Entropy

Relax in southern comfort on the east bank of the Mississippi. You're just around the corner from Beale Street and Sun Records. Watch the ducks, throw back a few and tell us what's on your mind.
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mediatechnology
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Re: Entropy

Post by mediatechnology » Sun Dec 30, 2018 8:57 am

In hind sight when the big water is flowing strong it can pick up and move gravel too. :lol:
My neighbor to the south of me who overlooks our shared creek has reported seeing engine blocks deposited and then washed away with the next rain.

I'm glad I didn't see that one when it had been dropped there by the flowing water or I would have tried to get it out.
Now that I know I'll let mother nature finish the job.

Dunno if this helps but I've been told that it takes 2-3 feet/second of flow for a pipe to self-clean.
For that reason the trend in residential sewer pipes is to move from 4" to 3" diameter.
https://ka-electronics.com

The "Countering Disinformation And Propaganda Act" https://www.zerohedge.com/news/2016-12- ... da-act-law
"'NewsGuard' app gives news sites 'trust' ratings & targets alternative media. What could go wrong?" https://www.rt.com/usa/448555-newsguard-app-fake-news/
"A New Neocon-Backed Narrative Control Firm Works To Destroy Alternative Media"
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JR.
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Re: Entropy

Post by JR. » Sun Dec 30, 2018 11:00 am

mediatechnology wrote:
Sun Dec 30, 2018 8:57 am
In hind sight when the big water is flowing strong it can pick up and move gravel too. :lol:
My neighbor to the south of me who overlooks our shared creek has reported seeing engine blocks deposited and then washed away with the next rain.

I'm glad I didn't see that one when it had been dropped there by the flowing water or I would have tried to get it out.
Now that I know I'll let mother nature finish the job.

Dunno if this helps but I've been told that it takes 2-3 feet/second of flow for a pipe to self-clean.
For that reason the trend in residential sewer pipes is to move from 4" to 3" diameter.
I am not sure that computes. Flow should be slower/restricted by smaller cross section. Perhaps larger pipe does not help commensurate with the extra expense. {web advice suggests 3" for one toilet, 4" if two toilets feed same pipe.}

Yes, I respect the water when it is several feet deep and flowing hard. I see many odd things come down my ditch, but they must fit through 2' culverts uphill from me.

My small floats arrived and I can screw them to the pipe end grilles to force the pipe to mainly skim water from near the top of the rain ditch flow (should be less silt at top than bottom... I hope). I still wonder where my 50# of gravel ended up... :roll: In hindsight not very wise for me to put it all right by the drain inlet. It probably helped the sand accumulate in my old drain pipe...

This time around I'll do better if I just don't repeat my mistakes :lol:

JR

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mediatechnology
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Re: Entropy

Post by mediatechnology » Sun Dec 30, 2018 1:13 pm

The examples here show 3" building sewer lateral line diameter: http://www.homeownersnetwork.com/bookto ... pipe-size/

IIRC there wasn't much cost difference between 3 and 4" since the bulk of the cost was the 125' trench through solid limestone.
Flow velocity can be increased by either increasing the slope of the pipe or by using a smaller diameter.
http://www.hancor.com/daids/dh34_minimum.asp
Seems counter-intuitive...
https://ka-electronics.com

The "Countering Disinformation And Propaganda Act" https://www.zerohedge.com/news/2016-12- ... da-act-law
"'NewsGuard' app gives news sites 'trust' ratings & targets alternative media. What could go wrong?" https://www.rt.com/usa/448555-newsguard-app-fake-news/
"A New Neocon-Backed Narrative Control Firm Works To Destroy Alternative Media"
https://www.zerohedge.com/news/2019-01- ... tive-media

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JR.
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Re: Entropy

Post by JR. » Sun Dec 30, 2018 5:06 pm

mediatechnology wrote:
Sun Dec 30, 2018 1:13 pm
The examples here show 3" building sewer lateral line diameter: http://www.homeownersnetwork.com/bookto ... pipe-size/

IIRC there wasn't much cost difference between 3 and 4" since the bulk of the cost was the 125' trench through solid limestone.
Flow velocity can be increased by either increasing the slope of the pipe or by using a smaller diameter.
http://www.hancor.com/daids/dh34_minimum.asp
Seems counter-intuitive...
I claim no expertise about sewer design... but on the subject (TMI warning), when I am experiencing unusually heavy rain run-off (like recently) my toilet does not flush completely immediately but only slowly goes down. My toilet bowl is well designed so holds one flush in the bowl so no floor mess as long as I am patient.

My suspicion is that the town sewer system is somehow corrupted by the town storm drains. When I rains hard I see water coming up out of a manhole near my back ditch (I think that is a storm drain manhole). This could be really exciting if it backed up a couple feet higher. My guess is my sewer main is partially full of water so toilet flush only slowly flows out. :lol: (Only occurs a couple times a year but I may talk to the town about it again.)

My hands on experience with fluid flow dynamics is mainly related to too much time as a youth wrenching on cars. In that world there is a different dynamic but generally if you want more flow you need more cross sectional area. Speaking of less area for higher velocity my daily driver is a 4 valve per cylinder motor. And there are separate runners for half the intake valves with a butterfly valve to close them off at low RPM to provide higher velocity for optimal fuel turbulence/mixing with air. The car intake is nominally a fixed volume (engine displacement) system so same volume of air through less valves makes for higher velocity.

On the output (exhaust) side bigger is generally better for less back pressure and more flow.

=====
DSCF0091.JPG
This is crude proof of concept for my float assisted pipe drain inlets... I need shorter screws and washers, but concept looks like it could work. I am unsure how much difference this makes. :roll: When water is high and flowing fast, the silt probably passes through, when slow may not help.
DSCF0089.JPG
For chuckles I decided to look at the output side of my front culvert across the street... I have seen similar elephant ear weeds in my uphill neighbor's rain ditch... coincidence I think not.

Thinking backwards I need to stop trenching silt out of my mid-side ditch when any water is flowing at all... this just releases the beast. Ideally I need to dig it out when completely dry, maybe a week or more from now. :oops:

JR

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JR.
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Re: Entropy

Post by JR. » Sun Dec 30, 2018 10:44 pm

I feel a little lax about my typical entropy posts... don't worry stuff is still breaking and getting fixed (or not).

=== edit

My inner nerd finally said no mas.... the variable solar driveway lamp behavior was making me nuts... Since the sun is not predicted to return until friday, the night light on time is briefer than before.
DSCF0083.JPG
Not a great picture but too late, it is already out by my driveway charging one lamp with both solar cells (wired in parallel). Hot melt is holding the second cell on.

Up close the two cells look different. One has a greenish tint when you look at it from about a 30 degree angle, the other does not have an off angle color change.

I ordered some replacement lamps, only $3 each. I thought these two were from the same production run but clearly used different solar cells. They look like similar output voltage on the bench unloaded. I am optimistic that this will max out the charge from low sunlight today

----
More stories to come, I embraced some gordian knot solutions for nagging problems.. I'll report after they work, assuming they work.

====
Got less than 1" of rain overnight, but with the ground saturated all that rain water ends up flowing through my ditch... My far back culvert pipe is clogged with leaves... Small branches help trap leaves and slow/clog water flow. Even with my high water boots (almost up to my knee ) water was too deep to get close to the pipe... I got close enough from the sides to get some water moving.

I also had to clear the grille for a french drain I buried in my front yard a few years back because it was clogged with leaves and dry grass. Clear and draining now.

All the water flowing through my open trench is eroding it wider... I might have room to lay the pipes side by side...(I hope not) but possible in some places.

I like to blame my neighbors yard for the sand/silt, but I see some new silt coming from another ditch, so I am contributing plenty of silt/sand myself.

The more I do, the more I need to do.... :oops:

JR

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JR.
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Re: Entropy

Post by JR. » Tue Jan 01, 2019 2:50 pm

DSCF0084 copy.JPG
Here is a better picture of my franken-lamp. You can clearly see the different tint of the two solar cells.

Last night with the two cells in parallel was inconclusive. Light stayed lit for less than 3 hours.

This morning I rewired the two solar cells in series and they definitely make more voltage in low light. I'll give a report after tonight. I am optimistic, but not very comfortable with two different looking solar cells.

[edit OK results are in and franken-lamp was lit for 4 hours last night so a full hour longer. This is far from a controlled scientific experiment (light levels are not controlled), but moving in the right direction. Still raining so we'll see... /edit]
------
I am slowly coming to the realization that I have met the enemy causing my drain pipe to clog up, and it is me. :oops: I spend too much time dredging silt/sand from my ditches uphill from my drain while water is flowing... I am effectively stirring up silt to flow down and clog my drain pipe. :o

Back ditch is draining pretty well now with trench wide open... I got another half inch rain last night, so I don't expect it to dry up until maybe next week. I need it almost dry to set final pitch of the trench.

As often I have probably been overthinking this... :lol:

----

I have trash and leaves clogging my far back culvert pipe... not that important since it doesn't drain very low but might as well try to clear it out.

JR

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JR.
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Re: Entropy

Post by JR. » Wed Jan 02, 2019 10:29 am

Flash flood watch all day tomorrow (raining now).

I hope I cleared enough sticks,leaves,pine straw, and trash out of back culvert that good flow will finish flushing it out... maybe 50-50 chance of that.

I am settling on a final plan, while I still have some details to work out. This is apparently not a unique problem and they make fine mesh filter bags all the way down to 1 micron which is probably too fine. It will be far easier to replace or clean clogged filter bags than replace buried drain pipes again.

Image

As all too often occurs, I was overthinking this too.... :lol:

JR

billshurv
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Re: Entropy

Post by billshurv » Wed Jan 02, 2019 6:25 pm

Amongst the post xmas stash of things to fix (mainly toys) I need to sort out a niggle with the baby monitor remote. About once a week it gets a poor connection to the AA rechargables inside and makes a loud 'tick' through the speaker every 5-10 seconds. Pull the batteries and swap their positions and all is good again for another 1 to 10 days. no obvious corrosion. What am I missing?

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JR.
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Re: Entropy

Post by JR. » Wed Jan 02, 2019 6:36 pm

billshurv wrote:
Wed Jan 02, 2019 6:25 pm
Amongst the post xmas stash of things to fix (mainly toys) I need to sort out a niggle with the baby monitor remote. About once a week it gets a poor connection to the AA rechargables inside and makes a loud 'tick' through the speaker every 5-10 seconds. Pull the batteries and swap their positions and all is good again for another 1 to 10 days. no obvious corrosion. What am I missing?
I use many AA batteries in my drum tuners so I see a few issues.

Dry (low current ) connections can suffer from surface oxidation... Like I said I just spin the batteries in place to make them happy (I think).

I have seen far more exciting issues with battery spring contacts shorting hot to ground (I stopped buying that brand).

JR

billshurv
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Re: Entropy

Post by billshurv » Wed Jan 02, 2019 7:35 pm

Hard to spin these due to the contact design which is why I swap them. I may for a laugh try DeoxIT next time it happens.

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