[TheForge] OT - Water pressure problem.

Mon May 16 01:25:03 EDT 2011

Bruce...look for a company that does hydrostat testing of high pressure tanks. 
They are often little one man outfits and after they mark them as failed for 2250 PSI, they become scrap in their eyes.
Most failed tanks just expanded a little too much at 5/2 of working pressure.  Or that's how it used to be.
Your 200PSI application is no problem.
Another option is old propane tanks, but they're a hassle to clean out.
Overkill on pressure capacity is very desirable.

On May 15, 2011, at 5:45 PM, Bruce Freeman wrote:

> I've had two ideas since first asking.  One is to mount a plastic
> barrel horizontally on four or six legs as a water tower, but lean
> this structure against the back of the garage, which (1) hides it from
> casual view, (2) provides the extra rigidity from the existing
> structure, and (3) allows me to use the space beneath as a "shed", if
> I enclose it.
> 
> But on reading Peter's contribution, it struck me that I could
> pressurize a tank using air from an air compressor.  When the water
> level got too low, the air pressure would be released until low enough
> for the water pump to handle.  The water pump would refill the tank,
> then the water pump would shut off and the air pump would come on and
> pump the tank back up to operating pressure.  Clearly, one would want
> a tank large enough for the watering job at hand.  And a manual switch
> to initialize the refill cycle would be handy. Main advantage -- no
> tower structure to build and worry about.  Main disadvantage --
> obtaining a suitable tank.  Anyone know a source of such tanks --
> cheap?
> 
> 
> 
> On Sun, May 15, 2011 at 4:18 PM, peter fels <artgawk at thegrid.net> wrote:
>> Storing water under the house in sealed tanks has thermal mass virtues.
>> or short term use, an external  tank ,with water above pressurized air
>> ought to suffice. No bladder necessary....just drain and recharge every month or 2.
>> I've about 300 gallons available for fire fighting like that.
>> The pump could be electric on a pressure switch..all commonly available and modestly priced...
>> Or a small solar powered piston pump might suffice as well.
>> A tank atop a n upright pipe promises the least upkeep and lots of design freedom.
>> I think you can go to about 30' up with a centrifugal pump. Beyond that you'll want a piston or roller pump.
>> I've long wanted to build a rigid, flat, black tank with glass covering,
>>  that would pump with no moving parts, by the daily heating and expansion of the water...
>> OK the check valve is a moving part.
>> 
>> 
>> On May 14, 2011, at 3:05 PM, Bruce Freeman wrote:
>> 
>>> Once again I'm using the broad knowledge base represented by this
>>> group for an OT problem.
>>> 
>>> I have just installed rain barrels at all my downspouts, including a
>>> 250-gallon tank at one of them.  I plan to siphon or pump water
>>> between them to maximize capacity.
>>> 
>>> However, none of these are more than 16" above the ground -- two
>>> cement blocks.  That means that there's little water pressure
>>> available, making using the water inconvenient.  I could rig a pump to
>>> go on anytime I need water, but a more elegant solution would be to
>>> use that pump to keep an elevated tank (water tower) filled between
>>> limits.
>>> 
>>> What I'm thinking is to use a fairly small plastic tank -- 15 or 20
>>> gallons (i.e., ~150 lbs maximum), and to mount it high enough to
>>> provide reasonable water pressure.  In use, the pump would probably
>>> come on every once in a while, because the tank would be fairly small,
>>> but at least it wouldn't be running continuously or with no flow.
>>> 
>>> Now, to get 15psi I'd need a tower of over 30', and that's out of the
>>> question.  I'd like something as low as possible and as small as
>>> possible.  So, the first question is what is the lowest useful water
>>> pressure for use around yard and garden?  I don't need to run
>>> sprinklers, but would like to use drip hoses.
>>> 
>>> Possibly a water tower isn't the proper solution.  What other
>>> solutions exist?  What I'm aware of is a pressurized system, in which
>>> the pump fills an accumulator tank, or something of the sort, which
>>> then discharges for a while before the pump comes on again.  This
>>> strikes me as expensive, and i'd like to keep expenses low.
>>> 
>>> If it were possible to do, one potentially elegant solution would be
>>> an accumulator tank that would be filled either with city water or
>>> pumped rain water.  There'd have to be a barrier between them, and the
>>> side that would accept the city water would have to be clean and
>>> isolated from the rain water side (which must be assumed to be
>>> contaminated with various environmental contaminants, not the least of
>>> which would be bird feces).  If I put a check valve to keep the "city
>>> water" from backing up into the city piping, this might even be legal!
>>> I toss it out mainly for discussion, as I really don't see much
>>> advantage relative to an air bladder accumulator.
>>> 
>>> So, regale me with your wisdom, o metalworkers and artists of reality!
>>> --
>>> Bruce
>>> NJ
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> 
> 
> 
> -- 
> Bruce
> NJ
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