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:
Mar. 09, 1993
Filed:
Aug. 23, 1991
George H Fellingham, San Jose, CA (US);
Lance B Koll, Santa Clara, CA (US);
Timothy J Hughes, Palo Alto, CA (US);
Abbott Laboratories, Abbott Park, IL (US);
Abstract
An ultrasonic detector for detecting air in a fluid passage is disclosed. The detector comprises a transmitting crystal and complementary receiving crystal disposed around the fluid passage. A sweep oscillator is used to apply a variable-frequency signal to drive the transmitting crystal into resonance so that a burst of ultrasonic energy is released therefrom. The swept frequency range encompasses the resonant frequency of the transmitting crystal, ensuring that it resonates. If there is fluid in the passage, the ultrasonic energy causes a relatively high voltage to develop across the receiving crystal. Air in the passage attenuates transmission of the ultrasonic energy so that a low voltage signal is developed across the receiving crystal. A sensor circuit connected to the receiving crystal monitors the signal developed thereacross and in response to the magnitude of the signal, asserts a signal that indicates whether there is air or fluid in the passage.