Plumbing question

[golf nut]

Originally Posted by Myka

Maybe I'm not being clear about what I mean, or maybe you're wrong.

We use say 1200 psi to go through a 5/8" hose then through a 1/8" fitting on the end (we use this on Hydro-Vac trucks to cut the ground), and voila! It will cut your toes off. If we use 1200 psi pumped through a 3" hose (which you would never be able to hang onto, and you'd need a muuuuuuuch bigger pump to get 1200 psi out the end of a 3" hose), and you wouldn't hurt your toes with it.

So...slap your fancy words (pressure, head pressure, velocity, psi, flow, whateeeever) on that equation, and tell me what the heck you mean that I am wrong.

I think the pump comes into play here, I agree with what you can do to cut my toes off (God forbid) but you are using a positive displacement pump that doesn't know the meaning of the word backpressure, a typical aquarium pump doesn't come close to 3 psi and simply doesn't do what a hydraulic pump is capable of, in effect you are both right.

[sphelps]

Originally Posted by Myka

Maybe I'm not being clear about what I mean, or maybe you're wrong.

We use say 1200 psi to go through a 5/8" hose then through a 1/8" fitting on the end (we use this on Hydro-Vac trucks to cut the ground), and voila! It will cut your toes off. If we use 1200 psi pumped through a 3" hose (which you would never be able to hang onto, and you'd need a muuuuuuuch bigger pump to get 1200 psi out the end of a 3" hose), and you wouldn't hurt your toes with it.

So...slap your fancy words (pressure, head pressure, velocity, psi, flow, whateeeever) on that equation, and tell me what the heck you mean that I am wrong.

Adding a nozzle will increase dynamic pressure within the nozzle and increase the head pressure on the pump, but this will result in less flow on a centrifugal pump. In addition as stated positive displacement pumps are not effected by head pressure, they pump the same amount of fluid no matter what. Of course they do have a maximum operating pressure before something blows up which is why such pumps will have a release valve for safety.

You can't relate such systems to aquariums, we use centrifugal style pumps where head pressure is relevant, I'm actually pretty confused on what you argument is at this point

[Myka]

Originally Posted by sphelps

I'm actually pretty confused on what you argument is at this point

LMAO!!!

I give up on you, you aren't understanding.