Changsha Zoomlian Pump Co., Ltd. 长沙中联泵业股份有限公司

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    Unveiling the Working Principle of Horizontal Multistage Pumps

    Publication Date:

    2025-10-01

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    The brine extraction process in the salt chemical industry places stringent demands on pump types, requiring exceptional corrosion resistance, stable head performance, and reliable continuous operation. Brine media contain highly concentrated chloride ions, which easily lead to equipment corrosion. Moreover, brine extraction often involves mining operations at depths of hundreds of meters, putting clear requirements on the pump's boosting capability and flow stability. Thanks to its core advantages—such as strong corrosion-resistant compatibility, a low-wear design without balance discs, consistently high head output, energy efficiency during operation, and convenient maintenance—the self-balancing multistage pump has become the mainstream choice for brine extraction in the salt chemical industry. Its flow components are predominantly made from corrosion-resistant materials like duplex stainless steel and Hastelloy alloys, enabling long-term resistance to brine media erosion and effectively addressing the common issue of leakage caused by corrosion in conventional pump designs. Additionally, by eliminating the traditional Multi-stage pump The balanced disc structure has been replaced with a self-balancing mechanism to counteract axial forces, significantly reducing component wear and extending the average trouble-free operating life to over 8,000 hours, perfectly suited for the continuous brine production requirements. Meanwhile, the multi-stage impeller series design ensures stable high-head output—each single stage can achieve a head of 50–80 meters, while multiple stages combined can meet the brine extraction depth needs ranging from 300 to 1,500 meters. Additionally, this design delivers operational efficiency that is 5%–8% higher than conventional multistage centrifugal pumps, leading to lower energy consumption costs over the long term. In this article, we introduce a manufacturer specializing in multi-stage pumps. Changsha Zoomlion Pump Industry This article will highlight the key design considerations for inlet and outlet pipelines when using self-balancing multistage pumps as brine extraction pumps, as well as practical daily maintenance methods, providing valuable insights to help salt chemical enterprises optimize the operation of their brine extraction equipment. ​


      Self-balanced multistage pump

     

    1. Import and Export Pipeline and Sealing Design

     

    To address the special requirements of high-solids-containing media, the self-balanced multistage pump has also been optimized in terms of its inlet and outlet piping as well as seal design:

    1. Install a conical filter on the inlet pipe: The mesh aperture is 5-10mm , intercepting large-particle impurities to prevent them from entering the pump and causing the impeller to jam.

    2. Install a check valve on the discharge pipe: This prevents medium backflow from scouring the impeller during shutdown, avoiding salt slurry backflow that could cause the impeller to reverse and accelerate wear.

    3. Sealed Design: Employs an external metal bellows mechanical seal, with the bellows material made of Hastelloy alloy or duplex steel. The sealing surfaces are crafted from silicon carbide. SiC ) Graphite (impregnated with resin) is wear-resistant and exhibits a low coefficient of friction. Meanwhile, the use of APIPlan11 (Self-flushing) +Plan52 (Pressure buffer tank) continuously flush the sealing chamber with clean desalinated water or filtered process media to prevent crystallization and blockages.

     

    II. Operational Control and Maintenance Measures

     

    Even with optimized design, damage still needs to be minimized through operational control and regular maintenance.

         1. Avoid operating at low flow rates with high head: It is recommended to keep the operating flow rate within the design flow range. 70%-110% To reduce backflow and vortices when operating away from the design conditions, thereby minimizing particle erosion on the impeller and pump casing.

    2. Control the medium temperature: Ensure the medium temperature does not exceed the crystallization point; for example, the sodium chloride solution temperature should be maintained at ≤ 60 ℃, to prevent crystalline particles from clogging the flow channels under high temperatures.

    3. Maintain a stable inlet liquid level: An excessively low inlet level can lead to cavitation, accelerating impeller wear. It is recommended that the inlet tank level be ≥ 1.5m。

    4. Daily Inspection: Monitor pump vibration (≤ 4.5mm/s )、Bearing temperature (≤ 70 ℃）and sealing leakage rate (≤ 5 Drop / Minutes), promptly stop and inspect the machine when abnormalities occur.

    5. Regular disassembly and inspection: Every time it operates 1000–1500 Conduct a disassembly inspection every hour, focusing particularly on the edges of the impeller blades and the outlet of the pump casing flow passages—ensure wear does not exceed 1mm It needs to be repaired or replaced; tungsten carbide overlay welding can be used to restore the impeller.

    6. Impeller Balance Correction: The impeller, after being replaced or repaired, must undergo an dynamic balance test. G6.3 Above the specified level), preventing vibrations and excessive wear caused by imbalance.

    7. Clean the flow passages: When shutting down, flush the pump’s internal flow passages with high-pressure water or process solvents to remove residual salt crystals and particle buildup, preventing the pump from seizing during the next startup.

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