Blending

Digital In-Line Blending is a method of standardizing products or blending products together by introducing multiple streams of flow or components into a common pipe or small vessel.

Digital blending can be thought of as continuous standardization of product. Digital In-Line Blending is similar to batching in that ingredients and additives are metered together into a tank or pipe. However, it differs in that all the ingredients are metered simultaneously at accurately controlled rates using digital technology to assure that the product batch is within specification at all times. Digital In-Line Blending could refer to a continuous stream of small batches, those being whatever mixing residence time the process piping affords. One might say that a batch size, in Digital In-Line Blending, is determined only by the amount of mixing volume or residence time required prior to downstream operations or filling. Therefore, Digital In-Line Blending size may be as small as ounces in the head of a pump, or as large as gallons in a small batch tank or balance tank prior to downstream processing. There are a number of factors which dictate how small a batch can be. For example, if minimal agitation is required to standardize the product and if the product is not sensitive to In-Line mixing, then the product can be standardized or digitally blended together into a common piece of pipe or into the suction of a pump or through an In-Line static mixer. On the other hand, if the product requires additional mixing, such as emulsions, or requires some specific chemical reaction, then a vessel or tank will be required. It is possible that Digital In-Line Blending may use a small balance tank or vessel to achieve the proper agitation or mixing prior to further downstream processing.

The technique of continuous In-Line blending for product standardization is not a simple flow rate control scheme. It is a completely engineered, synchronized, accurate system. It utilizes a variety of meters specifically selected for each ingredient's unique physical characteristic. Typically a meter will generate a pulse for a specific unit volume. An example would be a component flowing at 50 gallons/min through a magnetic flow meter, which is equipped with a 2KHZ pulse output calibrated for 100 GPM full flow. This would be generating 1200 pulses per gallon. That is, we would be able to meter to better than 1000 parts of a gallon. By forcing the control system to maintain a plus or minus output accuracy of 1 pulse, this stream would be controlled to better than 1/1000 of a gallon.

Continuous digital blending technique does exactly that. It forces all the metered flows to respond to errors of plus or minus 1 pulse as metered. The overall system is synchronized by having a common demand for product total ratioed by each stream. This demand is then paced back by any stream which cannot keep up until the total product demand is low enough that the pacing stream can keep up. This means that the total product rate will never exceed the slowest ingredient's ability to deliver. The end result is that the total product, or blend, is optimized and balanced for ingredients and rate of production.

Digital In-Line Blending technique also provides for standardizing of product by component, in other words, accurate material balance.