Introduction
Scraped surface heat exchangers (SSHEs), also known as scraped surface exchangers (SSEs) are designed to process products that may be sensitive to fouling, shear or temperature variations. These heat exchangers are most commonly used in the dairy and food processing industries, but their broad range of features make them useful for numerous other applications.
SSHEs use a series of rotating blades or scrapers, which move along the walls of the heat exchanger to create a very thin film of product on the surface of the exchanger. This thin film allows for efficient thermal exchange.
Description
A scraped surface heat exchanger consists of several main components which work together to transfer heat between two fluids. These include the heat exchanger shells, scrapers, couplings and drives. The shells of the SSHE are made of stainless or carbon steel. The scrapers are mounted on shafts or rotors which are connected via couplings to motor drives.
The motor drives rotate the scrapers along the lengths of the shells. This scraping action creates a thin product film on the walls of the heat exchanger, allowing for efficient thermal exchange. As the product flows through the SSHE, the scrapers are continually moved along the walls, preventing product build-up. The scrapers are usually made of stainless steel or titanium.
Advantages
SSHEs offer several advantages over traditional shell-and-tube designs, which make them particularly well suited for certain applications. These include:
• The ability to operate at high temperatures and pressures
• Low fouling rates
• High heat transfer rates
• Ease of cleaning the heat exchanger
• High scalability for multiproduct applications
• Low maintenance requirements
• Excellent thermal efficiency
Applications
Scraped surface heat exchangers are used in a variety of industries and applications. The most common application is in the dairy and food processing industries, where SSHEs are used to pasteurize, homogenize and sterilize products. SSHEs are also used to dewater products such as miso, yogurt and cottage cheese.
SSHEs are also used in a variety of other applications. These include petrochemical, pharmaceutical, mineral oil, chemical and pet food processing. In addition, SSHEs are a popular choice for cryogenic applications, where extreme temperatures are used for rapid cooling.
Conclusion
Scraped surface heat exchangers offer a number of advantages over traditional designs. These heat exchangers have low fouling and high heat transfer rates, and are easy to clean and maintain. Because of these features, they are a popular choice for dairy and food processing applications, as well as other industries.
