There are two methods to eliminate foam: mechanical defoaming and chemical defoaming. Mechanical defoaming refers to breaking the foam with mechanical force or breaking the foam with pressure. This method does not require the addition of other substances, saves raw materials, and reduces the chance of contamination of chemical reagents. However, this method requires certain equipment and power, and cannot fundamentally eliminate the factors that cause foam. Chemical defoaming is to add defoaming agents. Compared with mechanical defoaming, this method saves time and effort, has a small investment, and is effective quickly.