Do You Know The Application of Spray Nozzle in Paper Machine?
Spray Nozzle Applied in Paper Machine
Spray nozzle is widely used in various applications of pulp and paper industry. In the papermaking process, there are nozzles present in every step of the production process, including the headbox, forming section , press section, dryer section, and reel section. The effectiveness of spray nozzle use directly determines the quality of paper produced by the paper mill and the service life of various felt and wire. Improper selection may also lead to paper diseases such as curling, edge bleeding, wrinkling, needle line, etc. Below is a brief introduction to the application of several spray nozzles in papermaking:
Edge cutting water needle nozzle
Edge cutting water needle is a widely used technology in the paper industry, this spray nozzle is mainly used for edge cutting and trimming of paper. It cuts and cuts the edges of the paper through high-pressure water flow to achieve precise and smooth edge effects. Due to the fluid properties of water and high-pressure spraying, edge cutting water needles can achieve high-speed, efficient, and precise cutting and trimming of paper edges. In addition, this spray nozzle can reduce pulp loss and improve papermaking efficiency and quality. Needle type nozzles are usually used, which require operation under high pressure conditions. In order to improve the service life of the spray nozzle, high-pressure resistant and wear-resistant material spray cores are usually used.
Starch coating
Starch is one of the most important raw materials in papermaking, and it can improve the wet end stability of paper during the papermaking process. Starch coating can enhance the strength and durability of paper, improve its gloss and smoothness, enhance its printing performance, improve its moisture resistance, and increase its density and thickness. The uniformity of starch coating is very important. The starch solution can be evenly atomized through the spray nozzle by spray. Hollow cone spray nozzle has excellent atomization performance and can be used for starch coating.
Chemical defoaming
In the whole process of pulp and paper industry, a series of operations after steaming, boiling and discharging, such as washing, screening, bleaching, concentration, pulp supply system, surface sizing, coating, black liquor recovery, etc., are all affected to varying degrees by foam, interfering with normal production, reducing paper quality, and even making production impossible in serious cases. The nozzle can evenly spray chemical defoamers on the surface of the pulp, allowing them to quickly diffuse and adsorb onto the surface of the bubbles, thereby changing the surface tension and stability of the bubbles, causing them to quickly rupture and dissipate, thus achieving the effect of defoaming. The nozzle can achieve precise control and adjustment of chemical defoamers, optimizing their defoaming effect during the pulping process, thereby improving the efficiency and product quality of pulping. Solid cone nozzles, spiral nozzles, etc. are usually used.
Paper machine clothing cleaning
paper making felt and wire cleaning is an important part of the paper industry, mainly used to clean press felt, forming fabric and dryer fabric to maintain their cleanliness and work efficiency. Common cleaning spray nozzles include high-pressure spray nozzles and fan-shaped spray nozzles, which can form high-pressure straight or fan-shaped liquid column flows, effectively removing fibers and impurities from the press felt. These spray nozzles are typically made of 316 stainless steel and ceramic materials to withstand high pressures up to 140 bar and feature anti clogging design. During installation, attention should be paid to the distance between the spray nozzle and the paper making press felt and wire (recommended 30 to 120mm) and the parallelism between the spray rod and the guide roller to ensure cleaning effectiveness.
Low pressure cleaning and lubrication:
Generally, fan-shaped
spray nozzles are used, with a pressure of 3 to 5 bar. The correct selection of the model has a direct impact on water consumption and blockage. The correct selection of spray nozzles has a significant impact on water conservation, energy efficiency, and spraying effectiveness.
Post processing humidification:
Humidity control in the paper industry is actually about controlling the loss of moisture from paper after drying. Once paper is produced and rolled into a cylindrical shape, it will be in contact with the surrounding environment for a considerable amount of time at the end of the papermaking equipment. The moisture on the surface of the paper exposed to the outside will change with the surrounding humidity, which may cause problems in the cutting and packaging processes. The workshop of the paper mill needs to control the humidity at 45%~60% RH to humidify and cool down, in order to ensure the quality of the paper. Not only that, humidification can also reduce the dust concentration in the environment to a certain extent and alleviate the dust flying phenomenon caused by static electricity. Usually, fine atomization
spray nozzles, automatic air atomization spray nozzles, and air atomization nozzles are used in this process to control temperature and humidity.
In short, the spray nozzles play an extremely important role in the papermaking process, and selecting the right nozzle for a specific application is the key to achieving optimal results. Choosing the right spray nozzles can effectively ensure product quality, extend equipment lifespan, and avoid waste and increased operating costs caused by improper nozzle selection.
