Tag: pressure booster

Venturi Effect in Use

Published on by jasonkirbyLeave a comment

The Venturi effect describes the phenomenon where a fluid, such as air or water, accelerates as it passes through a constricted section, resulting in a decrease in pressure. This occurs because the fluid is drawn into the narrower area, and the increase in velocity leads to a corresponding drop in pressure. The effect is named after Giovanni Battista Venturi, who first articulated this principle in 1797.

A perfect example of the Venturi Effect can be found in our Air Amplifiers. Compressed air enters through the air inlet and flows into an annular chamber, where it is accelerated through a small ring nozzle. This high-velocity primary airstream follows the Coanda effect, guiding it toward the outlet. As a result, a low-pressure zone forms at the center, drawing in a significant volume of surrounding air into the primary flow. The mixture of the primary airstream and the surrounding air is then expelled from the Air Amplifier at a high volume and velocity.

The Venturi Effect is represented in amplification ratios. A ratio represents the relationship between two quantities, indicating how many times one value is contained within another. In the case of the Super Air Knife, this ratio illustrates the volume of ambient air that is drawn in alongside the primary flow of compressed air. With an impressive amplification ratio of 40:1, the Super Air Knife incorporates 40 parts of ambient air for every single part of compressed air, making it one of the most efficient air-operated knives available. This addition of mass enhances the device’s ability to deliver a powerful force, enabling it to perform more effectively in various applications.

The Venturi effect is integral to various EXAIR products designed for cooling, drying, and cleaning, alongside our vacuum generators. If your facility has a process that could benefit from an Intelligent Compressed Air solution, please reach out to us. We would be pleased to discuss your specific application and develop a solution that not only lowers your compressed air expenses but also enhances worker safety.

Jason Kirby
Application Engineer
Email: jasonkirby@exair.com
Twitter: @EXAIR_jk

Intelligent Compressed Air: Two Different Products Called “Air Amplifiers”

Published on by Russ BowmanLeave a comment
A 2psi change in compressor discharge pressure equates to a 1% change in compressor power consumption.

They say that necessity is the mother of invention, so it’s no coincidence that mechanical means of compressing air came about in the early days of the Industrial Revolution, eventually becoming known as the “4th Utility” along with electricity, water, and gas. For most of the 20th Century, compressed air system pressure was commonly generated in the neighborhood of 100psig, although many modern industrial air compressors can be operated at 160 to 200psig. Operating an air compressor at higher discharge pressure increases the cost of operation, though, so it’s in EVERYONE ‘S best interests to run compressed air systems at the lowest pressure possible, that still gets the job done for all the air-operated gear in the facility.

So, what if most of your compressed air loads operate at 80-100psig, but one (or a handful) needs 120psig? Or 160psig? Or even higher? Increasing your compressor discharge pressure from 100psig to 160psig means you’re using 30% more power to run the compressor. That’s a LOT for one (or a handful) of operations.

Good news: the laws of physics say that pressure is the amount force applied to a specific area…as in pounds(force) per square inch, or psi. So, if we apply a certain pressure to a large diameter piston, and attach that with a shaft to another smaller diameter piston, the amount of force doesn’t change, but the area does, so the pressure on the other side of the smaller piston HAS to:

Let’s say the primary pressure (P1) is 100psi, and the primary piston (D1) is 4″ in diameter, with a surface area of 12.56 in2. That means the force applied to the primary piston (D1) is : 100 lbf/in2 x 12.56 in2 = 1,256 lbf.
This is the same force applied to the air on the other side of the secondary piston (D2), which has a diameter of 2″ and a surface area of 3.14 in2. Since pressure is force divided by area, that 1,256 lbf applied to 3.14 in2 results in a secondary pressure (P2) of 400psi.

This is the basic theory behind how air (pressure) amplifiers – also known as booster regulators – work. Essentially, you’re trading compressed air flow (into the larger cylinder) for pressure. Now, if EVERYTHING you operate needs higher pressure, the best way to do that is to increase the compressor discharge pressure. But if you only have one, or a few, loads that need higher pressure, the increase in air consumption for those loads is likely less costly than compressing the air to a higher pressure than is needed for the majority of your loads.

The other type of air amplifier is the one that EXAIR manufactures – it’s an air FLOW amplifier, and here’s how it works:

In this case, we’re trading pressure for flow, and getting a much higher total developed air flow rate than just the amount of compressed air it uses. Not only does the entrained air make them incredibly efficient, it also develops a low-velocity boundary layer that attenuates the sound level of the total air flow. They can be used for cooling, drying, cleaning, ventilation, fume exhaust, and even material conveying, especially if the material to be conveyed is very light, or already airborne.

With (16) models to choose from, EXAIR Air Amplifiers are a quick and easy way to provide a tremendous amount of cooling air flow from a compact, lightweight product.

EXAIR Air Amplifiers come in a range of sizes, from 3/4″ to 8″. Super Air Amplifiers are lightweight, durable aluminum, and Adjustable Air Amplifiers are available in aluminum or 303SS. If you’d like to find out more about them, give me a call.

Russ Bowman, CCASS

Application Engineer
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