DE3324050A1 - DEVICE FOR IMPLEMENTING A GAS-SHAPED MEDIUM INTO A FURNACE OR THE LIKE. - Google Patents

Abstract

1. Device for the pulsating supply of a combustable gas or air to a combustion chamber or suchlike, particularly for heating a tunnel kiln in the ceramic industry with gas above the ignition temperature by means of a lance extending into the combustion chamber connected to the supply line for the medium to be supplied, which supply line comprises a magnet valve being pulsating controllable, characterized in that onto the lance (11) a mixing nozzle for the stream of the medium (31) coming from the lance and to be supplied into the combustion chamber (4) is mounted, which nozzle has a cross-section continuously tapered in the direction of the stream and which nozzle has several openings (26) by means of which gas (stream 32) may be drawn from the combustion chamber (4) and is supplied to same through the mixing nozzle as a focused stream (33).

Description

I.

DIPL-ING. GUIDO ENGELHARDT PATEhTANWALT

7990 Friodrichehafan

Dr.-Ing.Wolfgang Leisenberg
6312 Laubach

Device ± ur pulsed introduction of a gaseous medium into a furnace or the like.

The invention relates to a device for. pulsed introduction of a flammable gas or of Air into a combustion chamber or the like, in particular for firing one operated above the ignition temperature Tunnel furnace of the ceramic industry with gas, by means of a lance protruding into the combustion chamber, which is connected to a connected to a pulsed controllable solenoid valve supply line for the medium to be introduced is.

Most of the ovens used in the ceramic industry are designed as tunnel ovens. These consist of prin Basically from two countercurrent heat exchangers connected in series with a combustion zone in between. The for Air mass flow required for heating and cooling the material to be fired corresponds roughly to the mass flow of the fuel

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good and is wholly or largely passed through the burn zone. This is usually in the burn zone Between 700 and 125o degrees C heated air with sufficient oxygen content for combustion is available.

The burner used here has the task of maintaining the required temperature with a homogeneous temperature distribution and to generate an oxidizing furnace atmosphere. In addition, to adjust the power distribution over 'the Oven cross-section or oven length is an individual one. Adjustment of each burner required. . ·

To generate the exit velocity and the oxidizing velocity necessary for a homogeneous temperature distribution Combustion, the vast majority of burners today are operated with the addition of secondary air.

Due to the countercurrent principle in the tunnel furnace, however, the amounts of air in the heating and cooling zones cannot release to get voted. Therefore, when secondary air is added to the burners, a corresponding part of the heat exchange in the cooling zone required air before entering'die burning zone removed from the oven. This hot air is generally ^ mine used for drying. However, the heat requirement of the dryer is often neither correct in terms of time nor quantity with the heat demand of the furnace, so that in addition to heat losses The waste heat from the furnace cannot be fully utilized in the pipes, especially on weekends. Next to

frequently encountered. Amount of heat for ceiling and wall cooling combine measures to reduce the amount of flue gas and the recovery of the heat contained in the flue gas * - 'steady increase in the heat supply, which neither from. Dryer. Still usefully recycled by other institutions

■ can be. The efficiency of the dryer also increases to the extent that the air used for drying is supplied with energy through intermediate heating. Large amounts of air available from the oven are therefore undesirable in terms of optimum dryer efficiency. . _k

In order to reduce the amount of hot air to be discharged from the oven, it is already known to mix air and gas =, with By means of the mechanical energy of the gas pressure, hot air is sucked in from the cooling zone of the furnace via pipes from the burner will. The burner output is controlled via gas pulses, their duration and frequency individually can be adjusted.

With this method, secondary air temperatures of up to 600 degrees C can be achieved without the use of fans, The disadvantage here, however, is that the secondary air temperature remains considerably below the furnace chamber temperature and a insulated piping system for supplying the combustion .. air is required.

It is also known to use a burner lance in pulses Inject gas under high pressure into the combustion chamber. The gas is mixed with the furnace atmosphere through the Injector effect. The power of the burner is achieved by a Throttle valve individually adjusted.

The disadvantage here is that the mixture of the gas with the

The furnace atmosphere only takes place in the combustion chamber, where a strong yellow flame creates a reducing atmosphere. • To counteract the local lack of oxygen, be

■ the burners are switched individually sequentially. Also on this Way, however, cannot be prevented from local

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Reductions occur, which lead to discoloration of the firing material to lead. Furthermore, especially in the area of the preliminary fire and with high burner outputs, a complete Combustion of the gas is not ensured because the gas cloud with the furnace atmosphere in the range of temperatures " can get below the ignition temperature without sufficient mixing with the oxygen-containing furnace atmosphere would have taken place. Therefore, they are in the first row of burners conventional burners with the addition of secondary air are provided for this system.

The object of the invention is to provide a device of the aforementioned Kind of creating an oxidizing, flame-free combustion without any addition of secondary air or a homogenization of the atmosphere in the combustion chamber is possible. The mixing of the added fuel gas or the air with the gas present in the combustion chamber should be extremely intense in this case, and also through the. exiting free jet, intensive circulation and further mixing can be achieved. The construction effort, with to whom this is to be achieved should be kept low, = Furthermore, trouble-free operation should be guaranteed.

According to the invention, this is done in a device for: pulsed introduction of a flammable gas or of ■. ■■ Air into a combustion chamber or the like .. · reached by means of a lance protruding into this, in that one of the lances this exiting jet of the medium to be introduced into the combustion chamber is attached to the mixing nozzle, which is shown in Direction of flow a steadily tapering. Has cross section and provided with one or more openings

3.O is about which to mix the injected medium with. of the furnace atmosphere, gas can be sucked in from the combustion chamber and introduced into it as a bundled jet by means of the mixing nozzle.

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It is useful here, the mixing nozzle in the area ■ '. in front of the outlet opening with a conical shape and / or to provide convexly curved inner lateral surfaces and the openings machined into this for sucking in gas from the combustion chamber on the side of the lance in to arrange their end region in the wall, the openings as bores with a circular cross-section should be formed and provided in a cylindrical part of the mixing nozzle to which, in cross section continuously tapering area of the mixing nozzle.

To determine the speed of the gas " To increase the jet, a throttle can be provided at its end protruding into the mixing nozzle.

It is also attached to the mixing nozzle with a flow channel arranged at a distance from the lance

to equip forming casing, through which the mixing nozzle, preferably fresh air or through the openings another gas can be supplied. It is advantageous here to arrange the casing so that it can be adjusted in height and through this D cover all or part of the side openings of the mixing nozzle. In this way, the mixing nozzle can if necessary both fresh air is added and this is partially mixed with the furnace atmosphere.

The lance, mixing nozzle, and / or sheath should due to the high temperatures in the combustion chamber, completely or partially made of a heat-resistant material, preferably made of silicon carbide.

For introducing different media into the combustion chamber can, in order to be able to burn different fuels by means of the device, the lance with a mixing chamber

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be equipped / to each ^ with an impulsive '■ controllable solenoid valve provided feed lines are to be connected. Firing a kiln can for example from a fire with gas to a Firing "with oil therefore in a very short time and without that Structural measures are required to be converted, using compressed air as the propellant gas and for atomizing the oil can be used.

Will the. according to the invention designed mixing nozzle for.

When firing a kiln is used, it is advisable to to combine several mixing nozzles into a jointly controlled group, to which a control unit can be assigned " is, by means of which the solenoid valves of the mixing nozzles can be individually controlled in such a way that when the constant opening duration, the opening frequency depending on the temperature in the combustion chamber via a controller is adjustable. The switching of the solenoid valves should always be offset, and should also be in the area at least one mixing nozzle of a group in the combustion chamber a thermocouple can be arranged, which is connected to the controller. is bound.

The device designed according to the invention for the pulsed introduction of a combustible gas or of Air into a combustion chamber or the like is not only very simple in terms of its structural design and therefore without it Difficulties to produce in an economical way, but also operationally reliable, but above all becomes one oxidizing flame-free combustion without the addition of. Secondary air allows. Namely, one on the lance Put on a mixing nozzle, which has a steadily tapering cross section and openings, see above. is in the mixing nozzle intensive mixing of the injected medium

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using the full available gas pressure of approx. 1-- 3 bar with the furnace atmosphere made / because gas is sucked in from the combustion chamber through the openings and penetrated into it as a bundled jet will. Due to the injector effect, an intensive mixing of the supplied Medium from the combustion chamber. In addition, the high temperature of the atmosphere and the Injector action produced a strongly oxidizing combustion with increasing gas pressure already reached in the nozzle, so that a bundled hot gas jet emerges from the nozzle, its speed To a large extent. is determined by the gas pressure and in the order of magnitude of conventional ones operated with secondary air Burners lies. Sufficient circulation of the furnace atmosphere is thus ensured.

The emerging bundled jet draws in furnace atmosphere in accordance with the injector principle and, in addition to the circulating effect, causes a further admixture of hot furnace atmosphere. Tests have shown that at gas pressures of more than 0.8 bar an oxidizing, often flame-free combustion is achieved. In this way, the reducing atmosphere is avoided in the case of direct injection and the maximum possible air preheating is achieved without any pipelines. Will about the ^;

Mixing nozzle designed according to the invention no combustible I.

Gas, but air brought into a room, is on one j

multiple ways an upheaval of the existing atmosphere and |

to achieve equalization. γ

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In the drawing is an embodiment of the device designed according to the invention for pulse-wise Introduction of a gaseous medium into a furnace or the like., Shown, which is explained in detail below is. Here show:

Fig. 1 the arranged in a combustion chamber of a tunnel furnace device, partially in Cut,

Fig. 2 shows the device according to FIG. 1 with one of the lance carrying the mixing nozzle

arranged sheathing and

3 shows a plurality of mixing nozzles which are combined to form a group and can be regulated jointly Fig. 1 in a schematic representation.

The device shown in Fig. 1 and designated 1o is used to introduce a medium into the combustion chamber 4 of a tunnel kiln 1 and consists of one in the ceiling 2 of the tunnel kiln 1 by means of a plate 12 incorporated Schürloch 3 held lance 11 as well a mixing nozzle 21 placed on its end protruding into the combustion chamber 4 To achieve medium is at the end of the lance 11 a Throttle 13 attached. .

The mixing nozzle 21 consists of a cylindrical part 23; . and a continuously tapering area in cross section 24, the inner surface 25 of which is convexly curved. In the cylindrical part 23 of the mixing nozzle 21 are openings 26, in the embodiment shown

this two holes opposite each other, incorporated, by the, as shown by the arrows denoted by 32, by the from the Throttle 13 exiting jet 31 gas from the combustion chamber 4 is sucked in. In the mixing nozzle 21 there is thus already an intensive mixing of the supplied Medium with gas sucked in from the combustion chamber 4. And this mixture emerges as a bundled beam 3 3 from the Outlet opening 22 of the mixing nozzle 21 and is burned without flame in the combustion chamber 4.

To use the mixing nozzle 21 different media in To be able to introduce the combustion chamber 4 is the lance 11 provided with a mixing chamber 14 to the supply lines 15, 17 and 19 are connected. -In each of the supply lines 15, 17 and 19 is a solenoid valve 16, 18 and. 2o used so that in order to z. B. alternately firing with gas or atomized oil to be able to make a combustible via line 15 Gas that flows through the mixing chamber 14, or this through the lines 17 and 19 oil and .Preßluft in the Mixing chamber 14 are mixed together, is supplied. If necessary, "quickly and without structural measures required, a change in the lighting must be made. The power control is carried out by Switching the solenoid valves -16 or 18 and 2o, their switching frequency and opening duration of the power of the mixing nozzle 21 are proportional.

Occurs due to the mode of operation of the furnace in cases where the tunnel furnace 1 is not or only partially operated as a continuous heat exchanger, lack of oxygen in the Combustion chamber 4, .so the mixing nozzle 21 can also air

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are fed. For this purpose, as shown in the device 1o ^r in FIG. 2, the lance 11 is provided with a casing 27 which is arranged adjustable in height by the path s, ¹ so that a flow channel 28 is created. Depending on the position of the casing 27, fresh air (lower layer) can thus be drawn. Gas can be sucked in from the combustion chamber 4 (upper layer) or a mixture of both (middle layer). In addition to saving the fan energy and the stepless adjustment of the furnace atmosphere / air ratio, this addition principle has the advantage that air is only sucked in when gas is flowing.

To increase the exit impulse, the air can also be supplied under pressure Partial control of the amount of air through the gas flow, since the resistance in the mixing nozzle during the gas injection 21 is greatly reduced and the amount of air is increased considerably.

If the mixing nozzle is used to fire a tunnel oven, it is appropriate, as is shown schematically in FIG. 3, to have several mixing nozzles 21 ', 21 ^I! , 21 ¹¹¹ , into which the combustible gas flows via a common ■ gas supply line 15 'as well as pulsed controllable solenoid valves 16', 16 ¹¹ , 16 ¹¹¹ , to form a group. By means of a control device 41, the opening time of one of the solenoid valves 16 ', 16 "or 16'" is individually adjusted according to the required power distribution, while the opening frequency for the mixing nozzles of a group is jointly controlled by a controller 42 as a function of the temperature in the combustion chamber 4 , .that is measured via a thermocouple'43, is given via the control unit 41 y6r.

June 27, 1983 e-1
A 5364

Claims (1)

I. DIPL.-ING. GUIEX) ENGELHARDT PATENT ADVOCATE 7990 Friedrichshafen Dr. «" Ing. Wolfgang Leisenberg
Laubach Claims 1.) Device for the pulsed introduction of a vj / flammable gas or air into a combustion chamber Or the like, in particular for firing a tunnel kiln operated above the ignition temperature the ceramic industry with gas, by means of a lance protruding into the combustion chamber, which is connected to a ' a pulsed controllable solenoid valve provided supply line for the to be introduced Medium is connected, thereby marked ze i c h η et, that on the lance (11) one exiting from this A mixing nozzle (21) which absorbs a jet of the medium (31) to be introduced into the combustion chamber (4) is attached which is steadily changing in the direction of flow having young cross-section and those with an or · / · R - COPY several openings (26) are provided, via which the injected medium (31) is mixed with the furnace atmosphere gas (jet 32) from the combustion chamber (4) and by means of the mixing nozzle (21) ίϊί this can be introduced as a bundled beam (33). 2. Device according to claim 1,
characterized, that the mixing nozzle (21) in the area in front of the outlet opening (22) is conical and / or convex ■ is provided with curved inner lateral surfaces (25), 3. Apparatus according to claim 1 or 2,. characterized, that in the mixing nozzle (21) incorporated openings (26) for sucking in gas (jet 32) from the combustion ■ space (4) are provided to the side of the lance (11) in the end area in the wall of the mixing nozzle (21) '. 4. Apparatus according to claim 3,
characterized, that the openings (26) as bores with circular Cross-section are formed. 5. Device according to one or more of claims 1 to 4, characterized, 332405 that the openings (26) in a cylindrical part (23) of the mixing nozzle (21) are incorporated and that the steadily tapering cross-section is attached to this Area (24) of the mixing nozzle (21) connects. 6. Device according to one or more of claims 1 to 5, characterized, that the lance (11) is provided with a throttle (13) at its end protruding into the mixing nozzle (21). 7. Device according to one or more of claims 1 to 6, ' characterized, that the mixing nozzle (21) has a flow channel (28) arranged at a distance from the lance (11) forming casing (27) is provided, through which the mixing nozzle (21) preferably over its openings (26) fresh air or another gas can be supplied. 8. Apparatus according to claim 7, characterized, that the casing (27) is arranged to be adjustable in height and that through this the lateral openings (26) the mixing nozzle (21) can be wholly or partially covered, 9. Device according to one or more of claims 1 to 8, characterized", that the lance (11) / the mixing nozzle (21) and / or the casing (27) entirely or partially from one heat-resistant material, preferably made of silicon carbide. 10. The device according to one or more of claims 1 to 9,. characterized, that for introducing different media into the combustion chamber (4) the lance (11) with a mixing chamber (14) is provided, to each of which with a pulsed controllable solenoid valve (16, 18, 2o) provided feed lines (15, 17, 19) connected are. 11. Device according to one or more of claims 1 to Vo, characterized, that in each case several mixing nozzles (21 ', 21 ¹¹ , 21''') of a kiln (1) are combined to form a jointly controllable group. 12. The device according to claim 11, characterized in that 332405C that the group (mixing nozzles '21 ', 21 ¹¹ , 21 ¹¹¹ J is assigned a control device (41), by means of which the solenoid valves (1.6 ¹ , 16 ", 16 "·) are individually controllable in such a way that, with a variable, constant opening duration, the opening frequency can be set as a function of the temperature in the combustion chamber (4) via a controller (42). 13. Apparatus according to claim 12, characterized, that the switching of the solenoid valves (16 ', .16 ", 16'") laterally offset. 14. Apparatus according to claim 12 or 13, characterized, that a thermocouple (43) is arranged in the region of at least one mixing nozzle (21 ') of a group in the combustion chamber (4) which is connected to the regulator (42). June 27 (1983 e-1
A 5364.