Recontamination Prevention in Infant Formula Production: Process Membrane Pump Ensures Compliance with High Hygiene Standards

For the promotion of milk powder concentrate, HOCHDORF has recently been using a Triplex G3F hygienic process membrane pump from the experienced pump manufacturer LEWA. (Source: LEWA GmbH)

The G3F is equipped with a total of three M9 pump heads specially selected for aseptic application at HOCHDORF. These are characterized by their PTFE sandwich membranes, which guarantee high operational safety with comparatively low maintenance requirements. (Source: LEWA GmbH)

Manufacturers of baby and toddler milk-based nutrition must ensure the highest purity standards, consistent quality, and optimal process safety in their production facilities. The risk that hygienically unsuitable plant components could recontaminate the final product is significant. For this reason, strict requirements regarding hygiene and material approvals for production equipment are in place. To better meet these demands, HOCHDORF Swiss Nutrition AG – a Swiss producer of early and follow-on milk – installed a new hygienic high-pressure pump to reliably and safely convey the produced milk concentrates, as well as to dose and process them accurately. Unlike the previously used piston pump, the hermetically sealed membrane pump does not require piston lubrication, significantly reducing the risk of recontamination of the final product by the system. The company chose a process membrane pump of the type Triplex G3F in aseptic design with manifold piping and pressure transmitter solution from LEWA GmbH. This pump is designed for the necessary pressure to spray the concentrates in the spray tower and is additionally characterized by its hermetically sealed membrane pump heads, its particularly powerful drive, and low noise emissions. The unit has been in trouble-free continuous operation since April 2017, greatly reducing the recontamination risk.

"Due to the high hygiene requirements in the production of children's and infant nutrition, continuous adjustments to new legal specifications are necessary," explains the responsible plant manager of HOCHDORF Swiss Nutrition AG. "It is therefore essential to perfectly coordinate the individual components in our plant to meet the highest purity standards and to guarantee consistent product quality. For this reason, LEWA's references for similarly hygienically demanding applications were important in the decision-making process for the membrane pump technology." This is especially true in the production of special milk powders for infants and toddlers. During the production of these products, the whole milk, which is about 87 percent water, is removed. In the first step, under product-friendly vacuum conditions, a milk concentrate is produced, which is very critical in terms of hygiene. The finished, concentrated semi-finished product is then transported to a cleanroom for further processing, where the final drying takes place. Until now, a piston pump was used for this important step, but due to its design and operation, it was not optimal for this application. "Since the pistons of the pump had to be cooled with water, there was a high risk of recontamination of the finished product, which, in case of contamination, cannot be sold and must be disposed of. For this reason, we were looking for a solution that does not require piston lubrication," continues the plant manager.

The choice fell on a Triplex G3F process membrane pump from the experienced pump manufacturer LEWA. With its Triplex units, the company offers a pump series specifically designed for the high pressures and flow rates of the food and fat processing sectors, so the required throughput of 4,000 l/h at 250 bar posed no problem. Additionally, the G3F features three specially selected M9 pump heads for aseptic applications at HOCHDORF. These are characterized by their PTFE sandwich membranes, which guarantee high operational safety with relatively low maintenance effort. The pump's hermetic sealing, combined with its system integration, ensures sterile conveying of the product. All fluid-contacting surfaces are made of high-strength DIN 1.4571 stainless steel and are finished to a surface roughness of Ra < 0.5 µm in accordance with hygiene requirements. "Both the suction and discharge sides are equipped with manifold piping, which was fitted with a pressure transmitter upon customer request in aseptic design," explains Pietro Pettoruto, Vice Director at LEWA Switzerland. "Both the manifold and flanges were finished with a surface roughness of Ra < 0.8 µm for better cleanability. This ensures the highest operational safety in accordance with the desired hygienic design standards."

Triplex drive as a guarantee of high performance

"The basis of LEWA's Triplex series is the special drive: thanks to its robustness, it is suitable for various areas in process and food industries," says Pettoruto. "The Triplex pump is designed for continuous operation to ensure long-term, interruption-free, and trouble-free operation." The drive housing is a single piece with a vertically flange-mounted motor. This design allows the necessary components such as bearings and seals to be minimized. The result is a compact and space-saving design that makes efficient use of the available space in the plant.

"The pump is used immediately after the heating and homogenization process of the product fluid," explains Pettoruto. "The product is then conveyed by the process membrane pump to the spray tower, where the final infant or follow-on milk powder is formulated. Besides meeting hygiene requirements, another challenge for the LEWA team was to adapt the necessary cleaning cycles (CIP/SIP) to the new G3F pump – all while strictly adhering to a very tight schedule. The staff responsible for the trouble-free operation of the unit since installation also had to be trained accordingly and prepared for future maintenance and servicing tasks." HOCHDORF is satisfied: "Although the highest hygiene standards and time pressure were required, the cooperation of all involved in the project was smooth." The system was commissioned after project completion in April 2017 and has been running very satisfactorily ever since. The risk of recontamination has also been significantly reduced.