Drum & Barrel Pump Useful Information

Drum pumps (also known as barrel pumps) are portable devices used for emptying drums, barrels, IBC tanks and smaller containers. These pumps are long and slim – they are designed to stand on the bottom of the vessel. They are lightweight and easy to insert into narrow barrel openings or open-topped containers. Typically, they consist of a drive motor or hand-operated mechanism, a rigid pump tube (also known as a pipe, lance, wand, or stick), a hose assembly and a nozzle or spout for dispensing fluids. To operate, simply insert the pump into the drum, enabling liquid to be pumped from the bottom of the container. 

The type of fluid, i.e. its rheology, density and viscosity, as well as the desired flow rate and discharge pressure, all influence barrel pump selection. You can choose from various body, driveshaft and o-ring materials, to ensure compatibility with the fluid being pumped. Additionally, several types of drive motors are available, e.g. compressed air, electric or battery powered. 

These pumps deliver efficient and safe liquid transfer, reduced risk of spills or leaks and allow for controlled flow rates during dispensing. 

Hand-operated drum pumps generally use a lever or rotary handle operated suction mechanism, while powered pumps are usually, but not exclusively, positive displacement or centrifugal designs. Positive displacement models, such as Flux progressive cavity pumps, create suction to help draw product into the pump inlet.

They can be described as self-priming pumps, however, in a typical drum application (with the pump standing on the bottom of the container), liquid flows under gravity to the pump inlet. Therefore, these pumps are ideal for pumping viscous materials, as the suction effect combined with gravity assisted flow, both help to fill the pumping chamber with fluid. This is a significant benefit when compared to surface mounted, self-priming designs, such as air-operated double diaphragm (AODD) pumps.  

Vertical centrifugal drum pump designs (e.g. Flux F 300 and F 400 models) are not self-priming – they rely on the impeller being immersed in the fluid to operate. When the container is nearly empty, air will enter the pump and liquid flow will decrease to zero. The pump will start to run dry. Motor speed will increase, as the motor is no longer operating under pumping load. The operator will notice an increase in noise produced by the drive motor. At this point, the pump should be switched off to avoid damage through overheating. 

Air powered drum pumps are primarily used to transfer liquids from one vessel to another, just like other types of barrel pumps. They consist of a pneumatic drive motor and a close-coupled pump tube. Expanding compressed air drives the pneumatic motor. 

Subsequently, the expanding air turns rotary vanes inside the motor at high speed, typically up to 10,000 RPM. This energy is converted into rotary mechanical motion in the pump. Pneumatic motors can be used to drive both centrifugal pumps (for low viscosity fluids) and positive displacement pumps (for high viscosity fluids). A low-ratio gearbox is sometimes used to reduce rotational speeds to <1000 RPM when powering positive displacement pumps. 

Pneumatic drum pumps are ideal for transferring flammable fuels and solvents. Additionally, you can use them in heavy-duty applications and for handling large volumes. Constructed from conductive stainless-steel 316 tubes, these pumps are also useful for transferring flammable media of various hazard classes, in hazardous environments. Flux barrel pumps and air motors are ATEX approved, therefore guaranteeing safe operation in Zoned areas with dangerous levels of explosive gas or vapour. 

A drum pump and a barrel pump are the same type of industrial transfer pump. The two terms are used interchangeably. Both names describe a portable pump with a long, narrow pump tube designed to reach the bottom of containers such as 55‑gallon drums, steel barrels, plastic drums, IBCs, open tanks and similar vertical vessels.

They share the same modular architecture, typically consisting of a drive motor (electric, pneumatic, or battery powered) coupled to a pump tube that uses either a centrifugal impeller (for low‑viscosity fluids) or a positive‑displacement rotor-stator combination (for higher‑viscosity fluids).

Because the pump’s geometry, materials and performance characteristics are identical regardless of the name, engineering specifications focus instead on preferred power supply, fluid viscosity & density, chemical compatibility, required flow rate and discharge pressure, duty cycle and safety or regulatory requirements. For example, ATEX or food approvals. The dual terminology exists mainly due to regional language differences but in practice, both names refer to the same pump family.

The Flux barrel pump range is used in every industry, however, they are commonly used in the manufacturing and dispensing of chemicals, cosmetics, pharmaceuticals, oils, lubricants and food beverage products. In addition, you will find them in oil gas production facilities, plus agricultural, marine and water treatment applications.

Visit our pump by industry page, to find your industry and consequently the Flux pumps we recommend for your specific applications.

Our drum barrel pumps comprise of three main parts: the motor, the pump tube and the hose connection. Assembly is simple and user-friendly. First, unbox the products. Note that the pump tube is supplied with a captive union nut with female thread. The lower motor housing has a matching male thread. Attach the pump tube to the motor. The motor driver will automatically engage with the recessed coupling star in the top of the pump. Tighten the pump union nut to the motor by hand, ensuring a secure fit.  

Attach the discharge hose (can be supplied by Flux or others) to the hose connection and secure with a suitable hose clamp. The hose connection has a captive union nut with female thread. Connect the union nut to the male threaded discharge port on the pump and tighten. If the pump is to be used with low flash-point flammable liquids, or inside an ATEX zoned area, ensure that earth cables are connected securely (if required) and that earth bonding has been checked.  

Now the pump is ready to be placed into the barrel or IBC container.  

Our most common F 300 and F 400 series drum barrel pumps are centrifugal designs. These pumps create limited suction once primed and producing flow, but they cannot dry prime. Flow will only begin if the liquid level in the barrel is above the level of the impeller. The impeller is positioned approximately 7-8 mm away from the bottom of the barrel. Once the liquid reaches this level, air will enter the pump, and it can no longer work.

At this point, the load on the pump impeller will decrease and motor speed will increase. This van be noticed by an increase in noise output from the motor. The operator should turn off the pump to avoid dry running, otherwise it may overheat. This is particularly important when using pumps that are fitted with a mechanical seal.

When the pump is switched off, residual liquid inside the pump tube will drain back into the barrel. The depth of the remaining liquid will correspond to the level of the impeller, i.e.. 7-8 mm. If drain-back is undesirable, for example, the liquid is of particularly high value, or disposal costs are high, consider our F 425 model with back-flow valve. This pump will ensure that 99.9% of the liquid is removed from the barrel.

Flux Pumps are considered the world’s best barrel and drum pumps. We offer class-leading designs with many unique features and benefits: 

By combining durability, versatility, efficiency, safety, ease of use, innovative technology and customisation, Flux provides unmatched solutions for barrel and container pumping applications. Therefore, Flux is the no. 1 choice for businesses seeking reliable, high-performance barrel pumps. 

Spiral bearing  

Our seal-less pumps utilise our unique spiral shaft bearing, even our light-weight F 300 series pumps. This bearing supports the centre section of the driveshaft. Its comparatively high surface area is designed to reduce deflection and vibration that occurs with lesser pumps with conventional bearings.  Vibration increases wear throughout the pump, eventually leading to failure. 

6 mm driveshaft 

Our FP 424 series seal-less barrel pumps are fitted with strong 6 mm diameter driveshafts, designed to minimise deflection at high speeds. The shaft is also reversible – when rotated, the shaft bearings will locate at different positions on the shaft, rather than continuing to wear the same areas of the shaft as before. Therefore, the service life of the shaft is effectively doubled. 

Oversized bearing housing 

The Flux FP 424 barrel pump has an oversized lower bearing housing with four thick bushing rings. This ensures radial loads are distributed across a large area when the impeller is spinning at high speeds.  

Special lengths 

Flux are experts in manufacturing vertical pumps. We have design expertise, manufacturing tooling and production experience that allows us to create pumps in special lengths. This includes short pumps for use where space is limited, such as emptying trays, or for incorporation into OEM products. In addition, our unique design features such as steel-cored inner tubes, allow us to manufacture pumps up to 3,000 mm long.  

These unique design features, combined with our manufacturing capability, class-leading durability and readily available spare parts, means that Flux leads the way in whole-life ownership costs. Why spend money replacing pumps when you can repair and save? We have proven that investing in a Flux F 400 pump is a truly sensible decision for any business.  

Steel-cored inner tubes 

Our F 430 plastic barrel pumps in polypropylene and PVDF have unique steel-cored inner tubes.  The steel core is over-moulded with plastic, giving the pump a huge advantage in terms of strength, bearing support and vibration resistance. In addition, the rigid inner tube provides optimal support to the mechanical seal assembly. The seal remains stable when running at high speeds, or when operating at high temperatures. When combined with a comprehensive range of spare parts, Flux can claim to manufacture the only truly serviceable plastic barrel pump.    

Once the pump is placed into the barrel, ensure the discharge hose is positioned securely in the container to be filled. Various accessories for ensuring safe filling operations are available. These include hand nozzles, non-return valves, discharge spouts and fume cones. Each of these accessories will require separate consideration.  

The pump is now ready to be switched on, using the recessed on-off switch on the motor. Assuming the discharge hose is open-ended, flow will start immediately and liquid will begin filling the container. Some motors have built-in speed control switch, which is used to vary the flow rate. Once the desired quantity has been dispensed, the motor can be switched off.  

Residual liquid left in the discharge hose will continue to drain into the container until the hose is empty. If this is undesirable, consider fitting a handle nozzle or non-return valve, both of which will ensure residual liquid remains in the hose.