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Discussion in 'Electronic Design' started by Don Y, Jul 21, 2013.

  1. Don Y

    Don Y Guest

    Hi,

    I need to instrument a domestic (commercial) potable water
    supply.

    Specifically, I need:
    - electrically operable stop for main supply
    - electrically operable stop for each sink, etc.
    - electrically readable flow meter capable of detecting
    small changes in flow rate (either instantaneously or
    with external computational assistance over short
    intervals) -- probably on a site-wide scale (e.g.,
    whole house, whole business, etc.)

    Since these are in the domestic/potable supplies, they
    have to be lead free, etc. (i.e., probably not "made in
    china" -- WTF? Do they have some large box of lead shot
    on the wharf and a rule that says everything exported
    must be rubbed in this bed for a few minutes before being
    placed on the boat???)

    And, since it will also have to work in a residential
    setting, probably available with 2xFIP or thereabouts.
    Probably 3/4" or 1" (most commercial settings are 2" or
    larger flanges)

    Ideally, the stops will be reasonably quick acting so they
    can be exercised "invisibly".

    Flow meter should be designed such that service personnel
    unfamiliar with these sorts of devices aren't placed in
    harms way when servicing the system.

    Of course, everything has to be "install and forget" (for
    a LONG time... not something that has to be maintained
    regularly; e.g., gate valves are out of the question).

    So far, my casual queries in some of the larger plumbing supply
    shops have been met with blank stares (c'mon... hasn't *anyone*
    purchased something like this in town??)

    Anyone *design* any of these devices? (I used to know a guy who
    designed mass flow meters but have since lost his contact info)
    Or, design anything like them *into* something??

    Thx,
    --don
     
  2. Guest

    Don Y :

    Same aioe.org troll airhead.
     
  3. Don Y

    Don Y Guest

    Hi Joe,

    "Stop" as in a valve that is intended to be used in a full-on/full-off
    configuration. I.e., not something that is used to adjust flow *rate*
    but, rather, to *gate* the flow on or off.
    Yeah, but unless I wanted to use one "as is", it would be tedious
    to repurpose such a thing (and, questionable as to whether or not
    it would then pass Code)
    That's an idea! Though the "potable water" use may get in the way
    there. Motorized might present some problems (as it would be hard
    to ensure enough power available to open/close them in the *absence*
    of ACmains)

    I'd also thought of these "interrupters" that are used to protect
    against flooding from ruptured washing machine hoses. But, not sure
    how they would scale (nor whether they would be appropriate for
    use on *potable* supplies).
    I've already used irrigation valves for the *outside* water
    distribution (i.e., for each irrigation zone as well as each hose
    bibb). But, again, not sure how well they would be "received"
    on potable use. I can just see an inspector looking at them
    and envisioning them *outdoors* and then getting into a Code war...
    Ideally, the municipality would make that "data" available to the
    consumer in real time (assuming you can't "corrupt" it and thus
    "steal" water). But, we don't have an instrumented meter and I
    suspect *asking* for one (if they would even entertain that
    request) and relying (*paying*) on the water department to install
    it would be insanely expensive.

    Apparently, also, these meters are notorious for their INaccuracy!
    (I should grab a bucket and do some first-hand measurements)
    I would like to be able to notice (in a residential setting):
    - nothing *should* be using water yet water is flowing
    I.e., a water line has ruptured (e.g., the supply to a
    toilet, dishwasher, washing machine/dryer, etc.) *or*
    something has a slow leak (like a toilet)
    - an additional 1.6 gallons just surged through the main in
    the last 12 seconds...
    - someone must be running the shower, etc.

    Thanks! I'll chase down those two leads! Sheesh, you'd think this
    was rocket science or somesuch... :<

    --don
     
  4. Don Y

    Don Y Guest

    Hi Tom,

    Exactly. I'm sure an inspector would quickly recognize an "irrigation
    valve" used in a potable water supply line and balk at the idea.
    OTOH, a valve certified as being suitable for use in domestic
    potable water applications at least gives you a foot in the door
    to argue for its acceptance.

    And, if you can find someplace that is already *using* such things,
    then all the more power to you!

    [Apparently, there are even tougher "lead" regulations coming down
    the road as I see more an d more manufacturers touting the lead
    content (lack thereof) in their plumbing fixtures]

    --don
     
  5. Don Y

    Don Y Guest

    Hi Joe,

    But, in each of these cases, the "load" end of the valve was not
    supplying DRINKING WATER to the residents!
    Back-flow preventer/anti-siphon device exists to prevent "surface
    water" (which, around here, often contains pesticides and herbicides)
    from being sucked into the municipal water supply in the (unlikely)
    event that the city loses water pressure (far more likely to occur
    when a fire crew is *pulling* water from a nearby hydrant and, in the
    process, sucking water off your front lawn via your garden hose or
    subterranean irrigation lines).

    I replumbed the irrigation system *and* hose bibbs to sit downstream
    of a "master valve/anti-siphon device" for exactly this reason (it's
    also a Code requirement -- though it seems to only be selectively
    enforced).
    I'm not sure of that. I've found these folks (and tradesmen, too
    often) to be very unimaginative/intolerant in what they consider
    "legitimate/legal/appropriate" -- especially given that these things
    become part of the home (i.e., not some "accessory" that you can
    remove at will).

    For example, I want to install a pressure reducing valve, here. That
    necessitates the addition of an expansion tank (though, interestingly,
    many folks seem ignorant of this!).

    But, the way the house is plumbed, installing such a tank would
    have to be "past" the hot water heater (though only a foot or so).

    Conceptually, this shouldn't make a difference (?). Water expanding
    from the water heater should be able to expand into this tank regardless
    of whether it is located "between the pressure regulator and the water
    heater" *or* "just past the water heater" (i.e., while still on the
    "regulated" side of the valve).

    Yet, ask a plumber and he'll give you the deer-in-headlights stare.
    When *pressed*, he'll cite "between the pressure regulator and the
    hot water heater". Trying to get him to explain why "just past the
    water heater" would be "UNacceptable" and he'll mumble and change
    the subject. (I've sprung this question on more than a dozen
    plumbers, so far!)

    [I.e., the folks who *make* the rules/Code obviously have a different
    level of understanding than those who implement/enforce them!]

    I'd like something I could point to (cite) before putting the
    house at risk (occupancy, resale, etc.). Ideally, "existing
    practice"!
     
  6. Guest

    The local appliance parts store will have solenoid valves for
    refrigerator ice makers that will get you part of the way there. The
    inlet will be something like a compression fitting for 1/4" tube and
    the outlet is either a fitting for 1/4" or so tube or a barb fitting
    that a rubber hose goes over. They almost always have a 120 V solenoid.

    Clothes washers and dishwashers have similar valves, but making the
    "potable" argument will be harder. The clothes washer valve will have
    2x 3/4" garden hose inputs and probably barb output. The dishwasher
    valve will be similar to the icemaker valve, but probably 3/8" in and
    out.

    One of these that I took apart was made by Eaton, but I get the
    impression that they will be confused if you want to buy 10 valves;
    they usually sell thousands at a time to OEMs.

    If you want a real, official valve, Asco sells a bunch of solenoid
    valves, and even has some listed as "Potable water and food service",
    with NSF approvals. The solenoids come in various AC and DC voltages.
    1/2" or 3/4" http://www.ascovalve.com/Applications/Products/ASCO-212Series-CompositeValve.aspx
    1/8" or 1/4" http://www.ascovalve.com/Common/PDFFiles/Product/8256_NSFR6.pdf
    The one electronic flow meter I once tried to use had an interesting
    spec: there needed to be a relatively long section of straight pipe
    (like 3 feet or 1 meter) on the inlet side, or else it would read
    incorrectly. We didn't have that much room, so we used a loop with the
    biggest radius we could, but that didn't work right.

    Offhand I don't know what to recommend. Omega has *one* NSF-rated flow
    sensor, 3/8" NPT, 4 gpm max, that can give you either ~5,000 or ~10,000
    pulses per gallon: http://www.omega.com/pptst/FTB-430.html
    If the stops are going to operate on flowing water often, consider that
    this will probably cause some impressive pressure spikes in the supply
    lines. You might want to install a water hammer arrester along with
    the stops.

    Standard disclaimers apply: I don't get money or other consideration
    from any companies mentioned.

    Matt Roberds
     
  7. Don Y

    Don Y Guest

    Hi Matt,

    I think trying to repurpose something intended to reside *inside*
    some other product is probably not the right way to proceed.
    Packaging, safety, etc. issues can raise eyebrows.

    Ideally, I was looking for a nice valve designed to be soldered
    (or FIP) into a copper line. Like any other valve you would encounter
    in home plumbing.
    I'd found the smaller valves previously and dismissed them as too
    small for all but toilet, ice maker, etc. One could argue that they
    *might* be acceptable for sinks despite the fact that most sinks are
    fed from 1/2" pipe (which is usually reduced to ~3/8 in the actual
    fixture and flex lines).

    But, these *look* like what I've imagined such a valve should look like!

    The larger units are news to me! Though they sure look like
    irrigation valves -- despite their certification! :-/ Given
    their stated application (e.g., water conditioners), I wonder if
    that suggests a reduced capacity/flow rate over what you would
    expect from a "normal" (gate, ball, etc.) valve of similar pipe
    size?

    I found this:
    <http://www.watercop.com/Purchase/ta...efault.aspx?SortField=DateCreated,ProductName>
    which appears to just be a traditional ball valve with an
    actuator (undoubtedly motorized) attached -- and some smarts to
    give it a defined role. I'd hate to have to go that route but it
    might be acceptable for the "main" (dealing with power outages
    would be an issue to evaluate... a "sane" strategy that is
    safe from exploit with only minor inconvenience?)
    Turbulence?

    I know some ultrasonic meters require a sizable straight length "in"
    the meter to work their magic. And, some mass flow meters that
    operate on the coriolis principle *need* a fair bit of size/loop.
    That would only work if I used several of them to monitor each place
    water is consumed (small diameter). Our main is 3/4" and I think
    the newer Code calls for a full *inch*! (this in a place where water
    Yes. I figure I could fit them in each location. They don't need
    to be "instant on/off". But, need to be fast enough that the
    measurement system can noticeably "see" their actions. E.g.,
    "slow close" valves could work but probably aren't necessary.

    E.g., if you can only measure at one point (main), one way to
    *guess* at where water is being consumed is to temporarily
    gate that point OFF and see if the flow rate at the measurement
    point changes. Think a flex line to a toilet has ruptured?
    Turn off the supply to that toilet and see if the metering
    unit "notices". Likewise, see if it *also* notices when you
    restore that service!

    [Granted, this isn't conclusive but can be *almost* so! Especially
    if you know what else is happening in the environment (i.e., no one
    *in* the bathroom so why does the water appear to be running??) ]
    Ah. I was going to tell them to be prompt with your payment!! :>

    Thx!
    --don
     
  8. Don Y

    Don Y Guest

    Hi Robert,

    Gack! $470? I guess that silver colored metal that it appears
    to be made out of must be *platinum*!! :-/
    Even *more* outrageous! Folks, we're in the WRONG BUSINESS! :>

    I should call the local water department and see where they get their
    meters from. At those sorts of prices (and questions over whether
    or not they are suitable for potable water), I would imagine it
    could be cheaper to pay gummit rates for one!! :-/
    In theory, this:
    <http://www.getfloodstop.com/Water_Heater_FloodStop_p/fs34npt.htm>
    should be rated for potable water ($125). But, it's so "consumery"
    that I don't find much hard data regarding its performance,
    certification, etc.

    (There are similar products -- other vendors -- for non-potable
    use like washing machine, dishwasher, etc. Though you can only
    assume the one for the water heater was designed with "human
    consumption" in mind)

    I'll have to look into metering technologies to see if there is
    anything more appropriate/affordable available. <frown>

    --don
     
  9. Solenoid valves. They're used in foodservice equipment
    for potable water. I don't know about your local codes, but they are
    going to be safe. Eg. Asco. Maybe find them cheap on eBay (that were
    used for controlling sewage flow or something).
    Try Gems. Eg. wetted materials Nylon, graphite-loaded PTFE bearings.
     
  10. soemthing like this? http://www.temcocontrols.com/products/5/28/water-meter.htm

    -Lasse
     
  11. Rob Gaddi

    Rob Gaddi Guest

    Hmm. Sparkfun seems to have a 3/4" one. Chinese yeah, but they're at
    least willing to claim RoHS on it.
    https://www.sparkfun.com/products/10456
     
  12. Guest

    One of the smaller Asco valves comes in both "vanilla" and "NSF"
    versions. As far as I could see from reading the specs, the difference
    was a different material used in an O-ring that contacted the fluid. If
    you can re-use all the tooling and just make a material change to gain
    certification, why not?
    I'm not sure. I bet there's a way to figure it, I just don't know what
    it is. Or, buy one of each, build a manifold that is reasonably likely
    to deliver about the same pressure to each valve, open the valves, turn
    on the water, and see which one fills a 5 gallon bucket the fastest.
    What is the end goal here? Are you trying to stop people from
    "stealing" water, or are you making a "water breaker box" that shuts
    off the line to a particular fixture if a pipe breaks? If it's the
    latter, consider the effect on the system leak probability that all
    these extra valves and flow sensors will have...

    Matt Roberds
     
  13. Don Y

    Don Y Guest

    Hi Matt,

    Sure, makes sense! But, why not make *both* versions NSF?
    (what's the downside of that O-ring substitution? Is it made
    of Unobtanium? Does it have a greatly reduced service life?
    Does it restrict the device to lower temperature applications?
    etc.)

    And, why can't the same sort of design be scaled up to 3/4"?
    (I imagine the larger valves are piloted)
    Yeah, but would you be able to declare that as a Truth? Something
    that others would be able to reproduce? Or, did you just get lucky??
    No. There are a couple of different goals behind the valves usage.

    In some cases, the valve is intended to be used to gate the flow
    off to keep water out of the "load". E.g., like a shutoff for
    washing machine/dryer (you want to make sure there is no water
    pressure in the flexible hoses that connect the appliances to
    the water supply when there is no *need* for that water to be
    supplied -- so a hose doesn't rupture and flood the house!).

    In some cases, the valve is intended to allow the flow to be
    enabled on demand. E.g., dispense water from the kitchen sink.

    These are the sorts of typical uses you would expect from a
    valve/stop.

    In *other* cases, the stop is a cheap way to monitor water use.
    I.e., putting flow meters on every possible place where water
    could be "consumed" is outrageously expensive. (and, only lets
    you *measure* flow; it gives you no *control* over that flow!)

    [For example, if I installed a flow meter in the line to the
    washing machine, I could *tell* if the hose had ruptured...
    but, I couldn't *do* anything about it! (except alert someone
    who is HOPEFULLY nearby!]

    Instead, if I can "precisely" (for suitable values of "precisely")
    monitor water flow rates AT THE MAIN (or, some small number of
    points that feed many "consumption points" *and* I can interrupt
    those consumption points on demand, then I can *infer* (with
    some variable level of certainty) where the water is being
    consumed. And, from that, make some assumptions about the likely
    activity involved.

    E.g., at 3AM, chances are, there is no "normal" water consumption
    in a particular environment. So, if I *see* water being consumed
    (because I am continuously watching the flow meter on the main),
    I have to wonder *why*.
    - Has a supply line to a toilet ruptured?
    - Is a toilet "running on"?
    - Is the refrigerator making ice?
    - Did someone get up to take a pee? Get something to drink??
    etc. Based on the rate, duration and volume, I can make some
    guesses and then explore those guesses -- by *closing* valves
    and seeing what effects this has on instantaneous water flow.

    E.g., if "1.6 gallons" of water flow in a ~10 second interval
    AND THEN STOP, someone probably flushed a toilet (of course,
    they could also have washed a dish, filled a jug of water,
    washed their hands, etc.).

    OTOH, if only a pint of water is consumed in a few seconds,
    it's probably the icemaker in the refrigerator.

    Or, if the water is consumed at a different rate or for a
    longer period, it's probably *not* a toilet flush -- though it
    could be a toilet that is "running on", ruptured flex line, etc.
    Try interrupting the flow of water to the toilets and see if
    this affects the rate that water flows. If the water is running
    for a LONG time, maybe interrupt the flow to the sinks (since
    a sink rarely uses water for long periods -- maybe it's the shower?)

    Has the water softener broken and is now overfilling the brine
    tank? Has the water heater started to leak? etc.

    Again, I can't be 100% sure of many of these deductions (ABSENT
    any constraints on other things happening at the time) but it
    gives me some knowledge *and* a means of protecting against those
    sorts of losses even if my deductions are wrong! ("No, the hot
    water heater was not leaking. Instead, someone left a faucet
    open intentionally to safeguard against frozen pipes, etc.")

    That's why the valves have to be "sort of" fast. I have to be able
    to see their actions "upstream" with limited resolution from the
    monitoring station.

    Make sense?

    --don
     
  14. josephkk

    josephkk Guest

    I don't know myself, but i do know people who do know. Could you provide
    me with a bit more information so i can at least point you to to the
    right vendors?

    ?-)
     
  15. Don Y

    Don Y Guest

    Hi Matt,

    Sure, makes sense! But, why not make *both* versions NSF?
    (what's the downside of that O-ring substitution? Is it made
    of Unobtanium? Does it have a greatly reduced service life?
    Does it restrict the device to lower temperature applications?
    etc.)

    And, why can't the same sort of design be scaled up to 3/4"?
    (I imagine the larger valves are piloted)
    Yeah, but would you be able to declare that as a Truth? Something
    that others would be able to reproduce? Or, did you just get lucky??
    No. There are a couple of different goals behind the valves usage.

    In some cases, the valve is intended to be used to gate the flow
    off to keep water out of the "load". E.g., like a shutoff for
    washing machine/dryer (you want to make sure there is no water
    pressure in the flexible hoses that connect the appliances to
    the water supply when there is no *need* for that water to be
    supplied -- so a hose doesn't rupture and flood the house!).

    In some cases, the valve is intended to allow the flow to be
    enabled on demand. E.g., dispense water from the kitchen sink.

    These are the sorts of typical uses you would expect from a
    valve/stop.

    In *other* cases, the stop is a cheap way to monitor water use.
    I.e., putting flow meters on every possible place where water
    could be "consumed" is outrageously expensive. (and, only lets
    you *measure* flow; it gives you no *control* over that flow!)

    [For example, if I installed a flow meter in the line to the
    washing machine, I could *tell* if the hose had ruptured...
    but, I couldn't *do* anything about it! (except alert someone
    who is HOPEFULLY nearby!]

    Instead, if I can "precisely" (for suitable values of "precisely")
    monitor water flow rates AT THE MAIN (or, some small number of
    points that feed many "consumption points" *and* I can interrupt
    those consumption points on demand, then I can *infer* (with
    some variable level of certainty) where the water is being
    consumed. And, from that, make some assumptions about the likely
    activity involved.

    E.g., at 3AM, chances are, there is no "normal" water consumption
    in a particular environment. So, if I *see* water being consumed
    (because I am continuously watching the flow meter on the main),
    I have to wonder *why*.
    - Has a supply line to a toilet ruptured?
    - Is a toilet "running on"?
    - Is the refrigerator making ice?
    - Did someone get up to take a pee? Get something to drink??
    etc. Based on the rate, duration and volume, I can make some
    guesses and then explore those guesses -- by *closing* valves
    and seeing what effects this has on instantaneous water flow.

    E.g., if "1.6 gallons" of water flow in a ~10 second interval
    AND THEN STOP, someone probably flushed a toilet (of course,
    they could also have washed a dish, filled a jug of water,
    washed their hands, etc.).

    OTOH, if only a pint of water is consumed in a few seconds,
    it's probably the icemaker in the refrigerator.

    Or, if the water is consumed at a different rate or for a
    longer period, it's probably *not* a toilet flush -- though it
    could be a toilet that is "running on", ruptured flex line, etc.
    Try interrupting the flow of water to the toilets and see if
    this affects the rate that water flows. If the water is running
    for a LONG time, maybe interrupt the flow to the sinks (since
    a sink rarely uses water for long periods -- maybe it's the shower?)

    Has the water softener broken and is now overfilling the brine
    tank? Has the water heater started to leak? etc.

    Again, I can't be 100% sure of many of these deductions (ABSENT
    any constraints on other things happening at the time) but it
    gives me some knowledge *and* a means of protecting against those
    sorts of losses even if my deductions are wrong! ("No, the hot
    water heater was not leaking. Instead, someone left a faucet
    open intentionally to safeguard against frozen pipes, etc.")

    That's why the valves have to be "sort of" fast. I have to be able
    to see their actions "upstream" with limited resolution from the
    monitoring station.

    Make sense?

    --don
     
  16. some dissolve in oil, some swell in water, some can take heat,
    some work when cold

    -Lasse
     
  17. Jasen Betts

    Jasen Betts Guest

    Tradesmen work to "the code", if you want to do something off-code
    you need to get the apropriate engineer to sign off (or design it)
    and then it's OK. By working to the code they are protected from
    screwing up the desin of the system, but also constrained from
    many alternative designs.
    Could you bypass the heater, visit the tank and then loop back to the
    heater, sometimes it's easier to just comply.
    Perhaps there's an issue with scale or gas produced in the heater getting
    into the tank?
     
  18. Don Y

    Don Y Guest

    Hi Robert,

    Well, maybe it's just really really *small*!! :>
    They make these. They are called actuators. In the $200 range
    and essentially exactly what you have described. I.e., you can
    monitor whether the "valve" -- technically, the handle -- is in
    the full open or full closed position. This is especially
    important for ball valves as any position "in the middle" will
    result in the valve failing over time (as the water scours
    a new path through the ball!)
    Yeah but the resolution is really *coarse* (1G). I think that will
    be the problem I will face: these sorts of devices are probably
    aimed at monitoring overall consumption over long periods of time
    whereas I am more interested in monitoring *rate* (I can always
    integrate over an infinite interval but I can't get any more resolution
    than the device affords)
    Thanks, I will poke around. I should probably call the local water
    company and see what options present themselves on that front.
    Maybe modify (externally) the metering of an existing meter to
    get the increased resolution?

    --don
     
  19. Don Y

    Don Y Guest

    Hi Jasen,

    "In theory", that's the case. In practice... <shrug> Talk to
    any tradesman and he'll have numerous "Code War" stories for you
    (i.e., the Inspector is often the final authority on Code issues
    and, in many jurisdictions, can't be "appealed"/litigated)
    Yup. My attitude is that the Code(s) exist for a reason. And, the
    folks writing those rules are probably a helluvalot smarter than I
    when it comes to those issues! But, getting *clear* explanations
    (interpretations) of their meaning and intent is difficult, at best!
    It would be "tedious", at best. Replacing the water heater at
    a later date would be complicated by that sort of pipework.

    And, it's not even a case of compliance vs. getting a variance!
    I can't get anyone to *swear* to "what's correct"! It seems,
    in many cases, folks just adopt a "that's the way it's BEEN done"
    which doesn't mean that's the *only* way it *can* be done
    (and still comply).

    E.g., dishwashers are typically installed adjacent to the sink.
    And, *typically*, the plumbing and electrical connections to the
    dishwasher are fed from *under* the sink, through the side of the
    "sink base (cabinet)" to the dishwasher. But, that's not a
    "requirement".
    Dunno. Conceivably, an excessively LONG pipe feeding the expansion
    tank *downstream* from the water heater could pose some problems
    but that would be easy to codify. E.g., there are rules regarding
    what sort of rise is required for a given length of a given diameter
    drain line to ensure water does flow in that line relying solely on
    gravity.

    <shrug> Frustrating when you are used to fetching specs out of
    a datasheet, etc.
     
  20. Don Y

    Don Y Guest

    Hi Michael,

    The ones that I have seen are too "integrated" into the
    functionality of the softener. E.g., it's like one giant
    actuator that alters multiple water paths at the same
    time (I'm guessing it pushes the brine through the
    resin and recharge the brine tank at the same time -- or,
    in a fixed/timed sequence).
     
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