GDL Series Vertical Multistage Pipeline Pump
A vertical multistage inline pipeline pump for high-head duty: multiple impellers in an in-line casing reach 150 m at up to 1200 m³/h, installed straight into the pipe run.
The GDL series is a vertical multistage inline pipeline pump for high-head duty: multiple impellers inside an in-line casing lift the head above the single-stage ISG range, reaching 150 m while keeping the same in-pipe footprint.
It covers flow from 1.6 to 1200 m³/h with motor power from 0.18 to 132 kW and liquid temperatures from -20°C to 120°C.
The suction and discharge sit in the same straight line, and the rotor parts are built from a shaft, impellers, impeller retaining sleeves and shaft sleeves between bolted inlet, middle and outlet sections, so the pump installs like a valve and can be serviced without major pipework alterations.
It is used for boiler feed, pressure-vessel water supply, high-rise pressure boosting, fire fighting, reverse-osmosis feed and tall-building HVAC.
| Parameter | Specification |
| Type | Vertical multistage inline (pipeline) centrifugal pump |
| Flow | 1.6–1200 m³/h |
| Head | 5–150 m (GDL multistage range above 80 m) |
| Power | 0.18–132 kW |
| Temperature | -20°C to 120°C |
| Stages | Multiple impellers on a common shaft — stage count sets the head |
| Construction | Inlet, middle and outlet sections connected by fastening bolts |
| Rotor parts | Shaft, impellers, impeller retaining sleeves and shaft sleeves |
| Shaft seal | Mechanical seal, lubricated and cooled by balance-chamber pressure water |
| Ports | Suction and discharge in the same straight line (inline) |
| Installation | Fits into the pipeline at any position or direction, like a valve |
| Medium | Cold water, hot water and liquids similar to water in physical and chemical properties |
| Parameter | Specification |
| Flow rate | 1.6–1200 m³/h |
| Head | 5–150 m (GDL multistage range above 80 m) |
| Motor power | 0.18–132 kW |
| Number of stages | Multiple impellers on a common shaft; stage count sets the head |
| Liquid temperature | -20°C to 120°C |
| Casing construction | Inlet, middle and outlet sections bolted together |
| Rotor assembly | Shaft, impellers, impeller retaining sleeves and shaft sleeves |
| Shaft seal | Mechanical seal, lubricated and cooled by balance-chamber pressure water |
| Port arrangement | Suction and discharge on the same axis (inline) |
| Installation | Fits into the pipeline at any position or direction, like a valve |
| Duty range | Boiler feed water, pressure-vessel water supply, hot-water circulation, high-rise water supply and fire pressurisation |
The GDL series is published as a capacity and configuration range rather than a numbered model table. Choose the flow first, then set the number of stages to reach the total head, and confirm the duty point against the system head and available NPSH.
- Shaft seal: a mechanical seal fitted to the shaft and lubricated and cooled by the pressure water in the balance chamber — wear-resistant, leak-free and with a low failure rate.
- Casing sections: inlet, middle and outlet sections are fastened together with bolts, so the rotor assembly can be reached for service.
- Rotor parts: the rotor consists of the shaft, impellers, impeller retaining sleeves and shaft sleeves.
- Hydraulics: a hydraulic model designed for energy saving gives high conveying efficiency with smooth running, reduced energy consumption and lower flow noise.
- Installation: inlet and outlet lie in the same straight line, so the pump can be installed at any position or direction on the pipeline like a valve, which makes installation and maintenance convenient.
- Materials: materials are matched to the liquid — cold water, hot water or liquids similar to water in physical and chemical properties; confirm suitability for other media.
- Boiler feed water: supplies feed water to boilers, the duty the GDL range is especially suited to.
- Pressure vessels and hot-water circulation: feeds pressure vessels and circulates hot water in closed loops.
- High-rise building water supply: raises water pressure for upper floors and pressurised building services.
- Fire pressurisation: maintains pressure on fire-fighting and firewater systems.
- Reverse-osmosis feed: delivers feed water to RO and other treatment systems at the required pressure.
- Food, brewing and pharmaceutical: transfers liquids with properties similar to water in food, brewing and pharmaceutical plants.
- Irrigation and hydraulic washing: serves farmland irrigation and hydraulic washing duties where high head is needed.
- Confirm the required total head first, because the multistage design reaches 150 m and the stage count sets the pressure.
- Select motor power within the 0.18 to 132 kW range from the duty point, and check the operating point against the published curve.
- Keep the liquid temperature within -20°C to 120°C and confirm the liquid is water or similar in physical and chemical properties.
- Verify NPSH available at the inlet, which is critical for high-head multistage operation.
- Confirm the mechanical seal is suitable for the liquid and that the balance-chamber seal water supply is available where required.
- Allow headroom and access for lifting the rotor assembly, since the casing sections are bolted rather than split horizontally.
What head can the GDL multistage pipeline pump reach?
The GDL series reaches heads up to 150 m, above 80 m in the multistage range, with flow from 1.6 to 1200 m³/h.
Where is the GDL pump used?
For boiler feed water, pressure-vessel water supply, hot-water circulation, high-rise water supply, fire pressurisation, reverse-osmosis feed and food, brewing and pharmaceutical transfer.
What temperature range does the GDL cover?
It handles liquid temperatures from -20°C to 120°C, with motor power from 0.18 to 132 kW.
How is the GDL shaft sealed?
A mechanical seal seals the shaft, lubricated and cooled by the pressure water in the balance chamber, giving a wear-resistant, low-leakage and low-failure seal.
How is the GDL pump maintained?
The inlet, middle and outlet casing sections are bolted together, so unbolting them gives access to the rotor assembly for service without major pipework alterations.
Related Products
- ISG Series Vertical Inline Pipeline Pump
- Pipeline Circulation Pump
How to Choose a GDL Multistage Pipeline Pump
Quick answer: Multistage inline pumps are selected from flow and total head. The GDL gives high pressure with a small footprint, reaching 150 m at up to 1200 m³/h, and installs directly in the pipeline with bolted casing sections.
Why choose a multistage inline pump instead of a single-stage inline pump?
Use the multistage GDL when the total head is above the single-stage range — above roughly 80 m — such as boiler feed, high-rise boosting or RO feed. It adds stages on a common shaft to raise head while keeping the in-line, small-footprint installation of a pipeline pump.
How is the GDL pump sealed and serviced?
The shaft uses a mechanical seal lubricated and cooled by the pressure water in the balance chamber. The inlet, middle and outlet casing sections are bolted together, so the rotor assembly — shaft, impellers, impeller retaining sleeves and shaft sleeves — can be reached for maintenance. See the boiler feed pump selection guide for boiler duty.
What has to be confirmed before ordering?
The duty flow and total head, number of stages, liquid temperature, NPSH available, pipe size and flange arrangement, and the motor supply.
Selection Data to Send Our Engineers
- Flow rate (m³/h)
- Total head / pressure (m)
- Liquid name and temperature
- Number of stages required
- NPSH available
- Pipe size and flange arrangement
- Motor voltage, frequency and duty
Industry Applications
Explore how this equipment can be applied in related industrial sectors and review application-specific selection guidance.