Exploring Gorman-Rupp HDD Dewatering Pumps in Europe
Hydro Innovations General Manager Garry Grant and Finance Manager Karin Grant recently visited Gorman-Rupp Europe in the Netherlands, strengthening Hydro Innovations’ direct relationship with one of the world’s leading pump manufacturers.
The visit provided an opportunity to examine pumping solutions for demanding dewatering applications and discuss how different pump designs perform under difficult operating conditions.
One of the central topics was selecting a durable pump configuration for Horizontal Directional Drilling dewatering, commonly referred to as HDD dewatering.
Finding the Right Pump for HDD Dewatering
HDD projects commonly use bentonite slurry to lubricate and support the bore during drilling. Bentonite can be viscous and abrasive, and the pumped mixture may contain fine solids, sand, gravel or entrained air. Pump selection therefore needs to account for wear resistance, solids passage, reliable priming and performance under changing flow conditions.
Horizontal Directional Drilling projects can present challenging pumping conditions, particularly when the water being removed contains sediment or abrasive material.
Under these conditions, selecting a pump based only on its maximum flow rate may produce a poor long-term result. The pump’s operating speed, internal materials, solids-handling capability, priming arrangement and maintenance requirements must also be considered.
The key technical takeaway from Hydro Innovations’ visit was clear:
Slow-running pumps with hardened internal components are likely to provide the longest service life in abrasive HDD dewatering applications.
A slower-running pump may reduce the rate of wear on critical components. When this is combined with hardened internals selected for abrasive liquids, operators can achieve a more durable pumping solution with fewer interruptions for maintenance.
The correct result will still depend on the individual application, including the liquid being pumped, the concentration and type of solids, the required flow, the discharge head and the pump’s expected operating hours.
Gorman-Rupp 6400 Series Pumps Discussed During the Visit
Two of the specific Gorman-Rupp pumps featured during the visit were the:
- Gorman-Rupp 6404VA71-B
- Gorman-Rupp 6406VA71-B
These pumps form part of the Gorman-Rupp 6400 Series of solids-handling end-suction centrifugal pumps.
The 6400 Series has been developed for municipal, industrial and mining applications and can be configured to pump liquids ranging from clean water to solids-laden wastewater and sludge. The range includes several impeller options and optional hardened internal components for applications involving abrasive pumped media.
The 6404VA and 6406VA are vortex pump configurations within the range. A vortex design can help reduce contact between larger solids and the impeller, depending on the liquid and application.
The featured 6404VA71-B is a 100 mm pump capable of handling solids up to 76 mm, while the 6406VA71-B is a 150 mm pump capable of handling solids up to 102 mm. Both models use ductile iron casings, Gorman-Rupp Hard Iron impellers and silicon carbide seals.
Hardened Internals for Abrasive Pumping Conditions
Pump wear can become a significant cost when abrasive material continuously passes through the casing and across the pump’s internal components.
For this reason, the 6400 Series can be supplied with a range of internal material options, including hardened materials, stainless steel, CD4MCu, high-chrome and other specialised configurations. The appropriate construction must be selected according to the pumped liquid and expected operating conditions.
The series also uses an oil-lubricated mechanical cartridge seal designed for abrasive and trash-handling service. Its removable rotating assembly allows major rotating components to be removed without disturbing the pump volute or connected pipework, helping simplify servicing and reduce downtime.
For contractors and asset owners, these features can be particularly valuable where pumps operate for extended periods or where equipment downtime could delay drilling and construction work.
A Purpose-Built External Priming System
The standard Gorman-Rupp 6400VA pump is an end-suction centrifugal unit. For the HDD systems discussed during the visit, the pumps were paired with a purpose-built external priming system, creating a prime-assisted package suited to changing site conditions.
Priming is an important consideration when a centrifugal pump is positioned above the water source. Before pumping can begin, air must be removed from the suction line so liquid can enter the pump.
An external priming arrangement can help establish this prime without relying entirely on the pumping chamber itself. The appropriate priming system should be selected based on the suction lift, suction-line length, operating environment and whether the pump will be continuously supervised.
Hydro Innovations can assess these requirements and help configure the pump, drive, skid, controls and priming system around the conditions of the individual project.
More Than Selecting a Pump by Flow Rate
Reliable HDD dewatering requires more than selecting a pump that can achieve the required litres per second.
A proper pump assessment should consider:
- The type and concentration of solids in the water
- Whether the pumped material is abrasive
- Required flow and total dynamic head
- Suction lift and suction-line length
- Expected daily operating hours
- Pump speed
- Impeller type
- Internal materials of construction
- Priming requirements
- Access for inspection and maintenance
- Whether the unit needs to be skid-mounted, trailer-mounted or installed permanently
Considering these factors at the beginning of a project can reduce the risk of premature wear, poor priming, insufficient performance and unnecessary downtime.
Bringing Gorman-Rupp Pump Knowledge Back to Australia
Hydro Innovations is Gorman-Rupp’s exclusive Australian distributor for the municipal and industrial markets.
Visits to Gorman-Rupp facilities give the Hydro Innovations team direct access to manufacturer knowledge, product developments and application experience.
This relationship helps Hydro Innovations move beyond simply supplying equipment. The team can work with Australian contractors, engineers, municipalities and industrial operators to identify a pump configuration suited to the actual conditions of the application.
Hydro Innovations also stocks Gorman-Rupp pumps and genuine spare parts in Australia, providing ongoing support after the initial pump has been supplied.
Looking for an HDD Dewatering Pump?
The longest-lasting dewatering solution is not necessarily the pump with the highest operating speed or the largest engine.
For abrasive HDD dewatering applications, a slower-running pump equipped with appropriately hardened internal components may offer a more reliable and maintainable solution.
Hydro Innovations can help assess your flow, head, solids, suction and operating requirements before recommending a Gorman-Rupp pump and priming configuration.
Speak with the Hydro Innovations team about a dewatering pump for your HDD, construction, mining or industrial project.
Call (02) 9898 1800 or submit an enquiry through the Hydro Innovations website.