Flow meters: a blessing in disguise. a pleasant luxury for the last darkroom?

Discussion in 'Darkroom Developing and Printing' started by winddancing, Jan 23, 2005.

  1. winddancing

    winddancing Guest

    With several washers, a processor or two, that could be operating
    simultaneously, how do you determine the distribution/use of flow meters?
    One for each type of usage? Is it a just convenience to quickly adjust
    volumes, or a quick on-going visual monitoring check to make sure that an
    inadequate volume is going through? Are they little blessings that are too
    easily ignored for their lack of necessity? Users responses would be more
    valuable than theoretical consensus.
    winddancing, Jan 23, 2005
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  2. 1 flow meter per controlled flow: one for each washer [if there is
    no tempering valve you may want to monitor hot and cold separately],
    one for each processor, one for the coffee maker -- just kidding.
    They measure flow, not volume, as in gallons/minute, but I think that
    is what you mean. There are some that measure volume by integrating
    flow: these are _not_ what you want.
    Well, most folks try to make sure there is an adequate volume, but if you
    insist ...
    'Little blessings'? That's a phrase I have never heard applied
    to a flow meter.

    I take it you are looking at meters of this type:


    Sometimes called a 'Dwyer' meter, after the name of the most common maker,
    sort of like Kleenex.

    The upside is

    o the right amount of water is flowing to wash prints etc.
    o water isn't wasted

    The downside is

    o the meter may cost more than the water saved,
    though if it keeps prints from staining it's cheap

    I occasionally calibrate my 'flow sense' by filling a litter graduate
    while timing how long it takes to fill. I can usually set flow to
    within 20% now that I know what 1 gal/min looks like when it comes out
    from the tap.

    The problem I have is the valves creep and water flow changes
    a lot over time and so I have to recheck every few minutes until things
    become stable.

    If your washers and processors are more-or-less permanently plumbed
    into the water line then I think flow meters are a good idea.

    If you use a rubber fitting or quick connect to hook to the faucet and
    your valves and water supply are stable then checking the flow visually
    every now-and-then is probably good enough.

    I would check ebay for flow meters. Don't pay more than $5 for a used
    one. Make sure it is not a 'gas flow meter': you want one for GPH, not
    SCFH or LPM. If you know someone who works in chemical, food, power etc. plant
    they may be able to get you some from the scrap heap [no five finger
    discounts: most firms have a heap of old junque].

    The nice meters have a little control valve on them that makes adjusting
    the flow very easy. Plumbing taps/valves are not made for fine
    flow control.
    I use really big ones in industrial settings, and really tiny ones
    in laboratory instrumentation. Not the same sort of visual ball-in-a-tube
    meters, though.
    Nicholas O. Lindan, Jan 23, 2005
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  3. winddancing

    Ken Hart Guest

    I have a flow meter/temperature mixing/filter panel in both my darkrooms. In
    the RA-4 minilab room, the minilab calls for a flow rate of 2GPM. The
    plumbing allows a max of 6GPM, which I use for filling the tanks, then I
    bring it down to 2GPM.
    In the manual/film darkroom, the flowmeter lets me know if the water flow is
    sufficient for the wash rate I want/need. If I want 6 water changes in a 3
    minute time period and I'm using a one gallon tank, then I need 2GPM.
    I would think that you need a flowmeter for each device that requires a
    measured flow. If you were running several devices, I suppose it would be
    possible with the proper plumbing to set up each device with a temperary
    flowmeter, then remove it.
    Ken Hart
    Ken Hart, Jan 24, 2005
  4. winddancing

    Ken Hart Guest

    Off-topic story: recently I moved my coffee maker into the darkroom (it was
    convenient, and it seemed to make sense to use filtered water in it!). When
    I moved it, I decided that would be a good time to clean it, but I didn't
    have any vinegar to run thru it. I used stop bath. Did a good job, but hot
    stop bath really stinks!

    Ken Hart
    Ken Hart, Jan 24, 2005
  5. I share the distilled water between making up developer and making
    up coffee. Same coffee maker for 22 years.
    Nicholas O. Lindan, Jan 26, 2005
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