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# What's the relationship between pressure and range?

Gentlmen,I did a test.A squirt gun with 0.2MPA's pressure can shoot to 20 Metre's range.But when I increase the pressure to 1.2MPA,the range became 35 Metre.Before this test,I thought pressure of squirt gun and range of squirt gun should be in direct proportion.That is to say,1.2MPA should be 120M.But the result is,1.2MPA pressure can only shoot water for only 35Metre!I am really confused and I hope some fellows could tell me something.

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### Replies to This Discussion

As pressure increases range increases to the point of max range for that given Gallons per minute (GPM) supply.
Dave, PSI is PSI. If you were open a nozzle a quarter it is still the same PSI. The only thing you are stealing is GPM flow. Do not get the two confused.

But the diameter of the nozzle tip is also a factor with this squirt gun test.
Ahhhhhhhh, Metric system!
According to your answers,I conclude that there must be a max range for the squirt gun.That means,you can not increase the range by increase the pressure if it goes to the max range.
I think the question needs to be directed to a Physics Professor! From a practical point of view as a pump operator, I know that for a given combination of hose diameter, hose length and branch (nozzle to North Americans) increasing the pressure at the pump will increase the throw - the distance the water will travel. But I've never thought it to be in direct proportion, what the exact relationship is I have no idea. At a certain point, increasing pressure will have no further effect on distance.

I now wait to be proven wrong...
The only thing I know is you pull the trigger and water comes out. Sorry
These are some data of this test.
pressure----Distance
0.2MPA----20M
0.4MPA----25M
0.6MPA----30M
0.8MPA----30M
1.0MPA----30M
1.2MPA----35M
I can not continue because the hose may be broken.The hose is "13 Type 65mm/20M" which is 7.5kg.
You have me interested Jimmy. I can follow your test data, but what is a 'squirt gun' and what is '13' type hose?
As I originally said, your stream will break up once it reaches its maximum range with the maximum PSI before the stream breaks up. Therefore the inside diameter of the nozzle tip orifice have a direct relation.

If a smooth bore tip on a deck gun is perfect at lets say 110psi and it reaches 200'. Now by increasing the PSI doesn't mean that the reach will get any further. Take out an engine with a deck gun and try it. The stream will get broken and the reach will not get greater...

I can't explain your sudden 35M at 1.2mpa possibly wind?
Tony,there are many kinds of hose:type 13、type16、type 20、type 30、type 40；For example,hose type 13 means:Length 20m,caliber 65mm,weight 7.5Kg,working pressure 13Mpa.As you can see,"13" is its "working pressure".And its breaking strenth is 1.6Mpa.Type 40 is the most powerful hose with the working strenth of 4Mpa.But it is too heavy.About 20Kg.Caliber is 80mm(8cm).
Mr FETC,is the deck gun a very big squirt gun?Perhaps you reffered the fixed gun on the top of the truck.We called it "Water cannon".Good idea!I will retry this test by a deck gun when the weather turns to be fine.Perhaps 1.2Mpa 35M is caused by wind.But I am not sure.I will retry someday.
Thanks Jimmy. Our 64mm short lengths will be close enough. You've said that your water cannon (North American Deck Gun, Roof Monitor here) is a very big squirt gun? So is 'squirt gun' simply your name for the thing on the end of a hose that is used to direct a stream of water? And are they straight jet or adjustable?

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