EP3612658B1 - Hot dip galvanizing device and method - Google Patents

Description

The present invention relates to the technical field of galvanizing iron-based or iron-containing components, in particular steel-based or steel-containing components (steel components) or components, preferably for the automobile or motor vehicle industry, but also for other technical areas of application (e.g. for the construction industry, the area of general mechanical engineering, the electrical industry, etc.), by means of hot-dip galvanizing (hot-dip galvanizing).

In particular, the present invention relates to a device for hot-dip galvanizing, also known as a hot-dip connection, of components with a galvanizing kettle for receiving a zinc melt in a boiler interior formed by a wall of the galvanizing kettle, as well as a method for hot-dip galvanizing components using an aforementioned device for hot-dip galvanizing components.

Hot-dip galvanizing is understood to be a process which protects iron-based or iron-containing or steel-based or steel-containing components from corrosion, in particular rust. In the case of hot-dip galvanizing, a metallic zinc coating is applied to the surface of the iron or steel-containing component by immersion in a hot, liquid zinc melt. A resistant alloy layer consisting primarily of iron and zinc is formed on the surface of the component after galvanizing and a very firmly adhering, pure zinc layer is arranged over this alloy layer. Hot-dip galvanizing is one of various galvanizing methods.

On the process side, a distinction is made in hot-dip galvanizing between discontinuous piece galvanizing of components and continuous strip galvanizing of, for example, sheet steel or wire. Both batch galvanizing and strip galvanizing are standardized or standardized processes, cf. B. the standards DIN EN ISO 1461 for batch galvanizing or DIN EN 10143 and DIN EN 10346 for strip galvanizing. In the case of strip galvanizing, the strip galvanized steel is a preliminary or intermediate semi-finished product, which is further processed after galvanizing, in particular by forming, punching, cutting, etc. Batch galvanizing, on the other hand, uses completely manufactured or shaped components, which are only hot-dip galvanized after production and thus protected against corrosion.

For hot-dip galvanizing, the zinc melt must be kept in a hot liquid state so that solidification of the zinc melt in the hot-dip galvanizing kettle is avoided. The temperature of the zinc melt lies approximately in a temperature range of 440 ° C to 460 ° C. This temperature range results on the one hand from the melting point of zinc at 419.5 ° C and on the other hand from processing aspects. When hot-dip galvanizing with zinc alloys, e.g. B. zinc-aluminum melts and / or a special process management, z. B. in high-temperature galvanizing, the operating temperature of the zinc melt can also be above the aforementioned temperature range.

The disadvantage of all hot-dip galvanizing processes and hot-dip galvanizing plants is that the zinc melt continuously loses heat, both via radiation losses and via the zinc bath surface and the boiler walls. Furthermore, temperature fluctuations occur due to the immersion of relatively cold items to be galvanized, for example iron-containing components, which causes the melt to cool down locally. In order to compensate for the occurring heat losses and to keep the zinc melt molten during the hot-dip galvanizing operation in the aforementioned temperature range, so that the iron components that are immersed in the zinc melt can react with the zinc melt and accordingly a thin zinc layer is formed on the component surface, the galvanizing kettle must continuously heated. This is usually done by indirect heating of the galvanizing boiler from the outside, essentially via the burner devices using gas burners. In addition to the burner device, the introduction of heat into the melt by the hot-dip galvanizing kettle with other, alternative, different energy sources is conceivable. To compensate for heat losses, the temperature on the outside of the wall of the galvanizing kettle is greater than the target temperature of the zinc melt or the temperature of the zinc melt in the interior of the galvanizing kettle. The galvanizing kettle is subject to permanent global thermal stress, which is also characterized by a temperature gradient across the wall thickness. In addition, the galvanizing kettle is subject to mechanical stress caused by the static pressure of the zinc melt.

Galvanizing kettles are usually set in special ovens in which the heating devices are installed.

In addition, the hot-dip galvanizing kettles are mostly designed as steel kettles or as kettles with special sheets and / or special coatings with a thickness of at least essentially 50 mm. On the inner walls of the hot-dip galvanizing kettle, the attack or the reaction of the molten zinc with the non-inert migration material results in material removal from the kettle wall, which thus causes a reduction in the kettle wall thickness. This removal of the boiler wall thickness is undesirable, but cannot be avoided in the prior art, so that there is a gradual removal of the wall thickness over the useful life of the galvanizing boiler. The speed of the removal depends on a variety of factors, for example the throughput, the zinc melt temperature, the boiler wall temperature and the frequency and amplitude of the temperature fluctuations caused by the immersion of the ferrous components in the zinc melt.

A large wall thickness can be selected to ensure the longest possible operating life and / or service life of the boiler with simultaneously high throughput rates and low procurement and operating costs. It is important to ensure that the wall thickness does not fall below a minimum. If the wall thickness is too small, a boiler breakthrough or a boiler failure can occur, with a boiler failure causing very high costs. These high costs arise from production stoppages, zinc losses, repair costs for zinc recovery, especially in the event of an average, and possibly a replacement investment. If the wall thickness of the galvanizing kettle is too small, this may result in a local and / or global loss of stability of the galvanizing kettle. In the event of a local loss of stability of the galvanizing kettle, a leak can lead to the leakage of the hot liquid zinc melt, which results in very high economic damage, a greatly increased operational risk and a risk to occupational safety for the galvanizing company. In addition, in the event of a global loss of stability, a possible severe deformation of the boiler is caused, with a boiler change being made more difficult when the boiler is deformed and consequently considerable delays occur in the boiler replacement. In order to avoid the aforementioned problems, galvanizing kettles are replaced by a new kettle relatively early in practice. The replacement interval is based on empirical values, where it is assumed that the boiler wall is removed slowly and evenly, in particular at around 2 to 3 mm per year.

Increased local abrasion and thus a possible local loss of stability of the galvanizing kettle can occur as a result of permanent and / or temporary misalignment of a burner. Accordingly, increased boiler wear is usually due to improper galvanizing operation. An improper galvanizing operation cannot always be recognized and avoided by the galvanizer, so that the galvanizing kettle is exposed to increased thermal and / or mechanical stress in some places. This load and the associated accelerated erosion can be caused, among other things, by an incorrect setting of the burner and by an incorrect arrangement of the heat input zone, i. H. the zone on which the burner acts may be conditional.

In order to avoid the local and / or global loss of stability of the galvanizing kettle, the galvanizing kettle is, as already mentioned, exchanged by means of a corresponding risk management system with defined minimum wall thicknesses. When the galvanizing kettle is replaced, the contents of the kettle - the hot molten zinc - is pumped out and a new kettle is inserted into the melting furnace, after which the molten zinc that has in the meantime remained molten is pumped back again. This replacement not only leads to a standstill, but also leads to increased costs for the new purchase of the boiler and for the time-consuming replacement of the galvanizing boiler.

The DE 36 22 106 A1 relates to a method for measuring the wall thickness of a container which contains a hot zinc melt, which deposits a hard zinc layer on the container wall and into which an ultrasonic measuring probe is immersed, the inner surface of the hard zinc layer being mechanically removed before the measurement until a Thickness measurement sufficient echo of the ultrasound is received.

Furthermore, the NL 7209733 A a device and a corresponding method for measuring the wall thickness of a molten zinc boiler, wherein one or more ultrasonic probes are introduced into the outer wall of the molten zinc boiler via bores, each bore being located near the heat input zone of a burner; the zinc smelting kettle is surrounded by an outer vessel, the measuring probes being provided in the space, whereby the ultrasonic measurement is intended to provide a conclusion about the wall of the galvanizing vessel.

It also affects the DE 1 220 086 B a device for indicating incipient and complete melting crucible breakthroughs, especially in induction furnaces, the device consisting of at least one axially supported jacket electrode embedded in the insulation between the outer wall of the crucible and the induction coil, which is in conductive connection with the inside of the crucible via a voltage source through a display instrument , with the jacket electrode being subdivided along the entire circumference in the edge area of the induction coil and with the jacket electrode ultimately measuring whether a boiler breakthrough takes place.

The DE 20 2013 105 789 U1 relates to a melting furnace, in particular a hot-dip galvanizing furnace, with a boiler designed for immersion treatment in a melt, in particular zinc melt, a burner unit acting on an outer surface of the boiler for heating the boiler and a control unit controlling the burner unit for monitoring and regulating the temperature of the melt, the Burner unit has at least two independently controllable burners acting on spaced apart heat input areas of the outer surface of the boiler and the control unit has a temperature measuring unit for contactless measurement of the temperature of the heat input areas.

The object of the present invention is now to avoid or at least largely reduce the disadvantages in the prior art.

In particular, it is the object of the invention to provide a device for hot-dip galvanizing or a method which avoids a boiler failure, in particular due to a local and / or global loss of stability of the galvanizing boiler.

In particular, it is the object of the present invention to enable efficient and safe use of the galvanizing kettle.

To solve the problem described above, the present invention proposes - according to a first aspect of the present invention - a device for hot-dip galvanizing according to claim 1; further, in particular special and / or advantageous configurations of the device according to the invention are the subject of the related device subclaims.

The present invention further relates - according to a second aspect of the present invention - to a method for hot-dip galvanizing according to the relevant independent method claim; further, in particular special and / or advantageous embodiments of the method according to the invention are the subject matter of the related method subclaims.

It goes without saying in the following statements that configurations, embodiments, advantages and the like, which are explained below for the purpose of avoiding repetitions only for one aspect of the invention, of course also apply accordingly with regard to the other aspects of the invention, without this being a separate one Mention is required.

With all of the relative or percentage weight-related information mentioned below, in particular relative amounts or weight information, it should also be noted that these are to be selected by the person skilled in the art within the scope of the present invention in such a way that they are in total including all components or ingredients, in particular as defined below, always add or add to 100% or 100% by weight; but this goes without saying for the expert.

In addition, it applies that the person skilled in the art - depending on the application or on a case-by-case basis - can, if necessary, deviate from the range information given below without departing from the scope of the present invention.

In addition, all of the values or parameters or the like mentioned below can in principle be determined or determined using standardized or standardized or explicitly stated determination methods or otherwise with determination or measurement methods known per se to the person skilled in the art.

Having said that, the present invention will now be explained in detail below.

The subject of the present invention - according to a first aspect of the present invention - is thus a device for hot-dip galvanizing of components with a galvanizing kettle for receiving a zinc melt in a kettle interior formed by a wall of the galvanizing kettle, a monitoring device for monitoring the wall thickness of the wall of the galvanizing kettle during of the galvanizing plant is provided, the monitoring device having at least one sensor provided in the area of the outside of the wall of the galvanizing kettle for measuring at least the temperature of the galvanizing kettle and an evaluation device coupled to the sensor for processing the measured value recorded by the sensor and calculating and / or deriving the wall thickness .

In this context, the galvanizing operation is understood not only to mean the immersion of a component in a galvanizing kettle, but also that the hot liquid zinc melt must be kept in a hot liquid state, whereby, for this purpose, heat is always, in particular continuously, in the galvanizing kettle via the wall of the galvanizing kettle the zinc melt is introduced.

In connection with investigations that were carried out in advance of the invention, it was first established that the galvanizing kettle, when it has been replaced, only reaches a critical thickness in one or a few places, so that a large part of the kettle still continues would have been usable. However, since it is not the average but rather the minimum wall thickness that is decisive with regard to occupational safety and / or operational safety, it has been considered necessary to replace the galvanizing kettle in this state as well. The automatic monitoring according to the invention now makes it possible to monitor the condition of the thickness of the boiler wall more precisely and also to better control the galvanizing process, so that the economic disadvantages that previously resulted from a regular replacement of a galvanizing boiler can be avoided.

An automatic monitoring of the wall thickness of the wall of the galvanizing vessel offers various advantages according to the invention. In this way, both global and local stability losses of the boiler can be avoided or at least largely reduced, which results in both an increase in work and operational safety and a reduction in operating and production costs. The galvanizing kettle can be used purposefully and purposefully by the monitoring device, whereby it can always be ensured that the galvanizing kettle does not reach a critical wall thickness that would make it necessary to replace the galvanizing kettle. In particular, due to a continuous and / or area measurement by means of the monitoring device of the wall thickness, increased, in particular local, removal rates, for example at thermally induced "hotspots", can be detected early, so that a local loss of stability of the galvanizing kettle can be avoided.

Due to the continuous measurement of the boiler wall thickness, the invention enables precise and reliable monitoring of the wall or the wall thickness as well as individual, defined or all wall areas of the boiler. Due to the removal of the wall thickness that is recorded in this way, the system safety is increased and thus a greater utilization of the material is possible without loss of safety. The minimum wall thickness to be kept can therefore be reduced, since the wall thickness of the galvanizing vessel no longer has to be estimated, but is instead measured purposefully. It goes without saying that the measurement or determination of the boiler wall thickness can also take place indirectly according to the invention, so that the boiler wall thickness can be derived from other characteristic values.

The monitoring device according to the invention results in an increased service life of the galvanizing kettle, since the replacement of the galvanizing kettle now does not have to take place at predetermined intervals, but is carried out in a targeted manner as and when required. This results in a more efficient use of the galvanizing kettle, in particular with the monitoring device offering the possibility of not only recognizing local and / or global stability losses, but also counteracting them. This results in an optimized, even and reduced wall removal of the galvanizing vessel.

In addition, the monitoring device can be retrofitted to existing galvanizing devices or to existing galvanizing tanks. The effort involved in this regard is low, especially taking into account the resulting essential advantages.

As stated above, in the device according to the invention the monitoring device has at least one sensor provided in the area of the outside of the wall of the galvanizing kettle for measuring at least the temperature of the galvanizing kettle. In this context, the sensor, for example, a detector, measuring transducer and / or measuring sensor is regarded as a sensor, the sensor being a technical component being able to detect both physical and chemical properties or characteristic values. These characteristic values are recorded by means of a physical and / or chemical effect and then converted into an electrical signal, in particular for later processing.

According to the invention, the sensor is coupled to an evaluation device for processing the measured value recorded by the sensor, in particular the characteristic value and, preferably, further recorded characteristic values, and for calculating and / or deriving the wall thickness, preferably by means of the measured value and / or characteristic value. By recording the measured value by the sensor or the converted characteristic value, conclusions can be drawn about the wall thickness of the galvanizing vessel, which enables the galvanizer to react with regard to the wall thickness of the wall.

According to the invention, it is advisable to arrange the sensor (s) and the associated measurement technology in such a way that they are subject to little wear and tear and are otherwise easily accessible so that maintenance, inspection and / or repair of the monitoring device can be carried out easily and easily. In principle, it goes without saying in this context that the galvanizing kettle can have a multilayer structure, whereby it can preferably also have an outer kettle. It is advisable here for the sensor or sensors to be arranged between the actual galvanizing kettle and the outer kettle. The outer kettle advantageously protects the inner kettle of the galvanizing kettle. As a result, the additional protection of the outer boiler can provide further protection for the sensor, which accordingly preferably no longer directly faces a burner device or the furnace structure. In addition, the outside boiler is also advantageous in that, in the event of a leak in the inner galvanizing vessel, it prevents the hot liquid zinc melt from escaping into the area of the furnace structure.

In this context, it goes without saying that the sensors are preferably designed so that they can withstand thermal loads at temperatures of over 450 ° C., preferably between 450 ° C. to 1000 ° C., more preferably between 550 ° C. to 850 ° C. and in particular at least can withstand essentially between 550 ° C to 700 ° C. This thermal load on the sensor results in particular from the fact that the sensor is preferably arranged in the area of the outside of the wall of the galvanizing boiler, so that it is exposed to the thermal load due to a burner device that generates the required heat or the required energy input into the area of the interior of the boiler Ensures the zinc melt withstands. A sensor that is designed in this way can be used specifically for temperature detection in the area of the wall of the galvanizing kettle. As a result, there is an increased service life or service life of the sensor, so that frequent replacement of the sensor due to thermal loads can be avoided and, consequently, there is a reduction in operating costs.

Furthermore, in an advantageous embodiment of the inventive concept, it is provided that the monitoring device is designed in such a way that measured value acquisition can take place continuously. Continuous recording of measured values is understood to mean recording the characteristic values for determining the wall thickness of the wall of the galvanizing vessel at predetermined, usually regular time intervals. The time intervals between the recorded or measured characteristic values are in particular adapted to the existing operating situation and preferably to the component throughput. The intervals between the recordings for the measured values are preferably to be selected to be at least essentially constant, whereby a continuous monitoring of the wall thickness can preferably be ensured. A minute and / or hourly measurement value recording can advantageously take place.

In addition, in a particularly preferred embodiment it is provided that at least one further sensor is provided for measuring at least one measured value of the device for hot-dip galvanizing, in particular the burner space and / or the boiler interior and / or the zinc melt. Preferably is the further sensor, in particular analogous to the sensor of the measured value of the galvanizing kettle, coupled to the evaluation device, in particular the evaluation device processing the measured value recorded by the further sensor and for calculating and / or deriving the wall thickness of the wall of the galvanizing kettle, in particular using that recorded by the sensor Measured value, uses. The further sensor and / or the further sensors can record, for example, the temperature of the zinc melt and / or the temperature in the burner space and use them to later calculate the wall thickness of the wall of the galvanizing vessel. In this context, it goes without saying that a plurality of further sensors for measuring measured values of the device for hot-dip galvanizing can be provided. With regard to the number of measuring points for the other sensors for the burner chamber and zinc melt temperatures and the accuracy of the detection, due to the air volume in the burner chamber and the zinc melt volume in the interior of the galvanizing boiler, it can be assumed with sufficient accuracy that a homogeneous temperature distribution in the air or in the zinc melt is present and measurement value acquisition at comparatively few points, in particular at least two points and preferably less than twenty measuring points, is sufficient.

Incidentally, in a further preferred embodiment, the galvanizing kettle surrounds the support structure of a furnace, which means that the galvanizing kettle is arranged inside a galvanizing furnace. The sensor, in particular designed as a temperature sensor, is preferably arranged in the region of the boundary surface of the wall of the galvanizing vessel, in particular in the region of the outer wall of the galvanizing vessel. The sensor is further preferably placed at least in some areas on the outside of the wall of the galvanizing kettle. This arrangement enables the walls of the galvanizing kettle to be monitored continuously.

According to a further preferred embodiment of the device according to the invention, the sensor is designed as a thin-film thermocouple and / or as a jacket thermocouple. The sensors, as already shown above, and the cabling belonging to the sensors are preferably designed in such a way that they withstand high temperature loads, in particular at temperatures in the range from 400 ° C. to 700 ° C., as well as the wall pressure of the galvanizing kettle. For these loads, thin-film thermocouples are particularly suitable, which are directly on the outside of the wall of the galvanizing kettle or can be applied or attached in this area. As an alternative or in addition, other suitable sensors, such as, for example, sheathed thermocouples, which are designed for a high temperature load, can also be used. The thin-film thermocouples are particularly suitable for high-precision temperature measurement on surfaces in demanding, versatile applications. The thin-film thermocouples are preferably designed to be small, light, thin and / or flexible and have fast response times. In addition, they are also advantageously designed to be robust. The response times of the thin-film thermocouples are preferably provided in the millisecond range. Sheathed thermocouples are characterized in particular by their slight flexibility and their high resistance to high temperature loads. In addition, they preferably have mechanical insensitivity and a short response time.

In addition, in a special embodiment of the device according to the invention, a plurality of sensors distributed over an area of the outside of the wall of the galvanizing vessel is provided. A plurality of sensors is preferably arranged in the interface of the wall of the galvanizing vessel. The expression "boundary surface of the wall" denotes, on the one hand, the outside of the wall itself, with the sensors being attached directly to the wall. However, the boundary surface of the wall also means an area, in particular an area immediately adjacent to the wall. In this case, the sensors are not in direct contact with the wall of the galvanizing kettle. So you are in an adjacent area. The sensors are then not attached to the wall, but by other means, which will be discussed in more detail below. The sensors preferably have direct contact with the wall or are in direct contact with it. The sensors or the sensor can be attached to the outside of the wall of the galvanizing vessel and / or the sensor and / or the sensors are in contact with the wall of the galvanizing vessel.

A continuous measurement in connection with a possible two-dimensional measurement based on a plurality of sensors enables thermal hotspots, in particular local stability losses, to be detected at an early stage, so that these thermal hotspots can be avoided by suitable countermeasures , Removal of the boiler wall thickness results. Additionally is Redundancy of the monitoring device is guaranteed by a plurality of sensors, since the other sensors can continue to guarantee the continuous recording of measured values even if one sensor fails. A redundant monitoring device increases failure, functional and operational safety. A plurality of sensors not only ensures redundancy of the monitoring device, but also covers a large area of the wall of the galvanizing vessel.

In connection with the present invention, it is also preferred that at least the areas of the galvanizing kettle which are directly exposed to the burner device are detected by sensors. In particular, it is provided that at least 20%, in particular more than 40% and particularly preferably more than 60% of the outside of the wall of the galvanizing kettle are detected by sensors and it goes without saying that the aforementioned kettle area relates to the area of the galvanizing kettle that is usually filled with the hot liquid melt. The upper area of the galvanizing kettle, in which there is usually no melt, is accordingly irrelevant and is also not monitored. In practice, usually only the upper 5 to 10 cm of the galvanizing kettle are not filled with the hot liquid melt, so that, preferably, the wall thickness of the galvanizing kettle is monitored over the entire area that is in contact with the hot molten zinc.

Although it is basically possible to arrange and fasten the sensor (s) directly on the outside of the wall of the galvanizing process, in a preferred embodiment of the invention it is provided that the sensor and / or the plurality of sensors at one, in particular over the entire height of the galvanizing kettle and / or a carrier plate extending over a defined area, in particular wherein the sensors have direct and / or immediate contact with the outside of the wall of the galvanizing kettle through the carrier plate. The sensors can also preferably be embedded in the carrier plate, so that in particular a direct arrangement on the galvanizing vessel wall results. The sensors are additionally protected by the carrier plate and / or the carrier plate, since the carrier plate is arranged in particular between a burner device having at least one burner and the galvanizing boiler wall, in particular with the sensors or the sensor facing the side of the galvanizing boiler facing away from the burner device are / is. The temperature is thus preferably recorded by means of the sensor between the carrier plate or the carrier plate and the wall of the galvanizing kettle, in particular in the boundary surface of the wall, in particular wherein the wall thickness of the galvanizing kettle can be deduced from a correlative relationship between the temperature and the wall thickness or the wall thickness can be derived or calculated by means of the temperature.

It is further preferred that the carrier plate with the sensor or the sensors is to be attached to the outside of the galvanizing vessel wall in such a way that a full-surface, in particular uninterrupted, contact with the wall of the galvanizing vessel is established. The carrier plate is preferably screwed to the galvanizing vessel wall. When the carrier plate is screwed to the boiler wall, the boiler wall is preferably designed in advance in such a way that weld studs with threads are placed on it. In particular, this embodiment variant results in low costs, both for production and for assembly. The carrier plate having the sensor or the sensors does not have to assume any static load-bearing effect, in particular for the galvanizing kettle, so that the carrier plate or the carrier plate can preferably be made relatively thin. In addition, the result is that the carrier plate can be attached quickly and easily to the outside of the galvanizing kettle, in particular before it is lifted into the supporting structure of the furnace, so that the assembly effort and the associated downtime of the galvanizing kettle can be minimized.

mit: • Temperaturfeld T = T (x, y, z, τ) [T] = K • Wärmeleitfähigkeit λ = λ (T, p) $$\left[\lambda \right]=\frac{W}{\mathit{mK}}$$

• Flächenelement, durch welche die Wärme strömt A [A] = m ² • Wärmeleistung / Wärmestrom $\overrightarrow{\dot{Q}}$

[Q̇] = W The idea on which the aforementioned embodiment is based is that, by means of the temperature in the space between the carrier plate and the galvanizing vessel wall, in particular by means of the temperature of the boundary surface of the wall, the wall thickness of the galvanizing vessel can be inferred or calculated, in particular on the basis of the first Fourier's Equation. The first Fourier equation describes the heat output Q̇ transferred by heat conduction, also called heat diffusion or conduction or heat flow. The heat output is understood as the heat flow in a solid and / or a fluid at rest as a result of the influence of temperature. The heat flows - according to the second law of thermodynamics - always in the direction of the lower temperature. Due to the law of conservation of energy, no thermal energy can be lost. The conduction of heat is the diffusion of thermal energy, with one Temperature field T ( x, y, z, τ ) can be written vectorially according to the first Fourier's law as: $$\overrightarrow{\dot{Q}}=-\lambda \cdot \mathrm{A.}\cdot \overrightarrow{\nabla }\cdot T$$

With: • Temperature field T = T ( x , y , z , τ ) [ T ] = K • thermal conductivity λ = λ ( T, p ) $$\left[\lambda \right]=\frac{\mathrm{W.}}{\mathit{mK}}$$

• Surface element through which the heat flows A [ A ] = m ² • Heat output / heat flow $\overrightarrow{\dot{Q}}$

[ Q̇ ] = W

Assuming an isotropic material is present, λ can be taken as a scalar. The differential results: $${\dot{Q}}_i=-\lambda \cdot \mathrm{A.}\frac{\partial T}{\partial x_i}$$

In the non-isotropic case, the following applies in differential notation: $$\frac{{\dot{Q}}_i}{\mathrm{A.}}=-{\lambda }_{\mathit{ij}}\cdot \frac{\partial T}{\partial x_j}$$

As a special case, in particular for the simple calculation of the wall thickness, a stationary heat output, also called heat flow and / or heat flow, can be assumed, where τ in this case represents the time. $$\begin{array}{l}\frac{d\dot{Q}}{\mathit{d\tau }}=0\\ \stackrel{\mathrm{.}}{\mathrm{Q}}=\mathrm{const}.\end{array}$$

Consequently, equation (1) can be simplified with (4) in the one-dimensional case $$\stackrel{.}{\mathrm{Q}}=-\lambda \cdot \mathrm{A.}\frac{\mathit{dT}}{\mathit{dx}}=\mathit{const}.$$

Integration results in a first system with thermal conductivity λ ₁ , with a flat plate having a thickness t ₁ and temperature T ₁ on one side and temperature T ₂ on the other side of the flat plate, that: $$\begin{array}{l}\begin{array}{cc}\frac{\stackrel{.}{\mathrm{Q}}}{{\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1{\mathrm{A.}}_1}={\displaystyle \underset{0}{\overset{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}{\int }}\mathit{dx}=-{\displaystyle \underset{T_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2}{\int }}\mathit{<figure-callout\; id="1"\; label="German\; \lambda "\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">German</figure-callout>}}}& {\lambda }_{}{}_1\ne f\left(T,x\right)\end{array}\\ \iff \frac{\stackrel{.}{\mathrm{Q}}}{{\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1{\mathrm{A.}}_1}\cdot {x|}_0^{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}={-T|}_{T_1}^{{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2}\\ \iff \stackrel{.}{\mathrm{Q}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1\cdot {\mathrm{A.}}_1\cdot \left(T_1-T_2\right)}{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}\end{array}$$

T1

Temperatur im Brennerraum

T2

Temperatur in der Zwischenebene zwischen Trägerplatte und Verzinkungskesselwand

t1

Dicke der Trägerplatte

A1

Fläche durch die die Wärmeleistung Q strömt

The first system is preferably the carrier plate, wherein

T1

Temperature in the burner chamber

T2

Temperature in the intermediate level between the carrier plate and the galvanizing vessel wall

t1

Thickness of the carrier plate

A1

Area through which the heat output Q flows

wobei gilt:

T3

Temperatur in der Zwischenebene zwischen Trägerplatte und Verzinkungskesselwand

T4

Temperatur an der Innenwand des Verzinkungskessels

t2

Dicke des Verzinkungskessels

A2

Fläche, durch die die Wärmeleistung Q strömt

In the case of a second system, in particular which has a flat plate, preferably the galvanized wall, and preferably adjoins the first system, given a thermal conductivity λ ₂ with a thickness t _{2 of} a plate, that $$\begin{array}{l}\begin{array}{cc}\frac{\stackrel{.}{\mathrm{Q}}}{{\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2{\mathrm{A.}}_2}={\displaystyle \underset{t_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}{\int }}\mathit{dx}=-{\displaystyle \underset{T_3}{\overset{T_{\mathrm{4th}}}{\int }}\mathit{dT}}}& {\lambda }_2\ne f\left(T,x\right)\end{array}\\ \iff \stackrel{.}{\mathrm{Q}}={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2\cdot {\mathrm{A.}}_2\cdot \frac{T_3-{\mathrm{<figure-callout\; id="2"\; label="T\; 4th\; t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathrm{4th}}}{t_{}}\end{array}$$

where:

T3

Temperature in the intermediate level between the carrier plate and the galvanizing vessel wall

T4

Temperature on the inside wall of the galvanizing kettle

t2

Thickness of the galvanizing kettle

A2

Area through which the heat output Q flows

wobei dieser Annahme zugrunde liegt, dass die Messwerterfassung auf den gleichen Flächenbereich wirkt. Ferner kann die Annahme getroffen werden, dass bei Verwendung des gleichen Materials für die Trägerplatte als wie für die Verzinkungskesselwand die Wärmeleitfähigkeiten gleichzusetzen sind. $${\lambda }_1={\lambda }_2$$

From this it can be deduced that $$\begin{array}{l}{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">T</figure-callout>}}_3={\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\\ {\mathrm{A.}}_1={\mathrm{A.}}_2\end{array}$$

this assumption is based on the fact that the measured value acquisition acts on the same surface area. Furthermore, it can be assumed that when the same material is used for the carrier plate as for the galvanizing vessel wall, the thermal conductivities are to be equated. $${\mathrm{<figure-callout\; id="1"\; label="\lambda "\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_1={\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2$$

$$\begin{array}{l}\Rightarrow \frac{\lambda }{t_1}A\left(T_1-T_2\right)=\frac{\lambda }{t_2}A\left(T_2-T_4\right)\\ \iff t_2=t_1\cdot \frac{T_2-T_4}{T_1-T_2}\end{array}$$

The following relationship for determining the wall thickness of the galvanizing kettle can be derived from this (with λ ₁ = λ and A ₁ = A ): $$\begin{array}{l}\begin{array}{cc}\dot{Q}& =\frac{\mathrm{<figure-callout\; id="1"\; label="\lambda \; t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}{t_{}}\mathrm{A.}\left(T_1-T_2\right)\\ \dot{Q}& =\frac{\mathrm{<figure-callout\; id="2"\; label="\lambda \; t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}{t_{}}\mathrm{A.}\left(T_2-T_{\mathrm{4th}}\right)\end{array}\\ \mathrm{With}\dot{Q}=\mathit{const}.\end{array}$$

$$\begin{array}{l}<figure-callout\; id="1"\; label="\Rightarrow \; \lambda \; t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">\Rightarrow </figure-callout>\frac{\lambda }{t_{}}\frac{{}_1}{}\mathrm{A.}\left(T_1-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\right)=\frac{\mathrm{<figure-callout\; id="2"\; label="\lambda \; t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}{t_{}}\mathrm{A.}\left(T_2-T_{\mathrm{4th}}\right)\\ \iff {\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">t</figure-callout>}}_2={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1\cdot \frac{T_2-T_{\mathrm{4th}}}{T_1-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2}\end{array}$$

Only when using different materials does the calculation need to be carried out with the corresponding, in particular known, heat transfer coefficients or thermal conductivities λ ₁ , λ _{2 of} the materials used.

The temperature T ₄ (temperature on the inner wall of the galvanizing kettle) and the temperature T ₁ (temperature in the burner space) are preferably recorded by the further sensor. If the monitoring device is used in an existing hot-dip galvanizing boiler, the device for hot-dip galvanizing already having sensors for measuring the temperature in the burner space and in the zinc melt, the measured values of these existing sensors can advantageously be used. In principle, it is also conceivable, if there are no measured values for the temperature in the burner space or for the temperature in the zinc melt, to estimate these in particular by means of further measured values.

In a further preferred embodiment of the device according to the invention, it is provided that at least one sensor is provided on an additional wall section, in particular extending over the entire height and / or length of the galvanizing vessel. The galvanizing kettle can in principle have a multilayer design, in particular it provides an outer outer kettle surrounding the inner part of the galvanizing kettle. The additional wall or the wall section can preferably assume a supporting function for the galvanizing kettle, so that this is relieved. It is advantageous that, compared to a full boiler that fully encompasses the galvanizing boiler, a material-saving design is made possible while at the same time relieving the galvanizing boiler, so that only areas are covered where the burners are also arranged or the heat input zones are provided. In particular, the side surfaces, in particular the burnerless areas, preferably the bottom and in particular the end faces, cannot be arranged on an additional wall section, which preferably extends over the entire height and width of the associated galvanizing vessel wall. Preferably, due to the hydrostatic pressure of the galvanizing vessel, which is transmitted in particular to the outer wall, the gap between the wall section and the galvanizing vessel wall, in particular due to the manufacturing process, is closed. The detection of the wall thickness takes place in particular analogously to the measurement method already described for the carrier plate, since the sensor records the temperature on the wall of the galvanizing vessel, which is aligned with the wall section.

Incidentally, in a further advantageous embodiment of the inventive concept it is provided that the sensor and / or the sensors are provided in the space, in particular in the boundary surface of the wall, on the outside, at least in some areas, on an outer kettle surrounding the galvanizing kettle. The at least one sensor records the temperature of the interface in the space between the wall of the galvanizing kettle and the outer kettle, which can be roughly equated to the temperature of the outer wall of the galvanizing kettle, so that the wall thickness can be determined using the one-dimensional, flat heat equation (first Fourier's Law). The outer boiler is particularly advantageous with regard to operational safety, since it prevents the zinc melt from running out in the event of a breakdown in the galvanizing boiler or in the event of a leak in the galvanizing boiler.

In addition, the wall thickness of the galvanizing kettle can preferably be reduced due to the outer kettle, in particular from 50 mm to 30 mm, the kettle service life not having to be reduced. In this case, the reduction in the wall thickness of the galvanizing vessel results in a reduced transport and lifting weight, so that the logistical effort when replacing a galvanizing vessel can be significantly reduced. The outer boiler preferably takes on part of the load-bearing function with regard to the absorption of the load as a result of the hydrostatic pressure of the zinc melt from the galvanizing boiler, so that the stress state in the galvanizing boiler material can preferably be considerably reduced. In this way, corrosion due to stress, also called stress corrosion, can be largely reduced. In particular, this results in a reduction in the total removal of the boiler wall thickness.

The galvanizing kettle is preferably let into the outer kettle so that there is a gap between the unfilled galvanizing kettle and the outer kettle. Usually, the gap is required with a view to assembling and to compensate for manufacturing tolerances. As the galvanizing kettle is filled with the zinc melt in the inside of the kettle, the gap closes due to the hydrostatic pressure caused by the zinc melt, so that preferably both kettles come into direct contact with one another. If the sensor or sensors are provided on the inside of the outer kettle facing the galvanizing kettle, this preferably results in a preferably almost exact recording of the temperature on the galvanizing kettle wall, advantageously without the influence of interfering influences or false signals. In addition, full-surface contact of the boiler walls creates an optimal heat transfer due to the heat conduction from the outer boiler to the galvanizing boiler, with the outside of the outer boiler facing the burner device. In this embodiment, the at least one sensor is protected from the high thermal loads on the burner device by the outer boiler wall.

In addition, it is particularly advantageous if the outer vessel and / or the wall section and / or the carrier plate have increased strength compared to the galvanizing vessel. In this context, it is particularly advisable to make the aforementioned components from a steel of the type S355. S355 steels are used in particular for stressed parts in machine and steel construction. Preferably the S355 steel has a increased strength than the material of the galvanizing kettle, in particular wherein the galvanizing kettle is preferably made of VZH steel. VZH steel is preferably used for galvanizing and lead melting pans as well as for similar purposes. VZH steel is a soft special steel that is melted without the addition of silicon. The calming takes place with aluminum, whereby the aluminum content is matched to the nitrogen content. In particular, the standard version of a VZH galvanizing kettle has a strength at a temperature of 450 ° C of less than 55 MPa. The minimum yield strength, especially for sheet metal thicknesses between 35 and 70 mm, is around 175 MPa for VZH steel at room temperature. In contrast to this, the minimum yield strength at room temperature for an S355 steel is 355 MPa, in particular where the strength at a temperature of approximately 450 ° C. is 250 MPa. Accordingly, the strength in the existing temperature range of the hot-dip galvanizing of an S355 steel is preferably five times higher than that of a VZH steel, so that in particular the required cross-section of the boiler plate to absorb the same load can be considerably lower.

The sensor is advantageously arranged in areas on the outside of the wall of the galvanizing vessel and / or rests against the outside of the wall of the galvanizing vessel. In the case of direct contact with the outer wall of the galvanizing kettle, the wall layer thickness of the galvanizing kettle can be determined directly via the temperature of the outside of the galvanizing kettle, in particular without the use of a further wall. For this purpose, the one-dimensional, stationary heat equation of a flat wall is used. In the one-dimensional stationary heat equation, the temperature is only a function of the x-coordinate and the heat is only transferred in this direction. For example, as in the case of the galvanizing kettle, a wall of thickness t _{2 separates} a hot fluid, in particular a molten zinc melt, from an outer region. The wall temperatures on the hot and cold sides are _{denoted by T 3} and T ₄ , respectively.

With a suitable form of the heat equation with regard to the one-dimensional stationary heat conduction without energy generation in the wall, the following equation can be applied: $$\dot{Q}=-\lambda \cdot \mathrm{A.}\frac{\mathit{dT}}{\mathit{dx}}$$

With a known thermal output, conclusions can be drawn about the wall thickness.

If the wall thickness is to be calculated without using the heat output, a further wall is to be provided in particular to determine the wall thickness by means of the temperature, for example in the form of a carrier plate and / or a wall section and / or an outer vessel. In this context, it goes without saying that the temperature can also be measured by means of at least one sensor directly on the outside of the wall of the galvanizing vessel using a carrier plate and / or a further wall section and / or an outer vessel.

In addition, it is particularly advantageous if the monitoring device has at least one storage device for storing the measured and / or calculated and / or derived values. The storage device can in particular be designed in such a way that the operating states are recorded so that evidence of certain processes in the galvanizing operation can be ensured. As a result, this storage is also particularly advantageous if a fault has occurred that is to be evaluated later. In addition, the time course of the boiler wall thickness can be viewed and / or taken into account by means of a memory device, so that not only can an immediate reaction to characteristic values take place, but also a creeping course or change in the characteristic values can be reacted to. A storage device consequently offers the possibility of sustainably optimizing the galvanizing process and making it more efficient.

The monitoring device preferably has a display device for optical and / or acoustic display, in particular the display device being coupled to the evaluation device in such a way that a display signal is displayed when the wall thickness of the wall of the galvanizing vessel falls below a predetermined limit value. In this context, it is also understood that the display device can be coupled to the memory device, so that a display of a time profile of the characteristic values is also made possible. In particular, it is possible for the galvanizing personnel to understand the change in the wall thickness of the galvanizing kettle over time, so that the galvanizing kettle can be used more efficiently.

A wall thickness in the range from 5 to 30 mm, preferably between 10 to 25 mm, more preferably between 15 to 20 mm, in particular at least substantially 20 mm, is to be regarded as the limit value of the wall thickness of the wall of the galvanizing vessel. A wall thickness of 20 mm has already reached a critical condition of the galvanizing kettle and a possible global and / or local loss of stability of the galvanizing kettle cannot be ruled out, so that when the critical wall thickness or the limit value of the wall thickness is reached, it is particularly advantageous to send a notification.

The monitoring device is advantageously coupled to a burner device having at least one burner, the monitoring device being designed to control the burner device. The burner device brings the required thermal energy into the zinc melt via the galvanizing vessel wall. Ultimately, it goes without saying that the burner device preferably has a plurality of burners, which are preferably distributed around the circumference and / or the height of the galvanizing kettle, and secondly, in particular equally spaced apart, are aligned on its outer wall, with the burners creating a heat input zone on the Galvanizing boiler wall is formed. The area of the outer wall of the galvanizing kettle that is directly covered by the flame of the burner or the flame cone of the burner is referred to as the heat input zone. Due to the invention, it is now possible to design the heat input zone in such a way that individual, in particular local, elevated temperature ranges, so-called “hotspots”, are avoided. For this purpose, the individual burners of the burner devices can be controlled via the control device in terms of their burner output and / or their orientation. In particular, the burner device is to be controlled and / or aligned in such a way that an at least substantially uniform heat input zone results on the outer wall of the galvanizing kettle.

The control device of the burner device is preferably designed in such a way that the boiler wall thickness is removed evenly. In particular, minimal removal of the boiler wall should be ensured. If the characteristic values deviate from predetermined setpoint values, the combustion output of a burner can be changed, for example. In addition, it is also conceivable to change the focal cone of a burner, in particular in which the direction of the burner is changed. For example, the heat input zones can be set. In the case of a plurality of burners, an individual setting is preferably provided for each burner. When a maximum and / or minimum limit value of a characteristic value is reached, for example 20 mm as the wall thickness of the wall, an immediate shutdown of the burner device can also be initiated. As a result, the burner device can be set as a function of the recorded measured values and, in particular, as a function of the time course of characteristic values, so that there is an increase in material efficiency and a longer service life of the galvanizing kettle.

The control of the burner device is advantageously implemented via the gas supply and / or the air supply to the burner of the burner device. In this way, the gas supply and / or the air supply can be adapted to the effect that there is an increased or a reduced thermal output of the burner.

Incidentally, in a further embodiment variant of the inventive concept, it is provided that the burner device has at least two independently controllable burners. Two independent burners offer the advantage that different heat input zones are possible on the galvanizing kettle or the wall of the galvanizing kettle if this is necessary due to the galvanizing process and the components introduced into the galvanizing bath.

The heat introduction zones are advantageously arranged at a distance from one another on the outside of the galvanizing kettle, so that uniform heating or a constant temperature of the zinc melt is ensured.

In addition, in a further particularly preferred embodiment of the device according to the invention, it is provided that the sensor and / or the sensors are arranged in the region of a heat input zone of the burner device. This arrangement of the sensor and / or the sensors is advantageous because possible "hotspots" can arise primarily in areas of the heat input zone. By arranging at least one sensor in at least one heat input zone, it can be ensured that these zones, which in particular are subject to an increased risk of increased boiler wall removal, can be continuously monitored so that a breakthrough in the boiler wall in the area of a heat input zone can be avoided or bypassed .

In a preferred embodiment it is provided that the burner of the burner device is provided in the area of a furnace support structure surrounding the galvanizing kettle at a distance. The burners or the burner of the burner device are directed towards the outside of the galvanizing kettle. In the case of a plurality of burners, these are distributed over the circumference of the outside of the galvanizing vessel, it being advisable for the burners to be spaced from one another at the same distance. In addition or in addition, it can be provided that adjacent burners are arranged offset from one another in relation to the boiler height and thus fire areas of the galvanizing boiler of different heights with respect to the boiler height. Such an arrangement is particularly suitable for flat flame burners.

When using high-speed burners, which are positioned in particular at the front and fire into the burner space parallel to the longitudinal wall of the galvanizing kettle, a planar arrangement of the sensors is advantageously provided.

In the case of flat flame burners, the flame rests against the furnace wall around the burner outlet, in particular due to the geometry and the flow velocity, so that the flame extends in a ring around the burner outlet. Starting from the burner outlet, the heat or energy is introduced evenly into the burner chamber. Flat flame burners are characterized by both high flame stability and the possibility of changing cold or heated burner air.

High-speed burners are characterized by a high flame exit speed of the hot gas and consequently ensure an effective mixing of the furnace atmosphere or the burner chamber atmosphere. Furthermore, these burners are characterized by a stable burning behavior, even in the under- and / or over-stoichiometric range.

In the case of flat flame burners in particular, there is generally increased removal in the area of the heat input area or the heat input zone of the burner. In the case of high-speed burners, on the other hand, there may be increased removal of the wall of the galvanizing kettle in the area along the flame. In a particularly preferred embodiment, the carrier plate is therefore only installed in the areas on which the burner acts. The sensor or the sensors are preferably in the areas of increased removal Wall of the galvanizing vessel arranged so that a local and / or global loss of stability can be avoided.

Another object of the present invention - according to a second aspect of the present invention - is a method for hot-dip galvanizing of components, in particular using a device according to the invention, as described above, for hot-dip galvanizing in a zinc melt, the zinc melt in a zinc bath formed by a wall of a galvanizing kettle The inside of the boiler is located and / or arranged, the wall thickness of the wall of a galvanizing boiler being monitored during galvanizing operation by means of a monitoring device, at least one sensor provided in the area of the outside of the wall of the galvanizing boiler measuring at least the temperature of the galvanizing boiler and an evaluation device coupled to the sensor processes the recorded measured value and calculates and / or derives the wall thickness of the wall of the galvanizing vessel.

The monitoring of the hot-dip galvanizing device offers - as already explained above - the advantage that increased boiler wall removal can be recognized early and / or corrective measures can be taken and / or that the boiler wall removal is minimized and continuously recorded. As a result, in particular the boiler service life can be increased and / or the minimum boiler wall thickness can be reduced. By monitoring the wall thickness of the galvanizing kettle, it is possible to avoid a breakthrough in the galvanizing kettle, which is caused in particular by thermal "hotspots". As a result, both the operational safety is increased and, moreover, the production and repair costs of the galvanizing kettle are reduced. For further advantages that result in connection with the method according to the invention, express reference is made to the above statements in connection with the hot-dip galvanizing device according to the invention.

As described above, it is provided in the method according to the invention that at least one sensor provided in the area of the outside of the wall of the galvanizing kettle measures at least the temperature of the galvanizing kettle and an evaluation device coupled to the sensor measures the recorded measured value, preferably with further recorded characteristic values, processed and the wall thickness of the wall of the galvanizing vessel is calculated and / or derived therefrom. By measuring or determining the wall thickness by means of the sensor, in particular indirect, the monitoring of the wall of the galvanizing kettle can take place. It goes without saying that a plurality of sensors generate a redundancy of the monitoring device and to this end it is advantageous if a plurality of sensors is used, in particular in the area of a heat input zone. The wall thickness can be determined by the recorded measured value or the determined characteristic value, so that an evaluation device can determine the desired wall thickness.

Another sensor preferably measures further measured values of the device for hot-dip galvanizing, in particular the temperature of the zinc melt and / or the temperature in the burner space. The further sensor advantageously transfers the measured value to the evaluation device for determining the wall thickness of the wall of the galvanizing vessel.

A continuous measurement value acquisition is preferably carried out by means of at least one sensor. The continuous acquisition of measured values is to be implemented in such a way that a measured value acquisition of at least one characteristic value, in particular to determine the wall thickness of the wall, is carried out at regular intervals. The continuous recording of measured values offers the advantage that the wall thickness of the galvanizing kettle can be monitored during the entire galvanizing operation, so that it is possible to react individually to extraordinary operating situations or malfunctions.

In a further preferred embodiment of the method it is provided that at least one storage device of the monitoring device stores the, in particular calculated and / or derived values. Storing the values, in particular the wall thickness, enables the change in the value over time to be traced in order to derive or recognize any deviations from the target value or target curve. The monitoring device can also be designed in such a way that not only limit values for the wall thickness of the galvanizing vessel are monitored, but also increased vessel wall removal over a certain period of time. This can possibly detect errors in the galvanizing period. In any case, it is possible that the boiler wall removal is reproduced by the storage device and a functional relationship between the boiler wall thickness of the galvanizing boiler, the galvanizing process and / or the time is established.

It is particularly preferred that a display device of the monitoring device displays an optical and / or acoustic display signal. This display signal is preferably displayed when the wall thickness of the wall of the galvanizing kettle falls below a predetermined limit value. Advantageously, the display device is coupled to the evaluation device so that it can be recognized that the value falls below a predetermined limit. The limit value of the wall thickness of the wall of the galvanizing vessel is preferably about 20 to 25 mm and / or is in a range from 5 to 30 mm, preferably 10 to 25 mm. An optical and / or acoustic signal enables, in addition to a possible, preferably automated, control of the burner device, manual intervention by the operators of the galvanizing kettle, so that the operators are made aware of a fault situation. The operating personnel can, for example, initiate an immediate shutdown of the burner device and / or are made aware that particular areas of the galvanizing kettle must be given special attention. The monitoring device is preferably coupled to a burner device having at least one burner, the monitoring device controlling the burner device. Controlling the burner device via the monitoring device ensures that the burner device can influence the heat input zones on the wall as a function of the wall thickness of the wall of the galvanizing vessel. It is thus possible to enlarge or reduce a heat input zone with the same, increased or reduced heat output. In addition, especially in the case of an automated process, thermal hotspots on the wall of the galvanizing kettle or on the outside facing the burners can be avoided. Controlling the burner device by means of the monitoring device enables the burner device to be coupled to the evaluation device and / or the storage device. The coupling of the burner device to the evaluation device acquiring the measurement data ensures that, in particular, an optimized introduction of heat into the zinc melt can take place and that the wall thickness of the galvanizing kettle is preferably evenly removed.

In addition, it is particularly advantageous if the monitoring device controls the gas supply and / or the air supply to the burner of the burner device so that the burner output can be based on the calculated and / or derived wall thickness of the wall of the galvanizing vessel. Ultimately, the monitoring device can not only control the gas supply and / or the air supply to the burner, but in particular also the alignment of the burner, preferably the burner cone, or, in particular with a plurality of burners, can control individual burners and / or operate or operate the burners separately even switch off.

As a result, the invention relates to a device for hot-dip galvanizing of components with a galvanizing kettle for receiving a zinc melt in the boiler interior, a monitoring device being provided for monitoring the wall thickness of the wall of the galvanizing kettle during operation of the galvanizing kettle. In addition, the invention provides a method using the aforementioned device for hot-dip galvanizing of components. The wall thickness of the wall of the galvanizing vessel can in particular be calculated and / or derived from at least one measurement or characteristic value that is measured or derived by the monitoring device.

Further features, advantages and possible applications of the present invention emerge from the following description of exemplary embodiments with reference to the drawing and the drawing itself. All of the features described and / or illustrated form the subject matter of the present invention individually or in any combination, regardless of their Summary in the claims or their back-references.

Fig. 1

eine schematische Querschnittsansicht eines erfindungsgemäßen Verzinkungskessels,

Fig. 2A

eine schematische Querschnittsansicht einer Alternative des Details A aus Fig. 1,

Fig. 2B

eine schematische Querschnittsansicht einer anderen Ausführungsform des Details A aus Fig. 1,

Fig. 3

eine schematische Querschnittsansicht einer weiteren Ausführungsform eines erfindungsgemäßen Verzinkungskessels,

Fig. 4

eine schematische perspektivische Ansicht einer weiteren Ausführungsform eines erfindungsgemäßen Verzinkungskessels,

Fig. 5

eine schematische Draufsicht auf eine erfindungsgemäße Trägerplatte,

Fig. 6

eine schematische Darstellung der Temperaturabnahme über die Wandstärke eines Verzinkungskessels,

Fig. 7

eine schematische Darstellung der Temperaturabnahme über die Wandstärke einer weiteren Ausführungsform eines Verzinkungskessels,

Fig. 8

eine schematische Darstellung der Temperaturabnahme über die Wandstärke einer weiteren Ausführungsform eines Verzinkungskessels,

Fig. 9

eine schematische Darstellung der erfindungsgemäßen Überwachungseinrichtung und

Fig. 10

eine schematische Ansicht von Teilen eines Verzinkungskessels unter Verwendung von Hochgeschwindigkeitsbrennern.

It shows:

Fig. 1

a schematic cross-sectional view of a galvanizing kettle according to the invention,

Figure 2A

a schematic cross-sectional view of an alternative of the detail A from FIG Fig. 1 ,

Figure 2B

a schematic cross-sectional view of another embodiment of the detail A from Fig. 1 ,

Fig. 3

a schematic cross-sectional view of a further embodiment of a galvanizing kettle according to the invention,

Fig. 4

a schematic perspective view of a further embodiment of a galvanizing kettle according to the invention,

Fig. 5

a schematic plan view of a carrier plate according to the invention,

Fig. 6

a schematic representation of the temperature decrease over the wall thickness of a galvanizing kettle,

Fig. 7

a schematic representation of the temperature decrease over the wall thickness of a further embodiment of a galvanizing kettle,

Fig. 8

a schematic representation of the temperature decrease over the wall thickness of a further embodiment of a galvanizing kettle,

Fig. 9

a schematic representation of the monitoring device according to the invention and

Fig. 10

Figure 3 is a schematic view of parts of a galvanizing kettle using high speed burners.

Fig. 1 shows a device 1 for hot-dip galvanizing of components 2, with a galvanizing kettle 3 for receiving a zinc melt 4 in a boiler interior 5 formed by a wall 8 of the galvanizing kettle 3. In the case of the device 1 for hot-dip galvanizing shown, it is provided that a monitoring device 6 - according to Fig. 9 - Is provided for monitoring the wall thickness 7 of the wall 8 of the galvanizing vessel 3 during the galvanizing operation. The components 2 to be galvanized are immersed in the zinc melt 4 of the galvanizing kettle 3 by means of a goods carrier 21 which is movably attached to a traverse 23 via a trolley 22, for example. The galvanizing operation occurs when the components 2 are immersed in the zinc melt 4 and / or when the zinc melt 4 is kept in a molten state.

How out Fig. 1 results, the galvanizing kettle 3 is enclosed in a support structure of the furnace 25. The Figure 2A shows that the monitoring device 6 - according to Fig. 9 - At least one, in particular provided in the area of the outside 9 of the wall 8 of the galvanizing vessel 3, sensor 10 for measurement has at least one characteristic value, namely the temperature of the galvanizing kettle 3. In the illustrated embodiment according to Figure 2A is a plurality of sensors 10 on the inside of the outer vessel 15 or according to the alternative Figure 2B provided on the outside 9 of the galvanizing kettle 3. The Figures 2A and 2B are schematic insofar as the space 14 between the outer vessel 15 and the wall 8 of the galvanizing vessel 3 is shown wider than as shown in FIG Fig. 1 is provided. In fact, the interspace 14 is so narrow that the interspace 14 as such does not actually represent a “interspace”. The interspace 14 was shown schematically to illustrate the area of the boundary surface of the wall 8 of the galvanizing vessel 3. A schematic widening of the interspace 14 was additionally shown to illustrate the arrangement of the sensor or sensors 10 according to FIG Figures 2A and 2B elected. The outer boiler 15 comprises the galvanizing boiler 3, which means that the outer boiler 15 is ultimately part of the galvanizing boiler 3. Ultimately, it goes without saying that a multi-layer structure of the galvanizing vessel 3 can be provided in a further exemplary embodiment. In this case, no separate external boiler 15 is provided. In this embodiment, the sensors or the sensor 10 are arranged on the outside 9 of the wall 8 of the galvanizing vessel 3.

The Fig. 9 shows that the sensor 10 is coupled to an evaluation device 11, the evaluation device 11 being provided as a characteristic value for processing the measured value recorded by the sensor 10 and for calculating and / or deriving the wall thickness 7 of the wall 8 of the galvanizing kettle 3. The sensor 10 transmits the measured value to the evaluation device 11 by means of a signal, in particular an electrical signal.

It is not shown that the monitoring device 6 is designed in such a way that a continuous measurement value acquisition takes place. In the present embodiment, measured values are recorded at regular time intervals that are between one minute and one hour. For example, it is possible to record measured values every ten minutes. The respective measured values are processed via the evaluation device 11 independently of the frequency of the measurement value acquisition.

Furthermore, it is not shown that further sensors 10 and / or a further sensor are provided for measuring further characteristic values and / or measured values of the device 1 for hot-dip galvanizing. The other measured values relate, for example, to the burner chamber and / or the boiler interior 5 and / or to the molten zinc 4. In particular, the temperature in the burner chamber and / or the temperature of the molten zinc 4 is measured, preferably to determine the wall thickness 7 of the wall 8 of the galvanizing boiler 3, together with the temperature in the intermediate plane 14 and / or in the area of the boundary surface of the wall 8 of the galvanizing vessel 3. In addition, it is not shown that the further sensor 10 is coupled to the evaluation device 11.

The wall thickness 7 of the wall 8 of the galvanizing kettle 3 can be determined by measuring the temperature in the interface of the wall 8 of the galvanizing kettle 3, in particular with the aid of the standard and / or additionally recorded temperatures in the burner space and in the zinc melt 4. The sensor 10, in particular designed as a temperature sensor, is provided in the area of the boundary surface of the wall 8 of the galvanizing kettle 3. This is also used in Figures 2A and 2B made clear.

Using a calculation example, it is illustrated below how the wall thickness 7 of the galvanizing kettle 3 can be calculated from the temperature.

mit λ ₁ = λ ₂

T1

Temperatur im Brennerraum, Außenseite der Trägerpatte 12 und/oder des Außenkessels 15 und/oder des Wandabschnitts 13

T2

Temperatur in der Zwischenebene zwischen Trägerplatte 12 und Verzinkungskessel 3 (Innenseite Trägerplatte 12/Außenseite 9 des Verzinkungskessels 3)

T4

Temperatur an der Innenwand des Verzinkungskessels 3

t1

Wanddicke der Trägerplatte 12 und/oder des Außenkessels 15 und/oder des Wandabschnitts 13

t2

Wandstärke 7 der Wandung 8 des Verzinkungskessels 3

First, the sensor 10 is calibrated in the border area of the wall 8 of the galvanizing kettle 3, preferably when the galvanizing kettle 3 is new and / or when the monitoring device 6 is installed, in particular at least with knowledge of a known wall thickness 7. The formula (10) is used: $${\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">t</figure-callout>}}_2\cdot \left(T_1-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2\right)={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1\cdot \left(T_2-T_{\mathrm{4th}}\right)$$

with λ ₁ = λ ₂

T1

Temperature in the burner space, outside of the support plate 12 and / or of the outer boiler 15 and / or of the wall section 13

T2

Temperature in the intermediate level between carrier plate 12 and galvanizing kettle 3 (inside carrier plate 12 / outside 9 of galvanizing kettle 3)

T4

Temperature on the inside wall of the galvanizing kettle 3

t1

Wall thickness of the carrier plate 12 and / or of the outer vessel 15 and / or of the wall section 13

t2

Wall thickness 7 of the wall 8 of the galvanizing kettle 3

$$T_2=\frac{t_2{T}_1+t_1\cdot T_4}{t_1+t_2}$$

• t ₁ = 20 mm
• t ₂ = 50 mm
• T ₁ = 600° C
• T ₄ = 450° C

$$\begin{array}{cc}{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{50\cdot 600+20\cdot 450}{50+20}& \frac{\mathrm{mm}\cdot °\mathrm{C}}{\mathrm{mm}}\end{array}$$

T ₂ = 557,14 °CThe following transformation can be used to determine the temperature T _2: $$T_2\left(-t_2-{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1\right)=-t_2{T}_1-{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1\cdot T_{\mathrm{<figure-callout\; id="2"\; label="4th\; T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">4th\; </figure-callout>}}$$

$$T_{}$$$${}_2=\frac{t_2{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">T</figure-callout>}}_1+{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1\cdot {\mathrm{<figure-callout\; id="1"\; label="T\; 4th\; t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathrm{4th}}}{t_{}}$$

• t ₁ = 20 mm
• t ₂ = 50 mm
• T ₁ = 600 ° C
• T ₄ = 450 ° C

$$\begin{array}{cc}{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2=\frac{50\cdot 600+\mathrm{20th}\cdot 450}{50+\mathrm{20th}}& \frac{\mathrm{mm}\cdot °\mathrm{C.}}{\mathrm{mm}}\end{array}$$

T ₂ = 557.14 ° C

The calculation assumes that the temperature distribution in the burner space as well as in the boiler interior 5 or in the galvanizing boiler 3 is to be regarded as homogeneous. _{The theoretical temperature T 2} set in the interface or in the intermediate space 14 is detected by means of the sensor 10. The calibration can be carried out in the new condition by comparing the theoretical target value and the actual recorded actual value.

In the case of continuous recording of measured values, for example, a state results after eight years, which is characterized by the fact that Wall thickness of the carrier plate 12 and / or of the outer vessel 15 and / or of the wall section 13 t ₁ = 20 mm Temperature in the burner chamber T ₁ = 600 ° C Temperature inside the galvanizing kettle 3 T ₄ = 450 ° C Temperature in the boundary plane or the boundary surface of the wall 8 of the galvanizing kettle 3 T ₂ = 535 ° C

The thickness or the wall thickness 7 of the galvanizing vessel 3 can be determined as follows: $${\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">t</figure-callout>}}_2={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1\cdot \frac{T_2-T_{\mathrm{4th}}}{T_1-{\mathrm{<figure-callout\; id="2"\; label="T"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">T</figure-callout>}}_2}$$

t ₂ = 26,15 mmWith the known sizes it results: $${\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="imgf0001.png,imgf0007.png"\; state="\{\{state\}\}">t</figure-callout>}}_2=\mathrm{20th}\cdot \frac{535-450}{600-535}\mathrm{mm}$$

t ₂ = 26.15 mm

There is thus a significant decrease in the wall thickness 7 of the galvanizing vessel 3 after eight years from 50 mm to 26 mm. This critical wall thickness 7 of the galvanizing kettle 3 can be continuously monitored by the monitoring device 6 and if the value falls below a limit value, for example below 25 mm, either a display signal and / or countermeasures can be triggered or initiated.

Otherwise, it is not shown that the sensor 10 is designed as a thin-film thermocouple and / or as a jacket thermocouple. In particular, the sensor 10 withstands thermal loads of over 650 ° C.

As already explained, the Fig. 2 that a plurality of sensors 10 distributed over an area of the outside 9 of the wall 8 of the galvanizing vessel 3 is provided. This plurality of sensors 10 is either on the inside of the outer vessel 15 (according to FIG Figure 2A ) and / or on the outside of the galvanizing kettle 3 (according to Figure 2B ) intended. The sensors 10 in particular detect the temperature in the space 14 between the outer boiler 15 and the galvanizing boiler 3, in particular the interface of the wall 8 of the galvanizing boiler 3.

The sensors 10 can be attached or arranged on the outside 9 of the galvanizing vessel 3 in various ways. Fig. 3 shows schematically that the sensor 10, in Fig. 3 the sensors 10 is / are provided on a carrier plate 12. The carrier plate 12 is preferably in the area of a heat input zone 20 - according to FIG Fig. 1 - Arranged, wherein the heat introduction zone 20 is exposed to an increased thermal load. The The sensor or sensors 10 can be placed on the carrier plate 12 in the form of a network (according to FIG Fig. 5 ) or individually.

The Fig. 4 shows that the sensor or sensors 10 are provided on a wall section 13. According to Fig. 4 The wall section 13 extends over the entire height and over the entire height of the galvanizing vessel 3 and over the entire height of the galvanizing vessel 3 Fig. 4 is schematic insofar as it does not show the support structure of the furnace 25 or the burner device 18 and also shows the gap between the outside 9 of the wall 8 of the galvanizing kettle 3 and the inside of the wall section 13 enlarged, as well as the wall section to clarify the arrangement of the sensors 10 13 does not assign a thickness. In further, not shown embodiments, it can be provided that the wall section 13 extends over the entire height and / or length of the galvanizing vessel 3. The sensors 10, which are incorporated on the carrier plate 12 and / or the wall section 13, are flush with the outside 9 of the wall 8 of the galvanizing vessel 3. In addition to the arrangement of the sensors 10 on a wall section 13 and / or on a carrier plate 12, it is according to FIG Fig. 1 and 2 It is also conceivable to provide the sensor 10 or the sensors 10 on an external boiler 15 surrounding the galvanizing boiler 3. The sensors 10 are in the intermediate space 14 or the boundary surface of the wall 8 - in the exploded view of FIG Figure 2A 1 and B - arranged, preferably on the inside of the outer kettle 15, which is separate from the galvanizing kettle 3.

In addition, the Fig. 9 the monitoring device 6. In addition to the at least one sensor 10 and the evaluation device 11, the monitoring device 6 has a storage device 16. The storage device 16 is used to store the measured and / or calculated and / or derived values, in particular the wall thickness 7 of the wall 8 of the galvanizing kettle 3. The signal containing the values is fed to the memory device 16 via the evaluation device 11. The evaluation device 11 also receives the measured value of the sensor 10 via a signal. Furthermore, the monitoring device 6 has a display device 17 for optical and / or acoustic display. According to Fig. 9 the display device 17 is coupled to the evaluation device 11. This coupling leads to the fact that, for example, if the wall thickness 7 of the wall 8 of the galvanizing vessel 3 falls below a predetermined limit value, a display signal, in particular optical and / or acoustic, is shown. The display device 17 can receive a signal for triggering a display signal both from the evaluation device 11 and from the memory device 16.

Also shows Fig. 9 that a control device 24 is provided in the monitoring device 6, which is used to control a burner device 18. According to Fig. 1 the burner device 18 has at least one burner 19. At the in Fig. 1 A plurality of burners 19 is provided in the embodiment shown. The control device 24 can receive the signals required for control from the display device 17 and / or from the storage device 16 - according to FIG Fig. 9 - receive.

It is not shown that the control device 24 is designed to control the gas supply and / or the air supply of the burner 19 of the burner device 18. The control device 24 can, in particular, control the gas supply and / or air supply to the burner 19 of the burner device 18 in such a way that there is optimum heat transfer through the burner device 18 into the zinc melt 4.

Furthermore, it is not shown that the sensor 10 is arranged in the region of a heat input zone 20. According to Fig. 1 a heat input zone 20 is provided on the galvanizing kettle 3 in the area in which a burner 19 acts on the galvanizing kettle 3. In this area - the heat introduction zone 20 - the thermal energy is introduced into the zinc melt 4 or into the boiler interior 5. In these areas there is an increased thermal load on the galvanizing kettle 3 or on its wall 8.

Fig. 5 shows schematically a carrier plate 12 which is arranged on the outside 9 of the galvanizing vessel 3. The arrangement of the sensors 10 according to Fig. 5 is, in particular in the case of a galvanizing kettle 3 using a flat flame burner, designed in the form of a network structure, preferably in areas of the heat input zone 20. Ultimately, it goes without saying that in a further embodiment, not shown, this arrangement of the sensors 10, in particular in the form of a network in areas of the Heat introduction zone 20, can also be provided on the outer boiler 15 and / or on a wall section 13.

Furthermore, according to Fig. 10 the use of high-speed burners as burners 19 of the burner device 18 can be provided.

It is not shown that the high-speed burners are positioned at the front and fire parallel to the longitudinal wall of the galvanizing boiler 3 into the burner space. Similar to the arrangement of the sensors 10 in flat flame burners according to FIG Fig. 5 a network-like arrangement of the sensors 10 is possible. A planar arrangement of the sensors 10 on the inside of the outer vessel 15 is recommended, as can be seen from this Fig. 10 results. In further, not shown embodiments, it can be provided that the planar arrangement of the sensors 10 is provided on a carrier plate 12 and / or on a wall section 13, as is also the case Fig. 10 results.

When calculating the wall thickness 7 of the wall 8 of the galvanizing boiler 3, the thermal conductivity λ ₁ , also called the coefficient of thermal conductivity or heat transfer coefficient, of both the outer boiler 15 and / or the wall section 13 and / or the carrier plate 12 and the thermal conductivity λ _{2 of} the wall 8 of the Galvanizing kettle 3 required. In the above calculation example, it is assumed that the heat transfer coefficient λ _{1 of} the outer boiler 15 and the heat coefficient λ _{2 of} the galvanizing boiler 3 can be regarded as the same. This simplifies the calculation of the wall thickness 7 of the galvanizing vessel 3.

The Fig. 6 shows schematically the temperature decrease over the wall thickness x with the same thermal conductivities. How out Fig. 6 results, there is a linear relationship between the temperature T and the wall thickness x. With knowledge of the wall thickness 7 of the outer boiler 15 (t ₁ ), the temperature T ₁ in the burner space, the temperature T ₂ on the outside 9 of the galvanizing boiler 3, the temperature T ₄ at the point (t ₁ + t ₂ ), the wall thickness 7 (t ₂ ) of the wall 8 of the galvanizing kettle 3 can be determined. The functional relationship between the temperature T and the wall thickness x is according to Fig. 6 : $$T\left(x\right)={\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">T</figure-callout>}}_1+x\frac{T_2-T_1}{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}$$

If the thermal conductivity λ _{1 of} the outer boiler 15 is greater than the thermal conductivity λ _{2 of} the galvanizing boiler 3, then there is a schematic relationship according to FIG Fig. 7 , the temperature T falling more sharply in the area of the wall thickness 7 of the wall 8 of the galvanizing vessel 3 than in the area of the outer vessel 15. The Fig. 8 shows, however, that there is a schematic relationship between the temperature T and the wall thickness x, with the temperature in the area of the outer vessel 15 falling more sharply than the wall thickness 7 of the galvanizing vessel 3, assuming that the thermal conductivity λ _{1 of} the outer vessel 15 is lower than the thermal conductivity λ _{2 of} the wall 8 of the galvanizing kettle 3.

In addition, a method for hot-dip galvanizing of components 2 in a zinc melt 4, wherein the zinc melt 4 is located and / or arranged in a boiler interior 5 formed by a wall 8 of a galvanizing boiler 3, with a device 1 for hot-dip galvanizing according to FIG Fig. 1 intended. It is not shown that the method for hot-dip galvanizing of components 2 is carried out by means of a device 1 for hot-dip galvanizing with one of the aforementioned embodiments. In the method it is provided that the wall thickness 7 of the wall 8 of the galvanizing vessel 3 is monitored by means of a monitoring device 6 during the galvanizing operation. The Fig. 9 shows the monitoring device 6, which is used to monitor the wall thickness 7 of the galvanizing kettle 3. The Fig. 1 shows the galvanizing kettle 3 in the galvanizing operation, the zinc melt 4 being kept in a hot liquid state and components 2 being immersed in the zinc melt 4 via a goods carrier 21.

According to Figures 2A and 2B At least one sensor 10 is provided in the area of the outside 9 of the wall 8 of the galvanizing vessel 3. A plurality of sensors 10 are provided here. In the exemplary embodiment shown, the sensor 10 measures the temperature on the wall 8 of the galvanizing kettle 3 Fig. 9 The sensor 10 transmits the measured characteristic value, in particular by means of a signal, the temperature in the illustrated embodiment, to the evaluation device 11 coupled to the sensor 10. The evaluation device 11 processes the measured value of the sensor 10 and determines and / or calculates and / or derives the wall thickness 7 of the wall 8 of the galvanizing vessel 3.

What is not shown is that, in a further exemplary embodiment, the characteristic value is continuously recorded to determine the wall thickness 7 of the wall 8 of the galvanizing vessel 3.

It also clarifies the Fig. 9 that a storage device 16 stores the calculated and / or derived values of the evaluation device 11. The storage device 16 can be coupled to a display device 17 of the monitoring device 6. A display device 17 of the monitoring device 6 displays an optical and / or acoustic display signal. What is not shown is that the optical and / or acoustic display signal is displayed when, for example, the wall thickness 7 of the wall 8 of the galvanizing kettle 3 falls below a predetermined limit value, in particular a limit value in the range of 15 to 25 mm. For this purpose, the display device 17 is coupled to the evaluation device 11. Furthermore, it is not shown that a display signal is also triggered by the memory device 16, in particular in the event of a time-critical change in the wall thickness 7 of the wall 8 of the galvanizing kettle 3.
Furthermore, the Fig. 9 that the monitoring device 6 is coupled to a burner device 18, the burner device 18 according to Fig. 1 has at least one burner 19. The monitoring device 6 can according to Fig. 9 control the burner device 18 via a control device 24. The control device 24 receives signals either from the display device 17 and / or from the evaluation device 11 and / or from the storage device 16.

It is not shown that the control device 24 and / or the monitoring device 6 controls the gas supply and / or the air supply of the burner 19 of the burner device 18.

List of reference symbols:

1

Hot-dip galvanizing device

2

Components

3

Galvanizing kettle

4th

Molten zinc

5

Boiler interior

6th

Monitoring device

7th

Wall thickness

8th

Wall

9

Outside of the wall

10

sensor

11

Evaluation device

12th

Carrier plate

13th

Wall section

14th

Space

15th

External boiler

16

Storage facility

17th

Display device

18th

Burner device

19th

burner

20th

Heat input zone

21

Product carrier

22nd

Trolley

23

traverse

24

Control device

25th

Support structure of the furnace

T

temperature

x

Wall thickness

Q̇

Heat output

T1

Temperature in the burner chamber

T2

Temperature in the intermediate level between the outside of the galvanizing kettle and the support plate and / or the outer kettle and / or the wall section

T3

Temperature on the outside of the galvanizing kettle

T4

Temperature on the inside of the galvanizing kettle

A.

Area through which the heat output flows

t1

Thickness of the carrier plate and / or the outer boiler and / or the wall section

t2

Thickness of the galvanizing kettle

λ1

Thermal conductivity of the carrier plate

λ2

Thermal conductivity of the wall of the galvanizing kettle

Claims (19)

1. A device (1) for hot-dip galvanizing components (2), comprising a galvanizing tank (3) for holding the zinc melt (4) in a tank interior (5) formed by a wall (8) of the galvanizing tank (3),
   wherein a monitoring apparatus (6) is provided for monitoring the wall thickness (7) of the wall (8) of the galvanizing tank (3) during the galvanizing operation,
   wherein the monitoring apparatus (6) has at least one sensor (10) provided in the area of the outer side (9) of the wall (8) of the galvanizing tank (3) for measuring at least the temperature of the galvanizing tank (3) and an evaluation device (11) coupled to the sensor (10) for processing the measured value recorded by the sensor (10) and for calculating and/or deriving the wall thickness (7).
2. The device according to claim 1, characterised in
   that the monitoring apparatus (6) is designed in such a way that the measured values are continuously recorded.
3. The device according to claim 1 or 2, characterised in
   that at least one further sensor (10) is provided for measuring at least one measured value of the device (1) for hot-dip galvanizing, in particular of the burner chamber and/or the tank interior (5) and/or the zinc melt (4),
   in particular wherein the further sensor (10) is coupled to the evaluation device (11), preferably for processing the measured value recorded by the further sensor (10) and calculating and/or deriving the wall thickness (7).
4. The device according to any one of the preceding claims, characterised in
   that the sensor (10) designed as a temperature sensor is provided, preferably on the outside, in the region of the boundary surface of the wall (8) of the galvanizing tank (3).
5. The device according to any one of the preceding claims, characterised in
   that the sensor (10) is designed as a thin-film thermocouple and/or as a sheathed thermocouple.
6. The device according to any one of the preceding claims, characterised in
   that a plurality of sensors (10) distributed over an area of the outer side (9) of the wall (8) of the galvanizing tank (3) is provided.
7. The device according to any one of the preceding claims, characterised in that the sensor (10) is provided on a carrier plate (12).
8. The device according to any one of the preceding claims, characterised in
   that the sensor (10) is provided on a wall section (13) extending in particular over the entire height and/or length of the galvanizing tank (3).
9. The device according to any one of the preceding claims, characterised in
   that the sensor (10) is provided in the intermediate space (14) between an outer tank (15) which surrounds the outer side of the galvanizing tank (3) at least in some areas.
10. The device according to any one of the preceding claims, characterised in
    that the monitoring apparatus (6) has at least one storage device (16) for storing the measured and/or calculated and/or derived values.
11. The device according to any one of the preceding claims, characterised in
    that the monitoring apparatus (6) has a display device (17) for optical and/or acoustic display,
    in particular wherein the display device (17) is coupled to the evaluation device (11) in such a way that a display signal is displayed when the wall thickness (7) of the wall (8) of the galvanizing tank (3) falls below a predetermined limit value, in particular wherein the limit value of the wall thickness (7) is in the range of 5 to 20 mm, preferably 10 to 25 mm, more preferably 15 to 20 mm and in particular at least substantially 20 mm.
12. The device according to any one of the preceding claims, characterised in
    that the monitoring apparatus (6) is coupled to a burner device (18) having at least one burner (19), in particular wherein the monitoring apparatus (6) is designed to control the burner device (18).
13. The device according to any one of the preceding claims, characterised in
    that the monitoring apparatus (6) is designed to control the gas supply and/or air supply to the burner (19) of the burner device (18) and/or to align the burner (19) with respect to the galvanizing tank (3).
14. The device according to any one of the preceding claims, characterised in
    that the sensor (10) is arranged in the region of a heat introduction zone (20) of the burner device (18).
15. A method for hot-dip galvanizing components (2), in particular using a device (1) for hot-dip galvanizing according to any one of the preceding claims, in a zinc melt (4), wherein the zinc melt (4) is located and/or arranged in a tank interior (5) formed by a wall (8) of a galvanizing tank (3),
    wherein the wall thickness (7) of the wall (8) of a galvanizing tank (3) is monitored by means of a monitoring apparatus (6) during the galvanizing operation, wherein at least one sensor (10) provided in the area of the outer side (9) of the wall (8) of the galvanizing tank (3) measures at least the temperature of the galvanizing tank (3) and an evaluation device (11) coupled to the sensor (10) processes the recorded measured value and calculates and/or derives the wall thickness (7) of the wall (8) of the galvanizing tank (3).
16. The method according to claim 15, characterised in
    that a continuous measured value acquisition takes place, and/or a further sensor (10) measures further measured values of the device (1) for hot-dip galvanizing, in particular the temperature of the zinc melt (4) and/or the temperature in the burner chamber, and wherein, preferably, the further sensor (10) is coupled to the evaluation device (11).
17. The method according to any one of the preceding claims, characterised in
    that at least one storage device (16) of the monitoring apparatus (6) stores the, in particular calculated and/or derived, values, preferably the wall thickness (7) of the wall (8) of the galvanizing tank (3) and/or that a display device (17) of the monitoring device (6) displays an optical and/or acoustic display signal,
    in particular wherein the display device (17) is coupled to the evaluation device (11) in such a way that a display signal is displayed when the wall thickness (7) of the wall (8) of the galvanizing tank (3) falls below a predetermined limit value, in particular wherein the limit value of the wall thickness (7) is in the range of 5 to 20 mm, preferably 10 to 25 mm, more preferably 15 to 20 mm and in particular at least substantially 20 mm.
18. The method according to any one of the preceding claims, characterised in
    that the monitoring apparatus (6) is coupled to a burner device (18) having at least one burner (19), wherein the monitoring apparatus (6) controls the burner device (18).
19. The method according to any one of the preceding claims, characterised in
    that the monitoring apparatus (6) controls the gas supply and/or the air supply and/or the alignment of the burner (19) of the burner device (18).

Images