Non-invasive method for measurement of physical properties of free flowing materials in vessels
Methods and apparatus for measuring physical properties of material in a vessel are provided. In one example, the method includes capturing a response to a vibration initiated by a source in mechanical communication with the vessel, generating a vibration response spectrum based on the response, and calculating at least one value of at least one physical property of the material based on at least one pre-established relationship between the at least one physical property and one or more characteristics of the vibration response spectrum.
1. A method for measuring physical properties of non-gaseous free flowing material in a vessel, the method comprising:
receiving data characterizing the vessel and at least one sample of the material in the vessel;
initiating a vibration on a wall of the vessel by one of an external source or an internal source in mechanical communication with the vessel;
capturing a response to the vibration;
generating a vibration response spectrum based on the response;
determining a search zone within the vibration response spectrum based on a configuration of the vessel, a type of attachment between the vessel and another object, and the at least one sample of the material in the vessel;
determining at least one pre-established relationship between at least one physical property of the material and one or more characteristics of the vibration response spectrum of the search zone;
measuring an ambient temperature within a predefined proximity of the vessel;
determining a difference between the measured ambient temperature and a set process temperature;
computing a correction to the at least one pre-established relationship based on the difference; and
calculating at least one value of at least one physical property of the material based on the at least one corrected pre-established relationship.
2. The method of claim 1 , wherein initiating the vibration includes at least one of initiating a solid body interaction with the wall, initiating a fluid-dynamic interaction with the wall, initiating a ballistic percussion interaction with the wall, or initiating an electro-dynamic interaction with the wall.
3. The method of claim 1 , wherein initiating the vibration includes applying a mechanical load to the outside wall of the vessel, and the mechanical load includes at least one of a single pulse, a pulse train, or a periodic pulse.
4. The method of claim 3 , wherein the mechanical load is modulated according to at least one of amplitude modulation, frequency modulation, pulse modulation, pulse-code modulation, or pulse-width modulation.
5. The method of claim 1 , wherein capturing the response includes:
converting an oscillation into a digital signal;
analyzing the digital signal to calculate one of a wall response time, a damping factor, a signal harmonic spectrum, or a variable characterizing a magnitude of the oscillation; and
adjusting a gain applied to the response.
6. The method of claim 1 , wherein calculating the at least one value includes calculating at least one value of material level in the vessel, material bulk density, kinematic viscosity, or dynamic viscosity of the material.
7. The method of claim 1 , wherein calculating the at least one value includes calculating at least one value of at least one physical property of a homogeneous liquid, a heterogeneous liquid, or a loose solid.
8. The method of claim 1 , wherein calculating the at least one value includes calculating at least one value of at least one physical property of a moving material or a still material.
9. The method of claim 1 , wherein the vessel is one of a silo, a tank, or a pipe.
10. The method of claim 1 , wherein calculating the one or more characteristics of the vibration response spectrum of the search zone is a frequency of one of a spectrum harmonic.