Smoothing out the sun cream process

For sun creams and lotions to work effectively they must be free from contamination, so manufacturing processes must be as hygienic as possible. At Malibu Health Products an important stage of the process requires the transfer of sun care creams and liquids from 1000 litre vessels. This was being handled by flexible impeller pumps. However, there were issues with the pump impellers wearing rapidly due to the viscous nature of the process fluids. The resulting pump failures led to plant downtime, unplanned maintenance costs and product contamination caused by rubber particles entering process liquids from worn impellers. Furthermore, the use of flexible impellers pulled air into the process and also imparted excessive levels of shear stress onto the liquid, both of which could degrade the end product. 

Options

The key issues of ensuring optimum hygiene and maintaining the integrity of the sun creams and lotions during the transfer process were key factors in determining what type of pump would be most suitable. Furthermore, the requirement for a given amount of flow regardless of differential pressure and the high viscosity of the creams and lotions being transferred, excluded a centrifugal pump from the possible options.

It was decided that a positive displacement (PD) rotary pump would be the best option. However, with four types of PD pumps typically available; internal or external gear, lobe and vane, which would be most suitable? While most PD pumps can be adapted to handle a wide range of applications, some types are better suited to others for a given set of circumstances. Rotary lobe pumps are a popular choice for food and pharmaceutical applications because there operate without metal-to-metal contact so wear in abrasive applications is minimal and potential for contamination is eliminated. Furthermore, since the lobes do not make contact and clearances are not as close as in other PD pumps they are well equipped to handle liquids with high viscosities when operating at reduced speeds. Slow operating speed give the added benefit of minimising shear stress on the product.

Solution

Inoxpa SLR 2-50 sanitary lobe pumps constructed in hygienic 316L stainless steel with 480 rpm geared motors were supplied by Michael Smith Engineers, replacing the flexible impeller pumps. These pumps are designed to handle even the most viscous fluids, such as the sun creams being produced at Malibu Health Products, without the risks of contaminating or degrading sensitive products. 

Benefits

The lobe rotor design ensures smooth, shear-free pumping and low operating speeds and provided immediate energy savings. George Mears, technical manager at Malibu Health Products (Sun Protection), comments: “We are happy with the Inoxpa lobe pumps supplied by Michael Smith Engineers, as we have now have minimal air ingress into the process, no product contamination and reduced maintenance downtime.” 

Inoxpa SLR rotary lobe pumps provide a solution for pumping applications which involve liquids that are highly viscous such as creams, syrups and gels, or those containing solid particles. The positive displacement, sanitary construction meets the strict requirements for processing sensitive, hygienic end-products, making them safe and suitable for use in cosmetic, pharmaceutical, food processing and fine chemical industries. 

The lobe rotor design features large cavities between the lobes to ensure easy handling of viscous liquids with virtually no shear onto the product. 

No parts can wear into the process liquid, so the risks of product contamination are eliminated. Furthermore, low operating speeds enable smooth flows, reduced wear and efficient operation.