Method for detecting a fibrous web tear in a drying section of a machine for producing the fibrous web and a dryer fabric for performing the method
a drying section and fibrous web technology, applied in the field of fibrous web tear detection in the drying section of the machine for producing fibrous web, can solve the problems of unsuitable light barriers, unreliable, and inability to differentiate clearly between fibrous web and dryer fabric, so as to reduce production costs, reduce unit costs, and high reliability
Inactive Publication Date: 2008-05-29
VOITH PATENT GMBH
View PDF6 Cites 6 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Benefits of technology
[0013]By using at least one characteristic color pattern, which is less vulnerable to soiling of the dryer fabric or discolorations of the fibrous web and / or the dryer fabric, the reliability of the fibrous web tear detection is notably improved, in particular with regard to the conventional methods.
[0025]The detection of the fibrous web tear takes place, according to the present invention, by using various measurement methods: for example taking a spot measurement with a laser beam, a light beam or the like, a line measurement with a line camera or the like, and / or an area measurement with a CCD camera or the like. All measurement methods are characterized by high reliability and good usability even in difficult environments.
Problems solved by technology
However, light barriers are unsuitable in situations in which the fibrous web rests on a skin acting as a web carrier, for example on a forming mesh, a press felt or a dryer fabric.
A drawback of the color detection system is that it becomes more and more unreliable as the color difference between the fibrous web and the dryer fabric decreases.
Here it is no longer possible to differentiate clearly between the fibrous web and the dryer fabric.
The former leads to an unnecessary stoppage of production and hence to financial loss for the plant operator, the latter runs the risk of causing damage to the machine.
Furthermore, dryer fabrics can become severely soiled the longer they are used, as the result of which the actual color of the dryer fabric is covered by dirt deposits.
In such cases also it has been discovered that a color detection system no longer works reliably.
It has been discovered that pseudo-structure detection systems likewise do not work reliably.
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0038]Referring now to the drawings, and more particularly presented, schematically in FIG. 2, is a side view of a detail of a drying section 2 of a machine, generally designated by 1, for producing a fibrous web 3. Within machine 1, drying section 2 performs in a known manner the function of removing moisture from a produced and / or processed fibrous web 3, meaning the function of drying it.
[0039]The drying is done in the example shown in FIG. 2 by way of contact drying, whereby fibrous web 3, being fed from the left in the drawing, is dried by direct contact with a plurality of drying cylinders 4 on the one hand and an endless dryer fabric 5 circulating around drying cylinders 4 on the other hand.
[0040]Presented in FIG. 2 are two dryer fabrics 5 in their complete path of rotation, whereby each of dryer fabrics 5 circulates respectively around one group of drying cylinders 4. To be more precise, each dryer fabric 5 undulates in the region of drying cylinders 4, whereby at the wave p...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
This invention relates to a method for detecting a tear in a fibrous web (3) in a drying section (2) of a machine (1) for producing the fibrous web (3), whereby the fibrous web (3) is passed through the drying section (2) by way of at least one dryer fabric (5). The tear is detected by at least one web tear detection device (8) and a cut-off apparatus (9) for the fibrous web (3) is activated by the web tear detection device (8). Use is made of a dryer fabric (5) with at least one characteristic color pattern (10) which is reliably detected by the web tear detection device (8) in the event of a tear in the fibrous web (3). In addition the present invention relates to a dryer fabric (5) for a drying section (2) of a machine (1) for producing a fibrous web (3).
Description
BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates to a method for detecting a fibrous web tear in a drying section of a machine for producing the fibrous web, whereby the fibrous web is passed through the drying section by way of at least one dryer fabric, whereby the tear is detected by at least one web tear detection device and whereby a cut-off apparatus for the fibrous web is activated by the web tear detection device. In addition the invention relates to a dryer fabric for a drying section of a machine for producing a fibrous web, in particular for performing the inventive method.[0003]2. Description of the Related Art[0004]During the production of all paper grades, formed essentially from fibrous suspensions, the fast and reliable detection of tears in the fibrous web during its production is extremely important in order to prevent damage to parts of the machine used to produce the fibrous web.[0005]At points in which the fibrous web is in ...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More IPC IPC(8): D21F7/12
CPCD21F7/04
Inventor BAUER, ARMINKLING, ROBERT
Owner VOITH PATENT GMBH