Patent ID: 6670608
Filing Date: 2003-12-30
Classification: H01J

Abstract:
A system for transferring a sample of process gas from a supply thereof at a pressure P1 to an inlet of a remotely located mass spectrometer maintained at a pressure P2 by a pump having a pumping speed Q, comprising: a capillary conduit having a predetermined capillary length and capillary diameter, said capillary conduit in communication with the supply of process gas and the inlet of the spectrometer; and a flexible protective conduit surrounding said capillary conduit; said capillary length and said capillary diameter being related as wherein len is said capillary length in inches, D is said capillary diameter in inches, len=(&AutoRightMatch;&it;1&it;,&it;520&CenterDot;len&CenterDot;in3&CenterDot;torr-1&CenterDot;sec-1&it;&AutoLeftMatch;)&it;(D)4&it;(P12-P22)QP2P1 is the pressure in torr of the process gas at the supply thereof, P2 is the pressure in torr maintained in the mass spectrometer, and Q is the pumping speed in liters per second.