Cake pan + skateboard wheel + bike brakes = homemade peristaltic pump??

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TheFlyingBeer

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In my efforts to build an electric HERMS system I decided to attempt to build my own pumps :drunk:. I was really intrigued by peristaltic pumps due to their ability to work in reverse, self prime, meter (dose), and ease of cleaning/sanitizing. I didn't want to post anything on my pump design until I had a successful trial run of the first build... that time has come so here goes:



The base design is a 360° eccentric peristaltic that uses a single roller to move the fluid in either direction by squeezing a silicone tube.

The major components of the pump head are:
1. 9" round spring-form cake pan
2. Long-board skateboard wheel and bearings
3. 160mm mountain bike brake discs
3. Bolts, nuts, and washers from McMaster

I built the design in 3D first to provide an initial validation that this thing might stand some sort of chance of actually working.



The skateboard wheel is mounted to a hub created by bolting together a couple of standard mountain bike brake discs.



The wheel rotates and squeezes the tubing causing the fluid to be pumped. The distances of the wheel from the outer wall can be changed due to the slots cut in the brake discs.



The back is ready to have a motor (going down the path of a large computer controlled stepper) mounted to it.



Should end up looking something like this with additional mounting hardware:



Ran the pump tonight using my cordless drill as a temporary motor and it worked really well. Moved roughly half a standard ale pale worth of water to a second pale in around a minute, and then transferred it all back to the original. My system design calls for two of these pumps so once I hash out all the small details I will build a second one.
 
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TheFlyingBeer

TheFlyingBeer

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Why not add 2 more wheels?
Each wheel occludes the tube, providing slightly less pumping capacity and, more importantly, creates additional friction wear on the tubing. With the 360° eccentric design only one roller is needed to maintain suction.
At some point once I finish getting an actual motor connected to this I want to test the longevity of the tubing so I can make plans to replace it on a regular schedule rather than have a failure in the middle of a brew.
 

runningweird

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I love it!

to build one of these pumps what kind of cost are you looking at?

found this video, idea seems similar:
 
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jsguitar

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That's really cool! I would've never thought of doing something like this. I'd love to see a video of yours in action when you're completely satisfied with it.
 
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TheFlyingBeer

TheFlyingBeer

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Sourced nearly everything from McMaster or eBay. The pan itself was from Sears, figured I would mess something up during the build so I went with a local source on that.

Here is the current BOM:

The stepper motors and controllers should end up costing about $150 for each pump so these two won't be all that cheap. It should be possible to hook the pump head up to a much cheaper AC or DC motor but I really want the control provided by a large stepper.
 

wyoder

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Lookin great TFB. Nice use of parts!

Are you planning to use your uController from your HERMS build to provide motor control? Hoping to build you're own bridge?
 

ChuckO

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Great design! I like the creative use of existing parts in place of custom machining everything.

I can picture two of these on a common shaft used for sparging, one from the HLT to the mash tun and another from the mash tun to the boil kettle. That would keep the wort level constant over the mash.

Have you tried to hold a constant motor speed and use a valve to throttle the input to the pump? I think that this would be useful in a manual setup where computer control wasn't practical.

Rigidity might be improved if you used another spring form pan bottom on the other end of the circular form.
 
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Why a stepper motor? The pump requires continuous motion, not the ability to move in exact increments. A gearmotor and variable power supply would do what you need. They are usually available at surplus stores.
 
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TheFlyingBeer

TheFlyingBeer

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Great design! I like the creative use of existing parts in place of custom machining everything.
Thanks. The bike brakes were a big turning point in the design, until I discovered they fit just right I was looking at different ways of building the hub. This pump has less than 10 minutes of use on it so who knows how well it will hold up but it is very solid right now. As far as adding another pan bottom, it is sturdy enough so far... I guess time will tell. I have seen videos of using valves to control the flow but I currently don't plan to test that out. I plan to build a second pump eventually for sparging once this pump has been proven out.


What kind of rpms would be good for this?
Made a simple calculator in Excel to determine the RPMs needed to move specific volumes. Based on the pan side and the tubing ID the pump should move roughly 0.023gal/rev (~2.9 fluid oz). So to move 1gpm I would need 44rpm. A RPM range of 0-300 (0-7gpm) would be ideal but lower would still probably work.

Why a stepper motor? The pump requires continuous motion, not the ability to move in exact increments. A gearmotor and variable power supply would do what you need. They are usually available at surplus stores.
I like the ability to precisely control RPMs without any additional closed loop feedback. The motor/drive is the last part of the design that remains up in the air. The hardest part for me is to determine how to size the motor. I found a datasheet on a similar Masterflex pump that was the same head size and accepted 1in tubing. The motor for that pump was rated at roughly 1200oz-in and could move at higher rates than I expected I would need. I was shooting for a stepper around 600oz-in but I might consider a cheaper variable speed DC gearmotor design with some sort of feedback. Any suggestions would be appreciated. Current plan was to control the stepper using the parrallel port and some code in Labview (what my brewery currently runs on). It should be easy enough to program acceleration, RPMs and deceleration.
 

MonkeyWrench

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Awesome design! Best one yet.

+1 for DC motor. Maybe even a 555 PWM unit and SSR for the control.

I might seriously think about making one of these. I want a DC March pump, but they are $222 compared to their 110v counterpart at $145.
 

thantos

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I was shooting for a stepper around 600oz-in but I might consider a cheaper variable speed DC gearmotor design with some sort of feedback. Any suggestions would be appreciated. Current plan was to control the stepper using the parrallel port and some code in Labview (what my brewery currently runs on). It should be easy enough to program acceleration, RPMs and deceleration.
How about using a 12 or 24vDC motor, and a on/off Rheostat/Potentiometer, like a dimmer switch to control the rpm? Plenty of old car starters, window and windshield motors out there to be used!
 

stamandster

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That's very nice. I would think you'd need at least two wheels to maintain constant suction. Definitely going to do this instead of a normal pump because of all the plus's. A watcher thread for sure!
 

Lucky_Chicken

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SWEET!!! yet again HBTers have caused me to want to build something else, and this could get me in the pumping buisness (allow me to recircuilate mash) with some old motors I have sitting around for pretty cheap!

thanks for the great build pictures!
 

OneHoppyGuy

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Ran the pump tonight using my cordless drill as a temporary motor and it worked really well. Moved roughly half a standard ale pale worth of water to a second pale in around a minute, and then transferred it all back to the original. My system design calls for two of these pumps so once I hash out all the small details I will build a second one.
Not quite sure I understand the quantity you moved during the minute interval. Do you mean 1/2 of a pail? Approximately how many quarts? :confused:
 
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TheFlyingBeer

TheFlyingBeer

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Not quite sure I understand the quantity you moved during the minute interval. Do you mean 1/2 of a pail? Approximately how many quarts? :confused:
Without measuring it was around 2-3 gallons so a bit less than half of the bucket.

Getting the tubing length in the pump just right is kind of a pain in the ass, too short or too long and it tends to spiral it out the front over time as it runs. Might be an issue with the 360 spiral design in general... needs more testing.
 

thantos

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Without measuring it was around 2-3 gallons so a bit less than half of the bucket.

Getting the tubing length in the pump just right is kind of a pain in the ass, too short or too long and it tends to spiral it out the front over time as it runs. Might be an issue with the 360 spiral design in general... needs more testing.
Was the liquid you tested with hot or cold? I am wondering about thermal expansion of the tubing making it grow even more?
 
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TheFlyingBeer

TheFlyingBeer

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Was the liquid you tested with hot or cold? I am wondering about thermal expansion of the tubing making it grow even more?
So far I have just been testing with cold tap water in the mid 60's. I think (nothing to back this up) that the expansion of the tubing will be negligible.


I hate to say it so soon into the build but I think it might be time for rev B:



The issue I am having with the 360° design is the spiral in the tubing causes it to slowly creep up the wall of the pump head and eventually it moves clear of the roller causing the pumping to fail. In this design I added a second wheel (still have 2 to spare) and the tubing now sits on a flat plane rather than a spiral. The second wheel was needed to maintain occlusion since the tubing only covers 250° of the circumference now. The pumping capacity per revolution is now less by ~30% but the tube should remain centered. Might try to swing by Sears tomorrow evening and buy cake pan #2 then the brake disks need a little modding...
 

Bumbler

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So far I have just been testing with cold tap water in the mid 60's. I think (nothing to back this up) that the expansion of the tubing will be negligible.


I hate to say it so soon into the build but I think it might be time for rev B:


The issue I am having with the 360° design is the spiral in the tubing causes it to slowly creep up the wall of the pump head and eventually it moves clear of the roller causing the pumping to fail. In this design I added a second wheel (still have 2 to spare) and the tubing now sits on a flat plane rather than a spiral. The second wheel was needed to maintain occlusion since the tubing only covers 250° of the circumference now. The pumping capacity per revolution is now less by ~30% but the tube should remain centered. Might try to swing by Sears tomorrow evening and buy cake pan #2 then the brake disks need a little modding...
Newly subscribed.

Nice build - neat, clean and off the shelf parts.

2 cents - silicone tubing does not expand when heated. It's on on the internet - it must be true.;)
 

Tat2nBrew

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So far I have just been testing with cold tap water in the mid 60's. I think (nothing to back this up) that the expansion of the tubing will be negligible.


I hate to say it so soon into the build but I think it might be time for rev B:



The issue I am having with the 360° design is the spiral in the tubing causes it to slowly creep up the wall of the pump head and eventually it moves clear of the roller causing the pumping to fail. In this design I added a second wheel (still have 2 to spare) and the tubing now sits on a flat plane rather than a spiral. The second wheel was needed to maintain occlusion since the tubing only covers 250° of the circumference now. The pumping capacity per revolution is now less by ~30% but the tube should remain centered. Might try to swing by Sears tomorrow evening and buy cake pan #2 then the brake disks need a little modding...
This is a much more stable design in my opinion because the axial load on the drive shaft is basically equalized. I use a modified smaller medical peristaltic pump to fill bottles in my warehouse and have even considered making a few of my own from scratch as production demands rise. The ones I have now are about 180° and I am getting a slight pulse in the flow so I might have to steal some of your idea and increase it to 250°-270° range. Nice project by the way!
 

tdogg

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this is awesome! im a big fan of DIY but i would have never thought of building a pump head. subscribed.
 

MonkeyWrench

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Maybe line the cake pan sides with some of that no slip drawer liner? Maybe the pressure from the wheel and grip between the silicone hose and non slip material would help keep the hose in place?
 
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TheFlyingBeer

TheFlyingBeer

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Thanks everyone for the kind words.

Rev B is alive!






Picked up a second cake pan tonight and went to work. Had to modify the disk brakes for a 4-bolt, 2-wheel configuration versus the previous 3-bolt, single wheel. Cheap drill press and a nice step bit made easy work of it. I changed the method in which the tubing is secured to the entrance and exit with very positive results. Four holes were drilled in each "flap" and a couple zip-ties are used on each end, the tubing is going no where.



Had a chance to run it for a short while tonight and I was much happier with its performance and the stability of the tubing inside the pan. I actually measured the water this time. Hooked up to my Ryobi 18V cordless drill it moved 3 gallons in 34 seconds with the drill running at about 80% of its max power (no idea the RPM). The pump is understandably more balanced than the first attempt which is also a positive.
 

Flomaster

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**** yeah.

-=Jason=-
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Medevac_Chief

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WOW! This is an awesome build!! Going to look up parts now! Where did you find the 2 piece metal hose clamps?
 

sanch

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Sweet build man !!!
I was just thinking. If a kernel of grain or a hop particle got caught under the wheel it might get smashed in to the tubing causing some sanitation issues or premature wear on the tubing.
 

sanch

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maybe that's why the dude in the youtube video had them spring loaded?
 

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