Key points
With many process fluids, chemicals and food stuffs being stored in containers around the plant having the right barrel or IBC pump becomes essential as you look to upscale production. From productivity gains to a reduction in waste and spills, to more accurate volume transfer and a pure, consistent final product, an efficient container emptying pump can improve your process and bottom line!
The nature of your fluid means that an impeller style barrel pump may do the job nicely, but when that fluid presents some challenges, a progressive cavity design becomes the viable solution.
Progressive cavity pumps, otherwise referred to as helical rotor or eccentric screw pumps, are part of the positive displacement pump family, meaning they move fluid by trapping a fixed volume and forcing that trapped fluid into the discharge pipe.
The progressing cavity working principle in particular consists of a spiralled helical rotor (like a cork screw), which sits tightly inside a rubber stator. As the rotor turns inside the stator, it forms a set of fixed-shaped cavities that progress along the length of the stator and force the fluid inside to move along with them as they turn.
So, now we understand what a progressive cavity pump is. What are some examples of the challenges that may see you opt for a progressive cavity barrel pump?
Shear sensitive fluids that change under force
Under force, delicate fluids can change viscosity like cream being whipped, change consistency like shampoo frothing, or their solids can be crushed, like fruit pieces in a yoghurt. Unlike certain designs like centrifugal pumps, progressive cavity pumps apply low shear due to their low internal velocity and wider tolerances between their pump casing and moving components. This means they will keep your shear sensitive fluids intact, preventing inconsistencies within your product and costly waste.
Highly viscous, “difficult to pump” products
Impeller style barrel pumps are often limited to low viscosity fluids such as chemicals, water-based fluids and light oils. Trying to pump products like Vaseline, resin or tomato paste can be virtually impossible, or you may see it slowly dripping out bit by bit. The viscosities that progressive cavity pumps are able to efficiently handle are amongst the highest of all pump designs thanks to their high pressure capabilities and low internal velocities.
When it comes to progressive cavity pumps, flow rate is unaffected by the viscosity of the fluid and the volume dispensed from the container is determined only by the pump’s capability and speed of the motor. Not only does this mean that you are able to achieve maximum duty even when handling thicker products, but that you can expect to delivery consistent amounts even when a fluid can vary slightly in terms of viscosity.
Presence of solids
Fluids containing solids pose an immediate challenge for many pump designs that have close tolerances inside the pump. However, the continuous cavities that exist between the rotor and stator of the progressive cavity design and the slight flexibility of the stator means that even large solids and abrasive fluids can be handled without clogging or damage caused to the pump.
As previously discussed, their low shear operation also means that progressive cavity pumps are also able to pass such solids without crushing them. This is important for fluids where the solid is not waste such as vegetable chunks in soup.
Highly accurate dispensing
When very specific volumes need transferring from the container, perhaps to fill another container, high accuracy is required which the progressive cavity design can offer. As the fluid progresses through the overlapping cavities steadily at a predictable rate, fluid is delivered smoothly and free of pulsations.. Less pulsations in the flow of fluid also limits the amount of stress the other components in the installation are put under.
Strict hygiene standards
When the product you are producing is for human consumption, hygiene standards of the equipment used is vital. Thanks to the minimal dead space in the progressive cavity barrel pump design and the electropolished stainless steel surfaces the wetted parts can be constructed of, food grade standards are upheld.
Capable of handling delicate, highly viscous, solid laden or abrasive fluids, dispensing them accurately and safely, progressive cavity pumps really do tick the boxes of many challenging applications. And that’s why progressive cavity barrel pumps are perfect for where other container emptying pumps fail!
