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Having 26 series -312 varieties - over 1000 pump models
Focused on water pump research and development manufacturing for 36 years
Free training for operation and maintenance personnel/free installation guidance/free provision of installation drawings
Gland packing (packing)
This packing seal (gland packing) is suitable for various models and types of pumps, such as multistage centrifugal pumps, single-stage centrifugal pumps, and mid-open centrifugal pumps. Available options include graphite packing, asbestos packing, and high-water-based packing. The reference prices range from 1 to 50 yuan per meter.
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Overview of Packing Seals
Packing seals, also known as packing or "gland packings," are typically made by braiding relatively soft fibrous materials. These materials, in the form of square-cross-section strips, are packed into the sealing cavity to achieve a tight seal. Historically, packing seals first emerged when fibers such as cotton and hemp were stuffed into leak paths to prevent fluid leakage—primarily used as shaft seals for water-lifting machinery. Due to their wide availability, ease of processing, low cost, reliable sealing performance, and simple operation, packing seals have remained in use to this day. Today, gland packings are extensively employed for sealing rotating shafts in centrifugal pumps, compressors, vacuum pumps, mixers, and ship propellers; as well as reciprocating shaft seals in piston pumps, reciprocating compressors, and refrigeration units, and for rotary sealing applications involving valve stems in various types of valves.
Types of Packing Seals
The types of packing seals (gland packings) include aramid packing, graphite packing, PTFE packing, high-water-based packing, carbon fiber packing, aramid-carbon fiber packing, aramid-PTFE packing, ramie packing, tallow packing, asbestos packing, ceramic packing, oil-impregnated packing, and rubber packing, among others.
Asbestos packing is braided from asbestos yarn impregnated with heat-resistant lubricating oil and graphite, making it suitable as a sealing material for rotating shafts, reciprocating pistons, or valve stems. The media it seals against include steam, air, industrial water, and heavy petroleum products. Depending on operational requirements, we can also manufacture asbestos packing containing steel wire (or nickel wire, stainless steel wire) and coated with lead powder and oil.
Graphite packing is a flexible, high-strength braided packing material made from graphite yarn reinforced with stainless steel wire. When used in combination with other packing materials, it delivers outstanding sealing performance, making it an exceptionally effective sealing material—particularly under high-pressure conditions. With the exception of a few strong oxidizing agents, it can be used to seal hot water, high-temperature and high-pressure steam, heat-transfer fluids, hydrogen gas, ammonia, organic solvents, hydrocarbons, cryogenic liquids, and other media. It is also a uniquely versatile sealing packing material, ideally suited for applications involving media containing solid particles that are prone to abrasion. It is especially recommended for use with superheated steam, solvents, liquefied gases, syrups, and other easily abrasive fluids.
Aramid fiber braided packing boasts excellent lubricity and wear resistance. Its most outstanding features are high strength, high abrasion resistance, as well as good chemical resistance, high resilience, low cold flow, and ease of quick disassembly and assembly. It is particularly suitable for dynamic sealing applications involving media containing solid particles.
The PTFE packing is made from pure PTFE fibers woven without any PTFE emulsion or lubricating oils. Because it is solid-woven, it exhibits excellent flexibility and adjustability, ensuring a perfect fit with the shaft and stuffing box. It boasts outstanding corrosion resistance, superior self-lubrication, and excellent anti-sticking properties. This packing is suitable for applications in industries such as chemical processing, food, pharmaceuticals, papermaking, synthetic fibers, and fine chemicals—places where contamination must be strictly avoided. It is applicable to all chemical media except those containing soluble alkali metals and free fluoride ions.
The principle of packing seals
The working principle of packing seals (gland packings) is that the shaft surface, under microscopic examination, is highly irregular and can only partially conform to the packing. Consequently, there exists a tiny gap between the packing and the shaft—a gap that resembles a labyrinth. As the medium flows through this labyrinth, it undergoes repeated throttling, thereby achieving a sealing effect.
Packing Seal Technical Requirements
① When cutting packing (gland packing), it’s best to wrap the packing around a round steel rod with a diameter identical to that of the valve stem to ensure accurate dimensions and parallel cut edges. The cut edges should be neat and free of loose asbestos fibers. Ideally, the cut edges should be at a 45° angle.
② Each packing ring should be individually pressed into the packing box. When installing valve packing, a small amount of flaky dry graphite powder or lubricating oil should be placed between each ring.
③ To facilitate installation, when pressing in the asbestos packing wrapped with aluminum foil, apply a thin layer of flake graphite powder mixed with machine oil to the inner edge of the packing.
④ The width of the packing seal (gland packing) selected should match the dimensions of the packing box or be 1 to 2 millimeters larger.
⑤ When installing oil-immersed asbestos packing, it is best to install dry asbestos packing for the first and last rings to prevent oil leakage.
⑥ When installing packing seals (gland packings), the joints of the packing rings must be staggered; typically, the joints are offset by 120° or 180°. The packing should not be compressed too tightly—adjust it appropriately according to the operating pressure.
⑦ The depth to which the compression packing is pressed into the packing box is generally equal to the height of one turn of packing, but it must not be less than 5, and there should be sufficient clearance left for further tightening.
⑧ When installing the packing gland, ensure that the clearance between the packing gland and the valve stem remains consistent to prevent uneven compression, which could lead to uneven stress on the packing and rapid wear. Generally, this clearance should be kept no greater than 0.1 to 0.15.
⑨ The key points to ensure the quality of packing installation are: choosing the right type; conducting thorough inspections (checking the valve stem, packing box, packing material, etc.); ensuring accurate dimensions; and applying proper compression (the first compression circle is crucial—make sure that each subsequent circle of packing deforms uniformly and maintains consistent thickness).
Why choose us?
Changsha Zhonghlian Pump Industry Co., Ltd. was founded in 1989 and was independently established after the restructuring of Changsha Water Pump Factory. It is a comprehensive national high-tech enterprise integrating design, research and development, manufacturing, and service. The company was listed on the Hunan Provincial Equity Exchange on December 31, 2019, with the abbreviation "Zhonghlian Pump Industry" and the equity code: 600275HN. It is currently a key backbone enterprise in China's centrifugal pump industry and one of the major professional manufacturers of multi-stage pumps in the country. The headquarters is located in Changsha City, Hunan Province, a historical and cultural city in China.
Square meters of land area
100% factory pass rate
Square meters of land area
100% factory pass rate
Q
What is your typical delivery time?
A
Models in stock can be shipped the next day at the latest. All others are custom-made, with lead times generally ranging from 7 to 90 days depending on the product size and project specifics. Please contact our sales manager for details: 0731-88632200 。
Q
Do you have centrifugal pumps in stock?
A
Centrifugal pumps come in numerous models and configurations. Except for a small number of high-volume, standard models that are in stock, the vast majority are not stocked and are customized products. We need to select a pump based on your site's flow rate, head, media temperature, pH value, and installation conditions, etc., to determine the pump model and configuration before we can submit an order to the factory for production.
Q
What information should I provide when requesting a quote?
A
Generally, to obtain an accurate quotation, we recommend providing us with the following information: pump flow rate, head, on-site operating voltage and frequency, temperature, pH value, and solid particle content of the fluid being conveyed, and on-site installation conditions (horizontal or vertical installation), etc.
If you are not sure, don't worry, our business managers will assist you in determining this.
Q
What products do you mainly produce?
A
Zhonglian Pump Industry manufactures various large industrial centrifugal pumps. Main products include: self-balancing multi-stage pumps, multi-stage centrifugal pumps, single-stage centrifugal pumps, split-case pumps, chemical pumps, submersible pumps, pipeline pumps, long-shaft pumps, condensate pumps, etc.
Q
Why is it so slow to get a price quote?
A
Because centrifugal pumps are non-standard customized products with many models, the price range is also very large. Even for the same model, the price difference is also very large due to different materials and configurations. Taking the most common water pump accessory—the impeller—as an example, the price of a stainless steel impeller is several times that of a cast iron impeller. Therefore, we need to clarify the relevant information to give you an accurate price. Normally, if you provide relatively comprehensive information, we can quote within 5 minutes.
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Hotline:
+86 0731-88632200
Export Trade/Technical Support:
+86 153-4831-2290
Head Office Email:
zoomlian@yeah.net
No. 210, Huanbao Zhong Road, Yuhua District, Changsha City, Hunan Province, Leowoju Wisdom Valley Building B, 8th Floor
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