Van Beek, Drunen, the Netherlands, has over the years manufactured hundreds of bespoke dosing screws for individual applications. From experience thus gained, it has now developed a standard model which – thanks to a choice of easily installed options – can be used in virtually any situation. For volumetric weighing, the number of revolutions determines the dosing. There are different options for calculating how many revolutions the screw must make. Van Beek measures how much product comes out of the screw per revolution and then it is clear how many revolutions are needed to achieve the required quantity. For sticky products such as flour, gravimetric weighing is preferable. A weigh belt, fed by the screw, then measures the weight of bulk product. The belt sends a signal to the screw as soon as the required weight is reached. A loss-in-weight alternative is also available.

 

For products with poor flow characteristics, there is the option of a fixed-speed, powered stirrer which ensures the screw is filled to the optimum – an important factor in the case of volumetric applications. Another option is a pneumatically operated refill valve. This shuts off the screw outlet as soon as the required weight is reached. There is also a twin dosing screw option (pictured). A large screw delivers the main mass, e.g. to 19.5kg and then stops. A smaller screw continues running and fills it to the required weight of 20kg.

 

A dosing screw can offer a solution for every conceivable process where controlled feed is necessary: for example, in wastewater treatment plants to add flocculant; in the food industry to add salt, sugar or herbs; and in brick factories to add colorant for bricks. www.van-beek.nl 

 

 

Van Beek standard dosing screw, showing twin screw option