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. 31, 2017
Filed:
May. 23, 2013
Air Products and Chemicals, Inc., Allentown, PA (US);
Neil Alexander Downie, Hampshire, GB;
Air Products and Chemicals, Inc., Allentown, PA (US);
Abstract
There is provided a method of automatically controlling the mass flow rate of a gas through an orifice through which, in use, choked flow is arranged to occur. The method uses an electronic valve located downstream of a gas source, a piezoelectric oscillator in contact with the gas upstream of the orifice and downstream of the electronic valve and a temperature sensor. The method comprises: a) driving the piezoelectric crystal oscillator at a resonant frequency b) measuring the resonant frequency of the piezoelectric oscillator c) measuring the temperature of the gas; and d) controlling the electronic valve in response to the resonant frequency of the piezoelectric oscillator and the temperature of the gas in order to regulate the mass flow rate of gas through said orifice.