Abstract: A system for programming and controlling the rate at which an agricultural chemcial (e.g., fertilizer) is supplied to the water in an agricultural irrigation system. In one embodiment the system is combined with a center pivot irrigation system having a vertical water feed pipe, a horizontal boom, and a chemical supply connected to the feed pipe. A rotation sensor determines the degree of rotation of the boom and a controller controls the amount of chemical supplied to the feed pipe. The system enables the amount of chemical applied to be varied from one section of a field to another.

Abstract: A system for programming and controlling the rate at which an agricultural chemical (e.g. fertilizer) is supplied to the water in an agricultural irrigation system. In one embodiment the system is combined with a center pivot irrigation system having a vertical water feed pipe, a horizontal boom, and a chemical supply connected to the feed pipe. A rotation sensor determines the degree of rotation of the boom and a controller controls the amount of chemical supplied to the feed pipe. The system enables the amount of chemical applied to be varied from one section of a field to another.

Abstract: A system and method for quantitative analysis of a solution to determine the concentration of a chemical species in the solution. The system includes a reaction vessel; a source of at least one liquid reagent for reacting with the chemical species being tested for; a conduit leading from the reagent source to the reaction vessel; pneumatic pressure for forcing the reagent through the conduit; controls for controlling the amount of reagent added to the reaction vessel; and a detection device for detecting reaction between the reagent and the chemical species.

Abstract: An improved process for quantitatively determining nitrogen content or other elemental content in a wide variety of materials. The process avoids the use of conventional catalysts, is simpler and faster than previous techniques, and results in a very high degree of accuracy. The process involves the use of a hydrogen peroxide which is added to the digest continuously, while the digest is boiling, while refluxing with a fractionating column. The digestion process also enables quantitative determination of various elements other than nitrogen.

Abstract: An improved process for quantitatively determining nitrogen content in a wide variety of materials. The process avoids the use of conventional catalysts, is simpler and faster than previous techniques, and results in a very high degree of accuracy. The process involves the use of a reagent solution prepared by mixing hydrogen peroxide and concentrated sulfuric acid. The digestion process also enables quantitative determination of various elements other than nitrogen.

Abstract: A glass pH measuring electrode is mounted in a piston that reciprocates in a chamber which is in fluid communication with a reference electrode. Intake and outlet lines to the chamber are controlled by valves. A drive means operates the piston and the valves to pull successive liquid samples into the chamber for measurement and then to discharge them. The drive means also controls two positive displacement pumps, one of which feeds controlled amounts of electrolyte past the reference electrode and the other feeds a bacterial sterilizing agent to the chamber. The electrolyte flow past the reference electrode and into the discharge flow from the chamber maintains open electrical communication with the chamber. A deformable body, preferably a bed of finely ground methyl methacrylate grit, in the chamber engages and cleans the glass electrode as the piston reciprocates.

Abstract: A conductivity probe having a cylindrical body with an annular open-sided groove in which the electrodes are disposed, and a sliding cover wall for the groove biased to a position covering the groove but easily operable with one hand to slide the cover so as to open the groove. Viscous or slurried material can easily enter the groove, be trapped and confined for the conductivity measurement and then readily washed from the groove and surrounding parts for the next operation.

Abstract: A pipet for slurry and the like comprising a body with an end chamber containing a slidable element which, between them, defines a predetermined volume. The element includes an end plate to close the chamber, and a biased plunger is mounted in the body for moving the element so as to open and close the chamber and thus trap the predetermined volume of material to be sampled. The element is replaceable with one of different size to vary the volume of sample. In one form, a cutting edge on the body and a cutting surface on the end plate cooperate to sever fibrous material only partly in the chamber.

Abstract: A mechanical strainer having a stack of alternate discs and blades biased together, the discs being slowly driven by a motor and the blades being anchored on the strainer frame, which discs and blades are perforated so that water surrounding the strainer can leak into the perforations of the stack. A passage is formed in the frame communicating with the perforations of the stack, and a tube leading to where the water is desired is coupled to the frame passage. The result is a kind of labyrinth rotary seal having intended leakage.

Abstract: A liquid dispensing device for chemical titration having a reciprocating plunger for expelling fluid from an attached titrating solution cartridge, and a lead screw for reciprocating the plunger whose rotation is measured and displayed by a digital rotation counter. The plunger can be selectively uncoupled from the lead screw to permit direct plunger positioning. A pair of manual knobs allow rapid direct rotation of the lead screw or slower, geared down rotation of the screw.

Abstract: A portion of a colorimetric liquid analyzer including a glass tube cell, a plunger mounted for reciprocation in the cell and having a passage to the cell, and a long liquid sample supply tube running from a body of liquid to be tested to the plunger passage. A "T" connector is provided in the tube and a pair of on-off valves which, together with the plunger, act to pump fixed volumes of fluid into and out of the cell. Means are provided to pump substantial air bubbles into the tube near its intake end, and the air bubbles are separated from the liquid through a vertical section of the T-connector so that only liquid is pumped into the cell. Preferably, acid is also added to the tube at its intake end to help dissolve particulate matter while the air bubbles continuously sweep the tube clean.

Abstract: An analytical method for determining the elemental carbon and nitrogen contents of a sample. The sample, as a liquid or in finely divided solid form is placed in an evacuable pressure vessel and is then oxidized with a cupric oxide oxidizing agent to convert carbon to CO.sub.2, nitrogen to N.sub.2, and hydrogen to water. After cooling to condense the water, the resulting pressure provides a measure of the total carbon plus nitrogen content of the original sample. An aliquot of the gas is then treated for CO.sub.2 removal, and the resulting change in volume thereby provides a measure of the ratio of carbon to nitrogen in the original sample.

Abstract: A method of colorimetrically analyzing even heavily turbid or already strongly colored water by first sensing transmitted light from a light beam through a sample of the fluid, adding color-producing test reagents to the sample, again sensing transmitted light from an identical light beam, and comparing the sensed light readings to detect the change, if any, produced by the added reagents. Two colorimetric cells are used, one for testing before the addition of reagents and the other after, with the cells being defined by glass cylinders in which pistons reciprocate to pump measured samples to the cylinders, clean the cylinders on each pumping stroke, and "valve" or block the light beam so that the other cylinder can be "read". Simple displacement pumps for the reagents, and the cell pistons, cooperate with valves defined by pincher arms squeezing flexible tubing to move measured amounts of sample and reagent throughout the analyzer.