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. 04, 2012
Filed:
Apr. 24, 2009
Ponna PA, Bear, DE (US);
Ponna Pa, Bear, DE (US);
Agilent Technologies, Inc., Santa Clara, CA (US);
Abstract
A plunger for a syringe used to inject gas and liquid chromatography samples has an end portion surrounded by a flexible sleeve. The sleeve forms a seal in the bore of a barrel traversed by the plunger, the bore being in fluid communication with a cannula attached to the end of the barrel. The plunger has an end surface that is exposed and is flush with an annular end surface of the sleeve. The plunger end surface, and not the sleeve, contacts the cannula upon injection and avoids imposing cyclical hoop stresses on the barrel which tend to crack the barrel after a finite number of cycles. In a further embodiment, a thin layer of sleeve material covers the end surface of the plunger. The thin layer avoids inducing significant barrel stress.