Vacuum dryer for extrusion and injection lines

A new vacuum granulate dryer opens up even more possibilities for specialists in the field of extrusion and injection molding of plastics. It allows the advantages of vacuum dryers to be used compared to conventional molecular filters-desiccants, namely: considerably lower operating costs, higher efficiency and improved control of the drying process. The throughput of the VBD ™ 300 vacuum dryer from Maguire Products, Inc. Achieves 136 kg / h, which is twice the performance of the model VBD 150 of the same manufacturer.

If the VBD 150 is designed for most injection molding machines and small extrusion lines in the manufacture of products such as medical tubing, the VBD300 allows you to take advantage of the vacuum dryer for a wider range of applications. For a mass production, Maguire also offers the VBD 1000 model. Compared to a molecular filter dryer, the VBD vacuum dryer consumes 60% less energy, but it dries granules six times faster and at the same time significantly reduces the thermal load on the polymer.

The speed with which the VBD system removes moisture allows the use of plastic for production within 35 minutes after a cold start. Like the other VBD models, the VBD 300 dryer is a gravimetric system that accurately monitors the weight of the material by means of strain gauges at two critical points, allowing you to accurately monitor the flow of material and strictly document the process parameters when it needs to be certified by the customer. According to Frank Kavanagh, vice president of supply and marketing at Maguire Products, strain gauges can also better control the drying process.

Thanks to the use of strain gauges, drying speed can be precisely adapted to the capacity of the injection molding machine or extruder, which is especially important for efficient drying of technical polymers, for example polyamide. Since thanks to strain gages at the end of the production cycle there is no material in the dryer, it is possible to proceed immediately to the next stage of production. Due to the gravity, the material passes through three vertically arranged drying levels, with the material moving from one level to the next being controlled by high-speed slide gates with an accuracy of ± 4 g per dosage.

The tanks for the three phases of this process are installed on top of each other: from above is a heating hopper in which the granulate is heated to a predetermined temperature; in the middle - a vacuum chamber in which vacuum reduces the boiling point of water, as a result of which the moisture contained in the granulate evaporates and is displaced from the granulate into the low pressure environment; below is a pressurized storage / unloading hopper, which is constantly blown through with a membrane air dryer to maintain a predetermined moisture level until the material is unloaded.

The vacuum chamber and the storage bin are mounted on strain gauges. The VBD 300 dryer is equipped with an intuitive, easy-to-maintain touch screen control panel that allows the operator to control all drying parameters with just one monitor.

Maguire Products, Inc