The Paper Machine is a very large piece of machinery. A typical machine is about the length of two football pitches and around 4 metres wide. It can run up to speeds of 2000 m per minute - or 60 miles per hour! The machine itself consists of 7 distinct sections. The flow box, wire, press section, drier section, size press, calendar and reeling up.
Suspension at the headbox
After dilution and sorting in the constant part, the suspension of fibres, process materials and water has to be led to the wire part uniformly distributed across the width of the paper web. In principle, the speed at which the suspension exits from the headbox onto the wire has to be equal to the speed of the wire on which the sheet is formed. To achieve this, pressure is applied to the suspension in the headbox, in order to accelerate it to the wire speed. Apart from that, turbulence is generated just before the exit point of the headbox to avoid harmful flock formation.
Sheet formation in the wire section
Once the suspension has left the headbox and comes into contact with the wire, the paper fibres move to the wire as a result of their natural flow resistance, thus forming a layer of fibres on the wire which accumulates towards the top of the stock. At the same time, water drains away at the bottom, and this combination of processes leads to two different forms of sheet formation, depending on the freedom of motion of the fibres in the suspension: through filtration and by means of thickening.
De-watering in the press section
After formation of the sheet, a process which determines the most important sheet properties, the paper sheet has to be further drained and compressed. In this next phase, mechanical pressure exerted vertically to the sheet surface is used to further increase the proportion of dry content. In the press section, the web runs between a series of rolls which exert specifically set amounts of pressure. The water pressed out of the paper is absorbed by felts and transported off.
In recent years, shoe presses have been developed to increase the efficiency of the traditional roll presses. In these press units, one of the rolls is replaced by a hydraulically pressed shoe. This creates a bigger press nip, which makes the process more effective
Dryer section
When the paper leaves the press section, it has a dry content of up to 50-55%. Now, the remaining water has to be removed by vaporisation. The most common type of paper drying is contact drying on cylinders heated with vapour. Here, the heat energy is transferred from the outside walls of the drying cylinders to the paper surface by direct contact. The dryer section consists of a succession of drying cylinders and the paper web is transported over and between these cylinders, the paper alternately making contact with the upper and the lower side. Drying takes place in different phases. In the short, first phase, only heat is transferred to the paper. There is no vaporisation. This takes place during the second phase, when the wet paper starts to convey its humidity to the surrounding air. In other words, the water contained in the paper starts to evaporate. In the third phase, the paper surface has already been dried to the maximum extent, and heat transmission into the dry paper stimulates vaporization inside the paper.
End group
After conclusion of the drying process, the paper is often subjected to glazing in machine calenders. Besides machine calenders, which use steel rolls, there are also soft calenders, consisting of paired rolls where one is made of steel and the other one is coated with a soft, plastic material. This produces a better overall glazing effect and eliminates the problem of so-called black glazing. At the end of the machine, the paper is taken up on steel cores, the so-called tambours. Most paper machines use pope rollers. The tambour presses against the big pope roller and takes up the paper in
Suspension at the headbox
After dilution and sorting in the constant part, the suspension of fibres, process materials and water has to be led to the wire part uniformly distributed across the width of the paper web. In principle, the speed at which the suspension exits from the headbox onto the wire has to be equal to the speed of the wire on which the sheet is formed. To achieve this, pressure is applied to the suspension in the headbox, in order to accelerate it to the wire speed. Apart from that, turbulence is generated just before the exit point of the headbox to avoid harmful flock formation.
Sheet formation in the wire section
Once the suspension has left the headbox and comes into contact with the wire, the paper fibres move to the wire as a result of their natural flow resistance, thus forming a layer of fibres on the wire which accumulates towards the top of the stock. At the same time, water drains away at the bottom, and this combination of processes leads to two different forms of sheet formation, depending on the freedom of motion of the fibres in the suspension: through filtration and by means of thickening.
De-watering in the press section
After formation of the sheet, a process which determines the most important sheet properties, the paper sheet has to be further drained and compressed. In this next phase, mechanical pressure exerted vertically to the sheet surface is used to further increase the proportion of dry content. In the press section, the web runs between a series of rolls which exert specifically set amounts of pressure. The water pressed out of the paper is absorbed by felts and transported off.
In recent years, shoe presses have been developed to increase the efficiency of the traditional roll presses. In these press units, one of the rolls is replaced by a hydraulically pressed shoe. This creates a bigger press nip, which makes the process more effective
Dryer section
When the paper leaves the press section, it has a dry content of up to 50-55%. Now, the remaining water has to be removed by vaporisation. The most common type of paper drying is contact drying on cylinders heated with vapour. Here, the heat energy is transferred from the outside walls of the drying cylinders to the paper surface by direct contact. The dryer section consists of a succession of drying cylinders and the paper web is transported over and between these cylinders, the paper alternately making contact with the upper and the lower side. Drying takes place in different phases. In the short, first phase, only heat is transferred to the paper. There is no vaporisation. This takes place during the second phase, when the wet paper starts to convey its humidity to the surrounding air. In other words, the water contained in the paper starts to evaporate. In the third phase, the paper surface has already been dried to the maximum extent, and heat transmission into the dry paper stimulates vaporization inside the paper.
End group
After conclusion of the drying process, the paper is often subjected to glazing in machine calenders. Besides machine calenders, which use steel rolls, there are also soft calenders, consisting of paired rolls where one is made of steel and the other one is coated with a soft, plastic material. This produces a better overall glazing effect and eliminates the problem of so-called black glazing. At the end of the machine, the paper is taken up on steel cores, the so-called tambours. Most paper machines use pope rollers. The tambour presses against the big pope roller and takes up the paper in
| Company Name | Zulanartpapermanufacturers |
|---|---|
| Business Type | Manufacturer, Distributor/Wholesaler |
| Main Products | Art Paper, A4 Copier Paper |
| Total No. Employees | 51 - 100 People |
| Company Certification | ISO 14001:2004 ISO 17799 |
| Year Established | 1999 |
| Contract Manufacturing | OEM Service Offered Design Service Offered |
| City | udon thani |
| Province/State | udon thani |
| Country/Region | Thailand |
| Contact Person | Mr. Zulan Art Paper |
| Telephone | 6***********9 View all, please login |
| Fax | 66 |
| Street Address | robeang road t, nong bua mueang |
| Zip Code | 10205 |
| sell123 URL | http://www.sell123.org/company/Thailand/213534.htm |
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