Basic Components of a Flexible PU Foam Production Line:Raw Material Storage and Preparation System

A polyurethane flexible foam production line generally consists of several fundamental units, including raw material storage, conveying and metering systems, mixing and blending systems, block molding (including molds, liner paper, and liner film) systems, control systems, ventilation systems, cutting machinery, and block transportation and storage systems. In continuous production lines, auxiliary units such as a radiation-based foam density measurement system, block trimming machinery, block weighing systems, and a flat-top device may also be included.

First, let’s introduce the raw material storage and preparation system.

Raw material storage tanks are typically reactors or storage tanks equipped with stirrers and constant temperature control systems using jackets or coil heating. These tanks are usually made of stainless steel or carbon steel with surface treatments like metal or plastic coatings, chemical plating, or corrosion-resistant coatings of stainless steel, nickel, chromium, or plastic. These treatments help prevent both corrosion of the tanks and contamination or deterioration of materials.

For high-pressure foaming machines, the material tanks need to be pressure vessels capable of withstanding 0.4–0.6 MPa. The tanks are filled with dry air or nitrogen to prevent moisture absorption or oxidation of the materials. The stirring and temperature control systems help maintain uniform material consistency and temperature, ensuring a stable foaming process. The image below shows a typical storage tank.

The two main raw materials in production are polyols and isocyanates, which can be transported in barrels or specialized tank trucks. During transportation, dry air or nitrogen must be maintained inside the tank truck to prevent moisture absorption. If vent pipes are used, silica gel dryers or refrigerated dryers should be installed. Additionally, the temperature of the raw materials must be kept within the required range to prevent crystallization or degradation, ensuring material quality.