In the food processing industry, EPDM or polytetrafluoroethylene gaskets are more preferred.
1. EPDM
High sanitation and safety
EPDM itself is non-toxic and meets the strict requirements of the food processing industry for sanitation and safety. In the process of contact with food, no substances harmful to the human body are released, which can ensure the quality and safety of food.
Good chemical resistance
During the food processing process, some acidic (such as citric acid) or alkaline (such as lye for food processing) substances may be exposed. EPDM can withstand a certain degree of chemical corrosion and will not be quickly damaged due to contact with these chemicals, thereby ensuring the sealing performance of the plate heat exchanger.
Wide temperature adaptability
The temperature range of the heat exchange process in the food processing industry is generally not as extreme as some industrial chemical processes. The temperature resistance range of EPDM is usually between -40℃ and 150℃, which can meet the temperature requirements of most food processing, such as food pasteurization (generally around 60-90℃), cooking (around 100-120℃) and other processes.
2. Polytetrafluoroethylene (PTFE)
Excellent chemical stability
PTFE is known as the "King of Plastics" and is almost not corroded by any chemical substances. In food processing, whether it is acidic juice, vinegar, or alkaline alkali solution, it can maintain stable chemical properties, ensure good sealing, and will not produce harmful substances due to chemical corrosion, thereby ensuring the purity of food.
Good high temperature resistance
PTFE can be used in a wide temperature range, and it can withstand temperatures from -196℃ to 260℃. In some high-temperature processing food industry scenarios, such as high-temperature sterilization (temperature can reach 120-135℃), it can also play a good sealing role and will not be deformed or damaged due to high temperature.
Non-stickiness
The surface of polytetrafluoroethylene is very smooth and non-sticky. During food processing, this feature can prevent food ingredients from sticking to the surface of the gasket, which is conducive to keeping the gasket clean and avoiding the growth of bacteria. It is also convenient for cleaning and maintenance of the heat exchanger, meeting the high standards of hygiene in the food processing industry.
Although nitrile rubber has good oil resistance and wear resistance, its temperature resistance is relatively limited, and its corrosion resistance in the environment of various chemical substances (especially acidic substances) that may be exposed in the food processing industry is not ideal. In addition, nitrile rubber may have some risk of leakage of substances that are not conducive to food safety, so it is generally less used in the food processing industry. Asbestos rubber is not preferred in the food processing industry because of the possible health risks of asbestos (asbestos fibers may cause lung diseases after being inhaled into the human body, etc.).
