Glanbia Nutritionals in Ireland operates one of the world’s most modern production facilities, manufacturing high-quality, matured cheddar cheese. Glanbia Nutritionals is part of the Glanbia Group, Ireland’s largest manufacturer of milk products and a global supplier to producers of foodstuffs and baby food.
At the Ballyragget production facility, curds undergo a process known as “cheddaring.” After pasteurization and the addition of rennet, the curd runs through a sealed system that separates the whey and adds salt to the remaining curd.
In 2011, seven cheese towers were installed in the fully automated cheddaring plant. Vacuum conveying lines transport the curd and residual milk from the plant to the cheese towers. An air current carries the curd to the top of a 10m-tall cheese tower, into which it is dropped.
The curd mass is compressed by its own weight, forming a column in the tower. A vacuum is maintained to remove residual milk and air that may have been included in the compression process. The cheese is cut into 20kg blocks, packed and weighed in a block chamber at the base of the tower.
In the originally installed vacuum system, conventional rotary lobe vacuum pumps were used to transport the curd and compress it into blocks. However, this system could only pump down to 500 mbar (375 torr). Additionally, the pumps were equipped with frequency controlled motors, and the vacuum level could not be improved by increasing the speed due to technical limitations. The system used a total of nine pumps, each requiring 15kW of electricity.
Over a year ago, Glanbia Plant Operations Manager Vincent Cleere replaced this system with Busch Mink claw vacuum pumps, which reach a vacuum down to 200 mbar (150 torr). The pump motors have individual frequency control, enabling the vacuum level to be adjusted to suit the process. The vacuum in the cheese towers is precisely controlled to maintain constant curd density, improving product quality and packaging consistency by reducing block weight variation. The new pumps also consume less power than the rotary lobe vacuum pumps, with each requiring only 9kW of electricity while running at 50Hz.
“The Mink claw vacuum pumps have reduced our energy requirements for vacuum generation by 54kW per hour,” says Cleere. Because the plant operates 18 hours per day, seven days a week and 45 weeks a year, the energy cost savings alone pay for the investment.
Since the installation of the Mink claw vacuum pumps, the plant has not experienced any service interruptions or technical problems. In addition, Cleere says the maintenance requirements are minimal, with the filters requiring cleaning just once a week. Adhering to the Busch recommendation of a gear oil change every 20,000 operating hours, the Glanbia site will be serviced roughly every five years.
The pumps work under a dry and contact-free principle, requiring no fluids for compression and keeping the internal moving parts away from each other.