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Looking for a pump — Parallax Forums

Looking for a pump

CircuitsoftCircuitsoft Posts: 1,166
edited 2013-12-21 06:31 in General Discussion
I want to build a teapot with settable temperature and brew time. My idea is to have a tea-strainer above the pot, and a pump to pump water/infusion (40-80GpH) from the heated pot on the bottom into the tea strainer, but only for the duration specified in the brewing recipe.

The challenge is finding a pump that can tolerate water up to boiling temperature. Does anyone know where I could find such a thing?

Thanks,
- Alex

Comments

  • xanaduxanadu Posts: 3,347
    edited 2013-12-17 12:33
    Look at home brewing pumps for beer. I definitely do not do that in my garage but I'm guessing that they're designed to withstand very high temps.
  • Dirty HowiDirty Howi Posts: 20
    edited 2013-12-17 12:50
    looky here

    its only 15gph but runs on 6v :) good to 212f
  • bomberbomber Posts: 297
    edited 2013-12-17 12:50
    Probably not the most reliable in terms of getting an accurate flow rate, but a peristaltic pump with tubing rated for high temperatures may work.
  • kwinnkwinn Posts: 8,697
    edited 2013-12-17 19:49
    bomber wrote: »
    Probably not the most reliable in terms of getting an accurate flow rate, but a peristaltic pump with tubing rated for high temperatures may work.

    I beg to differ on the accuracy of the flow rate. Peristaltic pumps are used in hospitals because they have precise flow rates.
  • kwinnkwinn Posts: 8,697
    edited 2013-12-17 19:57
    @Circuitsoft

    You can probably convert an inexpensive coffee maker hot plate to do that. The tube under the hot plate has a fixed volume, and each time the water gets hot enough to vaporize it forces that volume up into the filter basket. Count the number of times that happens to get the volume you want.
  • ErlendErlend Posts: 612
    edited 2013-12-18 03:33
    I love this idea. Instead of pumping the hot water - which ideally should be as close to boiling as possible, for best results - why don't you pump cold water through a heater? With a suitable heater (e.g. 'thermoblock' found in an espressomachine) and a temperature sensor on the outlet you should be able to get very accurate control. From my understanding of tea-brewing, you should control flow rate rather than temperature - which must be ~boiling - in order to control brewing time.
    3674_qmtb.jpg


    Erlend
    3674_qmtb.jpg
    255 x 224 - 18K
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-12-18 05:05
    If you try the suggestion above and pump cold water, Harbor Freight has cheap fountain pumps. I think I got mine for $8 and ran it for a year. It still works, I had to use the rig for another project.
  • Tim-MTim-M Posts: 522
    edited 2013-12-18 07:30
    Also for cold water, SparkFun has these pumps and valves to offer:

    https://www.sparkfun.com/search/products?term=pump

    Tim
  • kwinnkwinn Posts: 8,697
    edited 2013-12-18 09:46
    The thermoblock approach could also eliminate the need for a pump if you hook it up to the cold water supply.
  • jdoleckijdolecki Posts: 726
    edited 2013-12-18 10:30
    American Science and surplus

    http://www.sciplus.com/
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2013-12-20 16:50
    kwinn wrote: »
    @Circuitsoft

    You can probably convert an inexpensive coffee maker hot plate to do that. The tube under the hot plate has a fixed volume, and each time the water gets hot enough to vaporize it forces that volume up into the filter basket. Count the number of times that happens to get the volume you want.
    Boiling water will actually burn a lot of loose-leaf teas, so sub-boiling water is necessary, though I would like to support boiling water when necessary.
    Dirty Howi wrote: »
    looky here

    its only 15gph but runs on 6v :) good to 212f
    That looks about perfect. Thanks!
    Erlend wrote: »
    I love this idea. Instead of pumping the hot water - which ideally should be as close to boiling as possible, for best results - why don't you pump cold water through a heater? With a suitable heater (e.g. 'thermoblock' found in an espressomachine) and a temperature sensor on the outlet you should be able to get very accurate control. From my understanding of tea-brewing, you should control flow rate rather than temperature - which must be ~boiling - in order to control brewing time.
    3674_qmtb.jpg


    Erlend
    That's another fantastic idea. As mentioned above, though, I do want sub-boiling water, but your suggestion does allow for that. For flow rate, I just want to make sure I don't overflow the container I hold the tea leaves in. The challenge will be to find the thermoblock.
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-12-20 17:07
    Circuitsoft wrote: »
    The challenge will be to find the thermoblock.

    Maybe a hot glue gun from the dollar store? Take the heater out and wrap it around a small copper tube?
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2013-12-20 17:10
    prof_braino wrote: »
    Maybe a hot glue gun from the dollar store? Take the heater out and wrap it around a small copper tube?
    Probably need a lot more heat than that. All the hot-glue guns I've seen are 10-40 watts (my parents have an old 70-watt gun), and I expect to require several hundred watts to heat any appreciable amount of water.
  • ErlendErlend Posts: 612
    edited 2013-12-21 01:12
    You will need at least 1000W for sure. Google returned this one, for instance.
    Erlend
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-12-21 06:31
    How about salvaging the heater unit out of a dead coffee pot? I have a couple Mr Coffee looking things, and they have two thermal fuses. I guess there are two for safety. Anyway remove the dead one, and then control the temp by controling the flow rate? control a valve on the water supply, and save on the cost of a pump as as suggested
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