Packing, also known as the static sealing packing, is usually braided from relatively soft fiber yarn. Usually, square、rectangular or rounded sectional area is filled into the sealed cavity.
Braided packing is made of expanded graphite yarn and is often used in most occasions except for strong oxidants. It can be used in boiling water, high temperature, high pressure steam, heat transfer medium, oil, acid, alkali, hydrogen, ammonia, organic solvents, etc. Hydrocarbons, cryogenic liquids and other media. It is a unique new type of sealing packing.
Working principle of packing The surface of the shaft is very uneven in microscopic conditions and can only fit partially with the packing. So there is a slight gap between the packing and the shaft, just like a maze. The medium is blocked several times in the labyrinth to achieve sealing.
The packing seal is packed in the stuffing box by the packing, and the packing presses the packing on the shaft surface. Because the shaft surface is always rough, it can only partially fit with the filler, and some parts are not in contact, thus forming numerous mazes. When the pressure medium passes through the shaft surface, the medium is throttled several times, and the seal is achieved by virtue of this “maze effect”. The fitting and friction between the packing and the shaft surface are also similar to those of the sliding bearing. The solid should have enough liquid to be lubricated to ensure that the seal has a certain lifespan, the so-called “bearing effect”. This shows that a good packing seal, that is, a combination of the labyrinth effect and the bearing effect.
With the continuous appearance of new materials, the structure of fillers has also changed greatly. This will undoubtedly promote the application of filler seals more widely. The materials used as fillers should have the following characteristics: They have certain elasticity and plasticity. When the packing is axially compressed, it can generate a large radial pressing force to obtain the seal; when the machine and shaft have vibration or the shaft has runout and eccentricity, it can have certain compensation ability (following property); chemical stability Sex. It is not corroded by medium, swelling, or contaminating medium; impermeability. The medium has some permeation to most of the fibers, so dense packing materials are required. For this reason, fillers are often required to be impregnated and filled with various lubricants and fillers; the self-lubricating properties are good, the friction coefficient is small, and the wear resistance is high; . When the friction and heat can withstand a certain temperature; easy removal; simple manufacturing, low prices.
Packing, sealing packing, is usually braided from relatively soft fiber yarn. It is sealed by filling a sealed cavity with a square cross-sectional area.
3.1芳香包装series of CiXi FEITE Sealing Material Co., Ltd.
Gold Aramid Fiber Packing, Huang aramid fiber packing, aramid fiber intertwined with white PTFE Packing, aramid fiber intertwined with black PTFE Packing This series of packing is made of aramid fiber as the main material, repeatedly impregnated with lubricant, PTFE emulsion Such as precision compilation. It has good high rebound, chemical resistance, low cold flow and high line speed. Compared with other types of packing, it can resist grain crystallizing medium and higher temperature. It can be used alone or in combination with other packings. Mainly used for medium particles, easy to wear conditions.
3.2PTFE Packingseries of CiXi FEITE Sealing Material Co., Ltd.
白色的PTFE包装，黑色PTFE包装，白色PTFE芳香纤维包装，黑色PTFE芳香包装，PTFE包装，白色PTFE浸渍包装，白色四氟化物浸渍的心脏包装这一系列包装由PTFE制成。具有出色的化学稳定性，耐腐蚀性，可密封性，高润滑性非粘性和良好的抗衰老耐力。它可以在 +250°C至-180°C的长时间内工作。除了熔融金属钠和液态氟，它可以抵抗所有其他化学物质并在Aqua Regia中沸腾。它主要用于不允许污染的条件，例如卫生条件，强烈的腐蚀性，高线速度和易穿磨损。
3.3Graphite Packingseries of CiXi FEITE Sealing Material Co., Ltd.
柔性石墨填料,金属增强Graphite Packing, carbon fiber-reinforced Graphite Packing, carbon fiber metal-reinforced Graphite Packing This series of packing characteristics is based on graphite as the main material. Has good self-lubrication and thermal conductivity, low friction coefficient, versatility, good flexibility, high strength, protection of the shaft and other advantages. According to different requirements, the use of carbon fiber, copper wire, 304, 316L, Yancai nickel alloy wire and other materials to strengthen. Mainly used under high temperature and high pressure conditions.
3.4Carbon fiber packingseries of CiXi FEITE Sealing Material Co., Ltd.
Super-elastic silicone core is coated with high-quality synthetic fibers and woven with PTFE emulsion, lubricant and barrier agent. It can effectively absorb mechanical vibrations and control leaks caused by vibrations. Has excellent resilience, self-lubrication, flexibility, wear resistance, high tensile strength, good chemical resistance and so on.
3.6 High temperature and high pressure packing of CiXi FEITE Sealing Material Co., Ltd.
In addition to the above materials, there are acrylic packing, high water-based packing, and ramie packing to meet various operating conditions.
4. Technical requirements
4.1 When cutting the packing, it is best to cut the packing around a round bar with the same diameter as the stem to ensure that the size is correct and the cuts are parallel. The incision should be neat and free of loose asbestos threads. The incision is preferably 45°.
4.2 Each packing ring should be pressed into the packing box separately. When pressing the valve packing, a small amount of scaly dry graphite powder or lubricating oil should be placed between each ring.
4.3 For ease of installation, press-fit aluminum foil wrapped with asbestos packing should be coated with a thin layer of scaly graphite powder blended with oil on the inner edge of the packing.
4.4 The width of the packing should be the same as the size of the packing box, or 1 to 2 mm.
4.6 When pressing the packing, the interface of the packing ring must be staggered. Generally, the interface is staggered by 120° or 180°; the packing should not be pressed too tightly and it must be properly adjusted according to the operating pressure.
4.7 The depth of the gland pressing into the packing box is generally a circle of packing height, but not less than 5, and should leave room for further tightening.
4.9 The key points for guaranteeing the installation quality of packing are: selection is correct; inspection is fine (check the stem, packing box, packing, etc.); accurate size; good pressure (pressing the first lap is the key to ensure that after pressing The packing of each circle is the same as the thickness and thickness.)
How to choose the right packing? There are two things that must be taken into account when choosing a packing.
5.1 Working conditions and packing performance should be consistent. According to the relevant technical data to select the best meet the requirements of the packing.
5.2 The packing size must be correctly selected according to the sealing requirements. To determine the cross section, use the following formula:
A damaged device may require a slightly larger cross-sectional packing to compensate for the damage.
—– CiXi FEITE Sealing Material Co., Ltd.