Abstract: An improved level measuring system based upon capacitance to current conversion is provided with equipment for compensating for variations in dielectric constant in a measured liquid. A reference probe is located entirely within the liquid to be measured, but is sensitive to changes in dielectric constant. The measurement probe responds both to changes in dielectric constant and variations in liquid level. A differential output from the reference probe and the measurement probe effectuates compensation for variations in the dielectric constant in the material measured. A control unit at the output provides means for automatic calibration through a microprocessor.

Abstract: There is disclosed a capacitance probe for determining the level of high electrical resistance material in a vessel. The probe comprises at least two parallel, large surface area blades which are supported from a mounting plate and spaced apart to define a capacitance path. One blade is attached to an insulator body which is attached to the mounting plate while the other blade is directly attached to the mounting plate in electrical continuity therewith. The insulator body is a ceramic sleeve having a length sufficient to prevent shunting of the capacitance path. The probe is particularly intended for detection of level of fly ash and the like in a receiver vessel.

Abstract: There is disclosed a capacitance probe and sealing gland assembly of an improved construction which permits facile manufacture, applicable to a variety of capacitance probe rod diameters. The construction employs a continuously insulation-coated probe rod which is received in a gland housng and which has an intermediate portion having non-coincident sidewall surfaces mounted in an interior cavity of the gland housing to provide axial and rotational restraint of the probe rod. The assembly includes a sleeve received over the insulation-coated probe rod with a sidewall contour conforming to the non-coincident outer surfaces of the intermediate portion of the probe rod. The sleeve has distal flanges that are received against interior abutments of the gland housing to provide axial and rotational restraint. The ends of the sleeve also compress the annular packing seals of the assembly.

Abstract: There is disclosed a probe assembly suitable for mounting in a pressure vessel and the like which has an elongated probe member with a continuous and unbroken insulation coating that is received within an assembly body. The latter has attachment means to secure the body in an aperture of a pressure vessel. The elongated probe member has an outwardly deflecting radial bend, and reverse and straightening radial bends which are received within and bear against supporting shoulders in the assembly body. The probe has its elongated portions projecting from opposite ends of the body, substantially coaxially. The aforedescribed construction securely retains the probe member within the assembly body, preventing its forced dislodgement therefrom under the pressure within the pressure vessel or misalignment during installation or use while, nevertheless, providing a continuous unbroken electrical insulation, thereby insuring against malfunctions that can occur when process fluids leak into the assembly body.