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:
Dec. 21, 2010
Filed:
Jan. 24, 2007
Harold Robert Schnetzka, York, PA (US);
E. Curtis Eichelberger, Jr., Harrisburg, PA (US);
Paul Nemit, Jr., Roanoke, VA (US);
Harold Robert Schnetzka, York, PA (US);
E. Curtis Eichelberger, Jr., Harrisburg, PA (US);
Paul Nemit, Jr., Roanoke, VA (US);
Johnson Controls Technology Company, Holland, MI (US);
Abstract
A system for cancelling or attenuating noise in at least two positive displacement compressors proximately located from each other for use with a heating or cooling system. A lead compressor and a lag compressor have a controllable rotational speed and phase of operation. A controller selectably controls the rotational speed and the phase of operation of each of the compressors. The controller controls the rotational speed of the compressors at substantially the same speed for each compressor, with a phase-lock loop and a comparator circuit for each compressor. The controller controls the phase of operation of the compressors through an oscillator so that the lead and lag compressor pressure pulses are spaced between successive outlet pressure pulses to effectively double the combined pulsation frequency for noise attenuation.