Hard pipe vs flexible tubing... does it make a difference?

[mikeross]

I'm setting up a room with 3 rolling tables. I plan to build a manifold out of PVC which will tee off to feed each table. On the tables it will be all flexible lines. My main feed line going to the manifold is 30' away from my res.

Does it make a difference if this mainline is hard pipe or flexible tubing. Its a high PSI setup being feed by a leader pump. If it doesn't make a difference, it'd make the install easier just running a hose. Just wondering what the benefits of hard piping all your mainlines provides. thanks

 

[f-e]

A fixed hardpipe is nice, if it makes disconnecting a table, a one handed job.
You can probably do that with flexi's and ties though. I don't imagine you are talking iron. Just PVC.

I really like garden hose and all the attachments you can buy for pennies. They just screw on. Most aimed at irrigation use. I can guaranty my local garden supplies store will have a huge range of such things, and absolutely no hardpipe.

Hardpipe is for permanent installations. Or where hose might age prematurely. The reusable nature of garden stuff can save a lot of bother over the years.


30 foot is some distance. Many liters. You might want to think about a method of purging. Personally, I'm opening the end (as a return to the tank) for a few seconds, when the pump starts.

 

[alpo]

flexible PVC pipe moves when given pressure.

 

[mikeross]

A fixed hardpipe is nice, if it makes disconnecting a table, a one handed job.
You can probably do that with flexi's and ties though. I don't imagine you are talking iron. Just PVC.

I really like garden hose and all the attachments you can buy for pennies. They just screw on. Most aimed at irrigation use. I can guaranty my local garden supplies store will have a huge range of such things, and absolutely no hardpipe.

Hardpipe is for permanent installations. Or where hose might age prematurely. The reusable nature of garden stuff can save a lot of bother over the years.


30 foot is some distance. Many liters. You might want to think about a method of purging. Personally, I'm opening the end (as a return to the tank) for a few seconds, when the pump starts.

The way I have it setup, each table will have a air relief valve and also a shutoff valve. At each irrigation the air relief will allow a little water to spill out the end of each line until PSI is over 25psi in the lines than seals up. After this relief valve I also have a shut off valve. Weekly between res changes I will fill up the rez with plain water, open the shut off valve and drain the res/flush out my lines.

 

[f-e]

25psi. I could get lost in my thoughts about such a thing.

Interesting relief valve. I couldn't really find anything. So I have a solenoid there. It's not wired yet, but will run with the pump, through a duration timer. So it's only open a few seconds, each time the pump runs.

 

[mikeross]

25psi. I could get lost in my thoughts about such a thing.

Interesting relief valve. I couldn't really find anything. So I have a solenoid there. It's not wired yet, but will run with the pump, through a duration timer. So it's only open a few seconds, each time the pump runs.

https://www.irrigationdirect.ca/Installation-of-Air-Relief-Valves-for-Drip-Irrigation-Systems.html

"The Air Release Valve is often overlooked but is a valuable component for maintaining a sub-surface drip irrigation system. The air release valve allows air to escape the system on it's initial start up until the system is full of water. Once full the valve automatically closes until the cycle is finished and then allows air to flow back into the system. The air release valve helps in avoiding clogging of emitters due to back suction and will extend the long term life of the system. It also helps to avoid water hammer at the start of a watering cycle."

 

[CrushnYuba]

Man.. After using a ton of poly pipe.. That shit always leaks a little. Pvc that is glued does not. Anything that uses a clamp and barb or whatever does. Garden hose is only 3/4" or 5/8

 

[LostTribe]

I'm setting up a room with 3 rolling tables. I plan to build a manifold out of PVC which will tee off to feed each table. On the tables it will be all flexible lines. My main feed line going to the manifold is 30' away from my res.

Does it make a difference if this mainline is hard pipe or flexible tubing. Its a high PSI setup being feed by a leader pump. If it doesn't make a difference, it'd make the install easier just running a hose. Just wondering what the benefits of hard piping all your mainlines provides. thanks

Use a combination of both hard and tubing. Tubing for when you need it to be mobile.

 

[f-e]

https://www.irrigationdirect.ca/Inst...n-Systems.html

"The Air Release Valve is often overlooked but is a valuable component for maintaining a sub-surface drip irrigation system. The air release valve allows air to escape the system on it's initial start up until the system is full of water. Once full the valve automatically closes until the cycle is finished and then allows air to flow back into the system. The air release valve helps in avoiding clogging of emitters due to back suction and will extend the long term life of the system. It also helps to avoid water hammer at the start of a watering cycle."

It's just a ball isn't it? It floats up and blocks the hole.
I guess you will be using PC drippers. Perhaps the self cleaning ones, that really open up when the pressure is low? So that the lines can empty quickly, with some hint of decent distribution.
I wonder if another valve would be useful. One to drain the manifold at low level. So all the emitters suck in air. Rather than some drip for hours.



1/2" hose will run a couple of hundred emitters.
Here we have 100 foot of hose, of different widths, used at different pressures.
https://www.engineeringtoolbox.com/water-discharge-hose-d_1524.html
With HPDS type pressures, 1/2inch can deliver 5 gallons per minute.
Hang about. 5 gallons per minute. I contest my own data. I have shit faster than my hose(excuse me).

Another link https://www.new-line.com/information/flow-capacities-of-hose-assemblies
It agrees. 300 gallons per hour.

Looking at that picture, we have ~20psi pushing water into 100 foot of hose. Some pressure will be lost along the length of the hose. At the 50 foot mark, half the pressure loss might of occurred. Leaving at least 10psi for some PC emitters. With 150 gallons per hour of flow.
With two hoses forming equal pressure manifolds, this capacity is doubled.

If you want to empty a water butt in 15 minutes, a half inch hose will do it. I have used a straight run with 60 2L per hour emitters. Only 30 gallows per hour, but there was no pressure drop at all. With non PC (arrow) emitters all flowing 33cc a minute. That puts 120 emitters on a 1/2" loop, not even pushing the envelope.

1/2" is quite big. So are some operations







I don't like the black 'thin wall' PP looking hose. It has no elasticity. If you turn a barbed fitting a few times, the pipe becomes a leaky socket. So you have to get your lighter on it, to shrink it. I have not had garden hose leak, using simple barbed parts. For many drains, I have drilled a 12mm hole in a container, and forced the 1/2" hose tight into the holes. Bucket after bucket. No leaks, though that 12mm hole must be smooth. I really like garden hose. It doesn't look out of place in the bin either. A concern with any purchase.

Wrote yesterday.. fell to sleep without posting..

 

[mikeross]

f-e At the end of each table will be a ball valve, PSI gauge and pressure relief valve. I size my reservoirs to last a week. When its time for a rez change I plan to top up the rez about 20% with plain water, open the ball valve at each table and flush the entire system. I run Jack's, very clean nutes and plan to run a mesh filter off the pump and a mesh filter for each table. I also run drip clean and will do a real flush/cleaning between runs.

I will be using a 1/2hp leader pump to feed 288 .5gph emitters over 144 plants. It sounds like a lot of emitters on one zone but going off the specs of the pump, the pump should handle that load no problem.

 

[mikeross]

This is the pump I plan to use... https://www.leaderpumpshop.com/Produ...coJet-120.aspx

I don't know if I am calculating it correctly but if I am running (288) 0.5gpH PC emitters I need a pump that can create 20+ psi with minimum 2.4gpM. The specs on the pump in the link suggest this won't be a problem.

I'm only second guessing myself because I see people running separate zones using solenoids/timers with less plants all off the same res. Any reason why people do this if the pump can handle the entire room on a single zone. I just don't get why you would create separate zones using solenoids, as the solenoids are prone to failing over time. Why not run a single zone if the pump can handle the load... what am I missing here??

 

[Raho]

This is the pump I plan to use... https://www.leaderpumpshop.com/Produ...coJet-120.aspx

I don't know if I am calculating it correctly but if I am running (288) 0.5gpH PC emitters I need a pump that can create 20+ psi with minimum 2.4gpM. The specs on the pump in the link suggest this won't be a problem.

I'm only second guessing myself because I see people running separate zones using solenoids/timers with less plants all off the same res. Any reason why people do this if the pump can handle the entire room on a single zone. I just don't get why you would create separate zones using solenoids, as the solenoids are prone to failing over time. Why not run a single zone if the pump can handle the load... what am I missing here??

One reason people might do this is because they are not mono-cropping a cutting.
Maybe they are running big plants in big pots in one zone and small plants in another.
Each zone can have a different duration of feed while still sharing the same pump and most of the same plumbing.

 

[f-e]

Odd pump. Says it's 1/2HP. Says it's 3/4HP. Says it's 1.5HP. All within a few words. I can't believe a word it says. However, if the graph is right, which is statistically unlikely, you might see 50psi. That can overwhelm some emitters. You should think about a PRV to allow excess back to the tank. At 50psi I have seen plenty of push fit connections let go. It's a bit much.

Most folks choose a bad pump. Then they start zoning to fix the symptoms. The pressure aspect is lost upon them. They just size pumps by the gallon. Going bigger and bigger until it works. There are many hydroponics outlets that don't know any better. Very few stock the right kit. Very few indeed. You are miles ahead of the pack here.

Do your PC emitters need 20psi? 15psi is a much more common pressure. Butt pumps can manage that. It's their job to irrigate from a butt. Growers often choose them as they take up no further floor space, and run quieter. I saw a jet pump in a factory that had building blocks around it, to keep the noise down. The DB rating is sadly missing in the link.

I failed to find a cost effective PRV that had a reasonable bore. There are quite a few 2-port 3-Bar adjustable ones, but it's only down to 2.5-Bar usually. Brass stuff. Safety valves. For boilers. Such a thing would offer some relief though. Capping the pressure at 2.5 and using the excess to stir the tank.

 

[Drewsif]

1.5hp root mean square. It means your pump is 1/2 hp and marketed to poor people.