MONITORING A FLAME APPLICATION DEVICE

Description

[0001] The present invention relates in general to the monitoring of a flame treatment device and in particular to a substrate treatment plant with a flame treatment device and first and second substrate monitoring units.

[0002] Flame treatment can be used in various industrial processes, where the surface of a substrate is exposed to a gas flame, operated with excess oxygen, for a defined process time. For example, a gas flame can be used to improve adhesion to polyolefin substrates (the so-called Kreidl process). In industrial processes, the substrates are usually automatically fed to the flame for a few seconds. However, if the process time is not adhered to or an incorrect time is selected, overheating can occur, and in the case of flammable substrates, such as those made of plastic, the substrate can ignite, posing a risk of fire in the corresponding system. Against this background, US Patent 2021 / 039132 A1 discloses a temperature monitoring unit for a substrate treatment system with a flame treatment device.A transport device moves substrate carriers containing substrates through the flame treatment device. A substrate monitoring unit records the temperature of the substrates after they leave the flame zone. A control unit controls the flame treatment device based on the substrate temperature.

[0003] It is therefore an object of the present invention to provide an improved monitoring mechanism that reliably prevents the occurrence of a fire without unnecessarily stopping or interrupting the corresponding process. This object is achieved by a substrate treatment system according to claim 1 and a method for flame-treating substrates according to claim 11.

[0004] The present invention is essentially based on the idea of ​​providing two substrate monitoring units that monitor different process parameters in order to enable the occurrence of fires to be efficient, effective and less susceptible to interference.

[0005] The substrate treatment system according to the invention comprises a flame treatment device for treating substrates in a flame zone. The flame treatment device can be any flame treatment device known from the prior art. The substrate treatment system further comprises a transport device for transporting a substrate carrier containing substrates through the flame treatment device. The transport device can have one or more transport units for transporting the substrate carrier. For example, a first transport unit can be provided for transporting the substrate carrier through the flame zone and a second transport unit for transporting the substrate carrier beyond the flame zone. The transport device can also have further transport units for transporting the substrate carrier to the flame treatment device.

[0006] According to the invention, a first substrate monitoring unit is provided, which is suitable and configured to monitor the movement of the substrate carrier through the flame treatment device with regard to its transport speed and / or its residence time in the flame zone. Furthermore, according to the invention, a second substrate monitoring unit is provided, which is suitable and configured to monitor the substrates in the substrate carrier after they have left the flame zone with regard to their temperature. The substrate treatment system also includes a control unit, which is suitable and configured to switch off the flame treatment device and, in particular, its flame, if the first substrate monitoring unit detects an excessively low transport speed and / or an excessively long residence time of a substrate carrier in the flame zone.The control unit is also suitable and equipped to stop the transport of the substrate carriers through the flame device and in particular through the flame area if the second substrate monitoring unit detects an excessively high temperature of a substrate.

[0007] This dual monitoring system offers several advantages. The first substrate monitoring unit allows for simple yet reliable monitoring and, as a rule, prevents substrates from being overheated or heated to excessive temperatures because the flame is extinguished before it can act on the substrates in the substrate carrier for too long. However, since ignition could theoretically still occur (for example, if substrates with a lower flash point are incorrectly loaded), the second substrate monitoring unit ensures that substrates with excessively high temperatures are identified in every case and their further transport into sensitive areas of the substrate treatment system (e.g., downstream treatment units for painting) is reliably prevented. In principle, a substrate treatment system with only the second substrate monitoring unit would also be functional.However, this would have the disadvantage of triggering fires more frequently, which, due to the resulting consequences (triggering a fire suppression process, etc.), would be detrimental to the continuous operation of the substrate treatment plant. The short-term shutdown of the flame treatment device triggered by the first substrate monitoring unit is significantly less problematic in this respect and can prevent a fire from occurring in up to 99 percent of cases. Against this background, the combination of the first and second substrate monitoring units is particularly safe and effective, while simultaneously minimizing the impact on the process flow as much as possible.

[0008] The first substrate monitoring unit preferably has at least two, more preferably at least three, sensors that are suitable and configured to detect the presence of a substrate carrier at at least two, preferably at least three, positions in the flame device. Since, under normal operating conditions, the substrate carriers can be assumed to move at a constant speed, it is generally sufficient to know, for example, the time of entry and exit of the substrate carrier into and out of the flame zone to determine the transport speed at which the substrate carrier moved through the flame zone. If the substrate carrier is not detected at the end of the flame zone after the usual residence time or a predetermined limit time, the flame is switched off to prevent further heating of the substrates in the substrate carrier.To ensure maximum system redundancy, it is preferable to use at least three sensors. Suitable sensors include, for example, photoelectric sensors and photoelectric barriers, such as the G2S series (e.g., GTB2S-F5311) or the W2S-2 series (GTB2S-F5311) from the manufacturer Sick AG.

[0009] The second substrate monitoring unit preferably comprises at least one, more preferably at least two, temperature measuring unit(s). These are preferably suitable for measuring the temperature of the substrates after they leave the flame zone with an accuracy of ±10° Kelvin. This measurement should preferably take place within the time it takes for the substrates to pass the respective temperature measuring unit, i.e., typically within a few seconds, so that fast-responding temperature measuring units such as pyrometers can preferably be used.

[0010] The transport of the substrate carriers by the flame treatment device is preferably controlled such that the substrate (or the substrate carrier containing it) is stopped in a defined area of ​​the substrate treatment system if the substrate reaches an excessively high temperature. Firstly, this defined holding area should be located in a part of the substrate treatment system where a potentially burning substrate can cause minimal damage, for example, in a fire-resistant environment. Secondly, it is preferred that the substrate treatment system also includes a flame detector capable of detecting a flame in this defined area. This flame detector could, for example, be an approved fire alarm and / or an approved fire monitoring system.This additional flame detector is advantageous because, as explained above, the second substrate monitoring unit must perform a relatively rapid temperature measurement, which can be prone to error. Before initiating, for example, an extinguishing process, it should be sufficiently certain that a fire hazard actually exists or that a substrate is already burning. This can be achieved with the additional flame detector, which precisely detects the presence of a flame in the defined area where the substrate carrier has been stopped. However, this flame detector serves only as an additional, and preferably officially certified, safety device that is only activated if the second substrate monitoring unit has previously detected an excessively high substrate temperature.

[0011] The control unit is further preferably suitable and configured to request a manual extinguishing process and / or to initiate an automatic extinguishing process if the flame detector detects a flame in the defined area. For example, an audible or visual fire alarm can be triggered and / or the activation of a fire extinguishing system (e.g., sprinkler system, CO2 extinguishing system, inert gas extinguishing system) can be initiated by the control unit.

[0012] As previously mentioned, the transport device can have a first transport unit for moving the substrate carriers through the flame device at a first speed and a second transport unit for moving the substrates at a second speed beyond the flame device or its flame zone, whereby the first and second speeds can differ. This allows a substrate carrier to be stopped behind the flame device (for example, in the defined area to detect a flame) without interrupting the loading of the flame device, since different transport units are available for this purpose. In this case, the control unit is specifically designed and configured to stop the second transport unit of the transport device if the second substrate monitoring unit detects an excessively high temperature of a substrate.

[0013] The control unit is furthermore suitable and configured to switch off the flame treatment device if the second substrate monitoring unit detects an excessively high substrate temperature. It is also preferred that the control unit is suitable and configured to stop the loading of the flame treatment device if the second substrate monitoring unit detects an excessively high substrate temperature. Preferably, the substrate carriers are stopped in such a way that the flame treatment device is unloaded before stopping.

[0014] The present invention can, in principle, be used in any substrate treatment system that requires a flame treatment device. For example, the substrate treatment system can further comprise one or more of the following units: painting unit, cleaning unit, in particular a brush cleaning unit, coating unit, in particular a PVD or CVD coating unit, bonding unit, printing unit.

[0015] The present invention further relates to a method for flame-treating substrates using the substrate treatment system discussed above, wherein the method comprises the following steps: continuously transporting several substrate carriers through the flame-treating device, wherein the substrates of each substrate carrier are flame-treated in the flame-treating device; monitoring the substrate carriers with regard to their transport speed and / or their residence time in the flame zone of the flame-treating device; monitoring the substrates after leaving the flame zone with regard to their temperature; switching off the flame-treating device if an excessively low transport speed and / or an excessively long residence time of a substrate carrier in the flame zone is detected; and stopping the substrate carrier if an excessively high temperature of a substrate is detected after leaving the flame zone.Preferably, a flame measurement is performed in a defined area where a substrate with an excessively high temperature has been stopped. If a flame is detected, a manual extinguishing process is preferably requested and / or an automatic extinguishing process is initiated. If an excessively high temperature of a substrate is detected after it has left the flame zone, the flame device, and in particular its flame, is preferably switched off. If an excessively high temperature of a substrate is detected after it has left the flame zone, the loading of the flame device is also preferably stopped. The substrate carriers are preferably stopped in such a way that the flame device is unloaded before stopping. The substrates preferably consist of plastic, particularly preferably polyolefin.

[0016] A particularly preferred embodiment of the present invention is described below with reference to the Figure 1 described in more detail.

[0017] Figure 1Figure 1 schematically shows a substrate treatment system with a flame treatment device 1 for treating substrates, which has a flame zone. The substrates located in a substrate carrier 6 are transported through the flame treatment device 1 by means of a transport device. In the illustrated embodiment, the transport device has a first transport unit 2a and a second transport unit 2b, the direction of movement of which is indicated by the arrow. A first substrate monitoring unit 3 is also provided, which is suitable for monitoring the movement of the substrate carrier 6 through the flame treatment device 1 with regard to its transport speed and / or its dwell time in the flame zone. In the illustrated embodiment, the first substrate monitoring unit 3 has three sensors that are suitable for detecting the presence of the substrate carrier 6 at three positions in the flame treatment device 1.A second substrate monitoring unit 4 is provided behind the flame zone of the flame device. This unit is capable of monitoring the temperature of the substrates in the substrate carrier 6 after they have left the flame zone. If the second substrate monitoring unit 4, which in the illustrated embodiment includes a temperature measuring unit, detects an excessively high temperature of a substrate, the transport of the substrate carriers through the flame device 1 is stopped. In the illustrated embodiment, this is achieved by stopping the second transport unit 2b, while the first transport unit 2a of the transport device can generally continue operating, so that the flame treatment does not have to be interrupted immediately.The stopping of the substrate carrier 6 on the second transport unit 2b is controlled in such a way that the substrate with excessively high temperature, or the substrate carrier containing it, is stopped in a defined area of ​​the substrate treatment system, so that a flame can be detected in this defined area by the flame detector 5. If the flame detector 5 does not detect a flame, the operation of the second transport unit 2b can be resumed. Otherwise, appropriate measures are initiated, for example, a manual extinguishing process is requested or an automatic extinguishing process is triggered.

[0018] Stoppers 7 are provided at the beginning of the first transport unit 2a and at the end of the second transport unit 2b.

Claims

1. A substrate treatment system comprising: a flame treatment device (1) for flame treating substrates comprising a flame zone; a transport device (2a, 2b) for transporting a substrate carrier (6) with substrates through the flame treatment device (1); a first substrate monitoring unit (3) which is suited to monitor the movement of the substrate carrier (6) through the flame treatment device (1) with respect to its transport speed and / or its dwell time in the flame zone; a second substrate monitoring unit (4) which is suited to monitor the substrates in the substrate carrier (6) with respect to their temperature after they exit the flame zone; and a control unit, i) which is adapted to switch off the flame treatment device (1) if the first substrate monitoring unit (3) detects too low a transport speed and / or too long a dwell time of a substrate carrier (6) in the flame zone, and ii) which is adapted to stop the transport of the substrate carriers (6) through the flame treatment device (1) if the second substrate monitoring unit (4) detects that the temperature of a substrate is too high.

2. The substrate treatment system of claim 1, wherein the first substrate monitoring unit (3) comprises at least two, preferably at least three sensors, which are suited to detect the presence of a substrate carrier (6) at at least two, preferably at least three positions in the flame treatment device.

3. The substrate treatment system of claim 1 or 2, wherein the second substrate monitoring unit (4) comprises at least one, preferably at least two temperature measuring unit(s), wherein the temperature measuring unit(s) is / are preferably suited to measure the temperature of the substrates after they exit the flame zone, preferably within the time period in which the substrates pass the relevant temperature measuring unit, with an accuracy of + / - 10° K.

4. The substrate treatment system of any one of the preceding claims, wherein stopping the substrate carriers (6) is controlled in such a way that the substrate showing too high a temperature is stopped within a defined area of the substrate treatment system.

5. The substrate treatment system of claim 4, wherein the substrate treatment system further comprises a flame detector (5) which is suited to detect a flame in the defined area.

6. The substrate treatment system of claim5, wherein the control unit is suited to request a manual fire extinguishing process and / or to initiate an automatic fire extinguishing process if the flame detector detects a flame in the defined area.

7. The substrate treatment system of any one of the preceding claims, wherein the transport device comprises a first transport unit (2a) for transporting the substrate carriers (6) at a first speed through the flame zone (1) and a second transport unit (2b) for transporting the substrate carriers onward at a second speed after they pass the flame zone.

8. The substrate treatment system of any one of the preceding claims, wherein the control unit is further suited to switch off the flame treatment device (1) if the second substrate monitoring unit (4) detects that the temperature of a substrate is too high.

9. The substrate treatment system of any one of the preceding claims, wherein the control unit is further suited to stop the loading of the flame treatment system (1) if the second substrate monitoring unit (4) detects that the temperature of a substrate is too high.

10. The substrate treatment system of any one of the preceding claims, wherein stopping the substrate carriers in step ii) takes place in such a way that the flame treatment system (1) is unloaded before the substrate carriers are stopped.

11. A method for flame treating substrates by means of the substrate treatment system of any one of the preceding claims wherein the method comprises the following steps: continuous transport of a number of substrate carriers through the flame treatment device (1), wherein the substrates of each of the substrate carriers (6) are flame treated in the flame treatment device (1); monitoring the substrate carriers (6) with respect to their transport speed and / or their dwell time in the flame zone of the flame treatment device (1); monitoring the substrates with respect to their temperature after they exit the flame zone; switching off the flame treatment device (1) if it is detected that a substrate carrier (6) shows too low a transport speed and / or too long a dwell time in the flame zone; and stopping the substrate carriers (6) if it is detected that the temperature of a substrate is too high after it exits the flame zone.

12. The method of claim 11, wherein the method further comprises: flame measuring / flame detection in a defined area in which a substrate showing too high a temperature is stopped, wherein the method preferably further comprises: requesting a manual fire extinguishing process and / or initiating an automatic fire extinguishing process if a flame is detected.

13. The method of any of claims 11 to 12, wherein the method further comprises: switching off the flame treatment device (1) if it is detected that the temperature of a substrate is too high after it exits the flame zone.

14. The method of any of claims 11 to 13, wherein the method further comprises: stopping the loading of the flame treatment device (1) if it is detected that the temperature of a substrate is too high after it exits the flame zone.

15. The method of any of claims 11 to 14, wherein stopping the substrate carriers (6) takes place in such a way that the flame treatment device is unloaded before the substrate carriers are stopped.