Abstract: A pressure sensor device 10 comprises three layers 11a, 12 and 11b of silicon, fusion-bonded together. The outer layers 11a and 11b form a sealed housing around the central layer 12 to which they are bonded, and in use a cavity 13 between the housing 11a, 11b and central layer 12 is evacuated. The sensor device 10 is normally placed inside a component for containment of a pressurised fluid (not shown). Due to the cross-sectional shape of the device 10, pressure exerted by the fluid causes the layers 11a and 11b to flex inwardly in the region of minimum cross-sectional dimension and thereby outwardly in the region of maximum cross-sectional dimension, thereby is placing under tension a balanced twin beam vibratable element 16 on the central layer 12. The tension across the vibratable element affects its resonant frequency of vibration.

Abstract: A thermocouple probe 10 suitable for use in a gas turbine engine comprises a thermocouple element 12 which is coaxially arranged inside a protective sheath 16. The thermocouple element 12 is resiliently supported by a helical member 18 which insulates the element 12 from deleterious vibrations induced in the sheath 16. In use, the thermocouple probe 10 projects through an aperture 30 in the casing 32 of a gas chamber 34. Vibrations in the probe 10 are further reduced by ensuring that the longitudinal axis AA of the probe is angularly offset from the central axis BB of the aperture 30, such that the outer periphery of the sheath 16 is in contact with the inner periphery of the aperture 30 in two diametrically opposite and axially offset locations.

Abstract: A thermocouple probe 10 suitable for use in a gas turbine engine comprises a thermocouple element 12 which is coaxially arranged inside a protective sheath 16. The thermocouple element 12 is resiliently supported by a helical member 18 which insulates the element 12 from deleterious vibrations induced in the sheath 16. In use, the thermocouple probe 10 projects through an aperture 30 in the casing 32 of a gas chamber 34. Vibrations in the probe 10 are further reduced by ensuring that the longitudinal axis AA of the probe is angularly offset from the central axis BB of the aperture 30, such that the outer periphery of the sheath 16 is in contact with the inner periphery of the aperture 30 in two diametrically opposite and axially offset locations.