so im making a drink dispenser and im going to have the Arduino open/close a relay to activate a pump,p for a certain amount of time, I was wondering what the fastest pump would be for my needs, it has to be food safe so it can pump a liquid from one source into a cup for someone to drink, I was looking at peristaltic pumps but they seem to be very slow.
thanks! 
side note: sorry if this isn't the right place to ask I just don't know where I could ask this.
Can you arrange for gravity to help? Then the Arduino just needs some means to stop the flow.
...R
You might take a look at the various ways that the many "bar bot" projects handle this. They now seem to have settled on the use of "bar optics" as the best solution, activated by some form of linear actuator. The bar optic does metering as well as dispensing.
In soda fountains, a bottle of compressed gas provides the force to move the liquid (as well as carbonate it) and so it only needs a valve to control the flow.
Look for a campervan waterpump. Works on 12v.
Bringamosa:
Look for a campervan waterpump. Works on 12v.
If they are like the Jabsco water pump that I have they would not be suitable for food because they would be almost impossible to clean.
...R
The soda dispensers clean themselves by purging water true at the end of the day.
My campervan pump us made for drinking water.
Topic starter said that is to slow....
IcyBlade:
so im making a drink dispenser and im going to have the Arduino open/close a relay to activate a pump,p for a certain amount of time, I was wondering what the fastest pump would be for my needs, it has to be food safe so it can pump a liquid from one source into a cup for someone to drink, I was looking at peristaltic pumps but they seem to be very slow.thanks!
side note: sorry if this isn't the right place to ask I just don't know where I could ask this.
If food safety is a concern, what container holds the source liquid? You really have two options. One is a sealed container with compressed air forcing the liquid out, Or a container that is vented so gravity can force the liquid out. In both cases, some type of replaceable or cleanable valve would control the liquid flowing out of the container.
You will never be able to clean the plastic tubing in a peristaltic pump. You can only sterilize, which may have a bad effect on the tube.
Paul
Bringamosa:
My campervan pump us made for drinking water.
So is my Jabsco pump. But I would not trust it to clean itself of food residue by pumping clean water through it.
...R
I thought it was a drink dispenser not food? TS is looking for something food safe, this is.
At the end of the day remove the pump, pop the cap off and clean/wash the rotor.
If it won't be accessible then it's not a good idea indeed.
Bringamosa:
I thought it was a drink dispenser not food?
I used "food" to mean anything that is not water - sorry for the imprecision.
My pump is a diaphragm pump, not an impeller pump.
...R
Robin2:
Can you arrange for gravity to help? Then the Arduino just needs some means to stop the flow....R
Yes, I can, i was originally going to have the tube go down from a desk to a container like a water jug or pop bottle but now i might but mount a container inside on the top of the drink dispenser could I use some kind of electric valve? (if those exist)
pert:
You might take a look at the various ways that the many "bar bot" projects handle this. They now seem to have settled on the use of "bar optics" as the best solution, activated by some form of linear actuator. The bar optic does metering as well as dispensing.In soda fountains, a bottle of compressed gas provides the force to move the liquid (as well as carbonate it) and so it only needs a valve to control the flow.
I was looking for something that could be turned on and off with a relay so that my RFID reader would read the chip in the bottom of the cup and then dispense the right amount, would there be a way to use this to do that?
Paul_KD7HB:
If food safety is a concern, what container holds the source liquid? You really have two options. One is a sealed container with compressed air forcing the liquid out, Or a container that is vented so gravity can force the liquid out. In both cases, some type of replaceable or cleanable valve would control the liquid flowing out of the container.You will never be able to clean the plastic tubing in a peristaltic pump. You can only sterilize, which may have a bad effect on the tube.
Paul
like I said replying to the first person, I could use gravity to help. what kind of valve could I use that could be activated by a relay?
One possible solution for the "electric valve" is to use a servo to pinch a soft plastic tube.
...R
IcyBlade:
like I said replying to the first person, I could use gravity to help. what kind of valve could I use that could be activated by a relay?
You can use a solenoid valve.
pert:
You can use a solenoid valve.
And here's an example of how to wire one up:
Many drink dispensing machines use compressed air (or CO2) instead of a mechanical pump. Depending on the pressure used and the size of the hoses that can make for quite a good flow (I recall tapping half litres of beer in under 10 seconds, small glasses in 3-4 seconds - yes we always had the pressure a bit high).