Tank Depth
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From: Joerg on 6 Jul 2006 13:59 Hello Rich, > >>Paint, exposed metal, all that will rot over time. I have even seen >>steel corrode although it was sold as stainless. In an application like >>this ideally you need something that you can build and forget for a few >>years. > > And your objection to making a yearly inspection of your facilities would > be....? ;-) > This looks like a rig for personal use. Yearly inspections are ok but if you find something amiss on every one of these it'll become a hassle. It's always best to design something to last literally forever. -- Regards, Joerg http://www.analogconsultants.com
From: James F. Mayer on 6 Jul 2006 19:31 "Joerg" <notthisjoergsch(a)removethispacbell.net> wrote in message news:4ccrg.62358$fb2.3135(a)newssvr27.news.prodigy.net... > Hello Rich, > >> >>>Paint, exposed metal, all that will rot over time. I have even seen steel >>>corrode although it was sold as stainless. In an application like this >>>ideally you need something that you can build and forget for a few years. >> >> And your objection to making a yearly inspection of your facilities would >> be....? ;-) >> > > This looks like a rig for personal use. Yearly inspections are ok but if > you find something amiss on every one of these it'll become a hassle. It's > always best to design something to last literally forever. > All of the suggestions are good but one of the problems is that all of the drums are plastic, probably something I should have mentioned at the beginning. I have around 25 drums in the system. and would like to monitor each drum individually as well as a whole. I came across these pressure sensors: the MPX2010 and its amplified version the MPX5010 in my rummaging through DigiKey. Has anyone had any experience with them? Do you think they would work in the harsh environment of a backyard in West Central Florida? What case styles would you suggest? Could I build them in a small potting box and pot them to make them more weather resistant and what sort of potting would I use?
From: Paul Hovnanian P.E. on 6 Jul 2006 20:18 Jim Thompson wrote: > > On Wed, 05 Jul 2006 00:22:54 GMT, "James F. Mayer" > <jfma(a)ix.netcom.com> wrote: > > > > >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote in > >message news:r50ma2dsib6tk887j2p8r5522bq279j411(a)4ax.com... > >> On Tue, 04 Jul 2006 15:50:22 -0700, "Paul Hovnanian P.E." > >> <paul(a)hovnanian.com> wrote: > >> > >>>"James F. Mayer" wrote: > >>>> > >>>> I believe that a short time ago there was a discussion about this. but > >>>> depending on the head of the tank one could use an MPX5000 series > >>>> pressure > >>>> sensor with a dip tube or am I too late? > >>>> > >>>> I have a number of 55 gal drums of water that I would like to know > >>>> the > >>>> depth of in my rain water gathering system so that I don't pump it dry > >>>> and > >>>> ruin a sprinkler pump. I am going to use one of them per drum to > >>>> monitor > >>>> the levels. I believe that the pressure of one foot of head is .43 PSI > >>>> and > >>>> that a drum is about 3 feet deep, giving a pressure of 1.29 PSI. Does > >>>> this > >>>> sound correct? > >>> > >>>That sounds about right. However ... > >>> > >>>This technique of measuring tank depth (quantity) may not work well over > >>>a long period of time. In a washing machine, for example, the dip tube > >>>only needs to maintain a reading for the duration of the fill cycle. I > >>>suspect that slow leakage or air in the dip tube dissolving into the > >>>water over longer periods (days, weeks) may reduce its accuracy. > >>> > >> > >> That's the scenario I've been pondering. I'm trying to figure a way > >> to measure (salt) aquarium level, for top off, that's reliable. > >> > >> I'm pondering a combination of washing-machine-style dip tube plus a > >> (electro-mechanical) timer, to ensure that the tube clears before > >> refill. > >> > >> Hopefully that would prevent false overfills due to air seepage from > >> the dip tube. > >> > > > > Running some of the aerator air through the dip tube would solve that > >problem, I'd think. > > > > Jim, Please elaborate, I'm not seeing what aerator air would do for > you. Thanks! > > ...Jim Thompson John Larkin mentioned a bubbler earlier in this thread. All you'd have to do is to tap into the aerator system and meter a small amount of air into the dip tube. I'd think you'd want a small amount so that the pressure variations caused by larger bubbles separating wouldn't cause fluctuations in readings. The pressure in the dip tube would equal the pressure of its depth and bleeding a tiny amount of air in makes up for leakage and dissolving air. -- Paul Hovnanian mailto:Paul(a)Hovnanian.com ------------------------------------------------------------------ Software Engineering is like looking for a black cat in a dark room. Systems Engineering is like looking for a black cat in a dark room in which there is no cat. Knowledge Engineering is like looking for a black cat in a dark room in which there is no cat and somebody yells, "I got it!"
From: Joerg on 6 Jul 2006 20:31 Hello James, >> >>>>Paint, exposed metal, all that will rot over time. I have even seen steel >>>>corrode although it was sold as stainless. In an application like this >>>>ideally you need something that you can build and forget for a few years. >>> >>>And your objection to making a yearly inspection of your facilities would >>>be....? ;-) >> >>This looks like a rig for personal use. Yearly inspections are ok but if >>you find something amiss on every one of these it'll become a hassle. It's >>always best to design something to last literally forever. > > All of the suggestions are good but one of the problems is that all of > the drums are plastic, probably something I should have mentioned at the > beginning. Argggh... coulda told us earlier. .... Forgiven. > .. I have around 25 drums in the system. and would like to monitor > each drum individually as well as a whole. > With proportional pressure sensors that is going to become expensive. Unless money is not too important here I'd go with float switches. > I came across these pressure sensors: the MPX2010 and its amplified > version the MPX5010 in my rummaging through DigiKey. Has anyone had any > experience with them? Do you think they would work in the harsh environment > of a backyard in West Central Florida? Probably not. Also, note that only one of the 5010's is in stock, and they've got just 55 of them (seems you'd need 25 of these plus spares). > What case styles would you suggest? Could I build them in a small > potting box and pot them to make them more weather resistant and what sort > of potting would I use? > I'd look for something more industrial. Check Honeywell and the local Grainger outlet. Ideally I'd want something where I could drill a hole, cement in a fitting and then screw the sensor in with Teflon tape. IOW a clean plumbing job, no kludges. IIRC the Honeywell 236PC series has that thread but you'd have to check whether it fits, gives you the desired resolution etc. Whatever you do keep in mind that stuff like this may have to be serviced and repaired. Murphy's law stipulates that there will be a driving rain, gale force winds and some hail when that happens. -- Regards, Joerg http://www.analogconsultants.com
From: James F. Mayer on 6 Jul 2006 22:03
"Joerg" <notthisjoergsch(a)removethispacbell.net> wrote in message news:mXhrg.127309$dW3.53031(a)newssvr21.news.prodigy.com... > Hello James, > >>> >>>>>Paint, exposed metal, all that will rot over time. I have even seen >>>>>steel corrode although it was sold as stainless. In an application like >>>>>this ideally you need something that you can build and forget for a few >>>>>years. >>>> >>>>And your objection to making a yearly inspection of your facilities >>>>would >>>>be....? ;-) >>> >>>This looks like a rig for personal use. Yearly inspections are ok but if >>>you find something amiss on every one of these it'll become a hassle. >>>It's always best to design something to last literally forever. >> >> All of the suggestions are good but one of the problems is that all >> of the drums are plastic, probably something I should have mentioned at >> the beginning. > > > Argggh... coulda told us earlier. > > ... Forgiven. > > >> .. I have around 25 drums in the system. and would like to monitor each >> drum individually as well as a whole. >> > > With proportional pressure sensors that is going to become expensive. > Unless money is not too important here I'd go with float switches. > But where is the fun in designing curcuits? > >> I came across these pressure sensors: the MPX2010 and its amplified >> version the MPX5010 in my rummaging through DigiKey. Has anyone had any >> experience with them? Do you think they would work in the harsh >> environment of a backyard in West Central Florida? > > > Probably not. Also, note that only one of the 5010's is in stock, and > they've got just 55 of them (seems you'd need 25 of these plus spares). > I was thinking just 2 to get on with the experimentation and then, when I have the bugs worked out, get more. I am not in a real hurry. Just something I thought about when I started to run sprinkler lines. > >> What case styles would you suggest? Could I build them in a small >> potting box and pot them to make them more weather resistant and what >> sort of potting would I use? > > I'd look for something more industrial. Check Honeywell and the local > Grainger outlet. Ideally I'd want something where I could drill a hole, > cement in a fitting and then screw the sensor in with Teflon tape. IOW a > clean plumbing job, no kludges. IIRC the Honeywell 236PC series has that > thread but you'd have to check whether it fits, gives you the desired > resolution etc. > The lowest pressure rating that I saw was 15 PSI. Too high and I would have to construct some sort of amplifier to bring up the voltrages to reasonable levels. The pressure I believe that I would be working with is about 1.29 PSI (.43*3 Ft.). The range on the MPX5010 is 1.45 PSI and is amplified to have a F/S output of 4.475 VDC with a F/S span of 4.275 with a supply volyage of 4.75 VDC. > Whatever you do keep in mind that stuff like this may have to be serviced > and repaired. Murphy's law stipulates that there will be a driving rain, > gale force winds and some hail when that happens. Then the irrigation pump shouldn't be running. Maybe I should add a precipitation detector also? |