DIY "Drews Doser" Peristaltic Dosing pump

[FiReC]

$4.75 for a set of replacement hoses from APT too, I like that! Might have to try one of these! How do you like it so far killab443? consistent?

[ErikJL]

Has anyone thought about using a large syringe, a low-geared liner actuator, and a pair of check valves? Linear actuator pulls syringe back, pulling in liquid via input valve while output valve stays shut. Linear actuator then reverses, valves are reversed so the liquid goes into the exit valve into the sump.

[BeanAnimal]

Originally Posted by killab443

DIY "Drews Doser" Peristaltic Dosing pump

As many of you know, Bulk reef supply hasn't really been able to keep stock on these excellent pumps. Not only that but at almost 90 a pop they aren't too appealing for everyone's wallets.

Well they certainly are selling a lot at $90 if they can't keep them in stock

[BeanAnimal]

Originally Posted by der_wille_zur_macht

Anyone have info on how these stack up in terms of reliability or sturdiness to conventional peristaltic pumps? i.e. a Masterflex?

Note the same class of pump

The masterflex pumps are built to a much higher tolernace. In many ways they are easier on tubing, but at the same time because the pinching force is higher, they are also harder on tubing. That is you get more precision, but at the cost of tubing life.

[BeanAnimal]

Originally Posted by ErikJL

Has anyone thought about using a large syringe, a low-geared liner actuator, and a pair of check valves? Linear actuator pulls syringe back, pulling in liquid via input valve while output valve stays shut. Linear actuator then reverses, valves are reversed so the liquid goes into the exit valve into the sump.

Yup... a few people have even posted working examples... Others have purchase surplus syringe pumps from eBay. I wne t as far as to design my own pump fixed displacment pump with integrated check balls... will likely never have it built though, as peristaltic pumps are just so easy to deal with.

[killab443]

Originally Posted by FiReC

$4.75 for a set of replacement hoses from APT too, I like that! Might have to try one of these! How do you like it so far killab443? consistent?

Works excellent. Very consistant. I accidently let my alk one on for about 8 hrs last week. I was messing with plugs on my aqua controller and put it in the wrong outlet. Nice cloudy mess I came home to. I lost a hulk monti and dispar antheas .

Originally Posted by ErikJL

Has anyone thought about using a large syringe, a low-geared liner actuator, and a pair of check valves? Linear actuator pulls syringe back, pulling in liquid via input valve while output valve stays shut. Linear actuator then reverses, valves are reversed so the liquid goes into the exit valve into the sump.

IMO thats a Rube Goldberg and chances of something failing in a system like that are high. If it fails often and dosn't dose, it's purpose of convience is no longer there.

ALSO There's actually a video of one of these syringe style dosers on youtube somewhere.

[BeanAnimal]

Originally Posted by killab443

IMO thats a Rube Goldberg and chances of something failing in a system like that are high.

Syringe pumps are used every day in the medical and scientific world. There is nothing Rube Goldberg about it. Reliability is a function of design, a syringe dosing setup can easily be as reliable as a peristaltic setup. Both are postitive displacment pumps that have wear parts and need maintenance.

http://www.syringepump.com/special.htm



http://cgi.ebay.com/LOT-TECAN-CAVRO-...item414cc01560








They come in all shapes, sizes and configurations... both for single stroke infusion and continuous dosing. Some use off the shelf plastic syringes, others use proprietary industrial metal syringes. Nothing Rube about it.

[killab443]

What I thought he was refering to was the DIY syringe pump. Found that video on youtube. http://www.youtube.com/watch?v=TmWOykWHEKA.
IMO I do not think this is reliable. This is exactly what he is considering in a DIY project.

Those medical grade pumps are great your, your right definitly nothing Rube Goldberg about them.

[BeanAnimal]

With a little effort one can construct a reliable syringe doser... However, the peristaltic doser is certainly much easier for the average person to build.

I would certainly hope that the YT video project ended up beign further refined than a block of wood on a 1 RPM motor

I ended up building a Atmega128 based controller for the peristaltic (Masterflex) pumps for dosing and (eventually) automated water changes.

Glad you enjoyed your project

[Hawkdl2]

2 Master Flex pumps and a few solenoids automating Kalk, ATO, and water exchanges. I'm using an Apex controller. An additional small peristaltic pump drains away OSW from the sump at the DT during exchanges.

We use piston pumps and syringe dosers in my lab for various specific applications (like filing vials with experimental biologics for clinical trials) where very accurate small volumes are required, but I don't see them being appropriate for most reef applications. We use peristaltic pumps for every application that I would consider similar to those we see in reefing.

[BeanAnimal]

I would imagine a better use for the sryinge dosers would be for zeovit or similar systems were multiple products are used in small amounts on a regular basis.

My design for a positive displacment piston pump was for doing continuous water changes. I did not want to have to worry about keeping two peristaltic pumps sequenced with regard to flow and/or worry about tubing failure. In the end I have no desire to have the parts built and don't have the tooling to do it myself.

[Hawkdl2]

To avoid sequencing the pumps, I perform small volume a sequential addition/subtraction of about a gallon or so at a time - as frequently as I desire. Float switches, with emergency back up switches keep the pumped volumes correct and over ~6 months now, my tank's SG has remained perfectly stable. It works well and easy to set up. Tubing failures can occur, but are rare with Pharmed tubing and Masterflex pumps if replaced regularly. Recognizing "anything" can happen, I also have time limits on the two pump functions. Worse thing that can happen is a gallon of water hits my garage floor before the system shuts off the pump.

[ErikJL]

You guys are correct, but here's one that more accurately shows what I had in mind:

http://www.youtube.com/watch?v=8uIymKcx-qg&NR=1

Will it be less robust? Probably, just as any DIY project is likely to be less robust than a manufactured item. But if you like to tinker, as I do, these things are just cool.

[CorkPullerPHL]

What model's of Masterflex are suitable to reefing? A quick search yielded a ridiculous number of results.

[FiReC]

ordered my parts for the drews doser from apt today, can't wait!

I don't know if anybody noticed, but you can get it fully enclosed with a power cord for 97+shipping from apt as well in case you didn't want to enclose it yourself.

[BeanAnimal]

Originally Posted by CorkPullerPHL

What model's of Masterflex are suitable to reefing? A quick search yielded a ridiculous number of results.

Just about any of them

[Hawkdl2]

I prefer models with adjustable speed.

As and FYI, I bought the two I'm currently using on ebay for about $50 and $70. They don't come up all the time, but if you keep an eye out for them you can get one pretty cheap.

[golfish]

We cleaned out the storage room last week. I know we had three of these at one time but I only could find one in the trash bin. These things are beast, I bet it tops out at 10 pounds.

[FiReC]

Thanks for the info, here is my build

The Parts


Removing the pump head


Testing the fit - that radio shack box listed by the OP is a perfect fit. Note those little clips on the sides of the pump, I believe you can easily swap motors available from apt .. which means if instead of dosing I want to do top off with a higher flow rate, no problem! The little ac motors are cheaper than a whole unit. If it ever burns out for whatever reason, swapping in a new one should be easy.


This is the mounting plate the peri pump comes with. I clamped it to the front panel and used it as a template to drill all the holes with a 5/64 bit initially to go through the mounting plate hole, than I used a 9/64 from the front to make it big enough for the screw to fit through.


Ok this I thought was pretty cool, the holes on the mounting plate are tapped m3x.5 which happens to be the size of those little computer case screws I have laying around everywhere from building computers. Its the one with the tighter thread in my hand.. the ones used to secure a cdrom to a mounting rails, or motherboard to case. NOT the screws used to secure pci cards to the case which is the thicker thread screw in my hand. You need 2 of the tighter thread screws per pump.


Motors mounted to the plate


Wire it up


Before putting the heads back on

[FiReC]

Putting the heads back on , there are really only a couple parts




Note the little holes near the base of the clear plastic housing on the project box face plate, there are knobs on the base of the clear housing that sink into the holes and make the housing completely flush against the face plate. Thankfully there are holes in the mounting plate for all this stuff, just punch a 5/64 bit thru like I said before.


rock on

[sjm817]

Nice info. I have a set of Drews and saw the APT lablel. I went to the sight to check it out, but already had them at that point. FYI, here is another source for the "Drews" APT pumps:
http://www.tbaquatics.com/shop/smart...doser-390.html

[killab443]

Nice! Glad you used the info. What size pumps did you go with?

[cediss]

Me too. Thanks that is. Got my pump from APT Monday, net to put it in a project box, but it's working so far!


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[FiReC]

Originally Posted by killab443

Nice! Glad you used the info. What size pumps did you go with?

same size you did 8 RPM, 3 MM id for 1.5 mL/min

[cediss]

Same pump here!


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