Flux created the electric drum pump in 1950. Our 75 years of pump design experience shows – Flux F 424 drum transfer pumps are the benchmark in seal-less drum pump technology. Engineered for maximum durability and chemical resistance, these pumps are designed to handle neutral, corrosive and flammable fluids with a maximum viscosity of approx. 1,200 mPas.
Consequently F 424 is ideal for transferring most common, clean liquids from 200-litre drums, IBCs, tanks and process vessels. This pump is the go-to solution for industrial professionals who require high reliability and long service life in demanding chemical and petrochemical environments.
Available in polypropylene, PVDF and stainless steel 316 materials, the F 424 drum transfer pump is a versatile solution for handling almost any liquid – acids, alkalis, solvents, oils and fuels. In addition, stainless steel versions are ATEX-certified for use in hazardous areas where flammable vapours are present.
Firstly, those seeking long-term operational efficiency, minimal maintenance and the lowest whole-life cost, will find the Flux F 424 to be the superior option. Its seal-less design eliminates the requirement for a mechanical shaft seal, thereby mitigating a common cause of drum transfer pump failure.
F 424 incorporates the unique Flux spiral guide bearing – this guarantees shaft stability and bearing longevity, while eliminating the requirement for a mechanical seal in the wetted liquid area. Furthermore, this patented bearing provides optimal drive shaft support at its central point, reducing radial loads that create shaft deflection and vibration.
By their nature, drum pumps have long drive shafts – the better supported the drive shaft is, the lower the chance of shaft misalignment, wear and premature failure. Compare the design of the F 424 pumps with our competitors’ and you will see the difference.
This intelligent bearing design also aids drainage, ensuring that residual liquid does not remain trapped inside the pump tube after use. Moreover, it prevents the build-up any sediments—particularly important in applications that require minimal cross-contamination, or clean-in-place (CIP) capabilities.
In addition, F 424 has a class-leading, 6 mm diameter, reversible drive shaft. This unique feature doubles the service life of the most expensive replacement part. Finally, the serviceable design along with a complete range of individual spare parts, puts F 424 far ahead of any competitor.
These drum transfer pumps excel in handling pure, non-crystallising, solids-free media across a broad range of pH levels and temperatures.
To help decide, engineers should consider the four steps below:
Firstly, consider material selection: Use PP or PVDF pumps for acids, alkalis, and oxidisers, or 316 stainless steel for hydrocarbons and flammable solvents. In addition, ensure the temperature of the liquid is compatible with the desired pump material.
Viscosity: For pure fluids below 1,200 mPas, the F 424 is ideal. For thicker fluids, consider F 570 or F 580 progressive cavity IBC and drum pumps.
Presence of solid particles, crystals or abrasives: If the liquid contains a high quantity of solid particles, then consider the F 430 pump.
F 424 is available in the following standard lengths – 700 mm for smaller containers, 1000 mm for 200-220 litre drums, 1200 mm for 1000-litre IBCs and 1500 mm for deeper process tanks. Select the correct immersion length for the container. Also consider the diameter of the container opening.
Consider the preferred power source for the drive motor – F 424 is predominantly used with our 230 V or 110V single-phase electric motors, or compressed air motors. However, DC powered electric motors are also available for special applications.
Check if the pump will be used in a zoned, explosion hazard area, food production area, or corrosive atmosphere, as this will influence motor selection. If the pump is to be used in a noise sensitive area, consider a totally enclosed F 458 motor.
The F 424’s modular motor compatibility also allows users to switch between electric, compressed air, or brushless drives to meet energy supply, or safety requirements.
Lastly, if the pump is to be used regularly and for long periods, the F 424 is a good choice. This pump can deliver high flow and discharge pressure (especially if the semi-axial, z-impeller option is selected). Plus there is a wide range of accessories available, such as hose, hose connections, hand nozzles, suction strainers, flow meters and fume suppression devices.
These drum pumps are remarkably similar in appearance and intended use. However, their internal design and application suitability is quite different.
Both pumps are centrifugal, axial impeller designs that are:
*Measured with water at 20 degrees C in open flow condition. The maximum figures listed above are dependent on the application, fluid properties and pump-motor configuration. Please refer to technical data sheets or performance diagrams.
Therefore, consider the factors below in order to make the correct selection for your application:
Consideration of the points listed above will help you decide whether F 424 or F 430 is required for your application.
Firstly, the two lateral slots near the inlet of the F 424 pump are known as pressure equalisation ports. As liquid enters both the inner and outer pump tubes, these ports allow pressure to stabilise between the two tubes. They are also necessary to facilitate drainage of the inner tube. When the liquid level in the drum falls below these ports, a small amount of liquid can be seen flowing from the ports under pressure.
This behaviour is typical for centrifugal seal-less drum pumps of this type and is nothing to be concerned about. This is because the pump can no longer operate once air enters the pump inlet and the impeller is no longer submerged. When the pump is switched off, as residual liquid held in the pump tube (and potentially the discharge hose) during operation, drains back into the drum.
This can comprise several litres of liquid, therefore creating the appearance that the pump has not emptied the drum. A residual quantity of liquid (approximately 10 mm depth) will always be left. This is a known limitation of most axial impeller drum pump designs, such F 424.
If minimising leftover liquid is critical to your process, we recommend:
The Flux F 424 is a centrifugal immersion type drum pump that uses the kinetic energy of a high-speed rotating impeller to generate fluid movement. Firstly, it relies on atmospheric pressure to push liquid to the impeller – the pump does not suck up liquid. The impeller spins within the lower pump housing, energising the liquid and driving it up through the pump tube, before expelling the liquid through the side discharge port.
What distinguishes the F 424 is its seal-less design. The pumped fluid flows into the inner tube (which houses the drive shaft and bearings) and rises to the same level as the fluid in the drum. As liquid is dispensed, the level inside both the container and the pump naturally drops.
Importantly, this design eliminates the requirement for a mechanical shaft seal – a wear part that requires preventative replacement, to eliminate leakage risk. Once emptying is complete, the drive motor is shut down and any residual fluid drains fully through the pump inlet. Additionally, the pressure relief openings, thereby leaving minimal residue inside the pump.
The unique F 424 spiral guide bearing plays a crucial role in this process by centralising the shaft, reducing radial play and eliminating turbulent flow. This improves energy efficiency and protects both the bearings and the impeller from premature wear, even in continuous duty cycles. The spiral design also promotes drainage and ensures that liquid does not remain trapped inside the inner pump tube.
To discuss your application or learn more about the F 424 seal-less transfer pumps, contact our sales team today or head over to our shop here.
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