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. 03, 1978
Filed:
Dec. 12, 1977
David R Friswell, Holliston, MA (US);
Burleigh M Hutchins, North Attleboro, MA (US);
Other;
Abstract
The bubble sensor is embodied in a liquid chromatographic system. In the exemplified system a sample conduit or loop which is already filled with liquid eluent communicates with the bore of a needle. The opening of the needle bore is immersed in a liquid sample so that the sample may be backfilled into the sample loop by the withdrawal of the syringe which communicates with the sample loop. After the liquid sample has been drawn into the sample conduit, the needle is lifted from the sample source and moved toward a final position in which the sample conduit will be placed in parallel with a primary conduit, so that the pump which pumps the liquid eluent will drive the sample from the opening toward the chromatrographic column. As the needle is being raised toward this position, it is stopped at an intermediate position in which the orifice is sealed. In this condition, the liquid sample is within the sample conduit which is part of a closed space between the orifice and the syringe. The syringe is now driven a small distance to reduce the volume of that space by a predetermined, programmed increment. The pressure before and after the change in the space may be compared to indicate the presence or absence of a bubble in the sample. A preferred way of proceeding is to determine the number of incremental changes of predetermined volume to bring the change in pressure up to a predetermined point, for example, 30 psig. If the number of such incremental changes is less than a predetermined number, then it may be presumed that the sample is free of bubble. If the number is greater than the predetermined number, a possible bubble inclusion is indicated and further action may be taken as more fully described hereinafter.