Irrigation Line/ pump

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Nickeldeposit

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I’m setting up an automatic irrigation system to work with my hops this year. I want to feed water into one main line 1/2” or 3/4” x 80’ long w/ about 15 ¼” drip line off of it. Do you guys think/ know if this pump will work. One thing I thought of was will the pump get to much back pressure on it while it pumps? Also anyone know if it will hold back any pressure while off so I can leave my 100gallon tank valve open?

Wayne 115 Volt Transfer Pump — 310 GPH, Model# PC2
http://www.northerntool.com/shop/tools/product_200352045_200352045
 
That pump looks very similar to this 12v DC model from Harbor Freight:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=9576

The pump heads look identical. Anyway, the HF one is rated for intermittent use and it's very noisy. I have one. Back pressure shouldn't be a problem. I throttle mine back with a ball valve without issues. I don't think it will hold back any pressure or flow, but neither will any type of impeller driven centrifugal pump AFAIK.

Here's a pump that might be a better choice for your application:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=1479

Cheaper too and you can frequently find them for even less when HF has their weekly sales promotion.
 
One question I would have is where is your water tank situated? Since this is going to be a drip system, could you make it work just using gravity?

If you need a pump, the one you show may work but I might opt for something a little bigger and hook up a bladder tank with a pressure switch into the system. That way you could maintain the correct pressure that your drip system requires.
 
Are you planning on using emitters or just straight lines? Because even with 3 gph emitters, all of those pumps are way more than you'll need. If you are using emitters, you should regulate the pressure down to 15 psi.
 
There are alot of variables involved in this. What will be the head height of your drip lines, the GPH rating of your emitters, how many emitters, etc. not only do you need to know the GPH /GPM you need to know the pressure of the pump's output. If possible I would use gravity and a timer that can hook to a regular hose outlet available at your local blue/orange hardware store.
046878277298xl.jpg

Another thing to think about is the pump capable of having its output restricted. If its not a magnetic drive pump damage could result in restricting its output.
 
Another thing to think about is the pump capable of having its output restricted. If its not a magnetic drive pump damage could result in restricting its output.

This is one of the reasons I recommended adding a pressure switch and a bladder tank. The bladder tank can be small, I've seen two gallon tanks. The pressure switch will turn the pump off when you have reached the desired pressure, it has been suggested that 15 psi is what you need for your drip system, I don't know about that. The bladder tank acts like a "pressure reserve so you don't have your pump cycling on and off rapidly to maintain pressure.
 
Well here are some of the details. I'm going to use 1" poly tubing for my mainline (80' long run). I'll have 16 1/4" drip lines coming of the main with 2-3gph emitters or (none if that would work) connected to each. The 100 gallon water tank will be on a metal stand 2' off the ground with a valve near the bottom. The site I'm using has no water supply nor does it have power. So I'm using a solar charger+marine battery+power invertor+programable timer+pump=automatic watering system. I think I need to lay down about a gallon per watering. I'd like to see what kind of pumps use the bladder tank system. Also I'm not looking at dropping a few hundred on a pump. If you'd like more fact please ask away.

Looking for suggestions
 
Another thing to think about is the pump capable of having its output restricted. If its not a magnetic drive pump damage could result in restricting its output.

A total non-isssue. Any centrifugal pump can be throttled on the output, and magnetic drive has nothing to do with it. If you close the output valve on your March or Little Giant mag drive pump, the drive doesn't decouple. As a matter of fact, unless a part breaks or you get a foreign object in the volute, the drive never decouples.

The reason we use magnetic drive pumps is that there's no shaft seal to fail, which could possibly ruin a batch, but even that isn't likely. Typically when a shaft seal fails, it ust leaks - you'd lose a little wort, but that's it. Most commercial brewery pumps are not magnetic drive, their just all stainless and FDA approved.


OK, back to the OP. Given your lack of power or piped water, your approach with a DC pump, battery and timer seems like the best bet. Forget about the bladder tank - a small 12 volt pump will not pressurize it. Not to mention the expense. It would be cheaper to elevate your existing tank, and use gravity feed. Omit the emitters, reduce down to the smaller (3/32nd, IIRC) drip feeder tubes and leave them open, open the tank and time how long to run it. You might also consider the soaker hose, instead of drips.

Edidt: Add a standard solenoid sprinkler valve to your setup, connected to the timer and piped after the pump, then you can leave the 100 gallon tank valve open.
 
A total non-isssue. Any centrifugal pump can be throttled on the output, and magnetic drive has nothing to do with it. If you close the output valve on your March or Little Giant mag drive pump, the drive doesn't decouple. As a matter of fact, unless a part breaks or you get a foreign object in the volute, the drive never decouples.

You WILL burn that pump up or blow the lines. You dont want to throttle more than 50% if even that much. The reason magnetic drive pumps don't mechanically fail is that the motor does not get any stress on it due to pressure, the impeller is not attached straight to the shaft. You could run a return line to help with this. Personally I would use gravity and battery operated irrigation valve like i posted before.
 
I agree with weizen. Since your tank is two feet above the ground why not see if this alone provides enough pressure through gravity to use a soaker hose. Just hook up a timer to the hose similar to the one weizen posted to shut the flow off. They make simpler timers that need no power. I used to use one to top off a pool.

If this would work for you it would be an inexpensive solution.
 
A total non-isssue. Any centrifugal pump can be throttled on the output, and magnetic drive has nothing to do with it. If you close the output valve on your March or Little Giant mag drive pump, the drive doesn't decouple. As a matter of fact, unless a part breaks or you get a foreign object in the volute, the drive never decouples.

The reason we use magnetic drive pumps is that there's no shaft seal to fail, which could possibly ruin a batch, but even that isn't likely. Typically when a shaft seal fails, it ust leaks - you'd lose a little wort, but that's it. Most commercial brewery pumps are not magnetic drive, their just all stainless and FDA approved.


OK, back to the OP. Given your lack of power or piped water, your approach with a DC pump, battery and timer seems like the best bet. Forget about the bladder tank - a small 12 volt pump will not pressurize it. Not to mention the expense. It would be cheaper to elevate your existing tank, and use gravity feed. Omit the emitters, reduce down to the smaller (3/32nd, IIRC) drip feeder tubes and leave them open, open the tank and time how long to run it. You might also consider the soaker hose, instead of drips.

Edidt: Add a standard solenoid sprinkler valve to your setup, connected to the timer and piped after the pump, then you can leave the 100 gallon tank valve open.

Fletch, sorry bud but you have been misinformed. magnetic drives do slip. If the force of the line pressure is greater than the force in the magnetic couple the couple will slip. Close off the output and you will hear a march pump rev up.

Fixed drive centrifuge pumps should not be throttle using restriction. If placed on the input side it will cause cavitation, if it is on the output side and there is too much restriction the additional head pressure will create a greater load on the pump drive, thus drawing more current and heat. So you use more electricity and strain/damage the pump for less flow. Constant speed pumps are designed to work at a maximum line pressure and you do not want to exceed it. When a fixed speed/fixed shaft pump is used for industrial applications all of these things are taken into consideration. When throttling is needed, polyphase motors using VFDs are employed.

You could however put a bypass valve or pressure relief valve connecting the output to the input of the pump to allow access pressure to escape.
 
I don't want to get into a pissing contest, that is not my intention. I have designed a couple of water systems that were supplied by a submersible pump in a well and used a centrifugal pump to supply a pressurize the system.

Both Fletch and CodeRage are correct in a way. You CAN restrict the flow on the output side of a centrifugal pump. Doing this is like running a pipe from the output up a slope and creating a significant head. Pumps are rated for how much water they can pump at so many feet of head. Of course it is much better to not restrict the flow, but I have seen it done many times. Often a pump will have a 1" fitting bushed down to 3/4".

In the application we are talking about here - why restrict the flow? No reason to. A pressure relief valve could be used as CodeRage said. I have used these in larger systems only if I needed to have the pump continuously running. That is not the case here.

Once again. For this application, if pressure is needed greater than a gravity feed can supply, the best solution would be to add a bladder tank with a pressure shut off switch that shuts the pump off if it reaches the set pressure then turns it on again when the pressure drops. In a water system that supplies a home the shut off would be set around 50 - 60 psi, for shut off and around 40 psi for the pump to start again.

I still think that a gravity fed system will be all that is needed here.
 
Good luck with your system. Keep us updated.

I do have a question. I couldn't help wondering, how do you fill your tank?
 
Here are all the facts, design and components. Everything that needs to will be protected from weather inside the tank stand. I’ll be refilling the 100 gallon tank by hauling in water from 55 gallon tanks then pumping it. I plan to set up a test run this weekend to see the flaws before it’s needed to work all the time by itself. Let me know what you guys think.

SYSTEM DESIGN
http://img65.imageshack.us/img65/9702/watersystem.png

SOLAR PANEL
http://www.northerntool.com/shop/tools/product_200422047_200422047

MARINE BATTERY
No link, basic deep cycle from "W"


POWER INVERTER
http://www.northerntool.com/shop/tools/product_200365316_200365316

PROGRAMABLE TIMER
http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053

WATER PUMP
http://www.northerntool.com/shop/tools/product_200352045_200352045
 
Your system design jpg link doesn't work. Did you come up with a valve to keep the tank from draining by gravity?
 
OK, the link is fixed and i just took a look at your system. I have a few questions/comments.

1. If you are returning the water to the tank as you show in your diagram, how do you build up pressure for your emitters?

2. Your diagram show that in lieu of a valve you are running your supply pipe up above the water level in your tank. Since you will be supplying an line that is open because of your drip emitters what is to prevent a siphon effect from continuing to pull water from the tank?

3. Why go to the trouble of coveting your DC to AC via an inverter? You will loose a lot of power doing this. Why not just use a DC pump?
 
Sure, I’m not planning on using emitters just ¼” supply line staked in place. When the pump is turned off the impellor and pump body will be very restrictive killing any siphon effect that my happen going up the line. About the inverter, I really never found an inexpensive dc timer (locally). If you have any suggestions I still have my receipts LOL. The fewer components I need the better.
 
I would think about not using the inverter but I cant find a 12-Volt Timer to hook a dc pump into. Any help?
 
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