Water Display - Page 1
Forum section: electronics / projects

author: botcrusher
author_rank: Regular Contributor
timestamp: August 13, 2016, 07:11:37 pm
content: Thanks to the Cirque Du Soleil, I've been thinking up as cheap a system as possible.The idea in question is to use a row of solenoids connected to a closed loop (err, open to air, but you get the idea) water system which catches the water and pumps it back up.Wondering about parts / execution.The concept seems simple enough, I can shift register relays to control the solenoids, timing will all be done through DMX.But the actual specs for the water is what gets me.If i can pump it to the top to a holding tank, i can probably get gravity to do the rest, but what about that pump? Wth do i do for that!

author: Kilrah
author_rank: Unknown
timestamp: August 13, 2016, 07:26:23 pm
content: Quote from: botcrusher on August 13, 2016, 07:11:37 pmUh, you fill the tank?What's the question?

author: kolbep
author_rank: Frequent Contributor
timestamp: August 13, 2016, 07:28:22 pm
content: I was also interested in building something up (saw the LaserX videos about the 'water printer' as they call it).But the only solenoids I have really been exposed to are the Washing Machine inlet solenoiods, and the Irrigation Solenoids.IIRC, they both need to have pressure behind them to open? Do they then have the system pressurised, or what solenoids do they use that can open/close, but just have normal gravity flow?P

author: Kilrah
author_rank: Unknown
timestamp: August 13, 2016, 07:39:21 pm
content: I would think the systems are pressurized, wouldn't get enough flow with gravity. Pump in the sump, pipe goes up to the ramp of solenoids, at the other end of the ramp you've got a pressure valve and a pipe that goes back down to the sump. Gives you a constant pressure to work with, same as fuel and oil systems in engines.

author: Fungus
author_rank: Super Contributor
timestamp: August 13, 2016, 07:44:10 pm
content: Quote from: botcrusher on August 13, 2016, 07:11:37 pmUm, buy a pump?http://www.ebay.com/sch/i.html?_nkw=water+pump

author: botcrusher
author_rank: Regular Contributor
timestamp: August 13, 2016, 09:35:46 pm
content: Clearly. xDWhat I should have specified was what kind of flow rate, Mpa rating, Etc.My phone was running out of juice, and i wanted to get the post in.Please Keep in mind the intended application for this is indoors, In an auditorium Designed to project sound towards the crowd. (I'll deal with the part involving not soaking everything) It is preferable for the pump to not be obscenely loud.

author: promacjoe
author_rank: Regular Contributor
timestamp: August 13, 2016, 09:39:41 pm
content: Quote from: Kilrah on August 13, 2016, 07:39:21 pmhow do you think hydroelectric plants work, or in fact your municipal water system. The pressure is maintained by gravity. 1 in.³ of water = 1 ounce liquid = 1 ounce in weight. Stack 16 ounces of water on top of each other and you will get 1 pound of pressure at the bottom of the stack. at 133.3 feet, you will get 100 psi at the bottom. Granted, I doubt that it would be feasible to do this, But that's the way fountains have been powered for thousands of years, before the advent of pumps. you cannot compress water, so you must maintain water pressure by either controlling the height of the tower, By brute force of the pump, (not very stable) or by a bladder tank. A bladder tank has water on one side and air pressure on the other separated with a bladder. The pressure is maintained by the bladder not the water or pump, acting like a capacitor for water. The water pressure depends on how much air pressure you have on the other side of the bladder.without knowing exactly what his needs are, volume/pressure, It will be difficult to give any advice at all

author: Kilrah
author_rank: Unknown
timestamp: August 13, 2016, 09:45:53 pm
content: Quote from: promacjoe on August 13, 2016, 09:39:41 pmWith a lot of height difference you can typically not have in such an installation. None of those I've seen did, a big tank 10m or so above the installation is usually not practical, and would also not satisfy the typical "visual design" requirements. The thing has to be easily mobile, fit in low ceiling venues, and look good.

author: botcrusher
author_rank: Regular Contributor
timestamp: August 13, 2016, 09:50:51 pm
content: For pressure needs, I need to be able to pump the water back up to at least 4m off the ground.It would be nice to have more room for adding solenoids when practical, but the base system would be running 8 Solenoids that can have enough flow to make pulses of water. I don't need copious amount of water in the system, just enough to keep everything going without interruption.The majority of the water in waiting can be at floor level, where the water is "received"The spraying part of the system needs to be hung on a fly gallery bar.The very poor man's version of this:https://youtu.be/vKKpxIhx72I?t=87

author: promacjoe
author_rank: Regular Contributor
timestamp: August 13, 2016, 10:12:15 pm
content: The problem is not so much pressure, but volume and maintaining that volume/pressure regardless of how much and when water will be released. The water tank at 4 m in height that was indicated would not be difficult and a overflow pipe might be needed to maintain constant volume in the tank when all the solenoid valves are turned off. The major problem is controlling the flow of water. That will require some Careful thought and experimentation.

author: GBowes
author_rank: Contributor
timestamp: August 13, 2016, 11:00:39 pm
content: Quote from: promacjoe on August 13, 2016, 09:39:41 pmWouldn't it be great if this were true? Then there would be no justification to change to metric.Actually, 1 US fluid oz has a volume of 0.554 in^3 and a mass of 0.32 ounces.The point in your post, of course, is still valid.

author: SL4P
author_rank: Super Contributor
timestamp: August 14, 2016, 12:56:51 am
content: I'd also be considering how to ensure equal pressure across all valves during all modes of operation at peak firing rate...What's the difference if you open everyfourthvalve /vs/ opening fouradjacentvalves every 100mS?I think pumping up 4m is the easy part.

author: dmills
author_rank: Super Contributor
timestamp: August 14, 2016, 03:21:36 pm
content: Personally I would go for a non positive displacement pump stack feeding the manifold directly, a modest stack of centrifugal stages can generate a good few bar of pressure (Which is much more then your header tank based system will), cold water booster sets are an off the shelf thing and often include a modest tank with air bladder to stabilize the pressure.https://www.machinemart.co.uk/p/cbm250ss-1in-stainless-steel-booster-pum/at the low end of the market up to MUCH larger plants at the top end made by folks like Gundfoss pumps.You will want to at least consider the effects of water hammer if you have a long pipe between the pump and the valve gear.Regards, Dan.

author: SeanB
author_rank: Super Contributor
timestamp: August 14, 2016, 06:09:29 pm
content: Simplest cheap method is to use a pond pump, which is submersible, reasonably quiet and which even is available in 12VDC versions. This feeds up to the manifold on the top, and your water valves are connected to this. The manifold is a larger diameter pipe, and at the far end you put a pressure regulator to keep a constant pressure. Valves will need to be small, and have a nozzle on the end to get the flow, but also need to have a minimal volume ( but they do not need a high flow rate) and need to be direct acting.You can get away for a short term project using pneumatic valves, as they will survive water for a while, though they will corrode.

author: ez24
author_rank: Super Contributor
timestamp: August 14, 2016, 06:59:16 pm
content: OP - if you can work outside, you might want to use a garden hose and garden hose regulator and work on the solenoids first. Once you get them working then you could work on pumps so you can move the work. This way you could split up the work load.And if me, just for the hell of it, I would try and contact the engineers at the companies who make the irrigation valves. My gut feeling is they will not work but I do not know why. Maybe their "lag". The engineers may know how to size or pressure them for your application. Sometimes company engineers really get into odd things (I think because they are bored). The challenge is how to get to talk to them. Start by asking everyone you would like to talk to an engineer, sometimes it works. Depends on your people skills.

author: Twoflower
author_rank: Frequent Contributor
timestamp: August 14, 2016, 07:38:14 pm
content: Get a inkjet printer (sorry, I couldn't resist).I think you should first think about the size you want the drops to be. The next step would be the pulse-rate you need (vertical resolution).If I look to the Videos I think you need damn fast solenoids to get a reasonable resolution. The initial speed of the droplets hereis not that high, but you can see how short the time is until the drops are at the end of the display. If you have the solenoids that match this requirement (volume and speed) you can check the datasheet to check for the requirements they have for the water supply.

author: ez24
author_rank: Super Contributor
timestamp: August 14, 2016, 08:56:15 pm
content: Here is another viewIt spells out "Osaka Station City" - leave it up to the Japanese to come up with something like thisMy guess is that there are no off the shelf solenoids that can do this. Hope someone can post some pics of them.Nice video - thanks

author: ez24
author_rank: Super Contributor
timestamp: August 14, 2016, 08:57:20 pm
content: Here is another viewIt spells out "Osaka Station City" - leave it up to the Japanese to come up with something like thisMy guess is that there are no off the shelf solenoids that can do this. Hope someone can post some pics of them.Nice video - thanksFYIhttp://www.cnet.com/news/osaka-station-fountain-displays-time-art-in-water/

author: Twoflower
author_rank: Frequent Contributor
timestamp: August 15, 2016, 04:38:45 pm
content: Because the idea is quiet nice and I wanted to see how they did this in Osaka. I stumbled over this video:He mentioned in the comments section of his channel (not the comments below the video) he used SMC valves. Comparing the design of the valves are the old version of the VDW type. The datasheet says nothing about the speed they can be operated. In another video someone mentioned open in 20ms. That seems to be a reasonable speed you need to archiveAnd he seems to feed it from the water-faucet. So no need for high pressure/high volume.

author: botcrusher
author_rank: Regular Contributor
timestamp: August 15, 2016, 06:17:32 pm
content: Hmm. I'll look more into those valves!My school is "eco certified" in our province, so using only water mains would be rather frowned upon

author: Twoflower
author_rank: Frequent Contributor
timestamp: August 15, 2016, 06:53:43 pm
content: I fully agree with not using water from the faucet all time**. It's more useful to build up a water-circle with a pump. But that gives you an indication of the pressure and volume your display might need.Maybe you can use some cheap industrial type valves as the ones from SMC might be a bit expensive. As you need several of them. But it seems none of the ones I checked provide the response time.That could be a fun project. Please keep us updated.---** Here in Germany actually the people learned to safe water to well (no pun intended). In some places they need to open the hydrants to make sure that the water in the pipes are not stale and/or the sewage pipes don't clutter. The reason is that they're designed for higher throughput than it is now with all the water saving.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 15, 2016, 07:33:13 pm
content: Valve speed is a big issue. Irrigation valves are very slow. It varies a lot from valve to valve and with other variables and is not controlled at all since that industry doesn't care about speed. Turn on time is measured in seconds, turn off is far slower. One place you might look is fuel injection valves. They are quite fast, but low volume, and may depend on the lubricity and corrosion properties of the fuel so wouldn't work on water.Flow rate will come from your visual design. Simple physics - diameter of stream and velocity of flow. I don't know if you are planning a falling water approach or a vertical jet. In both cases you have a trade between pattern distortion and pattern flow. The pattern will distort as velocity changes due to gravity. If initial velocity is high the distortion due to gravity will be low, but the pattern will move down (or up) your display very fast.Have fun!

author: botcrusher
author_rank: Regular Contributor
timestamp: August 15, 2016, 07:53:43 pm
content: I wonder if i could speed up the valves by forcing them closed with reverse polarity, or applying slightly higher than the rated voltage in either instance of polarity.So as to not overheat it, would generating some kind of short higher voltage pulse followed by the rated voltage to sustain work?This is just me getting creative ideas, i won't do anything other than the pump and solenoids like that unless i have to!Falling water is the approach. Though thinking of it, the vertical jet approach could be very cool. Another project for another time.

author: Twoflower
author_rank: Frequent Contributor
timestamp: August 15, 2016, 07:57:41 pm
content: Quote from: CatalinaWOW on August 15, 2016, 07:33:13 pmI think you refer to the kind of valves for high volume. They use motors to open/close. Or some use electrical heated wax cartridges (response time minutes). I'm talking more about valves used for hydraulics, they seem to be able to operate also in the two digit Hz rate. Ssearch for "High speed valve operation", I don't want to link to another YT-Video, to hear one valve operated at up to 140Hz.The fuel injection valves might not provide enough throughput and probably due to the high pressure the droplets will just burst into fog.

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 15, 2016, 08:07:33 pm
content: I googled "high speed fluid valve" and found this:http://www.smcworld.com/products/en/s.do?ca_id=526&se_id=1982&show_page=true#detail

author: ez24
author_rank: Super Contributor
timestamp: August 16, 2016, 01:35:50 am
content: Quote from: PA0PBZ on August 15, 2016, 08:07:33 pmthanksJust a quick look - I could not find any prices. Wonder if these are in the 100s or 1000s ?