Rotary Lobe Pumps Research Articles

Влияние вязкости жидких пищевых продуктов на производительность кулачковых насосов (на примере перекачивания рыбного жира)

Lobe pumps do not damage the structure of a highly viscous substance. Therefore, the lobe pumps are increasingly used for pumping the liquid food products, despite the high cost. For selecting the rotary lobe pumps, the dependences of the productivity on the pressure drop are necessary. Some manufacturers of the lobe pumps post online the dependences of these characteristics on the rotor speed. There is considered a method developed for calculating the performance diagrams of lobe pumps (Q–P) subject to the influence of the viscosity of pumped liquid food products based on the results of the tests. For example, the characteristics of WEB RF-024, Pomac PLP 1-1.5 when pumping fish oil are considered. The analysis of the test results showed the need to take into account in the calculations the minimum speed 
 of rotation of the rotor n0, at which pumping of the liquid begins. It is stated that the minimum rotational speed n0 is 
 a nonlinear function of pressure drop. The volume of liquid pumped in one revolution does not depend on the pressure drop. The volume of liquid with high viscosity pumped in one revolution does not depend on the pressure drop. An in-crease in the temperature of fish oil leads to a decrease in the performance of the lobe pump.

Evaluating shear in perfusion rotary lobe pump using nanoparticle aggregates and computational fluid dynamics.

Perfusion cell culture technology has gained a lot of interest in recent years in the biopharmaceutical industry. One common application is N-1 perfusion which is used to intensify fed batch production processes and increase facility output. Upon running our perfusion process for the first time at manufacturing scale, unexpected cell damage was observed. Reducing the recirculation pump speed resulted in improvements in cell viability which implied the impact of pump shear stress on cell viability. In this study, we used polymethyl methacrylate (PMMA) nanoparticles to determine the shear stress inside two different sized rotary lobe pumps used in N-1 perfusion. The results were used to validate a computational fluid dynamics (CFD) model to predict the maximum shear under different operating conditions of the pump. The CFD model identified the radial and mesh clearance zones as regions that experience the maximum shear stress inside the pump. The model was then used to evaluate the impact of different geometry modifications in the pump lobes, and it predicted a 17% reduction in the maximum shear stress by increasing the mesh and radial clearances by 0.08mm and 0.13mm, respectively. The study indicates that CFD can be a useful tool to predict shear stress inside rotary pumps. The results can be used to optimize the pump operating conditions or even customize the pump geometry to save time and cost of process scaling to manufacturing without compromising the preset operating conditions or critical scale-up parameters.

Verder expands in South Korea with pump company acquisition

The Verder Group has bought JEC Ltd, a South Korean manufacturer of hygienic rotary lobe, centrifugal and twin-screw pumps and blending systems.

A new curve for application to the rotor profile of rotary lobe pumps

This paper proposes a new type of curve, an elliptical roulette, which it initially applies to rotary lobe pumps. Once the new rotor profile has been mathematically modeled using the principle of gearing, equations can be derived to assess the presence or absence of undercutting in the tooth profile. The effect of the new profile properties on pumping performance is evaluated using a specially developed three-dimensional fluid analysis model. The proposed curve is tested using six novel rotor profiles based on the elliptical axial ratio parameter λ (a shorter axis divided by a larger axis). These six new cases and a traditional case are analyzed under the same volume and clearance conditions and their differences compared. The results show that a smaller elliptical axial ratio design produces better flow characteristics. In particular, an elliptical axial ratio smaller than 0.6 not only achieves high discharge efficiency but allows vibration and noise to be controlled by the flow rate fluctuation coefficient, which approximates the traditional indicator. The proposed curve can thus serve as a useful reference for pump or rotary fluid machine design.

Rotary lobe pumps run like clockwork

As a result of its consistency, oil is a medium that places demanding requirements on pumping technology. Suitable pumps must also reliably convey highly viscous materials and provide a high capacity in very limited spaces, such as tankers, as Paul Krampe, head of development at rotary lobe pump specialist Vogelsang explains.

Modeling shear‐induced CHO cell damage in a rotary positive displacement pump

Rotary lobe pumps are commonly used in the biotechnology industry for a variety of purposes. Shear damage to animal cells within the rotary lobe pump can adversely affect the product yield or purity during, for example, cell concentration via cross-flow filtration. In this research, CHO cells grown in 20-L bioreactors were fed to a rotary lobe pump in both single pass and recycle experiments were conducted at different RPMs and "slip" conditions. The results indicate that the slip flow rate more severely impacts the viability of the CHO cells than the pump RPM. A novel mathematical modeling approach is presented that predicts shear rates in all of the positive displacement pump's slip regions, and then predicts cell death vs. operating conditions. This model accounts for the complex flow situation that results from changes to RPM, backpressure and pump geometry (i.e., clearances).

Injection housing – optimising rotary lobe pumps for liquids with high solids content

Today, rotary lobe pumps are used increasingly for pumping liquids with solid particles and during the last 20 years they have gained market share among positive displacement pumps. Manufacturer Hugo Vogelsang Maschinenbau GmbH attributes the pump's success to a well thought out design and wear-resistant materials, enabling them to handle aggressive media more efficiently.

Rotary lobe pumps – a piece of history

One of the earliest examples of rotary lobe pump evolution has recently been returned to its birthplace in Eastbourne, UK to be has restored to its original condition and displayed in Alfa Laval's pump museum. This prompted the company's product support manager, Tony Marshall, to investigate how technology has evolved since this pump was first built and sold over 50 years ago.

Gap leakage behaviour of helical vane rotary lobe pumps

Double-shaft, rotary lobe pumps are often used for conveying slurries in liquid manure, biogas and sewage plants. Mechanical wear enlarges the gaps and decreases the effective flow rate. In this contribution, Meno Turk of Leibniz-Institute for Agricultural Engineering and Burkhard Verhulsdonk of pump manufacturer Hugo Vogelsang Maschinenbau discuss a study in which the effects of wear on the pumping behaviour of helical rotary lobe pumps were systematically analysed, its influences evaluated and new technical solutions for wear compensation were developed.

Rotary lobe pumps from Boerger

Rotary lobe pumps from Boerger

Increasing the operational lifetime of rotary lobe pumps

It is now possible to increase greatly the operational lifetime of rotary lobe pumps by using a multi-wing lobe geometry. This may be achieved without adversely affecting pump efficiency and will reduce overall operating costs, explains Burkhard Verhuelsdonk of German company Hugo Vogelsang Maschinebau GmbH.

Rotary lobe pumps installed on ‘produced water’ duty

Boerger, through its UK distributor Axflow Ltd, recently supplied its Maintenance-in-Place (MIP) PL100 rotary lobe pumps to Talisman Energy Limited for application on the company's Nigg and Buchan offshore oil and gas platforms in the North Sea for a ‘produced water’ duty.

Auslegungsprogramm zur Erhöhung der Nutzungsdauer von Drehkolbenpumpen

Two-shaft rotary lobe pumps are often used for pumping suspensions with coarse matter, i.e in liquid manure, biogas and sewage treatment plants. Pump characteristics change considerably with increasing wear. Based on a mathematical model for wear-caused internal leakage, a new calculation programme for Computer Aided Pump Selection was developed, which combined with the well known programme for calculating pressure drop in pipes, makes it possible for the user to design a complex agricultural pumping system.

Verschleißkompensation bei Drehkolbenpumpen

Rotary lobe pumps are often used for pumping slurry in manure, biogas and in sewage treatment facilities. Here wear occurs and backflow losses inside the pump increase with time. Wear can be reduced through the use of designed components. The effects of some technical solutions for wear compensation were studied and evaluated.

Das Kavitationsverhalten von Drehkolbenpumpen

The cavitation behaviour of rotary lobe pumps is of considerable importance in pump design. Cavitation leads to unstable pumping conditions and causes typical noises. It is always found at zones with maximum flow velocity. Important influential variables on cavitation behaviour, such as rotational speed, lobe wear, fluid viscosity and discharge pressure, are analysed and evaluated.

Running rotary lobe pumps at high speeds

Rotary lobe pumps are claimed by manufacturers to be most economical when run at high speeds. Having previously been examined in scientific trials, this claim has now been subjected to field trials. Carsten Wenner Dipl.-Ing (FH) Hugo Vogelsang Maschinenbau GmbH Co. reports on the most significant results of this field test.

Improved pump for the food and drink industry

APV has re-launched two of its DW range of rotary lobe pumps with enhanced performance characteristics for the food and beverage market. Visit www.worldpumps.com for the latest pump industry news

Verschleißeinfluss auf das Förderverhalten von Drehkolbenpumpen

Zweiwellige Drehkolbenpumpen werden haufig zum Fordern vonSchlammen in Gulle-, Biogas- oder Klaranlagen eingesetzt. Mit zuneh-mendem Verschleis vergrosern sich die Spalte und damit auch die Ruck-stromungsverluste in der Pumpe. Die Auswirkungen auf das Forderver-halten von schrag verzahnten Drehkolbenpumpen wurden systematischuntersucht und die Einflussgrosen bewertet.

Pulsation-free rotary lobe pumps

Pulsation-free rotary lobe pumps

Matching positive displacement pumps to hygienic processes

Although the centrifugal pump remains the workhorse of the process industry, positive displacement pumps have particular specialised benefits and are widely used in a variety of applications. PD pump designs are much more varied than centrifugals and use a whole range of pumping principles:- rotary lobe, peristaltic, progressive cavity and flexible impeller pumps, for example. Each of these have particular advantages, and the individual application should be considered carefully when making a choice. One general benefit shared by all three principles is a gentle pumping action which allows shear-sensitive fluids to be pumped with minimal damage. For this reason, these pump types are frequently considered for applications in the food, beverage, pharmaceutical and biotech industries. Pumps used in these industries, however, must be hygienic.