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EP-4737831-A1 - FLUID BED DEVICE AND METHOD FOR MONITORING A FLUID BED DEVICE

EP4737831A1EP 4737831 A1EP4737831 A1EP 4737831A1EP-4737831-A1

Abstract

The present invention relates to a fluid bed device (100) with a vessel (102) for fluidizing particulate food material (150). The device (100) includes a temperature sensor arrangement (120) with spatially distributed temperature sensing elements (122) that monitor the spatial temperature distribution (TD1-TD7, TD1'-TD7') of the material (150). A processing device (130) acquires a time series (TS, TS') of these temperature distributions, analyzing each sensing element's (122) temporal variation (SV, SV') in temperature readings. If any temporal variation (SV, SV') exceeds a defined threshold (T), the device (100) generates a signal indicating an abnormal condition within the vessel (102). A method (300) of monitoring a fluid bed device (100) is also disclosed.

Inventors

  • JONGSMA, Alfred

Assignees

  • Tetra Laval Holdings & Finance S.A.

Dates

Publication Date
20260506
Application Date
20251027

Claims (15)

  1. A fluid bed device (100) comprising: a vessel (102) configured to receive a particulate food material (150) to be fluidized, a temperature sensor arrangement (120) comprising a set of spatially distributed temperature sensing elements (122) configured to sense a spatial temperature distribution (TD1-TD7, TD1'-TD7') of the particulate food material (150), wherein the spatial temperature distribution (TD1-TD7, TD1'-TD7") comprises a temperature reading of each temperature sensing element (122), and a processing device (130) configured to; acquire a time series (TS, TS') of temperature distributions (TD1-TD7, TD1'-TD7') from the temperature sensor arrangement (120), determine, from the time series (TS, TS') of temperature distributions (TD1-TD7, TD1'-TD7'), for each temperature sensing element (122), a temporal variation (SV, SV') of the temperature readings of the respective temperature sensing element (122), detect whether any one of the temporal variations (SV, SV') exceeds a threshold (T), and in response to detecting that at least one of the temporal variation (SV, SV') exceeds the threshold (T), generate a signal indicative of an abnormal operating condition in the vessel (102).
  2. The fluid bed device (100) according to claim 1, wherein the temporal variation (SV) comprises a standard deviation, a variance, a variation in rate, a variation in magnitude, a variation in frequency, a pattern-wise variation, a trend-wise variation, a volatility or an anomaly in temperature change.
  3. The fluid bed device (100) according to claim 1 or 2, wherein the abnormal condition corresponds to a de-fluidized state of the particulate food material (150) in at least a portion of the vessel (102).
  4. The fluid bed device (100) according to any one of the preceding claims, wherein the set of spatially distributed temperature sensing elements (122) are arranged in the vessel (102) and configured to extend longitudinally into fluidized particulate food material (150) in the vessel (102).
  5. The fluid bed device (100) according to any one of claim 1-3, wherein the set of spatially distributed temperature sensing elements (122) are arranged on an exterior surface (104) of the vessel (102).
  6. The fluid bed device (100) according to any one of claim 1-3, wherein a first subset (122a) of the set of spatially distributed temperature sensing elements (122) are arranged in the vessel (102), and wherein a second subset (122b) of the set of spatially distributed temperature sensing elements (122) are arranged on an exterior surface (104) of the vessel (102).
  7. The fluid bed device (100) according to any one of the preceding claims, wherein the temperature sensor arrangement (120) comprises a fiber Bragg grating (124).
  8. The fluid bed device (100) according to claim 7, wherein the fiber Bragg grating (124) extends along a linear path or along a curved path.
  9. The fluid bed device (100) according to any one of the preceding claims, wherein the temperature sensor arrangement (120) comprises a first fiber Bragg grating (124) extending along a first path and a second fiber Bragg grating (124) extending along a second path.
  10. The fluid bed device (100) according to claim 9, wherein the first and/or second path is a linear path, extending along a horizontal plane (HP) of the vessel (102).
  11. The fluid bed device (100) according to claim 9, wherein the first and/or second path is a curved path, extending along a horizontal plane (HP) of the vessel (102).
  12. The fluid bed device (100) according to any one of the preceding claims, wherein the processing device (130) is further configured to adapt a control parameter of the fluid bed device (100) in response to receiving the signal.
  13. The fluid bed device (100) according to any one of the preceding claims, wherein particulate food material (150) is milk powder or baby formula.
  14. A method (300) for monitoring a fluid bed device (100), the fluid bed device (100) comprising: a vessel (102) configured to receive a particulate food material (150) to be fluidized, and a temperature sensor arrangement (120) comprising a set of spatially distributed temperature sensing elements (122) configured to sense a spatial temperature distribution (TD1-TD7, TD1'-TD7') of the particulate food material (150), wherein the spatial temperature distribution (TD1-TD7, TD1'-TD7') comprises a temperature reading of each temperature sensing element (122), the method (300) comprising: acquiring (S302), by a processing device (130), a time series (TS, TS') of temperature distributions (TD1-TD7, TD1'-TD7') from the temperature sensor arrangement (120), determining (S304), by the processing device (130), from the time series (TS, TS') of temperature distributions (TD1-TD7, TD1'-TD7'), for each temperature sensing element (122), a temporal variation (SV, SV') of the temperature readings of the respective temperature sensing element (122), detecting (S306), by the processing device (130), whether any one of the temporal variations (SV, SV') exceeds a threshold (T), and in response to the processing device (130) detecting that at least one of the temporal variations (SV, SV') exceeds the threshold (T), generating (S308), by the processing device (130), a signal indicative of an abnormal operating condition in the vessel (102).
  15. The method (300) according to claim 14, further comprising adapting (S310), by the processing device (130), a control parameter of the fluid bed device (100) in response to receiving the signal.

Description

Technical Field The invention relates to the field of food production. More particularly, it is related to a fluid bed device. A method for monitoring a fluid bed device is also disclosed. Background In dairy and food production fluidized beds (or fluid beds) are commonly used to further dry and cool powders or similar after drying in a dedicated dryer, such as in a spray dryer. To this end, a fluidized state of the powder is commonly achieved by forcing a fluid through a bulk of the powder to be dried or cooled. In a fluid bed, the powder to be dried or cooled is typically held in a so-called fluidization vessel. The powder bulk in the fluidization vessel is typically brought into a fluidized state by injecting a fluid, typically pressurized air, via fluid distributors or injectors at the bottom of the fluidization vessel. Alternatively, the powder can be brought into a fluidized state mechanically. In such a case, the fluidization vessel is typically vibrated or agitated such that the powder is brought into a fluidized state. When in a fluidized state, the powder behaves like a fluid. This means for example that lighter objects of the powder float, that the powder levels in communicating vessels level out, and the powder flows out of openings in fluidization vessel like any liquid. In order to be able to efficiently dry or cool powder in a fluid bed, the powder needs to be maintained in a fluidized state at all times. However, the fluidized state of the powder can be compromised during certain conditions such that the powder enters into a de-fluidized state or non-fluidized state. The problem of de-fluidization is generally most pronounced when the fluid bed is used for drying powder. De-fluidization typically occurs when the particles making up the powder become too sticky. When particles of the powder stick together to form larger agglomerates the resulting agglomerates or particles become too big to be brought into a fluidized state in the fluidization vessel. The agglomerates will then sink to the bottom of the fluidization vessel. When too many of these agglomerates appear at the bottom of the fluidization vessel, the feed of pressurized air can be blocked locally and cause a de-fluidization of the powder. De-fluidization essentially means that locally, or globally, the powder is no longer in a fluidized state. If the onset of such de-fluidization is not addressed properly and quickly enough agglomerates will continue to form and build up in the fluidization vessel. When too many or too large agglomerates have accumulated in the fluidization vessel, the fluidization vessel must be cleaned. Typically, such cleaning will have to be performed manually, which is time-consuming and results in undesired and lengthy downtime of the fluid bed. It is common practice to measure the level of moisture in the powder entering the fluid bed from e.g. a spray dryer. Such moisture measurements are typically conducted manually on a regular basis, such as once every hour. However, process variations in a dryer upstream the fluid bed can typically occur on a much shorter time base meaning that the moisture level of the powder entering the fluid be can vary and in a worst case result in a de-fluidized state of the powder in the fluidization vessel. Since the capacity of an upstream dryer is generally utilized close to its maximum, even small process variations in the dryer can lead to a de-fluidized state of the powder in the fluidization vessel of the fluid bed. For instance, a change in weather, such as a passing cold front or the daily temperature cycle, can affect the moisture level of the powder entering the fluidization vessel. Hence, there is room for improvement when it comes to avoiding de-fluidization in a fluid bed, and consequently when it comes to reducing the need to clean the fluid bed. Summary It is an objective to at least partly overcome one or more of the above-identified limitations of the prior art. One such objective is to provide a fluid bed device in which abnormal operating conditions, such as a de-fluidized state, are detectable. Another objective is to provide such a device in which abnormal operating conditions are detectable at an early stage. Another objective is to provide such a device that requires less downtime for cleaning. One or more of these objectives, as well as further objectives that may appear from the description below, are at least partly achieved by a fluid bed device, and a method for monitoring a fluid bed device according to the independent claims, embodiments thereof being defined by the dependent claims. A first aspect relates to a fluid bed device. The device comprises a vessel configured to receive a particulate food material to be fluidized, a temperature sensor arrangement and a processing device. The temperature sensor arrangement comprises a set of spatially distributed temperature sensing elements configured to sense a spatial temperature distribution of the parti