Tank Depth
in [Design]
|
Prev: LDR detector
Next: Fluorescent ballasts anyone?
From: Joerg on 9 Jul 2006 20:38 Hello James, >>> 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. >>> >>Sure, but there is fun in designing circuits :-))) > > Sure, but forcing a part to do what it wasn't designed for and not within > the specs when there is one that is doesn't sounf good to me. > Oh, I do that all the time. Thing is, the low pressure ones you mentioned look a bit flimsy. I'd prefer something that can be plumbed in. >> >>I assume you run it via a sprinkler controller or something like that, >>with a master pump output. For many of those you can buy a precipitation >>sensor. The really good ones may allow for gradual adjustment of the zone >>times depending on how much precipitation there was. > > Know of any ones like that? > Don't remember, have seen them at Home Depot. The Toro 12-station timer we have can be equipped with one so you could check their web site. I just didn't buy it because we really don't need that feature. Summers out here are nearly rainless. -- Regards, Joerg http://www.analogconsultants.com
From: James F. Mayer on 9 Jul 2006 21:56 "Joerg" <notthisjoergsch(a)removethispacbell.net> wrote in message news:dkhsg.62437$Lm5.21718(a)newssvr12.news.prodigy.com... > Hello James, > > >>>> 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. >>>> >>>Sure, but there is fun in designing circuits :-))) >> >> Sure, but forcing a part to do what it wasn't designed for and not >> within the specs when there is one that is doesn't sounf good to me. >> > > Oh, I do that all the time. Thing is, the low pressure ones you mentioned > look a bit flimsy. I'd prefer something that can be plumbed in. > Matbe I'll have to put thim in some sort of enclosure with pipe threads and pot them. >>> >>>I assume you run it via a sprinkler controller or something like that, >>>with a master pump output. For many of those you can buy a precipitation >>>sensor. The really good ones may allow for gradual adjustment of the zone >>>times depending on how much precipitation there was. >> >> Know of any ones like that? > > Don't remember, have seen them at Home Depot. The Toro 12-station timer we > have can be equipped with one so you could check their web site. I just > didn't buy it because we really don't need that feature. Summers out here > are nearly rainless. > I'll have to look the next time I'm in the one up the road. I was there today but I didn't have those on my list. I'll start a new list.
From: joseph2k on 9 Jul 2006 23:38 James F. Mayer 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. Er, no. Continuous purge air would give erroneous readings. Purge, stop, wait a little, then measure. Using aerator air for purge trades a pump for a bit of tubing, purge valve is still required though, potentially a good deal. -- JosephKK Gegen dummheit kampfen die Gotter Selbst, vergebens. --Schiller
From: YD on 10 Jul 2006 00:33 On Wed, 05 Jul 2006 21:56:33 GMT, Joerg <notthisjoergsch(a)removethispacbell.net> wrote: >Hello Joel, > > >>>c. PVC pipe with end cap, must be absolutely water tight. Copper pipe in the >>>middle that has an OD almost as large as the ID of the PVC pipe. Connect >>>oscillator circuit to it. This forms a capacitor where the capacitance >>>changes with the water level. >> >> You're using the container itself (55 gal. metal drum) as the other side of >> the capacitor... right? >> > >That's what the other port would connect to. Here is a similar example: > >http://www.elecdesign.com/Articles/Print.cfm?ArticleID=11491 > >Although I would not do that with a monostable but with a regular LC >oscillator. More stability, less drift (if built properly). Capacitive bridges aren't uncommon. Endress+Hauser has a range of them. Single teflon covered rod if the liquid is conductive, two rods side by side or concentric if it isn't. A bit of a hassle since they need to be calibrated in-situ. Largely superceded by ultrasonic and microwave systems. - YD. -- Remove HAT if replying by mail.
From: YD on 10 Jul 2006 00:41
On Sun, 09 Jul 2006 13:23:15 GMT, "James F. Mayer" <jfma(a)ix.netcom.com> wrote: > >"Joerg" <notthisjoergsch(a)removethispacbell.net> wrote in message >news:Gixrg.62605$fb2.62283(a)newssvr27.news.prodigy.net... >> Hello James, >> >>>> >>>>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? >>> >> >> True. But since you said you are in a hurry, wife breathing down your >> back, reminding you to get it done, saying there are lots more honey-dos >> on the list... >> > > What wife? I ain't got no steenking wife. > >>> >>> 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. >>> >> >> Sure, but there is fun in designing circuits :-))) >> > > Sure, but forcing a part to do what it wasn't designed for and not within >the specs when there is one that is doesn't sounf good to me. > A float, a pot, a weight, a pulley, maybe some gearing. Take it up from there. - YD. -- Remove HAT if replying by mail. |