Suction pipe extension by cantilever pumps can be used to get deeper suction. This makes use of deeper reservoirs possible while maintaining the benefits of cantilever pumps.
The cantilever pump is installed at the top of a sump/tank in the liquid, the so-called wet setup
With the fluid level above the impeller of the pump, the pump can be turned on and off at any time. The pump can pump the medium away until the minimum liquid- level for operation is reached. Longer pumping is technically unwise because the liquid coverage will become too small, which causes the pump to draw air whirls. This has an adverse effect on the life time of the impeller.
As soon as the liquid level is below the impeller at the suction extension and the pump is switched off the pump will no longer be primed, the liquid flows away and the impeller becomes dry. The pump can no longer be started in this area.
The liquid level for pump operation is also limited by cavitation. When the liquid level drops, the pressure at the impeller inlet and thus the NPSHa decreases. When the margin between NPSHa and NPSHr becomes too small, cavitation erosion will damage the impeller and operating the pump is not recommended. The pump can be started again when the impeller is primed. Suction extensions of 5 meters are possible in many cases, depending on the operating conditions.
By applying suction pipe extension, the advantages of cantilever pumps can also be used with deeper pump basements or liquid tanks.
Another solution for pumping liquids that should not come into contact with the shaft seal and bearings of the pump is through the following system layout.
Cantilever Pump for a high reservoir with an intermediate reservoir for switching the pump on and off.
The medium does not come into contact with shaft seal or bearings
For more advantages of cantilever push here