Abstract: A combustible gas sensor comprises four glass insulated radially extended and symmetrical temperature sensitive elements which are coated with a porous ceramic but only two elements having a catalyst. The sensor is mounted inside a temperature controlled reactor vessel in a region of no temperature gradient into which a combustible gas mixture is admitted and reacted on the catalytic surfaces. The change in the resistance of the elements under the catalyst is a measure of the concentration of the combustible gas.

Abstract: A method and apparatus for determining the proportion of a paramagnetic gas in a mixture of gases is disclosed. There is provided an element which is able to oscillate in a magnetic field. A force acting on the element due to the presence of paramagnetic gas in the magnetic field changes according to the concentration of paramagnetic gas present. This change in force affects parameters of the oscillation such as damping and frequency, which may be monitored thereby to determine the concentration of paramagnetic gas present.

Abstract: A miniature source of modulated infra-red energy comprises a very thin heated wire strip (11) of low mass, mounted in a tensioned state by means of two resilient members (18), and a reflector (15) positioned behind the wire (11) so as to enhance the radiated energy. The source is hermetically sealed in an inert atmosphere with a cap (20). The cap (20) has an aperture (16) through which the energy emerges, this is sealed either with a window or a filter (17) if a specific wavelength is desired.

Abstract: A gas testing apparatus comprising a body (13, 14) defining a chamber (7), means (2, 3) for creating a magnetic field within the chamber in a first direction, a test body (20), means (19) for mounting the test body (20) for rotation about an axis parallel to the direction of the magnetic field, and gas inlet (9) and outlet (10) means for allowing gas flow through the chamber (7), characterised in that the gas inlet means (9) are arranged and disposed to supply gas to the chamber from two positions at opposite sides of the chamber whereby gas flow from each of the two positions will be parallel to the direction of the magnetic field but in opposition in order to minimize errors resulting from gas flow upon the test body. The chamber is of small volume i.e. less than 0.6 ml which enables the apparatus to be used for preliminary monitoring.

Abstract: Gas testing apparatus comprises a gas chamber wherein a test body surrounded by a single turn electrical conductor is suspended by a metal strip in a non-uniform and non-symmetrical magnetic field which is formulated by especially shaped pole pieces which could, in one form, by permanent magnets. The test body is deflected from the initial position it takes when a reference gas is in the cell, by the admittance of a gas mixture of which is paramagnetic gas is one constituent. The deflection is sensed by an optical system comprising a light source, a mirror on the test body and a pair of photocells. The output of the photocells feeds an amplifier system, which in turn feeds the single turn coil by a current of an adequate value such that it stops the test body from moving from its initial position and hence is proportional to the partial pressure of the paramagnetic gas in the sample.

Abstract: A device for monitoring a component in a fluid mixture includes a tube 1, the bore of which is divided into two chambers by a disc of solid electrolyte 1a. The electrolyte is chosen to have a conducting ion related to the component to be measured. Suspension device in the form of two resilient diaphragms 7 suspend the tube within a housing including a frame member 16 and end caps 15. Each of the diaphragms is sealed at its interface 9 with the housing, and at its interface 6 with an end of the tube. Heater 10, 11 are provided to alter the temperature of the component in each chamber and inlet 21 and outlet 22 allow fluid to enter and leave the chambers.The e.m.f. between electrodes 2 is monitored and information about the fluid mixture can be obtained depending on the temperature of the mixture sensed by a thermocouple arrangement 3.

Abstract: An oxygen sensor having a solid electrolyte tube and partition. A heater is tightly wound along the length of the tube, which is divided into two equal chambers by the partition, and thermocouples are fixed to either side of the partition by layers of metallic particles. An insulating case and flame trap may be provided for the sensor.