Working principle and technical core of vertical multi-stage semi submersible long shaft deep well turbine pump for ultra deep working conditions with ultra long underwater depth

A vertical multi-stage semi submersible long shaft deep well turbine pump with ultra deep working conditions and ultra long underwater depth. Its working principle is based on centrifugal force, and the long shaft is driven by a motor to rotate the impeller, achieving efficient vertical transportation of liquids; The core of the vertical multi-stage semi submersible long shaft deep well turbine pump technology lies in the collaborative optimization of segmented long shaft structure, multi-stage support system, corrosion-resistant materials, and intelligent sealing design to address the mechanical, sealing, and durability challenges brought by hundreds of meters of liquid depth.
1、 Working principle: Vertical fluid lifting driven by centrifugal force
The vertical multi-stage semi submersible long shaft deep well turbine pump adopts a vertical layout of "motor on top and pump body on bottom", and its working process is as follows:
·Preparation for start-up: The impeller of the pump is always immersed in the liquid, without the need for pumping or vacuuming, and can be started directly to avoid air resistance and cavitation problems.
·Energy conversion: The motor drives the impeller to rotate at high speed through the long shaft, and the liquid is thrown from the center of the impeller to the edge under the action of centrifugal force, forming a high-pressure zone; At the center of the impeller, a low-pressure zone is formed, and external liquid continues to flow in under the pressure difference.
·Multi stage boosting: For high head requirements (such as over 100 meters), a multi-stage impeller series structure is adopted, with each stage impeller gradually increasing the liquid pressure, ultimately achieving a head output of several hundred meters.
·Vertical transportation: After the liquid is pressurized step by step through the guide shell and lifting pipe, it is discharged from the horizontal outlet to complete the vertical extraction task from deep wells, storage tanks, or the seabed.
This process eliminates the need for traditional pump bottom valves and water intake devices, making it particularly suitable for closed containers, deep wells, and unmanned scenarios.
2、 Technical core: Four pillars supporting stable operation of ultra deep working conditions
1. Segmented long axis and multi-point support system
·The ultra long high-strength steel shaft (up to 10 meters/section) is connected by a sleeve coupling, which is easy to transport and install, and can adapt to underwater depths of 30-400 meters.
·Install a guide bearing (such as water lubricated graphite bearing or sliding bearing) every 3-5 meters to form multi-point support, effectively control radial runout (≤ 0.08mm/m), and suppress vibration and deflection.
·The LVG series ultra long vertical long shaft pump from Lijia Machinery adopts a "three-point support+mirror polished shaft body" design, ensuring smooth operation at a depth of 100 meters.
2. High performance materials and corrosion-resistant design
·Shaft body: Made of 316L stainless steel or titanium alloy, with a tensile strength of ≥ 550MPa and resistance to seawater corrosion (Cl ⁻ ≤ 50000ppm).
·Impeller: Made of duplex stainless steel 2205 or ceramic coating, suitable for strong corrosive environments with a sand content of 30% and pH 3-4, with a lifespan of over 15000 hours.
·Pump casing: lined with fluoroplastic and featuring a 316L outer shell structure, capable of withstanding extreme corrosion from pH 1-14, suitable for "hellish" media such as concentrated sulfuric acid and cyanide solution.
3. Multiple sealing and leak prevention mechanisms
·Double end mechanical seal: using silicon carbide (SiC) sealing ring+fluororubber group, leakage rate ≤ 0.001mL/h, equivalent to "butterfly drinking water level" sealing.
·Multi stage series sealing: High end models are equipped with 3-layer SiC sealing rings, with a pressure of ≥ 10MPa, and are matched with anti scaling lubricants (such as ethylene glycol) to prevent high-temperature scaling.
·No shaft seal design: Some pump models use auxiliary impeller power seals or labyrinth O-ring structures to completely eliminate leakage risks and are suitable for transporting flammable, explosive, or toxic media.