EP0095265A2 - Steuerung des Trocknungsvorgangs - Google Patents

Steuerung des Trocknungsvorgangs Download PDF

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Publication number
EP0095265A2
EP0095265A2 EP83302532A EP83302532A EP0095265A2 EP 0095265 A2 EP0095265 A2 EP 0095265A2 EP 83302532 A EP83302532 A EP 83302532A EP 83302532 A EP83302532 A EP 83302532A EP 0095265 A2 EP0095265 A2 EP 0095265A2
Authority
EP
European Patent Office
Prior art keywords
materials
drying
moisture
air
controlling
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Withdrawn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
EP83302532A
Other languages
English (en)
French (fr)
Other versions
EP0095265A3 (de
Inventor
Bruce Wallis
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.)
Moisture Control & Measurement Ltd
Original Assignee
Moisture Control & Measurement Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Moisture Control & Measurement Ltd filed Critical Moisture Control & Measurement Ltd
Publication of EP0095265A2 publication Critical patent/EP0095265A2/de
Publication of EP0095265A3 publication Critical patent/EP0095265A3/de
Withdrawn legal-status Critical Current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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
    • F26B25/22—Controlling the drying process in dependence on liquid content of solid materials or objects

Definitions

  • the invention relates to the control of drying or other moisture control operations by the circulation of air or other suitable gas over or through the material the moisture in or on which is to be controlled.
  • drying operations The ability of relatively dry air to extract water from surfaces with which it makes contact is employed in a wide range of industrial and other drying operations.
  • the drying capacity of air being determined solely by its temperature and existing moisture content, drying operations can be and often are precisely thermally controlled in an attempt to optimise efficiency.
  • the prime consideration must always be product quality
  • the present invention arose from a consideration of, but is not necessarily confined to, circumstances in which control of drying capacity of the drying air is of supreme importance to the quality of the product.
  • a method of controlling moisture in or on materials when passing gas over or through the materials wherein the specific enthalpy of the gas is controlled independently of the drying potential thereof.
  • the value of specific enthalpy relative to drying capacity may be controlled by monitoring the temperature and moisture content adding heat and moisture as required.
  • the method may be applied to the drying of material or, alternatively, to the maintenance of a controlled property of moisture on or in materials.
  • moisture on or in materials when passing gas over or through the materials comprising means for controlling the specific enthapy of the gas independently of the drying potential thereof.
  • the addition of heat and moisture is controlled automatically by signals representing temperature and moisture content.
  • the material to be dried consists of green malt, which is a substance which is susceptible to damage if subjected to incremental changes in enthalpy and drying rate greater than predetermined values. It will be assumed that the initial moisture content of the malt is 45% and that it is required to reduce this to something like 4%.
  • the ambient air has a temperature of 150C and a dew point of 100C, though if the drying cycle continues into the night, the moisture content may drop to a dew point of O oC and the temperature, having also dropped to around OOC may, typically, recover to some 3oC by morning.
  • the installation for drying comprises a chamber 2 for containing a quantity of material 4 to be dried, in this example green malt. Air is passed into the chamber 2 through an inlet 6 by means of a fan 8, and having passed over or through the material 4 the air is exhausted through outlet 10 and either voided to atmosphere at opening 12 or returned to the fan 8 via branch pipe 14 for recirculation.
  • a valve 16 controls the proportion of air recirculated with respect to the proportion voided to atmosphere.
  • a mixing unit 20 is also provided in the path between the fan 8 and the inlet 6 providing facility for the introduction of moisture, for example in the form of steam or liquid water through moisture inlet 22 controlled by valve 24.
  • the rate of air flow produced by the fan 8 is controlled by means of a controller 26, and to the extent that the exhaust side of the fan is not satisfied with recirculated air from branch pipe 14, air is introduced through inlet 28 via valve 30.
  • the air introduced through inlet 28 will normally be moist ambient air but in certain circumstances may be relatively or absolutely dry air.
  • the temperatures t of the air circulating in the apparatus is determined at various positions by means of sensors Tl, T2, T3 and T4.
  • the moisture content m of the circulating air is similarly determined at corresponding locations by moisture meters Ml, M2, M3 and M4.
  • ambient air is drawn from inlet 28 through valve 30 by fan 8 and, heated in heating unit 18 and moistened as required in the mixing unit 20 so as to produce the desired enthalpy and drying potential, is introduced into the material 4 in chamber 2 via inlet 6.
  • the enthalpy of the input air is increased gradually whilst controlling the drying potential so as not to damage the material 4.
  • the control of drying capacity independently of specific enthalpy is effected by introduction into the air entering the chamber of quantities of moisture controlled by a signal ml provided by sensor Ml.
  • the moisture introduced may originate from the atmosphere, any recirculated exhaust air or, predominantly at this phase, by injection into the mixing unit 20, and the input air moisture signal is therefore used to control the valves 16, 24, and 30.
  • the initiation phase therefore proceeds with gradual warming of the material without drying.
  • the exhaust air leaving the chamber 2 via outlet 10 may be recirculated or voided to atmosphere.
  • the process is continued until the conditions recorded by sensors M3 and T3 have reached predetermined values or until the conditions at a predetermined zone within the material 4, as determined by sensors M2 and T2, have reached predetermined values.
  • the temperature and the moisture content of the air within the material 4 may be determined by a series of probes at different levels, and the sensors T2 and M2 shown in the figure are to be taken as representative of such probes.
  • the second phase of the process is one of free drying.
  • the specific enthalpy is further increased, but now the drying capacity of the air is also allowed to increase according to the requirements of the process and the material, for example as to whether the main requirement is for thermal efficiency or the safety of the product. It is to be understood that the requirements may vary throughout the process.
  • the increase of drying capacity is still controlled independently of the increase of specific enthalpy. At least some of the exhaust air is conveniently recirculated during this process, and the requirement for the injection of moisture through valve 24 is accordingly adjusted. In exceptional circumstances dry air will be introduced through inlet 28. Data used in the control of the valves accordingly may include signals indicative of the moisture content for the time being of both input and recirculated exhaust air.
  • evaporative cooling generally means that the temperature of the product does not rise to the value of the input air.
  • the temperature of the product as measured by probe T2 begins to increase without any corresponding increase in the moisture content of the air in the material as determined by M2
  • the end of free drying is indicated and the inset of the third phase - restricted drying - in which water removal cannot continue at the former rate.
  • the moisture content of the material may be, typically, 7%, and in order to reduce this to the 4% required, it is convenient to increase the drying potential of the air so as to shorten the process. This may be effected by:-
  • the free drying phase may be integrated with the initiation phase inasmuch as some drying could take place from the outset. Nevertheless, the drying capacity of the air will be controlled together with, but independently of, specific enthalpy.
  • the example described above is one of batch drying wherein the three drying phases - distinct or overlapping - take place in the same spatial zone but at different (distinct or overlapping) periods of time.
  • the invention is equally applicable to continuous processing wherein a portion of a material is made subject to the conditions of the first phase in a first zone and is then moved successively to second and third zones maintained at the conditions respectively of the second and third phases. Successive portions of the material follow the first mentioned portion through the three zones.
  • the equivalent of the overlapping of the phases in the batch process can be afforded by providing zones intermediate the above-mentioned zones and providing in the intermediate zones conditions intermediate those of the adjacent zones.
  • the invention has been described primarily in relation to drying and this is likely to be its major application. However, in the storage of certain products such as fruit or vegetables, it may be required to maintain or even increase the moisture content of the product whilst circulating air or other gas over or through it, and the invention is to be understood as extending to such application.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)
  • Drying Of Gases (AREA)
EP83302532A 1982-05-21 1983-05-05 Steuerung des Trocknungsvorgangs Withdrawn EP0095265A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8214951 1982-05-21
GB8214951 1982-05-21

Publications (2)

Publication Number Publication Date
EP0095265A2 true EP0095265A2 (de) 1983-11-30
EP0095265A3 EP0095265A3 (de) 1984-11-14

Family

ID=10530543

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83302532A Withdrawn EP0095265A3 (de) 1982-05-21 1983-05-05 Steuerung des Trocknungsvorgangs

Country Status (5)

Country Link
EP (1) EP0095265A3 (de)
JP (1) JPH0663702B2 (de)
CA (1) CA1254737A (de)
GB (1) GB2120120A (de)
NO (1) NO831732L (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989001595A1 (en) * 1987-08-18 1989-02-23 National Research Development Corporation Grain drying
DE4037443A1 (de) * 1990-11-24 1992-05-27 Mann & Hummel Filter Vorrichtung zum trocknen von schuettgut
FR2681673A1 (fr) * 1991-09-19 1993-03-26 Semada Ingenierie Procede et installation de sechage de materiaux granulaires.
EP0936430A1 (de) * 1998-02-16 1999-08-18 Eric Julien Verheecke Verfahren und Vorrichtung für die Kontrolle des Wassergehalts von in einem geschlossenen Raum gelagerten Produkten
NL1011760C2 (nl) * 1999-04-09 2000-10-10 Tno Werkwijze en inrichting voor het drogen van producten.
FR2824757A1 (fr) * 2001-05-21 2002-11-22 Oddeis Procede de traitement de produits par de l'air, dispositif de traitement de produits et produits ainsi traites
WO2004002905A1 (de) * 2002-07-01 2004-01-08 Regina Kolb Verfahren zur steuerung von niedertemperaturtorcknung von feuchtgut
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

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IE940232A1 (en) * 1994-03-15 1995-09-20 Midland Malting Res Ltd Malt production

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2030098B2 (de) * 1969-06-18 1975-04-03 Friedrich Wilhelm Castelnaudary Ebersohl (Frankreich)
DE3022067A1 (de) * 1979-06-14 1981-01-08 Hoover Ltd Steuerungen fuer trockenmaschinen

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB245263A (en) * 1924-12-09 1926-01-07 Vivian Elkington Improvements in or relating to the drying of agricultural or horticultural products such as hops, seeds or the like
GB647336A (en) * 1948-12-15 1950-12-13 Hope S Heating & Engineering L Air-conditioning apparatus
ES379040A1 (es) * 1969-05-12 1972-08-01 Termoelectronica Genia Ltda Procedimiento para desecar alimentos.
GB1332116A (en) * 1969-10-17 1973-10-03 Michnik H E A Kiln drying
US3614074A (en) * 1969-11-14 1971-10-19 Moore Dry Kiln Co Direct-fired kiln furnace control system
JPS498855U (de) * 1972-04-25 1974-01-25
JPS5057856A (de) * 1974-02-05 1975-05-20
JPS5436104A (en) * 1977-08-26 1979-03-16 Nec Corp Tripartite communication circuit
JPS6021315B2 (ja) * 1978-06-02 1985-05-27 株式会社 サタケ 穀物の調湿装置
JPS55123980A (en) * 1979-03-16 1980-09-24 Satake Eng Co Ltd Automatic controller for grain drier
JPS55150473A (en) * 1979-05-07 1980-11-22 Satake Eng Co Ltd Low temperature dehumidifying drying method of and apparatus for grain drying

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2030098B2 (de) * 1969-06-18 1975-04-03 Friedrich Wilhelm Castelnaudary Ebersohl (Frankreich)
DE3022067A1 (de) * 1979-06-14 1981-01-08 Hoover Ltd Steuerungen fuer trockenmaschinen

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989001595A1 (en) * 1987-08-18 1989-02-23 National Research Development Corporation Grain drying
DE4037443A1 (de) * 1990-11-24 1992-05-27 Mann & Hummel Filter Vorrichtung zum trocknen von schuettgut
US5182871A (en) * 1990-11-24 1993-02-02 Filterwerk Mann & Hummel Gmbh Apparatus for drying bulk materials
FR2681673A1 (fr) * 1991-09-19 1993-03-26 Semada Ingenierie Procede et installation de sechage de materiaux granulaires.
US6134953A (en) * 1998-02-16 2000-10-24 Verheecke; Eric Process and device for controlling the water content in products stored in an enclosure
FR2775076A1 (fr) * 1998-02-16 1999-08-20 Eric Verheecke Procede et dispositif de controle de la teneur en eau de produits stockes dans une enceinte
EP0936430A1 (de) * 1998-02-16 1999-08-18 Eric Julien Verheecke Verfahren und Vorrichtung für die Kontrolle des Wassergehalts von in einem geschlossenen Raum gelagerten Produkten
NL1011760C2 (nl) * 1999-04-09 2000-10-10 Tno Werkwijze en inrichting voor het drogen van producten.
WO2000062000A1 (en) * 1999-04-09 2000-10-19 Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno Method and apparatus for drying products
FR2824757A1 (fr) * 2001-05-21 2002-11-22 Oddeis Procede de traitement de produits par de l'air, dispositif de traitement de produits et produits ainsi traites
WO2002095312A1 (fr) * 2001-05-21 2002-11-28 Oddeis S.A. Procede de traitement de produits par de l'air, dispositif de traitement de produits et produits ainsi traites
US7024799B2 (en) 2001-05-21 2006-04-11 Oddeis S.A. Method for treating products with air, a product treatment device and the products thus treated
WO2004002905A1 (de) * 2002-07-01 2004-01-08 Regina Kolb Verfahren zur steuerung von niedertemperaturtorcknung von feuchtgut
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
AU2006352202B2 (en) * 2006-12-22 2010-08-12 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
CN101631597B (zh) * 2006-12-22 2012-08-29 Gea工艺工程有限公司 喷雾干燥器设备和通过调节进气流量来控制喷雾干燥器设备的方法
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

Also Published As

Publication number Publication date
JPH0663702B2 (ja) 1994-08-22
GB2120120A (en) 1983-11-30
NO831732L (no) 1983-11-22
JPS58217183A (ja) 1983-12-17
EP0095265A3 (de) 1984-11-14
CA1254737A (en) 1989-05-30
GB8313709D0 (en) 1983-06-22

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Effective date: 19850715

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Inventor name: WALLIS, BRUCE