Plumbing question

[Myka]

Originally Posted by banditpowdercoat

But were not changing the pump. What would your 1200PSI pump out out with a open 4" hose, No nozzle. I guarantee you it wont be 1200PSI. But it still woould take your toes and whole feet off if it was exiting the hose at 1200PSI

Ooooooh but that was my point!!! If it's 1200 psi out of a 1/8" nozzle, it ain't gonna be 1200 psi out of a 4" tube.

[kari]

Illustration and graph,
http://home.earthlink.net/~mmc1919/venturi.html

If it's on the internet, it must be true.

[mark]

Myka, think your need to separate pressure and flow as they are not the same thing. As for your vac truck could have a 4" line with a 1/8" nozzle and it still would probably take your toes off with the orginal pump. Reason you wouldn't have a 4" line is having to drag around the weight of the water in the hose.

[banditpowdercoat]

Originally Posted by Myka

Ooooooh but that was my point!!! If it's 1200 psi out of a 1/8" nozzle, it ain't gonna be 1200 psi out of a 4" tube.

OH. LOL I had to many beers last night

[sphelps]

Originally Posted by oilfieldsafety

So I was plumbing up my new (used) 90 and a question came to mind, this is my first system that will have a sump so I was more or less going to match what I have seen done on other systems that I have seen. Most of these have been plumbed with 1" line running from the pump to the tank even though the output of the pump was 1/2 or 3/4 inch. Now I assume that this was done with friction in mind and wanting to get max flow, but by going to a larger diameter pipe won't you increase your head pressure due to weight of the water column and in fact decrease your flow? Thoughts?

Shane

Originally Posted by Myka

Ooooooh but that was my point!!! If it's 1200 psi out of a 1/8" nozzle, it ain't gonna be 1200 psi out of a 4" tube.

Cat urine glows under a black-light

[banditpowdercoat]

But back to the basic question. Does head pressure change at the pump, when using larger diameter pipes for tank return.

NO, it remains the same. The pressure the pump see's is equivalent to the weight of water equaling the volume of a pipe the same diameter as the pump outlet, times the head height.

Now as far as friction losses, they are regardless of head height. Friction losses will happen on horizontal runs as well as vertical. If said pump was loosing flow (GPH) due to frictional losses, then yes, upping pipe size can gain back some lost GPH.

Heres a chart comparing firehose sizes and friction losses per 100' of hose. Distance and flow determine friction losses, not head height



Losses in PSI of firehose per GPM flow @ 100 PSI pump pressure

1.5" diameter
GPM/ PSI Loss

50 6.3
100 25
150 56.3

2" diameter

50 1.7
100 6.6
150 14.8
200 26.3
250 41.1
300 59.2

2.5" diameter

150 4.9
200 8.7
250 13.5
300 19.5

And for elevation, add 0.5 PSI for each foot

[Myka]

Here I thought the original question was well answered already, and that we were delving off further into the topic...???

[banditpowdercoat]

lol, I'll shut up now

[golf nut]

BTW there is no head loss in a closed loop

[sphelps]

Originally Posted by Myka

Here I thought the original question was well answered already, and that we were delving off further into the topic...???

What tends to happen when people figure out they're wrong is they go on and on about something completely irrelevant as a means to justify their original statement. We can't always be right so when we're not we should just cut the BS and admit it