DIY dual peristaltic dosing pump with alternate switching.

Discussion in 'Completed DIY Projects' started by ian_m, 6 Jul 2012.

  1. ian_m

    ian_m Global Moderator Staff Member

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    Needed a solution to fert dosing whilst I am away for 3 weeks shortly (and as I keep forgetting). Time to make a gadget....

    Here is the finished item, awaiting to be fitted.
    DSCF5208.JPG
    And two one litre containers for the mixes.
    dscf5210a.jpg
    And inside.

    DSCF5215.JPG
    I got two peristaltic pumps from http://www.williamson-shop.co.uk/ for £42 each. Part number 101.015.230.030/4. 3rpm 4 roller (no back flow valve needed) giving about 3ml per minute. Also 5m of 4mm PVC pipe.

    Case part number 493-5786 from RS. Didn't want to get from RS (as might be trade only) but Maplin near me had zero stock of anything remotely useful.

    Switches 394-475 from RS. Any mains rated double pole double throw switch will do.

    Two computer IEC mains leads with IEC plug chopped off. Grommit & cable tie for cable.

    Suitable mains rated blue, brown and earth wire for internal wiring.

    Heatshrink and chocolate block.

    The connections for the switches are soldered and sleeved with heat shrink. The metal of the pumps is connected to earth from both leads.

    Here is the wiring diagram.
    Pump Box.jpg

    Operation
    The the switches allow either pump to be connected to either mains lead.

    Normally (in my case) the switches wil be down, selecting the "timer" mains lead, plugged into my timer. I will have timer set for 3 minutes every 24hours to give approx 9ml macro and micro.

    To prime the pumps, which considering their small capacity will take a while, push the switches up which connects them to the "power" mains lead. Once primed switch back to "timer"...job done.

    Also allows each pump to be run individually, one off each mains lead, if in the future I decide to dose say macro every two days interleaved with a different sized micro every two days.

    Made this tube holder out of a 32mm solvent weld 90 bend with a 14mm cut out. Plastic nut and bolts and couple of P-clips to hold tubes in place and prevent tube falling out.
    Pict9035.jpg

    Well here it is, wires out from back of box, both solutions piped in and back made for shelf to prevent the bottles falling out the back. Plenty of cable ties to hold pipes together and clamp pipes onto pump barbs. Also remember to drill a 1mm hole in bottle cap to allow air in. Takes ages to prime the pumps as 3ml/minute is not a lot and the pipe contains quite a volume of liquid in 1 metre odd. They also prime at different times due to different pipe length, so ability to have individual manual prime is handy.

    WP_20130415_001.jpg

    Here is what the outlet pipes look like 22 hours after last pump, absolutely no sign of it running back which has been a problem many people have encountered using cheaper 2 roller peristatic pumps..
    PICT9048.JPG

    I spent a while pumping water to "calibrate" the system and found I got about 30ml in 10 minutes, which matches the pump specification exactly (3ml per minute).

    My tank is 180l (say call 200l) and EI dosing is 10ml per 50l every other day, which is 40ml dose. Thus is 20ml a day.

    Thus to pump 20ml @ 3ml/minute I would need 6-7 minutes run time. As set on my Home Easy remote control, dosing couple of minute before lights off in the evening.



    -------------------------------UPDATE BELOW -----------------------------------

    Well here is an update with an alternate relay switching circuit that alternately switches power between the two pumps. When power is first applied it runs one pump and when power is next applied (next day for EI dosing) it runs the other pump. This means a single timer (& mains lead) may be used to alternately dose macro and micro.

    Below is the circuit I used.
    AlternateRelay.png

    And wired up to mains & pumps as below.
    Pump Box 2.png

    My version of the circuit made on some veroboard.
    Circuit.jpg

    The circuit is based around latching relay RL1, the state of contacts RL1C and RL1D being set or reset by coils RL1A and RL1B. As it is a latching relay it remembers its state over power cycles. Contacts RL1D are used to switch the mains to P2 or P3 connected to the macro and micro peristaltic pumps.

    Mains, from time switch, is connected via P1 to 12V transformer T1. P1 is supplied from the mains via a 250mA slow blow fuse. The 12V AC (actually about 15V as circuit doesn't really load the transformer that much) is rectified to DC via D1-D4 and smoothed by C1. Note C1 is purposely a small value as we don't require 100% smooth DC and also require the DC go away reasonably quickly once the mains is turned off.

    Once RL2 has sufficient voltage across the coil, its contacts RL2B and RL2B close connecting C2 or C3, via latching relay contact RL1C to the supply via D5 and current limiting resistor R1. Thus either C2 or C3 will get charged depending on the latched state of RL1C.

    When mains power is removed, by the time switch, the voltage across C1 quickly falls and relay RL2 opens, connecting the now charged C2 or C3 across the latching relay set (RL1A) or reset (RL1B) coils. Thus the capacitor discharges through the coil and switches over the latching relay, ready for when power is applied next via the time switch. D5 is necessary to stop C2 or C3 being discharged when the power is turned off.

    D6, D7 & D8 prevent and back EMF from the relay coils. They are not strictly necessary in this simple application as there are no delicate semiconductor devices that need protecting, but will provide an element of relay contact protection.

    The capacitors are generously over rated at 35V and 105C temperature, so should last millions of hours, epecially as they are only likely to be powered on for couple of minutes every 24hours. The LED's are not strictly necessary, but are/were handy to indicate the latched relay position whilst I built the circuit and tested it on a 12V power supply, rather than mains 240V. They can be just seen in my photo. In the finished box I connected the LED's to long wires and mounted them on the front of the box (where my original switches were). LED's, if used, must be 2mA low current LED's so as to not discharge C2 or C3 before they are applied to the relay coils.

    Below is the parts list. I got parts from RS (http://rswww.com) and Maplin (http://www.maplin.com) as both are near me in Southampton. RS also have the datasheets for the relay pin outs as well.
    Partlist.png

    When making, be careful as mains is being used, make sure a slow blow fuse is fitted. I removed all the underside copper tracking, where not used, on the mains connectivity bit, using a 4mm twist drill (by hand).

    I managed to mount the board in the bottom of the box, it was a bit tight as the transformer is quite large and rather limits the board placement between one of the pumps and reinforcing pillar in the box.

    If I was making it again I would make it on a much larger piece of board so I wouldn't have to cram all the components in and not have to have some on the underside of the board.

    And if I was making it again again I would use a simple microcontroller and single relay, and might be able to do away with mains transformer and do it all in the microcontroller software, but as I am not an expert on microcontrollers will leave for another day. :D

    Been using for a week or two now, works fine. Enjoy. :D
     
    Last edited: 29 Jan 2016
    zozo, rebel, banthaman.jm and 2 others like this.
  2. Aqua sobriquet

    Aqua sobriquet Member

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    Re: DIY dual peristaltic dosing pump.

    Very useful, thanks for posting.

    Next job is to hook up a PSP to a float switch and reservoir to automatically top up the tank while you're away! :D
     
  3. spill50

    spill50 Member

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    DIY dual peristaltic dosing pump.

    Love it I'm definitely gonna do this ;) thanks for posting this.
     
  4. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics.

    Updated with more pictures.
     
  5. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics.

    Still not complete....

    Had to attach a "back" to the internal Juwel shelf as its quite easy to push the bottles of ferts down the gap at the back :wideyed:

    Decided that having the mains wires coming out where they do is a pain in the bot. They tangle with pipes and containers. This is my fault as I didn't follow my drawing when looking from the front :woot:. Currently in bits on the bench at work awaiting arrival of some 10mm cable holes. :shh:

    Maybe tonight, fitting and testing. :thumbup:
     
  6. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Fitted, tested and in use. Pictures changed and added. Enjoy. :D
     
  7. spill50

    spill50 Member

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    DIY dual peristaltic dosing pump. More Pics and more.

    Looking good Ian, I'll be doing my own version of this at some point and your post has been very helpful.
     
  8. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    If I was doing it again (when my Juwel Vision 450 arrives, one day.... :lol:) I wouldn't bother with the dual plugs and switches, just wire both pumps to one mains plug and fit whole lot in a smaller plastic case.

    Problem was before I got the pumps and built the system I didn't know how long it would take to prime the pumps and how much liquid would come out of one primed pump whilst waiting for other pump to prime. In the end the amount that would be wasted is quite small, probably wouldn't harm the tank and if worst came to worst I could have just caught the excess ferts in a container anyway.
     
  9. spill50

    spill50 Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Just thinking about it though at least if they are wired independently you can dose micro and macro at different times. Rather than both together. It gives you greater control.
     
  10. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Good point, there is a thread on going at the moment about possible issues of macro reacting with micro and alternate dosing. I think if I ever needed different doses (not sure why I would?) I would just mix up stronger or weaker macro or micro mixes and leave timeclock as is.
     
  11. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Well thinking about it and reading the thread about EI dosing days off http://www.ukaps.org/forum/viewtopic.php?f=11&t=22489&hilit=days off I am now dosing Macro Mon, Wed and Fri and Micro Tues, Thurs and Sat. Set to 1/2 dose for my tank as I am away shortly for 3 weeks so light and CO2 also seriously lowered.

    I also test mixed this morning 40ml of Macro and 40ml of Micro expecting to get instant precipition of iron phosphate, but nothing just looked like wee wee :sick:. No cloudyness at all. Will leave and see what happens. I suspect the acid in my micro is preventing the iron precipitating out.
     
  12. jagz

    jagz Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    hi ian ,

    cracking project and somthing i might consider myself, im very interested in your wirless timer thingy majig, what is it and where did you get it, also can you set it to come on for like 3 mins every 48 hours,

    cheers Ric
     
  13. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Here is the website of the remote control sockets.http://www.homeeasy.eu/

    I got an HE210 remote and 6 switchable sockets HE302 from Ebay for £35.

    You can only set times in 24 hour periods. There are 16 timeslots and you allocate a unit number, start time and end time in each time slot. Its is possible (though not in instructions) to disable a time slot as well, leaving times intact but no switching (might be DEL button whilst setting time). So I am not using my air pump at the moment so I have disabled the time slot.

    I am using the following:

    1. Lights.
    2. CO2.
    3. Wavemaker.
    4. Air pump
    5. Ferts
    6. Water changing pump.

    I have currently got my dual peristaltic pump on 2 B&Q timers set for 7 minutes (10:40pm - 10:47pm), one for micro on Mon, Wed, Fri and Macro on Tues, Thurs and Sat so that I am not dosing macro and micro on same day. Not so sure I need to do this and after holiday might move back to dosing together.

    I have mixed macro and micro in a pot (see my earlier post) and well I didn't get instant precipitation. After 48hours might be slightly cloudy, not sure really.
     
  14. jagz

    jagz Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    thank you for that mate,

    the timer plugs you are using are they the dimmerble type plug timers or are you using just a on/off timer

    Ric
     
  15. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    The non dimmable ones HE302.

    The sockets can respond to more than one remote ID ie unit 1 & unit 2, which confused me at first. I set up my lights on socket 1, worked fine on and off. Then programmed up another socket as socket 2 for CO2 but it also respond to ID 1 as all sockets are supplied ID1. Thus turning my lights on and off also turned the CO2 on an off. :crazy:

    So reset the socket (see instructions) before setting it up the number you require.
     
  16. jagz

    jagz Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    so you can set them up so they dont interfer cant you,

    is there a way of doing it so they can dose every 48 hours so that you could dose the ei method instead of the all in one solution, or do you have to have micro and macro dose at the same time
     
  17. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Actually I am working on my next upgrade to this system, but will have to wait for when I get back from holiday.

    May "invent" and fit an alternate relay circuit, so that via a single mains connection when power is applied it first goes to pump 1. When power is applied next it will go to pump 2. That way a single time clock can control both pumps on alternate days. :D
     
  18. jagz

    jagz Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    i think ill wait for you to do that one and then ill have to copy ya lol , i might make a single one for now for a all in one solution
     
  19. Garuf

    Garuf Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Great little project this! Good work!
     
  20. ian_m

    ian_m Global Moderator Staff Member

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    Re: DIY dual peristaltic dosing pump. More Pics and more.

    Aaaaaaaaaaaaarghh.. Went to bed last night dreaming of relays and peristaltic pumps....supposed to be dreaming of holidays and things like that.

    Had a quick scribble this morning but design needs 2 relays, 1 latching relay and couple of diodes and a 12V power supply (should have bought 12v pumps !!). Suddenly the pump is starting to fail my KISS (keep it simple stupid) principle. Something to think about whilst sunning myself in Florida.
     

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