Lobe Pumps Overview
Lobe pumps are used in a variety of industries such as pulp and paper, chemical, food, beverage, pharmaceutical and biotechnology. They are frequently used in these different industries as they offer excellent sanitary properties, high efficiency, reliability, corrosion resistance, and clean-in-place and sterilize-in-place (CIP/SIP) properties.
Lobe pumps offer a variety of lobe options, including single, two-bladed, three-lobed and multi-lobed. Rotary lobe pumps are non-contact and have large pump compartments to avoid damaging products such as cherries or olives. They are also used to process slurries, pastes and a wide variety of other liquids. Lobe pumps offer self-priming performance if they get wet. A gentle pumping action minimizes product spoilage. They also offer reversible flows and can stay dry for a long time. Flow is relatively independent of changes in process pressure, so output is continuous and uninterrupted.
Rotary lobe pumps, another lobe pump, are used in various sectors from industrial designs to sanitary designs. Healthy designs are further dispersed depending on the service and specific sanitary requirements. These requirements include 3-A, EHEDG, and USDA. The manufacturer can tell you which certifications, if any, are met with their rotary lobe pumps.
How Lobe Pumps Work
Fluid passing through the lobe pump. Lobe pumps are similar to external gear pumps that are actuated in that this fluid flows around the casing. However, unlike external gear pumps, the lobes do not make contact. Lobe contact is blocked by external timing gears in the gearbox. Pump shaft support bearings are contained within the transmission and bearings are outside of the pumped fluid, limited by pressure, bearing position and shaft deflection.
As the lobes exit the cage, they create an expanding volume on the inlet side of the pump. The fluid flows into the cavity and is trapped by the lobes as they rotate.
- The fluid circulates around the stem in pockets between the lobes and the stem – it does not pass between the lobes.
- Eventually, the sticking of the lobes together delivers fluid under pressure from the outlet hole.
Lobe pumps are frequently used in food applications as they handle solids without damaging the product. The particle size pumped may be larger in lobe pumps than in other types of PD. Because the lobes do not touch and the gaps are not as close as other PD pumps, this design handles low-viscosity fluids with reduced performance.
Its loading characteristics are not as good as other designs and its absorption ability is low. High viscosity fluids require low speeds to achieve satisfactory performance. Reducing 25% of the rated speed and below is common for high viscosity fluids.