Automatical in situ control of the confined environment of metabolically active produce

Patent metadata

Field	Value
Publication number	US-11259533-B2
Application number	US-201716302852-A
Country	US
Kind code	B2
Filing date	May 18, 2017
Priority date	May 18, 2016
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A control system for controlling the storage of metabolically active produce in a defined confined environment. The control system comprises gas analyzing and pressure measurement means including a control unit for determining an adjusted gas medium composition of the confined environment for protecting the produce against metabolic degradation. An operating/actuating means for adapting the gas medium in the confined storage environment is based on the determined adjusted gas medium composition. The control unit is adapted for determining the adjusted gas medium composition based on a mathematical model of the system that determines a metabolic coefficient of the produce by combining measured changes of gas composition in the confined environment with dynamic pressure changes in the confined space. The value of the metabolic coefficient is used as input for a control algorithm to continuously adjust the gas composition in the confined space in response to the metabolic activity of the produce.

First claim

What is claimed is:

1. A control system for controlling of respiratory produce in a confined environment, said control system comprising an operator/actuator, a gas analyser and an atmospheric pressure sensor, and a control unit adapted to receive signals of the gas analyser and of the atmospheric pressure sensor and adapted to generate an output signal responsive to a change of gas composition and pressure in the confined environment, which output signal drives the operator/actuator to adjust the gas composition in the confined environment, wherein the control unit is programmed:
1) to calculate a respiration coefficient as a function of a measured gas composition in the confined environment and as a function of the pressure in the confined environment, which respiration coefficient is determined by the control unit based on a mathematical model that at least uses the measured gas composition and pressure out of at least two consecutive times over a selective time period in the confined environment, wherein the mathematical model provides a rate of the change with time of a gas quantity (n i ) as a rate of exchange (r i ) with the respiratory produce of that gas, times mass (m) of respiratory produce, and a change of total quantity of gasses (n) minus a sum of rates of exchange of all gasses times a gas fraction x i * obtained from the output of the atmospheric pressure sensor, where the respiration coefficient (RQ) is a defined mathematical function (f) of the rate of exchange (r i ) of the gas, and where the gas fraction (x i *) is taken as the gas fraction in the atmosphere when the atmospheric pressure is larger or the same as the pressure in the confined environment, or as the gas fraction in the confined environment when the atmospheric pressure is lower than in the confined environment,
2) as a function of the calculated respiration coefficient to determine an adjusted gas medium composition, and
3) to generate an output signal that drives the operator/actuator to control the respiratory produce.

2. The system according to claim 1 , wherein the control unit is programmed to determine the adjusted gas medium composition based on a mathematical model of the system that at least uses measured gas composition and pressure at least two consecutive times over a selective time period in the confined environment to calculate in real time said respiration coefficient;
the adjusted gas medium composition being determined as a function of the calculated respiration coefficient in the confined environment, whereby the respiration coefficient is calculated in real time as the solution of the following system of equations:

{

dn
i

dt

=

r
i

⁢
m

+

(

dn
dt

-

∑
j

⁢

(

r
j

)

⁢
m

)

⁢

x
i
⋆

n
i

=

x
i

⁢

PV
RT

;

⁢

n
=

∑
i

⁢

n
i

x
i
⋆

=

x
i

⁢
H

+

x

i
,
a

⁡

(

1
-
H

)

RQ
=

f
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(

r
i

)

Assignees

• Univ Leuven Kath
• Vlaams Centrum Voor Bewaring Van Tuinbouwproducten Vzw
• Optiflux Nv

Inventors

• Bessemans Niels
• Nicolai Bart
• Verboven Pieter
• Verlinden Bert

Classifications

• A23B7/144

  in the form of gases, e.g. fumigation; Compositions or apparatus therefor · CPC title

• A23B7/148 Primary

  in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O · CPC title

• G05D21/00

  Control of chemical or physico-chemical variables, e.g. pH value · CPC title

• G05D16/028

  Controlling a pressure difference (control of flow G05D7/00) · CPC title