RU2441187C2 - Tunnel furnace for ceramic items - Google Patents

Tunnel furnace for ceramic items Download PDF

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Publication number
RU2441187C2
RU2441187C2 RU2007125862/02A RU2007125862A RU2441187C2 RU 2441187 C2 RU2441187 C2 RU 2441187C2 RU 2007125862/02 A RU2007125862/02 A RU 2007125862/02A RU 2007125862 A RU2007125862 A RU 2007125862A RU 2441187 C2 RU2441187 C2 RU 2441187C2
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RU
Russia
Prior art keywords
burners
furnace
devices
substance
combustion
Prior art date
Application number
RU2007125862/02A
Other languages
Russian (ru)
Other versions
RU2007125862A (en
Inventor
Джузеппе ПИФФЕРИ (IT)
Джузеппе ПИФФЕРИ
Original Assignee
Сакми Форни С.П.А.
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
Priority to ITRE2006A000094 priority Critical
Priority to IT000094A priority patent/ITRE20060094A1/en
Application filed by Сакми Форни С.П.А. filed Critical Сакми Форни С.П.А.
Publication of RU2007125862A publication Critical patent/RU2007125862A/en
Application granted granted Critical
Publication of RU2441187C2 publication Critical patent/RU2441187C2/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27BFURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/36Arrangements of heating devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23NREGULATING OR CONTROLLING COMBUSTION
    • F23N1/00Regulating fuel supply
    • F23N1/002Regulating fuel supply using electronic means
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23NREGULATING OR CONTROLLING COMBUSTION
    • F23N3/00Regulating air supply or draught
    • F23N3/002Regulating air supply or draught using electronic means
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27BFURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/40Arrangements of controlling or monitoring devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00Arrangements of controlling devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D21/00Arrangements of monitoring devices; Arrangements of safety devices
    • F27D21/02Observation or illuminating devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27MINDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
    • F27M2001/00Composition, conformation or state of the charge
    • F27M2001/15Composition, conformation or state of the charge characterised by the form of the articles
    • F27M2001/1504Ceramic articles
    • F27M2001/1508Articles of relatively small dimensions
    • F27M2001/1517Tiles

Abstract

FIELD: heating.
SUBSTANCE: furnace comprises two opposite side walls, a horizontal roller conveyor designed to retain and move a layer of tiles inside the furnace, the first and second set of burners arranged along two side walls and facing the opposite wall. Each burner of the first set is only equipped with a nozzle to produce axial frame to heat the central zone of the tunnel. Each burner of the second set is equipped with a nozzle for radial-directed flame to heat the zone near the side wall of the tunnel. Each burner of the first and second sets is connected to the common channel for combustible gas and accordingly to the first and second channels for a substance that sustains combustion, accessories to detect discrepancies in dimensions compared to design dimensions of items that go out from the furnace, a control unit to produce data that arrive from accessories for detection, accessories for control of speed of flow of the substance that sustains combustion and arrives to the burners of the second set arranged in the second channel for the substance that sustains combustion, accessories for control of speed of flow of the substance that sustains combustion, control of which is carried out by means of an accessories control unit for adjustment in compliance with the data received from the detection accessories.
EFFECT: invention provides for efficient control of furnace operation to produce ceramic items with requested space characteristics.
11 cl, 3 dwg

Description

The invention relates to a tunnel kiln for ceramic products.
In more detail, the present invention relates to a tunnel furnace equipped with a roller conveyor on which ceramic products are located, which, for example, may be tiles.
As you know, the heating of tunnel ovens occurs through two rows of heaters (burners), one on each side of the furnace, usually working on methane, which are located on the side walls of the tunnel of the furnace and facing opposite walls.
On each side of the tunnel, preferably two rows of burners are located, one of which is above and the other below the roller conveyor.
The burners are arranged in groups, and their power comes from one gas channel, and each of the groups of burners is equipped with a valve, which is controlled by temperature control systems.
The tile firing cycle is set with great accuracy using the firing chart, which establishes sequential heating of the tile, starting from the oven inlet, at which the tile is held at a given temperature for a specified time, and the tile is controlled to cool until it reaches the furnace exit.
Various types of burners are known, as well as the characteristic arrangement of the burners, which is used to better control the operation of the furnace. However, the successively increasing cross-sectional size of the furnaces and the use of more and more rapid firing in order to increase productivity have revealed some functional disadvantages of traditional furnaces that have a negative impact on their efficiency.
In particular, the disadvantages of conventional furnaces are manifested when the cross section of the tunnel kiln exceeds a certain size.
In very wide tunnel kilns, an undesirable cross-sectional temperature distribution is observed at which the temperature in the center is higher than at the furnace walls,
This inevitably leads to defects during firing of tiles, the movement of which occurs near the walls of the tunnel, while defects appear as defects in size and shape, for example, lack of flatness, all this leads to an increase in the number of defective products.
To reduce such phenomena, the applicant conducted studies of special types of burners, the action of which is aimed at heating the space inside the tunnel, including the area near the side walls of the tunnel.
In particular, in the patent IT1287626 in the name of the same applicant, a tunnel furnace is described containing two rows of burners having different characteristics, the first row of burners designed primarily to heat the central zone, and the second row of burners designed primarily to heat the zone near the walls of the tunnel.
In the furnace described above, the intensity of gas supply to the burners for predominantly heating the zone near the walls of the tunnel is set by a valve controlled by a control system that changes the gas flow rate in accordance with the temperature measured by special thermocouples located inside the tunnel near the side walls.
Unfortunately, the measurement results obtained from thermocouples located near the side walls are usually influenced by turbulence present along the walls, as well as the proximity of the burners themselves. This means that the temperature values obtained as a result of the measurement are actually correct in relation to the point where the measurements were made, but do not correspond to the temperature that acts in the immediate vicinity of the tiles located on the roller conveyor. Indeed, in the same zone along the side wall, despite the fact that the work occurs at almost the same temperature, at different points the values of the measured temperature will vary significantly.
Therefore, the use of thermocouples placed along the side walls of the tunnel does not lead to effective regulation of the system.
Thus, for the above reasons, there is an urgent need to create a tunnel kiln for ceramic products, which would provide effective regulation without the disadvantages inherent in the prior art, in order to obtain ceramic products with spatial characteristics that would be close to the design (specification) products (design) as much as possible through a simple and rational constructive solution.
The aim of the present invention is to provide a tunnel furnace for ceramic products with such structural and functional characteristics that would satisfy the requirements and at the same time overcome the disadvantages indicated in relation to the prior art.
This goal is achieved by creating a tunnel furnace for ceramic products, as described in claim 1 of the claims of the present invention.
The dependent claims describe preferred and particularly advantageous embodiments of a tunnel kiln for ceramic products according to the invention.
Additional features and advantages of the invention will become more apparent after reading the description below, provided with the accompanying drawings, given as non-limiting examples.
figure 1 presents a side view of a tunnel kiln according to this invention,
figure 2 in magnification shows a partial section taken along the line II-II shown in figure 1,
figure 3 in enlargement shows a partial section taken along the line II-II shown in figure 2.
As shown in the drawings, the tunnel kiln for ceramic products of this invention is generally indicated by 1.
If described in the most general form, the furnace 1 is formed by two opposite side walls 2, the base 3 and the arch 4.
A roller conveyor 5 of a known type is placed inside the furnace 1, while the roller conveyor 5 moves ceramic products, which in this example are tiles 100.
On each side wall of the tunnel 2 there are two rows 31 and 32 of gas burners, which are respectively above and below the roller conveyor 5.
The burners of each of the rows are located inside the recesses 6 made in the side wall 2 of the furnace 1.
Each of the rows of burners includes two sets of different burners, which are indicated as 51 and 52, respectively, while the burners of one set are interpolated with the burners of the other sets.
Thus, four rows of 31, 32 burners are formed, two on one wall and two on the other. Each row 31, 32 consists of two sets of burners. The burners of the two sets of each row are interpolated with each other and with the burners of the other row located on the same wall, and with the burners of the same set, which form a coplanar row on the opposite wall.
In particular, the burners 51, which are called axial burners here, are provided with only one nozzle producing an axially directed flame, so as to mainly heat the central zone of the tunnel, while the burners 52, which are called radial burners here, are equipped with many nozzles for a radially directed flame , so as to mainly heat the area near the side wall of the tunnel.
Alternatively, radial burners 52 may, in addition to nozzles for a radially directed flame, also comprise a nozzle for an axially directed flame.
The power of all burners, axial and radial, comes from a common channel 60 for supplying combustible gas, as is the case in traditional furnaces.
Each of the sets of burners 51 or 52 can be distributed across sectors that serve different temperature zones of the furnace, each of which is equipped with its own devices for regulation and control, which, for simplicity, are not shown in the drawings, while the power of all burners comes from the channel 60 for gas supply.
Heating control elements 70, which may be thermocouples or thermal probes, are located in each of the temperature zones. Preferably, the elements 70 are located in the center, in the above example, at the arch 4 and at the base 3, and the signals they send are sent to devices for regulating and controlling the heating power, which are not shown in the drawings.
According to the present invention and as shown in FIG. 2, the air supply to the axial burners 51 comes from a common air supply channel 510 in which conventional adjusting and controlling devices (not shown) are located, while the air supply to the burners 52 is different channel 520 for air supply.
In particular, additional channels 524 extend from channel 520, each of additional channels 524 leads to one burner 52 of the second set.
In the shown embodiment, the air supply channel 520 is closed by a valve-mounted valve 521 located above the channels 524 and connected to a control unit 522, which is programmed to regulate the air flow pressure and, thus, the flow rate supplied to the respective radial burners 52 .
In particular, the control unit 522 controls the pressure of the air supplied to the radial burners, and thus, the air flow in accordance with the signals received from special devices 523, which will be discussed in more detail below, these devices detect deviations from the dimensions of the products coming out from kiln 1 specified in accordance with tile specification 100.
In fact, if there are defects found in the tile 100 located on its side and leaving the furnace 1, the control unit 522, having received signals from the detection devices 523, immediately intervenes, changing the amount of air supplied to the radial burners 52, and thereby changing appropriate temperature. This is achieved by keeping the flow of gas supplied to the radial burners 52 constant, the same as supplied to the axial burners 51, as a result of which the heating power remains constant.
Naturally, the necessary changes in the air flow are small and, therefore, they will not adversely affect the operation of the furnace 1 as a whole.
To achieve optimal control, the control unit 522 constantly receives pressure data from pressure sensors 81, 82 located respectively in the channel 510 for supplying air to the axial burners 51 and in the channel 520 for supplying air to the radial burners 52.
For the purposes of the present invention, the detection of “defects” in the tiles 100 can be performed by personnel who work on a keyboard connected to the control unit 522, or this can be done by using an automatic detection system to control the size and flatness of tiles of the type described in Italian application RE2006A000007 in the name of the same applicant, which is not described in detail here.
Obviously, other devices suitable for detecting tile defects and for directing the corresponding signal to control unit 522 can be used.
The signal directed to the control unit 522 is converted to the value of the pressure difference between the two air flows directed respectively to the axial burners 51 and to the radial burners 52.
In operating mode, the furnace 1 is started, maintaining the same air pressure when feeding it to the axial and radial burners. Then, but only if there are defects in the tiles leaving the furnace 1 detected by the detection devices 523, the control unit sends a signal to the valve 521 in order to further open or close the channel in accordance with the desired pressure change, while the pressure change is calculated the control unit 522 in accordance with the signal from the devices 523 for detection, which indicates the presence of defects in the tile.
In fact, the initial parameters of the furnace change to a small extent. As an alternative to using a valve 521 regulating several radial burners 52, for example, burners in a predetermined heating zone, as described above, the valve can be applied to each of the radial burners 52, and the valves can be located in the channels 524. In this case each control valve is equipped with a pressure sensor located below the valve, which sends a signal to the control unit (system) 522.
Since the control system 522 uses pressure sensors to monitor the pressure difference between the air flow to the axial burners 51 and the radial burners 52, the pressure sensors can be replaced by special systems to determine the pressure difference ΔP, which directly direct the ΔP value to the control system 522.
Naturally, the control of the furnace as a whole is performed by the central electronic unit, which also controls the operation of the control unit 522.
As is clear from the description, the tunnel kiln for ceramic products according to this invention meets the requirements and overcomes the disadvantages indicated in the introduction to the prior art.
Due to the change in the air flow rate supplied to the radial burners, carried out by a single control unit, the furnace 1 of the present invention allows to obtain the required dimensions and flatness for all the tiles coming out of it, and there are no differences between the tiles coming from the central or side zones of the furnace, significantly reduced amount of waste.
In addition, the furnace according to this invention can be easily manufactured using traditional furnaces with minor structural changes.
It is obvious that a person skilled in the art, in order to satisfy special and possible requirements, can make numerous modifications and changes to the tunnel kiln for ceramic products described above, all of which do not go beyond the protection framework provided by the present invention, as defined by the following the claims.

Claims (11)

1. A tunnel kiln (1) for ceramic products, containing two opposite side walls (2), a horizontal roller conveyor (5), designed to hold and move the tile layer (100) inside the kiln (1), the first set of burners (51) and a second set of burners (52) located along two side walls and facing the opposite wall, each burner (51) of the first set is provided with only an axial flame nozzle in order to heat the central zone of the tunnel, with each burner (52) of the second set equipped with at least with a nozzle for a radially directed flame so as to heat the zone near the side wall of the tunnel, each burner (51, 52) of the first and second sets is connected to a common channel (60) for combustible gas and, respectively, with the first (510) and second (520 ) channels for supporting the combustion substance, while the furnace contains devices (523) for detecting size mismatches in comparison with the design dimensions of products leaving the furnace (1), a control unit (522) for receiving data from devices (523) for detection, adapt (521) for regulating the flow rate of the combustion-supporting substance entering the burners (52) of the second set located in the second channel (520) for the combustion-supporting substance, devices (521) for controlling the flow rate of the combustion-supporting substance controlled by the unit control (522), which is programmed to control devices (521) for regulation in accordance with the data received from devices (523) for detection.
2. The furnace (1) according to claim 1, characterized in that the second channel (520) for the combustion-supporting substance contains a collector, from which many channels (524) for the combustion-supporting substance depart, each channel (524) leads to one burner ( 52) a second set of burners.
3. The furnace (1) according to claim 2, characterized in that the adjustment devices (521) are located in each of the channels (524) that feed the burners (52) of the second set.
4. The furnace (1) according to claim 2, characterized in that the control devices (521) are located in the collector for the combustion-supporting substance.
5. The furnace (1) according to claim 1, characterized in that the second set of burners (52) is formed by a plurality of burners arranged alternately with the burners (51) of the first set.
6. The furnace (1) according to claim 1, characterized in that the burners (52) of the second set further comprise an axial flame nozzle.
7. The furnace (1) according to claim 1, characterized in that each side wall (2) contains two rows (31, 32) of burners, one of which (31) is located above the roller conveyor (5), and the second (32) located below the roller conveyor (5).
8. The furnace (1) according to claim 7, characterized in that in each row (31, 32) the burners of the first and second sets are arranged alternately.
9. The furnace (1) according to claim 1, characterized in that the detection devices (523) comprise an automatic system for determining the size and / or flatness of a ceramic product exiting the tunnel.
10. The furnace (1) according to claim 1, characterized in that the devices for regulating the flow rate comprise an actuated valve (521).
11. The furnace (1) according to claim 1, characterized in that it further comprises devices (81, 82) for determining pressure, located respectively in the first channel and in the second channel for supporting the combustion substance, while the devices for determining pressure are connected to the unit Management (522).
RU2007125862/02A 2006-07-28 2007-07-10 Tunnel furnace for ceramic items RU2441187C2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
ITRE2006A000094 2006-07-28
IT000094A ITRE20060094A1 (en) 2006-07-28 2006-07-28 Tunnel kiln for ceramic products

Publications (2)

Publication Number Publication Date
RU2007125862A RU2007125862A (en) 2009-01-20
RU2441187C2 true RU2441187C2 (en) 2012-01-27

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RU2007125862/02A RU2441187C2 (en) 2006-07-28 2007-07-10 Tunnel furnace for ceramic items

Country Status (10)

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EP (1) EP1884730B1 (en)
CN (1) CN101113873B (en)
AT (1) AT535768T (en)
BR (1) BRPI0703052A (en)
ES (1) ES2377240T3 (en)
IT (1) ITRE20060094A1 (en)
MX (1) MX2007008526A (en)
PL (1) PL1884730T3 (en)
PT (1) PT1884730E (en)
RU (1) RU2441187C2 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101943519B (en) * 2009-07-08 2012-08-08 王文庭 Green brick automatic regulating device
CN102679726B (en) * 2012-05-24 2014-05-07 江苏丰东炉业股份有限公司 Natural gas heating furnace and smoke exhaust system thereof
CN102759269B (en) * 2012-08-06 2015-03-04 泉州恒灼热力机械有限公司 Double-combustion-supporting igniting combustor of roller kiln
CN102809285B (en) * 2012-08-08 2014-02-26 广东四通集团股份有限公司 Large-section high-efficiency energy-saving type gas tunnel kiln
CN106196169B (en) * 2016-09-18 2019-04-09 北京航天动力研究所 A kind of replaceable ignition flame radial spray device of applied at elevated temperature
IT201900012288A1 (en) * 2019-07-18 2021-01-18 Sacmi Forni Spa METHOD AND OVEN FOR COOKING BASIC CERAMIC ARTICLES SUBSTANTIALLY FLAT

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1152483A (en) * 1995-09-13 1997-06-25 丹尼利机械厂联合股票公司 Method of heating-furnace temp. having controlled soaking oxidation sorrounding and furnace embodied
IT1287623B1 (en) * 1996-02-22 1998-08-06 Sacmi Forni Spa Cooling element, particularly for tunnel ovens
IT1287626B1 (en) * 1996-02-27 1998-08-06 Sacmi Forni Spa Single-layer kiln for tiles
US6454562B1 (en) * 2000-04-20 2002-09-24 L'air Liquide-Societe' Anonyme A' Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Oxy-boost control in furnaces
DE10058186A1 (en) * 2000-11-23 2001-06-13 Sacmi Forni Spa Single-layer oven for firing ceramic tiles incorporates a tunnel housing a motor-driven gravity roller table for transporting a layer of tiles and two series of burners with different ratings in the tunnel's sidewalls.
FR2829232B1 (en) * 2001-09-06 2004-08-20 Air Liquide Method for improving the temperature profile of an oven
CN2539120Y (en) * 2002-05-22 2003-03-05 邯郸钢铁股份有限公司 Decentralized reverse control heating furnace
ITMO20030218A1 (en) * 2003-07-25 2005-01-26 Tck Societa A Responsabilita Li Mitata Control system of a ceramic kiln.
JP4998655B2 (en) * 2004-09-30 2012-08-15 Jfeスチール株式会社 Combustion control method for continuous heating furnace

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PT1884730E (en) 2012-03-02
EP1884730B1 (en) 2011-11-30
RU2007125862A (en) 2009-01-20
CN101113873A (en) 2008-01-30
EP1884730A3 (en) 2010-03-17
EP1884730A2 (en) 2008-02-06
AT535768T (en) 2011-12-15
CN101113873B (en) 2011-08-10
BRPI0703052A (en) 2008-03-25
ES2377240T3 (en) 2012-03-23
PL1884730T3 (en) 2012-05-31
MX2007008526A (en) 2008-10-29
ITRE20060094A1 (en) 2008-01-29

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Effective date: 20140711