Fore vacuum pumps are defined as those which exhaust to atmospheric pressure. They are also required to support secondary pumps or to attain the initial conditions for their operation. There are two types of fore vacuum pumps:
For a vacuum pump system, a vital consideration in its design is the conductance. Conductance in vacuum systems is the characteristic of a vacuum component or system to readily allow the flow of gas and can be thought of as the inverse of resistance to flow. Its units are that of the volumetric capacity of gas flow in a passive component (or aggregate component of a vacuum system), such as an opening or a pipe, divided by time.
Anyone without a deep understanding or knowledge of pumps might think that vacuum generation is simply a question of “plugging in a pump”, starting it up and waiting for the vacuum to drop to the required level.
Laboratory technicians and scientists regularly use vacuum pumps (frequently of the bench-top variety) for a range of tasks including aspirating/filtering, controlling or inducing solvent evaporation in concentrators, as well as in gel driers, vacuum ovens, desiccators and rotary evaporators.
Rotary vane pumps are considered wet, positive displacement pumps, with the term “wet” denoting that the gases being pumped are exposed to oil. The significant characteristic of oil sealed rotary vane (OSRV) pumps is the use of oil as a sealant, which is not found in ‘dry’ pumps.
Described as ‘a space in which the pressure is below surrounding atmospheric pressure’, vacuum science is a subject and concept that has stimulated many great minds for millennia.
The origins of vacuum science can be traced back to as early as the 4th century when Aristotle stated that ‘nature abhors a vacuum’.
