Mass Coriolis flowmeters in color dosing

At Lano Carpets in Harelbeke, Belgium, an inline mixer produces any color with the help of Coriolis mass flowmeters. The company produces 23,920 square yards of tufted carpet every day. After producing its carpet dyes in batches for years, a complex and costly process, the company set out to find an alternative that would simplify and improve this process. To increase the flexibility of its machines, avoid time loss, and reduce product waste and costs associated with traditional batch manufacturing, the company decided to stop manufacturing its dyes in batches and switch to a continuous process using an inline mixer that produces the right color instantly by injecting coloring agents into a collector containing a premix.

Technical challenge

Obtaining precise color shades and avoiding discrepancies require a highly stable process and accurate dosing of the coloring agents in the right proportions, taking into account the premix flow rate. This control requires precision flow rate measurement for the premix and the coloring agents as well as constant pressure inside the collector. Lano found a solution in a system that was designed and created in conjunction with engineering company ProcAT, which uses highly accurate process management to continuously produce precise color shades every time.

Conceptual solution

At Lano, an inline mixer system was added that can handle any color with the help of a SITRANS FC410 Coriolis flowmeter from Siemens. Using the flowmeters, the coloring agents required to manufacture a specific color shade are injected into the inline mixer in proportions that stringently adhere to the settings. However, when the machine changes from one product to the next, a new color is mixed automatically, creating minimal waste and a faster process.

The volumes of coloring agents pumped into the machine are measured using the Coriolis flowmeters, while the application is controlled and supervised through a supervisory control and data acquisition (SCADA) and human machine interface (HMI) system, which manages the recipes sent by the enterprise resource planning software and translates them into precise dosages of coloring agents according to the desired color shade. A large quantity of premix is prepared with all the ingredients of the dye, apart from the coloring agents, which are processed in separate batches of three colors: yellow, red and blue. Two different concentrations are created to obtain a wider range of colors in the dosage process.

The coloring agents circulate continuously around the machine and are injected into the collector through a valve. Frequency-controlled pumps ensure the correct proportions are used, while the Coriolis flowmeters transmit the required feedback to the pump control system. Turbulence inside the collector ensures good mixing so the dyeing of the carpet is homogeneous.

Technical benefits of the Coriolis flowmeter system

In Lano’s new carpet dyeing system, the Coriolis flowmeters provide maximum precision for the pump-control system, which plays a pivotal role in the mixing ratio. The flowmeters measure the flow rate and density and convert them into a volumetric flow rate (the quantity that determines the mixing ratio).