Drip system design ideas?

[Vintage1969]

Hello, I am redesigning a new drip system, I have used regular drip tubin, staked on either side of the plant. I have not tried any fancy sprayers/ emitters, Will be feeding from a reservoir into pots on two 4 x 8 trays. with two Magnum Xxxl hoods on each tray. Pump Used in past was regular sump pump with a filter.

 

[Vintage1969]

Growing in pots in coco

 

[queequeg152]

use a diaphragm pump... not a sump.

look at the pump curves of a diaphragm pump, and look at the pump curves of a sump or any centrifugal pump.

as a rule, positive displacement pumps tend to be near vertical... meaning they dont care much about the head they have to work against.

 

[sianhan]

Hi queenqueg very interested in getting a diaphragm pump and seen some on the bay that move 6ltr per min. But how do you connect them to a timer? The ones I have seen are 12v.

 

[queequeg152]

you can get a 110vac pump, but yes you are correct... most are 12v because most are used in mobile homes or boats or trucks for fuel transfer pumping...

you connect them to a timer in the same way you connect any pump to a timer.

you either use a relay or a 12vdc timer, or just directly switch the power supply from a simple wall timer unit.

i like the omron timers myself, but they are not ideal for weekly timers.

 

[sianhan]

To be honest this is a bit out of my depth but really want to give it a go.Queequeg can you run through the process of how we could use one of these pumps with a minute timer. I have a normal seconds and minute timer but will they work together.
Also in in UK and on 240v will it work with this or will I have to use a battery of some sort?

 

[queequeg152]

for 240v you simply need a 240v to 12vdc power supply... infact you might find that many 110vac power supplies can operate at 240vac 50hz by switching some dip switches.

i have a very expensive laser power supply that is able to do this.

what timing schedules are you trying to accomplish here? i cant teach you minor electronics, but i can suggest you a scheme to follow here..

 

[sianhan]

In soil. I only feed once every other day. In coco I do one per day only need the'pump on fir a few minutes really. Mainly do up to 20 plants in 15 ltr pots.
I'm into building computers so just thought I could use a old 800watt power supply?

 

[Vintage1969]

use a diaphragm pump... not a sump.

look at the pump curves of a diaphragm pump, and look at the pump curves of a sump or any centrifugal pump.

as a rule, positive displacement pumps tend to be near vertical... meaning they dont care much about the head they have to work against.

Hi, so I don't understand the difference between a sump, and a diaphragm pump. How would a diaphragm pump be better?

 

[queequeg152]

Hi, so I don't understand the difference between a sump, and a diaphragm pump. How would a diaphragm pump be better?

a diaphragm pump is a PD pump. PD pumps tend to perform well at very high heads.

your dripper system has a very high head.

i use a shurflow smart sensor pump. works extremely well.

here is an excerpt from a document i have.

1.2.8 Positive displacement pumps
The positive displacement pump provides an approximate
constant flow at fixed speed, despite changes in the
counterpressure. Two main types of positive displacement
pumps exist:
• Rotary pumps
• Reciprocating pumps
The difference in performance between a centrifugal
pump, a rotary pump and a reciprocating is illustrated
to the right, figure 1.2.18. Depending on which of these
pumps you are dealing with, a small change in the pump’s
counterpressure results in differences in the flow.
The flow of a centrifugal pump will change considerably,
the flow of a rotary pump will change a little, while the
flow of a reciprocating pump will hardly change at all.
But, why is there a difference between the pump curves
for reciprocating pumps and rotary pumps? The actual
seal face surface is larger for rotary pumps than for
reciprocating pumps. So, even though the two pumps are
designed with the same tolerances, the gap loss of the
rotary pump is larger.
The pumps are typically designed with the finest tolerances
possible to obtain the highest possible efficiency and
suction capability. However, in some cases, it is necessary
to increase the tolerances, for example when the pumps
have to handle highly viscous liquids, liquids containing
particles and liquids of high temperature.
Positive displacement pumps are pulsate, meaning that
their volume flow within a cycle is not constant.
The variation in flow and speed leads to pressure fluctuations
due to resistance in the pipe system and in valves.

 

[queequeg152]

In soil. I only feed once every other day. In coco I do one per day only need the'pump on fir a few minutes really. Mainly do up to 20 plants in 15 ltr pots.
I'm into building computers so just thought I could use a old 800watt power supply?

a computer psu ABSOLUTLY will work. it will work wonderfully, provided you have the amps on the 12v rail... keep in mind these units do not run when plugged in, you will need to jump a switch to keep them running.

ive also heard tell of psus failing when they are not under any load what so ever? like when they are just jumped and idling without any fans or HD's to power? i dont know why this would be the case, but you might want to look into this issue.

i payed like 80 bucks for my outdoor 400w PSU for my pump... if you can save that cash good going. i salute you.

regarding your irrigation schedule... i would reccomend( as i often do) a sprinkler irrigation timer... they are cheap and simple. get on ebay and pick one up for like 40 bucks.

you need a timer that has a "master valve" or pump relay. these timers will energize the pump or master relay when ever an irrigation cycle is called for.

these units run off of 24vac, so do the cheap yard sprinkler solenoids.
you will need a relay with a 24vac coil. when your irrigation timer sends power to this relay it will close a circuit that is powered by your computer power supply. closing this circuit will power your diaphragm pump.

its this simple.

if you dont know what a relay is or dont understand how they operate. please visit youtube. there will be visual explanations far clearer than i will ever be able to elucidate.

 

[queequeg152]

http://www.amazon.com/Dayton-1EHC8-Relay-24VAC-Volts/dp/B008596AN4

this is a relay. you will need a relay like this, and a socket to accept the relay.
this type of relay is way way more than you need...but its nice and slim and easy to conceal and easy to wire, you just need to crimp on some ring or spade connectors to get a real professional install.

wire this relay INSIDE of your irrigation timer if there is space.