by Jenny Knodell, IQS Editor
In the mid 1600s, a German mayor of a small town performed a trick using 2 metal half-spheres and a team of sixteen horses to entertain some houseguests. It was the first time he put his invention—a piston and air gun cylinder with two-way flaps designed to pull air out of whatever vessel it was connected to—to use in front of other people. The mayor, named Otto von Guericke, joined the two copper hemispheres together and pumped the air out using his contraption. He then harnessed eight horses to each half. The result? An astonished audience, completely inseparable copper hemispheres and the very first demonstration of a vacuum pump. It didn’t take long for this trick to gain popularity, and Guericke began performing in the German court with more and more horses. The power of a vacuum quickly caught the eye of scientists, who began using vacuum pumps to study properties of gasses and electricity. Today, you’d be hard pressed to find a single industrial factory or experimentation facility that doesn’t use a vacuum pump.
Copper cylinders in Guericke demonstration.
Modern vacuum pump systems convert mechanical force from a rotating component like a piston or rotary vane to pneumatic force by removing all air and gasses from a specific space. This creates a suction and pneumatic or hydraulic flow. Their design hasn’t changed too much from the days of Guericke, but vacuum pumps are a vital component in our modern world. Without them, flight instruments, air conditioning systems, TVs, cars and modern eyeglasses would not exist; they even function in an aircraft if all electricity has failed! This technology has evolved into a major necessity for the modern lifestyle. They are necessary for the processing of semiconductors, power brakes and cruise control in vehicles, and vacuum tubes that are used in microwaves and some older televisions. Vacuum pumps are used in the production of safety glass, which is the most common type of glass for public areas, as well as DVDs and PCs.
Oil sealed vacuum pump photo courtesy of Dekker Vacuum Technologies, Inc.
Now that you are convinced that vacuum pumps are extremely important, let’s look into the different kinds that are used today. Every size of vacuum pump uses less power than air compressors; small vacuum pumps are highly efficient, but are easily overheated if used continuously. So, for continuous pumping, larger pumps are used. Many pumps are lubricated with oil. This provides a higher level of vacuum because the oil gives a greater seal between moving parts. Rotary vane vacuum pumps are oil sealed, and therefore have a smaller foot print and can pump clean, dry, non-reactive gasses. However, the oil may contaminate. If contamination is a concern, costly downstream oil separators are necessary. In cases of cost efficiency, oilless vacuum pumps are used more often because they do not require added systems.
Rotary vane vacuum pump photo courtesy of Vacuubrand, Inc.