DIY Misting Pump Ideas?

You might be able to feed the output of one pump to the inlet of another, but you need to be mindful of capacities. If I was to do that, I'd want a slightly higher capacity pump feeding the lower capacity pump.

For gravity to be effective, you'd need a really high water column. Remember, it's the height of the column that counts, not the overall volume.

 

Probably not. A pump can only add so much pressure to a line, so to speak. If you run them one after another, each may only be adding 20 psi to the line, but the total is 40. Two pumps side-by-side will still only boost pressure by 20 psi.

Think of it this way: Each pump is like a battery, say a AA alkaline. If you put one battery after another, you get 1.5v increase for each battery - that's a series connection. If you connect them in parallel, you still only have 1.5v, but you can get more current (that's the equivalent of the water in this example) flowing.

For misting, you need pressure, not flow, at least not unless you have too many nozzles in your loop.

 

Cheap, easy, reliable - choose any two.

I use a misting pump that puts out 150psi, and some matching nozzles. Cost was around $300. You can get a shallow well pump, which has a pump and reservoir connected to it, that'll put out enough for misting, you hook the pump inlet to your water reservoir, and let gravity feed it. Expect to spend around $150 at Harbor Freight.

For a small volume, you can try an ultrasonic humidifier. I had one that I hooked up to a 2x8x2 cabinet, filled it with fog. Use DI or R/O water if you don't want white leaves. Just shop the sales, because under continuous use, they don't last that long. For a smaller space, a Reptifogger from Zoomed might work for you. Comes with a flexible outlet tube, so you can duct the mist into your environment. For bigger spaces, there was some discussion about the ultrasonics from House of Hydro. You might want to consider that.

 

Here is how you go cheap...
Pump
Power Supply (or just find a 12 volt at least 3 amp power supply from an old laptop or something)
Mister Heads - You can find these at a hydroponics store if you have one locally.

Then just plumb it up. Won't be everything a mistking is, but will work great, and for under $40 your best option in my opinion. You can get cheaper pumps, but they usually aren't self priming which means your water needs to sit above your pump which makes things a pain. You want at least 45psi to run the drip irrigation mister heads. Anything will low pressure won't work for you. Don't hesitate to ask any questions.

 

PSI of a pump is given in it's specs - it's usually listed as the pump's "head" - i.e. 10ft of head, meaning it can pump against a 10 foot column of water. You calculate pressure from there. A 1 sq. inch column of water 10 feet high weights so much, so those pounds/square foot tells you psi. A 1 sq. inch column of water 231 (about a gallon) inches tall (almost 20 feet of head) corresponds to about 8 psi.

For fluid flow, just like electronics, pressure, flow, and resistance are all proportional - just like Ohm's law relates voltage, current and resistance - V = IR. So, you need more pressure to move a given quantity of water through a smaller pipe network. To calculate that, you need some data about flow rates through your networks. But anyway, a pump's specs generally tell you flow rate per foot of head, and will often give you a graph.

So as Gregg Z says, you want at least 45psi, so that's a 45lb column of water, or about 6 gallons, so about 120 feet of head.

(I'm an electrical engineering student, not mechanical or chemical engineering, although I did play one 40 years ago, so I may not have everything right.)

 

Jai, I don't know what a "day pump" is. Can you provide a link? The key is pressure. A low pressure pump can move A TON of water, but may only drip out of a misting head. I think what you are wanting to do is spray a mist to water your plants. if that is the case, the volume of water the pump can move, how far it can move it, or CC's, doesn't matter.

For a 4' by 4' cube, you are probably going to want maybe 6-10 misting heads.

 

Very cool, thanks for sharing the video. I may have to try that one day. I don't think that would get you what you want. I doubt that would produce much pressure. And I am not sure it would be much cheaper.

You can also use a car window washer pump and save a few more dollars, but they are much noisier and you need to run them in shorter bursts. It isn't a good idea to run one for a minute at a time. So you need a timer that runs in seconds not minutes, and those are a little more expensive.

 

You had better come up with the spec for the nozzles first.

 

Which require "x psi" to. Work.