Precious metal testing apparatus with calibration system

摘要

A digital precious metal testing apparatus utilizes a probe that generates a galvanic voltage when an electrical circuit is completed with the object being tested being placed between the probe and the meter test pad formed of a copper pour with a gold coating. A microprocessor signals the percentage of precious metal through an indicator bar of LEDs. A calibration system is provided to enhance the accuracy of the testing apparatus by comparing a test reading from a known test specimen with a corresponding theoretical reading for that specimen. The calibration procedure establishes a recalibration curve from the test reading against which all subsequent readings will be compared to determine the content of precious metal. Calibration of the testing apparatus is initiated with the depression of a calibration switch and is undertaken with each power-up of the meter, with each probe replacement and with any substantial change in environmental conditions.

主权项

1. A testing apparatus for determining the content of precious metal within an object being tested, comprising:
a meter including:
a microprocessor having look-up tables stored therein;an indicator bar operably coupled to said microprocessor;a source of electrical power connected to said microprocessor;a test pad formed as a copper pour with a gold coating thereon; andan electronic circuit interconnecting said microprocessor, said indicator bar, said source of electrical power and said test pad; a probe connected to said meter and including:
a casing;a reservoir mounted within said casing and containing a supply of electrolyte;a fiber tip supported in said casing and having a first end coupled to said reservoir to receive electrolyte therefrom and a second end exposed from said casing;an electrical connector interconnecting said pen probe and said metering device; anda galvanic reaction apparatus mounted within said reservoir and having a first member connected to said fiber tip and a second member connected to said electrical connector, said galvanic reaction apparatus generating a galvanic voltage when said fiber tip completes an electrical circuit with said test pad; and a calibration system operably associated with said microprocessor to operate a calibration procedure that utilizes a calibration test reading from an application of said fiber tip of said probe to a known test specimen and compares said calibration test reading with a theoretical test reading stored in said look-up tables where said theoretical test reading corresponds to said known test specimen, said calibration procedure developing a calibrated response curve by applying an algorithm corresponding to the theoretical test reading in comparison to said calibration test reading so that all subsequent test readings will be adjusted to said calibrated response curve, said calibrated response curve comprising a response curve for said known test specimen from the look-up tables adjusted by the difference between said calibration test reading and said theoretical test reading, said calibrated response curve being used for all subsequent test readings for said probe until said calibration system is subsequently operated to create a new calibrated response curve.