The Venturi Principle

A venturi creates a constriction within a pipe (classically an hourglass shape) that varies the flow characteristics of a fluid (either liquid or gas) travelling through the tube.  As the fluid velocity in the throat is increased there is a consequential drop in pressure.  Italian scientist Giovanni B Venturi (1746-1822) was the first to observe this phenomenon.

The fact that a pressure drop accompanies an increased flow velocity is fundamental to the laws of fluid dynamics.  Swiss mathematician, Daniel Bernoulli, derived the interrelationship between pressure, velocity and other physical properties of fluid in 1738. Classically, his theorem is used in the design of aircraft wings to create lift from the flow of air over the wing profile.

There are basically two applications for a venturi.  By attaching manometers to three sections of the tube, the pressure drop can be measured and the flow rate through the throat calculated. This is termed a Venturi Meter.

More commonly, a venturi can use this negative pressure to draw a second fluid into the primary flow.  This effect has found many applications across a range of industries. However, the basic mechanism has remained the same for almost 200 years.
That is, until the arrival of Airmaster!

In the mid 1990s David RM Short, Plumber, Former Fire-fighter and Koi Carp Keeper, brought naïve logic and lateral thinking to bear to fundamentally re-invent the venturi . His award winning invention was subsequently evaluated and qualified by the Techische Universitat Hamburg-Harburg fluid dynamics department in Germany (see Performance Data). The patented Airmaster not only delivers improved performance over conventional venturis, it can also extend its utility by enabling precise adjustment of the process.
1 water flow.    2 less constriction around the aquafoil.   3 the Aquafoil.
A conventional venturi carries inherent limitations.  The constriction strangles the primary flow resulting in backpressure that can burden a pump with unnecessary load increasing energy costs and shortening its serviceable life.  In addition, the venturi effect is notorious fickle fluctuating with slight changes in flow rate, temperature, viscosity and other parameters.  The Airmaster leaves behind these penalties offering benefits for new and existing applications.

Fluid dynamics is a challenging topic and the venturi effect is frequently misunderstood or misrepresented.  For additional information on this subject we recommend you visit
http://www.grc.nasa.gov/WWW/K-12/airplane/bern.html &
http://www.grc.nasa.gov/WWW/K-12/airplane/wrong3.html &
How Airmaster Works - A Unique Process

The mechanism embodied in Airmaster provides an efficient means of transferring oxygen from air to water. Using the kinetic energy of water flowing over a hollow insert within the Airmaster tube the device activates a venturi effect to induce air. However, while Airmaster applies the venturi principles in its operation it is quite different from a conventional venturi.

A venturi creates a constriction within a pipe (classically an hourglass shape) that builds backpressure up-stream and effects a negative pressure down-stream of the constriction.  As the volume of fluid is forced through the reduced diameter fluid dynamic laws determine that the increased flow velocity be accompanied by a pressure drop. A venturi uses this negative pressure to draw air into the primary fluid.  Italian scientist GB Venturi (1746-1822) first observed this phenomenon which is also closely related to Bernoulli's theorem.  Swiss mathematician, Daniel Bernoulli, derived the interrelationship between pressure, velocity and other physical properties of fluid in 1738. Classically, his theorem is used in the design of aircraft wings to create lift from the flow of air over the wing profile.

A conventional venturi carries with it penalties for aquatics systems.  The constriction and its resulting backpressure can substantially reduce flow and burden the pump with unnecessary load increasing energy costs and shortening its serviceable life.  In addition, the air may be drawn in erratically and in large bubbles.

The unique, patented design employed by Airmaster replaces the constriction with an obstruction.  This also narrows the cross-sectional area of the tube to activate the venturi effect but with the streamlined design of the insert, backpressure is reduced to a fraction of that of a venturi.  Apart from the obvious efficiency gains in energy and pump life there are other features of Airmaster that separate it from a venturi.

The insert is hollow with an air inlet pipe extending out of the tube to atmosphere.  Tiny holes are set downstream of the apex of the insert to align with the negative pressure point.  Air is induced through these tiny holes and delivered into the designed turbulence in the form of microscopic bubbles. Small bubbles impart oxygen more readily than larger ones and oxygen transfer occurs with a high rate of efficiency.   The excess air and nitrogen bubbles are carried out with the stream to beneficial effect adding further oxygenation and providing ventilation for water.

In many circumstances the Airmaster can be fitted into an existing circulation system avoiding the necessity of an independent power source and effectively providing "free" oxygenation. In circumstances where Airmaster is supplied as an integrated system (Airmaster Island) its oxygenation efficiency compares most favourably with other integrally powered methods.

Airmaster is a patented, award-winning invention that has been extensively researched and developed at Hamburg-Harburg University, Germany. Performance data is available for a wide array of conditions and specific applications can be considered by request.

1.  WATER is  pumped through the Airmaster

2.  A it passes through the neck, the water velocity increases, this creates low pressure on the backslope of the aquafoil (the same effect as on an airplane wing)

3.  Air is drawn in through the minute holes in the aquafoil backslope generating thousands of microbubbles per cubic centimeter

So the air surface area to water ratio is enormous, giving the most efficient oxygen transfer known and results in 100% oxygenation of all the water passing the aquafoil.
(results verified by Hamburg University fluids dynamics laboratory)

This is the result.
Patented aquafoil technology
at the center of every Airmaster