The gravimetric doser and the volumetric doser are devices used in the industrial sector for the precise measurement and dosing of powders or granules. 

The two tools differ significantly in their measuring methods and in  their possible applications. We are going to talk about it in this article, also presenting the solutions proposed by Vismec for gravimetric and volumetric dosing.

Gravimetric doser and volumetric doser

So let’s start by trying to understand what the two devices are and presenting the differences between the gravimetric and volumetric dosers.

In the dosing process, the gravimetric doser measures the quantity of material by weight, thanks to an integrated scale that continuously measures the weight of the material. 

Consequently:

• doser weighs the material in real time and in a highly accurate way;
• device compensates for any variations in the density of the weighted material or environmental conditions;
• this precision is crucial in sectors such as the chemical, pharmaceutical and food industries, where the correct dosing of ingredients is essential for the quality of the final product.

Even in applications in the plastics processing sector which requires a high precision, the gravimetric blender ensures quality results. An example? The dosing of additives.

Instead, the volumetric dosing unit doses the material based on the occupied volume. This type of doser often uses a system of measuring chambers or tanks that fill and empty cyclically, dispensing a pre-established amount of material. 

Volumetric dosers are often faster than gravimetric dosers, but can be less accurate because they do not take into account variations in material density. As we will see in the next paragraph, the volumetric dosers that our company offers, on the other hand, allow the dosing of plastic granules while maintaining precision. 

A further difference between the two dosing systems concerns the calibration of the instrument:

• the gravimetric doser requires accurate initial calibration to ensure the accuracy of results over time;
• in the case of the volumetric doser, adjustments must be more frequent because the density of the material may vary. 

Additionally, gravimetric blenders are more suitable for materials that may compact or have a significant change in density during production.  

Thus, the two types of blenders have different operating methods. Vismec offers advanced and effective solutions for gravimetric and volumetric dosing, calibrated according to: 

• type of application;
• supported plastic processing;
• characteristics of the use environment.

We will present them more thoroughly in the next paragraph.

 

Products offered by Vismec for volumetric and gravimetric dosing

As we were saying, Vismec volumetric and gravimetric dosers allow accurate dosing of plastic granules and any additives. Each product has its own specific features, designed to best meet the needs of customer companies.

• The MGF gravimetric doser accurately measures the quantity of blended additive with the plastic material. The dosing unit features a high-precision automatic recalibration system, without the need for additional configurations.
• The WSB series doser is equipped with advanced control technology that allows accurate and real-time monitored mixing of the granules. The device fits on any moulding machine, even allowing the loading time of the plastic material to be adjusted.  
• Vismec volumetric dosers are also designed to support plastic injection or extrusion moulding machinery. The device is designed to withstand mechanical stress and vibration without compromising the precision of operations. In addition, the loss-in-weight volumetric dosing system allows the weight of the polymers to be constantly monitored, ensuring the optimum quality of the end result.

All products offered by Vismec for gravimetric and volumetric dosing, in addition to precision, have a common ability to facilitate machine maintenance and cleaning. Furthermore, the integrated control devices optimise dosing operations and allow the customer company to reduce material waste and associated costs.

Would you like to learn more about the dosing systems and other products Vismec offers companies in the plastics sector for polymer dehumidification, conveying and storage operations? Contact our team and tell us what you need. Together we will find the most effective solution for your company.