Flange Sealing of Vacuum & the Magdeburg Hemispheres

In scientific history, certain experiments have fundamentally changed our understanding of the physical world. One such pivotal moment occurred on May 8, 1654, when Otto von Guericke conducted the Magdeburg Hemispheres Experiment. This remarkable demonstration not only captivated audiences of its time but also provided early insights into the use of gaskets in the pursuit of understanding vacuum and air pressure. It laid the groundwork for modern pumps and our comprehension of vacuum sealing.

The Genius of Otto von Guericke

Otto von Guericke was a man of many talents, born in the early 17th century. He was not just a scientist but also a mayor and a former crusader. His diverse experiences fueled his curiosity and drive for experimentation. Living in an era where the existence of a vacuum was hotly debated, Guericke sought to settle the question through innovative experimentation.

In 1650, Guericke invented a precursor to the modern air pump, featuring a piston and cylinder with one-way flap valves designed to draw air out of a container. This invention was central to his groundbreaking experiments.

The Magdeburg Hemispheres Experiment

On May 8, 1654, Guericke’s most famous experiment took place before Emperor Ferdinand III in Magdeburg. Using two large hollow copper hemispheres fitted with a leather gasket, Guericke aimed to demonstrate the power of vacuum. He meticulously greased the rims, placed a gasket between them, and sealed them together. A blacksmith operated the air pump to withdraw air from inside the sealed hemispheres, creating a vacuum.

As the air was pumped out, Guericke’s assistants joined in to help. The audience watched in awe as two teams of eight horses each were harnessed to the hemispheres and attempted to pull them apart. Despite their immense strength, the hemispheres remained sealed, held together solely by the external air pressure.

Guericke explained to the astonished crowd that the absence of air inside the hemispheres resulted in a powerful external force that surpassed the combined strength of 16 horses. When the air was let back into the hemispheres, they separated effortlessly, illustrating the concept of vacuum and atmospheric pressure.

Implications for Modern Technology

Guericke’s experiment not only provided groundbreaking insights into the nature of vacuum but also highlighted the importance of gaskets in sealing. This historical account reminds us that innovation and experimentation are at the heart of scientific progress. Guericke’s pioneering work serves as a testament to human curiosity and the power of ingenuity.

Vacuum Sealing in Power Generation

In the modern context, sealing a vacuum is crucial, especially in power generation. For instance, in fossil power plants, steam is transformed back into water, creating a vacuum at the end of the cycle. Valves and flanges within this vacuum can leak air, introducing dissolved oxygen (DO), which can cause hot spots and damage boiler tubes.

To tackle this, ultrasonic technology is used. Skilled technicians employ sensitive microphones to detect the sound of air being drawn into the valves and flanges. This allows power plant teams to identify and address leaks during scheduled outages, significantly reducing DO levels and protecting the boiler.

The Role of Bolting

Effective vacuum sealing depends heavily on precise bolting. Unlike pressurized systems, where pressure, temperature, and fluid dynamics are primary concerns, vacuum sealing requires meticulous attention to bolting patterns and torque. Properly executed bolting ensures the structural integrity of the system and prevents air leaks.


The Magdeburg Hemispheres Experiment is a landmark in scientific discovery, illustrating the power of vacuum and the importance of proper sealing. Otto von Guericke’s work laid the foundation for modern understanding and applications of vacuum sealing. Today, meticulous engineering and advanced technology continue to safeguard our energy production, emphasizing the enduring relevance of these principles.

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