DIY "Drews Doser" Peristaltic Dosing pump
- Thread starter killab443
- Start date
Found this to be a very informative thread and I was about try and build my own 2 part dosing solution. Had a couple of questions before I bought parts.
Has anyone tried .8 mm tubing with the pumps ( 8 rpm, 115V). With a slower flow rate would it not be a better option for a more gradual addition of the two part. Thanks
Has anyone tried .8 mm tubing with the pumps ( 8 rpm, 115V). With a slower flow rate would it not be a better option for a more gradual addition of the two part. Thanks
Gorgok
New member
Assuming its a DC pump, you can change the drive voltage to something lower to slow it down. Going higher than rated will speed it up too, but at the cost of motor life...
You can probably also change the tube size, assuming yo can get a different ID without changing the OD too much.
You can probably also change the tube size, assuming yo can get a different ID without changing the OD too much.
I know this thread is old, but this seems like the DIY i'll be doing next.
Any feedback from users that have gone this route?
It's been between 3 to 7 years for some so there should be a lot of long term reliability feedback.
Please post. You'd be helping a lot of people who would really appreciate it.
Any feedback from users that have gone this route?
It's been between 3 to 7 years for some so there should be a lot of long term reliability feedback.
Please post. You'd be helping a lot of people who would really appreciate it.
five.five-six
Well-known member
There’s about a gazillion 12V DC perastolic pumps on eBay now ranging from $10-30, I’m wondering if any of them are reliable enough to use as afeed pump for my calcium reactor.
der_wille_zur_macht
Team RC
I used some cheap ones as a stopgap until I saw a good deal on a "real" peristaltic pump with the right specs. Brand name industrial pumps are incredibly reliable, rebuildabe, etc etc. and they come up used once in a while at great prices.
The ones I tried were roughly $10 I think, the same old 12v dc pumps you see everywhere. They lasted maybe 3 or 4 months. Since I went in to it expecting poor results it wasn't a big deal, but I woudn't want to rely on them longterm.
The ones I tried were roughly $10 I think, the same old 12v dc pumps you see everywhere. They lasted maybe 3 or 4 months. Since I went in to it expecting poor results it wasn't a big deal, but I woudn't want to rely on them longterm.
five.five-six
Well-known member
Right, 3-4 months is all I’d Expect from a $10 pump, I’m just wondering if for $30-50 I might find one that would last for years.
der_wille_zur_macht
Team RC
I didn't see much difference except for price between the $10 pumps and the $30 ones.
I actually bought more of these than I needed and ran them essentially as closed loops until they failed because I was curious about the reliability and modes of failure. The tubing was a weak spot, which you could replace, and is a weak spot in any peristaltic pump, by design. But eventually, these cheap pumps started slipping, the roller cage is just a friction fit on the shaft and after a while the thing would get so worn out that the shaft would just spin in the cage. I haven't done similar experiments on $30-50 pumps, but in looking at them, they all also have pretty much the same roller cages in friction fit designs as the cheaper pumps.
Around the time the "Drews doser" style of pumps started getting a bad rap a few years ago, I went to a more robust, but still hobby-grade pump that was available new at the time for maybe $70 - 80. It had a gearbox, which ended up being the weak link. The gears would get worn and start to bind after maybe a year. You'd know when it started happening because the pump would make a terrible high pitched grinding squeal every time it ran, then eventually it would just lock up. I could take the gearbox apart and lubricate it, but once it reached that point it would fail again after maybe 2 or 3 months.
The "real" pump I bought for my current tank was probably $300 or $400 new, I paid $75 for it on eBay. It looks brand new. If you search carefully and are patient, there are good enough deals on higher end pumps that I wouldn't bother with the cheap ones.
I actually bought more of these than I needed and ran them essentially as closed loops until they failed because I was curious about the reliability and modes of failure. The tubing was a weak spot, which you could replace, and is a weak spot in any peristaltic pump, by design. But eventually, these cheap pumps started slipping, the roller cage is just a friction fit on the shaft and after a while the thing would get so worn out that the shaft would just spin in the cage. I haven't done similar experiments on $30-50 pumps, but in looking at them, they all also have pretty much the same roller cages in friction fit designs as the cheaper pumps.
Around the time the "Drews doser" style of pumps started getting a bad rap a few years ago, I went to a more robust, but still hobby-grade pump that was available new at the time for maybe $70 - 80. It had a gearbox, which ended up being the weak link. The gears would get worn and start to bind after maybe a year. You'd know when it started happening because the pump would make a terrible high pitched grinding squeal every time it ran, then eventually it would just lock up. I could take the gearbox apart and lubricate it, but once it reached that point it would fail again after maybe 2 or 3 months.
The "real" pump I bought for my current tank was probably $300 or $400 new, I paid $75 for it on eBay. It looks brand new. If you search carefully and are patient, there are good enough deals on higher end pumps that I wouldn't bother with the cheap ones.
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