DG Series Multistage Hot Water Pump

The DG series is a horizontal, single-suction, multistage sectional centrifugal pump for clear water at up to 105°C and for liquids with physical and chemical properties similar to water. Published coverage is 3.7-1350 m³/h at heads of 49-1800 m with motor ratings of 3-1120 kW, which suits municipal water supply and drainage, small boiler feed, garden irrigation and fire-fighting pressurised supply. The stator, rotor, bearings, shaft seal, transmission, inlet and outlet and coupling make up the pump, and head is built up stage by stage in the sectional casing. The shaft seal is a combination of mechanical seal or packing seal with high-quality hard alloy seal rings, which improves the wear resistance of the sealing parts. Running is smooth with low noise, and the compact body keeps the installation footprint small in boiler houses and plant rooms.

The supplier publishes one staged multistage table covering the D, MD, DG and DF families. The rows below are the DG-prefixed models from that table, showing how head increases with each added stage.

• Small boiler feed: Supplies feed water to small industrial and heating boilers.
• Municipal water supply and drainage: Moves water in town supply and drainage networks.
• Fire-fighting pressurised supply: Provides high-pressure water to fire protection systems.
• Garden and landscape irrigation: Irrigates parks, gardens and landscape areas.
• Hot water transfer: Circulates hot water in heating and process loops.
• High-rise building supply: Boosts water to elevated storage and tall buildings.

• Count the stages required for the head you need, because the DG series builds pressure stage by stage at a fixed flow per casing size.
• Keep the medium inside the published 105°C limit and confirm whether it is clear water or a corrosive liquid before choosing materials.
• Compare motor power with the duty shaft power and allow margin for start-up and for hot-water duty.
• Choose between a mechanical seal and packing, according to the acceptable leakage and the maintenance regime on site.
• Confirm the NPSH available at the suction, as hot water needs a positive inlet pressure to avoid cavitation.