Great Lakes Instruments, Inc.

Gli International

Karl L King

Bruce W Weiss

Joseph A Millhouse

Robert W Endl

A sensor for measuring pH of a solution includes a housing with an exterior surface for exposure to the solution. A measuring glass electrode within a tubular circuit ground electrode extends through the exterior surface. A reference glass electrode is received in a neutral pH solution in the housing and is coupled by a salt bridge to the exterior surface. An electric circuit within the housing has a first preamplifier connected by a first conductor to the measuring glass electrode and has a second preamplifier connected by a second conductor to the reference glass electrode. The first and second conductors have substantially equal lengths so that ambient electrical noise equally affects signals from the electrodes. The electrical cable that carries output signals from the electric circuit passes through a ferrite sleeve which inhibits high frequency electric noise that is induced in the cable from reaching the electric circuit.

PH sensor with electrical noise immunity

A turbidimeter includes a housing having a cavity with an inlet through which a fluid flows. Two emitters are alternately driven by an alternating signal having a given frequency to transmit modulated light beams through the fluid. Two detectors produce signals representing the intensity of scattered and unscattered light within the fluid. Each of these detector signals is processed to measure the level of the signal component at the given frequency. Such processing includes filtering and phase demodulataing the detector signals to produce a signal indicative of the levels of the component signals at the given frequency. The turbidity is calculated from the signal levels measured as each emitter is excited.

Turbidimeter signal processing circuit using alternating light sources

A turbidimeter includes a housing having a cavity with an inlet through which the fluid enters the bottom of the cavity, and an outlet through which the fluid exits the top of the cavity. A removable baffle assembly is located within the cavity between the inlet and outlet. The baffle assembly is formed by three vertical plates spaced from each other and extending across substantially the entire cross sectional area of the cavity. The first plate defines a first passage near the top of the cavity through which all the fluid entering the cavity must flow. The second and third walls define a second passage near the top of the cavity through which gas bubbles entrained in the fluid travels to the outlet. A third passage is defined between the first wall and the outlet and a mechanism is provided for measuring the turbidity of the fluid flowing through the third passage. A calibration device formed by a block of glass ceramic material is insertable in the third passage to simulate a known turbidity fluid.

Growing community of inventors

Brown Deer, WI, United States of America

Karl L King