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:
Nov. 20, 1990
Filed:
May. 31, 1989
Gerald J Dunstan, Wheathampstead, GB;
Ian D Gilbert, St. Albans, GB;
Coulter Electronics, Inc., Hialeah, FL (US);
Abstract
A particle counter, of the type utilizing a Coulter(R) type aperature and a suction flow path downstream from the aperture, has a pair of electrodes on both sides of the aperture. A current is provided from the downstream electrode to the upstream electrode and pulses in the resulting voltage across the aperture are monitored to detect the passage of blood cells through the aperture. A grounded electrode is placed in the downstream flow path at a position near the package panel to isolate the cell counter from external electrical noise signals. An isolated high input inpedance amplifier is coupled to provide the monitored voltage to an inserted electrode positioned between the downstream aperture electrode and the grounded panel electrode. Because the inserted electrode and downstream electrode are then at the same voltage, no current flows through that portion of the flow path.