Seal for an instrument probe assembly

Abstract

There is disclosed an instrument probe assembly having a positive seal to prevent invasion of process fluids into the cavity of the assembly body. The instrument probe assembly comprises an elongated probe member which projects from a through passageway of the assembly body. The latter has attachment menas, typically pipe threads, at one end to permit it to be seated in an aperture of a process vessel, typically a pressure vessel. The elongated probe which projects from the assembly body into the vessel is commonly used as a capacitance sensing probe to determine the level of liquids or granular solids within the vessel. The probe assembly of this invention includes a sleeve projection from the inboard face of the assembly body, surrounding the projecting elongated probe member and a laminated sleeve formed of an inner sleeve of thermoplastic resin and an outer sleeve of heat shrinkable plastic which overlies the annular joint between the assembly body sleeve and the probe member and which is thermally applied, effectively sealing this annular joint against invasion of process fluids into the assembly body.

Dependencies are inferred from the claim text.