The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 19, 1976
Filed:
Apr. 29, 1974
Charles A Kirklen, Richardson, TX (US);
Charles F Rhodes, Jr, Richardson, TX (US);
Sun Oil Company (Delaware), Dallas, TX (US);
Abstract
The radio frequency resistance between a pair of conductive elements, for example, adjacent pipe sections of a pipeline, which are coupled together through an insulator, may be determined by contacting each pipe section with one of a pair of probes or electrodes connected across the output of a radio frequency oscillator which is coupled to the input of a rectifier and filter circuit. The probes are connected across the oscillator output through a resistor which insures that the direct current output of the rectifier is directly proportional to the RF resistance between the pipe sections. The output of the rectifier is coupled to a meter through an operational amplifier. The meter, which provides a direct readout of the resistance being measured, may be provided with a current limiting circuit which protects the meter from excessive DC current. Calibrating means may be provided to enable adjustment of the gain of the operational amplifier for resistance readings within several ranges.