EP3252412A1 - Zinc coating furnace - Google Patents

Abstract

The invention relates to a galvanizing furnace (1) having a galvanizing trough (6) and a furnace housing (2) enclosing the galvanizing trough (6), which has a rectangular cross section. The furnace housing (2) has two opposite longitudinal side walls (4) and two opposite end-side side walls (5) and further comprises burners for heating liquid zinc in the galvanizing trough (6). At least one first receptacle (15) for a burner is provided in each case in the regions of two diagonally opposite corners of the furnace housing (2). In the areas of the two other diagonally opposite corners of the oven housing (2) each have a second receptacle (16) is provided for a burner. The burners are optionally arranged either in the first receptacles (15) or in the second receptacles (16). Flames generated by the burners are each guided in the region between a longitudinal side wall (4) of the furnace housing (2) and the opposite wall of the galvanizing trough (6).

Description

The invention relates to a galvanizing furnace and a method for operating a galvanizing furnace.

Such galvanizing ovens are used in hot dip galvanizing and used for the heating of liquid zinc. The galvanizing furnace generally includes a furnace housing having a galvanizing trough disposed therein. The furnace housing typically has a rectangular cross-section. In this case, the furnace housing has two opposite longitudinal side walls and two likewise opposite end side walls, wherein the longitudinal side walls are larger than the front side walls.

Burners, in particular gas burners, are typically used to heat the liquid zinc in the galvanizing tank. These burners each heat the furnace interior between the walls of the furnace housing and the galvanizing trough by means of a flame tube. Furthermore, electrically heated galvanizing ovens are known.

A widely used burner system for such galvanizing furnaces operates with gas burners in the form of high speed burners. These high-speed burners are provided at diagonally opposite corners of the furnace housing. The high-speed burners are each mounted in an end-side side wall of the furnace housing so that the flame generated by the respective high-speed burner in the gap between a longitudinal side wall of the furnace housing and a side wall of this opposite side wall of the galvanizing trough is. Depending on the size and performance of the galvanizing furnace, several high-speed burners can be mounted one above the other in the diagonally opposite corners of the furnace housing.

To protect against the high flame temperatures of the high-speed burner, the corner regions of the galvanizing trough, which are directly opposite the flame outlets of the high-speed burners, are clad on their outer sides with flame deflectors and thus protected.

During operation of such galvanizing ovens occur wear effects, which in particular the galvanizing is affected. It has been shown that in the course of operation of the galvanizing furnace, a reduction of the wall thickness of the galvanizing trough occurs. As the wear progresses, the wall thickness of the galvanizing trough is reduced so much that the entire galvanizing trough has to be replaced, which requires considerable constructional effort. In particular, it is disadvantageous that significant downtimes of the galvanizing furnace are connected, that is, the availability of the galvanizing furnace is undesirably low.

The invention has for its object to provide a galvanizing furnace and a method for its operation, which allows an increase in the availability of the galvanizing furnace with little design effort.

To solve this problem, the features of the independent claims are provided. Advantageous embodiments and expedient developments of the invention are described in the dependent claims.

The invention relates to a galvanizing furnace having a galvanizing trough and a furnace housing enclosing the galvanizing trough, which has a rectangular cross section. The furnace housing has two opposite longitudinal side walls and two opposite end side walls and further includes burners for heating liquid zinc in the galvanizing trough. In the areas of two diagonally opposite Corners of the oven housing is provided in each case at least one first receptacle for a burner. In the areas of the two other diagonally opposite corners of the oven housing a second receptacle for a burner is provided in each case. The burners are arranged either in the first recordings or in the second recordings. Flames generated by the burners are each guided in the region between a longitudinal side wall of the furnace housing and the opposite wall of the galvanizing trough.

Furthermore, the invention relates to a method for operating a galvanizing furnace.

With the method according to the invention, the availability of the galvanizing furnace according to the invention can be increased in a surprisingly simple manner.

In this case, the invention is based on the finding that the wear of the galvanizing trough is mainly due to the high temperatures generated by the burners. It was found that in the area of the flame outlet at the respective burner, or if the galvanizing a Flammenleitblech is located immediately behind the flame outlet, the strongest wear of the galvanizing occurs, ie in this area is reducing the wall thickness of the galvanizing due to high temperatures at the highest, whereas with increasing distance to the respective burner, the wear, that is, the reduction of the wall thickness of the galvanizing trough, continuously decreases.

In the case of the galvanizing furnace according to the invention, this circumstance is taken into account by providing first receptacles for the burners not only in two diagonally opposite corner regions of the furnace housing. Rather, recordings for the burners are also provided on the two further diagonally opposite corner areas, these second recordings preferably being identical to the first recordings.

Thus, the burners, which are preferably designed as high-speed burners, can optionally be used either in the first recordings or in the second recordings.

The operation of the galvanizing furnace is then according to the invention such that the galvanizing is first operated for a predetermined period of time with the burners in the first shots. During this phase, in the area of the flame outlets, the burner, that is to say in the area of the first receptacles, experiences increased wear of the galvanizing trough, that is to say an increased reduction of the wall thickness. This wear decreases continuously along the respective side wall of the galvanizing trough in the direction of the second recordings.

After this first phase of operation, the burners are replaced, so that they are now stored in the second recordings of the furnace housing. This exchange can be carried out easily and quickly, that is without great downtime of the galvanizing furnace.

Due to the replacement of the burners, in the second phase, increased wear occurs in the areas of the galvanizing trough that connect to the flame exit areas of the burners in the second receptacles. This means that the spatial wear profile in this second phase is complementary to the spatial wear profile in the first phase.

However, this means that the replacement of the burner overall uniform wear over the entire side walls of the galvanizing is obtained.

Thus, the life of the galvanizing trough and thus the availability of the galvanizing furnace compared to a conventional operation of the galvanizing furnace are significantly increased. Namely, in a conventional operation, the burners would always be stored only in the first recordings. This would selectively lead in the first recordings associated flame outlet areas to a spatially limited strong reduction of the wall thickness of the galvanizing, so that they must be replaced in a relatively short time.

By changing the installation locations of the burner according to the invention, the life of the galvanizing trough can be significantly increased, so that the intervals in which the galvanizing trough must be replaced by a new, can be significantly increased.

In principle, the time intervals in which the galvanizing furnace is operated with burners mounted in the first recordings or in the second recordings can be specified empirically.

According to a particularly advantageous embodiment of the invention, means for location-dependent detection of the wear of the walls of the galvanizing trough are provided. Depending on the determined wear values, it is possible to change the burners from the first recordings to the second recordings or vice versa.

In this case, the time intervals in which the galvanizing furnace is operated with burners mounted in the first or in the second receptacles can be predetermined and optimized as a function of the measured wear values.

Particularly advantageous is detected as a measure of the wear of the walls of the galvanizing trough whose wall thickness.

In principle, by a corresponding number of measuring points, the wall thicknesses over the entire side walls of the galvanizing trough, along which the flames of the burners are guided, are measured.

The current wall thickness of the galvanizing trough is expediently detected in the region of the flame outlet of at least one burner. A change of the burners is then carried out when the current wall thickness falls below a predetermined limit.

This measures the wall thickness of the galvanizing trough in the most critical areas. Since the areas of highest wear limit the life of the galvanizing Wane, such a measurement is sufficient.

According to a particularly advantageous embodiment of the invention, an ultrasonic measuring head is provided for measuring the wall thickness of the galvanizing trough.

With the ultrasonic measuring head, it is possible to measure the wall thickness of the galvanizing trough during operation of the galvanizing furnace.

To carry out these measurements, closable inspection openings are advantageously provided in the longitudinal side walls of the furnace housing. For measuring the wall thickness, the ultrasonic measuring head is guided through a control opening to the outside of a wall of the galvanizing trough.

By a suitable grid of inspection openings, the location-dependent course of reducing the wall thickness of the galvanizing trough can be accurately detected.

The measurements can easily be done by just one person. For this purpose, the respective person only needs to open the closure of the desired inspection opening, in order then to guide the ultrasonic measuring head through the inspection opening into the furnace interior and then against the wall of the galvanizing trough.

Advantageously, the ultrasonic measuring head is designed as a so-called hot head, which is suitable for use at high temperatures, as in the interior of the furnace exist, is suitable. Furthermore, the ultrasonic measuring head advantageously has a magnet with which the ultrasonic measuring head can adhere to the wall of the galvanizing trough. This ensures an accurate and reproducible measurement of the wall thickness with the ultrasonic probe.

According to an expedient embodiment, the receptacles for the burners are each arranged in a frontal side wall.

As a result, a guide of the flames of the burner is ensured in the space between a longitudinal side wall of the furnace housing and a wall of the galvanizing trough in a simple manner.

According to an advantageous development, a plurality of receptacles, in each of which a burner can be arranged, are provided in each corner region of the furnace housing.

Thus, several burners can be installed in each corner area, whereby the performance of the galvanizing furnace, that is, the throughput of liquid zinc per unit time, can be increased.

Suitably, all images are identical.

This burner of the same type can be installed in any recordings of the oven housing.

Further advantageously, the recordings, in which no burner is arranged, sealed with closure means.

This ensures that the oven housing forms a sealed to the outside atmosphere unit.

According to an advantageous embodiment, the galvanizing trough has a substantially rectangular shape adapted to the cross section of the furnace housing Cross-section on. In each corner of the galvanizing trough a Flammleitblech is attached to the outer wall of the galvanizing trough.

Since the burners can be stored either in the first or second receptacles and thus can be arranged in each corner region of the furnace housing, it is accordingly expedient to protect each corner area with flame deflectors against flames from burners.

Adapted to this, control openings are provided in the longitudinal side walls of the furnace housing in such a way that the ultrasonic measuring head guided through such a control opening is guided directly against a wall of the galvanizing trough adjacent to a flame guide plate.

This can be performed by the inspection opening immediately behind the Flammleitblechen the ultrasonic probe to the wall of the galvanizing, so that a measurement at the most heavily loaded points of the galvanizing is possible.

According to an advantageous development, first temperature sensors are integrated in punches, which support a wall of the galvanizing trough against a longitudinal side wall of the furnace housing.

With these temperature sensors can thus be checked whether the stamp are exposed to high temperature loads.

Further advantageous second temperature sensors are provided for measuring the temperature in the interior of the furnace housing.

The outputs of the burners are expediently set as a function of the measured values recorded using the first or second temperature sensors.

As a result, damage to components in the interior of the oven housing can be avoided.

Figur 1:

Längsschnittdarstellung eines Ausführungsbeispiels des erfindungsgemäßen Verzinkungsofens.

Figur 2:

Querschnittdarstellung des Verzinkungsofens gemäß Figur 1.

The invention will be explained below with reference to the drawings. Show it:

FIG. 1:

Longitudinal view of an embodiment of the galvanizing furnace according to the invention.

FIG. 2:

Cross-sectional view of the galvanizing furnace according to FIG. 1 ,

The FIGS. 1 and 2 The galvanizing furnace 1 has a furnace housing 2 with a rectangular contour having bottom 3 and two perpendicularly projecting from the bottom 3 longitudinal side walls 4 and end side walls 5, wherein the two end-side side walls 5 opposite and the longitudinal side Side walls 4 are arranged opposite one another. The oven housing 2 thus has a constant over its entire height rectangular cross-section.

In the interior of the furnace housing 2 is a galvanizing trough 6, which serves to receive liquid zinc to be heated. The galvanizing trough 6 has a substantially rectangular cross section adapted to the cross section of the furnace housing 2, so that the side walls 7 of the galvanizing trough 6 are arranged at a constant distance from the longitudinal side walls 4 and end side walls 5 of the furnace housing 2. The galvanizing trough 6 has a flat trough bottom 8, which rests on the bottom 3 of the furnace housing 2.

The upper edge of the galvanizing trough 6 is received in an edge segment 9 of the oven housing 2 extending on the upper sides of the longitudinal side walls 4 and the front side walls 5. The open top of the galvanizing trough 6 can be closed with a cover, not shown.

The galvanizing trough 6 is supported with punches 10 against the inner sides of the longitudinal side walls 4 of the furnace housing 2. The stamp 10 form thus a clamping frame for fixing the position of the galvanizing trough 6 in the furnace housing 2.

At a front side wall 5, a flue gas outlet opens, which is formed in the form of a flange 11 with an exhaust flap 11a. Via the exhaust flap 11 a, the room pressure of the furnace atmosphere is controlled in order to obtain an effective transition of the temperature to the galvanizing trough 6.

In or on the punches 10, first temperature sensors 12 are provided with which the temperatures in the punches 10 themselves can be measured. This can be controlled overheating of the punch 10.

Furthermore, located in the region of the inner sides of the side walls 7 second temperature sensors 13, with which the temperature in the interior of the oven housing 2 is measured.

The first and second temperature sensors 12, 13 are advantageously formed by thermocouples. Depending on the measured values generated with the temperature sensors 12, 13, the heating power of the galvanizing furnace 1 and thus the temperature in the interior of the furnace housing 2 can be controlled.

The heating of the interior of the furnace housing 2 by means of burners. The burners are designed as gas burners, in the present case as high-speed burners 14.

For storage of the high-speed burners 14 according to the invention in two diagonally opposite corner regions of the furnace housing 2 in the respective end-side side wall 5 first receptacles 15 incorporated. Furthermore, in the two further diagonally opposite corner regions of the oven housing 2, second receptacles 16 are incorporated into the respective end-side side wall 5.

The first and second receptacles 15, 16 are of identical design and adapted to the size of the high-speed burners 14, so that the high-speed burners 14 can optionally be installed in first or second receptacles 15, 16.

FIG. 2 shows in each corner region a receptacle 15, 16. Generally, in each corner area a plurality of identical first recordings 15 or second recordings 16 can be arranged at a distance one above the other, so that in each of these recordings 15, 16 of a corner region, a high-speed burner 14 can be stored.

According to the invention, the high-speed burners 14 are used either only in the first receptacles 15 or in the second receptacles 16 so as to heat the interior of the furnace housing 2.

Since the installation of high-speed burners 14 in each corner region of the oven housing 2 is possible, like the FIGS. 1 and 2 show, the outer walls of the galvanizing trough 6 at all corners covered with Flammenleitblechen 17, so as to protect the walls of the galvanizing trough 6 against the flames occurring at the high-speed burners 14. The identically formed flame guide plates 17 extend over the entire height of the galvanizing trough 6.

In the in FIG. 2 As shown, the high-speed burners 14 are arranged in the first receptacles 15. The second receptacles 16, in which no high-speed burners 14 are located, are tightly closed with closure means 18, so that the furnace walls are tightly gekappselt. The closure means 18 may each be formed by Ofenisoliermaterial and a cover plate.

If the galvanizing furnace 1 with the burner configuration according to FIG. 2 operated, the flames of the high-speed burner 14 in the interstices each of a longitudinal side wall 4 of the oven housing second and a wall of the galvanizing trough 6, whereby the liquid zinc in the trough is heated.

According to the type of installation of the high-speed burners 14 in the first seats 15, the flame temperature in the exit area of the high-speed burner 14 (in FIG FIG. 2 labeled A) and increases to the area at the other end of the furnace housing 2 (in FIG FIG. 2 denoted by B) continuously.

Accordingly, during operation of the galvanizing furnace 1 with the burner configuration occurs FIG. 2 in the area A, the highest wear of the galvanizing trough 6, wherein the wear consists in a reduction of the wall thickness of the galvanizing trough 6. The reduction of the wall thickness then decreases continuously from area A to area B.

The wear-related reduction of the wall thickness is detected by measurement during operation of the galvanizing furnace 1, preferably within regular time intervals.

For this purpose, identical arrangements of control openings 19 are incorporated in the longitudinal side walls 4 of the furnace housing 2, which can be closed with covers not shown separately.

To carry out a non-contact measurement of the wall thickness of the galvanizing trough 6 during operation of the galvanizing furnace 1, not shown ultrasonic measuring heads are provided. To carry out such a measurement, the cover is removed at a control opening 19, and then the ultrasonic measuring head is guided through the inspection opening 19 to the wall of the galvanizing trough 6, where the ultrasonic measuring head preferably adheres to the wall of the galvanizing trough 6 by means of an integrated magnet in a defined measuring position.

How out FIG. 1 can be seen, four rows of control openings 19, each with three superimposed control openings 19 are provided. The two outer rows are arranged immediately after the Flammleitbleche 17. Furthermore, two central rows of control openings 19 are provided.

By guiding ultrasonic measuring heads through the inspection openings 19, the wall thickness of the galvanizing trough 6 can be detected in a spatially resolved manner during the operation of the galvanizing furnace 1. In particular, by guiding the ultrasonic measuring heads through the left row of inspection openings 19, the wall thickness of the galvanizing trough 6 in the area A, where the greatest wear of the galvanizing trough 6 impinges, can be measured.

In particular, if it is determined in this critical area A that the wall thickness of the galvanizing trough 6 has dropped below a critical value, preferably at the next maintenance period of the galvanizing furnace 1, an exchange of attachment locations of the high-speed burners 14 made such that the high-speed burners 14 from the first recordings 15 expanded and now installed in the second 16 shots. Accordingly, the first receptacles 15 are then closed with the closure means 18.

Since in the subsequent operation of the galvanizing furnace 1, the high-speed burners 14 are now installed in the second receptacles 16, now the areas B are the highest wear. The areas A, which are still subject to high stress during the first operating phase, are protected, since the flame temperatures of the high-speed burners 14 are lower there. Thus, despite the occurrence of the first phase of heavy wear in the galvanizing pan 6 in the areas A galvanizing furnace 1 continue to operate without the risk of damage, as in the second phase arranged in the second receptacles 16 high-speed burners 14 in the areas A only a slight wear occurs. This can be the Galvanizing furnace 1 as long as continue to operate without risk of damage to the galvanizing pan until even in the areas B, a reduction in the wall thickness of the galvanizing trough 6 occurs up to the limit. The control of the wall thickness of the galvanizing trough 6 takes place again by measurements carried out with the Umschaltmessköpfen. Thus, the service life of the galvanizing furnace 1 with the galvanizing trough 6 is significantly increased compared to an operation in which the high-speed burners 14 are permanently arranged only in the first receptacles 15.

LIST OF REFERENCE NUMBERS

(1)

galvanizing

(2)

furnace housing

(3)

ground

(4)

longitudinal side wall

(5)

front side wall

(6)

Verzinkungswanne

(7)

Side wall

(8th)

Wannenboden

(9)

edge segment

(10)

stamp

(11)

flange

(11a)

exhaust flap

(12)

first temperature sensor

(13)

second temperature sensor

(14)

High-speed burners

(15)

first recording

(16)

second shot

(17)

Flammleitblech

(18)

closure means

(19)

inspection hole

Claims (15)

Galvanizing furnace (1) having a galvanizing trough (6) and a furnace housing (2) enclosing the galvanizing trough (6), which has a rectangular cross section, wherein the furnace housing (2) has two opposite longitudinal side walls (4) and two opposite front side walls (5). characterized in that in the areas of two diagonally opposite corners of the furnace housing (2) in each case at least one first receptacle (15) is provided for a burner that in the A second receptacle (16) is provided for a burner areas of the two other diagonally opposite corners of the oven housing (2) and that optionally burners are arranged either in the first receptacles (15) or in the second receptacles (16), wherein the flames generated in the burners in each case in the region between a longitudinal side wall (4) of the furnace housing (2 ) and the opposite wall of the galvanizing trough (6) are guided. Galvanizing furnace according to claim 1, characterized in that means for location-dependent detection of the wear of the walls of the galvanizing trough (6) are provided, and that, depending on the determined wear values, a change of the burners from the first receptacles (15) to the second receptacles (16). or vice versa is feasible. Galvanizing furnace according to one of claims 1 or 2, characterized in that as a measure of the wear of the walls of the galvanizing trough (6) whose wall thickness is detected. Galvanizing furnace according to one of claims 1 to 3, characterized in that in the region of the flame outlet of at least one burner, the current wall thickness of the galvanizing trough (6) is detected, and that a change of the burner is carried out when the current wall thickness falls below a predetermined limit. Galvanizing furnace according to one of claims 1 to 4, characterized in that an ultrasonic measuring head is provided for measuring the wall thickness of the galvanizing trough (6). Galvanizing furnace according to claim 5, characterized in that closable control openings (19) are provided in the longitudinal side walls (4) of the oven housing (2), wherein for measuring the wall thickness of the ultrasonic measuring head through a control opening (19) to the outside of a wall of the galvanizing trough (6 ) is guided. Galvanizing furnace according to one of claims 1 to 6, characterized in that the receptacles (15, 16) for the burners are each arranged in a frontal side wall (5), and / or that in each corner region of the furnace housing (2) a plurality of receptacles (15 , 16), in each of which a burner can be arranged, are provided. Galvanizing furnace according to one of claims 1 to 7, characterized in that all receptacles (15, 16) are identical. Galvanizing furnace according to one of claims 1 to 8, characterized in that the receptacles (15, 16), in which no burner is arranged, with sealing means (18) are sealed. Galvanizing furnace according to one of claims 1 to 9, characterized in that the burners are formed by high-speed burners (14). Galvanizing furnace according to one of Claims 1 to 10, characterized in that the galvanizing trough (6) has a substantially rectangular cross section adapted to the cross section of the furnace housing (2), and in each corner region of the galvanizing trough (6) a flame guide plate (17). is attached to the outer wall of the galvanizing trough (6). Galvanizing furnace according to claim 11, characterized in that control openings (19) are provided in the longitudinal side walls (4) of the furnace housing (2) such that the ultrasonic measuring head guided through such a control opening (19) adjoins directly against a flame guide plate (17) Wall of the galvanizing trough (6) is guided. Galvanizing furnace according to one of claims 1 to 12, characterized in that first temperature sensors (12) are integrated in dies (10) which support a wall of the galvanizing trough (6) against a longitudinal side wall (4) of the furnace housing (2), and / or that second temperature sensors (13) for measuring the temperature in the interior of the furnace housing (2) are provided. Galvanizing furnace according to claim 13, characterized in that the outputs of the burners are adjusted as a function of the measured values acquired with the first or second temperature sensors (12, 13). Method for operating a galvanizing furnace (1) having a galvanizing trough (6) and a furnace housing (2) enclosing the galvanizing trough (6), which has a rectangular cross section, wherein the furnace housing (2) has two opposite longitudinal side walls (4) and two opposite end faces Having side walls (5), and with burners for heating liquid zinc in the galvanizing trough (6), characterized in that in the regions of two diagonally opposite corners of the furnace housing (2) in each case at least one a first receptacle (15) is provided for a burner, that in each case a second receptacle (16) is provided for a burner in the areas of the two other diagonally opposite corners of the oven housing (2), and that either burner in either the first receptacles (15 ) or in the second receptacles (16), wherein flames produced by the burners are respectively guided in the region between a longitudinal side wall (4) of the furnace housing (2) and the opposite wall of the galvanizing trough (6).

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