Coulter Electronics, Inc.

Watsco, Inc.

Ernesto Bello

Guenter Ginsberg

John A Richardson

Bruce J Hodgins

Vladimir J Drbal

Ivan K Saltz

Richard M Grimm

Ted W Britton

Rodolfo R Rodriguez

Wallace H Coulter

Steven N Kolber

Joseph F Mibelli

Electronic circuitry senses over-voltage and under-voltage within narrow threshold limits, and voltage interruption, in the energization circuit of a sensitive load, such as a refrigeration compressor motor load, to protect against overheating damage and burn-out. Setting to a nominal operating line voltage is provided for to obviate readjustment to the threshold voltages of a window comparator utilized to sense over-voltage and under-voltage.

Electrical load protection device

A fluid transfer mechanism for rapidly and accurately picking up or aspirating a fluid quantity or aliquot in one position, moving it to a second position and dispensing the aspirated aliquot. The mechanism includes an arm mounted on a high helix shaft on one end and driven up and down the shaft by a first motor and rotated around the shaft by a second motor. The arm includes at a second end a fluid transfer probe which is moved into and out of the fluids to aspirate and dispense the fluids in precise angular locations. The arm may be accelerated and deaccelerated as it is rotated to avoid vibrations and spilling of the fluid from the probe. The probe may include a level sensing structure for sensing when the probe has contacted a fluid surface. The probe also may be coupled to an oscillator to oscillate the probe in a vessel into which the fluid has been dispensed to mix the fluids therein.

Fluid transfer mechanism

A level sensor of a fluid transfer mechanism for determining when the bottom tip of a fluid aspirating probe touches or contacts the top surface of a sample fluid. The level sensor senses the contact capacitively by grounding one plate of a capacitor through the sample fluid and fluid aspirating probe. One capacitor plate is formed of an electrode biased against the bottom of a rotatable supply tray and positioned under a sample containing cavity in the tray. The other capacitor plate is formed by the bottom surface of the sample fluid in the supply cavity, and the dielectric of the capacitor is formed of the supply tray material. An AC signal is applied to the electrode and the probe is grounded. The change in voltage occurring in the AC signal at the electrode when the probe touches the top surface of the sample fluid it is sensed to provide the touch signal.

Level sensor apparatus and method

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Miami Springs, FL, United States of America

Ernesto Bello