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US-12618701-B2 - Probe apparatus and method for measuring cryogenic exhaust flow

US12618701B2US 12618701 B2US12618701 B2US 12618701B2US-12618701-B2

Abstract

An apparatus for measuring flow of cryogen exhaust gas from a freezer includes a flow probe with a resistive heater and a flow probe control. The flow probe control is coupled to the flow probe and the flow probe control includes a control circuit configured to operate the resistive heater at a first temperature for a first period of time, operate the resistive heater at a second temperature for a second period of time, and determine a heat transfer coefficient at the flow probe. The first temperature and the second temperature are different and at least one of the first and second temperatures is greater than a predetermined threshold temperature. A related method is also provided.

Inventors

  • John Griffiths

Assignees

  • MESSER INDUSTRIES USA, INC.

Dates

Publication Date
20260505
Application Date
20231218

Claims (11)

  1. 1 . An apparatus, comprising: a flow probe comprising a resistive heater; and a flow probe control coupled to the flow probe and comprising a control circuit configured to: operate the resistive heater at a first temperature for a first period of time, operate the resistive heater at a second temperature for a second period of time, and determine a heat transfer coefficient at the flow probe, wherein the first temperature and the second temperature are different and at least one of the first temperature and the second temperature is greater than a predetermined threshold temperature.
  2. 2 . The apparatus of claim 1 , wherein the flow probe control is further configured to indirectly determine a temperature of cryogen exhaust gas present at the flow probe.
  3. 3 . The apparatus of claim 2 , wherein the temperature of the cryogen exhaust gas is determined based on a first measured current through the resistive heater operated at the first temperature, and a second measured current through the resistive heater operated at the second temperature.
  4. 4 . The apparatus of claim 2 , wherein the flow probe control is configured to determine the heat transfer coefficient and the temperature of the cryogen exhaust gas from information received from the resistive heater.
  5. 5 . The apparatus of claim 2 , wherein the heat transfer coefficient and the temperature of the cryogen exhaust gas are determined without a sensor separate from the resistive heater.
  6. 6 . The apparatus of claim 1 , wherein the flow probe control is configured to continuously alternate operating the resistive heater at the first temperature for the first period of time, and operating the resistive heater at the second temperature for the second period of time.
  7. 7 . The apparatus of claim 1 , wherein the predetermined threshold temperature is 100° Fahrenheit (38° Celsius).
  8. 8 . The apparatus of claim 1 , wherein the flow probe is configured to be mounted in an exhaust duct of the freezer.
  9. 9 . The apparatus of claim 1 , further comprising a cryogen control valve, wherein the flow probe control is further configured to cause the cryogen control valve to stop a flow of cryogen when the heat transfer coefficient is determined to be less than a predetermined heat transfer threshold.
  10. 10 . The apparatus of claim 1 , wherein the control probe is further configured to operate the resistive heater at a third temperature for a third period of time, the third temperature being different from the first temperature and the second temperature.
  11. 11 . The apparatus of claim 1 , further comprising: a second flow probe comprising a second resistive heater, wherein the flow probe control is also coupled to the second flow probe and the control circuit is further configured to: operate the second resistive heater at the second temperature during the first period of time, and operate the second resistive heater at the first temperature during the second period of time, such that an operating temperature of the second flow probe remains out of phase with an operating temperature of the flow probe.

Description

BACKGROUND OF THE INVENTION The present embodiments relate to apparatuses and methods for measuring cryogenic environments used for processing products such as for example food products. Industrial apparatus for the processing of products, such as food products, often employ various devices for measuring characteristics and/or operating conditions of the apparatus and the environment in which the apparatus is operating. One example industrial apparatus is an industrial freezer that may be used to freeze food products during processing of such food products for storage, transport, and/or further processing. A cryogen may be used to quickly and efficiently freeze or chill such food products. The cryogen is typically controlled and/or dispensed at extremely low temperatures to quickly freeze the food products in an industrial environment. The extremely low temperatures of the cryogen used in industrial freezers present challenges for their efficient and safe operation in an industrial setting. As a result, existing industrial freezer implementations may suffer from various drawbacks. For example, exhaust systems, which are used in industrial freezer settings to expel spent cryogen, may fail because their components (e.g., exhaust blower, exhaust duct, exhaust measurement devices, etc.) become fouled and/or inoperable due to the accumulation of ice from the extremely low temperatures in which the components must operate. When the exhaust system components and/or related systems fail, become inoperable, and/or deliver inaccurate information, freezer operations must cease to inspect and correct such failures, ensure appropriate safety protocols are in place, perform maintenance, and/or verify proper operation before the freezing of the food products can be resumed. Thus, as a result of these and other deficiencies, existing industrial freezer implementations suffer from increased processing times, higher costs, and risks to operator safety. Therefore, there exists a need for improved apparatuses and methods that can operate continuously and efficiently in the extreme environments of industrial freezing processes. SUMMARY OF THE INVENTION This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. An apparatus for measuring flow of cryogen exhaust gas from a freezer is disclosed herein. The apparatus may comprise a flow probe comprising a resistive heater and a flow probe control coupled to the flow probe. The flow probe control may comprise a control circuit configured to operate the resistive heater at a first temperature for a first period of time, operate the resistive heater at a second temperature for a second period of time, and determine a heat transfer coefficient at the flow probe, wherein the first temperature and the second temperature are different, and at least one of the first temperature and the second temperature may be greater than a predetermined threshold temperature. A method of determining a flow velocity of a cryogen exhaust gas from a freezer is also disclosed herein. The method may comprise energizing the flow probe with a first voltage to maintain a first temperature for a first period of time, energizing the flow probe with a second voltage to maintain a second temperature for a second period of time, wherein the second temperature is different from the first temperature. The method further includes determining a heat transfer coefficient at the flow probe, and determining a velocity of the cryogen exhaust gas at the flow probe based on the heat transfer coefficient. Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, reference may be had to the following description of exemplary embodiments considered in connection with the accompanying drawing Figures, of which: FIG. 1 is a schematic view of an example cryogenic processing environment that includes one embodiment of a probe apparatus in accordance with the present disclosure. FIG. 2 is a schematic view of a portion of the cryogenic processing environment of FIG. 1 showing an example probe apparatus. FIG. 3 is schematic view of an example probe assembly that may be used in the probe apparatus of FIG. 2. FIG. 4 is a circuit diagram of an example circuit that may be used in the probe apparatus of FIG. 2. FIG. 5 is a flow chart illustrating an example method of determining a flow of cryogen exhaust gas in accordance with the present disclosure. FIG. 6 is a schematic view of an example cryogenic processing environment that includes another embodiment of a probe apparatus in accordance with the present disclosure. FIG. 7A is a schematic view of a portion of the cryogeni