Temperature control using applied electromagnetic fields

Patent metadata

Field	Value
Publication number	US-12259284-B2
Application number	US-202017632602-A
Country	US
Kind code	B2
Filing date	Aug 13, 2020
Priority date	Aug 16, 2019
Publication date	Mar 25, 2025
Grant date	Mar 25, 2025

Abstract

Disclosed is a technique for characterizing a product utilizing novel measurements based on the reactive and resistive signals exhibited by the product in an electromagnetic field.

First claim

What is claimed is:

1. A method of analyzing a product to determine its temperature, comprising:
(a) providing a correlation of the actual temperature of a reference product having the composition of a product being analyzed, that is conductive, correlated with the phase angle exhibited by the reference product, at two or more different actual temperatures, wherein the phase angle exhibited by a given product is a function of a reactive signal of the given product and a resistive signal of the given product measured in an electromagnetic field of a given strength and frequency applied to the given product;
(b) applying an electromagnetic field of said given strength and frequency to the product being analyzed, measuring the reactive signal and the resistive signal exhibited by the product being analyzed in said electromagnetic field at said given strength and frequency, and determining the phase angle exhibited by the product being analyzed from the measured reactive signal and resistive signal of the product being analyzed; and
(c) determining the actual temperature of the product being analyzed from the phase angle determined in step (b) in accordance with said correlation.

2. The method of claim 1 wherein at least one of the temperatures at which the correlation is provided is a temperature at which the product being analyzed is partially or completely frozen.

3. The method of claim 1 wherein a plurality of pieces of product are analyzed by passing them through the electromagnetic field, wherein the pieces of product are arrayed in a column along a direction of passage of the pieces through the electromagnetic field and are spaced apart from one another in the column such that a piece of product does not enter the electromagnetic field until the piece immediately ahead of it in the column has exited from the electromagnetic field.

4. A method of analyzing a product to determine the degree of freezing of the product, comprising:
(a) providing a correlation of the degree of freezing of a reference product having the composition of a product being analyzed, that is conductive, correlated with the phase angle exhibited by the reference product, at two or more different degrees of freezing, wherein the phase angle exhibited by a given product is a function of a reactive signal of the given product and a resistive signal of the given product measured in an electromagnetic field of a given strength and frequency applied to the given product;
(b) applying an electromagnetic field of said given strength and frequency to the product being analyzed, measuring the reactive signal and the resistive signal exhibited by the product being analyzed in said electromagnetic field at said given strength and frequency, and determining the phase angle exhibited by the product being analyzed from the measured reactive signal and resistive signal of the product being analyzed; and
(c) determining the degree of freezing of the product being analyzed from the phase angle determined in step (b) in accordance with said correlation.

5. The method of claim 4 wherein at least one of the temperatures at which the correlation is provided is a temperature at which the product is partially or completely frozen.

6. The method of claim 4 wherein a plurality of pieces of product are analyzed by passing them through the electromagnetic field, wherein the pieces of product are arrayed in a column along a direction of passage of the pieces through the electromagnetic field, and are separated from one another in the column such that a piece of product does not enter the electromagnetic field until the piece immediately ahead of it in the column has exited from the electromagnetic field.

7. A method of operating equipment that provides product which is at a temperature within a desired range as it exits the equipment, comprising:
(a) passing a product that is conductive into and through equipment which is capable of subjecting the product within the equipment to at least one adjustable operating condition that is capable of modifying the temperature of the product within the equipment;
(b) applying an electromagnetic field of a given strength and frequency to the product at one or more of (i) a location that is within the equipment or (ii) a location at which the product leaves the equipment or (iii) a location at which the product enters the equipment, measuring a reactive signal and a resistive signal exhibited by the product in the applied electromagnetic field, and determining the phase angle exhibited by the product wherein the phase angle exhibited by a given product is a function of the reactive signal of the given product and the resistive signal of the given product measured in an electromagnetic field of a given strength and frequency applied to the given product;
(c) determining the actual temperature of the product from the measured phase angle in accordance with a predetermined correlation at two or more different actual temperatures of the actual temperature of the product correlated with the phase angle exhibited by a product having the composition of the product being analyzed measured at said applied electromagnetic field of said given strength and frequency; and
(d) when the difference between the actual temperature of the product determined in step (c) and a predetermined set point temperature of the product is more than a predetermined difference value, reducing said difference by adjusting at least one adjustable operating condition within the equipment to modify the temperature of the product in the equipment, so that the temperature of the product as it exits the equipment is within said desired range.

8. The method of claim 7 wherein the product is partially frozen as it exits the equipment.

9. The method of claim 7 wherein the product is completely frozen as it exits the equipment.

10. The method of claim 7 wherein a plurality of pieces of product are analyzed by passing them through the electromagnetic field, wherein the pieces of product are arrayed in a column along a direction of passage of the pieces through the electromagnetic field, and are spaced apart from one another in the column such that a piece of product does not enter the electromagnetic field until the piece immediately ahead of it in the column has exited from the electromagnetic field.

11. The method of claim 7 wherein the at least one adjustable operating condition is any of: the temperature of the gaseous atmosphere within the equipment, the rate at which the gaseous atmosphere is circulated within the equipment; the rate at which gaseous heat transfer medium is fed into the equipment; and the rate at which the product is passed through the equipment.

12. The method of claim 7 wherein liquid or gaseous coolant is applied to the product within the equipment to reduce the temperature of the product or to partially or completely freeze the product, and the at least one adjustable operating condition is any of: the rate at which the coolant is applied to the food product, and the temperature of the coolant that is applied to the product.

13. A method of operating equipment that provides product which is at a temperature within a desired range as it exits the equipment, comprising:
(a) passing a product that is conductive into and through equipment which is capable of subjecting the product within the equipment to at least one adjustable operating condition that is capable of modifying the temperature of the product within the equipment;
(b) applying an electromagnetic field of a given strength and frequency to the product at one or more of (i) a location that is within the equipment or (ii) a location at

Assignees

• Praxair Technology Inc

Inventors

• Israni Sameer H
• Du Xiaotang
• Jampala Soujanya N
• Girard John M
• Zhou Keqin

Classifications

• G01K2207/04

  for conservation purposes · CPC title

• F25D3/005

  combined with heat exchangers · CPC title

• G01K2207/06

  for preparation purposes · CPC title

• G01K7/36 Primary

  using magnetic elements, e.g. magnets, coils (magnetic elements per se H01F) · CPC title

• G01K7/38 Primary

  the variations of temperature influencing the magnetic permeability · CPC title