The key difference between gravimetric and volumetric feeder is that we measure the rate of a gravimetric feeder in the unit of volume per unit time whereas we measure the rate of a volumetric feeder in the unit of weight per unit time.

Feeders are useful to handle bulk solids. There are two forms of feeders and we call them as gravimetric feeders and volumetric feeders. A gravimetric feeder consists of a volumetric feeder associated with a weighing system. It measures and controls the discharge of a substance at a constant weight per unit time. A volumetric feeder, on the other hand, is a screw conveyor that runs at a constant speed, discharging the substance at a constant volume per unit time.

CONTENTS

1. Overview and Key Difference
2. What is Gravimetric Feeder
3. What is Volumetric Feeder
4. Side by Side Comparison – Gravimetric vs Volumetric Feeder in Tabular Form
5. Summary

What is Gravimetric Feeder?

Gravimetric feeder is an instrument that is important to control and measure the speed of a substance in an instrument system. This equipment can handle the bulk solids. It allows the solid to discharge at a constant weight per unit time.

The unit of measurement is kg/min. The signal about the weight is used as a system of feedback control. It controls and monitors the feed rate that enters a particular instrument. The weighing systems include several examples such as platform scales, load-cells, weigh hoppers, etc. Depending on the overall process, the gravimetric feeder may be a loss-in-weight system or a gain-in-weight system.

What is Volumetric Feeder?

Volumetric feeder is an instruments that is important to control and measure the rate of a substance entering into a system. It measures the solid discharge rate at a constant volume per unit time. The unit of measurement is L/min. A volumetric feeder is usually a screw conveyor that runs at a constant speed.

Figure 01: A Volumetric Feeder

This equipment includes several components such as vibrating systems, agitation, massaging, etc. to ensure the uniformity of the feed and the constant rate of the feed flow. This system is important when we cannot establish a gravimetric feeder.

What is the Difference Between Gravimetric and Volumetric Feeder?

Volumetric feeders are instruments that are important in controlling and measuring the rate of a substance entering into a system. They contains a screw conveyor that runs at a constant speed. Whereas, Gravimetric feeders are instruments that are important in controlling and measuring the speed of a substance in an instrument system. They consist of a volumetric feeder associated with a weighing system such as platform scales, load-cells, weighs hoppers, etc. Moreover, the volumetric feeders measure the solid discharges at a constant weight per unit time whereas, the gravimetric feeder measures the solid discharge rate at a constant volume per unit time. This is the main difference between gravimetric and volumetric feeder.

Summary – Gravimetric vs Volumetric Feede

Feeders are equipment that are important in handling solid bulks. They are useful to enter s solid into a processing system at a required rate. There are two forms of feeders; gravimetric feeders and volumetric feeders. The difference between gravimetric and volumetric feeder is that we measure the rate of a gravimetric feeder in the unit of volume per unit time whereas we measure the rate of a volumetric feeder in the unit of weight per unit time.

Reference:

1. “Basics of Gravimetric and Volumetric Feeding.” Plastics Technology, Plastics Technology. Available here   

Image Courtesy:

1.’Tangentialschleuse edelstahl’ (CC BY-SA 3.0) via Commons Wikimedia  

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