Increasing water pressure for a sprinkler

Increasing the pipe dia will reduce the resistance to flow and hence the losses...
Thus it may increase the pressure and flow at the end of the pipe.
Surest way is increase the head or pump it.

At home one of our showers is gravity fed...a big bore showerhose did make a significant difference.

Del

"Is there a way to augment the pressure to say 15psi passively, ie without using a pump?"

Yes, raise the tank....or at least raise the level in the tank

"I intend reducing the piping from 1" to 1/2". Will this increase the pressure? No reducing the pipe size will not increase the pressure.

Del's idea of increasing the pipe size will reduce line loss, but it may not be enough to help much.

You will probably need to get a pump, that is likely to be the easiest and cheapest way to solve your problem.

Another solution would be to place the sprinkler at a lower elevation, thereby increasing the differential elevation (head) to the tank. 22' lower would give a static pressure of about 15 psi. You neglected to mention that a working sprinkler at the bottom of a 22' hole will not suit your needs. (27" water column = 1 psi approx)

Or you could pressurize the vapor space in the tank. If a compressor (pump) is not an option, a chemical reaction like sodium bicarbonate and water could be useful.

Del and Steve are correct about pipe size, smaller pipe means more pressure loss due to flow.

If my assumptions regarding your application are correct. My recommendation is to use another method to distribute the water, perhaps drip irrigation?

I like that Ace, like those Euro toilets, he just needs a small air compressor to pressurize the vapor space in the tank!

Hello all.

Spent the first 30 years of my life with no pressure system for water at our house. (Yep we lived way out in "the bush".)

Mum wanted sprinklers for the garden. It was a nice touch.

We found there are "low pressure" sprinklers available that will work at 5psi. They didn't have a big "throw" but performed well. (about 2m diameter got watered at a time.)

Later when we set up a pressure system, they still worked, just with a bigger spray radius.

There is a way, but it's not straightforward. You can use the low pressure water to drive a pump. e.g. Two coupled cylinders, diameters A and B:

This is the basic scheme: valve open - everything fills up, 'HP' out = LP in.

Valve closed: HP out = (^A/_B)² x LP in

Now fix up a few valves (mechanically switched) so that the system reverses at the end of the stroke, & ends up reciprocating & supplying lots of HP water (albeit at low flow rate).

This was the principle used in a damn great big pump I once had to control for water-jet cutting 6" steel plate. You could hear the reciprocating action (just, through the ear defenders).

A bit excessive for a sprinkler system, but it works!

Just an extra thought - you could probably use a turbine (driven from the LP source) to drive a pump to squirt the water. May be easier - cuts out a bit of valve gear.

Sorry, haven't done any sums on it. I suspect my 1^st suggestion would use less water, if it matters.

John.

If the number of sprinkler heads was cut in two and two separate "zones" were used. there might be enough of an increase to make the system workable. What would a single sprinkler head perform like?

It sounds to me like the best and most efficient way to raise the pressure in your circuit would be to pressurize the reservoir (holding tank). Just be very sure that reservoir can withstand pressurization. I would put a positive pressure of about 20PSI and be done with it. Depending on the volume of water you are using, just size a small compressor to stay up with your requirement.

thanks for all your comments and counsel. i am talking of a place where quality power is a premium or not available... quite apart from the fact i am trying to reinvent a simpler world. water is pumped up to a 12' high oht by a windpump. a way of intensifying the pressure is always useful around the place quite apart from driving the sprinkler.

thanks johnDG. something like what you suggest is what i was looking for. the differential piston intensifier can be very simple if i am trying to hike 5psi to say 25psi. it can be built from a standard thick wall pvc pipe with a plastic piston. now if only there was simple way to reciprocate without valves! surely there is way to use ports located strategically on the piston or the cylinder wall? or something with springs maybe?

specifically for a sprinkler, a micro turbine driving a sprayer suggested by johnDG is a very good idea provided the turbine tail water is led to a built-in 'sump' from where the sprayer sucks it up. could be a patentable product idea too.

"a micro turbine driving a sprayer ... could be a patentable product idea too"

Anyone on CR4 who could develop it into a useful product, particularly if it could be made cheaply available wherever in the world it is needed, is welcome to it.

Just don't let the Kris-Del™ consortium get anywhere near it!

I agree with all mentioned by my friends.

Only I like to add such a comment on the following sentenc, "This gives a pressure of about 5 psi":

The pressure due water column shall be 5 psi only in case of the friction loss in the pipe (pipe inlet or tank outlet, pipe itself & pipe outlet) is zero. But due to friction loss, the net pressure at the end of pipe shall be lower than 5 psi.

How about a smaller secondary tank at a greater height.
This could be topped up from the first tank by a small electric solar powered pump, with an overflow back to the main tank.
This may seem silly, but it solves the prob of draining and raising the first tank....

It rather depends on your proposed usage rate etc...

Slap me with a wet Haddock if this is too silly...

Del

Good Morning,

Perhaps you are looking for a hydraulic ram.

http://www.clemson.edu/irrig/equip/ram.htm

why don't you look at a drip system. It would work well at low psi and not waste water. they have different gph emitters, (ie .5 1.0 2.0 5.0)

With a few "pumps" in series one can have some serious irrigation going on with no energy requirements.

I have an idea. Forget about the irrigation - generate power with the high pressure and use a low head pump to recharge the tank. The irrigation can be done with the surplus power.

Cant you just raise the head tank?

wow, Just an Engineer! what an elegant solution, explained in such vivid detail too. brilliant ...and thanks

you have in fact responded to my other recent related query as well, though you were not aware of it: animal driven low pressure hydraulics

Oh yeah? Check out his idea there for letting grazing donkeys (heck cows could do the job, too) charge up batteries! We gotta get this guy's input more often, eh?!?