Apparatus for measuring magnetic susceptibility

Claim 2

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnet circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with the magnetic fields in the gap, have zero resultant; the test bodies differing in interior content, so that the first test body in conjunction with a reference gas, and the second body in conjunction with a test material experiences additional, deflective forces in the gaps which act at Different magnitudes on the bodies with a non-zero resultant force for similar magnetic field strength in the gaps; compensating means including at least one stationary coil disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps, for unbalancing the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 3

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnet circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with the magnetic fields in the gap, have zero resultant; the test bodies differing in interior content, so that the first test body in conjunction with a reference gas, and the second body in conjunction with a test material experiences additional, deflective forces in the gaps which act at Different magnitudes on the bodies with a non-zero resultant force for similar magnetic field strength in the gaps; compensating means including at least one stationary coil disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps, for unbalancing the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 4

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnet circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with the magnetic fields in the gap, have zero resultant; the test bodies differing in interior content, so that the first test body in conjunction with a reference gas, and the second body in conjunction with a test material experiences additional, deflective forces in the gaps which act at Different magnitudes on the bodies with a non-zero resultant force for similar magnetic field strength in the gaps; compensating means including at least one stationary coil disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps, for unbalancing the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 5

In an instrument as in claim 1, wherein the magnetic circuits include adjustable electromagnetic means modifying the magnetic fields in the gaps in opposite directions to obtain correction and similar magnetic fields in the fields.

Claim 6

In an instrument as in claim 1, wherein the compensating means includes two stationary coils, including said one coil and one for each of said magnetic circuits, to provide oppositely effective compensating fields in the gaps to produce a composite force counteracting said non-zero resultant.

Claim 7

In an instrument as in claim 1, wherein the two magnetic circuits are a.c. energized, the dumbbell being suspended for undergoing oscillation, the pick-up means responsive to said oscillation.

Claim 8

In an instrument as in claim 1, the magnetic circuits being biased by permanent magnet means.

Claim 9

In an instrument as in claim 5, the magnetic circuits including at least one permanent magnet and magnetic conductive means leading to said gaps; the conductive means holding two coils, including the one coil, to obtain said unbalancing of the magnetic fields.

Claim 10

In an instrument as in claim 1, and including at least trimming coil with adjustible energization in at least one of said circuits to obtain the zero resultant in the absence of said additional deflective force.

Claim 11

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with the magnetic fields in the gaps, have zero resultant; the first and second gaps being penetrated by a test gas and surrounding said bodies, the first body being hollow and closed, and containing a reference gas, and displacing a larger volume of the test gas than the second body does, so that the test bodies experience additional deflective force in the gaps, the additional deflective force resulting from the different displacement volume of test gas as produced by the first and second bodies, there being a nonzero resultant deflecting force on the dumbbell for similar magnetic field strengths in the gaps accordingly; compensating means including at least one coil not being deflected with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means conneCted to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 12

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with the magnetic fields in the gaps, have zero resultant; the first and second gaps being penetrated by a test gas and surrounding said bodies, the first body being hollow and closed, and containing a reference gas, and displacing a larger volume of the test gas than the second body does, so that the test bodies experience additional deflective force in the gaps, the additional deflective force resulting from the different displacement volume of test gas as produced by the first and second bodies, there being a nonzero resultant deflecting force on the dumbbell for similar magnetic field strengths in the gaps accordingly; compensating means including at least one coil not being deflected with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means conneCted to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 13

An instrument as in claim 8, wherein the second body is smaller than the first body, so that the additional force is the result of the difference in displacement volume for test gas, as provided by the two bodies.

Claim 14

An instrument as in claim 8, wherein the second body is hollow and open to be penetrated by the gas.

Claim 15

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps, so that forces acting on them due to the solid material of the test bodies and due to interaction thereof with the magnetic fields in the gap, have zero resultant; the first and second gaps being penetrated by a gas surrounding the bodies, the first body only holding a material separated from the gas and of different susceptibility, so that the first and second bodies experience additional different deflective forces on account of said difference in susceptibility with a non-zero resultant force for similar magnetic field strengths in the gaps; compensating means including at least one coil not moving with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps to unblance the magnetic fields in the gaps for off-seeting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in respresentation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 16

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps, so that forces acting on them due to the solid material of the test bodies and due to interaction thereof with the magnetic fields in the gap, have zero resultant; the first and second gaps being penetrated by a gas surrounding the bodies, the first body only holding a material separated from the gas and of different susceptibility, so that the first and second bodies experience additional different deflective forces on account of said difference in susceptibility with a non-zero resultant force for similar magnetic field strengths in the gaps; compensating means including at least one coil not moving with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps to unblance the magnetic fields in the gaps for off-seeting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in respresentation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 17

An instrument as in claim 11, wherein the first body and the second body are similar open containers, the first body holding a sample, the gas being a reference gas.

Claim 18

An instrument as in claim 11, wherein the first body is a closed container holding a reference gas, the gas being a test gas.

Claim 19

In an instrument as in claim 11, wherein the two bodies have different volume for displacing different amounts of test gas, the mass and material of the test bodies being at least approximately similar so that the additional force is provided by the difference in magnetic interaction with the different displacement volume in the gaps.

Claim 20

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with similar magnetic fields in the gaps, have zero resultant; the first body being a container for a sample, the second body being without a sample, the test bodies being surrounded by a reference gas, so that a deflective non-zero resultant force acts on the dumbbell for similar fields in the gaps; compensating means disposed for acting on at least one of said magnetic circuits to provide for at least one magnetic compensating field, respectively in at least onE of said gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 21

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with similar magnetic fields in the gaps, have zero resultant; the first body being a container for a sample, the second body being without a sample, the test bodies being surrounded by a reference gas, so that a deflective non-zero resultant force acts on the dumbbell for similar fields in the gaps; compensating means disposed for acting on at least one of said magnetic circuits to provide for at least one magnetic compensating field, respectively in at least onE of said gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 22

In an instrument for measuring magnetic suceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but wihtout enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with similar magnetic fields in the gaps have zero resultant; the first body being an open container for receiving a test gas surrounding the dumbbell and penetrating the gaps and into the first body, the second body being a closed container holding a reference gas so that the test body experiences additional deflective force in the gaps with a non-zero resultant deflection force on the dumbbell and as the result of difference in magnetic susceptibility of test and reference gases and for similar magnetic field strength in the gaps; compensating means including at least one coil not moving with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 23

In an instrument for measuring magnetic suceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but wihtout enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with similar magnetic fields in the gaps have zero resultant; the first body being an open container for receiving a test gas surrounding the dumbbell and penetrating the gaps and into the first body, the second body being a closed container holding a reference gas so that the test body experiences additional deflective force in the gaps with a non-zero resultant deflection force on the dumbbell and as the result of difference in magnetic susceptibility of test and reference gases and for similar magnetic field strength in the gaps; compensating means including at least one coil not moving with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of said gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 24

In an instrument as in claim 16, wherein said test bodies are of similar construction and dimension with the exception of open access for test gas to the interior of the first body.

Claim 25

In an instrument as in claim 17, said test bodies beint flat, hollow cylinders.

Claim 26

In an instrument as in claim 17, said test bodies being hollow spheres.

Claim 27

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with similar magnetic fields in the gaps have zero resultant; the first body being solid and having a smaller displacement than the second body which is filled with a reference gas, both bodies being surrounded by test gas which penetrates the gaps, the second body displacing a larger volume so that a non-zero resultant force acts on the dumbbell for the similar field strength in the gaps; compensating means, including at least one coil not moving with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of saId gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 28

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test bodies disposed in the gaps so that forces acting on them due to the solid material of the test bodies and interaction thereof with similar magnetic fields in the gaps have zero resultant; the first body being solid and having a smaller displacement than the second body which is filled with a reference gas, both bodies being surrounded by test gas which penetrates the gaps, the second body displacing a larger volume so that a non-zero resultant force acts on the dumbbell for the similar field strength in the gaps; compensating means, including at least one coil not moving with said dumbbell and disposed for acting on at least one of said magnetic circuits outside of said gaps to provide for at least one magnetic compensating field, effective respectively in at least one of saId gaps to unbalance the magnetic fields in the gaps for offsetting said non-zero resultant force; pick-up means responsive to the deflection of the dumbbell configuration in response to said deflective force, to provide for control of said compensating means to obtain said magnetic compensating field; and indicating means connected to the pick-up means to provide an indication of the control as provided to the compensating means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 29

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test body disposed in the gaps so that forces acting on them due to the solid material of the test bodies and intaction thereof with the magnetic fields in the gaps, have zero resultant; the first and second gaps being penetrated by a test gas and surrounding said bodies, the first body being hollow and closed, and containing a reference gas, and displacing a larger volume of the test gas than the second body does, so that the test bodies experience additional deflective force in the gaps, the additional deflective force resulting from the different displacement volume of test gas as produced by the first and second bodies, there being a non-zero resultant deflecting force on the dumbbell for similar magnetic field strengths in the gaps accordingly. coil means effective in at least one of said magnetic circuits, but not moving with said dumbbells nor being disposed in said gaps to augment the field of at least one of said magnetic circuits as effective in the respective gap; current driver means connected to the coil means so that said additional deflective force results from the difference in magnetic interaction of the fields in the gaps and the contents of the bodies to unbalance the fields in the gaps for offsetting said non-zero resultant force thereby causing the dumbbell to return to a particular disposition wherein the balancing forces acting on said test bodies are proportional to the product of magnetic field and magnetic field gradient in each of said gaps and where respectively acting on the test bodies in the particular disposition; and indicating means connected to be responsive to provide an indication of the electric current as provided by said current driver means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 30

In an instrument for measuring magnetic susceptibility and which includes a first and a second magnetic circuit respectively with a first and second gap and a first and second test body, respectively located in the first and second gaps, and being interconnected to form a dumbbell configuration which is resiliently suspended but without enveloping current loops, the improvement comprising: the test body disposed in the gaps so that forces acting on them due to the solid material of the test bodies and intaction thereof with the magnetic fields in the gaps, have zero resultant; the first and second gaps being penetrated by a test gas and surrounding said bodies, the first body being hollow and closed, and containing a reference gas, and displacing a larger volume of the test gas than the second body does, so that the test bodies experience additional deflective force in the gaps, the additional deflective force resulting from the different displacement volume of test gas as produced by the first and second bodies, there being a non-zero resultant deflecting force on the dumbbell for similar magnetic field strengths in the gaps accordingly. coil means effective in at least one of said magnetic circuits, but not moving with said dumbbells nor being disposed in said gaps to augment the field of at least one of said magnetic circuits as effective in the respective gap; current driver means connected to the coil means so that said additional deflective force results from the difference in magnetic interaction of the fields in the gaps and the contents of the bodies to unbalance the fields in the gaps for offsetting said non-zero resultant force thereby causing the dumbbell to return to a particular disposition wherein the balancing forces acting on said test bodies are proportional to the product of magnetic field and magnetic field gradient in each of said gaps and where respectively acting on the test bodies in the particular disposition; and indicating means connected to be responsive to provide an indication of the electric current as provided by said current driver means in representation of the difference in magnetic susceptibility between said test material and said reference gas.

Claim 31

In an instrument as in claim 21, wherein said test bodies are of similar configuration, the second body being hollow with access for the test gas to its hollow interior, so that said additional deflective force results from the difference in magnetic interaction of the fields in the gaps and the contents of the bodies.

Claim 32

In an instrument as in claim 21, wherein said second test body is solid and smaller than said first test body, so that the additional deflective force results from the difference in displacement volume of test gas by the two bodies.

Claim 33

In an instrument as in claim 21, wherein said dumbbell is deflected linearly.

Claim 34

In an instrument as in claim 21, wherein said two test bodies have different volume but similar mass and material, so that the additional force results from a difference in displacement volume by the bodies of test gas surrounding them.

Claim 35

In an instrument as in claim 21, wherein the magnetic circuits have a common permanent magnet for energization, the circuits having separate joke and poleshoe structures for the two gaps, the structures each having a coil as the said coil means to provide additional magnetization to both circuits, the current driver means providing Current to said coils to be effective in opposite direction as to the magnetic field components as resulting from this additional energization.

Claim 36

In an instrument as in claim 26, the test bodies being similar in configuration and material, one being filled with reference gas and closed, the other one being open to the test gas.

Claim 37

In an instrument as in claim 21, the coil means including one coil for each said circuits to provide additional magnetization to both circuits, the current driver means providing current to said coils to be effective in opposite direction as to the magnetic field components as resulting from this additional energization.