Eductors

Perma Pure eductors, or aspirators, provide a non-mechanical means of transporting or mixing a sample stream. An eductor is a device in which the energy of one stream is used to pump another. The pumping gas, typically compressed air, enters through the nozzle at the right an passes through the venturi nozzle and out the discharge opening at the left (See figure below). As it passes into the nozzle, it develops a vacuum at the suction port that causes the sample in the suction chamber to be entrained with the stream and be delivered through the exhaust port.

Besides the obvious advantages of having no moving parts, and requiring no lubrication, Perma Pure eductors are manufactured from corrosion resistant Teflon block and are available with either a stainless steel or fluorocarbon nozzle.

There are a variety of applications which require the use of an eductor.

• The mixing of two sample streams, either liquids or gases.

• If the sample source, such as a stack or vent, is under a vacuum, a greater vacuum must be created to redirect a portion of the flow to provide a sample stream. In this case, the eductor would be located after the analyzer so that the sample does not become diluted with the compressed air. 

• If the environment is classified as hazardous or explosive, an eductor can be used as a "non-mechanical" pump since there are no moving parts and no electricity is required. Note that the byproduct will be diluted or aerated by the compressed air stream.

• To pull entrained liquid from a coalescing filter when a gas stream is under vacuum, Perma Pure often supplies sampling systems implementing this feature. Click here for more automatic drain setup information.