Deep well submersible multistage pump, self-balancing multistage pump (stable axial force for high-stage high-pressure working conditions).
1. Suction Section, Discharge Section & Middle Stage Casing
Segmented housings locked by tie rods to bear high internal pressure; inlet & outlet arranged on same side or bottom for easy pipeline connection.
2. Multi-Stage Impellers (Core Pressure-Boost Components)
Closed single-suction impeller, each stage completes one centrifugal pressure rise; more stages mean higher total head (common stages: 2–16).
3. Diffuser Vanes
Installed between two adjacent impellers, guide fluid smoothly into next stage and convert kinetic energy into static pressure to improve pump efficiency.
4. Main Shaft & Sleeve
High-strength alloy steel through shaft carrying all impellers; shaft sleeve protects main shaft from medium erosion & abrasion.
5. Axial Force Balancing Device (Unique for Multistage Pumps)
Balance disc / balance drum structure to counteract huge axial thrust generated by multi-stage impellers, preventing bearing wear and shaft axial movement.
6. Bearing Assembly
Radial support bearings + thrust bearings, grease/oil lubrication for long-term continuous high-speed operation.
7. Shaft Seal System
Cartridge mechanical seal with tungsten carbide & fluorine rubber for zero leakage; cooling flushing pipeline equipped for high-temperature media.
8. Driving Motor
Standard Y 3-phase motor, YB flameproof explosion-proof motor, connected via flexible coupling; variable frequency drive optional for constant pressure water supply.
Motor drives main shaft and all impellers to rotate synchronously at high speed:
1. Liquid flows into the **1st stage impeller** from suction section, accelerated and initially pressurized by centrifugal force.
2. High-pressure fluid enters diffuser for flow rectification & deceleration; kinetic energy converts to static pressure, then smoothly feeds into the next impeller.
3. The medium repeats the cycle of "impeller pressurization + diffuser pressure stabilization", pressure accumulates stage by stage.
4. After all stages finish pressurization, high-pressure liquid discharges uniformly from the outlet section.
Simplified explanation: Equivalent to multiple single-stage centrifugal pumps integrated in series. One single multistage pump can reach ultra-high head without connecting multiple pumps in pipeline.
1. Ultra-high head & high discharge pressure
Max head of single-stage pump is limited to ~120m; multistage pump easily achieves 200–1000m head for high-rise buildings, deep wells and long-distance delivery.
2. Flexible adjustable head
Total pressure can be modified by adding or removing impeller stages, one pump body fits multiple working conditions with strong versatility.
3. Small footprint for vertical type
CDLF/GDL inline vertical structure with coaxial inlet & outlet, directly installed into pipeline without separate pump foundation.
4. Stable outlet pressure & low flow pulsation
Progressive pressure stabilization eliminates pressure fluctuation; VFD matching realizes constant pressure water supply.
5. Diverse material options
Cast iron, SS304/SS316, wear-resistant alloy, duplex steel, covering clean water, hot water, corrosive chemical liquid and mine water with trace fine sand.
6. Energy-saving for high-pressure low-flow conditions
Under equal high-pressure requirements, single multistage pump brings lower pipeline loss & power consumption than multiple series single-stage pumps.
1. Not suitable for media with large solid particles or long fibers; no anti-clog wide channel, impurities will abrade impellers and block diffusers rapidly.
2. Numerous internal components, disassembly & maintenance procedures more complex than single-stage pumps.
3. Higher initial procurement cost compared with ordinary single-stage centrifugal pumps under same flow rate.
4. Lower hydraulic efficiency for low-head large-flow working conditions.
- Flow rate: 2～800 m³/h
- Total single-unit head: 20～1000 m (adjustable by stage quantity)
- Medium temperature: CDLF normal type -15~80℃; DG boiler type ≤105℃; customized high-temp version ≤180℃
- Allowable solid particles: Almost no hard solids; MD mining version permits trace fine sand (particle size ＜0.1mm)
- Applicable pH range: Cast iron 6–9; SS304 3–10; SS316 / duplex steel 1–12
- Max working pressure: 16MPa
- Matched motor power: 1.5～630kW
1. Construction & Fire Water Supply
Secondary pressure boosting for high-rise residential & office buildings, fire stabilization pump set, high-pressure sprinkler supply.
2. Thermal Power & Boiler Room
DG boiler feed pump, thermal circulation hot water delivery, condensed water recovery.
3. Mining Industry
D/MD underground mine dewatering, deep well water lifting, high-pressure process makeup water for mineral processing.
4. Environmental Water Treatment
High-pressure feed for RO reverse osmosis, pure water equipment, long-distance water transfer for water plant, circulating water boosting.
5. Chemical & Petroleum
DF anti-corrosion multistage pump for weak acid, salt solution and oilfield formation water injection.
6. Municipal & Agriculture
Mountain long-distance irrigation, water plant booster pump station, pipeline pressure increase.
1. Select multistage pump when required head ＞120m; choose single-stage pump economically for head ≤100m & large flow demand.
2. Clean water & building water supply: SS304 CDLF; boiler hot water: DG series; mine water with trace sand: MD; weak acid corrosion liquid: DF.
3. Reserve 10%~15% margin for flow & head to offset pipeline friction loss.
4. Must equip YB flameproof motor for flammable & explosive chemical environments; install motor rain cover for outdoor water supply.
5. Strictly forbidden for media containing fibers, plastic bags and coarse sand; replace with non-clog pump or slurry pump instead.
6. Match VFD control cabinet for 24h continuous constant pressure supply to stabilize pressure and cut power consumption.
1. Fully prime liquid before startup; dry running is strictly prohibited, which will burn mechanical seal and scratch impellers instantly.
2. Refill bearing grease every 500 running hours; shorten cycle to 300 hours for high-temperature boiler pumps.
3. Inspect balance device & balance disc clearance regularly; stop machine immediately for adjustment if excessive axial movement occurs.
4. Check inlet/outlet pressure, motor current, vibration & noise every shift; disassemble to clean scaled & worn impellers if severe pressure fluctuation appears.
5. Fully drain medium inside pump for long-term shutdown, flush all stage flow channels with clean water, coat anti-rust grease on shaft seal & impellers; drain residual water in winter to prevent casing crack.
