Abstract: A gas-holding sludge digester is disclosed having a sideskirt which telescopes in a liquid chamber which is separate from a main digester tank and wherein the ballast is structured to increase gas pressure of the gas contained within the cover as the sideskirt telescopes upward.

Abstract: A point liquid level monitoring system includes a sensor removeably mounted to a liquid level device. The sensor is designed to direct a microwave signal from a transmitter through a window in the liquid level device. In one embodiment, the microwave signal is reflected off a surface in the device opposite the window and collected by a receiver. In another embodiment, the microwave signal is collected by a receiver mounted onto a second window opposite the first window through which the microwave signal is transmitted. When liquid is present in the liquid level device at or above the level of the transmitter and receiver, the microwave signal is attenuated as it passes through the liquid. Sensor electronics compare the received signal to a predetermined threshold level and provide an output indicating the presence or absence of liquid at the transmitter/receiver level.

Abstract: A method for converting a value for the partial pressure of oxygen (pO.sub.2) in blood at a measurement temperature to a corresponding value at a reference temperature (37.degree. C.). A value for pO.sub.2 is determined by measurements made in a patient's blood stream using a phosphorescent compound that is sensitive to the concentration of oxygen. The phosphorescent compound is illuminated with a short pulse of light, causing it to produce a phosphorescent emission having a rate of decay that varies as the function of the partial pressure of oxygen in the blood surrounding the phosphorescent compound. A detector produces an electrical signal corresponding to the intensity of the phosphorescent emission, and the electrical signal is converted to a corresponding digital value for input to a microcomputer. Also supplied to the microcomputer in digital form is a signal indicative of the temperature at the measurement site where the phosphorescent compound is disposed.

Abstract: An articulated vehicle with steering linkage having a main chassis (2) pivotally connected and supported by a front sub-chassis (1) for pivotal movement about a vertical axis (27) and pivotally connected to a rear sub-chassis (6) about a vertical axis (30), the front sub-chassis having a median plane (1') and the rear sub-chassis having a median plane (6') a linkage member (71) mounted on the rear sub-chassis for movement along the median plane thereof (6), and a linkage member (72) mounted on the front sub-chassis for movement along the front median plane (1'), the linkage members being connected together by a pivot member (73) for relative pivotal movement about a vertical pivot axis (61) lying substantially at the intersection of the median planes of the front and rear sub-chassis during turning of the vehicle. A control link (82) is pivotally connected on the median plane (2') of the main chassis (2) and also pivotally connected to the linkage member (71) so that during turning the ratio of the angle (.

Abstract: A portable wheeled hand truck mounts a rotary actuator, powered by a hand or motor-operated pump also contained on the truck, for lifting and rotating a diffused aeration piping array from a liquid/slurry treatment tank into a working and servicing position adjacent to the tank, such as a walkway. The wheeled truck is hand maneuvered so that the powered end of the actuator is in alignment with a connection arm extending from a pivotable pipe which is part of the array. A multi-positionable handle is included on the hand truck which, in an essentially horizontal position, is temporarily fixed to a tank walkway surface to support the reaction forces incident to lifting and rotating the heavy mass of the piping array. When not so fixed, the handle may be moved to an essentially vertical position for storage and to an intermediate position to maneuver the truck into alignment with the piping array connector arm.

Abstract: A pair of generally L-shaped identical rod members having a cantilevered bottom end extending transversely from a horizontal base portion are assembled so that the cantilevered end of a first rod member can abut the horizontal base portion of a second rod member while the cantilevered end of the second rod member simultaneous abuts the horizontal base portion of the first rod member. The abutments of the two rods can be made along part or effectively all of the reach or length of the rod members base portions so that the vertical portions of the rod members have two or more different spans therebetween so as to accommodate a range of pipe diameters to be supported. The abutment of the respective cantilevered ends and the horizontal base portions of the rod members are either welded together or clamped securely at various spans forming a closed generally rectangular loop bounded by the respective cantilevered ends and base portions of the two rod members.

Abstract: The vehicle has a main chassis (2) pivotally supported by front and rear sub-chassis (1,6), one of which carries the engine. Constant velocity power is communicated between the two sub-chassis (1,6) by an intermediate shaft (20) connected to front and rear shafts (18,21) extending along the center-lines (1',6') of the respective sub-chassis (1,6). For steering, pivoting of the rear sub-chassis (6) is controlled in dependence of the pivoting of the front sub-chassis (1) so that, during, turning, the center-lines (1',6') of the sub-chassis intersect at a point (61) nearer to the pivot axis (27) of the front sub-chassis (1) than to the pivot axis (30) of the rear sub-chassis (6). The universal joints (20a,20b) of the intermediate shaft (20) are equidistant from the intersection point (61). The rear sub-chassis (6) thus pivots through a smaller angle than the front sub-chassis (1).

Abstract: A trailing unit is pivotally supported by a tractor or leading unit at the front and a sub-chassis at the rear. Pivoting of the sub-chassis is controlled in accordance with turning of the leading unit so that the angle between sub-chassis and trailing unit is equal and opposite to the angle between leading unit and trailing unit. Power is communicated between leading unit and sub-chassis by a front shaft on the leading unit, a rear shaft on the sub-chassis, and an intermediate shaft connected to them by universal joints at positions equidistant from the pivot axes of the leading unit and sub-chassis.

Abstract: A digestor includes a tank and an inverted dish-shaped cover, the lower end of which extends into sludge contained within the tank. The cover is ballasted by a number of ballast members which resemble tubs and which are integrally formed of concrete. Each ballast member is mounted with its cavity facing upwardly so that the ballast cavities automatically fill with sludge upon start-up of the digestor. When partially surfaced above the sludge, the predetermined total weight of sludge in the ballast members causes a substantial increase in the pressure exerted by the cover on the contained gas than would be exerted by the cover and unfilled ballast members.