Jet pump

flyboyzz1

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I have a jet systems quiz tomorrow. Can anyone tell me about a jet pump?
 

lowslow

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Ever own a waterbed?

Think about the day you emptied it, and there is your jet, or, motive flow pump.
 

EagleRJ

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A jet pump uses a small quantity of high-pressure fuel to move a larger quantity of fuel through an orifice.

Using the waterbed analogy, imagine you cut a hole in the top of your waterbed, and the water is just sitting there. Now take a garden hose with a nozzle and submerge it in the hole, pointing up. You'll start emptying the waterbed, since the garden hose will move the rest of the water through the hole.
 

flyboyzz1

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EagleRJ said:
A jet pump uses a small quantity of high-pressure fuel to move a larger quantity of fuel through an orifice.

Using the waterbed analogy, imagine you cut a hole in the top of your waterbed, and the water is just sitting there. Now take a garden hose with a nozzle and submerge it in the hole, pointing up. You'll start emptying the waterbed, since the garden hose will move the rest of the water through the hole.
makes sense thanks
 

avbug

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A jet pump is a fuel or air pump without moving parts. In the case or a jet fuel pump, a small amount of fuel from the aircraft engine driven fuel pump is routed to the jet pump. It is squired through a passage that is a venturi. As it passes through the venturi, pressure drops. This pressure drop is used to draw fuel out of the tank, and is the "pumping action." The jet pump uses existing fuel flow to move other fuel. The only control needed is a valve somewhere in the system to shut off or allow to flow the existing fuel, which is also called the "motive fuel."

The same thing occurs in most pressurization systems. Generally somewhere in the system is a jet pump. It pushes air, usually bleed air, through a venturi, causing a pressure drop. Exactly like what happens in an older venturi tube on the side of the an older airplane, or what happens in your carburetor. This lower pressure creates reduced air pressure in a line, and is used as a reference source or vacum source to get the pressurization controller and components do do certain things (such as open outflow valves, etc).

A jet pump is nothing more than a valve that uses an existing fluid, fuel or air, to move the same kind of fluid around. It does so by squiring fluid through a restriction to create a pressure drop.
 

starvingcfi

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avbug. is there nothing you don't know?

...and is that considered a double negative?
 

DGdaPilot

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starvingcfi said:
avbug. is there nothing you don't know?

...and is that considered a double negative?

Of course....he doesn't know what I had for breakfast this morning!

And double negatives?....twice the negative, twice the fun!
 

Greg

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Starving, you are a Boston poser. You know you want to put that Blue Devils hat back on. Oh yeah Duff hit 18!! But you already knew that.
 
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Lead Sled

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A good example of a jet pump can be found in many new toilets - some of those babys can really get with the program.

'Sled
 

EagleRJ

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Lead Sled said:
A good example of a jet pump can be found in many new toilets - some of those babys can really get with the program.

'Sled

Hey, that's a good example of a jet pump!

It's just that it isn't pumping....uh.....jet fuel. :D
 

FN FAL

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EagleRJ said:
Hey, that's a good example of a jet pump!

It's just that it isn't pumping....uh.....jet fuel. :D
That's not new tech, our ship used pressure from the fire mains to provide water pressure for the eductors in the toilets.
 

FN FAL

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Foxcow said:
a.k.a. ejector?
http://www.foxvalve.com/main.html
Eductors, ejectors, venturi's. On the link above is the website for a manufacturer of eductors, ejectors and venturi's. If you click on the hyperlinks under the product descriptions, there's even more detailed images and explainations.
 
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