COBRA Dry Screw Vacuum Technology for Manufacturing High Quality Rubber Medical Device Components

Montegaldella, Italy Datwyler Pharma Packaging Italy Srl. manufactures rubber components for medical equipment. Vacuum is necessary for the process in order to exclude air bubbles from the finished component and to remove vapour generated by high temperature and pressure. The moulding machines were originally equipped with oil-lubricated rotary vane vacuum pumps. However, this resulted in a reaction between oil in the vacuum pump and process vapour, causing emulsions and greasy deposits to accumulate in the vacuum pumps. Datwyler’s thermoforming machines now rely on dry screw vacuum technology by Busch, solving the problem of a reaction with operating fluids.
Blood collection tubes

The output of the company's production facility in Montegaldella (VI) is primarily for syringe plungers and sealing caps used in sterile products. The first production stage is the mixing of rubber with additives and chemicals to form strips of base material, which are then coiled. The composition of this base material is dependent on its later application, and is prepared to customer specifications. Two production lines of twelve thermoforming machines each cut the base material strips to size automatically. The trimmed sections are then pressed into a mould under vacuum, after which the individual components are stamped, vulcanised, tested, washed and packed.

The problem was as follows. The moulding process takes place under high mechanical pressure, at temperatures between 175°C and 180°C, and in a vacuum of 1 mbar (-999 mbar). This vacuum level is necessary to exclude air bubbles from the finished component, and to remove vapour generated by the high temperature and pressure of the process. The moulding machines were originally equipped with oil-lubricated rotary vane vacuum pumps, which soon developed a serious problem: the vacuum pump oil reacted with the process vapour, causing emulsions and greasy deposits to accumulate in the vacuum pumps. These deposits reduced the vacuum output, so the required level and pumping speed could no longer be achieved. Costly measures to keep these vacuum pumps running were attempted, including changing the oil every two weeks. In 2009 Datwyler signed a maintenance agreement with Busch, in which Busch agreed to carry out third-party servicing of the vacuum equipment.

After Busch vacuum specialists had studied the problem in depth, they presented their recommendations to Alessandro Piccoli, Maintenance Manager at the Montegaldella (VI) site. Their solution: replace the oil-lubricated rotary vane vacuum pumps with Busch dry screw technology.

Consequently, a COBRA screw vacuum pump was subjected to extensive testing. These vacuum pumps operate without compression chamber fluids, which means there is no contact between the extracted vapour and any other medium in the vacuum pump. In addition, COBRA vacuum pumps run at a working temperature which allows vapour to pass through the pump without condensing. The COBRA test system proved to be highly satisfactory, so Alessandro Piccoli ordered two COBRA vacuum pumps to supply a line of six moulding machines. Both vacuum pumps incorporated Panda Roots vacuum pumps as boosters. This arrangement permitted the vacuum system to be installed away from the production buildings, with vacuum for the thermoforming machines supplied by a pipework system. An upstream vacuum reservoir ensures that the required vacuum level and pumping speed are constantly available. In 2012 two additional vacuum units were ordered and installed – also with COBRA fore pumps and Panda Roots booster pumps – to supply a complete line of twelve thermoforming machines. All the vacuum units are equipped with a fully automatic control system, which monitors the vacuum level and activates the minimum number of vacuum pumps required to meet the current demand from the twelve thermoforming machines. This means that all the vacuum pumps run only when the entire line is operating at maximum capacity. In everyday use, only three COBRA/Panda combinations are required.

For Alessandro Piccoli, whose goal is maximum energy efficiency, this is another important argument in favour of COBRA dry screw technology and the centralisation of the vacuum supply. Plans to extend the vacuum system to supply all 24 moulding machines have been made, and will be implemented shortly.

The Busch solution has brought the following advantages, says Maintenance Manager Alessandro Piccoli, :

  • No reaction between extracted vapour and operating fluids, due to dry screw vacuum technology
  • No accumulation of condensates in the vacuum pumps, due to the even temperature distribution throughout COBRA units
  • Considerable energy savings, due to vacuum supply centralisation and automatic demand-driven control
  • An extremely reliable vacuum supply
  • Significantly reduced maintenance effort and consequently lower costs for servicing, replacement parts and production downtime
  • Easy access to the vacuum system even if thermoforming machines are operating, maintenance possible during production
  • No noise emissions in the production building or at workstations, due to external location of centralised vacuum system


About Datwyler Pharma Packaging Italy Srl.
Datwyler Pharma Packaging Italy Srl. is part of the international Datwyler Sealing Solution Group, which is owned by the Datwyler corporation. Datwyler Pharma Packaging Italy Srl. operates two production sites in Italy. At the Montegaldella (VI) facility, components such as stoppers for blood collection tubes and parts for single-use syringes are manufactured. The site employs 140 staff and operates around the clock in a 3-shift system. The manufacturing process includes all stages of production, from mixing of raw materials to preparing the finished sterile rubber components for shipment. Datwyler's customers are medical technology companies throughout the world.


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