Installation cost: Installation requires only an air line and a regulator.Compare this to the cost of a mechanical pump, especially if it must be explosion proof or made of an exotic material. Capital cost: The mini-eductor is an inexpensive device to purchase and install.Other terms used for the same device are Venturi pump, Bermoulli vacuum pump, jet pump, mini-eductor, mini-aspirator, … What are the advantages of using an eductor over using a mechanical pump?Īn eductor is a simple device that has many advantages over a mechanical pump. These terms are often used interchangeably. What is the difference between an eductor and an aspirator? The sample flow rate is significantly increased with the elevated sample pressure. This plot illustrates the effect of an elevated sample pressure while experiencing a 15 psig backpressure at the exhaust (atmospheric sample pressure, red 5 psig elevated sample pressure, blue). These curves shift significantly higher when an elevated sample pressure exists (see below). The flow rates are shown for 5 psig (blue) backpressure at the exhaust, 10 psig (red) backpressure and 15 psig (green) backpressure. This data is useful when it is necessary to return the sample to the process or to send it to a flare header. Below are curves that illustrate flow capacities vs motive pressure at different back pressuresīackpressure/flow rate curves: The above illustrates the sample or vacuum flow rate vs motive force for three different back pressures at the exhaust. Compensation for this condition requires that the motive pressure be increased. Often there is a backpressure at the exhaust. Can I still use an eductor if there is a backpressure?Īn eductor is used to draw samples from remote, positive or negative pressure sample points and are either vented, returned to the process or sent to a flare. I need to return the sample to a flare header. The sample can be diluted at a fixed ratio or returned to the process, depending on the requirements. natural gas lines, can be used to drive the eductor. Venting: Remove noxious vapors from a chemical process or vessel.Ĭan I use process or sample stream as the motive force to drive the eductor?Ī process stream which is at elevated pressure, e.g.Vacuum: Create a vacuum for evacuating vessels or lines.However, we also make customized eductors to suit your specific flow requirements. Our standard off-the-shelf eductors meet the majority of applications. Any pressurized gas (air, nitrogen, argon, natural gas, … ) can be used as the motive force that creates the vacuum flow. Mixing or dilution: The mini-eductor can be used to mix samples in a specific controlled ratio.The eductor can also be configured to return the sample to the process. Sampling: In process analytics for sampling process gases or aspirating stack gases for continuous analysis or for discrete sampling for lab analysis.The small mini eductors (or mini aspirators) that Jacobs Process Analytics offers are routinely used for: There are innumerable applications for this simple technology, from environmental sampling to gas cooking stoves to large scale dredging operations. ( view performance curves) Where can I use an eductor? For example, if a flow rate of 1 LPM is required for a sampling device the motive pressure can be reduced to 5 psig, reducing utility usage while meeting time delay requirement. The Motiv-Air-Torr can operate at a range of pressures, depending on sample flow requirements. Can I use a motive pressure at less than the supply pressure? Eductors are commonly used to draw stack samples for environmental analysis and to sample furnace exhaust to control combustion efficiency. less than atmospheric pressure?īecause an eductor creates a partial vacuum at the sample intake, these devices can be used to draw samples that are at reduced pressure. Can I draw a sample from a point that is at reduced pressure, i.e. Multiple sample lines can be drawn through a sample switching system or sinultaneously through multiple analyzers/sensors. The flow capacity can be divided among two or more sample lines/analyzers. (Click here for more complete discussion.) Can I use one eductor to draw samples from multiple points?Īn eductor often has the ability to deliver more flow than is required to meet flow rate or time delay for one system. Because the reduced pressure at the restriction creates a partial vacuum, this device can be used, among other applications, to extract samples from pipes, vent stacks, or ambient air or even to mix samples. It uses fluid mechanics to obtain work from energy stored in the motive fluid. This creates a partial vacuum in the eductor immediately after the orifice. Basically the eductor, often referred to as a Venturi pump, is a simple device that converts pressure to velocity when a fluid (liquid or gas) is forced through a restriction in an enclosed line.
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