Abstract: Apparatus (1) for imaging an object (4) on the remote side of a barrier (6). The apparatus has source means (2) for scanning the object (4) through the barrier (6) with radiation and mask means (8) having at a least one radiation transparent area wherein the radiation from the source is masked thereby to project on to the object (4) at least one scanning beam of radiation. The apparatus (1) also has detector means (10) for detecting radiation reflected from any scanned point on the object (4) and image generation means for generating an image of the object (4) from the detected radiation.

Abstract: A sealing system for a high pressure fuel cylinder has an inner seal and an outer seal sealing an insert into a boss of the cylinder. Permeation rates as a result of the differential pressures across the seals are balanced across both the inner and outer seals to maintain a constant pressure in an intermediate space between the seals. Permeation is balanced by selecting suitable seal materials or by seal geometry or by providing a pressure relief device to the intermediate space to release excess pressure built up in the intermediate space beyond a desired intermediate pressure. Maintaining the intermediate pressure lower than the cylinder pressure and higher than atmospheric pressure results in lower pressure differentials across the seals, extending the seal life. A pressure switch or gauge is provided to monitor the pressure in the intermediate space. Changes in the pressure are indicative of a leak in one or both of the seals.

Abstract: Apparatus (1) for imaging an object (4) on the remote side of a barrier (6). The apparatus has source means (2) for scanning the object (4) through the barrier (6) with radiation and mask means (8) having at a least one radiation transparent area wherein the radiation from the source is masked thereby to project on to the object (4) at least one scanning beam of radiation. The apparatus (1) also has detector means (10) for detecting radiation reflected from any scanned point on the object (4) and image generation means for generating an image of the object (4) from the detected radiation.