Blood leak detector suitable for use with artificial kidneys
First Claim
1. Blood leak detector which comprises:
- a tubular measurement cell having at least a central part thereof which is transparent and having an inlet at one end thereof for a dialysis solution under test and an outlet at the other end thereof;
light-emitting means for irradiating said measurement cell, comprising a first light-emitting element emitting mainly at wavelengths of 500-600 nm at which blood pigment absorbs light and a second light-emitting element emitting mainly at longer wavelengths than said first light-emitting element at wavelengths of 600 to 750 nm;
photo detecting means for receiving the light transmitted through said measurement cell;
means for alternately driving said first light-emitting element and the second light-emitting element and,means for discriminating among output signals of said photo detecting means, said driving means supplying a reference signal to said discriminating means for enabling thereof to discriminate between a first state wherein the amount of the transmitted light of said first light-emitting element is in equilibrium with that of said second light-emitting element, and a second state wherein the amount of the transmitted light of said first light-emitting element is smaller than that of said second light-emitting element.
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Abstract
A high sensitive and stable blood leak detector suitable for use with artificial kidneys. The detector has an optical portion comprising a measurement cell through which dialysis solution under test passes, an alternately energized pair of light-emitting diodes positioned on one side of the cell, and a photo sensitive detector positioned at the opposite side of the cell and close thereto. One light-emitting diode emits radiation at longer wavelengths, and the other at shorter wavelengths. Both the diodes are adjusted to produce photo detecting signals at the same level when no blood exists in the cell. The photo detecting signals at the photosensitive detector are detected and analyzed to give signals deflected in one direction in proportion to the degree of blood leak when it has occurred. When bubbles are detected, they give signals in the opposite direction, based on the fact that blood absorbs light mainly at shorter wavelengths while bubbles scatter light mainly at longer wavelengths.
165 Citations
11 Claims
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1. Blood leak detector which comprises:
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a tubular measurement cell having at least a central part thereof which is transparent and having an inlet at one end thereof for a dialysis solution under test and an outlet at the other end thereof; light-emitting means for irradiating said measurement cell, comprising a first light-emitting element emitting mainly at wavelengths of 500-600 nm at which blood pigment absorbs light and a second light-emitting element emitting mainly at longer wavelengths than said first light-emitting element at wavelengths of 600 to 750 nm; photo detecting means for receiving the light transmitted through said measurement cell; means for alternately driving said first light-emitting element and the second light-emitting element and, means for discriminating among output signals of said photo detecting means, said driving means supplying a reference signal to said discriminating means for enabling thereof to discriminate between a first state wherein the amount of the transmitted light of said first light-emitting element is in equilibrium with that of said second light-emitting element, and a second state wherein the amount of the transmitted light of said first light-emitting element is smaller than that of said second light-emitting element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Blood leak detector which comprises:
- a transparent measurement cell through which dialysis solution under test flows;
composite light-emitting diodes irradiating the measurement cell and having a first light-emitting diode which emits in the range of 520-600 nm and a second light-emitting diode which emits in the range of 600-750 nm;
a photo detecting element to receive the light from the light emitting diodes transmitted through the measurement cell;
means for driving the first light-emitting diode and the second light-emitting diode alternatively after a reference square wave signal;
means for adjusting the balance between an output signal of a photo detecting element due to the first light-emitting diode and an output signal of the photo detecting element due to the second light-emitting diode in the normal state in which no blood leak exists; and
means for detecting deflection from the normal state resulting from change either of the output signal of the photo detecting element due to the first light-emitting diode or of the output signal of the photodetecting element due to the second light-emitting diode. - View Dependent Claims (10, 11)
- a transparent measurement cell through which dialysis solution under test flows;
Specification