Laboratory Vacuum Pumps

Laboratory Vacuum Pumps

Laboratory vacuum pumps are devices that remove gas molecules from a sealed volume, creating a vacuum that is used for medical and scientific applications. Vacuum pumps change the mechanical force of a rotating part into pneumatic force by removing gas from the volume which creates suction and pneumatic or hydraulic flow. There are dozens of variations of vacuum pumps, including some that have been adapted specifically for laboratory use. Laboratory vacuum pumps have special features that make them suitable for use with tight spaces, delicate equipment, sanitary conditions and a variety of substances. Sound insulation or mufflers provide quiet operation. Most are dry vacuum pumps, meaning that they run with oil lubrication and have no sliding parts. Other laboratory pumps have vacuum concentrators and drying systems. Inlet water traps and aspirators remove moisture, and the exhausted air is clean and particle free. Vacuum pumps are typically constructed of heavy duty stainless steel because it is sanitary and can withstand the conditions inside the vacuum chamber. If other parts like gaskets are made of plastic or rubber they should not boil away or release gasses that would interfere with the operation or effectiveness. Vacuum pumps have an extensive range of applications in and out of the lab and are used for many industrial purposes. Within the laboratory setting, vacuum pumps are used in semiconductor processing, suction tools, electron microscopy and for analytical instrumentation to analyze substances and materials. Vacuums can be used to achieve very cold temperatures and to create a particle-free surface on which to conduct experiments.

Perfect vacuums exist only in theory because achieving a gaseous pressure of exactly zero is impossible. Though vacuum pumps have advanced in technology and ability, even ultra high pumps are unable to create a completely particle-free chamber. Rotary vane pumps are commonly used in laboratories, but scroll pumps, piston pumps, diaphragm pumps, liquid ring pumps, momentum transfer pumps, cryopumps and other vacuum pumps are available as well. Of the many different kinds, there are three main categories of vacuum pumps: positive displacement, momentum transfer and entrapment pumps. Positive displacement pumps enlarge one cavity within a chamber while compressing another to create a vacuum, similar to how a piston in a combustion engine works. Momentum transfer pumps treat gases like liquids by bringing them into contact with solid surfaces to create momentum that carries the molecules out of the vacuum chamber and through the exhaust. Entrapment pumps rapidly heat and/or cool the molecules to compress and trap them in a solid or absorbed state. Another way to categorize vacuum pumps is by identifying whether or not they use oil for lubrication. Wet pumps require oil and are able to deliver high level performance for long periods of time. However, contamination is a possibility so wet vacuum pumps are often paired with devices to prevent oil intake. Dry pumps do not need oil lubrication and consequently are used most frequently. Laboratory vacuum pumps tend to be dry pumps to ensure a clean, contaminate-free system.