Patent ID: 9217659
Filing Date: 2015-12-22
Classification: G01F

Abstract:
1. A probe defining a transmission line for use with a measurement instrument including a pulse circuit connected to the probe for generating pulses on the transmission line and receiving reflected pulses on the transmission line, the probe comprising: a conductive outer sleeve for mounting to a process vessel; a center conductor coaxial with the outer sleeve for conducting the pulses; a primary seal element between the outer sleeve and the center conductor spaced a select distance from a near end of the outer sleeve; a secondary seal element between the outer sleeve and the center conductor spaced proximate the near end of the outer sleeve, to define a generally tubular space between the primary seal element and the secondary seal element; a dielectric insert filling a portion of the tubular space proximate the secondary seal element; and a leak detection tube in the tubular space between the dielectric insert and the primary seal element, the leak detection tube having an inner diameter greater than an outer diameter of the center conductor to define a void, wherein the dielectric insert and the leak detection tube provide a substantially continuous uniform impedance under dry conditions.