Gravimetric loss-in-weight Feeder

PETROSADID is one of the paramount company engaged in providing a various types of Volumetric and Gravimetric feeders which are utilized in wide range of industries.

What follows gives you a brief introduction that covers the definition and application of these feeders:

Feeders are often classified by the metering device employed to discharge material into the process. Each feeding device is engineered to handle specific types of materials and the challenges they present. Most of these material delivery methods may be configured for use in volumetric or gravimetric modes.

Your feeder selection, and the success of your application, will be greatly influenced by the specific characteristics of the materials you must feed, the recipe precision needed for your process and the throughput required.

PETROSADID Company, backed by rich industrial experiences, is able to provide you with the best solution.

A loss in weight feeder is a gravimetric metering device that receives material from an upstream supply and accurately doses the material into a process at a pre-determined federate, typically through a screw (anger or helix), twin screw, or vibratory tray.

True to its "loss in weigh" name, this feeder's operation is regulated by the amount of live load that is lost as product is discharged. In order to do this efficiency, the loss in weight feeder receives constant feedback from a sensitive weighing device, which ensures that the precise amount of material is delivered either continuously or in each batch.

The general principle of operation is as follows:

• The loss-in-weight hopper is rapidly filled via an automatic filling valve. At a hopper-full weight, pre-set within the microprocessor, the filling valve will close.

• The metering feeder starts (or is already running from the last cycle) and feeds product into the process; thus the weight in its product hopper gradually falls.

• The falling weight is measured every few milli-seconds and this information is averaged and stored by the microprocessor as a falling weight per unit time (Kg per min). This weight per unit time is compared to a weight per unit time already pre-set by the operator via the microprocessor key pad and stored in memory.

• Any difference in the characteristic slope of the falling weight per unit time and the slope of the pre-set weight against time, is fed to a process controller and used to speed up or slow down the product feeder in order to make the two slopes identical.

• At a pre-set hopper low weight, the metering feeder will be locked onto its last averaged filling valve again signaled to open, so rapidly filling the hopper.

• When the hopper is again filled, the metering feeder will be brought back onto automatic control at the original correct speed that was memorized by the microprocessor during the previous cycle.

• Thus the cycle will repeat, with the microprocessor going through a continuous learning curve which will get more accurate with each cycle

BATCH WEIGHING

Standard loss-in-weight modules can be supplied eradicating weigh hoppers and in-flight material. This system is particularly useful when the product to be weighed is sticky and does not have good flow properties.

We can provide batch weigh hoppers and dischargers for every application from a few kgs to tons. Our product handling experience is vast covering products such as additive powders which occasionally used for some grades of PP, Ammonium sulfate, Sodium Cyanide, Ester Acrylates, Super Absorbing Polymers, Fumaric acid, Sodium formate, Urea, Heavy aromatics, PVC/ MAH/ PBT/ SBS/ SB/ EPS and also Food additives, food colorants and spices, which are used in food industry.