Vertical Shaft Sewage Pumps

What is a vertical shaft sewage pump?

In vertical shaft sewage pumps, the electric motor sits above the wastewater pit or tank on the dry side, while the pump casing descends into the pit via a long shaft. Because the motor never contacts the liquid, waterproof motor insulation is not required and motor maintenance can be carried out easily from the surface. These pumps are used in industrial facility wastewater pits, treatment plants, and large building sumps.

Model types

• Standard vertical shaft sewage pumps: Pump solids-laden wastewater with a wide-passage impeller.
• Macerator-blade models: Shred fibrous waste to reduce the risk of clogging.

Models in this category are available in 380 V three-phase. The shaft length must be selected to match the depth of the pit.

Difference from a submersible sewage pump

In submersible sewage pumps the motor is submerged in the liquid and the entire pump is lowered into the pit. With vertical shaft pumps the motor remains outside, so the whole pump does not need to be removed in the event of a motor fault. However, because of the length of the shaft and bearings, installation must be carried out carefully and the pump must be mounted on a sturdy support frame. Adequate space for the motor must be available above the pit.

Installation and maintenance

The pump is secured to a sturdy plate or support frame placed over the pit; the shaft must be vertical and vibration-free. Sufficient clearance must be left between the pump inlet and the pit floor to prevent sediment from being drawn in. Automatic operation can be achieved with level float switches. Bearing lubrication and shaft seal inspection are part of routine maintenance.

Frequently asked questions

Can these pumps run continuously?

They are designed for heavy-duty use; even so, motor protection must be provided with a suitable control panel.

How is the shaft length determined?

It is determined by taking into account the depth of the pit and the level at which the pump will be suspended.

When is a macerator model required?

If the wastewater contains rags, wipes, or fibrous materials, a macerator model reduces the risk of clogging.

Is a single-phase model available?

Models in this category are three-phase; for single-phase requirements, see submersible sewage pumps.

How is level control achieved?

The pump can be operated automatically with level float switches and a suitable control panel.

Why is maintenance easier on these pumps?

Because the motor remains above the pit, motor connections, bearings, and the cooling fan can be inspected in a dry environment. The submerged part of the pump is only removed when necessary.