Accurately dispense liquid volumes

  1. I am considering the economic viability of a project that must accurately (within a tolerance of, say, 0.5ml) dispense volumes of water from a tank at a constant volumetric flow rate of around 50ml/s.

    Within the tank, the water may be held at pressures between 1 and 6bar; and at temperatures between 4 and 18°C. The temperature should not be changed by more than 0.5°C during the dispensing.

    The volume to be dispensed will be controlled electronically (between 10 and 250ml).

    It is not clear to me what would be the simplest approach, from a pressure regulator in series with a timed valve (which I doubt could achieve the desired accuracy) to some advanced pumping arrangement controlled by electronic flow measurement devices. I imagine it could also be possible to determine the volume of water dispensed via changes in volume remaining in the tank; e.g. the tank could be weighed or include a floating ball measure.

    Aside from the criteria detailed above, other considerations include: minimising cost (obviously); ease of regular cleaning (the water is for human consumption); and minimising the physical size of the device.

    I would be extremely grateful for your suggestions.
  2. jcsd
  3. I dont understand? If you wish to measure your water that accurate then could you not just use a graduated cylinder with a level sensor on the side?

    This idea seems very odd to me, please explain as I must be missing something?
  4. Bobbywhy

    Bobbywhy 1,864
    Gold Member

    Anestheistiologists use automated fluid (anesthesia) dispensers to control the infusion of volumes of the drugs into patients.
Know someone interested in this topic? Share this thead via email, Google+, Twitter, or Facebook

Have something to add?