A method and apparatus for precisely evaluating the lubricity characteristics of various oils and greases while they are under load and in motion and subject to variations in temperature.

Glass containers coated with a transparent polymer film, co-mingled with similar but non-coated containers, are identified without contact as they are moving on a conveyor. An optical position sensor triggers a stroboscope to emit a pulse of light that is directed to pass through the container. A light receptor essentially receives only that strobe light which has passed through the center of the container; light passing tangentially through the side of the container is blocked from the receptor. The light is filtered so that the receptor receives substantially only light in a wavelength range which will be attenuated by the polymer coating. Circuitry discriminates between the greater intensity of received light which has passed through an uncoated container and the lesser intensity of light through a coated container. Containers of the one type may be segregated from those of the other type by reject or sorting apparatus.

A single blade proximity probe uses fiber optics to direct a laser output at turbine engine blades and to return the reflected light to an image intensifier probe which provides an output indicative of blade clearance. To enable the system to measure the clearance of a single blade tip on an operating turbine, a second light beam having a different wavelength from the laser output is directed over the laser light path to count the blades and to strobe the laser on the desired blade.

The specification describes an interference optical measuring or sensing device, comprising a light source, a beam splitter, two component light paths and a radiation sensor for a multiple hole centrifuge rotor. When the rotor is in motion sample cells and the counter-weight move successively through the component light paths and at a particular position have both light paths extending through them. There is furthermore an arrangement for producing a position signal indicating that a selected hole is in a certain position in which it has both component light paths extending through it. A control arrangement ensures that the measuring device is activated briefly in the predetermined position of the selected hole. The light source continuously supplies light between the periods of activation of the measuring device. The component beam paths are respectively coupled with a control light sensor at positions, which in terms of the direction of light from the light source lie behind the multiple hole rotor and the control light sensor produces a component beam output signal when the respective component beam path is completed by a hole in the rotor. The position signal and the two component beam path signals are supplied to a coincidence circuit, which activates the measuring or sensing device on the simultaneous arrival of all three signals.

A new method and electronic circuit are provided to prevent image creep in automated centrifuges. The method and circuitry automatically substract a fixed time delay, which is associated with the strobe detection and firing circuitry, from a longer variable time period, which is inversely proportional to the rotational speed of the centrifuge, to thereby delay the flash of the strobe by a time inversely proportional to centrifuge rotation speed.