Check out these to know how braided packing works

Packing (braided packing) is also called sealing packing, which is usually woven from softer threads. Usually, the cross-sectional area is square or rectangular or circular strips are filled in the sealing cavity to achieve sealing.

The packing seal has long been plugged with fibers such as cotton and linen in the leakage channel to prevent the liquid flow from leaking, and it is mainly used as the shaft seal of the water lifting machine. Due to the wide source of fillers, easy processing, low price, reliable sealing and simple operation, it is still used today.

The working principle of packing The surface of the shaft is very uneven under microscopic conditions, and it can only partially fit with the packing. So there is a tiny gap between the packing and the shaft, like a labyrinth. The medium is intercepted many times in the labyrinth, so as to achieve the sealing effect.

The packing seal is installed in the stuffing box by the packing, and the packing is pressed against the surface of the shaft through the packing gland. Since the surface of the shaft is always rough, it can only partially fit with the filler, and part is not in contact, which forms countless labyrinths.

When the pressurized medium passes through the shaft surface, the medium is throttled many times, and the sealing is achieved by virtue of this "labyrinth effect". The fit and friction between the packing and the shaft surface are also similar to the sliding bearing, and there should be enough liquid for lubrication to ensure the seal has a certain life, the so-called "bearing effect". It can be seen that a good packing seal is a combination of labyrinth effect and bearing effect.

The compression force of the packing against the shaft is produced by tightening the gland bolts. Since the packing is an elasto-plastic body, after being axially compressed, a frictional force is generated, which causes the pressing force to gradually decrease along the axial direction, and at the same time, the radial pressing force generated makes the packing close to the shaft surface and prevents the medium from leaking out.

The distribution of radial compression force decreases sharply from the outer end (gland) to the inner end, and then gradually decreases. The distribution of medium pressure gradually decreases from the inner end to the outer end. When the medium pressure at the outer end is zero, the leakage is very high Less, more than zero leakage.

With the continuous emergence of new materials, the packing structure has also changed a lot, which will undoubtedly promote the application of packing seals more widely. The materials used as packing should have the following characteristics: a certain elasticity and plasticity.

When the packing is axially compressed, it can generate a large radial compression force to obtain a seal; when the machine and the shaft vibrate or the shaft has beating and eccentricity, it can have a certain compensation ability (following); chemical stability sex. It is neither corroded, swollen nor polluted by the medium; impermeability.

The medium has some penetration into most fibers, so the packing structure is required to be dense. For this reason, it is often necessary to impregnate and fill various lubricants and fillers when making the packing; good self-lubrication, small friction coefficient and wear resistance; temperature resistance . It can withstand a certain temperature after friction and heating; it is easy to disassemble; it is simple to manufacture and cheap.

Hebei Fuyuan Sealing Material Co., Ltd. can provide various types of braided packing including asbestos packing, PTFE packing, graphite packing, carbon fiber packing, ceramic fiber packing, kevlar (aramid) packing, if you are interested, welcome to consult!