Components for small peristaltic pump

[John Rock]

Hi!

I know almost nothing of electronics (never had a need yet) and would like to build a liquid chlorine dispenser for my pool. For the pump that will bring chlorine from the reservoir to the pool line, I identified 4 components I think I need: peristaltic pump, controller, ac-dc converter and a timer that I'll buy locally.

I found a cheap 12v pump and PWM controller on eBay (10$ for both), but for the transformer, most add "LED" in the description.

Other than having 110ac to 12dc in the transformer specs, do I need to consider anything else?

Here are the links to my pump and controller if usefull:
http://m.ebay.com/itm/172142328082

http://m.ebay.com/itm/191523216758

Thanks!

 

[Gryd3]

Hi!

I know almost nothing of electronics (never had a need yet) and would like to build a liquid chlorine dispenser for my pool. For the pump that will bring chlorine from the reservoir to the pool line, I identified 4 components I think I need: peristaltic pump, controller, ac-dc converter and a timer that I'll buy locally.

I found a cheap 12v pump and PWM controller on eBay (10$ for both), but for the transformer, most add "LED" in the description.

Other than having 110ac to 12dc in the transformer specs, do I need to consider anything else?

Here are the links to my pump and controller if usefull:
http://m.ebay.com/itm/172142328082

http://m.ebay.com/itm/191523216758

Thanks!

How accurate do you need to be?
A simple DC motor/Timer will not give you very consistent performance, but it 'can' provide you with a decent ball-park figure.
As far as the considerations you requested for the PSU... you also need to satisfy the mA rating.
The motor you have, as well as the controller will draw current. You must be able to supply this current or the motor will run slower and may damage the transformer.
Simply find the current draw of the motor, or share the model number with us and we can see if we can find it.
You can also search for 'AC-DC converter' instead of transformer. That might give you more results.

 

[John Rock]

Thanks for replying Gryd3!

From the specs I read for the pump, the flow rate is 20-60ml per minute. This is more than enough since I don't think I'll need more than perhaps 250 ml per day. So my plan is to use the PWM to slow down the pump at a minimum and see what the actual output is per hour. Then, with the timer, I'll set the pump to run the amount of time required per day, when the pool pump is working of course. The chlorine pump could vary by 50% and it wouldn't matter to much, as long as it's fairly consistent on a weekly basis and averages out.

The mA rating for the pump is 80mA. For the controller, it says "maximum continuous output current 8A", overload is 10A. And it's ajustable from 10% to 100%. Does that mean that the minimum current is 0,8A or 80mA?

My thinking was that 80mA "sounded" very little, so any 12v transformer/converter would work. Then the "LED" stuff made me wonder is there are many kind of transformer/converters...

Is this the missing info you needed?

 

[73's de Edd]

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Sir John Rock. . . . . . .

I can see your power supply as being fully adequate.
Now I'm just fully trying to digest the max 5000 rpm spec on the universal motor.
And I don't quite think that I see a gear case spaced in there between the motor shaft and drive roller.
I'm used to seeing medical applications at a creep speed and with 100 rpm being FAST and
considering an attained 500 RPM as being WARP speed.
With the friction encountered in the pressure roller(s) on the silicone tubing I would expect somewhat of a current drain and adjunct pulling down of the the speed.

Have you found any motor current consumed specs using constant 12VDC , with no liquid drive, just spinning the roller(s) ?


ASIDE THOUGHT:
I wonder how this would work when connected to a paint spray gun, especially when revving up to its very highest motor speeds.


73's de Edd


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[John Rock]

Hello 73's de Edd!

5000 RPM does sound awful fast. Perhaps it's the max speed of the motor spindle, without the other pump parts. I found this in the specs : Rotate speed: 0.1-100 rpm. This aligns with your observations.

Does you power supply comment infers that any will do? This may sound dumb, but are all my old power supplies AC/DC converters, like for a small hub or router? If so, could I just use that?

Not sure I understand the thought around spray guns; can you elaborate?

Thanks!

 

[73's de Edd]

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Sir John Rock . . . . . . .

Good to confirm that units much more realistic high end operating speed . . . . . . . . which you found in the specs.
Of course if you have unit in hand and expose the silicone tubing and pull it out such that the roller can be free and spun by hand.
You would know in a hurry if there is any intermediate gearing involved by the involved retraint in rotating it.


On the power supply . . . . I just knew that the one that you specified should be greater than is required.
The REAL evaluation would be to have pump in hand and then power it up with that specified power supply and get it running continually to find its current drain and voltage required to accomplish your uppermost flow needs.
Then you could digress backwards on the minor power supply that you might want to use, by using a lesser one that could also fulfill those power level needs.
It would be a piece of cake onward from that situation, with it only getting timed partial / intermittent operation.

I was just thinking of fast microbursts of PROPERLY thinned paint fed to a sprayhead. Then the thing of beauty would be the cleanup, where you just reran solvent /cleaner thru the tubing until cleansed.
Then you just save that slightly tainted solvent to use for your next need in the thinning of the mix of the same color.
Of course . . . .this just might be the concept behind one type of "airless" spray guns..


73's de Edd


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[Alec_t]

My thinking was that 80mA "sounded" very little

That is the rated current when the motor is operating at full speed. At lower speeds the current will be more (it is at maximum when the motor is stalled or just starting up) because the back-emf generated by the motor is less. If you use PWM control, the motor will be drawing short bursts of relatively high current (albeit the average current would be low), so when choosing a power supply I'd be looking for one with a 12V 1Amp rating to ensure it can provide those bursts.