Feature Food processing & packaging Putting ice-creams in their place
Pick and place problems encountered on Unilever’s Twister ice lolly production line have been solved by installing new grippers from Bosch Rexroth
T
wister ice creams are a summer favourite in the UK, so it’s not surprising that the production line at Unilever’s plant in Gloucestershire is one the busiest on the site. “We run at a rate of 450 ice creams per minute, 24 hours a day and 6½ days a week,” said engineering techni- cian Chris Burch. “It is the most booked and therefore the hardest work- ing line in our Gloucester facility.”
Ice-cream distribution Twister ice creams come out on plates from the freezers on a conveyor and a pneumatic hammer breaks them from the plate. At this point, a pick and place gripper comes across and dis- tributes the ice cream onto an eight lane conveyor system from where the product goes on to packing. However, there have been issues with the grippers, which pick and place the ice creams before packaging. They were creating problems within three weeks of installation with clear signs of wear. Also, the grippers were failing to properly hold onto the ice creams, and were letting them drop into the production floor.
“The issue we had was the reliabil- ity of the gripper cylinders which were supplied by a previous OEM,”
the job. Once calculations were com- pleted the decision was taken to trial two Bosch Rexroth GSP-A-25 grippers that only opened to the required 45˚. After several weeks in the field, an examination of the new grippers showed that there were no signs of wear at all. The decision was then taken to acquire eight sets of six grip- pers mounted on an angled mounting plate similar to that which was cur- rently in use, along with manifolds for the pipe work.
said Burch. “We were finding that each cylinder only had a working life of approximately 3-4 weeks and were very costly to replace.”
Unilever estimates that the annual cost for the replacement of the 180 cylinders on the Twister production line was in the region of £16,000, before labour costs were factored in.
Alternative grippers
The decision was therefore taken to look at alternative suppliers of gripper technology.
“The gripper that had been specified was totally wrong for the job,” said Steve Morris, an expert in pick and place technology for food applications at Bosch Rexroth. “The Twister line was equipped with a 180˚ gripper from open to close which was at least two sizes beyond what was needed.” Bosch Rexroth worked with Unilever to complete an accurate sizing calculation to ensure that any new gripper specified was suitable for
Bosch Rexroth offered Unilever a total solution to its gripper problem, ensuring any future maintenance would be quick and easy
Quick replacement “We provided the grippers, fingers and plate in order to offer Unilever a total solution to the gripper problem, which would ensure that with any future maintenance a complete head could be replaced which would offer very fast changeovers and minimal downtime,” said Morris. “Now, with 2-3 bolts to put in a new gripper, the line can be up and running again.”
“Bosch Rexroth supplied a bespoke solution to our problems,” said Burch. “What impressed me was that they continued to work with us to find the best solution.”
The total outlay for the Bosch
Rexroth Twister solution was approxi- mately £14,000, but Unilever were unphased by the investment. “To be honest the cost of the solution was swallowed by the replacement and downtime costs associated with the previous grippers,” said Burch. “We now have a much more efficient solu- tion which can be maintained much more easily and cost effectively.”
Bosch Rexroth T: 01285 863000
www.boschrexroth.co.uk Compressors recover energy to keep heating costs down
hropshire-based Müller Dairy has made savings in gas process heating costs by using Atlas Copco compressors which incorporate energy recovery technology. Compressed air plays an essential role at the Müller Dairy manufacturing plant at Market Drayton, where over 600,000 litres of raw milk are processed daily. This is particularly true in the company’s yogurt and fruit process operations, where compressed air is used in supplying air cylinders, filling machine and process valves, as well as providing a sterile air barrier for end products. The compressed air installation comprises a purpose-built ZR315VSDFF oil-free compressor together with two fixed-speed, water cooled ZR200s. The heat recovery capability of the ZR200s is utilised in the form of recovered hot water. Working in conjunction with ammonia compressors and the yogurt and fruit processes, this hot water is used to pre-heat yogurt bases, which eliminates the need to generate steam and the running costs of two gas-fired boilers that used to be incurred in the process. Compressed air users who, like Müller Dairy, integrate the flow of hot water into their plant processes are
S
able to recover 90-95% of a compressor’s electrical energy input as hot water using the ZR series of water-cooled, oil-free, 55-750 kW compressors. Because of the vital requirement within Müller’s production operations for pure, uncontaminated process air that comes in contact with the finished products, guaranteed 100% oil-free air was a mandatory feature of the installation. This requirement has been assured with the installation of Atlas Copco compressors that have been tested Class Zero and certified by TÜV according to the ISO 8573-1- Class 0 standard. This helps Müller ensure the quality of its consumer products and its reputation. Atlas Copco
T: 0800 181085 Process & Control SEPTEMBER 2012
www.atlascopco.co.uk Enter 225 23 Enter 224
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36