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Ultrasonic thickness meter is explosion-proof
Ultrasonic and acoustic sensors help to optimize petrol engine performance Non-intrusive sensors are being used with a modular, microprocessor-based engine timing system developed by Froude Consine to increase fuel economy and reduce emission levels from patrol and diesel engines. Data from ultrasonic and acoustic transducers are fed to a control panel which continuously monitors and displays timing angle and engine speed, enabling 'end-of-line' testing during engine manufacture. Optimum engine timing involves igniting the fuel in the piston chamber at the particular point in the piston compression cycle which ensures that all of the fuel is burnt -- this point in the cycle is determined with reference to a position called top dead centre (TDC). The two requirements of this timing system, as far as engine production was concerned, were .to establish TDC, and to establish the exact point where fuel injection (diesel) or spark ignition (petrol) starts. Ultrasonic sensors are employed to determine TDC location. Probes are oil-coupled to the cylinder block and positioned along the axis of piston travel. Since the piston rings are the only parts of the piston in close contact with the cylinder bore the ultrasonic signal is altered as the rings pass the focal point of the
probe. Ultrasonic pulses are emitted at a fixed angular interval of crank rotation such as to map at O.1° intervals. To compensate for fluctuations in engine speed the unit operates in conjunction with an angular reference such as flywheel teeth or a shaft encoder. To determine the fuel injection point, the discrete sonic frequency emitted as this occurs is detected by an acoustic microphone mounted a few millimetres from the injector. For spark ignition engines, a transducer is placed around one of the high-tension electrical leads. Froude Consine has spent three years and £250 000 developing the system. As well as eliminating the need for intrusive, potentially damaging, timing operations, the company says the system produces repeatable results with an accuracy within that of mechanical measurements. Four areas of application in particular are forseen: production engine timing; REtD; automated timing measurement, by interfacing to computerized data acquisition and control systems; and in-service maintenance, for which a simplified system will be available.
Froude Consine Ltd, Gregory's Bank, Worcester WR3 8AD, UK
Built into • cast aluminium housing, the D M 2 Ex ultrasonic thickness gauge
Ultrasonic thickness meter is explosion-proof An ultrasonic thickness meter that can be operated safely in explosive environments and is spray waterproof has been introduced by Wells-Krautkramer. Designated DM2-Ex, the instrument is a version of the pocket-size DM2 wall thickness meter and opens up new areas, such as mines, to ultrasonic measurement and corrosion detection. A lightweight cast aluminium housing provides detonation protection to VDE 0170:(Sch) s.i. for mines and to VDE 0171 :(Ex) s.i. G1-G5 for other industries, and protection against ingress of water. The instrument can measure wall thickness, and detect near-face corroded surfaces, to a minimum of 0.8 mm on flat surfaces and down to 2 mm on curved surfaces with a minimum radius of 10 mm. A 5 mm steel reference standard is built into the case for zero correction and calibration. Power consumption is 0.6 W, giving 5 h continuous use from a fully charged battery pack. Power saving is achieved by an automatic circuit which switches the unit off after 3--4 rain if no readings are taken. Carrying weight of the pack, including rechargeable battery, is 0.915 kg. Three probes, versions of conventional probes but also modified for use in explosive environments, are available: DA212-Ex (10 MHz, measuring range 0.8 to 25 mm); DA 201-Ex (5 MHz, range 1.2 to 200 mm); DA203-Ex (2 MHz, range 5 to 300 ram).
Froude Consine's dynamic engine timing unit linked to a diesel engine
NDT INTERNATIONAL. DECEMBER 1983
Wells-Krautkramer Ltd, Blackhorse Road, Letchworth, Herts SG6 I HF, UK
351
probe. Ultrasonic pulses are emitted at a fixed angular interval of crank rotation such as to map at O.1° intervals. To compensate for fluctuations in engine speed the unit operates in conjunction with an angular reference such as flywheel teeth or a shaft encoder. To determine the fuel injection point, the discrete sonic frequency emitted as this occurs is detected by an acoustic microphone mounted a few millimetres from the injector. For spark ignition engines, a transducer is placed around one of the high-tension electrical leads. Froude Consine has spent three years and £250 000 developing the system. As well as eliminating the need for intrusive, potentially damaging, timing operations, the company says the system produces repeatable results with an accuracy within that of mechanical measurements. Four areas of application in particular are forseen: production engine timing; REtD; automated timing measurement, by interfacing to computerized data acquisition and control systems; and in-service maintenance, for which a simplified system will be available.
Froude Consine Ltd, Gregory's Bank, Worcester WR3 8AD, UK
Built into • cast aluminium housing, the D M 2 Ex ultrasonic thickness gauge
Ultrasonic thickness meter is explosion-proof An ultrasonic thickness meter that can be operated safely in explosive environments and is spray waterproof has been introduced by Wells-Krautkramer. Designated DM2-Ex, the instrument is a version of the pocket-size DM2 wall thickness meter and opens up new areas, such as mines, to ultrasonic measurement and corrosion detection. A lightweight cast aluminium housing provides detonation protection to VDE 0170:(Sch) s.i. for mines and to VDE 0171 :(Ex) s.i. G1-G5 for other industries, and protection against ingress of water. The instrument can measure wall thickness, and detect near-face corroded surfaces, to a minimum of 0.8 mm on flat surfaces and down to 2 mm on curved surfaces with a minimum radius of 10 mm. A 5 mm steel reference standard is built into the case for zero correction and calibration. Power consumption is 0.6 W, giving 5 h continuous use from a fully charged battery pack. Power saving is achieved by an automatic circuit which switches the unit off after 3--4 rain if no readings are taken. Carrying weight of the pack, including rechargeable battery, is 0.915 kg. Three probes, versions of conventional probes but also modified for use in explosive environments, are available: DA212-Ex (10 MHz, measuring range 0.8 to 25 mm); DA 201-Ex (5 MHz, range 1.2 to 200 mm); DA203-Ex (2 MHz, range 5 to 300 ram).
Froude Consine's dynamic engine timing unit linked to a diesel engine
NDT INTERNATIONAL. DECEMBER 1983
Wells-Krautkramer Ltd, Blackhorse Road, Letchworth, Herts SG6 I HF, UK
351