US 11,965,904 B2Granted

Method for measuring densities based on circular magnetic levitation

AssigneeZhejiang University

InventorsPeng Zhao, Chengqian Zhang, Fu Gu, Xuechun Zhang, Jun Xie, Jianzhong Fu

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Abstract

A sample to be measured is placed in a medium solution between two circular magnets to ensure that the sample to be measured is levitated in a set circular area between the two circular magnets, and a levitation position of the sample to be measured in the magnetic field is measured. The density of the sample is calculated according to formula (I): ρ s = ρ m + χ m - χ s g ⁢ μ 0 ⁢ ( B r ⁢ ∂ B z ∂ r + B z ⁢ ∂ B z ∂ z ) . Compared to the prior art, the method of the present disclosure provides a novel method for measuring a density of a substance, in which the involved device is easy to operate and has low cost, and the measurement results are easy to observe and have high accuracy.

Claims9

Dependent claims

A method for measuring a density based on circular magnetic levitation, comprising:

placing a sample to be measured in a medium solution located between two circular magnets to ensure that the sample to be measured is levitated in a set circular area between the two circular magnets;
measuring a levitation position of the sample to be measured in a magnetic field;
and
calculating the density of the sample to be measured according to formula (I):
ρ
s
=
ρ
m
+
χ
m
-
χ
s
g
⁢
μ
0
⁢
(
B
r
⁢
∂
B
z
∂
r
+
B
z
⁢
∂
B
z
∂
z
)
;
wherein:
ρs is the density of the sample to be measured, g/cm3;
ρm is a density of the medium solution, g/cm3;
χs is a magnetic susceptibility of the sample to be measured, dimensionless;
χm is a magnetic susceptibility of the medium solution, dimensionless;
g is a gravitational acceleration, m/s2;
μ0 is a vacuum permeability, N/A2;
Br and Bz are respectively a radial magnetic field intensity and an axial magnetic field intensity at the levitation position;
r is a levitation radius of the sample to be measured in the medium solution being a distance from a center line of the two circular magnets to the sample to be measured;
and
z is a levitation height of the sample to be measured in the medium solution being a distance from an upper surface of a lower magnet to the sample to be measured;
and
wherein a distance between the two circular magnets satisfies:
(1) a curve expressed by a formula
B
r
⁢
∂
B
r
∂
r
+
B
z
⁢
∂
B
r
∂
z
=
0
does not completely coincide with a center line of the two circular magnets;
and
(2) a gradient of the curve expressed by an expression
B
r
⁢
∂
B
r
∂
r
+
B
z
⁢
∂
B
r
∂
z
in r direction is greater than 0.

91 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/147,721Filed 13 Jan 2021
Priority: CN 202010041028.515 Jan 2020
Published: US 2021/0215589 A115 Jul 2021
Granted: 23 Apr 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G01N 9/08
Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity: by measuring buoyant force…
G01N 9/12
By observing bodies wholly or partially immersed in fluid materials: by observing the depth of immersion of the bodies, e.g. hydrometers
G01N 9/18
By observing the depth of immersion of the bodies, e.g. hydrometers: special adaptations for indicating, recording, or control
G01N
Investigating or analysing materials by determining their chemical or physical properties