EP0479204A1 - Method for continuous moisture control in drying processes and equipment for performing such a method - Google Patents

Method for continuous moisture control in drying processes and equipment for performing such a method Download PDF

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Publication number
EP0479204A1
EP0479204A1 EP91116694A EP91116694A EP0479204A1 EP 0479204 A1 EP0479204 A1 EP 0479204A1 EP 91116694 A EP91116694 A EP 91116694A EP 91116694 A EP91116694 A EP 91116694A EP 0479204 A1 EP0479204 A1 EP 0479204A1
Authority
EP
European Patent Office
Prior art keywords
drying
gas
accordance
equipment
temperature
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP91116694A
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German (de)
English (en)
French (fr)
Inventor
Dino Guglielminetti
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
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Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0479204A1 publication Critical patent/EP0479204A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/06—Controlling, e.g. regulating, parameters of gas supply
    • F26B21/10—Temperature; Pressure

Definitions

  • the present invention relates to equipment which allows continuous moisture control of manufactured articles subjected to drying and/or desiccation using heated gas flows consisting of two or more sensors which measure the gas temperature at the inlet and outlet of the drying system and optionally in the intermediate process phases, connected to a microprocessor or microcontroller allowing setting, varying and controlling of said temperatures in accordance with the processing requirements by operating appropriately the gas flow heaters and/or flow generators and/or the handling systems and/or mechanical, pneumatic or electrical systems which intervene in the drying and/or desiccation process.
  • Measurement of moisture content in drying processes known heretofore, in particular for textiles is performed with humidistats based on measurement of electrical conductivity or thermo-stats and timers which regulate temperature for a given time or two control thermo-stats which set an initial and a final temperature. All these methods display various shortcomings which make their use ineffective and especially give results with low reproducibility because they can be influenced by the humidity in the air or sudden variations in the temperatures as well as in the quantity of liquid, water or solvents present in the manufactured articles at the beginning of the process.
  • the present invention overcomes the above shortcomings and offers the advantage of a very wide field of applications and extreme flexibility in operation thanks to equipment consisting of two or more sensors connected to a microprocessor or microcontroller system on which are easily set the data required and which permit continuous control of said parameters by acting on members used for the heating of the gas flow and/or the generators of said flow and/or on the handling system and/or other mechanical, pneumatic or electrical systems which intervene in the drying and/or desiccation process.
  • the equipment thus enables setting, changing and controlling continuously the moisture content of the manufactured articles by measuring the temperature of the gas, normally air, at the outlet of the drying system, and comparing it with that of the gas at the inlet. It also permits stopping the process when the best moisture content for the materials or for the subsequent operation of the process to which they are to be subjected is reached.
  • FIG. 1 shows a block diagram of the equipment, given here by way of nonlimiting illustration.
  • the gas flow generator is indicated by reference number 10 while 11 indicates the gas inlet duct, 12 the heaters for the gas at the inlet, 13 the drying environment, 14 the gas outlet stack, 15 the sensors and 16 the microprocessor or microcontroller system connected to the sensors and to the gas heater 12.
  • the broken lines represent connections between the microprocessor or microcontroller system and any other sensors or, as specified above, with other mechanical, pneumatic, electrical systems which intervene in the drying and/or desiccation process.
  • the gas flow generators can be blowers, compressors, compressed gas tanks, etc.
  • the heaters can consist of steam or superheated water heating batteries, various types of heat exchangers, electrical resistances, burners, etc.
  • the drying environment can be a fixed or mobile drying chamber with or without bulkheads.
  • the sensors can be any type of instrument designed to measure variations in the temperature of a gas such as thermometers, thermocouple probes, thermal resistances probes, pyrometers, telecameras, infrared detectors, etc., and in particular, depending on the preferred version, platinum thermal resistances with stainless steel covering are used.
  • the microprocessor or microcontroller system can be any microprocessor microcontroller control system equipped with appropriate software and hardware allowing performance of the required operations, in particular there has been used a MICRO-GAM Compact programmer produced by S.A.T.E. s.n.c.
  • the gas flow is held uniform during the drying process and the microprocessor or microcontroller system acts on the heaters, thus varying the gas flow temperature, and on the opening and/or closing of the bulkheads to allow homogenization and conditioning.
  • the programme used provides:
  • FIG. 1 can constitute a unit of a higher order of system consisting of several of said units arranged in series and in which the material to be dried is made to pass from one unit to another.
  • each of the various units will be controlled in an interactive manner with the others by using the microprocessor or microcontroller system.
  • one of the sensors is installed immediately after the inlet gas heating element while another is in the outlet stack.
  • T1 and T2 of the first sensor respectively are assigned.
  • T4 represents the temperature difference which there should be at the end of the drying process between the inlet gas and the outlet gas and said difference will be a function of the residual moisture content of the manufactured article to be dried and can be modified at will by the above mentioned adjustments to allow adaptation of the process to any requirement.
  • this system affords inlet gas temperature regulation by modifying it in accordance with the requirements of the programme loaded as the outlet gas temperature approaches the final value, thus permitting optimization of processing time without subjecting the manufactured articles to uselessly high temperatures during the drying phases which they do not require.
  • the temperature variations during the process are represented schematically in the diagram shown in FIG. 2 wherein on the axis of the abscissas are shown the times and on that of the ordinates the temperatures and in which T1 and T3 represent the initial temperatures measured respectively by the inlet and outlet sensors while T2 and T4 represent the respective final temperatures. It is clear that by merely changing the data for the required temperatures the drying system can be quickly adapted to extremely diverse manufactured articles and hence requiring equally diverse working conditions.
  • Test material twisted mixed wool acrylic yarn skein.
  • test material was soaked and wrung out and subjected to the drying process under the following conditions:
  • T1 and T3 are 57 C and is a function of the moisture content at the beginning of the cycle in the fibre to be dried (approximately 400%).
  • Homogenization time at 80 °C 15'.
  • Time for conditioning to surrounding temperature 10'.
  • Total time employed for the process 145'.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)
  • Treatment Of Fiber Materials (AREA)
EP91116694A 1990-10-02 1991-09-30 Method for continuous moisture control in drying processes and equipment for performing such a method Withdrawn EP0479204A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT2161690 1990-10-02
IT02161690A IT1243062B (it) 1990-10-02 1990-10-02 Apparecchiatura per il controllo in continuo dell'umidita' in processi di asciugatura

Publications (1)

Publication Number Publication Date
EP0479204A1 true EP0479204A1 (en) 1992-04-08

Family

ID=11184380

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91116694A Withdrawn EP0479204A1 (en) 1990-10-02 1991-09-30 Method for continuous moisture control in drying processes and equipment for performing such a method

Country Status (2)

Country Link
EP (1) EP0479204A1 (it)
IT (1) IT1243062B (it)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0648992A1 (fr) * 1993-10-13 1995-04-19 Esswein S.A. Dispositif de régulation de la température de chauffage d'air de séchage d'une machine lavante-séchante ou séchante
ES2129362A1 (es) * 1997-06-09 1999-06-01 Tecnofrut S L Sistema inteligente de secado superficial de frutos, autorregulable.
WO2008077399A1 (en) * 2006-12-22 2008-07-03 Gea Process Engineering A/S A method of controlling a spray dryer apparatus by regulating an inlet air flow rate, and a spray dryer apparatus
US10591213B2 (en) 2017-01-16 2020-03-17 Envirostar, Llc Dryer control systems and methods
CN117783432A (zh) * 2023-12-14 2024-03-29 广东德恩农林发展有限公司 新鲜竹笋干燥程度的检测方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2390690A1 (fr) * 1977-05-14 1978-12-08 Babcock Bsh Ag Procede et dispositif de controle et de commande du sechage de placage en bois et materiaux similaires
FR2506916A1 (fr) * 1981-05-26 1982-12-03 Babcock Bsh Ag Secheur continu pour placages tranches, equipe d'un dispositif de mesure de la largeur des feuilles et d'une regulation du debit et de la temperature de l'air de sechage
US4599808A (en) * 1984-03-20 1986-07-15 The Foxboro Company Drying method and apparatus for fibrous material
US4701857A (en) * 1984-01-25 1987-10-20 Robinson John W Method and apparatus for controlling dryers for wood products, fabrics, paper and pulp
US4922624A (en) * 1988-11-14 1990-05-08 Tharpe John M Method and apparatus for drying lumber

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2390690A1 (fr) * 1977-05-14 1978-12-08 Babcock Bsh Ag Procede et dispositif de controle et de commande du sechage de placage en bois et materiaux similaires
FR2506916A1 (fr) * 1981-05-26 1982-12-03 Babcock Bsh Ag Secheur continu pour placages tranches, equipe d'un dispositif de mesure de la largeur des feuilles et d'une regulation du debit et de la temperature de l'air de sechage
US4701857A (en) * 1984-01-25 1987-10-20 Robinson John W Method and apparatus for controlling dryers for wood products, fabrics, paper and pulp
US4599808A (en) * 1984-03-20 1986-07-15 The Foxboro Company Drying method and apparatus for fibrous material
US4922624A (en) * 1988-11-14 1990-05-08 Tharpe John M Method and apparatus for drying lumber

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0648992A1 (fr) * 1993-10-13 1995-04-19 Esswein S.A. Dispositif de régulation de la température de chauffage d'air de séchage d'une machine lavante-séchante ou séchante
FR2711232A1 (fr) * 1993-10-13 1995-04-21 Esswein Sa Dispositif de régulation de la température de chauffage d'air de séchage d'une machine lavante-séchante ou séchante.
ES2129362A1 (es) * 1997-06-09 1999-06-01 Tecnofrut S L Sistema inteligente de secado superficial de frutos, autorregulable.
WO2008077399A1 (en) * 2006-12-22 2008-07-03 Gea Process Engineering A/S A method of controlling a spray dryer apparatus by regulating an inlet air flow rate, and a spray dryer apparatus
US8402672B2 (en) 2006-12-22 2013-03-26 Gea Process Engineering A/S Method of controlling a spray dryer apparatus by regulating an inlet air flow rate, and a spray dryer apparatus
US10591213B2 (en) 2017-01-16 2020-03-17 Envirostar, Llc Dryer control systems and methods
CN117783432A (zh) * 2023-12-14 2024-03-29 广东德恩农林发展有限公司 新鲜竹笋干燥程度的检测方法

Also Published As

Publication number Publication date
IT9021616A1 (it) 1992-04-02
IT1243062B (it) 1994-05-23
IT9021616A0 (it) 1990-10-02

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