Airco, Inc.

Autotrol Corporation

Michael G Busby

Donald R Janke

Wilfried R Peickert

Diane E Hartwig

Frank Kunesh

Errol E Polenske

Abraham H Kou

A water treatment apparatus has a tank that contains a resin bed through which water flows. The apparatus is controlled by occasionally measuring the conductivity of the resin bed at two spaced apart locations to produce first and second conductivity measurements. The ratio of the two conductivity measurements is calculated periodically. The present ratio value, along with the minimum and maximum ratio values that occurred since a previous regeneration of the resin bed, are used to determine the movement of an exhaustion front through the resin bed. A probability of exhaustion also is determined and when that probability exceeds a given value, regeneration of the resin bed is initiated. The conductivity measurements are used to determine if the resin bed has lost efficiency and in which event a warning signal is sent to the user. During regeneration, the conductivity at one of the locations in the resin bed is monitored to detect whether a regenerant has entered the tank; if not another warning signal is sent to the user.

Apparatus and method for controlling regeneration of a water treatment

An ultrasonic flowmeter which measures gas velocity including a pair of ultrasonic transducers oppositely located around a conduit at a predetermined angle to the flow direction. Each transducer alternates between acting as a transmitter and a detector of ultrasonic frequencies, thus as one transducer transmits, the other receives. A measurement is made of the time of flight of the ultrasonic signal between the transmitter transducer and the receiver transducer and a microcomputer calculates the velocity of the gas by a known mathematical relationship utilizing the difference between the time of flight of the ultrasonic signals traveling upstream and those traveling downstream. The time of flight is determined by the phase shift or difference in phase angle between the signal at the transmitter transducer and the signal detected by the receiver transducer. To prevent ambiguity arising when the phase angle difference exceeds 360.degree., the microcomputer periodically determines, by taking into account the differing gases and density thereof being measured, a zero flow phase by calculating an averaged value phase angle of the ultrasonic signals in both the upstream and downstream directions. When that average phase angle approaches a predetermined limit, the microcomputer shifts the phase reference to a new value, the effective overall phase shift can thus exceed 360.degree., but the microcomputer will still reflect that difference in phase angle and thus, the time of flight of the ultrasonic signals.

Ultrasonic flowmeter

A membrane and the method of making the same is disclosed for use with glucose analyzers to detect the level of glucose in liquid mediums such as whole blood. The membrane comprises a thin base wafer of a hydrophobic fluorocarbon material such as polytetrafluoroethylene (TEFLON). The wafer is initially etched by removing surface fluorides to produce a hydrophilic surface and is then contacted with a mixed reagent formed by combining in a volume ratio of about 1:1:1 about 4% paraformaldehyde in water, about 5% bovine serum albumin in water and about 10% glucose oxidase in water. The resultant membrane contains glucose oxidase covalently bonded to the surface of the base wafer.

Glucose analyzer membrane containing immobilized glucose oxidase

Growing community of inventors

Madison, WI, United States of America

Michael G Busby