The Mondelez coffee production plant in Berlin has been in operation since 1981. The brands Jacobs, Onko and Hag are produced in Berlin, with Jacobs Krönung – also known as Jacobs Monarch – accounting for a majority of the overall production. The coffee is packaged on multiple packaging lines, all fitted with rotors into which the bags containing the coffee are automatically fed and sealed. The air in each item of packaging is extracted under the vacuum bell jar through a tiny opening in the bag, after which the packaging is sealed such that it is completely airtight. These packaging machines were each originally fitted with two to four rotary vane vacuum pumps for the purpose of generating the packaging vacuum.
Service Manager Renald Lange was looking for a more cost-effective solution for vacuum generation so the number of rotary vane vacuum pumps could potentially be reduced from a total of 28. Renald Lange sought the advice of Busch's project engineers, with the result being a centralized vacuum supply to which the eleven packaging lines are connected. Ten of these eleven packaging lines are permanently in operation, with one packaging line being operated in standby mode.
The central vacuum system that was specially designed for Mondelez has been in operation since summer 2010 and has since been running in a three-shift operation, six days a week, 24 hours a day. The system consists of ten vacuum pumps, with two additional vacuum pumps running in standby mode in a back-up pumping station. The control of the vacuum supply ensures a permanent and constant vacuum in the pipeline system.
The main reason for the centralization of the vacuum supply was the energy savings. With the reduction in the number of vacuum pumps from 28 to only ten, it was possible to reduce the installed power by 150 kW. The demand-based control helps achieve additional energy savings, as it controls the operation of the individual vacuum pumps according to the vacuum performance currently required at the individual packaging lines. "We do not foresee all of our vacuum pumps being operated at full load at the same time," states Mr. Lange, noting the experiences of the first three years of operation. By dividing the vacuum supply into two vacuum circuits for rough and medium vacuum, it is possible to deploy Panda rotary lobe vacuum boosters to further increase the pumping speed. In addition to the high pumping speed, the advantage of these vacuum pumps is that they can be operated with a relatively low level of motor power.
Mr. Lange sees a further benefit to the central vacuum system since it is set up outside of the production and packaging rooms. This means that system maintenance can be performed while the system is in operation, as maintenance personnel have no need to enter the production and packaging rooms. This is achieved through the use of two vacuum pumps from a back-up pumping station that are operated in standby mode. The back-up pumping station is generally only enabled during maintenance work, when other vacuum pumps are disconnected so that maintenance can be performed on them. In the case of the previous decentralized vacuum supply, in-house maintenance personnel performed maintenance on the rotary vane vacuum pumps every 3,000 operating hours. This was only possible when the packaging lines in question were subject to a shutdown period. Mondelez also has a maintenance contract with Busch. This stipulates that a Busch technician will perform an oil change on the individual vacuum pumps every six months and that maintenance including a filter change will be performed on an annual basis. Busch also guarantees that a replacement model will be available in the event of vacuum pump failure. "However, to date, we have not experienced a malfunction of any kind in the vacuum supply" says Mr. Lange. A preventive analysis of used oil demonstrated that the level of thermal stress to which it had been subjected was considerably lower than had been assumed, leading us to consider extending the oil change intervals. As a result of the energy savings and the maintenance work performed by Busch, the operating costs of the vacuum supply were reduced considerably in the first year of operation. The objective of minimizing costs in the vacuum supply has therefore been fully met.