In this module, we’ll discover the features and benefits of the Grundfos end suction pumps. Let’s get started.

Over the life cycle of a pump, the largest proportion of total cost is energy consumption, which accounts for around 85 percent. That’s why improving efficiency has a significant impact on operational budgets as well as carbon emissions. So how does Grundfos achieve industry-leading efficiencies in the NB, NBS, NK end suction range?

A major contributor is the impeller design. Grundfos end suction pumps use Stainless Steel 304 investment-cast impellers with ultra-smooth surfaces, which reduce hydraulic friction and improve hydraulic performance and energy efficiency. Hydraulic balancing holes in the impeller reduce axial thrust, lowering bearing loads, quietening operation, and extending service life.

Together, these features reduce energy consumption and extend service intervals, which are valuable benefits in every pumping application. The pump volute also plays a key role.

Grundfos end suction pumps were designed using advanced Computational Fluid Dynamics (CFD) analysis to optimise hydraulic efficiency. Other design elements also contribute to high efficiency, including:

Integrally cast diffuser vanes

Top-centreline discharge

Integrally cast volute foot

Let’s take a closer look at how these features improve performance and reliability.

Integrally cast diffuser vanes balance flow to the eye of the impeller, promoting smoother operation.

The top-centreline discharge allows for a self-venting design, more compact piping layouts, and improved weight distribution.

And to support long-term reliability, the volute foot provides a stable, distortion-free mounting base that protects the rotating assembly and enables a true back pull-out design for easier servicing. As well as efficiency, reliability is also crucial.

Mechanical seal failures are the most common cause of system downtime, with issues ranging from shaft misalignment and axial movement to abrasive fluids and dirt on the seal face. How does Grundfos address this?

The NBS and NK models use Silicon Carbide/Silicon Carbide (SiC/SiC) hard-face mechanical seals as standard. This configuration offers excellent wear resistance, even in systems with variable loads, abrasive fluids, or inconsistent chemical concentrations.

The eSiC-07 material used in the seals offers improved tribological characteristics, performing well under friction, heat, and pressure changes, along with broad chemical resistance.

EPDM elastomers allow for a wide temperature range, … and a PEEK-PTFE disk provides self-cleaning properties and adjusts to changing system conditions.

Together, these materials ensure long service intervals and reduce unplanned maintenance.

The Grundfos end suction pumps also come with a range of shaft seal options to suit different applications.

There are two standard configurations:

Rubber bellows seals

O-ring seals

Rubber bellows seals handle pressures up to 232 psi and are robust, cost-effective, and easy to install. The O-ring seals are suitable for more demanding applications.

With pressure resistance up to 363 psi, they are appropriate for booster systems and high-head industrial installations. Both options are modular and field-serviceable, simplifying inventory and allowing quick adaptation in the field.

Installation time can also impact lifecycle cost. Traditional end suction pump installation often requires laser alignment, rack-mounting and wiring variable frequency drives (VFDs), and grouting, each adding a day per pump.

The NBE and NBSE variants eliminate the need for these steps, reducing installation time and cost, while minimising the risk of alignment issues.

Serviceability is another important factor when it comes to end suction pumps. Long-term operating costs are influenced by the time and complexity of maintenance.

All Grundfos end suction pumps feature a back pull-out design, allowing the rotating assembly to be removed without disturbing the piping.

On the NBS pump, a rigid split coupling maintains lifetime alignment and provides rapid access to critical components such as the mechanical seal.

Flexible couplings simplify service and reduce maintenance costs, while spacer couplings allow mechanical seal access without removing the motor.

That covers our overview of the features and benefits of Grundfos end suction pumps.