I want to introduce you guys the best aeration method known.
what it is:
The fluid velocity
must increase through the constriction to satisfy the equation of continuity
, while its pressure must decrease due to conservation of energy
: the gain in kinetic energy
is balanced by a drop in pressure or a pressure gradient force
. An equation for the drop in pressure due to the Venturi effect may be derived from a combination of Bernoulli's principle
and the equation of continuity.
in simple terms:
When you force water that is travelling through a tube through a constriction (make the tube narrower) the fluid increases its speed to get through the narrow part. This in turn reduces the pressure of the fluid so when it travels through the narrow part in the tube there is a net vacuum there, and with a small hole it will suck air into the tube mixing it with water.
This technology is used in everything from Rocket Science to Aerodynamics. Please review the video links below before proceeding-
Venturi Nozzle mixing air and water:
[ame=http://www.youtube.com/watch?v=1CC0Cs0Gpu8]YouTube - Venturi transparent[/ame]
Venturi being used in a small aquarium:
[ame=http://www.youtube.com/watch?v=X9U5kI5MFgE]YouTube - AirDuck venturi aerator[/ame]
Technology implemented by the Venturi used in commercial aeration for lakes:
[ame=http://www.youtube.com/watch?v=2Iaqx-b4VLU&feature=related]YouTube - Pond & Lake Aerator OASE Aqua Air[/ame]
[ame=http://www.youtube.com/watch?v=xHiLoZIjJ-0&feature=related]YouTube - Ventus Aerator-single head big frame[/ame]DIY VENTURI:take a 3/4" ball valve
unscrew bolt holding spigot
drill hole or screw into the center of the spigot hinge holding ball in place
connect 3/16" air hose to top of spiqot
now attach an air valve to control your bubble size- recommended pump at least 400gph for good flow. put the venturi after your water pump on a verticle plane or downwards angle and make sure it draws a vacuum in the airline. the water being pumped to all your beds will now be a superoxygenated foam. this device is like using 10 air pumps.
you can use the venturi airline to draw in nutrients and mix them in the throat of the venturi. run a slight angle after the venturi so the mix is augmented through a vortex motion as demonstrated by bubbles when the venturi is drawing in air. the venturi is used to mix fluid and gas in industrial and commercial applications.
the venturi works by drawing in air from the narrow point in a waterline
this works because the water speeds up as the waterline narrows, and
when the water passes through the valve it has to speed up through the small hole. when water speeds up, it loses its pressure and creates a negative pressure (vacuum) inside the narrow area. the vacuum draws in air and mixes it with the water very efficiently. depending on adjustments made to the shape of the airhole, power of pump, gravity, length of line, and angulature of line there is a greater degree of efficiency (finer bubbles, more air mixed with less water resistance). This fitting is very easy to make and is worth the time.
If you have any question please post, I would be happy to explain any details...
The Venturi effect may be observed or used in the following:
- Cargo Eductors on Oil, Product and Chemical ship tankers
- Inspirators that mix air and flammable gas in grills, gas stoves, Bunsen burners and airbrushes
- Water aspirators that produce a partial vacuum using the kinetic energy from the faucet water pressure
- Steam siphons using the kinetic energy from the steam pressure to create a partial vacuum
- Atomizers that disperse perfume or spray paint (i.e. from a spray gun).
- Foam firefighting nozzles and extinguishers
- Carburetors that use the effect to suck gasoline into an engine's intake air stream
- Wine aerators, used to infuse air into wine as it is poured into a glass
- The capillaries of the human circulatory system, where it indicates aortic regurgitation
- Aortic insufficiency is a chronic heart condition that occurs when the aortic valve's initial large stroke volume is released and the Venturi effect draws the walls together, which obstructs blood flow, which leads to a Pulsus Bisferiens.
- Protein skimmers (filtration devices for saltwater aquaria)
- In automated pool cleaners that use pressure-side water flow to collect sediment and debris
- The barrel of the modern-day clarinet, which uses a reverse taper to speed the air down the tube, enabling better tone, response and intonation
- Compressed air operated industrial vacuum cleaners
- Venturi scrubbers used to clean flue gas emissions
- Injectors (also called ejectors) used to add chlorine gas to water treatment chlorination systems
- Sand blasters used to draw fine sand in and mix it with air
- Emptying bilge water from a moving boat through a small waste gate in the hull—the air pressure inside the moving boat is greater than the water sliding by beneath
- A scuba diving regulator to assist the flow of air once it starts flowing
- Modern vaporizers to optimize efficiency
- In Venturi masks used in medical oxygen therapy
- In recoilless rifles to decrease the recoil of firing
- The diffuser on an automobile
- Large cities where wind is forced between buildings
A simple way to demonstrate the Venturi effect is to squeeze and release a flexible hose
in which fluid is flowing: the partial vacuum produced in the constriction is sufficient to keep the hose collapsed.
Venturi tubes are also used to measure the speed of a fluid, by measuring pressure changes at different segments of the device. Placing a liquid in a U-shaped tube and connecting the ends of the tubes to both ends of a Venturi is all that is needed. When the fluid flows though the Venturi the pressure in the two ends of the tube will differ, forcing the liquid to the "low pressure" side. The amount of that move can be calibrated to the
speed of the fluid flow.
Edited by geneticengineer, 23 April 2010 - 03:31 PM.