Controlling the moisture content of tissue paper is a critical aspect in the manufacturing process, as it directly impacts the quality, strength, and usability of the final product. As a leading supplier of Tissue Paper Making Machines, we understand the importance of this factor and have developed advanced technologies to ensure precise moisture control. In this blog, we will delve into the mechanisms and strategies employed by our machines to achieve optimal moisture levels in tissue paper.
The Significance of Moisture Content in Tissue Paper
The moisture content of tissue paper plays a pivotal role in determining its physical properties. If the moisture content is too high, the paper may become weak, prone to tearing, and may develop mold or mildew during storage. On the other hand, if the moisture content is too low, the paper becomes brittle, loses its softness, and may generate excessive static electricity. Therefore, maintaining the ideal moisture content is essential for producing high - quality tissue paper that meets the expectations of consumers.
Initial Pulp Preparation
The journey of moisture control begins at the very first stage of the tissue paper manufacturing process - pulp preparation. Pulp is the raw material for tissue paper, and it typically contains a significant amount of water. Our Tissue Paper Making Machines are equipped with advanced pulp screening and cleaning systems that can remove impurities from the pulp while also adjusting its consistency.
The consistency of the pulp refers to the ratio of dry fiber to water in the pulp mixture. By precisely controlling the pulp consistency, we can set the initial moisture level for the subsequent stages of the manufacturing process. For example, a higher pulp consistency means less water is present in the mixture, which can reduce the amount of water that needs to be removed later.
Forming Section
In the forming section of the tissue paper making machine, the pulp is deposited onto a moving wire mesh to form a wet web of paper. This is a crucial stage where the initial dewatering process begins. The wire mesh allows water to drain through it, leaving behind a layer of fibers that gradually form the paper structure.
Our machines use a combination of gravity and vacuum suction to enhance the dewatering efficiency. Gravity causes the water to naturally drain from the pulp, while vacuum boxes located beneath the wire mesh create a negative pressure that sucks the water out more rapidly. The intensity of the vacuum can be adjusted according to the desired moisture content of the wet web. By carefully controlling the vacuum pressure and the speed of the wire mesh, we can ensure that the wet web has a consistent moisture level across its entire width and length.
Pressing Section
After the forming section, the wet web enters the pressing section. Here, the web passes through a series of press rolls that apply pressure to squeeze out more water. The press rolls are designed with specific surface characteristics and hardness to optimize the dewatering process.
In addition to mechanical pressure, our machines also use steam - heated press rolls in some cases. The steam provides additional heat energy, which helps to evaporate some of the water in the wet web. This combination of mechanical squeezing and steam - assisted evaporation can significantly reduce the moisture content of the paper. The pressure applied by the press rolls and the temperature of the steam can be precisely controlled to achieve the desired moisture reduction.
Drying Section
The drying section is where the majority of the water removal occurs. Our Tissue Paper Making Machines are equipped with state - of the - art drying cylinders or Yankee dryers. These dryers are large, rotating cylinders that are heated internally, usually by steam.
As the wet web passes over the heated surface of the drying cylinders, the heat causes the water in the paper to evaporate. The temperature of the drying cylinders can be accurately controlled to ensure that the evaporation process occurs at an optimal rate. A higher temperature can lead to faster evaporation, but it also needs to be balanced to avoid over - drying the paper, which can make it brittle.
In addition to the temperature, the contact time between the paper and the drying cylinders is also an important factor. By adjusting the speed of the paper web and the number of drying cylinders, we can control the overall drying time and, consequently, the final moisture content of the paper.
Moisture Sensing and Feedback System
To ensure that the tissue paper has the exact moisture content required by the customer, our machines are equipped with advanced moisture sensing devices. These sensors are strategically placed at various points along the production line, such as at the exit of the drying section.
The moisture sensors continuously measure the moisture content of the paper in real - time and send the data to a control system. The control system then compares the measured moisture content with the set target value. If there is a deviation, the control system can automatically adjust the operating parameters of the machine, such as the temperature of the drying cylinders, the pressure in the pressing section, or the vacuum level in the forming section. This closed - loop feedback system ensures that the moisture content of the tissue paper remains within the specified tolerance range throughout the production process.
Re - humidification (if necessary)
In some cases, the tissue paper may be dried to a moisture content that is lower than the desired level. This can happen due to variations in the raw materials, environmental conditions, or production speed. To address this issue, our machines can be equipped with re - humidification systems.
The re - humidification system sprays a fine mist of water onto the paper surface in a controlled manner. The amount of water sprayed can be adjusted based on the measured moisture deficit. This allows us to bring the moisture content of the paper back to the optimal level, ensuring its softness and flexibility.
Other Related Machines and Their Role in Moisture Control
In addition to the main Tissue Paper Making Machine, we also offer a range of complementary machines that can further enhance the moisture control and overall quality of the tissue paper. For example, our Toilet Paper Roll Making Machine is designed to convert the large rolls of tissue paper into smaller, consumer - friendly rolls. During this process, the machine can also monitor and adjust the moisture content of the paper to prevent any issues during the rolling and packaging stages.
Our Bandsaw Cutting Machine is used to cut the large tissue paper rolls into the desired sizes. By maintaining the proper moisture content, the paper can be cut cleanly without fraying or tearing. And our Tissue Paper Wrapping Machine can ensure that the wrapped tissue paper maintains its moisture level during storage and transportation, thanks to its air - tight packaging capabilities.
Conclusion
Controlling the moisture content of tissue paper is a complex but essential process in the tissue paper manufacturing industry. Our Tissue Paper Making Machines are designed with advanced technologies and precise control systems to ensure that every roll of tissue paper produced meets the highest quality standards in terms of moisture content.
If you are in the market for high - quality Tissue Paper Making Machines that can provide excellent moisture control, we invite you to contact us for more information. Our team of experts is ready to assist you in selecting the right machine for your specific production needs and to provide you with comprehensive after - sales support. Let's work together to produce the best - quality tissue paper in the market.
References
- "Handbook of Pulp and Paper Technology", Second Edition, by G.A. Smook
- "Papermaking Science and Technology", Volume 1: Pulping, by K.G. Aarne and others
- Technical reports from our in - house research and development department on Tissue Paper Making Machine technologies.