Welcome to Flightinfo.com

  • Register now and join the discussion
  • Friendliest aviation Ccmmunity on the web
  • Modern site for PC's, Phones, Tablets - no 3rd party apps required
  • Ask questions, help others, promote aviation
  • Share the passion for aviation
  • Invite everyone to Flightinfo.com and let's have fun

Jet pump

Welcome to Flightinfo.com

  • Register now and join the discussion
  • Modern secure site, no 3rd party apps required
  • Invite your friends
  • Share the passion of aviation
  • Friendliest aviation community on the web
Ever own a waterbed?

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

Latest resources

Back
Top