Discussion forum for the various methods and structures used for getting an early start on your growing season, extending it for several weeks or even year 'round.
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March 10, 2017 | #1 |
Tomatovillian™
Join Date: Jun 2013
Location: Wasilla Alaska
Posts: 2,010
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Greenhouse irrigation pumps
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. |
March 10, 2017 | #2 |
Tomatovillian™
Join Date: Jun 2012
Location: Illinois, zone 6
Posts: 8,407
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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. |
March 10, 2017 | #3 | |
Tomatovillian™
Join Date: Jun 2013
Location: Wasilla Alaska
Posts: 2,010
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Quote:
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March 10, 2017 | #4 |
Tomatovillian™
Join Date: Jun 2012
Location: Illinois, zone 6
Posts: 8,407
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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. |
March 10, 2017 | #5 |
Tomatovillian™
Join Date: Jun 2013
Location: Wasilla Alaska
Posts: 2,010
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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. |
March 10, 2017 | #6 |
Tomatovillian™
Join Date: Jun 2012
Location: Illinois, zone 6
Posts: 8,407
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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. |
March 10, 2017 | #7 |
Tomatovillian™
Join Date: Jun 2013
Location: Wasilla Alaska
Posts: 2,010
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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.
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March 10, 2017 | #8 |
Tomatovillian™
Join Date: Mar 2015
Location: Kennewick, WA (7a)
Posts: 182
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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.
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March 10, 2017 | #9 |
Tomatovillian™
Join Date: Jun 2012
Location: Illinois, zone 6
Posts: 8,407
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It would be easier to just switch to aeroponics.
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March 10, 2017 | #10 | |
Tomatovillian™
Join Date: Jun 2013
Location: Wasilla Alaska
Posts: 2,010
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Quote:
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. |
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March 10, 2017 | #11 | |
Tomatovillian™
Join Date: Feb 2006
Location: Den of Drunken Fools
Posts: 38,539
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Quote:
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 |
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March 10, 2017 | #12 |
Tomatovillian™
Join Date: Feb 2006
Location: Den of Drunken Fools
Posts: 38,539
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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. Last edited by Worth1; March 10, 2017 at 09:51 PM. |
March 10, 2017 | #13 |
Tomatovillian™
Join Date: May 2012
Location: massachusetts
Posts: 1,710
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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 |
March 10, 2017 | #14 | |
Tomatovillian™
Join Date: Mar 2015
Location: Kennewick, WA (7a)
Posts: 182
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Quote:
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. |
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March 10, 2017 | #15 | |
Tomatovillian™
Join Date: Jun 2013
Location: Wasilla Alaska
Posts: 2,010
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Quote:
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. Last edited by AKmark; March 10, 2017 at 11:16 PM. |
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