Abstract: A louvred reflector 10 (FIG. 1) comprises an array of wholly or partially reflecting louvres of which two adjacent louvres 12,13 are shown in the Figure. Each said louvre, when viewed short-edge on as shown in the Figure, comprises an inclined downwardly-facing concave first section 15 and a lower, less-steeply inclined, downwardly-facing concave second section 16. Light reflected by the louvres is downwardly directed over a considerable angular range to produce generally uniform illumination on either side of the reflector. In a second embodiment, the reflected light is directed to only one side of the reflector.

Abstract: A pressure sensing device having a separator diaphragm through which pressure is transmitted from a working fluid to a liquid within a first part of the device and a transducer for measuring the pressure of the liquid or the difference between the pressure of the liquid and the pressure of an external fluid. A pressure overload diaphragm comprises a dished plate which forms part of a side wall of the first part of the device and has an inner section of the plate extending inwardly of that part. The overload diaphragm is inflexible or substantially inflexible over a working range of differential pressures applied thereto but the inner section thereof moves outwardly of the first part of the device if the differential pressure exceeds a predetermined value.