RF Admittance apparatus and method for monitoring the contents of a pipe

Claim 1

A probe responsive to the degree to which the pipe is filled with a dielectric or conductive material and adapted for mounting between a pair of sections of the pipe and passing said material therethrough between said pair of pipe sections comprising: tubular conductive probe measuring electrode means having a hollow interior adapted for forming part of a material passageway through said probe between said pipe sections; a first pair of tubular solid insulation means each axially displaced from said probe measuring electrode means on either side of said probe measuring electrode means for electrically insulating said either side of the probe measuring electrode means and having a hollow interior adapted for forming part of the material passageway through the probe between said pipe sections; a pair of tubular conductive guard electrode means each outwardly axially displaced from said probe measuring electrode means on either side of said probe measuring electrode means separated from said probe measuring electrode means by one of said pair of first solid insulation means and having a hollow interior adapted for exposure to said material of said pipe and for forming part of said material passageway through said probe; a pair of tubular conductive ground electrode means adapted for grounding and each outwardly axially displaced from said probe measuring electrode means on either side of said probe measuring electrode means between one of said pair of guard electrode means and a section of pipe proximal the one guard electrode means; a second pair of tubular solid insulation means each outwardly axially displaced from said probe measuring electrode means on either side of said probe measuring electrode means between one of said pair of guard electrode means and a section of pipe proximal the one guard electrode means and within one of said pair of ground electrode means and adapted for electrically insulating said pair of ground electrode means from said pair of guard electrode means and said material and further having a hollow interior adapted for forming part of said material passageway. first conductor means having a first end coupled to said probe measuring electrode means and a second end adapted for supplying an AC measuring potential to said probe measuring electrode means; second conductor means having a first end coupled to at least one of said pair of guard electrode means and a second end adapted for suppying a separate AC guard potential to said guard electrode means; and capacitance means in series with said first conductor means, said probe measuring electrode means and said material in said probe and having an admittance which is large compared to the admittance of the probe measuring electrode means expected when said probe is filled with an insulating material of relatively low dielectric constant, and small when compared to said admittance expected when said probe is filled with conductive material of high conductivity.

Claim 6

A system for measuring the degree to which a pipe is filled with fluid comprising: tubular conductive probe measuring electrode means located between sections of said pipe and having a hollow interior adapted for passing said fluid between said pipe sections; a first pair of tubular solid insulation means each axially displaced from said probe measuring electrode means on either side of said probe measuring electrode means adapted for insulating said either side of said probe measuring electrode means and having a hollow interior adapted for passing said fluid betwen said sections and through said probe measuring electrode means; a pair of electrically coupled tubular conductive guard electrode means each outwardly axially displaced on either side of said probe measuring electrode means separated from said probe measuring electrode means by a different one of said first pair of solid insulation means and having a hollow interior exposed to the contents of said pipe and adpated for passing said fluid therethrough between said pipe sections and through said first pair of solid insulation means and said measuring electrode means; a pair of conductive ground electrode means each outwardly axially displaced on either side of said probe measuring electrode means between a different one of said pair of guard electrode means and one of said pipe sections proximal the one guard electrode means; a second pair of solid insulation means each axially outwardly displaced on either side of said probe measuring electrode means between a different one of said pair of guard electrode means and the one pipe section proximal said one guard electrode means and extending through a different one of said pair of ground electrode means and adapted for insulating said pair of ground electrode means from said pair of guard electrode means and said fluid, and having a hollow interior adapted for passing said fluid therethrough between said pipe sections and through said pair of guard electrode means, said first pair of insulation means and said measuring electrode means; first conductor means adapted to supply a source of AC measuring potential to said probe measuring electrode means; second conductor means adapted to supply a source of AC guard potential to said pair of guard electrode means substantially equal to said AC measuring potential; a source of AC measuring potential connected to said first conductor means; and a source of said AC guard potential connected to said second conductor means and adapted to maintain the potential of said pair of guard electrode means substantially at said AC measuring potential.

Claim 7

A system for measuring the degree to which a pipe is filled with fluid comprising: tubular conductive probe measuring electrode means located between sections of said pipe and having a hollow interior adapted for passing said fluid between said pipe sections; a first pair of tubular solid insulation means each axially displaced from said probe measuring electrode means on either side of said probe measuring electrode means adapted for insulating said either side of said probe measuring electrode means and having a hollow interior adapted for passing said fluid betwen said sections and through said probe measuring electrode means; a pair of electrically coupled tubular conductive guard electrode means each outwardly axially displaced on either side of said probe measuring electrode means separated from said probe measuring electrode means by a different one of said first pair of solid insulation means and having a hollow interior exposed to the contents of said pipe and adpated for passing said fluid therethrough between said pipe sections and through said first pair of solid insulation means and said measuring electrode means; a pair of conductive ground electrode means each outwardly axially displaced on either side of said probe measuring electrode means between a different one of said pair of guard electrode means and one of said pipe sections proximal the one guard electrode means; a second pair of solid insulation means each axially outwardly displaced on either side of said probe measuring electrode means between a different one of said pair of guard electrode means and the one pipe section proximal said one guard electrode means and extending through a different one of said pair of ground electrode means and adapted for insulating said pair of ground electrode means from said pair of guard electrode means and said fluid, and having a hollow interior adapted for passing said fluid therethrough between said pipe sections and through said pair of guard electrode means, said first pair of insulation means and said measuring electrode means; first conductor means adapted to supply a source of AC measuring potential to said probe measuring electrode means; second conductor means adapted to supply a source of AC guard potential to said pair of guard electrode means substantially equal to said AC measuring potential; a source of AC measuring potential connected to said first conductor means; and a source of said AC guard potential connected to said second conductor means and adapted to maintain the potential of said pair of guard electrode means substantially at said AC measuring potential.