How does a vacuum pump "remove air," creating an indispensable airless environment for modern technology?
Publish Time: 2025-11-11
In daily life, we rarely perceive the existence of "air," but in scientific research, industrial manufacturing, and even healthcare, removing air and creating a vacuum is a fundamental and crucial technological requirement. From the precision deposition of semiconductor chips to the preservation and sealing of food packaging; from infection control in hospital negative pressure wards to the simulation testing of spacecraft components—these seemingly disparate scenarios all rely on a core piece of equipment: the vacuum pump. Like a silent "air transporter," it continuously extracts gas from sealed spaces, creating different pressure environments ranging from low vacuum to ultra-high vacuum.A vacuum is not "absolute emptiness," but rather refers to a state where the gas pressure is significantly lower than standard atmospheric pressure (101.3 kPa). Vacuum pumps can be categorized into rough vacuum (10⁵–10³ Pa), medium vacuum (10³–10⁻¹ Pa), high vacuum (10⁻¹–10⁻⁶ Pa), and ultra-high vacuum (<10⁻⁶ Pa) depending on the required vacuum level. Different applications have varying vacuum requirements: food packaging only requires rough vacuum to inhibit bacterial growth; while manufacturing a 7-nanometer chip requires atomic-level thin-film deposition in an ultra-high vacuum to avoid interference from any gas molecules.Vacuum pumps are the core tool for achieving this goal. Their working principles are mainly divided into two categories: positive displacement and momentum transfer. The most common rotary vane, piston, or diaphragm vacuum pumps are positive displacement pumps. They periodically change the volume of the pump chamber through mechanical motion, drawing in gas and compressing it before expelling it. They are suitable for rough to medium vacuum ranges. These pumps are simple in structure, low in cost, and widely used in laboratories, dental equipment, or small packaging machines.For even higher vacuum requirements, momentum transfer pumps, such as turbomolecular pumps or diffusion pumps, are needed. These pumps do not directly "compress" gas; instead, they utilize high-speed rotating blades or high-temperature steam to impact gas molecules, directing them towards the exhaust port. These pumps cannot operate independently and must be used in series with a backing pump (such as a rotary vane pump) to form a multi-stage pumping system. For example, in electron microscopes or particle accelerators, turbomolecular pumps reduce chamber pressure to the order of 10⁻⁷ Pa, allowing the electron beam to travel unimpeded.In recent years, dry vacuum pumps have rapidly gained popularity due to their environmental and cleanliness advantages. While traditional oil-sealed pumps offer stable performance, lubricating oil can flow back and contaminate process chambers; dry pumps, with their oil-free design (such as screw or claw structures), avoid media contamination, making them particularly suitable for industries with extremely high cleanliness requirements, such as semiconductors, photovoltaics, and biomedicine.The applications of vacuum pumps far exceed expectations. In the new energy field, lithium battery electrolyte filling requires the removal of air bubbles in a vacuum environment; in materials science, vacuum heat treatment prevents metal oxidation; and in daily life, the packaging of coffee capsules and dehydrated vegetables relies on vacuum to extend shelf life. Even in environmental engineering, vacuum pumping technology is used for soil remediation or biogas collection.Of course, the design of a vacuum system is extremely complex, requiring comprehensive consideration of pumping speed, ultimate vacuum, corrosion resistance, noise, and energy consumption. A high-performance vacuum pump often integrates precision mechanics, fluid mechanics, and automatic control.Ultimately, the value of a vacuum pump lies in its ability to allow humanity to "manipulate nothingness." It doesn't produce products, yet it provides the necessary conditions for countless cutting-edge technologies; it is inconspicuous, yet it is the invisible pillar of modern industry and scientific research. When chips grow nanoscale circuits in a vacuum, when life-saving drugs are freeze-dried in a sterile vacuum environment, that quietly operating vacuum pump, with its silent power, removes air, leaving behind possibilities. Between "having" and "not having," it constructs a clean passage to the future.
