The Gorman-Rupp Roto-Prime® RD & RS Series pumps are designed for petroleum products, petrochemicals, and solvents, providing automatic, positive priming to ensure efficient fuel transfer and off-loading.
Roto-Prime® pumps feature a built-in variable capacity vane pump that quickly removes air and vapor, making them ideal for transport loading, unloading, and hose stripping applications.
The Gorman-Rupp Roto-Prime® design ensures uninterrupted fuel transfer by automatically evacuating air and vapor from the suction line during priming or when vapor pockets form:
During priming – The variable displacement vane pump creates a vacuum, drawing in air and vapor and releasing it through the discharge line.
When liquid flow begins – The centrifugal pump takes over once sufficient liquid pressure is established.
Automatic neutral mode – Once priming is complete, hydraulic pressure shifts the vane pump to neutral, reducing wear and prolonging pump life.
Removes air pockets automatically for smooth fuel flow and prevents shutdowns due to trapped vapor.
Rugged ductile iron and cast steel housings provide corrosion resistance.
Extend service life.
Enhance chemical compatibility.
Available in two styles
RS Series – Standard-duty models for typical fuel transfer.
RD Series – High-head models for demanding applications.
Including fluorocarbon mechanical shaft seals.
Base-mounted, motor-driven configurations – For fixed installations.
PTO-driven models – Designed for truck and trailer fuel transfer.
Multiple motor & power configurations – Customizable for operational needs.
Gorman-Rupp RD & RS Series (Roto-Prime®) pumps set the benchmark for fuel transfer, bulk storage, and loading/off-loading operations. Their automatic vapor removal, durable construction, and flexible configurations ensure reliable, uninterrupted fuel movement with minimal service requirements.
A Roto-Prime® pump combines two pump technologies in a single unit: a variable displacement vane pump for priming and a centrifugal pump for liquid transfer. During start-up, the vane pump evacuates air and vapor from the suction line and pump casing. Once liquid flow is established and discharge pressure builds, the vane pump automatically shifts to neutral mode, leaving the centrifugal pump to handle liquid transfer at full efficiency. This design is purpose-built for petroleum products, petrochemicals and solvents.
When air or vapor is present at start-up, or when suction is lost during pumping, the variable displacement vane pump activates automatically. It draws air through the impeller balance holes and body cover, then discharges it via tubing to the volute discharge flange. An integral priming valve prevents air from returning to the suction side. Once the centrifugal pump builds sufficient discharge pressure, hydraulic back pressure pushes the vane pump’s movable slide into neutral. The vane pump remains in neutral until air or vapor re-enters the system, at which point it reactivates automatically.
The RS Series uses a single volute design and operates at a maximum speed of 1750 rpm, making it suitable for standard-duty petroleum transfer applications. The RD Series features a double volute design and operates at speeds up to 3450 rpm, delivering higher head for applications that require greater discharge pressure. Both series share the same Roto-Prime® priming technology and are available in multiple sizes.
RS Series: RS2 (3″ x 2″) up to 305 GPM / 19 l/s, max head 88′ / 27 m. RS3 (4″ x 3″) up to 720 GPM / 45 l/s, max head 136′ / 42 m. RS5 (6″ x 5″) up to 1480 GPM / 93 l/s, max head 156′ / 48 m. RD Series: RD2 (3″ x 2″) up to 324 GPM / 20 l/s, max head 280′ / 85 m. RD3 (4″ x 3″) up to 690 GPM / 44 l/s, max head 276′ / 84 m. RD4 (6″ x 4″) up to 930 GPM / 59 l/s, max head 390′ / 119 m.
No. Roto-Prime® pumps can prime from a completely dry casing. The variable displacement vane pump evacuates air and vapor without requiring pre-filled liquid. Under favorable conditions, a dry 100 mm suction line with zero back pressure can be primed at approximately 6 seconds per meter of suction line length.
Roto-Prime® pumps are designed for petroleum and petrochemical transfer applications, including bulk storage facilities, airport fueling systems, military and fuel depot operations, hydrocarbon processing, and loading or unloading transport vehicles and rail cars. The priming-assisted design also effectively strips product from the suction line, reducing spillage of volatile liquids.
Standard construction includes ductile iron or cast steel housings with an aluminum impeller and a steel or stainless steel shaft. A fluorocarbon mechanical seal is fitted as standard. Optional materials include bronze impellers, stainless steel shafts and fasteners, iron rotors for the priming pump, and specialized mechanical seals for specific liquid formulations. Optional materials should be discussed with your application engineer to match the pump to the specific medium being handled.
Several accessories are available as options: an air release valve (GRP33-08) for reliable priming against moderate to high static heads; stainless steel shafts and fasteners for corrosion resistance; bronze impellers for compatibility with certain petroleum products; companion flanges for simplified piping connections; swing check valves to prevent backflow; and specialized mechanical seals for specific liquid formulations including high-concentration ethanol. All accessories are optional and should be selected based on application requirements.
The variable displacement vane pump removes vapor pockets from the system without becoming vapor locked itself. When vapor enters the suction line or pump casing during operation, the priming pump reactivates automatically, evacuating the vapor and restoring normal liquid flow. This makes Roto-Prime® pumps particularly suited for volatile liquid transfer, where vapor can be present intermittently.
Gorman-Rupp Europe provides application engineering support for pump selection, system sizing and configuration advice from its European facilities. Product support includes operation and maintenance manuals, specification data sheets, performance curves and outline drawings in PDF and CAD formats. Warranties cover up to 60 months. Parts, service and training are available through a network of factory-trained distributors across Europe.
Leave your name and email address below and receive the brochure directly in your inbox.
"*" indicates required fields
Laat uw naam en e-mailadres achter en u ontvangt de brochure direct in uw inbox.
"*" indicates required fields
Laat uw naam en e-mailadres achter en u ontvangt de brochure direct in uw inbox.
"*" indicates required fields
Leave your name and email address below and receive the brochure directly in your inbox.
"*" indicates required fields
