Horizontal Directional Drilling (HDD) has revolutionised how underground pipelines and cables are installed. By eliminating the need for open trenches, it reduces surface disruption, traffic closures, and restoration costs. At the heart of every efficient HDD setup is one crucial component: a reliable bentonite pump.

Bentonite, a clay-based drilling fluid, lubricates the bore, stabilises the hole, and carries drill cuttings to the surface. Handling this heavy, abrasive fluid requires durable, high-performance pumps that can maintain flow and pressure under harsh conditions. That’s exactly what Gorman-Rupp delivers.

The role of bentonite pumps in HDD

During horizontal directional drilling, bentonite pumps are responsible for:

• Circulating drilling fluid between the entry pit and recycling unit
• Managing variable flow rates during pilot boring, reaming, and pullback
• Handling abrasive slurry without clogging or loss of performance

Simply put, the pump is essential in any drilling operation. It must be reliable, wear-resistant, and ready for continuous operation.

The challenge of pumping bentonite

Bentonite slurry is thick, viscous, and abrasive. It wears down impellers, causes blockages, and can trap air in the suction line. Pumps often need to handle intermittent flow or even prologued dry-running periods, all without losing efficiency or reliability.

A pump failure can halt an entire HDD operation. That’s why Gorman-Rupp’s S-Line and E-Line PAV4 and PAV6 pumps were developed specifically for bentonite and HDD applications. These dry self-priming vortex pumps combine robust construction, intuitive operation, and low maintenance demands.

Built for continuous operation

In HDD environments, pumps often run 24/7 under variable loads. The PAV-series maintains consistent performance even during stop-and-go operation. Large oil baths, efficient cooling, and precision seals prevent overheating and cavitation.

Beyond HDD applications

While developed for HDD, Gorman-Rupp bentonite pumps are equally suited to mining, tunnelling, civil engineering, wastewater bypass, and industrial slurry applications.

Built on experience, engineered for reliability

With nearly a century of pump engineering expertise, Gorman-Rupp continues to set the standard for performance and reliability. From our European headquarters in Waardenburg, the Netherlands, we provide local service, spare parts, and technical support.

Contact Gorman-Rupp Europe today, our experts will help you find the right setup for your project.

Why choose Gorman-Rupp bentonite pumps

1. Dry self-priming vortex design – The PAV4 and PAV6 pumps use a vortex impeller that allows solids to pass freely. The built-in vacuum or compressor-venturi system enables quick priming even with an empty suction line.
2. Proven wear resistance – Abrasive materials like sand and gravel are no match for the reinforced impeller and casing.
3. Built for heavy-duty environments – Fully welded, hot-dip galvanised steel chassis provides maximum strength.
4. Easy maintenance – Quick service without dismantling pipework.
5. Unsurpassed priming : Gorman-Rupp’s proprietary TPAWS priming systems enables fast and trouble free priming under all conditions.
6. Sustainable power options – Stage V diesel or electric drive for low-emission operation.

The E-Line is Gorman-Rupp Europe’s electric mobile pump set range, built for projects where on-site emissions, noise levels and precise speed control matter. With an integrated variable frequency drive (VFD), easy to use controls and a whisper-quiet sound profile, the E-Line meets the requirements of urban infrastructure work, zero-emission zones and industrial sites where grid power is reliable. Built on the same proven self-priming pump technology as the diesel driven S-Line, the E-Line delivers comparable hydraulic performance with zero on-site CO2 emissions.

Built on the same proven pump platforms

The E-Line uses the Gorman-Rupp pump platforms as found in the S-Line series. This means hydraulic performance is largely comparable; you do not trade away flow, head or solids handling capability when you switch to electric. The same Eradicator and Eradicator Plus solids management systems are available, the same multi-vane or Vortex benefits, the same external shimless adjustment and cartridge seal technology and of course the TPAWS priming system on our prime-assisted models.

Integrated variable frequency drive and intuitive controls

The integrated VFD provides soft-start, energy-efficient part-load operation and continuous speed control. You can match pump speed precisely to required duty point at the application, which means lower energy consumption, less wear and a quieter sound profile. Soft-start eliminates the inrush current spike that on direct-on-line motor starts can disturb other site equipment or trip protection devices.

Controlling the E-Line pump sets is done through an intuitive control panel, making operating an E-Line electric sets just as easy as the diesel driven sets you are familiar with.

Zero on-site CO2 emissions

The E-Line produces no on-site CO2 emissions. For projects in zero-emission zones, in protected nature areas, in dense urban centres or inside industrial buildings, this is often a regulatory requirement, not a preference. Combined with electricity from a renewable source, the full lifecycle emissions are minimal.

Whisper-quiet operation

Sound levels on the E-Line are low enough to allow night-time operation in residential areas, work near hospitals and schools, and use inside enclosed industrial buildings without specific sound attenuation. This widens the operating window for projects that previously required complex noise mitigation.

Stackable design

The E-Line is engineered for compact storage and transport. The stackable enclosure design saves yard space, simplifies fleet logistics and allows efficient transport on standard trucks.

Service-friendly and durable

Like the S-Line, the E-Line uses removable cover plates, external shimless wearplate adjustment on most models and cartridge seal technology. Electrical components are housed in a protected control panel for easy access during inspection and service.

Typical applications

Construction dewatering with grid power available. Urban sewer bypass during gemaal repairs. Industrial process duties inside facilities. Permanent or semi-permanent installations where mobile flexibility is still needed. Operations in zero-emission zones. Projects with strict night-time noise limits.

Warranty and support

Up to 5 years warranty depending on model and terms. Supported by European assembly and testing, commissioning support, training through Gorman-Rupp Academy and parts logistics across Europe.

Frequently asked questions

The S-Line is Gorman-Rupp Europe’s diesel-driven mobile pump set range, designed for sites where autonomy, transportability and continuous operation under demanding conditions matter most. The S-Line carries its own fuel, starts independently of grid power and runs through nights, weekends and storms with minimal supervision. Built on proven Gorman-Rupp self-priming pump technology and a Stage V emissions-compliant diesel engine, it is the platform of choice for construction dewatering, sewer bypass, HDD and emergency response.

Built on Gorman-Rupp pump technology

The S-Line is engineered around the Gorman-Rupp self priming pump platforms. Self-priming centrifugal pumps that automatically evacuate air from the suction line and re-prime without operator intervention. Gorman-Rupp pumps excel in heavy duty applications. The Eradicator and Eradicator Plus solids management systems available on many models handles stringy materials such as rags, wipes and fibrous sludge. Prime-assisted and Vortex Pumps are specifically designed for though applications like mining and construction.

Stage V diesel: emissions and HVO compatibility

The Stage V engine is the current EU emissions standard for non-road mobile machinery. It substantially reduces particulate matter and NOx versus earlier stages and is mandatory on most regulated infrastructure projects. The S-Line engines are HVO-compatible without modification, allowing customers to lower CO2 emissions by up to 90 percent by using renewable diesel. This combination of Stage V plus HVO meets the emissions criteria set by most European clients today.

Service-friendly construction

Gorman-Rupp’s design philosophy puts maintenance access first. The removable cover plate on many models gives direct access to the impeller and volute for inspection or wear part replacement, without disconnecting suction or discharge piping. External shimless adjustment lets you reset the wear plate clearance in the field with hand tools, restoring performance without dismantling the pump. The cartridge seal technology allows seal replacement as a single unit, reducing service time and the risk of incorrect reassembly.

Configurations

The S-Line is deigned for easy road transport between sites, and provides sound-attenuated versions for noise-sensitive projects. Discharge sizes typically range from 2″ to 16″, with capacity windows from approximately 30 to 2.500 m3/h depending on the pump platform. Fuel tanks are sized for typical run times of 24 to 72 hours; larger external tanks can be connected for unattended weekend operation.

Typical applications

Construction dewatering, sewage bypass during pumping station repair, HDD slurry handling, mine dewatering, irrigation and emergency flood response. The S-Line is also widely used in rental fleets.

Warranty and support

Up to 5 years warranty depending on model and terms. Backed by European assembly and testing, commissioning support, training through Gorman-Rupp Academy and a 24/7 service network. Spare parts are stocked locally for fast turnaround.

Frequently asked questions