Greenhouse irrigation pumps

[AKmark]

I am looking for a continuous duty pump that is fit for drip systems. I currently have pumps and pressure tanks, but am looking for a consistent pressure. Does anyone understand pumps for this need? Or am I better off to use a pressure tank? Can you set the pressure on a CD pump?
I have looked at Dolphin pumps, but cannot find the info on pressure settings.

[Cole_Robbie]

A lot of pumps that produce pressure are made for high-pressure aeroponics, which is about 35 psi. At that pressure, when forced through a mister head, the mist will atomize, breaking into the smallest droplets that hang in the air for the longest time. Smaller systems use a small accumulator tank and a small pump. Larger systems have a big pump on a cycle timer, like a shallow well jet pump.

Do you know the psi you need? I doubt you need it as high as 35.

[AKmark]

Originally Posted by Cole_Robbie

A lot of pumps that produce pressure are made for high-pressure aeroponics, which is about 35 psi. At that pressure, when forced through a mister head, the mist will atomize, breaking into the smallest droplets that hang in the air for the longest time. Smaller systems use a small accumulator tank and a small pump. Larger systems have a big pump on a cycle timer, like a shallow well jet pump.

Do you know the psi you need? I doubt you need it as high as 35.

I want it above 30, my pressure regulators will check the pressure if it is higher. I can set my PT's to do that, but then I just use my switches too death.

[Cole_Robbie]

Your cheapest pump will be a shallow well pump from a Home Depot/Lowes type of store. They are about $200. They're not meant for irrigation, though, and the new ones have internal shutoff switches for when the pressure gets too high, due to flow being too low. To get around that issue, you can plumb a T into the line and place a pipe going back to the original tank with a valve. Open that valve a little to relieve pressure off the pump. Once you get it right, you shouldn't have to adjust it any more.

The advantage of using a big pump is that you can use plastic tanks, which are a lot cheaper. If you used a small pump and an accumulator tank, it would have to be made of metal in order to hold pressure, and thus would be a lot pricier. If you use a well pump, plan on it having its own dedicated 15 amp circuit.

Or just build a water tower A cheap sump pump will have up to 20' of lift. Once the water is in the air, you have pressure to tap, without having to charge the tank with a pump.

[AKmark]

What I have now is shallow well jet pumps from 1/2 horse to 1 horse, but they call for a pressure tank, which leaves a slight variable flow. What I want is a continuous duty that operates between 30-40 psi if possible. I just burned out a switch because the pump clicks off and on, even with 35 gallon pressure tanks.
I will read through your post carefully, maybe I can figure something out.

[Cole_Robbie]

That's what I'm talking about with the release valve plumbed back to the tank. It stops the clicking.

You don't need your irrigation to run constantly, if you just put it on a timer with short cycles. You can set the on time and off time to be whatever you want. If you do it that way, you don't have to hold pressure in a tank all the time, and it makes it all a lot cheaper. There are all kinds of cycle timers. The best ones look like a metal shoebox, with big metal mechanical gears inside, a couple hundred bucks. Cheap plastic ones tend to fail.

[AKmark]

My irrigation is on solenoids that feed back to a control box that has stations. It works good, but I am wanting to perfect the flow. I'll post a pic later of what I have, then maybe it will be easier to digest what I am asking. As usual, I appreciate any and all feedback.

[Rockandrollin]

Have you considered a variable frequency drive pump. Unless you exceed the capacity of the pump, it will hold a constant pressure that you set and will slow down or speed up to meet that goal. They are not cheap.

[Cole_Robbie]

It would be easier to just switch to aeroponics.

[AKmark]

Originally Posted by Rockandrollin

Have you considered a variable frequency drive pump. Unless you exceed the capacity of the pump, it will hold a constant pressure that you set and will slow down or speed up to meet that goal. They are not cheap.

That is what I want, yes. When the solenoid goes off I want the pump to maintain pressure until they go off. Maybe I used the wrong term by saying continuous duty. Do you have a page I can look at? I have been eyeing the Dolphin pumps, but cannot determine the PSI.
Here is the current set up, I am not sure if I can bypass the pressure tank with these cheapo pumps? I can run 572 drippers at once without outdoing the pump capacity.

I am not a pump guy, so like I said all ears.

[Rockandrollin]

Originally Posted by AKmark

That is what I want, yes. When the solenoid goes off I want the pump to maintain pressure until they go off. Maybe I used the wrong term by saying continuous duty. Do you have a page I can look at? I have been eyeing the Dolphin pumps, but cannot determine the PSI.
Here is the current set up, I am not sure if I can bypass the pressure tank with these cheapo pumps? I can run 572 drippers at once without outdoing the pump capacity.

I am not a pump guy, so like I said all ears.

Sorry, I am not a expert in this area. Your best best is your local pump person and google.

What I was referring to would replace your well pump and pressure control with a new pump and a variable frequency drive. They do require a pressure tank but are tiny compared to a conventional system, they are like 1 or 2 gallon.

They are becoming more common for residential well pumps. You mentioned you are in the 1/2hp to 1hp range which is a typical home pump size.

Their biggest benefits are having a constant pressure and much more economical to use. Your current well pump goes from 0 to full power in a second and the opposite when the pressure switch opens. These pumps are variable and ramp up down to maintain pressure and if need be will cycle off.

[Worth1]

Originally Posted by AKmark

I am looking for a continuous duty pump that is fit for drip systems. I currently have pumps and pressure tanks, but am looking for a consistent pressure. Does anyone understand pumps for this need? Or am I better off to use a pressure tank? Can you set the pressure on a CD pump?
I have looked at Dolphin pumps, but cannot find the info on pressure settings.

Yes they do and I went back to your original question to answer it.
The pump you are looking for is a centrifugal pump with an adjustable pressure relief valve that is piped back to the tank.
An alternative to the pressure relief valve would be a globe valve that you can open and close to adjust the pressure going to the field.
You want to make sure you dont boil the water coming out of the pump due to cavitation so this water has to go somewhere.
On the good side it can warm the water up for you.
Steps pick out pump.
Put valve on down stream side of pump.
Put gauge in line after pump.
Adjust valve by way of gauge reading.
DO NOT over estimate what pump sized you need bigger is not better.
This will only wear out the pump due to cavitation.
Your well pumps can keep the tank filled.
Worth

[Worth1]

What kind of controller is that if it is irrigation and you aren't maxed out you can get a pump start relay.
Or you can just connect it to the same zone as the valve for the drip system.
https://www.google.com/aclk?sa=l&ai=...QvhcIJg&adurl=
This is just an example.
Any relay that fires off of 25VAC and can handle you currant draw on the pump will work.

[Nematode]

Mark,
I've learned a thing or 2 about pumps, and have a couple products on the market based on pumps.
I see you want 30 psi, what gpm range do you want at that pressure?.
Should be able to hook you up with something.
Nematode

[AKmark]

Originally Posted by Nematode

Mark,
I've learned a thing or 2 about pumps, and have a couple products on the market based on pumps.
I see you want 30 psi, what gpm range do you want at that pressure?.
Should be able to hook you up with something.
Nematode

Awesome, I need at least 10GPM, I could get away with a bit less because I have an overkill with stations and solenoids. I have been looking at this for sometime, so anything can be helpful. I need somewhere between 30-40psi, not under 30 though.

I can use inline, or shallow well, unless you have a different idea.

Thanks everyone, when I get this dialed I will certainly share the info.