Pumping up cheddar production

Glanbia Nutritionals is the largest manufacturer of milk products in Ireland. A fully automated cheddaring plant with seven cheese towers was installed at the company’s Ballyragget production facility in 2011.

After pasteurisation and the addition of rennet, the curd is cheddared by passing through a sealed system, which separates the whey and adds salt to the remaining curd. The resulting ‘prepared curd’ is transported by vacuum conveying lines to the cheese towers, where it is shaped into blocks.

Previously, conventional rotary lobe vacuum pumps were used to transport the curd and compress it into blocks. This vacuum system had the disadvantage that it could only pump down to 500 mbar. The pumps were equipped with frequency-controlled motors, but the vacuum level could not be improved by increasing the speed due to technical limitations. The installation used a total of nine of these pumps, each requiring 15 kW.

The decision was taken to replace the existing pumps with Busch Mink claw vacuum pumps.

Depending on size, Mink claw vacuum pumps reach a vacuum of between 100 and 200 mbar, which is significantly higher than the level achieved by rotary lobe vacuum pumps. The average working vacuum at the Glanbia site is between 300 and 350 mbar, giving Mink claw vacuum pumps ample reserve to cover demand spikes. 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 controlled precisely, maintaining constant curd density and thus improving product quality. Consistent product quality has also helped precision at the packing station, as the variation in cheese block weights has reduced.

Mink claw vacuum pumps also consume less power: the new pumps require only 9 kW each running at 50 Hz. Glanbia has calculated the annual savings in power costs to total €27,557.

Since the installation of the vacuum pumps in January 2014, no service interruptions or technical problems have been observed. This is partly attributed to the dry and contact-free working principle of the claw vacuum pumps, as they require no working fluids for compression, and the internal moving parts do not make contact with each other. In addition, the noise level is considerably lower than with the previously installed pumps