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counting bottles

Discussion in 'Electronic Basics' started by david b, May 20, 2006.

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  1. david b

    david b Guest

    In our milk bottling plant we would like to have a means of counting
    bottles as they leave the filling machine on a conveyor.
    We don`t need to store the numbers, just an easy to read display that
    can be reset to zero every time we change bottle size.
    Any thoughts on how to acheive this ?
    David B
  2. JeffM

    JeffM Guest

  3. Jasen Betts

    Jasen Betts Guest

    see the engineer who maintains the conveyor (and other plant), there's all
    sorts of different resetable counting mechanisms available, he may even
    have a used one you can have cheap.

    If you want to do it yourself consider attaching an light-beam sensor to an
    electronic counter. (maybe a cheap pedometer could be modiified?)
  4. Chris

    Chris Guest

    Hi, David. Even if you're paying yourself less than minimum wage and
    parts were free, you couldn't make a counter for less than you can buy
    one. And almost all of them have a reset feature either built into the
    front of the display, or have provision to attach an external switch
    for reset.

    The sensing part is a little more difficult. If your milk bottles are
    full, it should be fairly easy to insert one of those microswitches
    with lever activators in line, and then use the contact closure to
    increment the counter. If that's not practical, there are many
    photoelectric switches that can sense whan the beam is broken and give
    an electrical output. The downside to that is that you'll need a
    separate power supply for the sensor. But many counters have built-in
    power supplies for external sensors, too.

    Now, if the bottles are not filled, and are transparent, and you can't
    use a microswitch, you might have more problems. The photoelectric eye
    sometimes is not reliably switched by clear glass or clear plastic.

    Your question is so general, it's kind of difficult to give a good
    answer without writing a book. Why don't you take the time to describe
    your problem a little better, and possibly someone can then give you a
    more specific answer. Please include:

    * Number of counts per second, including how long the microswitch
    would be closed or the eye would be triggered.

    * Possible to use a microswitch?

    * Milk bottles full?

    * If milk bottles empty, then glass or plastic? Glass/plastic
    transparent, translucent, opaque? If transparent, opaque to infrared?

    * Is this just a school class question? You'll get a lot more useful
    of an answer if you just 'fess up. Nearly all dairies are fiercely
    automated, and this actually sounds more like a ringer question.

    Good luck
  5. david b

    david b Guest

    Thanks for the reply
    Genuine question this.
    We have a small on farm dairy we set up last year.
    Just seeking guidance on whether something is available off the self or
    we need to aquire components.
    We have full poly bottles
    1 every 2 seconds
    should be possible to fix a microswitch to the conveyor guide rails
  6. R.Wieser

    R.Wieser Guest

    david b <> schreef in berichtnieuws

    Hello David,
    A simple light-beam door-opener sensor you can buy everywhere connected to a
    as simple mechanical push-to-reset pulse-counter perhaps ?

    Rudy Wieser
  7. Chris

    Chris Guest

    Hi, David. Just asking to get an idea of what you needed.

    If you can work out a mechanical setup to sense the bottles, your job
    has become much easier and less expensive. Some microswitches
    (trademarked name, they're made by many suppliers) have rather long
    vane actuators at their ends which can be depressed by the bottles
    going by. This has the real advantage of greatest simplicity, but you
    have to make sure product goes only one way on the conveyor. On some
    of the long vane actuators, you can bend the end back to give it a
    roller effect. But be sure to get one that's rated for dry contact
    switching. You're going to be switching a low voltage at a low
    current. If you use a standard microswitch, the contacts will oxidize
    over time and become unreliable long before end of life.

    As I mentioned before, it's far easier and more efficient just to
    purchase a counter module than to make one. There are many of these
    available which will work for you.

    Unless you want a big display, you can go with one that's self-powered
    (e.g. a 3V replaceable lithium battery that should last for years).
    You need to specify one that has contact actuation (for your
    microswitch normally open contacts), and that has either provision for
    an external reset button or one built-in on the front display of the
    counter, or both. The contact activation part is critical -- if you
    get one that's voltage-actuated, the contact bounce of the microswitch
    will lead to multiple counts per bottle, especially as the microswitch
    contacts get old.

    One provision I hadn't taken into consideration is that your
    electronics may need to be rated for washdown, seeing as this is a food
    handling environment. This is going to increase your costs by quite a
    bit, and may require you to get a switch with the appropriate food
    handling rating. Many of these counters come with a mountable silicone
    rubber boot you can put over the front of the display, which will give
    you the appropriate rating.

    But if you don't have to be washdown rated, you can easily get the
    whole thing done for less than $40 USD for a new microswitch and a new
    counter. You also might want to ask around in your maintenance
    department -- they're typically pack rats, and may have the components
    waiting in a locker or drawer for you to pick them up.

    I'm not familiar with too many distributor sources in the UK, but you
    could do worse than getting an Omron H7EC-N at Farnell (3262807) for
    £35.02 in stock. A little pricey, but it's got everything you need
    for a washdown environment except the microswitch. It's got contact
    switching (set the DIP switch for 30Hz max), a reset button on the
    front panel as well as provision for external count, and it's also able
    to be hosed down if needed. Be sure to use the provided mounting kit,
    and use an approved gasket for mounting to a washdown box if you need

    Good luck
  8. david b

    david b Guest

    Many thanks for the advice, much appreciated.
    Will get onto it later this week
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