves to deflect the smaller-area diaphragm in response to deflection of the larger-area diaphragm.

Abstract: An interconnecting unit for reliably establishing compact and readily rearrangeable connections between the components of a fluid pressure-operated system comprises a matrix block with primary and secondary sets of non-intersecting passages adapted for connection to system components has linking passages joining each primary passage with every secondary passage, communication and flow-control between the so-joined passages being determined by the introduction of flow-controlling plug members selectively into the associated linking passages.