Doser with speed controller question

[Seagals]

I am looking to make a doser for cal/alk. Did lots of research and need help deciding on which motor speed controller will work.

This is the doser from amazon:

http://www.amazon.com/gp/product/B00F9MXFFQ/ref=ox_sc_act_title_5?ie=UTF8&psc=1&smid=A1J0AE63I77MT2

I am looking to use it with a 6v or 12v wall wart and here are the speed controllers. The first 2 I like because of separate on off switch.

http://www.amazon.com/gp/product/B00CBBIG34/ref=ox_sc_act_title_3?ie=UTF8&psc=1&smid=A1N6XPDSWPR6EW

http://www.amazon.com/gp/product/B00HTZ5OS2/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A1PPATHVNOJ7UI

http://www.amazon.com/gp/product/B00CW82ZPG/ref=ox_sc_act_title_4?ie=UTF8&psc=1&smid=A1N6XPDSWPR6EW

I like the controllers with the on/off switch but just not sure if the amps are correct. Please help me decide which controller will work best for my situation.

Thank you

 

[FrostyChicken]

Seagals -
Since this is just the head do you know if you can just apply either a controller like you've linked or an appropriate power supply and timer to run these? Usually I see them tied into expensive controller bodies but if you can just wire these up and install them in a job box that would be awesome!

 

[FrostyChicken]

Additionally, the way I understand it 5A (in the case of the first controller) is the maximum amperage it can handle for all loads connected to it. It should be able to handle smaller loads (like an 80mA pump head) just fine. Just at a glance the thing that makes one stick out above the rest is the fact that the Keedox controller is fused. As long as it meets your other requirements that's what I'd go with.

 

[Seagals]

Thanks FrostyChicken. I was originally planning on putting doser on a wall wart and digital timer but the digital timers I have only go to the minute. I was worried about eventually overdosing and thought it would be best to be able to control the motor speed as well.

Do you think I can get a way with the digital timer and not use the controller?

 

[FrostyChicken]

I haven't actually installed one myself yet but I've been doing lots of reading on this site and it seems like people do it both ways. The method I've seen the most often is to let your pump run for a minute and find out exactly how much liquid it pumps in a minute. From that point you set the timer to run the appropriate amount of time to hit the dosage you're looking for (ie a flow rate of 12 mL / min running 3 minutes will get you a total dosage of 36 mL).

That being said a lot of the higher end lab grade pumps I've seen also allow you to control the flow rate. Using adjustable flow rate in conjunction with a timer seems the best route to dial in exactly the dosage you need. Hopefully that helps.

Lastly I'd say you definitely want a timer of some sort since a good majority of these pumps are really designed for continuous operation.

 

[Seagals]

Thanks - I was hoping for one of the other controllers with the on/off switch but I understand the fuse is a good feature.

 

[FrostyChicken]

You could always wire a switch in series with the hot side of power on the board. Basically the same as a light switch in your house does.

 

[EnderG60]

I used those exact heads(but off ebay) for my dosing setup.

They actually flow around 60 ml/min but putting a pot on them for speed control was kinda pointless. It goes from about 60 to 25 ml/min in less then 1/8 turn then just shuts off.

For my lower dosing needs I just got a timer that has a resolution down to 1 sec.