When to use Loss-in-Weight Batching

Loss-in-Weight batching provides the fastest and most accurate measurement and control of individual ingredients fed into a batch process

When a process requires that each ingredient be weighed more accurately, or when batch cycle times must be kept to the minimum, or there is a large disparity in the ratio of major ingredient to minor ingredients, Loss-in-Weight (LIW) batch feeding is the optimum solution.

Batch size and accuracy requirements will often determine whether Gain-in-Weight or Loss-in-Weight batching is best to for your process. In general, Gain-in-Weight can be used when the response time and resolution of a platform scale is sufficient to guarantee batch accuracy requirements. But most floor scales do not have sufficient speed and resolution to batch small amounts of products into a large volume container.

Where Gain-in-Weight batches employ volumetric feeders to feed each ingredient sequentially, Loss-in-Weight feeders operating in batch mode feed multiple ingredients simultaneously into a collection hopper.

To achieve an accuracy of +/- 0.1 to 0.5%, Coperion K-Tron’s Loss-in-Weight Batching systems employ a hopper with Coperion K-Tron Loss-in-Weight feeders mounted on high-speed digital load cells that provide 1 part in 4 million resolution.

A Loss-in-Weight batch controller monitors material weight loss from the hopper and controls the start/stop functions of the feeder.

With each feeder possessing its own dedicated weighing system, the LIW batching system delivers each ingredient with greater accuracy and in less time.

Unlike the layering of ingredients that you get with Gain-in-Weight batching, in Loss-in-Weight batching all the ingredients are metered at the same time, eliminating the layering effect and the time and cost for further processing downstream.

Loss-in-Weight batch feeding is the optimum solution when a recipe calls for micro ingredients. These minor ingredients frequently require highly accurate weighing to remain within spec of the recipe, and they are usually expensive, making cost control a high priority.

If additional security or verification of delivered batch weight is required, a dual weighing scenario may be used.

This concept employs a combination of the Loss-in-Weight Batching system feeding into a Gain-in-Weight system.

The Gain-in-Weight system is simply used to confirm the batch delivered by the Loss-in-Weight system prior to acceptance of the batch and further processing.

In the above illustration of a pharmaceutical dispensary application, Loss-in-Weight feeders are shown feeding various components to an IBC on a platform scale.