Patent GB-1141019-A (GB)
Title: Improvements in fluid-operated frequency sensing converter circuit
IPC: F15C1/14
Filed: 1966-05-04
Abstract: 1,141,019. Pure fluid devices; speed governors. GENERAL ELECTRIC CO. May 4, 1966 [May 19, 1965; Oct.21, 1965], No.19604/66. Headings G3B and G3H. A fluid frequency-analogue converter circuit, which may form a turbine speed governor circuit, comprises a fluid input to a circuit 20 whose frequency is proportioned to the rotational speed of inclined plate 15 driven from the turbine. The sinusoidal signal at the input chamber 21 of the circuit 20 is fed through two chambers 24, 25 to control nozzles 26, 27 to act on a power jet 30. The channel 25 is of a relatively large volume to attenuate the signal and provide a constant pressure signal at the nozzle 27. The output signal at 31 is a squarewave signal at a frequency equal to the input and this is fed to the input chamber 41 of a "derivative" circuit 40. Channels 44, 45 lead from the ' chamber 41 to control nozzles 48, 49. The channel 45 is relatively large but smaller than the channel 25 of the previous stage, so that a pressure in chamber 41 is effective immediately at nozzle 48 but with a time delay at nozzle 49. The outputs 50, 51 are thus in the form of a differentiated squarewave and these outputs form the input signals to nozzles 63, 64 of a full-wave rectifier 60 having a power jet input 66 and a single output 62. The output signal from rectifier 60 is fed through a filter 70 to remove the ripple and thus provide a pressure signal proportioned to the speed. The output pressure signal may be compared with a desired speed signal in a proportional amplifier 80 which gives a differential output at 77, 78 proportional to the difference between the desired and actual speed. In a modification, two frequency signals, 180 degrees out of phase, are fed to digital amplifier to provide two squarewave outputs which are fed through capacitors to a rectifier and filter. In a further modification, a frequency signal acts in opposition to a fixed bias signal in a proportional amplifier to provide a squarewave output which is fed through branch lines, one of which contains a capacitor, to a rectifier and filter whose output is inversely proportional to the input. 1,141,021. Photographic process. NATIONAL RESEARCH DEVELOPMENT CORP. Feb. 7, 1966 [Dec. 1, 1964], No.48738/64. Heading G2C. A visible photographic image is obtained by maintaining a layer of a metal halide having a crystalline layer structure, but excluding lead iodide and cadmium iodide, at a temperature sufficient to enable photo-decomposition to take place and exposing imagewise to ionising radiation. Metal halides specified are cuprous iodide and cadmium bromide. In a further embodiment, a composite layer of any metal halide having a crystalline layer structure, e.g. lead iodide, and silver iodide is similarly exposed to obtain a visible image. A visible image thus obtained may be intensified by evaporating a thin film of metal on to the image, e.g. lead iodide image is coated with a thin film of zinc which forms an opaque layer in decomposed areas but reacts with lead iodide to form a yellow transparent film in undecomposed areas. The latter may be removed with water. Reference has been directed by the Comptroller to Specification 1,045,487.