Multistage Pumps

Parameters of Multistage Pumps

Structure Description: D, DG, MD, DF & DY Multi-Stage Centrifugal Pumps

The D, DG, MD, DF, and DY series multi-stage pumps are constructed from four major assemblies: the fixed section, the rotor, the bearings, and the shaft seal.

1. Stator Section

The fixed casing is a segmented design, primarily comprising an inlet section, intermediate stages, and an outlet section, all tightly secured by through-bolts to form the pressurized working chamber. Pump orientation varies by model: The D Series typically features a horizontal inlet and vertical upward outlet, while the DG Series has vertically upward inlets and outlets. The MD, DF, and DY Series have a vertical upward outlet, with inlets generally horizontal but available in a vertical configuration.

2. Rotor Section

The rotating assembly consists of the shaft, impellers, a balance drum, and shaft sleeves. Power is transmitted via the shaft to the impellers. The balance drum is critical for hydraulically balancing the axial thrust generated by the impellers. Replaceable shaft sleeves are installed to protect the shaft from wear.

3. Bearing Assembly

This section includes the bearing housing, bearings, and covers. Most models employ rolling-element bearings lubricated with grease. Exceptions are the 85-67, 155-67, and 600-60 models, which use oil-lubricated sliding bearings, though the 85-67 and 155-67 can be configured with rolling bearings.

4. Shaft Seal

Shaft sealing is typically accomplished with gland packing. The system includes a seal chamber, packing, and a throttle bushing. A controlled flow of pressurized water is introduced into the seal chamber for sealing, cooling, and lubrication. The D Series uses internal pump pressure for this purpose, while the DG, MD, DF, and DY series can use either internal pressure or an external supply. Mechanical seals are a common alternative for these models.

5. Drive

The pump is directly driven by a prime mover through an elastic coupling. When viewed from the drive end, the standard rotation is clockwise.

D Series Multi-stage Pumps

The D Series comprises single-suction, multi-stage centrifugal pumps engineered for high-pressure applications. They are suitable for pumping clear water and similar fluids at temperatures ≤80°C.

These pumps are ideal for industrial and municipal water systems, pressure boosting in high-rise buildings, irrigation, fire protection, long-distance water transfer, and HVAC circulation, with a common application in small boiler feed systems.

Key Features

• High operational efficiency and a broad performance range.

• Smooth, quiet operation with extended service life.

• Ease of installation and maintenance.

• Customizable for diverse media (hot water, oils, corrosive liquids, mild abrasives) by altering wetted part materials, seal types, and adding cooling systems.

Technical Parameters

DG Series Multi-Stage Boiler Feed Pumps

The DG Series comprises horizontal, multi-stage, single-suction, radially-split centrifugal pumps engineered for high-pressure feedwater applications. They are designed to handle clear water or liquids with similar physical and chemical properties, at temperatures up to 250°C.

These pumps are widely deployed in critical industrial processes within power generation, metallurgy, and centralized heating systems for boiler feed duties, with maximum head capabilities reaching 1800 meters.

Key Features & Design:

• Advanced Hydraulic Design: Incorporates an optimized hydraulic model to ensure high operational efficiency, a broad performance range, smooth operation, and low noise levels.

• Robust Construction: The pump casing features an axial split design at the centerline, facilitating disassembly and maintenance without disturbing the rotor or pipeline connections. Standard configuration includes a vertically upward suction and discharge, with clockwise rotation (viewed from the drive end). Counter-clockwise rotation is available as a custom order.

• Reliable Shaft Sealing: Offers flexible sealing options, including both soft packing and mechanical seals, to suit various operational requirements. This design ensures safe, reliable sealing with straightforward and quick servicing.

Performance Summary:

The DG Series provides an extensive range of models to meet diverse operational demands. Performance parameters across the series cover:

• Material: The primary liquid-end components of the pumps are manufactured from cast iron. The exceptions are models DG85-80 and 200DG43, which utilize cast steel.

• Shaft Seal: Mechanical Seal or Gland Packing Seal

• Flow Rate: 3.75 to 900 m³/h

• Head: 19 to 1872 meters

• Efficiency: Up to 84%

• Motor Power: 4 to 2800 kW

• Fluid Properties: Clean water or similar liquids, free of solids, Up to 250°C.

This combination of robust construction, high efficiency, and operational reliability makes the DG Series multi-stage pump an ideal and trusted solution for demanding high-pressure boiler feed applications.

MD Series Mining Wear-Resistant Multi-Stage Pumps

The MD Series wear-resistant multi-stage centrifugal pump is engineered for demanding applications involving abrasive slurries and contaminated water, including neutral mine water with solid contents up to 1.5% (particle size < 0.5 mm). It is ideal for harsh industrial environments such as steel plants, mine dewatering, and wastewater transfer, handling media at temperatures up to 80°C.

Key Features & Advantages

• High Efficiency & Performance: Incorporates an optimized hydraulic model for superior energy efficiency across a wide operational range.

• Robust Durability: Constructed with wear-resistant materials to ensure extended service life and minimal efficiency loss when handling abrasive media.

• Operational Reliability: Features smooth and stable operation with low noise levels, ensuring high operational safety and reduced maintenance.

• Ease of Maintenance: Designed for straightforward installation, inspection, and servicing.

Performance Parameters

Sevice Life & Reliability

The pump's durability is validated under various operating conditions:

• Clear Water (<0.1% solids): Over 5000 hours of operation without major overhaul; efficiency degradation ≤ 6%.

• Moderate Slurry (0.1% - 1% solids): Over 3000 hours without major overhaul; efficiency degradation ≤ 5%.

• High-Concentration Slurry (1% - 1.5% solids): Over 2000 hours without major overhaul; efficiency degradation ≤ 6%.

Sealing Options

To suit diverse application needs, the MD Series offers two sealing configurations:

• Packed Gland Seal: Recommended for applications with non-stringent leakage requirements or media containing significant solid particles, offering robustness and ease of maintenance.
  

• Mechanical Seal: Suitable for high-temperature, high-pressure, or corrosive conditions where leak-free operation is critical. Both sealing systems effectively prevent medium leakage and ensure pump integrity.

DF Series Stainless Steel Corrosion-Resistant Multi-Stage Centrifugal Pump

The DF Series horizontal multi-stage centrifugal pump is engineered for handling clear corrosive liquids free of solid particles in the chemical, petrochemical, pharmaceutical, and metallurgical industries.

Designed with corrosion-resistant materials, it efficiently transfers aggressive media within a temperature range of -20℃ to 105℃, with maximum allowable inlet pressure of 0.6 MPa.

Design Features & Construction

• Corrosion-Resistant Materials: Wetted components utilize stainless steels (1Cr18Ni9, 1Cr18Ni12Mo2Ti, etc.) or other corrosion-resistant alloys, selected based on specific media properties

• Advanced Hydraulic Design: Incorporates energy-efficient hydraulic models ensuring high efficiency (32%-84%) across broad operational ranges

• Axial Force Balance: Employs balance drum mechanism for most models, with specific variants using opposed impeller arrangement

• Flexible Sealing Systems: Standard soft packing seals with optional mechanical seals for zero-leakage applications

• Robust Bearing System: Primarily utilizes grease-lubricated rolling element bearings, with specific models featuring oil-lubricated sleeve or roller bearings

• Standardized Configuration: Features vertical upward discharge orientation and clockwise rotation (viewed from drive end).

Technical Parameters

Applications

Ideal for handling corrosive liquids in:

• Chemical processing and petroleum refining

• Metallurgical operations and mining drainage

• Paper manufacturing and industrial wastewater systems

• Agricultural chemical transfer

Standard Supply

Complete unit includes pump, coupling, motor and base. Optional accessories: discharge cones, gate valves, check valves, and essential spare parts (impellers, wear rings, guide bushings, balance drums, and shaft sleeves).

The DF Series combines superior corrosion resistance with robust engineering, ensuring long service life and minimal maintenance in demanding industrial environments.

DY Series Multi-Stage Oil Pump

The DY series is a specialized multi-stage centrifugal pump derived from the D-type pump, engineered for transporting petroleum products and other compatible liquids in the petrochemical industry. It is designed to handle clean media free of solid particles, with a viscosity of less than 120 cSt.

Design Features & Capabilities

• Media & Temperature Range: Suitable for a wide range of media, including oil, petroleum products, hot water, corrosive liquids, and fluids containing abrasives. The standard operating temperature range is -20°C to 150°C.

• Inlet Pressure: Allows a maximum inlet pressure of 0.6 MPa.

• Material & Configuration: Pumps are categorized into DYⅠ (cast iron), DYⅡ (cast steel), and DYⅢ (stainless steel) series based on the material of their wetted parts. Configurations support both horizontal and vertical inlet/outlet orientations.

• Efficiency & Performance: Incorporates an optimized hydraulic model for high efficiency, energy savings, broad operational range (Flow: 3.7 - 1350 m³/h; Head: 48 - 1800 m), smooth operation, low noise, and long service life.

• Sealing & Cooling: Offers flexible sealing with either mechanical seals or packed glands, complemented by an effective cooling system.

• Bearings & Lubrication: Utilizes either sliding bearings (with forced circulation or oil-ring splash lubrication) or rolling bearings (grease lubrication), depending on the model.

Structural Details

• Orientation: Most models feature a vertical inlet and vertical outlet design.

• Support: Pumps generally employ foot support, with the exception of the DYⅡ155-67 model which uses centerline support.

• Rotation: Clockwise rotation when viewed from the motor end.

Standard Supply

The pump is supplied as a complete unit, typically including the pump itself, a certified explosion-proof motor, a common base (or dedicated base), a check valve, and essential spare parts.

Key Performance Parameters