Talking about the application of shoe press

With the rapid development of the paper industry, the high speed of the paper machine speed has higher requirements for the dewatering effect of the press section. The use of shoe presses greatly improves the dewatering performance of the paper machine at high speeds.

The shoe press is an instantaneous dynamic dewatering of a roll press and is changed to a long pressurization dewatering under a static pressure, which is a wide nip press. Compared to conventional presses, the press nip of the shoe press is several times that of a conventional press nip. Due to this feature, the residence time of the sheet in the shoe nip is several times that of the conventional nip under the same speed conditions. At the same time, shoe presses can obtain higher line pressures, much higher than traditional roll line pressures. Therefore, the shoe press helps to increase the dewatering efficiency of the paper sheet, and is more conducive to the solidification of the paper web, so that the paper web can obtain better strength before drying, so that the press section can obtain better running performance. And the water content in the web is reduced, which also greatly saves steam consumption.

The shoe press is mainly composed of a shoe roll, a back pressure roll, a load lock, and some auxiliary components. The main components of the boot roller include a shoe plate, a rotating head, a cross beam, a bearing seat, etc. The soft material for the boot roller cover is a boot cover. The roller core of the shoe roll is stationary instead of rotating. The entire shoe roll itself does not have a drive device; the outer core of the roll core is set with a sleeve of soft material—the shoe cover, and the shoe cover is mounted on the special bearing of the roll core through the press plate. The shoe cover is The rotating part; The shoe is the core part of the shoe press. It is connected to a special hydraulic cylinder at one end. They are fixed together on the beam inside the shoe roller. Under the action of the cylinder, the shoe presses the back pressure roller. Hydraulic oil is injected through a specially made oil hole in the pressure shoe into a recessed groove between the pressure shoe and the shoe cover. Due to the unique design of these recessed grooves, a layer of high-pressure oil film is created between the shoe and the shoe cover, and the role of the high pressure oil film static and hydrodynamic effects is to support, lubricate, and cool the shoe and the boot. This fluid-lubricated condition allows the friction to be low in power consumption and extremely slight in wear, thereby greatly extending the life of the boot while reducing energy consumption.

The boot cover is mainly composed of polyamide and polyurethane. The polyamide has good alkali resistance and acid resistance. The polyurethane has good acid and alkali resistance at a certain temperature. In order to further improve the dehydration efficiency, the surface of the shoe cover will generally be designed with a groove shape. According to the groove shape, it can be divided into "U" type and "ladder" groove cover sets. The boot is a consumable part. As long as it produces a tiny hole, it is fatal to it. Usually cause the boot to advance down the machine mainly for the following reasons: 1, the damage caused by the hard object into the boot pressure; 2, the boot material due to continuous bending and fatigue caused by cracks; 3, the pressure on the boot or the outside world to small The burr causes stratification due to causes such as pressing shoes or boots, etc.; 4. Severe wear due to abnormal causes; 5. Causes of the boot cover itself. For the maintenance of boots, the most important thing is the word - clean.

The pressurization of the shoe press is slow and balanced, and even when high gram paper weights are produced, crushing does not occur. Because the full width of the sheet is evenly compressed, the rate of dewatering does not change much. In this way, loose cores do not appear on the paper core. Compared with roll press rolls, the paper quality of the shoe press has been significantly improved, and the bulkiness is higher and the carpet pattern is lighter.

Practice has proved that shoe press technology is the most advanced dewatering technology for paperboard, wrapping paper and document paper. It has great advantages in changing the longitudinal pressure and independently adjusting nip width and line pressure.

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